Density altitude is the biggest factor in aircraft take off on a given runway length, temperature, and altitude. I know this from firsthand experience as I used to be a private pilot – until my hearing got so bad that I decided I was a danger to myself and others. This study published in the Bulletin of the American Meteorological Society claims the number of days with a density altitude issue at some airports will increase per RCP model scenarios in 2050-2070. Of course they are assuming that the RCP models produce an accurate output, and that airplanes of the 2050-2070 era have the same airfoil efficiency and takeoff power of today.
Climate change and the impact of extreme temperatures on aviation
Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027, USA.
Abstract
Temperature and airport elevation significantly influence the maximum allowable takeoff weight of an aircraft by changing the surface air density and thus the lift produced at a given speed (Anderson 1999). For a given runway length, airport elevation, and aircraft type there is a temperature threshold above which the airplane cannot take off at its maximum weight and thus must be weight restricted. The number of summer days necessitating weight restriction has increased since 1980 along with the observed increase in surface temperature. Climate change is projected to increase mean temperatures at all airports and significantly increase the frequency and severity of extreme heat events at some (Scherer and Diffenbaugh 2013; Donat et al. 2013; IPCC 2012). These changes will negatively affect aircraft performance, leading to increased weight restrictions especially at airports with short runways and little room to expand. For a Boeing 737-800 aircraft, we find that the number of weight restriction days between May and September will increase by 50-200% at four major airports in the United States by 2050-2070 under the RCP8.5 emissions scenario (Moss et al. 2010). These performance reductions may have a negative economic effect on the airline industry. Increased weight restrictions have previously been identified as potential impacts of climate change (National Research Council 2008; US Global Change Research Program 2009), but this study is the first to quantify the effect of higher temperatures on commercial aviation. Planning for changes in extreme heat events will help the aviation industry to reduce its vulnerability to this aspect of climate change.
Why did I allow my membership in the AMS to expire? The political silliness had taken total control of my professional society. Publishing this fantasy in the Bulletin is a good example.
John C, I shake my head and ask myself why I spend $100 a year for the aggravation of continuing to support this AMS drivel.
As a professional pilot and experienced meteorologist, I can only sigh and shake my head again at this particular study. Denver, Colorado Springs, Albuquerque, El Paso and SLC (to name a few) already have frequent weight-restricted flights. Weight restrictions apply most frequently to the regional jets and turboprop carriers. 1998 in West Texas and the High Plains was particularly painful to aircrews and passengers as luggage was removed without the knowledge of their owner to meet takeoff weight restrictions on hot, calm days and short runways. In my experience (anecdotally, I don’t have the stats) this has been much less of an issue since then. I don’t think it’s a coincidence that my experience corresponds to the “pause” or cooling since 1998,
From an aeronautical propulsion perspective, the study fails to recognize advances in engine efficiencies that by 2050 will offset much of their warming-based concerns. in 2050, 35 years from now, most of today’s 737-800s will be retired. Mark’s point (below) about Boeing’s engineers is spot on.
I am looking forward to joining the Open Atmospheric Society: http://theoas.org/about/
hifast- Agreed- back in the 90’s I was working as a Co- Pilot on a DC-7 airtanker out of ABQ,SLC etc, We ‘d depart ABQ south or west bound usually, and due to the high, hot, conditions and the fact that the R-3350 radials were ah, sensitive to temp extremes i,e, too hot, too cold, killed them, you did a METO climb very rarely past 500 agl and did a cruise climb at whatever would keep the temps down.
We’d have conversations with departure like this: “Ah do you know your mode C shows you BELOW field elevation?”-as we would dip into the Rio Grande Canyon to cool off and raise the takeoff flaps….
The Salt river drainage was handy at Phoenix too …
Now the next gen is coming on for Airtankers, RJ85’s BE146’s,MD87’s DC10’s
etc. Single engine airtankers or SEATS also..
Models are just that-nothing based on reality. the real world blows on past the model…What I am amazed at is density altitude issues on aircraft performance is treated like something new…
I guess the weight restrictions from warm temperatures means we will never be able to fly to the Sahelian countries, of the Gobi desert in summer. Shame. I was looking forward to the introduction of powered flight to Africa.
I will have to communicate this emerging danger to the Ukrainian pilots in the DRC who routinely take off with 150% overload from the Lubumbashi airport delivering equipment to the mining companies in the triangle.
I agree. It is said that with enough power you could get a brick to fly. But…you still face the expansion of air with higher temperatures which results in thinner air (like at higher altitudes) and less lift. Like in Denver, already at a high altitude, on hot summer days. Lucky that global warming has gone away except in the computer programs used by the IPCC.
Good post, hifast. I’m wondering just why this study was undertaken. I could find nothing in the abstract that wasn’t well understood long before I began flying just over 60 years ago. This forces me to conclude that they’re really getting desperate. Scare stories about the honeybee, the walrus, polar bears, coral, chocolate, glaciers. . . ad nauseam. In this case, they are simply projecting current aeronautical technology into a future that they assure us will be much warmer than today. No allowance for advances in engineering, adaptation (or even global cooling). Seems to me that this study, like many others, was another waste of taxpayer money.
You might be able to find a 737-800 in 2050 but you’ll probably have to find it in a museum somewhere.
JayB the 737 may be in a Museum in 2050, but Dollars to Navy Beans there will be DC-3’s/C47’s still making a living…
So if the hot air expands (uniformly over the whole earth of course) where is it going to go ? Seems like sea level air pressure won’t change much. And the thermal updrafts, should make take offs easier.
I never tried to take off down wind, but I did land down wind once. Talk about a lesson in aeronautics. The distance a piper Colt can travel down wind with zero power is quite astonishing.
Lie I said; I did it once !
I’d guess that by 2050 you’d be more likely to see the 737 MAX-8 than the 737-800 anyway.
Not just the AMS. When I see words “Center for Climate Systems Research”, I expect drivel. I have promoted the Columbia University to a Columbia High – no, Columbia Middle.
Had to be some good Columbian to get that high.
The once very useful Australian CSIRO has also degraded itself into just another CAGW tub-thumper.
Amen! What complete drivel. What will we be flying in 35-55 years? What were we flying 55 years ago? In 1960 the 707 and DC8 were king and queen with their huge capacities of 250,000 lbs maximum takeoff weight powered by four relatively scrawny 15,000 lbs of thrust turbojet engines. Compare to GE and RR motors of today with upwards of 90,000 lbs of thrust lifting takeoff weights over 1 million pounds.
I do remember a seemingly endless takeoff roll in a stretched United DC-8 loaded for a trip to Boston at the old Denver airport in the early 1980s on a hot summer day–we used all of that runway! Density altitude is of course a real consideration.
Oh, and aren’t the models (and the observed warming) more about higher low temperatures than higher high temps?
Shuffles off, muttering and shaking head.
There will be no further technical innovations in aerospace, and no more improvement in aviation propulsion systems. Guess I better start using up all those frequent flier miles ASAP.
brians356.
An interesting model.
You’re modelling on some climate model that has the Arctic ice-free with teeming wildebeest by December 2014, I guess.
One point not mentioned is the average weight of the future flyer.
My model has that at about 430-450 pounds – about 200 kilos – by 2060.
I’m using a GIGO/A5.BotE.guess-18000 model
[BotE – Back of the Envelope]
[18000 – amount of weekly grant I expect for funding from Friday. Sterling, but dollars would do]
Oh – Mods: – /Sarc actually.
I know you didn’t guess! [/Sarc^2]
Auto,
somewhat dischuffed that shysters in high office continue handing out money-pit content to plausible charlatans – and a few honest scientists, who want to but bread on the table.
No worries – we’ll have rechargeable electric airplanes by 2050; no carbon footprint you see.
I agree John, I used to fly for a living back in the 60’s and 70’s and back then there were a few airports round the world that were WAT limited, ie a/c weight, altitude and temperature. Tehran, Nairobi to name but two of the many. Takeoff from these were usually early in the nornings if you wanted a full fual load for the next leg. I cannot believe that any global warming will make the problem worse given that aircraft have operated all round the world with its great variation in temperatures for nearly 100years.
After 30 years I let my AMS membership expire for the same reason.
Did Boeing suddenly stop hiring Engineers?
Did that a while ago. “Last one out of Seattle turn off the lights”.
“…impact of extreme temperatures…
I stopped reading right there.
So they use a modelled output from ridiculous climate models?
Ok, in the modelled future I won’t model my life into an airplane again.
“Ok, in the modelled future I won’t model my life into an airplane again.”
Would that be in a “model” airplane?
I knew, I had forgotten something. 🙂
Hey, any landing you can walk away from is a good landing, as the old pilots used to say.
And no matter how gruesome the sight, I always walk away from my rc model’s “landing”.
Am I the only person who thinks this is utter bull sh*t? How do planes function at the equator where it is hot all the time? How did the Japanese and Americans ever manage to fight an air war in the Pacific islands during World War II? You just work around temperature, air density, and altitude restrictions, and if there is an economic effect, it is probably very little. If it costs more, how is that any different from what carbon taxes would add to the cost?
It’s not COMPLETE bullshit. Hot air is a bit thinner than colder air. But neither is it high quality work. Notice the lack of numbers? And the author’s apparent ignorance of the fact that warming seems mostly to affect Winter and night time temperatures, not afternoon high temps.
If you want to entertain yourself for a few hours or days, the math is available at http://en.wikipedia.org/wiki/Density_altitude#Calculation.
But even if the assumptions were correct — which they probably aren’t remotely, the impact would be that a few aircraft requiring a lot of runway at a few airports without a lot of runway — might have to fly with a few empty seats or a bit less fuel on a few really hot days. (FWIW, a 10 degree F increase in air temp is roughly the equivalent of using an airport 500 feet higher. e.g. Buffalo, NY vs JFK)
If the average temperature did get higher, the airports could also add a few feet to their runways to compensate.
So how much does the 0.79 degrees of warming effect the take-off length, 1 foot maybe a foot and a half
No Don the planes just sit on the runway till the temperature drops. Never fly empty… weather related you know.
I was wondering that – I was at the Phoenix Airport last summer when it was 115 degrees F, probably at least 120 out there on the concrete and asphalt runway, and I swear that I saw a long line of planes taking off, almost like they had been designed to meet just such a challenge. Maybe I was dreaming.
That can’t be true.
My model says so.
/sarc off
Sky Harbor Airport (Phoenix) did suspend takeoffs and landings for a few hours on a couple of days in June 1990 while the official temperature exceeded 120°F. I seem to recall it had something to do with some set of flight parameters were not available for temps beyond 120°.
That problem was subsequently remedied, but the Phoenix temperature has never exceeded 120°F. since.
By 2050, most aircraft now flying will be scrap. New models can have the relevant design features – bigger flaps, better braking systems, higher-rated engines designed for faster acceleration at low air speeds, more efficient engines requiring less fuel, hence a lower TOW. built in to cope with the change – if any – in airfield conditions. Another non-problem built out of FUD.
BTW. Now you’ve got your bionic ears, Anthony, have you given any thoughts to re-qualifying, just because you can?
“New models can have the relevant design features – bigger flaps…”
Or better flaps
http://www.businessweek.com/articles/2014-11-20/flexsyss-wing-flaps-promise-to-save-fuel
Well before 2050 aircraft will be significantly different. Fuel costs are the largest single operating expense of many airlines, topping 40% in some cases and 30% or above in many others (). More efficient engines and lighter airframes are already huge priorities at Boeing, and I assume Airbus as well. Using less fuel per passenger mile means making the same trip with the same manifest needing less fuel on board, which means lighter takeoff weight.
