Expert: Mark Janus - 3/23/2008

Question
i am training on cessna aircraft. I don't understand when someone says the aircraft is old or the engine is old, therefore its unable to climb i.e climb rate is slow , when it pitch/climb at Vy airspeed.
what i know is that aircraft performance is due to the airspeed over the wing and its angle of attack or the pitch.
If the speed on the airspeed indicator is indicating Vy, it should performed the same whether its an old or new.

Answer
Sorry for the delay....  I had some trouble getting on to the AllExperts site....

I don't consider myself very knowledgeable of flight mechanics (of which this is a question), but I'll give a stab at answering your question....

an older aircraft (engine) will not produce as much Hp as a newer one, the equation determining the best rate of climb involves the thrust, drag,flight angle, and weight....   for an older aircraft the drag is probably slightly higher, the thrust is probably slightly lower which will result in a slightly lower rate of climb....

What you are leaving out is the flight angle, which I believe would be much shallower for an older aircraft due to the thrust and drag points I've already made....

Thanx,
mj