Questions tagged [temperature]

The intensity of heat found in an object or living thing.

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44
votes
6answers
20k views

What are some of the differences between piston engines used in aircraft and automobiles?

What are some of the differences between piston engines used in aircraft and automobiles? It seems aircraft engines are much more expensive, I imagine some of that cost must be due to the more ...
40
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2answers
12k views

Can commercial airliners fly over central Antarctica during winter?

For example, if an airline decided they wanted to run year round flights on the great circle from Perth to Buenos Aires with a commercial airliner (e.g. A380 or B747), would they be able to do so? Or ...
36
votes
3answers
71k views

How do aircraft keep fuel from freezing while in flight?

On aircraft which fly above 30,000 feet, the temperature can often can get to temperatures below Jet-A's freezing point. For example: at 36,000 feet the standard outside air temperature is -56.5°C (-...
28
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2answers
12k views

What is the typical temperature of an airliner's hull during flight?

Some high-speed military aircraft like the SR-71 had real heating problems, but airliners also travel almost at the speed of sound, use most of their fuel to make up for frictional losses, so I would ...
22
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7answers
5k views

What sort of issues related to extreme heat (115°F, 46°C plus) would prevent takeoffs or landings?

I recently flew into and out of McCarran Airport Las Vegas (LAS) and a local told me that they never report the air temperature at the airport above 115°F (46°C) because the FAA does not allow ...
20
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3answers
4k views

How do fast-flying aircraft avoid overheating?

As a follow-up question to What is the typical temperature of an airliner's hull during flight? I wonder how very fast airplanes, such as the SR-71 mentioned, avoid overheating with a total air ...
20
votes
1answer
6k views

How are temperature differences handled in a jet engine?

Given the graph in this answer, the temperature are quite high inside a jet-engine, even greater that many metal's melting point. I understand high core temperature are efficient. A jet engine is ...
18
votes
1answer
81k views

What is the difference between OAT, RAT, TAT, and SAT?

When I first started flying jet aircraft, I found different instruments that measure temperature in different ways and it was quite confusing. What is the difference between Outside Air Temperature,...
16
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2answers
4k views

What is the reason for setting flaps 1 on the ground at high temperatures?

Yesterday I've seen an A320 standing at the gate with flaps 1. While this question answers, why the flaps should be up, is there any reason to retract the flaps to 1 instead of up? In addition it ...
15
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1answer
3k views

Why can't Norwegian's Boeing 787 operate from Vegas during hot weather?

In a German news article it was stated that the additional weight (Norwegian puts 291 passengers on their 787-8) leads to operations restrictions in Las Vegas when temperature conditions exceed 40°C. ...
15
votes
1answer
4k views

Why do wings of passenger jet go dark during a flight?

Why do certain areas on passenger jet wings go dark during a flight? This effect is observed on high altitude where temperature is low. When airplane descends, wings return to their initial color. ...
12
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3answers
3k views

Does Nitrogen inside commercial airliner wheels prevent blowouts on touchdown?

I just watched the first episode of Inside Mighty Machine where civil engineer-turned-host, Chad Zdenek, discussed innovations of the 747. One innovation he discussed was the increased number of ...
12
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3answers
2k views

Is the altimeter setting corrected for temperature?

In an ATIS or AWOS/ASOS recording, is the reported altimeter setting corrected for temperature? I think it must be, because on a hot day, the altimeter should still show correct field elevation. If ...
11
votes
3answers
1k views

Do jet engine exhausts usually glow orange?

In these two lovely images: Source: Wikimedia Commons Source: wvi.com The exhaust end of the engines are glowing bright orange from being so hot. Do they get that hot during normal flight operations, ...
10
votes
3answers
4k views

How hot do internal parts of jet engine get?

How hot does a jet engine get? I'm interested in the temperature of the parts, not of the exhaust or combustion. If you took temperature of an engine after a flight across the Pacific Ocean what are ...
10
votes
3answers
77k views

How is pressure related to air density?

This is confusing to me: Since pressure increases with temperature (I don't know why), how can air density decrease with temperature. In a hot day then pressure would increase and air density ...
10
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2answers
6k views

How hot would pressurized air get if the air conditioning failed?