Airlines and aircraft manufacturers have to make progress on this front to stay competitive and keep air travel affordable, and the improvements already rolling out in current production will more than equal the trivial air density reduction from higher temperatures. “Climate change” considerations will make no difference to their efforts although likely PR departments will trumpet such nonsense loudly.
On the other hand, the increasing obesity in the US population, if it spreads worldwide will swamp these efficiency improvements and then some. I wonder if anyone has modeled that?
There should have been this link included in the above: http://www.aviationdb.com/Aviation/FuelExpenseByCarrier.shtm
In the late 19th century there was great gnashing of teeth and wailing over the horse manure problem in London and New York. So much so that an international conference was held in New York. People at the time just could not think what the solution was going to be. I think by 2050 we would have solved any take-off problems.
http://www.techfresh.net/wp-content/uploads/2006/12/sax-40.jpg
http://a.abcnews.com/images/Travel/ht_whale_plane_4_sr_140117_16x9_608.jpg
http://4.bp.blogspot.com/-9Ku3aTbj0Mc/VE5VTwINHGI/AAAAAAAAkME/xaYyr5qfblI/s1600/q.png
Why do future planes look more and more like fishes?
Contrari – I was thinking birds because of the wing shapes, but yeah, fishes. Good thought.
At high MPH the air acts as if it were a liquid.
Fish have evolved their shapes to move fast through a fluid. Aircraft have the same problem and the shapes will be much the same.
ConTrari
November 26, 2014 at 8:53 am
“Why do future planes look more and more like fishes?”
Why do current planes all look like tubes? Because that’s simple to build.
Blimey – a plane powered by LNG!
Auto
Is it just me, or does that second picture look like a Romulan war bird?
Rather like a Klingon Bird of Prey. 😉
I would not want to sit too far off the centerline of either of those ultra-widebody designs, nor any others!
I was going to mention the same thing – maybe the turning circle is measured in hundreds of miles in order to avoid having flying passengers inside a flying plane.
I think the manure problem we have now is even worse – CAGW and politician manure…
I discovered over at Bishop Hill :
“… in order to reach its outlandish picture of the future, RCP8.5 is forced to make some outlandish assumptions, most notoriously that the efficacy of carbon sinks will decline over time, despite the literature not actually supporting such a case. There are also some wild assumptions about energy use and population growth that have been documented elsewhere.”
http://bishophill.squarespace.com/blog/2014/11/27/a-right-royal-contradiction.html
I know of a private pilot who got into trouble trying to take off from a mountain airstrip on a hot day. He stalled it and came down hard. End of license.
I know of a private pilot who got his licence pulled for landing twice while forgetting to put down his landing gear. Some people have got a whole lot more money than sense.
I hate to tell you this, but private pilots are not all that well trained.
I beg your pardon! 59 years as a private pilot. 0 accidents. Common sense rules the day.
Agreed, 3 major crashes recently hitting my local news involving private pilots – local whole family killed when pilot lost bearings in a storm and crashed, local 4 men killed when float plane stalled on landing – plane was overweight as contributing factor, 2 men killed when pilot lost bearings in a storm. Sorry, I won’t fly on a small plane with a private pilot.
Speak for yourself. They get a darn side more training than the people we let drive automobiles.
We test drivers to make sure they signal before turning left or right. They are never tested for ability to turn left or right, and that is quite evident at any intersection.
Neither are those fledglings leaving the nest the first time.
The survival instinct kicks in strong though, and usually gets one thru the early stages.
It did for me.
Well-trained private pilots don’t all demonstrate good judgement.
40 years, 2 bird strikes on takeoff, both acts of God according to ATC witnesses, very glad no Center for Biological Diversity witnesses.
Either below minimum airspeed or AGW: run it by the folks at Columbia. I’m surprised the FAA would pull a ticket for it, though.
How many flights worldwide are delayed today due this phenomenon?
The physics seems logical. But are we so close that it will become a real problem?
Some days are quite hot in some places, even now.
Back in the 80’s I was on a plane out of Madrid. We had to wait for space on a longer runway because it was too hot to take off on the runway we had been originally scheduled for.
Back in the 70’s they stopped doing commercial flights out a small town in central BC because it often got too hot for the length of the runway and no one wanted to cut off an access road to make it longer. One of those little valleys where the temperature was frequently over 100 and trailer jacks often sank through the asphalt … Hard to make an asphalt mix that is good for -30 to +100.
Elevation (AMSL) of the runway surface is a larger effect. Whatr they gonna do ’bout that?
Since we’re told that sea levels are increasing at an ever alarming rate. Soon all airports will be engulfed by the rising waters, and have to move to higher and higher ground, further compounding the AMSL issue.
Yikes, truly is worse than we thought… wait, wouldn’t rising seas make the AMSL issue better?
This is when sea planes will come in handy.
Thanks for making my brain hurt (it doesn’t take much).
doesn’t rising sea level improve the takeoff conditions, by lowering the altitude of all airports? thus global warming is the solution to its own problem.
But if the sea level rises, all existing runways will be by definition, at a lower elevation relative to sea level. 🙂
Along this demented line of “modeling” sea level rise thinking pretty soon they will be in a panic about having to repaint/adjust waterlines on all the boat and ships in the world.
I would think a secure and inexpensive source of quality fossil fuels to actually run the jets would be more of a concern in 2070. Anybody ever land or takeoff from Lima Peru?
Try Quito, Ecuador. At approximately 7900 ft, the air is thin. If the planes can take off and land there, why should they have a problem elsewhere?
I recall flying back from Johannesburg to NY, which was fairly hot and about 5,500′ above sea level. The outbound flight had been non-stop but the return required a stop at the Cape Verde islands to reload more fuel since the maximum takeoff weight meant that we couldn’t take on a full load of fuel (it was a 747 as I recall).
Yes, I did several times and I will next Saturday actually. May I ask why?
Bogotá airport is 2600 m.a.s.l.. Lima’s Jorge Chavez is near sea level
Addis Ababa, Ethiopia 2440 metres, approx 8000 feet.
Went out of Ngari Gunsa (Ali County) airport in Tibet last year
Elevation 4273m and the half-loaded 737 took all 4700m of the runway
No problems – doesn’t ever get above 10 deg C there
I live in sight distance of a major wildfire refueling/reloading base at an altitude of 4800 feet. Watching a fully loaded air-tanker take off and do a slow climb-out on a 100° F (38° C) day is almost painful. I also monitor their radio transmissions. I have yet to hear a pilot request a partial load of either fuel or slurry due to density altitude. They use a bit more runway and don’t climb as quickly but get off the ground without a problem.
I have also left that same airport on regional commuter aircraft and heard the announcement that the airline would be awarding free miles to anyone who could wait for a later flight due to load restrictions on a hot day. I think the words here are what most “skeptics” have been trying to tell the alarmists for years “humans and nature adapt to conditions”.
And the very next article on my RSS : http://en.itar-tass.com/russia/763774 Siberian airliner passengers help push icebound jet to runway
I thought that was bad news to push, pull, or step on control surfaces?
I thought I read that Siberia was warming? The story said it was -52C on the ground, it’s not much colder than that at altitude?
Why would we need to adapt when we know that temperatures will be the same or lower than they are today?
FAR part 121 carriers operate under much more stringent rules in these areas.
its also good proof of why these reporting stations at airports cannot be used for climate models.
they deal with tarmac/runway temps as the FDC on aircraft need that temp to feed to FADEC for thurst adjustments.
used to work for business express then (buy out) amr-eagle at kbgr, our old a model saab 340 (turbo prop ge ct7-5a engine) were really bad in hot weather. the SF340b model (ct7-9b engine) and then the embraer 135/140/145 were not as bad.
Ding, Ding, Ding!!!! We have a winner. The airport temperature stations are sited to give accurate data to pilots for air density takeoff calculations. They succeed when they either accurately reflect the air temperature over the runway, or slightly overestimate it. Nobody will died if you calculate your takeoff conditions with a higher than actual air temperature. But these same stations should be very suspect for use in climatic measurements. As airports are expanded and runways widened, the temperatures will go up in ways that have nothing to do with climate, and everything to do with microclimate.
As a weather observer in Canada who has worked at a few different airports and used to preflight brief pilots, i can tell you with near certainty you will not find a metar who’s temp is anything but ambiant temp over a grass area away from pavement. Perhaps some airports put runway surface temps on the ATIS but none that I know of. It sounds like it would be good data to have available though.
The desperation is getting more and more hilarious. How stupid can it get?
Please don’t ask that question. I really don’t want to see the answer.
He made it sound like a challenge, didn’t he?
The sky is the limit… or so I thought.
Einstein postulated that there is plenty more.
Why would meteorologists care about calculations done by thousands of pilots every day? If it was a problem for the airline industry you’d expect the paper to come from them.
Here’s another thing they could worry about: higher density altitude wrecks the single engine performance of light twin-engine aircraft. This could lead to more off-airport landings – much more scary than restricting take-off weights. Cue paper.
The ‘Alarminati’ at work.
Ok. I guess Lima is not that high, but there are plenty of functioning commercial airports at over 2000 metres…
There are plenty:
http://en.wikipedia.org/wiki/List_of_highest_commercial_airports
Winner is Daocheng Yading Airport, China at 4,411 m (14,472 ft). I always thought La Paz was the highest airport at 4,061 m (13,323 ft), but China has four higher than that. The Wikipedia page claims their list (28 commercial airports higher than 2,500 m) is incomplete, so I guess there are more. Twelve are in China, one in India and the rest in South America.
Echoing Matthew W further down, this airport list just confirms that climate change will hit developing countries hardest.
(/sarc, if anyone needs it).
Per the peerless Wikipedia [so accurate that I can edit it . . . .]: –
Mexico City International Airport. Latin America’s busiest airport by traffic movements, has an Elevation AMSL of 7,316 feet / 2,230 m
At Dry Adiabatic Lapse Rate, that is about 20C cooler than a Virtual sea-level MEX.
And I remain much more scared of the cold than the putative 0.8C of heat that we will all get – per some good folk – by twenty whenever [after they have retired is that? Possibly, I don’t know their circumstances].
Auto.
Not being a scientist, can some one explain to me what exactly is 200% ?
When I learned basic maths at primary school percentages were expressed in one hundreds.
I hope these climate “scientists” are not designing aircraft.
Many people throw around percentages in a misleading fashion, I find it easier to think of it in terms of the the fractions: 50% is 1/2; 100% is 1/1, and 200% is 2/1.
for discussing increases to an original amount:
an Increase of 50% means you have your original amount, plus 1/2 again, for a total of 1.5 times the original. an increase of 100% means you have the original amount, plus an amount equal to that, so that you end up with two times what you started with.. An increase of 200% means you have your original amount, plus an amount equal to twice that amount, so you end up with 3 times your original amount.
You can see how that can quickly get counter-intuitive if you’re not careful, which is why people who want to slant things find it so easy to muddy the waters by using unexamined percentages instead of actual numbers.
My guess is, to some people an increase of 200% sounds like a whole lot more than 3 times as many.
Without knowing how many weight restriction days they are currently having and the full impact of a weight restriction day I don’t know how to advise them…If they were looking for my advice.
“evil always takes advantage of ambiguity”
GK Chesterton
Say there are 20 load restriction days (LRDs) per year and you predict a 50%, 100% and eventual 200% increase in LRDs over the starting year in the coming years. Say also that in the following year LRDs go from 20 to 30. That is a 50% increase over the start year or 100*(30-20)/20 as in 100 times (this year – start year)/start year expressed in percent. The next year it goes to 40. That is a 100% increase over the start year or 100*(40-20)/20. At 60 days it is a 200% increase or 100*(60-20)/20.
At least they didn’t express the result in equivalent Hiroshima atomic bombs of heat.
