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Old 17th January 2003 | 18:48
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dynamite dean
25 Anniversary
 
Joined: May 2000
Posts: 326
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From: UK mainly
a question or two

I am having difficulty in finding an answer to this question....
I have seacrhed for it here but I find experts conflicting answers and in the process I have confused myself!

1. On the take off roll does EPR decrease or increase...and why ?

I think it increases because a jet depends on speed, temp and pressure but reading the tech forum search threads some people say increase and others say it decreases. The best one I have heard is that it decreases but due to ram effect thrust increases Please could someone explain to this piston pilot why? As I thought EPR is a measure of a jet engines power being developed. So this would appear to me a bit conflicting.

the next few I need a little assistance....

2.What are the effects of compressibilty - how do I answer this one?

3.what does cost index mean in an aircraft - does this mean how much fuel you are allowed to burn?

4.Could anyone tell me how an INS finds true north - Gyrocompassing?

5.What effects AoA at the stall - I didn't think that AOA could be effected at the stall only the speed

I have found answers to most of my questions but these residual ones have appeared!

Thanks Dynamite
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