I understand that aircraft are pressurized by pushing air into the cabin using the engines, and using a valve to let the air escape at a controllable rate thus achieving the desired pressure ...
10
votes
2answers
651 views

Is it legal to fly GA aircraft in temperatures above what is shown on the performance charts?

Most Cessna aircraft have performance charts the range from 0 to 40 Celsius. I've had a CFI tell me that the FARs prohibit flight if the OAT exceeds 40C or whatever is shown on the performance charts. ...
9
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3answers
17k views

Cargo aircraft temperature [duplicate]

What is the temperature in the storage compartment on board of a cargo aircraft? I'm ordering a temperature-sensitive package by airmail and wouldn't want it to freeze. There are many questions ...
9
votes
3answers
2k views

How does latitude affect the air temperature at 8 km altitude where planes fly?

Is the air temperature (at 8km) above the North or South poles colder than the same altitude above the equator? Why? Ground level air temperature difference between coldest and warmest places on ...
9
votes
1answer
23k views

What appears on EGT Gauge if the mixture is rich or lean?

I have some questions on interpreting Exhaust Gas Temperature (EGT) readings. Can you give me some input on: What appears on EGT Gauge if the mixture is lean or rich? what is the normal range, ...
8
votes
1answer
652 views

Can heated air be provided in the cabin in commercial airlines?

Having travelled quite a number of times, there are times, when the cabin becomes a bit too cold, or people with certain condition get shivering quickly. In such circumstances and generally, is it ...
8
votes
3answers
374 views

Why is extreme cold weather a challenge at airports, since jets operate at extreme cold conditions in flight?

Wondering what specifically the issues are. Obviously, taking off and landing have more 'moving parts' but more curious about the actual extreme cold. I assume the operating temperatures at cruise ...
8
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1answer
2k views

What is the average temperature in the luggage hold of a passenger plane? [closed]

I am asking this seemingly odd question, as we'll have to transport some medicine in our luggage and it's supposed to be stored at temperatures between -8C and <...
8
votes
1answer
212 views

Why do different aircraft have different maximum operating temperatures?

I was reading this Wired article about the recent Phoenix heat grounding some jets. It's a great read on why heat is detrimental to lift, but it raises a point it never answers (emphasis mine) ...
8
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2answers
1k views

What is the difference between planned true airspeed and actual true airspeed?

My electronic E6B does calculations for both planned and actual true airspeed (yielding different results). I was told the difference has to do with assumptions about temperature, but the manual doesn'...
6
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3answers
2k views

If you depressurize an aircraft at FL340, will the temperature inside fall to match the temperature outside?

Assuming you’d have an oxygen mask on before hand, and you depressurized the aircraft at FL340, would the inside and outside temperatures quickly become the same?
6
votes
2answers
6k views

How can OAT and SAT differ?

From YouTube. I always thought SAT (Static Air Temperature) and OAT (Outside Air Temperature) were the same thing. So does this answer, so does Wikipedia: [The] outside air temperature (OAT) or ...
6
votes
1answer
280 views

What is the temperature of intake air at several speed of sound intervals from 1x to 10x?

I watched a YouTube movie about Reaction Engines development of the Sabre engine which main feature is cooling intake air. However, I cannot find an overview of the temperature of intake air at ...
6
votes
1answer
127 views

Why does the temperature rise in the boundary layer after a shock wave?

Is it because the BL thickens after the shock so the drag increases, causing a increased friction? Here M=0.82 far from the airfoil, the picture represents the static temperature in Kelvins around the ...
6
votes
1answer
2k views

What is the fuel temperature in the tanks during a flight?

I'm trying to estimate the temperature of fuel stored in wing tanks during the flight. In my situation, I'm considering two wing tanks of 2000 liters each, one on each wing, at 20°C before the flight ...
5
votes
2answers
964 views

Flex temperature isn't actually “fooling” the FADEC, right?

I'll be using Airbus terminology here because that's what I know, but I guess the concepts are universally applicable. The way I understand flex temperature is: It's a user interface for pilots to ...
5
votes
1answer
2k views

What is the temperature of the air leaving the combustion chamber of a CFM56-5C?

What is the temperature of the air leaving the combustion chamber of a CFM56-5C? I was wondering as I could only find out that the fuel burns at around 1500 Celsius but this can't be the same as the ...
5
votes
2answers
5k views

How to calculate outside air temperature at a certain altitude?

