Netters
Lets make this really simple:
Angle of attack is the angle created between the chord line and the
relative wind. Period. The chord line is an imaginary line that we create for
discussion of the characteristics of a wing and is from the center of the
leading edge to the center of the trailing edge if viewed from the end of the
wing tip looking towards the fuselage. The relative wind is NOT the direction
of the wind blowing at the aircraft at a given time, nor is it the direction of
travel of the aircraft. It is the direction of airflow just before it begins
passing over the wing at the leading edge. It was correctly stated earlier
that the aircraft stalls at the same angle of attack for a given wing no matter
what the flight attitude, and that is true. This angle is known as the
critical angle of attack, and this does not change for a particular wing. If
we are in cruise climb, the angle of attack is small because we are using
surplus power to provide more thrust thean we need for level flight and we have
pointed the nose up in order for the wing to make more lift than is necessary
for level flight, which is increasing the angle of attack.
What must be understood is that when we test our KRs for the stall speed
from straight & level flight, whether power on or off, we are not pulling any
Gs to speak of, barely over 1G if that. However, lets say we are performing a
steep turn and allow the angle of BANK to roll on over to 60 degrees. All
aircraft regardless of make will experience 2Gs. This increases the wing
loading AND RAISES the stall speed of the aircraft because the effective weight
that the wing must now keep in flight is twice what it was in level flight.
That changes the critical angle of attack for that wing loading, referred to as
an accelerated maneuvering stall. Finding the correct location for a stall
warning device is not just picking an arbitrary point on the wing, and as Dan
stated, bad information is worse than no information.
The Pilots Handbook of Aeronautical Knowledge is not the most exciting
reading, but should be a must for all pilots who are thinking of flying their
own aircraft, or flying period. It is also good to read the Airplane Flying
Handbook. Both are in expensive, under $16 and full of a wealth of flying
knowledge that will prevent you from falling prey to the "well that is what
this pilot told me" syndrome. Many many accidents and incidents with aircraft
would have been prevented if pilots had just read first about what they were
doing instead of trying to learn OJT!
Colin & Bev Rainey
KR2(td) N96TA
Sanford, FL
crain...@cfl.rr.com
http://kr-builder.org/Colin/index.html