Hot, High and Humid…that’s the mantra for determining whether to take off or not. Here in Colorado, humidity isn’t such a problem but hot and high are. Each summer, there are several accidents because of density altitude stalls. Of course in the winter we have the problem of icing with similar results. Humm, maybe with “””climate change”””” we won’t experience planes augering in because of icing in the winter.
(and if you need a >>>sarc<<<< tag there it is.
Mike
Early 70’s, Stapleford airport, 707, very hot day — our takeoff run went on and on and on at which point I was thinking OOH Crap, then we hit a dip in the runway which seemed to launch us off.
So how many flights have been aborted because of global warming? How many flights need to be fueled to maximum weight that must takeoff from high altitude airports in the heat of the hotest days? It is probably less than the number of people who have lost their lives climbing Mt. Everest.
More what-if scenarios based on a faux-science fantasy? How refreshing.
Because jets are taking off with no runway to spare? How desperate for a publication can they be? That’s the real scientific curiosity here.
Anyone see the Boeing Dream Liner land at the small private airport in Wichita last year by mistake? It took off on that runway, one of half the desired length.
Empty, no doubt, with minimum fuel. –AGF
They stripped out all the seats and interior furnishings. No passengers or luggage, and just enough fuel to make it to the correct airport which was just 5 minutes away.
35 minutes worth then – 5 minutes plus the legal VFR reserve.
Being light means both higher acceleration and lower take off speed.
Actually it was a modified 747 freighter, used to carry 787 parts, known as a “Dreamlifter”.
Soon after a similar thing happened to a passenger 737.
Obviously they’re referring to model planes trying to take off in the model climate, real planes in the real climate will not be affected.
Or they’ve been sniffing model glue.
How about we just model the planes are filled with nanotube conductors instead of copper wires and save 2 tons of weight.
Antoinette points out that most of aerospace industry still uses pure copper wire for its conductors — virtually the same copper wire used since the 1850s. His company’s nanotubes could replace this material with better conducting nanotubes, which weigh a mere 20 percent as a much as the copper wiring per volume. Antoinette adds, “Copper wire is still the conductor of all our satellites, all our aircraft.” He points out that a current 747 jet has two tons of copper wire aboard — a weight cost that could be cut in half by the use of nanotubes. He says, “you’re talking literally millions of dollars of savings in fuel costs over the life of an airplane.” – See more at: http://www.dailytech.com/Sheets+of+Cheap+Carbon+Nanotubes+Now+a+Reality/article10927.htm#sthash.HAJzWtVN.dpuf
The newer generation Airbus aircraft and the Boeing 787 actually use aluminum for their power cables to achieve significant savings in weight.
[emphasis mine]
I do not see them saying the observed increases in surface temperatures caused any problems, just that their “observations” were temporally equal. UHI anyone?
Pilots, what regulations changed in this time frame? Standard flight procedures? I haven’t read the paper but I’d like to know why the restrictions were in place along with the factors that went into the decision. Fuel costs shot up dramatically in this time frame thanks to our pal Jimmy Carter. Since it takes more fuel to get to Vr and maintain a safe V2 in higher temperatures, and the greatest fuel use is at take off, I can imagine a closer look at the economics after the “arbitrary” date of 1980… regardless of an airport’s “climate change.”
Add two feet to the runways every year and they should be OK. –AGF
agfosterjr
November 26, 2014 at 8:18 am
You are right, of course, but the [wait while I am thinking of an elegant way to say something a tad uncomplimentary] – ahhh – carbonistas will politely suggest that the extra two feet will need to be manufactured or excavated – and then trucked, at most [Non-adjacent to the sea, nor rail connected] fields. And then, laid to last . . . .
Oh dear.
All those plant foods emitted.
But surely – mitigation and adaptation are our guiding lights. As you rightly imply.
Mods – it’s me.
/SARC [I think I have other modes, but the ‘S’ one does pop up, mmm, from time to time. When near a keyboard, say!]
Auto
In the stark light of reality, why?
Using RCP 8.5 is a bit ludicrous. That pathway assumes that several times more coal is burnt, than is in reserves.
Les, I agree with you that using 8.5 is absurd. I used to think so for the very reason that you gave. However, I discovered that I had been mislead by our Green friends behind ‘the Club of Rome’. Official reserves are a small fraction of the amount of resource available. Resources are what’s there. Official reserves are defined by regulation and law, and include assessment of economic feasability of recovery. (This distinction was specifically not made in that alarmist tome.) That assessment changes with every technological advance. Reserves are less than one twentieth of resources. So there’s no problem with burning more fossil fuel than we have in reserves- we’ve already done that several times over.
The reason I see using 8.5 as absurd is that it’s at the alarmists high end, unlikely even in their view. And thats not taking into account the ever increasing evidence for a much lower climate sensitivity.
Good Lord! I had a PPL long ago and gave up when my hearing went. I nearly lost it at Windhoek airport one hot sunny day. I was flying solo in a Cherokee 140 and about to depart for Cape Town when the tower asked me to use the short runway. No problem and off I went. I did have full fuel tanks. The end of the runway was fast approaching and I couldn’t lift off. I remember my instructor, Ernst Stogmuller, who had demonstrated a short take off once. Nothing for it. Full flaps and the little Cherokee jumped into the air. Keep the nose down and EASE OFF the flaps as speed increased and I cleared the earth bank at the end of the runway. Phew!
Do we really need to read this crap? The nearby Aspen airport at 7800 feet altitude has a day or two every few years where it is too hot for airplanes to take off. Considering the lapse rate, 3.5°F/1000ft, sea level cities would have to warm some 27°F above current nominal temperatures to have an equivalent effect. It ain’t gonna happen.
I can’t help but laugh at the feigned concern for the profits of airline companies. Every proposal to ‘fight global warming’ has far worse impacts on the economics than the ‘problem’ does. They offer amputation at the neck as a headache cure.
So what is the rcp 8.5 emissions scenario?
http://en.m.wikipedia.org/wiki/Representative_Concentration_Pathways
It’s the IPCC worst-case emissions scenario. 8 and a half watts per square meter energy increase. Not very likely even under the believer’s assessments.
So- amputation at the neck to cure an improbable risk of a headache. Sounds legit.
These exponentially calculated emissions increases remind me that Ray Kurzweil’s exponential growth of technology forecasts have us in the Singularity by the timeframe of this ‘problem’. http://en.m.wikipedia.org/wiki/Predictions_made_by_Ray_Kurzweil
Reality and virtual reality will be virtually indistinguishable by then, undoubtedly changing the airline industry so unforeseeably that this forecast will seem absurd. Something like a pre-telephone calculation of ever-increasing numbers of telegraph delivery boys being needed by 2014.
An important thing to note is that Kurzweil’s predictions have proved far more accurate than the IPCC’s.
Didn’t the obesity crisis start around 1980? In the future only skinny people will know what flying is. 🙂
Of course if the oceans started to melt as fast as the models claim they should, then the height above sea level for all of these airports will be reduced which will result in the air at those airports getting thicker.
Oops, I meant glaciers melting, causing the oceans to rise.
My bad.
Two Canadian pilots coming in to land at an airport, think the runway is very short, so they do a flyover. It is short, so they plan the landing, knowing they have very little marging for error.
They come in just above stall speed, with full flaps, and apply emergncy braking. They come to a halt in the grass just at the end of the runway.
Pilot – “That is the shortest runaway I have ever seen!”
co-pilot – “yeah, it is. But look how wide it is. It must be 2 miles wide!”
I’m not sure if this is making fun of Canadians or marvelling at their landing skills. We do certainly know how to Take Off, Eh also!
Thanks – I definately needed the eye-tearing chuckle this morning
Magnetic anomaly?
Its articles like this that cause me to doubt Global Warming. This is a pointless study to booster the case for global warming solutions. If they exaggerate in this article, how many other areas are they exaggerating? They assume that the Engineers at Boeing will do nothing to accommodate lower atmospheric densities. If there is warming airplanes will be redesigned to accommodate the warming and runways will be lengthened. If this study came from Boeing or Airbus it would carry some weight.
“The number of summer days necessitating weight restriction has increased since 1980 along with the observed increase in surface temperature. …………………….
……….These performance reductions may have a negative economic effect on the airline industry. ”
——-
Ok, fair enough……These guys trying a point out the probable negative impact-effect on the airline industry due to performance reduction because of an Agw projected by an IPCC model……fair thus far……..but if anyone can help with information about the winter days necessitating airport closures because of heavy snowing and frost as being increased or decreased since the 1980 in comparison to the summers days necessitating weight restriction and the probable negative effect in comparision in the both cases…….. that I think will be a better picture of what already happening, probably!
Increased airport closures due to cold and snow in winter may already have a much higher negative effect on the airline industry then in case of summer days…….or maybe not!
maybe someone may help with such an information…….!
cheers
Thunderstorms are probably the most disruptive weather factor for the airline industry in the US.
Aren’t they affected by global warming? The authors tackled the wrong problem! They should have gone for increased thunderstorm activity and the lengthy ground stops on some out of the way part of the airport that usually ensue.
Are thunderstorms actually increasing in either numbers or severity or both?
Who knows? For the purposes of climate science, it doesn’t really matter, does it?
msg,
BL:
For ‘Climate Science’ as practised by some, I agree that it truly doesn’t matter.
Is the grant money still coming in?
Then – more of the same.
I’m sure many climate scientists do seek the truth [as each individual sees it . . . . ] but there seem to be some who are, oh, carbonistas, shall we say?
Auto
I don’t dislike this report that much. They say the airline industry needs to plan for changes. I can’t argue against that, but it would be helpful to have a realistic idea of what the changes are going to be, and the climate models we have don’t come close to doing that.
I think is is very silly to be talking about 737-800s as if it they will be still around in 2050.
Unfortunately it will. It is to be called the 737 Max, and apart from new engines, it is much the same as the 737-800. Please see my longer post below.
R
notice how they use the anomalously cold period ending in 1980 as their comparison period
Actually then there is this. http://www.dailymail.co.uk/travel/travel_news/article-2850110/Passengers-told-PUSH-plane-brakes-froze-minus-52C-temperatures-Russia.html?ito=social-twitter_mailonline
Sadly this is another example of just how the academia jamboree continues.
They sit around just thinking stuff up, apply for a grant to fund themselves for the next two or three years and then produce drivel to justify what they have been up to.
From the academic’s point of view it’s all fair game and until and unless somebody is brave enough to put a stop to it, it will go on and on. I cannot believe most of these guys actually believe what they are producing – it’s just too bizarre.
To be fair, with the open hostility to anything moving anywhere south of panic, who in their right mind would do anything different?
There is a big mountain to climb and it needs somebody with big boots to make the climb easier.
Totally crazy articles like from organizations like the Department of Earth and Environmental Sciences, Columbia University, New York, are a dire reminder that all of humanity now has become the subject of an evil doctrine comparable with the NAZI Regime that wouldn#t have existed without it´s propaganda program.
There is only one difference.
We´re all Jews now.
Sorry.
Not NAZI.
They, the NAZIs, were very B A D – as I think everyone agrees.
Our Climateers [our Carbonistas] are certainly misguided.
I think some are greedy [for money, tenure, status, publicity, sexual partners, pleasant foreign travel to conferences in agreeable locations, and the rest. Individual motivations need to be left to the individual.]
I agree that they have a propaganda arm [like most major league sports companies (etc.), if with different aims].
But – they are not NAZIs.
A handful may be unpleasant – ‘watermelons’, a term I’ve used before, but – I repeat, n fact, I insist:
They are not NAZIs.
Please check what Hitler’s NAZIs did.
