View Full Version : TAS VS IAS
schlarpa
11th Sep 2001, 07:21
Some boffin out there explain to me why aircraft become unstable when flying up high. And please don't say because of the difference between tas and ias. I want an explanation.
Genghis the Engineer
11th Sep 2001, 12:56
Perhaps you could be a bit more clear about your question.
G
CaptainSquelch
11th Sep 2001, 16:33
I'm not sure if I'm your type of "Boffin" but my aircraft does not become unstable when flying up high. At least not untill reaching FL 410. Not on Autopilot and not in manual flight. It does get a bit sensitive when flying manual but that is due to the high speed (I won't say wich one).
Sq
Capt Scribble
16th Sep 2001, 22:27
The inertia in the ac is related to TAS but all the damping and other factors that you learn about that make ac stable, such as the fin, are affected by the IAS. Therefore, at height, lots of inertia, but not lots of damping. There could also be instability arising from shock waves forming unevenly on each wing, but that's another story.
Perhaps he/she should purchase...Handling The Big Jets (Davies)....then he/she? might understand. Newer jets do NOT have the problems that older jets had, especially the early Boeing 707's. READ, and ye shall learn!
[ 17 September 2001: Message edited by: Checkboard ]