# Questions tagged [temperature]

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

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### What temperature is the vapor that forms around a maneuvering aircraft?

At what temperature does the vapor seen on aircraft maneuvering form? I know this highly depends on humidity, but is there a general calculation? When doing my research, I found this page, but it ...
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### How is the pressure constant across the boundary layer but density isn't?

In $P=ρRT$, ρ is density, R is the gas constant, and T is the temperature in Kelvin. In the boundary layer, the temperature and density varies, so why doesn't the pressure? If you have a slip line in ...
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### Does one need to make temperature corrections for airspace avoidance?

This answer claims that airspace boundaries are based on true altitudes, not any particular altimeter setting. But temperature errors can cause indicated altitudes to vary wildly from true altitudes. ...
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### Are cabin temperatures related to destination weather?

I've been in a long-distance flight between northern and southern hemisphere, with temperatures nearing 5°C on the origin, and 25°C on the destination. During the first flight, the cabin was ...
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### What is the general operating temperature of Free Piston Turbine Engines?

The turbine in turbine engines can face temperatures from the combustion chamber up to 1700ºC, but I can't find any information on the operational temperature of free piston turbine engines. I'm ...
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1 vote
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### Air pressure in cold air vs warm air

I’m a little confused here . Studying for ppl exam it is stated that cold air is at higher pressure than warm air rising up, so the flow is from cold to warm. But then again , when flying from warm ...
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### The phase having the hightest TIT for a flight mission

I have a query concerning the turbine inlet temperature (TIT) in the context of various flight mission phases. Specifically, I'm trying to ascertain at which phase the gas turbine reaches the highest ...
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### How can TAS be calculated from indicated temperature and Mach number? [duplicate]

Situation I am working on programming my own E6B while I learn more about aviation, but I have run into some confusion. Two pairs of the equations are very similar except for using true or indicated ...
323 views

### Is there a certain minimum temperature we need to turn on pitot heat on light trainer aircraft (eg DA40NG)?

Is there a certain minimum temperature we need to turn on pitot heat on light trainers (eg DA40NG)? In the AFM and checklist documents for the DA40NG, information is given that it should only be ...
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### What are the exit temperatures of bypass flow

Consider a typical high bypass turbofan designed for cruise at approximately mach 0.8, with a separate nozzle for the bypass air. Ideally, the bypass air would be compressed adiabatically by the ...
1 vote
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### Which aircraft has the highest minimum operating temperature?

Aircraft often have a minimum operating temperature due to fuel, oil, engine, and other limitations. Which aircraft has the highest minimum operating temperature, and why? I'm looking for something ...
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### Why was the SR-71 made of titanium?

The temperature of the Lockheed SR-71 Blackbird's fuselage never exceeded 500 Celsius, which, to my knowledge, would be perfectly tolerated by stainless steel. So, why titanium?
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### Why are the brake temperatures so high during the cruise?

While monitoring the A320 aircraft systems during cruise I noticed that brake temperatures are relatively high compared to the OAT. I have seen brake temperature indications range between 20°C and 120°...
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The standard question on a knowledge test: "Under which condition will pressure altitude be equal to true altitude?" The answer is: "when atmospheric conditions exist, i.e., 29.92" ...
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### How to calculate the TAT (total air temperature) when a rocket is flying to space? [closed]

I checked this answer and I used the formula this answerer provided, but I couldn't get the data he/she presented in the graph. Did I do something wrong?
277 views

### Is the ISA still up to date?

The Standard Atmosphere dates back to 1962 when Earth was colder. The 1976 update didn't make changes within 50 km altitude (the tropo- and stratosphere). It assumes 15°C at sea level, decreases until ...
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### Does a plane's service ceiling vary with season/temperature?

Aircraft use barometric altitude, e.g. FL300 is the barometric altitude of 30,000 ft MSL. In winter however, FL300 is actually lower than the absolute altitude of 30,000 ft because of a cold and ...
320 views

### Cessna 182Q (parachute operation) - climb leaning with CHT

for a 182Q the POH specifies for maximum climb to use 2400 RPM and full power with given speeds (78 KIAS for Sea Level, reducing to 72 at FL100). It specifies that the mixture may be leaned at 5000ft ...
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### Temperature profile for a boundary layer

So I was reading the textbook today, and I see this picture for the temperature profile through the boundary layer. And I was confused on why the shape looks like this? Should it not look more like ...
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### Would building a large asphalt square or painted dark black area create a "thermal generator" for glider use?

Imagine if you build a "parking lot" square of asphalt and paint it the deepest black possible to absorb maximum heat...would that spot essentially be a thermal generator that you could fly ...
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### Will a jet flown on a parabolic arc reach its highest altitude on a warm day or a cold one?