Executed some millions (6 million is the best estimate I have seen] because they were the wrong: race; sexuality; or religion – an awful lot of Jews were killed, for example, most of the 6 million or so, simply because they were Jewish.
Plus:
A World War that killed 50-60 million [about the ‘present’ population of the UK], and about 2% of – the t h e n – global population, and affected a billion, or more.
And led to the development of computers at Bletchley Park, and atomic bombs.
The long term consequences of our Carbonistas’, our fellow humans’, desires, and if taken to a [maybe not their] logical conclusion, is a huge [75% or 90%, 95% possibly] cut in global human populations.
You?
Me?
Our families, friends?
How might this affect the global communication and global trade that we rely on?
Could it be back to the comms and economics of he700s, when Charlemagne ruled, or Offa (of the dyke)?
At the higher end – seeking a global population in the low-to-mid hundreds of millions – they will see a lot of folk die alone – no children, no partner . . . .
A horrible conclusion. I think, anyway.
Auto
Right. Worry about hot temps, but snow/ice isn’t an issue, like today in the east US. Same ‘ol model-flup.
i’m going to be traveling on one of these-
http://www.dailymail.co.uk/news/article-2416809/Return-zeppelin-Firm-unveils-gigantic-airship-revolutionise-goods-carried-world.html
Surely, this is good news for the Hot Air fanatics, as the reduced number of flights will cut CO2 “pollution”. QED!
Think of it this way: airlines might have to take some weight out of their planes by, you know, spacing the seats out a bit further.
I’d say that’d be a good thing, if fuel prices fell enough that they could make money flying like that…
😉
In fact, I wonder if there’s a grant in the great climate-science slop pit for a paper on The Impact Of Global Warming On Airline Seat Pitch.
They can not predict the weather 30 days out but can tell us all about “extreme weather” years from now caused by some trace gas that has not had an effect for almost 20 years now.
Terrific. You tax dollars at work.
Did they ask anyone in the commercial aircraft industry? Apparently not. How do they think commercial jets have been taking off from Lima, Peru, for the past 50 years? When I worked at Pratt & Whitney Aircraft (they build jet engines for those that don’t know) back in the late ’60’s, it was routine to use water injection in the engine when extra power was needed for hot days or high altitude.
Apparently these studies are funded because the Obama administration has directed all branches of the government to prepare for global warming. And college professors have to bring in “research” dollar to keep their jobs.
Oh dear… we haven’t even fully figured out how lift is generated… maybe, if we manage to do that in the next 50 years, we can deal with a slight increase in global temperature?
Is there anything that ol’ devil CO2 won’t make worse?
Just wait and see! For anyone that believes there’s no conspiracy going on….do you really believe this kind of tripe would be published without a motive other than CAGW?
Tripe.
Important subject.
MarkI –
Global warming will slim our pigs, so trimming the volume of our porcine tripe, and perhaps the flavour, unless taken with watermelon!
{I am not sure if this applies to politicians at the trough . . . }
Make runways from reflective material instead of the black absorbing stuff OR travel in winter
They can shovel all they want … these studies all have that same distinctive aroma …
http://tianatozer.files.wordpress.com/2013/01/shoveling-shit.jpg
16R at SLC is 12000 feet long, and the surface is a white-gray concrete. We once got a Beech King airborne off of it in mid August, at 30% throttle, and still had a good 7 miles of flat desert ahead of us. (we did have clearance from ATC to use the entire runway as part of a training exercise). If you can’t get airborne off that patch of ground then you should just park the plane and walk to your destination
I hate to be a party pooper on the hatin’ going on above, but this is actually one of the few things I’ve seen referenced here that makes sense if one allows that jet technology and design is flat and that all other things in the climate are equal. It is, in fact, more probable that it will be warmer in 2050 than today as opposed to cooler because CO_2 is, in fact, a greenhouse gas and it is, in fact, strictly more likely that an increase will lead to a positive temperature bias relative to any temperature that might otherwise have held then (although in a chaotic system with natural variation and feedbacks of largely unknown and unpredictable character the expectation value of the bias and its comparative size relative to the probable scale of the “noise” of unpredictable variation is difficult to estimate). It is also worthy of note that one has to weight the result with the probability of RCP8.5. This is basically a direct extrapolation of CO_2 increase rates assuming no change whatsoever in the scaling of its growth all the way through 2050, hence it assumes that fossil fuel costs remain flat relative to competing technologies and fuel sources, it most definitely assumes that we don’t develop either fusion or significant PV solar resources in the meantime, it assumes no development of LFTR or improvements or deployments of uranium fission based power. If one considers e.g. RCP6.0 or less to be more plausible on this timescale, one has to further adjust the Bayesian weight accorded to the conclusions accordingly.
(the probable number of new infections generated per existing infection) greater than 1, ideally much greater than 1, and just the right ratio of incubation time to first appearance of symptoms and death.
Still, given these caveats the reasoning and conclusion seem sound. Sure, one can very likely take existing data on days with temperatures or other conditions leading to weight restrictions per airport, make a reasonable assumption regarding the increase in the number of such days, and publish it.
One is free to wonder what weight should be given to the unstated Bayesian priors attached to the estimate. Then one is equally free to ask — at what point does publishing speculations of this sort stop being “science” or even a practical part of planning for the future and start being politics?
For example: Could I reasonably publish a report entitled “Probable effects of a gamma ray burst on the price of wheat in Nebraska”? How about “Estimating the likely extinction rate of North American species that would result from a 1 kilometer asteroid impacting in the mid-Pacific”? I think not, because we have no reasonable way of estimating the prior probability of either a gamma ray burst or 1 kilometer asteroid collision, outside of concluding on the basis of the observational fact that they are pretty damn rare, so rare that the conclusions of these studies would be little more than science fiction, of no practical use whatsoever.
A study entitled “The likely epidemiology of a mutated Ebola virus”, on the other hand, seems more difficult to judge. On the one hand, it is something of great interest, as some mutations might well make Ebola into a global pandemic capable of wiping out half of the human species. Even though these mutations are probably also rare, they aren’t as rare as gamma ray bursts of a magnitude capable of killing off Earth species, especially when integrated over not just Ebola but all viruses capable of causing such a pandemic including the flu, SARS, etc. The information might be useful even if Ebola per se doesn’t ever so mutate. However, the use of the word likely in the title is suspect. How can we even begin to compute the likely trajectories or impacts of all possible mutations of the Ebola virus, and integrate out a weighted probability distribution of probable outcomes independent of probable responses by the medical and scientific community, outcomes that might well be altered by the publication of the paper itself? The title (and very likely the paper) oversimplifies things to the point where once again the paper is almost certainly going to be the journal equivalent of Frank Slaughter’s lovely book:
http://www.amazon.com/Epidemic-Frank-G-Slaughter/dp/0090621611/
Could plague make a comeback and wipe out much of America? Well sure! All that is required is just the right mutation, a medical/scientific community that is slow to react, and
Note well that I know this because I’ve studied statistical epidemiology for one brief interval twenty-odd years ago when my wife was an Infectious Disease fellow, and wrote an actual numerical simulation of the process as a Markov chain. Way cool stuff and definitely worth publishing because it is generically useful. It applies to any mutation of a potentially lethal biological agent.
If HIV, for example, had been spread by mosquito bites or casual contact — sneezing in a room — so that the probability of transmission from one human to another given any contact at all was high, it would have wiped out most of the human species. In all other respects it was a perfect pandemic agent — a very long interval when an infected person was nominally infectious but otherwise asymptomatic, and pretty much a 100% kill rate months to years after infection. Only people with some sort of natural immunity or people in isolated communities who defended their isolation with extreme prejudice would have survived, and if there were an animal reservoir they wouldn’t have survived. I could write a gangbusters novel about this even today, and it would be good because it could still happen! All it takes is just the right mutation, if not of HIV than of some other currently innocuous or self-limiting infection.
But is this science? The statistics and modelling yes. The extrapolation of model results, especially unaccompanied by any disclaimer of the essentially unknown and uncomputable prior probability of the many, many assumptions keyed to any particular claims of outcomes? I’d have to rank that as science fiction.
The top article is right on the edge between. It’s a good idea to plan for the future and make suitable investments. If I were running and airline, I’d want to know this as it might well affect my decisions concerning the optimal airplane design for future purchases, decisions that could lead my company to bankruptcy if I make them poorly. On the other hand, I’d feel very frustrated in not being able to assign a useful expectation value to the probable costs, because I have literally no way to reasonably estimate the probability of RCP8.5. So, useful planning guide? Political scaremongering? Science fiction? You decide.
rgb
A very reasonable factor that was left out of the prognostication is that of miniaturization and substitution of lighter materials (when hasn’t this been happening?). People’s baggage, computers, materials are getting lighter and smaller. Maybe people will all be slim and in good shape. Probably dinner trays on board could be half their weight and the entertainment system, and…. Perhaps a graphene-skinned plane should be considered possible by 2050 – 2070. You couldn’t even fly the computers that were used for relatively simple tasks 30-40 years ago. By 2050, we will probably be able to roll up our computers in film form, with our files in the ether waiting for us when we get to our destination.
It would have been a much higher quality study if it had estimated how much lighter we and our baggage would likely have to be to maintain performance given a range of realistic temperatures – probably no big problem at all. With due deference to rgb’s points, it is a how.- much-manure type article.
Yes, but Americans are getting bigger and fatter.
What hatin’? Pointing out all the flaws in this study isn’t hate. Neither is ridicule, providing the ridicule doesn’t turn into ad hominem attacks on the researchers themselves.
This is our tax dollars at work. In case you missed the sarcasm, I mean the exact opposite. As an American taxpayer I am allow to point out the waste of time, money and other countless resources. As a thinking person in a mostly-free country, I have the right to point out the problems with the study.
Oh, for Gawd’s sake. Even if the technology stays stagnant, they can put bigger engines on.
Seriously?
In mining exploration and development during the late 60s early 70s in Yukon, 3 airstrips. IIRC, were bulldozed on the crests low ridge in the Dawson Range (a lot of traffic of personnel, supplies and equipment). It was exciting taking off into a southerly wind in a DC3 because the strip sloped noticeably downward and after takeoff, you continued to lose a bit of altitude over the bogs at the end of the ridge before gaining altitude. Going north you had the advantage when landing of slowing quickly climbing up the strip, but taking off, you were lugging into the air. There were no accidents in two seasons of their operation. Helicopters were stationed at each strip (Uranus, Neptune and Pluto) for onward ferrying of personnel and small equipment, drill steel etc. The heli pilot at Uranus got tired of people asking how’s Uranus!
Were there skid marks on the other runways too or just on Uranus?
I’ll get my hat…
Hummm, most weather models did not even pick up the snow storm for the NE until a couple days ago, and these models are going to predict this type of stuff 50 years out? LOL
I think Weathebell was the only one who got the current storm right in advance. Thankfully we still have a few knowledgable humans doing some work out there 🙂
I remember a few years ago, some airlines whining to the FAA about (I think it was Denver) where their 737’s could not take off due to the heat, but those airlines running A320’s were having no problem at all. they wanted the FAA to “level the playing field” and stop the Airbus aircraft flying too!
Catapults and catch wires are what’s needed.
JATOs
We seem to do OK with the altitude and temperatures at the Las Vegas airport (McCarran International). The solution to this imaginary problem is simple — build a longer runway. Also, reduce the take-off weight of the flight. There are many other possible solutions. Perhaps in this imaginary future aviation technology doesn’t advance.
That’s because the long runway is 14,512 feet long. Even the short runway is 8,988 feet long. Both of them are wide enough for Canadians to land on (see above).
Lesson – we have amazing adaptability. Simple solutions:
1) Weigh ALL passengers and luggage and adjust as necessary – as done since DC3 days.
