TR UAV/UCAV Programs | Anka - series | Kızılelma | TB - series

[Yasar_TR]

Does 2 F110 engines on lower output have a less infrared signature than a F35 engine on higher output?

According to unconfirmed sources :

F110
non afterburner/dry exhaust temperature : 600-700 degrees C
Afterburner exhaust temperature : 1700-2000 degrees C

F135
non afterburner/dry exhaust temperature : 600-650 degrees C
Afterburner exhaust temperature : 1500-1700 degrees C

So in reality there isn’t much between them.

It depends on how well the aircraft disguises IR picture of engines is what matters.

In essence these values vary a great deal depending on RPM of engines and the length of time afterburners are applied

An aircraft’s skin temperature goes up drastically with its speed and altitude. At Higher altitudes air is thin the friction is less. Hence less heat develops .
But at higher altitudes planes can go faster. This increases friction and skin temperature climbs.

At mach2 and high altitude the skin temperature can be between 120 to 180 degrees C

I always remember the Russian IR picture of an f22 from 150km away.

 

[TheInsider]

I found the exact values for F110 it is 482 degree celcius 10 feet away from the nozzle and 935 degree celcius when measured from the exhaust thermocouple(inside the engine just before the afterburner), both at military power. Admittedly second figure is more useful considering the IR signature.