What is a unit of AoA?

[nittany03]

And even that isn't standard. T-45 stalls at ~26 units clean and 29-30 dirty. No auto-flap-recalibration gizmo.

 

[MasterBates]

About the whole AOA thingie. While we do not have that, they do not have to deal with:

Retreating Blade Stall
Vortex Ring State
Translational Lift
Gyroscopic Precession (pretty well mixed out of the 60, unless you droop bad)
Drooping turns (loss of rotor RPM)

Also, instrument flying on a helo is mostly by performance instruments. When your "wing" (rotor disk) is not rigidly attached to the airframe, Airspeed/Attitude/Power combos are not neccisarily going to work. There are some that obvously will result in something you want, like and ITO (100-106% Torque, Wings level, 5-10 degrees nose down out of a hover will climb and accelerate)

 

[TurnandBurn55]

Just remember... make indexer go amber donut

Mmmm... amber donut...

 

[Schnugg]

Retreating Blade Stall Vortex Ring State Translational Lift Gyroscopic Precession

Sounds like a bad episode of Deep Space Nine.

Hey wait a sec...every episode of that crappy show was bad....

 

[squeeze]

Bah... AOA doesn't really matter below 30 kts.

 

[nittany03]

i vaguely remember hearing something about 112.4% +/- 4??? i think that's the egt/rpm light...

That's N1 RPM, not N2 RPM . . . there is no gauge for the N1 compressor . . .
And thank you for letting me exercise my inner systems geek. :icon_tong

 

[Chubby]

That's N1 RPM, not N2 RPM . . . there is no gauge for the N1 compressor . . .
And thank you for letting me exercise my inner systems geek. :icon_tong

Well if we are really going to get in the weeds then ... its 112.4 +/-1%.

HA, I win!

 

[Cadwallader]

Here's a good article on the basics of AOA...

http://www.planeandpilotmag.com/content/2006/may/angel_of_attack.html

 

[Tom]

Well, not quite

AOA stands for Angle of Attack. If the unit for the T34 is 29.5 then the Critical AOA (angle at which the aircraft will stall [stop producing lift]) is 29.5 degrees. The AOA is the angle between the chord line and the relative wind. Chordline being an imaginary line drawn from the leading edge of the wing to the trailing edge (front to back).

While you can change the AOA in flight you cannot change the Critical AOA (the airplane will always stall at 29.5 degrees)

*This is assuming the military measures the same as civilian.*
Hope that helps.

The critical angle of attack is the point at which the coefficient of lift is reduced greatly. Notice how the curve gradually shifts downward. If lift was not produced it would be zero. Lift is still produced. If you don't believe me, think of it this way. If lift was no longer produced, why don't you accelerate downward towards the Earth like a sky diver?In a GA aircraft, a stall performed correctly results in a minimal loss in altitude. Now, given military aircraft and other aircraft designed for faster speeds they will probably lose more altitude.

As you can see, if Cl was 0, the enitre equation would equal 0, meaning 0 lift. This may sound frivilous, but I consider it to be important. Nanner nanner boo boo.