2) Reschedule flights to avoid the 1-3 PM and depart during cooler times of day.
How long before some smart a**e applies the same worries to our little feathered friends?
Some hill tops could be devoid of birdsong in the Summer, you know.
Eagle broods will suffer because of their parents inability to lift fish out of the water.
Tell that to the larks flying over the Yourkshire Dales on a hot day singing their little hearts out!
This study at least proves why there was less air travel during the Medieval Warm Period
+10
.. and the fact there was less air travel during the MWP proves it was both real and world-wide.
That’s my post-prandial stomach-settler all over the keyboard. Waste of a good malt.
Larger airports, more concrete, more UHI.
Doubt there will be an issue with crop dusters taking off from grass fields in the country.
Which idiot approved the funding for this garbage?
The whole CAGW movement are starting to reveal more and more the fiscally and socially irresponsible idiots that they are. I was also a private pilot and as stated by experienced commercial jockeys above weight calculations for density altitude have always been and always will be a part of aviation.
Desperation me thinks.
Could this be the same model, which calculated the ocean surface waves’ max height to be 15 meters?
Well the planes won’t need to land anyhow, so we will just beam the passengers aboard.
And flying will be much safer. There won’t be any birds in the air due to the density altitude problem.
So all the birds will get eaten by feral cats, unless they evolve back into the mean SOBs they were in the age of the dinosaurs.
Now this has to be the ultimate in butterfly effects discoveries.
Severe weather will become a thing of the past, because the flap of a butterfly’s wing in the Brazillian jungles (if any are left) will be quite imperceptible and incapable of triggering tornadoes.
Can I get some grant money to continue this Tom-foolery further ??
“We’ll all be rooned!” said Hanrahan, “We’ll All be rooned!”
RGB,
I normally find myself in violent agreement with your intelligent posts however in this instance I’m not.
Aircraft designers have sought to maximize lift and minimize drag since the earliest days and that fundamental equation has not changed, nor will it ever.
Aircraft are highly specialized because of the conflicts between those two objectives. An advanced airfoil with leading edge slats and drooped ailerons on a super-cub based design will get you on and off the ground in an amazingly short distance, but you won’t go very fast. Alternatively a slick composite speed demon equipped with the same horsepower will take forever to leave the ground but will travel at speeds that take your breath away.
Fundamentally the same principles and conflicts apply to commercial transport aircraft and the ingenuity of the engineers to minimize drag but maximize payload, read lift, are driven by factors much larger than a few days of potential weight limits at a few high altitude airports. To use an expression of my grandmother “This study is war’n than my a**.”
Ummmmm?.
Isn’t one of the busiest airports in the world in Dubai ?
Never gets warm there, I guess. !
You don’t understand. Because it will get searingly hot everywhere the planes won’t be able to take off from Edmonton or Dubai. You see Edmonton will have reached 50°C and Dubai 100°C.
See ? You just don’t understand :))
Dubai has better than 14,000 ft available for takeoff.
I gather the A380 needs less runway length than the 777 and both types fly in and out of DXB all year long, including their roastingly hot and humid summer.
If you need money any old sh&t will do. Bull or otherwise
Every once in a while, about twice a week, one of these really, really childishly stupid papers turns up. Who OKs them and who pays …………………………………. Oh I know, we pay and they order them to top up their bank balances.
I haven’t read all the postings, but won’t the warmer air be positive thing? The planes will be able to fly faster at a given altitude because the air is less dense? Or am I wrong?
Cant accuse Climate Alarmists of Reductio Absurdium because they,ve already done it to themselves
No problem, paint the runways white.
its a good thing there is no global warming going on …
During the ‘80’s I lived and worked in Libya. The international airport outside Tripoli is located adjacent the town of Azziziya, one of the former (recorded) hottest places on earth.
Western European and US manufactured planes took off and landed at all hours and all seasons. Russian manufactured (tail heavy) Ilyushin and Tupolev aircraft “du jour” could land at any time and any season, but their departures in the summer season were limited to the wee hours of morning. I recall that on several occasions, the nights didn’t cool sufficiently and the flights were suspended until conditions improved.
Private aircraft (mostly DeHavilland Twin Otters) flown by expatriate Canadians had no difficulty flying in worse conditions in the hotter desert regions of Libya. On several occasions I witnessed Twin Otter takeoffs from the short taxi strip connecting the hanger to the airstrip at these remote sites. (see above joke from Les Johnson.)
If the paper-report had come from the aerospace industry then I would be concerned. As it is the folks at Columbia Univ Climate Department should limit themselves paper airplanes.
Oddly in the aerospace industry “models” for design purposes are of some utility. But of course the Engineers tend to know how things work and why things work, at least in my past experiences
michael.
Sometimes the biggest challenge is to get it back on the ground ( there are tons of these videos out there).
The ones touching down while in a crab are scary. I notice some of them straightened out before touchdown but the others have to be applying some really nasty side forces to the gear.
The only landing I ever “greased” was on a night training flight to get my private pilots license.
What does that tell ya, throw out the visual cues and fly by the seat of your pants ?
Or are you just smoother on the controls when groping around in the dark ?
Anyone who has flown in to and out of Wellington, New Zealand knows this all too well.
Someone should tell the authors about La Paz, Bolivia.where the airport is at 13,000 ft. All they need to take off and land here is a special set of tires (225 mph rated) and the more powerful engines. Don’t forget that the Concorde take-off speed was well over 200 mph.
15,000 feet, I was told by my Bolivian friend. LA Paz is at 14,000 and the airport is located on the alti-plano, 1,000 feet above the city.
Correction: LA Paz seems to have shrunk. It is now only 12,000 ft high and the airport is at 13,000, as given by Dealt D above.
I hadn’t realized all the airports in the world have the exact same temperatures. I guess the thinking is that even though different regions have different average and peak temperatures, apparently the airports all have the same temperatures since today different air densities in different regions are not a significant issue. Only when you put climate change in the sentence are variations in warmth important areas of concern.
so why not fly at night when it is cooler?
As far as that goes, aren’t we all going to be living in northern Canada and Siberia by then? You know, climate refugees?
Once there’s no more ice covering Antarctica, we could build a big humming airport there.
Glancing at the periodic table, won’t all that extra CO2 INCREASE the air density? /SARC
There are 5 major airports at heights above 4000 m.
http://en.wikipedia.org/wiki/List_of_highest_commercial_airports
At this altitude, air pressure and hence lift, is less than 60% of that at sea level.
“Global warming” has produced a warming of 0.8 degrees in the past 111 years since the first powered flight. This would result in a reduction in lift of 0.3%. This is ridiculously trivial compared to the 40% reduction in lift at some airports.
To bolster sagging support for the Democrats, Pres BO will shortly announce a program to land a Presidential hopefull on the sun and return her, “by the end of this decade”. When questioned about technical details likely to plague the mission, sources close to the Pres replied “we will send her at night.”
Oh, my these people are creative at finding more things to be alarmist about.
They narrowly focus on one subject, evading benefits of warming (including fewer icy runways?).
What was the payload of airline flights out of DEN and MEX in 1936?
There are models for everything. Unfortunatly there aren’t good it-educated systemprogrammers among the AWG belivers….
Where have all the money gone?
How do they takeoff at Las Vegas on a hot day even now when the temps are 100+F? Are we to assume the temperature will be in the 90’s and 100’s everywhere and every day in the future and all from a 0.1C rise in the global mean?
Some Boeing 737-800 data for you. Ok, so let’s choose some different runway lengths.
2,400m, which is quite short for a 737-800.
Max t/o weight: … 30º = 76.6t … 38º = 73.0t.
Or about 450 kg per degree centigrade.
2,800, with is nice for a 737-800.
Max t/o weight: … 30º = 82.5t … 38º = 78.5t.
Or about 500 kg per degree centigrade.
Max t/o weight of the 737-800 is 79t. So if the temperature increases by 2 degrees, you will lose a tonne of weight – but only if the runway is very short. If the flight is less than 6 hours, you would never take off with max weight anyway. 75t is more than enough, for a 4 hour flight.
So how many airports will this temperature increase effect? How many US airports have runways less than 2,800m long? Not many, I imagine.
.
But what this report fails to mention, is that two degrees of temperature increase could easily be overcome, if Boeing got off its fat rear-end and designed a new aircraft. The original 737, had four engines…..
They called it the 707:
http://www.air-and-space.com/20060302%20LAX/DSC_3524%20707-330B%20N88ZL%20front%20l.jpg
Which then became the 727:
http://cdn-www.airliners.net/aviation-photos/middle/4/1/1/1811114.jpg
And then became the 737:
http://skybotechnik.com/wp-content/uploads/2011/10/Boeing-737-800-e1319143021830.jpg
And is about to become the 737 Max:
http://cargofacts.com/wp-content/uploads/2011/08/622-Boeing737B.jpg
Yes, Boeing is going to be making an aircraft that is going to be in service for 100 years. Bravo for Boeing, that is 35 years longer than the interval between the first flight of the Wright Flyer and Concorde.
And the trouble is that this is the 707 cockpit:
http://www.geocities.ws/CapeCanaveral/Hall/6690/2-BEIRUT1N720JRB720cockpit-062.jpg
And this is the latest 737-800:
http://www.creativesimulations.com/737%20Cockpit.jpg
Hmmm, not a lot of change then. Ok, so there is a new wing and new engines, but this is still a 1958 design, still in production.
Just imagine if you went to the Chevy dealership to buy a car, and they had this in the showroom (1958 Impala):
http://4.bp.blogspot.com/_QlMkZ-ZvBAY/TJCK5gXjRTI/AAAAAAAAAdc/PWx7F-oBaoc/s1600/58impala.jpg
Or to the Ford dealership and they showed you this. (1958 Ford Custom 300):
Clearly, there is a great deal of room for improvement, in the small aircraft market. Improvements that will overcome a two degree temperature increase in a trice. And you can bet that if Boeing does not do this, and make an all-new design, then China will.
Ralph
Your aircraft pictures are missing the central processor.
That one between the pilots ears 🙂
China only counterfeits and reverse engineers stuff.
Hmm…. yes please to the cars. But the reality is that whilst the body shapes and interiors have changed, the engines have not necessarily kept up. Most engine blocks and heads are re-used examples from the fifties and sixties. They perform better due to engine management systems (due injection and so on).
Sorry, but that is completely wrong. In a few isolated examples, companies may be using old engine designs (Bentley perhaps?). The vast majority of new design car engines have precious little to do with their predecessors, easily eclipsing them in power, weight, size and efficiency. Even the ‘old’ Chev Smallblock has only the basic measurements the same – everything else is in different materials, to a different design, with drastically different results.
Actually, Bentley is now owned by Volkwagen, and uses a state-of-the-art VW engines. The normal engine of choice is the remarkable W12, which was made by fusing two V6 engines together.
http://www.indiancarsbikes.in/wp-content/uploads/2012/02/A-cutaway-of-the-W12-Petrol-Engine-on-an-Audi-A8-Copy.jpg
You have to understand that alarmists are not aware that species can adapt, especially humans, engineers, farmers, even over centuries.
I don’t know why you are all being so dismissive. When that fluffy white Global Warming piles up a metre deep on the runway, the planes simply can’t take off. And, as a result of Man Made Climate Change, that sort of thing is happening more and more frequently in the Northern Hemisphere.
But if they are worried about the warm type of Global Warming, perhaps they could find out how the airlines and the Flying Doctor manage in Central Australia.
What’s new?! My son regularly flies large aircraft out of Dubai all summer. That is HOT. He flies into all sorts of places with very different weather/climates. Good grief! The piece is full of the usual could/might scare stuff.
