Two question referring to aircraft performance

[Norbert Pürringer]

Hello,

please help me finding an adequate answer to following questions being
possible examination questions:

-) When an aircraft climbs, its performance changes: How and why?

-) Explain the performance limits valid for any aircraft

Thank you,
Norbert

[Blanche]

Post by Norbert Pürringer
please help me finding an adequate answer to following questions being
-) When an aircraft climbs, its performance changes: How and why?
-) Explain the performance limits valid for any aircraft

Unfortunately, these days the performance limits are declared (note: I
wrote declared and not defined) by the lawyers.

However, there are a few really good books on the subject aerodynamice
(which really is nothing but the study of performance). You may find
them in the local library:

Flight Theory for Pilots
Aerodynamics for Naval Aviators (not at all simple!)
Advanced Pilot's Flight Manual (William Kershner)

The first 150 pages of Kershner's book is nothing *but* performance.

In brief:

"An airplane's rate of climb is a function of excess HP (horsepower)
available. This can be approximated by:

rate of climb (fpm) = (ETHP * 33,000) / weight

where ETHP is excess thrust horsepower

And altitude & density altitude get involved, too. Increased altitude
means decreased HP. Rule of thumb is 3% per thousand feet. Hence a C172
with a 180 HP engine will only be able to produce 30% of that HP at
10,000 ft, or 127 HP.