In level flight, on cold days jet-powered planes can fly higher because the air is denser. However, at the same time the true airspeed is lower because of the denser air. At warmer temperatures a ...
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### How do jet engines cool the gas in the combustion zone?

The adiabatic flame temperature of kerosene in air is 2093 C (source). Modern jet engines have a turbine inlet temperature (TIT) of 1700 to 1800 C. This is the max acceptable temperature before the ...
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### If absolutely nothing changes except temperature, does indicated altitude increase, decrease, or stay the same?

I have gotten conflicting answers from CFI's on this one. In bold are the only things that changed or would potentially change. Initially: Aircraft is parked at a very dry (to factor out humidity) ...
2k views

### How much aerodynamic heating do jetliners endure?

At cruise altitude (~ 33,000 ft) and cruise airspeed (~ 500 mph) how much do present-day airliners heat up due to air friction during their journey? Probably not much because there's still ice on the ...
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### Why doesn't temperature affect Pressure Altitude?

In this picture: it states the tops and bottoms of the 3 columns of air have the same pressure. This explains the error in altitude indications given in a non-standard temperature. Pressure only ...
1 vote
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### What is a typical fuel temperature entering the burner for different mission flight points of a civil aircraft?

Is there a target regarding the fuel temperature that enters the turbine engine's combustion chamber and if so does it change with different operation flight points in civil aircraft applications? Is ...
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1 vote
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### What is a typical range of air temperature used for engine inlet cowl anti icing?

So i was searching the internet for engine inlet cowl anti icing and found that usually compressor bleed air is used to prevent the ice formation in several parts of the aircraft. I am mainly ...
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1 vote
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### Why does the CRJ100/200’s FMS miscalculate temperatures at altitudes in excess of 36k feet?

The CRJ100/200’s flight management system (FMS) apparently is not to be used to calculate engine thrust settings when the aircraft’s altitude exceeds 36,000 feet, due to internal calculation errors at ...
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### What weather should we expect when temperature and dew point are similar?

What should i expect during my flight planning when i see both temperature and dew point are the same? I understand there will be fog but what else? could it mean icing? any difference between 20/20 ...
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### What is the relationship between fuel mixture, throttle setting and engine temperature?

I'm trying to understand the relationship between mixture, throttle, and engine temp. In this article from AOPA, it states ... a lean mixture of 16 to 1 is not going to burn as hot as a rich mixture ...
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### In a B737 NG, when a TO is flown with an Assumed Temperature N1, is the subsequent CLB N1 also adjusted (lowered) accordingly?

The Title is my question. Because I think that if one uses a very high Assumed Temperature, the subsequent Max CLB N1 maybe higher that the TO N1.
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### How can I work out Sea Level Pressure from QNH?

I am a little confused, is the QNH the current pressure at Sea Level? Therefore putting it into the altimeter will give your current altitude on the ground in pressure altitude relative to current sea ...
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### What do these temperature data listed in the EASA Type Certificate Data Sheet mean?

Could you tell me what is the Maximum Permissible Indicated Turbine Temperature (ITT) and the ambient limit temperature for sea level static thrust?
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### What can cause the engine temperature to be high in piston engines?

What can cause the engine temperature to be high in piston engine aircraft?
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### 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 ...
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1 vote
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### What is the speed above which painting an aircraft black (or dark) results in lower skin temperature?

The Concorde is painted white for thermal reasons. If I understand correctly, it is done to reflect as much radiation as possible in order to lower tempereture. But when the skin is really hot (SR-71, ...
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### 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.
1 vote
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### What happens to the dynamic temperature in the boundary layer at supersonic speed?

In the boundary layer for a supersonic flow, does the dynamic temp decrease? Thank you
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### 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 ...
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### 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 ...
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### 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, ...
3k 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?
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### 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 ...
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### Why and how do atmospheric properties sometimes vary from the ISA? [closed]

I'm curious as to why sometimes atmospheric properties don't match the ISA's. One reason I am considering is due to calibration discrepancies. By atmospheric properties I mean temperature, Density, ...
771 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 ...
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### How can I calculate turbofan efficiency as a function of turbine inlet temperature?

I know that increasing the turbine inlet temperature (TIT) increases the overall efficiency of the jet engine. So I wanted to find the overall efficiency as a function of TIT. I used the equations ...
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### How to compute the change in static temperature using only altitude?

I'm given an initial altitude of FL290 in ISA conditions, and the aircaft is said to climb to reach FL310. How can I use this to calculate the change in static temperature between the two flight ...
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### 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 ...
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### 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 ...
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