Heck, don’t give them too much grief about this… maybe some poor Grad Student managed to get his MS out of this!
I think that the authors of the paper are forgetting that aeroplanes and airports airports are not slaves of their genes and chromosomes as we and the whole natural living world are.
Therefore, if it does become a nuisance taking off and keeping to schedules etc. (assuming that significant warming is the cause,) – well – how long would it take aero industry to fit bigger flaps – more powerful engines – bigger wings etc to solve the problem?
It won’t be millions of years I assure you.
Once again the taxpayer has footed the bill for this nonsense.
Cheers
Roger
http://www.rogerfromnewzealand.wordpress.com
No worry. The IPCC referenced climate change models are primitive and erroneous. They fail to characterize water vapor (the largest greenhouse gas), clouds, solar effects, and aerosols, among others. For example the average of 44 recent models showed 2012 warming more than three times the values actually recorded by satellites that measure global temperature with an accuracy of plus-or-minus 0.01%. Additionally, the models did not predict the lack of warming in the last 18 years.
I love it. A reference citation in the first sentence of the abstract. One premise, with one reference, upon which the whole house of cards is stacked. Usually a no-no to cite in the abstract, in my memory.
It’s a good thing modern planes will be obsolete by 2050, replaced by aircraft with more efficient lifting surfaces, reduced drag, lighter weight, and more powerful, more efficient engines.
So planes will fly less and less carbon will be emitted into the air. Once again another negative feedback that has been ignored in the drive to make global warming as bad as possible.
The only reason that this becomes a crisis is because all of the government and ngo fat cats couldn’t then fly to some exotic location and sit in air-conditioning whilst whining about what other people are not doing about global warming.
I remain an optimist – I truly believe that one day the world’s leaders will wake up and realise that having these meeting where they crap-on about climate change, changes absolutely nothing (please excuse the Australianism).
In the meantime I suggest that only those people who can get there by bicycle, donkey, canoe or on foot should be allowed to attend and when they get there they should be allowed only to eat the equivalent of an average meal and sleep in crowded rooms, just like the vast majority of people in the world do. Until then they are just a bunch of utter hypocrites who have no right to say anything.
So I’m just not going to fly in and out of Denver in July. What’s the big problem?
Denver Airport (DEN) is a great example. That 0.7 degree C increase in global temperature (which has since abated) just about put them out of business. You may have noticed your airline tickets to The Mile High City included the disclaimer, “Invalid if Denver has a particularly hot day”. Whatta’ load! Thinner air means longer runways and that’s all it means. A plane that can fly at 40,000 feet can most certainly take off from any runway in the world regardless of ground temperature, if the runway is of sufficient length.
Move the thermometers away from the tarmac and jet engines.
That should lower the temp by 5degrees.
Then takeoff normally.
This is complete drivel. By 2050 we’ll have fission energy and anti-gravity. Then, we don’t need no stinkin airplane.
I wonder what is new or news in this. The aircraft flows through different temperature and wind regimes with space and time. Also aircraft differ in terms of temperature vs load. Accordingly the load to takeoff. At given place the temperature and wind regimes vary with seasons and cloud condition, etc.
Dr. S. Jeevananda Reddy
Couple of writers above have mentioned development and invention and new technology.
Lettuce “model” that progress between “now” and “the CAGW crisis” point 40 years from now in 2054 – only 40 years in the future!
So. Build me an airport in 1908.
(Hint: Only a very few planes in the world could carry passengers (first passenger went up with the Wright brothers) and that only for a few minutes of flight.) Steering was hard to do.
You would need:
A pasture. (And a fence to keep the cows out when you wanted to land.)
A tent for the mechanics. Their toolbox.
A can of gasoline.
Now. Build me an airport 40 years later. 1948. In Maine.
You would start with two 10,000 foot runways.
300 feet wide, of reinforced concrete 3 feet thick in the landing area.
Built of concrete for B-36 bombers, taking off with almost 800,000 pounds of aircraft and fuel for flights of over 24 hours duration.
You need hundreds of thousands of sq feet of concrete-paved taxiways, access ways, maintenance areas and parking pads.
10,000,000 gallons of fuel in a separate and secure tank farm.
500 more acres more for the weapons facility and its facilities.
Room and buildings and services for 4,500 military crew, maintenance and support personnel – plus all of their dependents and their services.
Hangers and tool cribs and machinist and services and part warehouses.
Yeah. No progress in aviation is possible in 40 years.
But, you see, the CAGW religion WILL require we kill millions worldwide very year using THIS PAPER as one of their excuses to cut carbon emissions to “prevent catastrophic global warming!”
When what is needed is a weight and power calculation ALREADY BEING DONE NOW for the few airplanes taking off in four airports worldwide for a few weeks each summer.
Maybe.
“… and that airplanes of the 2050-2070 era have the same airfoil efficiency and takeoff power of today. …”
One wonders how airlines cope operating from Saudi and Gulf State city runways in Summer then? Look at a heat map of that region in mid summer and it’s noticeably hotter than most other places on Earth, on any average summers day, and yet they still seem to manage to operate fully loaded A380s, 24/7, no problems at all.
If density-altitude is a limiting factor for a flight the classic answer is to use a longer takeoff roll to rotate at a higher speed (i.e. you could just extend the runway a few hundred meters – solved), or else remove some payload weight (less passengers, less cargo or less fuel) then fly within the certification ISA>+20 limits in the AFM.
Some aircraft are actually limited by temperature, already, due to the black rubber anti-iceing boots on the leading edges of wings and empennage. Yes, the anti-ice boots are used just as much on hot days as well if there’s visible moisture on the climb-out. The air above is still very cold and ice will readily form in moist air (and hot air is on average always much wetter than cold air). The black rubber boots get so hot that if bleed air inflates them on the climb-out the rubber boots can be permanently deformed or else split, and require (expensive) immediate replacement. Which is why the boots are not used on new jets but many new turboprops still use them.
I seriously doubt density-altitude due to high temperature at sea level will ever be a flight limitation though, it has to be combined with actual altitude, such as ISA+30 conditions at a 6,000 foot elevation airport with a 3,000 foot runway. But even then the usual solution is to extend the runway and lift off at a higher speed. There is no insurmountable issue here, even if you were using 1950s wings and propulsion technology.
Examine graphs in any POH/AFM for a turbine aircraft and you can plainly see that density-altitude calculation is only a consideration for determining the appropriate takeoff distance and certified allowable weight.
There are downloadable phone or ipad apps for that calculation for most aircraft these days, it’s hardly a big deal. And it’s not a factor which determines a ‘go or no-go’ decision. It’s just something more that’s taken into account is all.
Verdict: density-altitude-induced-aviation-doom is yet another hyperbolic scare-campaign from climate-doomer dumb-dumbs.
These climate-doom schmartasses really should wait until they grow out of their nappy-wearing stage before they presume to enlighten people who’re several decades older and vastly more experienced with weather and climate, and how the world and technology really works. The young are supposed to learn from their older, not due to some sense of pontificating seniority, but simply because the older do actually know things which know-it-all students and 20-something post-docs still doesn’t know anything about – yet. And despite this clear indisputable total absence of real world life, work and community and political experience, the young fool then resolves to try to ‘educate’ these ignorant old fools, and tell them all about their pending doom. It’s the perpetual common-place error that happens every generation as students discover a few new and novel pet ‘issues’, and proceeds to self-appoint themselves as expert authorities and avidly adopts the Henny-Penny “the-sky-is-falling” tragi-comedy archetype, and sets about to militate and tirelessly warn the older about the great evils of their habits and complacency, and the sum of all diabolical foolishness, which they are here to put right.
Doncha love how they do that.
@ Ralph
“Clearly, there is a great deal of room for improvement, in the small aircraft market. Improvements that will overcome a two degree temperature increase in a trice. And you can bet that if Boeing does not do this, and make an all-new design, then China will.” – Ralph
—
If you know all that which is within your post, then you should also know that airline boardrooms are constantly looking for lower drag lower fuel burn and operating costs per nautical mile, and are constantly changing aircraft as these improve, simply because the cost of fuel burned by an airliner dwarfs the cost of buying a new jet. This it is much more economic to constantly buy more efficient jets and to retire to the boneyard a jet that may be as little as ten years old – or less.
This happens all the time. Which is another way of saying, there is a powerful economic incentive for jet manufacturers to constantly improve and optimize and innovate their jet designs. There are massive differences in efficiency and cost per nautical mile between a 1950s 707 and a 2014 737.
You are assuming that the basic design need radical review and a total revolution in ideas, and presume that this has not in fact occurred. But it has, and that is why you have the current 737s and Airbuses. If it were possible to make a significant major difference to airliner efficiency (as opposed to incremental improvements we see), it would have already occurred.
The history of aviation is littered with the many attempts to design a better turboprop or jet airliner. Indeed people dis them, but turbo props are almost as fast and much more efficient than jets, but airlines simply won’t buy them. The Russian ‘Bear’ maritime patrol turbo-PROP aircraft has a max cruise speed of 510 knots(!!) with contra-rotating props. For contrast a Boeing 747’s maximum cruise speed is about 20 knots SLOWER that this ancient Russian turboprop! So now you know why the Russians keep them in service, it’s because these old propeller-driven jalopies can out-pace and out drag a modern fighter flight vectoring to intercept them!
Yeah, so like, everyone knows that turboprops are just slow and really crappy, right?
Tupolev Tu-95 ‘Bear’
Maximum speed: 920 km/h (510 knots, 575 mph)
Service ceiling: 13,716 m (45,000 ft)
Range: 15,000 km (8,100 nmi, 9,400 mi) unrefueled
Empty weight: 90,000 kg (198,000 lb)
Max. takeoff weight: 188,000 kg (414,500 lb)
If that doesn’t make you double take on your ideas of efficiency and technical advancement and that maybe jets per-sec are not the economic and practical efficiency solution then maybe this will, it’s the European’s answer to the US C-17A, the A400M.
https://en.wikipedia.org/wiki/Airbus_A400M_Atlas
Airbus A400M
Empty weight: 76,500 kg (168,654 lb) ; operating weight[98]
Max takeoff weight: 141,000 kg (310,852 lb)
Cruising speed: 780 km/h (485 mph; 421 kn) (Mach 0.68–0.72)
Initial cruise altitude: at MTOW: 9,000 m (29,000 ft)
Range: 3,298 km (2,049 mi; 1,781 nmi) at max payload (long range cruise speed; reserves as per MIL-C-5011A)
Range at 30-tonne payload: 4,540 km (2,450 nmi)
Range at 20-tonne payload: 6,390 km (3,450 nmi)
Ferry range: 8,710 km (5,412 mi; 4,703 nmi)
Service ceiling: 11,300 m (37,073 ft)
And then there’s this current example of innovation, a small 400 kt turboprop with a 41,000 ft ceiling:
http://en.wikipedia.org/wiki/Piaggio_P.180_Avanti
So very old and very new turboprop aircraft have directly comparable the speeds of jets. They also have similar high ceilings and reliability levels and the exact same safety systems, plus routinely provide efficient narrow and/or wide-body haulage of enormous payloads, to long range destinations in ‘hot ‘n high’ density-altitude conditions.
So the basic air transport problem is not the design potential, nor the hardware and propulsion and materials options that can be mobilized to build with far greater efficiency, to do the same job, just as well. The real problem is that the flying public simply distrust propeller-driven aircraft and perceive them to be less safe, even though we actually know they’re every bit as safe as a jet, far safer in fact is some phases of flight, such as the approach to land.
As a result, airline fleet buyers do not create a demand for and do not request to buy the vastly more efficient high performance turboprops as a viable and worthwhile solution. Props are simply considered passe!