I am a PPL student and working on the cross-country planning. Let's say the OAT is -13º @ 6000', how to calculate the OAT @ 7000'?
5
votes
1answer
4k views

Why are min and max temperatures (TN TX) not published in TAFs in the United States?

I know that other countries like Brazil, Argentina, etc. do publish minimum and maximum temperatures in their Terminal Aerodrome Forecasts, abbreviated TN and TX. But why are they not shown in TAFs in ...
5
votes
1answer
4k views

What is the relationship between temperature, dew point and the formation of clouds?

What can you infer from the temperature / dew point values in this METAR? EGJG 121630Z 09012KT 9999 SCT006 15/14 Q1015 I understand the temperature is 15 degrees and the dew point is 14, and I ...
4
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2answers
282 views

Can the ECS work in an unpressurized cabin?

Can you control the cabin temperature if the cabin is unpressurized? What if the "cabin" isn't really that big, like a fighter aircraft? For example, could I cruise in comfort at 20,000 ft in an ...
4
votes
2answers
730 views

How do pilots calculate the temperature to put Into the FMS for an FLX takeoff?

I recently read an article about derated takeoffs and I understand the concept, but how do pilots know what temperature to put into their FMS if they want an FLX takeoff? Some people say it's a rough ...
4
votes
1answer
568 views

Who controls the cabin air temperature?

I understand the B737-800 has two air conditioning packs that handle the temperature of three zones: the cockpit, the fwd cabin and the aft cabin. I understand that which pack is turned on is ...
4
votes
4answers
11k views

Is there a maximum or minimum temperature for take-off and landing?

Is there a maximum or minimum temperature that a plane can take off or land at?
4
votes
1answer
238 views

How do airports in hot climates handle extremely high temperatures?

In June 2017 dozens of flights were cancelled in Phoenix, Arizona because of temperatures exceeding 120 degrees Fahrenheit/48.9 degrees Celsius.1,2 Hot air at a given air pressure is less dense, ...
4
votes
1answer
200 views

Where is the mistake in this air density calculation?

I intend to compute the air density, $\rho$ at an altitude of $h=15000ft=4572m$, with an ISA deviation of $\Delta_{ISA}=18^{\circ} F=10\,K$. Well I first computed the real temperature of the air at $...
3
votes
3answers
9k views

What effect does cold weather have on helicopter performance?

Recently I was flying around my RC helicopter on a 40 $^\circ$F (4$^\circ$C). At some point in the flight the rotor just stopped moving in mid-air and then I regained control back at ground level. I ...
3
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2answers
249 views

Can an S-duct fit a turbofan exhaust instead of the intake?

Can an S-duct fit a turbofan exhaust instead of the intake? The idea here is to merge 2 exhausts into one at the exact center of the tail. This would be for twin-engine aircraft that have both engines ...
3
votes
1answer
1k views

Am I correctly calculating the density altitude?

I came across the following question while studying for the FAA PPL written test: Determine the density altitude for these conditions: Altimeter setting: 30.35 Runway temperature: +25°F Airport ...
3
votes
1answer
537 views

Is airframe heating a concern at subsonic speeds?

It is a well-established fact that airframe and skin heating due to air friction is a significant concern with supersonic aircraft. However, below Mach 1 (i.e. typical commercial aircraft flights ...
3
votes
1answer
343 views

Is there an ideal air temperature for best performance in a light aircraft?

I know cold air is better for engine performance in general, colder air is also denser making lift components stronger(from what I understand). I was just wondering if there is a temperature or a ...
2
votes
1answer
169 views

Why Apollo 11 was launched in summer? (Performance question) [closed]

The question could seems stupid, but i think that best moment to launch a rocket is when temperature is lowest in order to achieve the best performance in a reaction engine. I do not know if there is ...
2
votes
1answer
158 views

What are the equation linking static air temperature with true airspeed & altitude?

If I want to calculate static air temperature (OAT), but I'm only given an altitude and a true airspeed. Is there such an equation that relates these principles together. I've had a look at wikipedia ...
2
votes
1answer
109 views

How hot is supersonic intake air?

How hot is the air at the compressor inlet at supersonic speed? For instance the Concorde at mach 2.2 or other jet engines at even higher speeds.