Plus airline manufacturers and operators have to meet stringent regulatory safety requirements that many alternative novel designs simply can’t efficiently attain when it comes time to perform the super expensive certification trials. If they fail they have to go back into development, then re-test again, which is extremely expensive. So conservativeness of design and using what is known to definitely work and meet the required standard, and also what the flying public will agree to sit in and fly on, is what matters the most to manufacturers and airline operators.
Radical efficiency through change is not a good thing for either. The public simply do not trust radical changes in airliner design. For instance, a recent over-reaction to new innovation within a fairly conventional twin jet aircraft design, an example in August 2014 from the NY Post:
http://nypost.com/2014/08/08/terror-filled-flight-as-planes-engine-fails-over-atlantic/
So if we’re going to go into efficiency of aviation designs, and slow pace of innovation, there’s a whole lot more to it than just comparing photos of then and now, and suggesting that not much has changed.
(btw, your photo of that 1950s 707 cockpit has a late 1990s era GPS RNAV moving-map display system sitting atop its glare shield … things like satellite constellations allowing precise global area-navigation have in fact changed quite a lot)
Tupelov Bear doing 510 kt at 45,000 ft. Oh, yes, and pigs may fly. You don’t believe the Russians, do you? Dear me, I presume you also believe that MH -17 was brought down by a ground-attack aircraft that cannot fly at more than 25,000 ft.
So let’s look at that claim. Doing 510 kts at 45,000 ft is mach .89. Do you know how fast that is? The B747 is the fastest major commercial aircraft, and it only does .83. Do you realise that a turboprop at .89 would have supersonic prop blades? Do you understand the problems?
If the Tu-95 does have a high speed, it will be at low level, say 20,000 ft, where mach is not so muchof a problem. Remember that mach is proportional to temperature, so the lower you go the faster you go.
Why did Boeing and Airbus not use turboprops? Pass on that, it may simply be fashion. It is well-known that a small jet would be much more efficient as a turboprop – but usually turboprops are limited to about 350 kt, otherwise they become inefficient. That is 100 kt slower than a 737 at altitude.
Try getting a link to the max mach number for the Tu-95, if you really think it will go that fast.
Ralph
Silver ralph
Mach numbers are specifically and ONLY related to the speed of sound in the density of air at the altitude and temperature of the air at point where the aircraft was traveling.
Air density changes dramatically with altitude, speed of sound changes dramatically with altitude, temperature changes dramatically with altitude. However, the speed of the aircraft OVER GROUND DOES NOT CHANGE with altitude. The double-prop, contra-rotating Tu prop’s are a remarkable invention that have been successful and far more efficient that the early jets, the early turbo-props, and most engines built since then. The original Tu-85 straight wing and its fundamental air frame and ultra-smooth riveted assembly were copied from (liberally speaking) the US B-29 aircraft captured in Russia in WWII, the later Tu-95 added the turbo-prop engines and swept wing to increased performance. Engine, supercharger, piston-ring/engine pressure and propeller design has continued since the 50’s – records attempted with high-camber/high-speed propellers and low flight weights are NOT going to reflect “normal best-economy/best-altitude/best-performance” propellers.
ground speed records are claimed based on wind speed and wind direction as well: The upper air wind speeds (northern hemisphere from west to east) make ground speed records easier (faster) when travel from west-to-east. The 510 knots ground speed is easily possible even without substantial jet stream assistance.
Look again at the details of your charges about Mach number, and only use ground speeds to compare performance. NEVER Mach numbers.
>>NEVER Mach numbers.
Utter rubbish. You are obviously a wannabe, who has never flown a jet in his life.
No aircraft flies on TAS above 28,000 ft. It is mach and mach alone, that determines high level airspeeds of aircraft – which nullifies your compariton with a 747 and modern jets. And the fact that the TU-95 is quoting TAS clearly implies that this 500kt claim is a speed determined at low level.
And using wind to determine groundspeed? Eh? What an infantile claim. I have has a 190 kt tail wind, before now, does that mean I have been supersonic while only doing .70 ?? Absurd nonsense.
Ralph
I mean ‘to determine a groundspeed as the performance speed of an aircraft’.
Clearly, the perfomance of an aircraft is determined by the relative airflow over the aircraft, as measuerd in TAS or Mach. Adding windspeed to form a bogus ‘performance groundspeed’ is a suggestion worthy of a kindergarten.
R
@ Silver ralph:
“Tupelov Bear doing 510 kt at 45,000 ft. Oh, yes, and pigs may fly. You don’t believe the Russians, do you?”
—
Nowhere did I say that a Bear does 510 kt at 45,000 ft, that was an assumption that you made. What I said was this:
“… The Russian ‘Bear’ maritime patrol turbo-PROP aircraft has a max cruise speed of 510 knots(!!) with contra-rotating props. …”
And then I referenced its purported basic specs, one of which was “Service ceiling: 13,716 m (45,000 ft)”.
Get it now?
I did not have to “believe the Russians” when I provided that, I simply referenced a Wiki page which you’re free to edit and backup with evidence, if you feel so confident to correct it, given you know the truth of such things.
By the way a propeller is not a helicopter blade, the prop is not leading into the airstream and accelerating against the airstream, it is simply rotating perpendicular to it. i.e. the tip speed is a function of RPMs and prop blade length. Do you also know the RPM of the props too then? Your comment about transonic issues (namely shock cavitation detachment of the airflow) was inapplicable blah-blah.
If you have actual evidence that a Bear can not achieve 510 kts (and remember, this speed can be measured whilst empty with an aircrew and low fuel flight, the weight and altitude were not given) then do so, otherwise your objection is blah-blah.
However, I do agree with you that ground speed has nothing to do with that speed claim, it is indeed a Mach measurement of airflow via pressure measurement with respect to the airframe’s passage in it.
Btw, 747s were certified for to max cruise at ~492 knots which at FL330 (the typical max speed altitude for most jets) is Mach 0.845, not Mach 0.83. Yes, I’m fully aware that a jet or turboprop does not achieve its max cruise speed at its certified altitude ceiling. That speed usually occurs at about 2/3 to 3/4 of its altitude ceiling.
But the actual general point made by me, which I note that you completely ignored, was not about nit-picking over specs, it was to show that turboprops are neither definitively slower than jets, nor as expensive to operate and that they’re equally capable of flying enormous payloads for very long distances comparatively cheaply and fuel-efficiently, and likewise that they too can operate and remain stable above almost all tropospheric WX, in the same way that jets do, and to achieve similar range boosting effects at such altitudes.
Jets don’t have almost any clear advantage.
And I provided two other examples of precisely that, the A400M, and the Avanti-II, which you also ignored. So what did your remarks clarify or alter, what point did you make that changes what I’ve pointed out?
Next time write an actual counter-point if you want to be taken seriously when calling into question airliner design and efficiency and the options available. It isn’t a pi**ing contest, it’s just a discussion.
By the way a propeller is not a helicopter blade, the prop is not leading into the airstream and accelerating against the airstream, it is simply rotating perpendicular to it.
________________________________________
Again not true, which again shows you are a wannabe, who has never flown a large cargo turbu-prop.
At zero speed the blades are fine. As speed increaces the blades coarsen into the airflow, to maintain the required angle of attack/incidence. So at high airspeed, the blades receive a rotational airflow vector determined by engine rpm, and also an airspeed airflow vector determined by aircraft airspeed. So for any given rpm, the blades will indeed experience a greater airflow speed, when the aircraft flies faster, and therefore may go supersonic as speed increases.
The Wiki page says the prop-blades do indeed go supersonic. But I would doubt that, as designers stay away from supersonic blades, as they are inefficient. I imagine the blades CAN go supersonic, in certain flight regimes, but normally operate subsonic.
And if the Tu-95 is achieving its high speed at low level (and I still doubt such a high TAS figure), your comparison with a 747 is nonsense – the 747 will also do 510 knots at low level. But most pilots and passengers appreciate being up above the weather – so why sit down in the CBs and icing, when you can be up above it all? And jets are more efficient at high level.
It may be true that Boeing could make a more efficient low-level turboprop-powered 747. But efficiency is not the only consideration, when designing an aircraft. And a wannnabe would not begin to understand what those considerations are.
Ralph
Prop driven aircraft can and did exceed the speed of sound in WWII though none survived to tell the tale…getting a prop tip through the sound barrier is no different from getting a wing through the sound barrier, and that is that.
The real point is it actually the most efficient way to do stuff? Generally its not worth going supersonic for passenger and freight as the cost jumps dramatically. Commercial aircraft are flown on the plateau representing the most return on investment in fuel and airframe per year. In reality that represents most planes not in a headwind or late, cruising at not much over 400mph. Which a turboprop can easily reach.
It is rare to exceed 500mph, though both jets and props can.
Arguably a modern turbofan is halfway to a turboprop anyway. The actual physics show that for a given cruising speed the optimal power unit will have a large mass of air accelerated to just beyond the cruising speed to provide the thrust. That means large diameter intakes and exhausts (or propellors) and subsonic exhausts too. Small high velocity exhausts – pure jets – do not make for efficient use of fuel, until the airframe speed starts to match the exhaust velocity.
The A400M shows a design which has (probably) been compromised on fuel efficiency, but not by much, as it has a pretty good range – to optimise STOL capability especially on rough landing fields.
In short, all options are open, and there are no absolute limits on what type or layout of aircraft would be needed to compensate for hotter thinner air, the problem is essentially trivial to non-existent, and the fuss made about it out of all proportion to the problem.
Even if there is a problem, which one doubts.
“””””…..
Leo Smith
November 29, 2014 at 4:01 am
Prop driven aircraft can and did exceed the speed of sound in WWII though none survived to tell the tale…getting a prop tip through the sound barrier is no different from getting a wing through the sound barrier, and that is that….”””
Can you provide a reference to ANY documented case of ANY WW-II aircraft (1939-1945) ever exceeding Mach 1.0 even in a vertical full power on dive.
I’m not aware of any.
I am aware of a very deliberate case of a power dive from high altitude, circa 45,000 feet, by a pilot trying to escape from a cracked canopy risk of depressurization. With a two stage supercharged RR-Griffon engine (needed to reach that altitude), he never got close to Mach one at any altitude and speed.
The dive was monitored by radar, as well as the pilot’s reports. He did get into that whole control reversal mode, but never went Mach one. The flight was studied by the chief test pilot for that aircraft, who stated that it was impossible to reach Mach 1 in that aircraft. And it was not even the fastest prop plane of WW-II by a long shot. It was an aerial reconnaissance type designed for high altitude. (Mark XIX Spitfire I think; maybe a Mark XXI)
If I’m not mistaken, that recon flight was the very last official RAF mission by ANY Spitfire, and took place somewhere in Asia; probably Malaysia. Post WW-II of course.
Faster types, like the Hawker Tempest, also never went supersonic. Even ME 262s couldn’t.
Chuck Yeager really WAS the first. The rest is fairy tales.
As a rule I NEVER rely on specifications produced by a manufacturer’s *marketing* department.
Nor do I, I check the AFM because it is a regulated certification document specified for use within the formal certification approval, and it’s legally required to be accurate presented measured data. However, that accurate manual does in fact come from the manufacturer, just not from the marketing/promotions/sales dept.
>>Unmentionable November 26, 2014 at 10:46 pm
>>I seriously doubt density-altitude due to high temperature at sea level will
>>ever be a flight limitation though, it has to be combined with actual altitude.
Oh, it can be. And extending the runway is not always the answer. Any airport with high ground or mountains around it, is going to have performance restrictions, no matter how long the runway is.
And then we have the WAT or Climb limitation, which kicks in at higher temperatures (no matter how long the runway is). The B737-800 starts getting WAT limited at 38º at sea level, and loses 5t of performance weight by 46º. At an airfield at 2,000′ altitude, the same weight limits occur at eight degrees cooler (30º and 38º). Extending the runway in these cases has little effect on overall performance.
But, as I said before, more advanced aircraft designs could easily overcome the proposed 2º increase in temperature, that the alarmists are forecasting.
And since there has been no Global Warming in 18 years – just what is the problem? Perhaps Coffel and Horton (the authors), should also investigate the dire problems aviation will face in the future, when aircraft start colliding with the offspring of Pegasus. Should TCAS be made compulsory for all winged equi? Now that is the real question…… 😉
R
“And since there has been no Global Warming in 18 years – just what is the problem?”
The problem is a former President’s daughters will (allegedly) have to forgo a jet flight to the Coral Sea because the coral will be gone for some completely unexplained reason, if the on-going total lack of change in global temperature continues to do nothing. I won’t go into here the fact that we natives were the ones who put it up for world heritage listing and debated and discusses and planned to create research and regulatory agencies to manage the coral reef, or that the workers on all construction sites, in all mines, in all trucks, trains, restaurant kitchens, cleaning toilets, teaching in class rooms and flying the public around from in cockpits are the very same people who elected to do all that to preserve the reef – AND STILL ARE BTW – and to likewise continuously pay a hefty price in on-going taxation to make sure that it was always preserved for all future generations of human beings to visit. Just a little thing there that Obama glossed-over and totally ignored, almost nothing at all really, as he grossly insulted us all with his baseless insinuation that the country was full of remorseless environmental vandals, and that the total lack of a temp increase for 18 years spells certain doom. But hey, who cares about reality when you have a snazzy teleprompter injected fantasy?
Re runway lengths and density altitudes, in all aircraft I’m directly familiar with the answer is to use a longer takeoff roll to rotate at higher speed and remove unnecessary payload weight (fewer people, less baggage, less fuel, perhaps necessitating a further fuel stop before destination) then fly within the certification limits and in all cases you’re going to get safely to cruising levels. Stay clear leeward ridge lines, best climb, turn early, std rate.
Yeah maybe some locations can’t build a longer runway, so takeoffs can’t be made faster, but there are always going to be those limits, and as you would know, there always has been. I don’t see any significant change/impact/disruption even if the models were right. In that case the economics, regs and operator practicalities would simply require a different aircraft type be used.
We also should not ignore that turbine aircraft are getting bigger and heavier with more thrust and payload with every iteration, in order to access the economies of scale efficiency dividends and that their numbers are increasing as well every year.
That is the real practical cap on airspace usage and capacity constraints (as I expect you understand), temperature is as I said, just one fairly minor factor within a much more complicated calculation, where other constraints are rather more significant than density altitude. Like you said, no temp change in 18 years – why are we forced to talk/debate nothing? (i.e. same problem/distraction at the G20 too … gee, how’d that happen?)
Now there’s a good question.
(Anthony/Mods, think I exceeded the link limit with a comment still in moderation )
meanwhile the Airlines keep figuring out ways to pack us in like lemmings in shinny metal boxes, more weight .. I guess they didn’t get the memo?
I was just wondering the other day if “Global Warming” would have a discernable impact on air pressures. More atmospheric heat, more atmospheric energy, more atmospheric pressure?
Instead of Global Warming, should we be calling it Global Pressurizing?
They say that the high temps on Venus are due to high pressures. High pressure fronts are often associated with higher temperatures than lower pressure fronts, at least from my layman’s view. Just curious, has there been any attempt to systematically look at whether atmospheric pressures have changed over time?
Atmospheric pressure (F/a) is a function of the total *mass* (m) of the air over a given unit of area (a), under the influence of gravity (g) according to the equation F=m*g. None of these factors will be significantly influenced by temperature. A gram of hot air weighs exactly the same as a gram of cooler air.
The issue for aircraft performance is air *density*, which varies with temperature AND humidity.
Read these:
http://www.pilotfriend.com/training/flight_training/met/atmos.htm
http://www.pilotfriend.com/training/flight_training/met/atmos_wt.htm
This is one of the posts that Sou (Miriam O’Brien) has chosen to comment on at HotWhopper. See my post at MoreOnMiriamO’Brien’sHotWhopper:
http://moreonmiriamobrien.wordpress.com/2014/11/27/miriam-obrien-says-various-views-flying-about-at-wuwt/
In this post, Miriam comments on about a dozen comments. Wow! (sarc off.)
More weight is overcome by higher thrust. Higher thrust of newer engines comes from burning about the same quantity of fuel at a higher temperature and pressure, in the core of a larger diameter turbofan engine, with a much bigger fan. The aim is to achieve a higher core exhaust pressure therefore a larger and/or faster spinning fan, so higher thrust for the same fuel. So they make larger jets with larger payloads to get a better margin return on investment, so can stay in (a profitable) business. That, and better airfoil shapes and avionics precision, is airline efficiency growth in a nutshell.
What you’re referring to are to be blunt, “the cheap seats”, (in Titanic terms, “Steerage Class”) and those seats only exist at low price due to those efficiency gains. So the cheap seats only exist due to that efficiency growth, and most people who fly can only fly because that efficiency made affordable airline seats possible, for a larger proportion of highly mobile people in the economy.
Sorry, not much dystopic consolation to offer but there it is, the filthy proletariate can enjoy flying with the Promenade Deck Class Jet-setters. Are you not ever so lucky when you think about it in those terms? And within the same jets you volunteer your mortal soul to fly there are also not-so-cheap seats, for the, er, more aspiration oriented, which look like this:
http://www.news.com.au/travel/travel-ideas/what-its-like-to-fly-on-the-20000-singapore-airlines-suite-class/story-fnjpj945-1227076691741
So keep working really, really, I mean reeealy hard and one day you may be privileged to blow $20k on not very much at all. No doubt, now that you realize you’ve been arriving at the very same destinations, for years, at comparatively negligible cost, this has cheered you up enormously, as you realize what a lucky sod you have been all this time.
The greatest weakness of the alarmist view is their flawed fixation on the static nature of things. We live in a dynamic and vibrant world where the only constant is change itself. The fact that everything is in motion and consantly evolbing is utterly ignored by those screaming about catastrphe.
Back in my day we called misjudgements involving density altitude, overgross weight, underestimated takeoff roll etc. Pilot error…….. now it’s climate change? ah! well you live and learn.
Easy fix:
*Arrive & depart in mornings or evenings
*Bigger wing or bigger engine
*Less weight (alarmists banned from flying….)
*Give the aero engineers a few minutes, they’ll figure it out.
*Biggest problem we face is when it gets colder, not hotter.
Ron Richey
N70NB
Easier fix: Don’t fly. Use the Internet for conferences and telework. The less time I spend around TSA agents the better I like it.
PS: Happy Thanksgiving
Here’s a link to a B-29 Flight Manual if such things interest you. Takeoff performance starts at about page 100. http://www.avialogs.com/viewer/avialogs-documentviewer.php?id=2717
With reduced lift comes reduced drag so overall there will be a benefit for most of the world’s air transport.
Either they fly lower to get the same limit point so do not have to climb so far or they can fly higher and save fuel. That is not so good for climate alarmists to publicise, is it?
Reblogged this on Centinel2012 and commented:
In the view of the Greens fewer planes would be a good thing!
As we say, it´s hard to fly like an eagle when you´re surrounded by turkey´s
apostrophe catastrophe – try turkeys
See
http://www.greatseal.com/symbols/turkey.html
http://www.chron.com/life/article/The-turkey-was-almost-our-national-bird-1732163.php
The authors said their model predicted take-offs with weight restrictions “will increase by 50 to 200% at four major airports” in the US. Oh, really? That could mean increasing from 2 days to between 3 and 6 days. Or, perhaps it means increasing from 20 days to between 30 and 60 days. Since they specified a percentage and NOT actual numbers (at least as far as can be seen in the abstract), it seems they opted for sensationalism. I would have given them more credence if they had reported an avg number of days +/- s.d. and then stated the model result. Of course, I wouldn’t have to guess or infer if I could read the paper.
Why should we take any claims seriously unless we can see the data? I don’t care to leave the analysis to the “experts” who may very well have a conflict of interest in telling me the truth, whatever that is.
It is encouraging that ‘environmental scientists’ are learning about issues such as these. It is disconcerting that they were able to become ‘environmental scientists’ without knowing about them in the first place.
They have all exhibited the naive self-confidence of a sophomore since they starting raising alarms about the ‘climate’. They are now displaying the understanding of a third-year student. Still not ready for graduate-level work, though.
If a computer model said so, it must be true.
This relentless drum-beat of goofy and gauche announcements of global warming impending disasters is pulling down the whole genre of disaster prophecy to the level of self parody.
Once again its the end of the world as we know it and I feel fine.
A few decades ago, I had to delay takeoff from Phoenix Sky Harbor from late afternoon until almost midnight during a spell of 120° F daytime temperatures. [Boeing 737-300]
The problem was not airplane performance because of density altitude, although that is always in the calculation. Takeoff performance is calculated for every take off. “If it is off the chart it is off the menu.”
The reason for the delays, which was later “corrected” was that the performance data charts had not been established to that temperature. The “fix” was to establish performance figures for more extreme temps. The only change to make it “legal” was to correct the data base.
The same thing was a big factor in the Desert Storm and later mideast airlift operations. The idea that any believable global temperature change would seriously impact todays aircraft within their operational lifespan, or that future aircraft will not have better performance than yesterdays’ is worse than “unscientific” it is aeronautically “silly.”
We should, however, encourage overtly ignorant red herrings because the public, even the Gruberesque Stupid segment, can see through it.
The article that launched this thread sounds more like it was written by one of Al Gore’s Facebook “friends” than by a serious scientist.
Here’s what Robert Ballard (discoverer of the Titanic wreck) thinks about models. Go to 7.15:
Interesting video, thanks.
Great video, thank you for posting it.
Well the solution is quite trivial, and was seriously suggested back when SSTs were going to be the commercial planes of the future.
The answer was to simply build a continuous banked oval around the whole airport. Do as many laps as you need to get to take off speed in your desired (headwind) direction. No more crosswind landings either.
You first 🙂
I’d be glad to. I did some of my flight training at an old WW-II era air field that had eight intersecting runways in parallel pairs, forming an octagon pattern. My instructor would take me over there (actually verse vicea) whenever he wanted me to practice crosswind TO&L. Was quite a place with grass growing in every crack of the old concrete strips.
Anyway, on a banked track, going in circles is not a tracking problem. Nascar and Monza demonstrate banked circling.
Of course pilots know about air temperature affecting takeoff. But just how hot would the air have to be in order to prevent a regular commercial airliner from taking off? And would humans be able to survive it?
LonestrM makes a telling point: there are runways in the Middle East, where it gets hot all the time.
I remember a number of years ago when temperatures in Phoenix were consistently above 120F. At that time, the performance tables for most airplanes didn’t go above 120F. Now, most of that has been taken care of by computerized performance software. At high density altitudes now, maximum tire speed is the limiting factor.
A good topic for Burt Rutan, who has an incredibly detailed AGW site, and slipped below the radar years ago. His canard airfoils don’t have good STOL characteristics, and the Mojave Desert isn’t a cool spot.
http://rps3.com/Pages/Burt_Rutan_on_Climate_Change.htm
http://www.burtrutan.com/
I forgot this link with the video of Anthony Watts and Burt Rutan, the one I really wanted to post, 2012, and I’m glad I was wrong about Rutan’s recent AGW-sanity work.
http://www.burtrutan.com/
Who wants to come out and play ?