dabkb2
Dave Bacon
- Joined
- Sep 26, 2005
- Messages
- 2,787
- Location
- Vista, Ca
- Aircraft
- Sport Copter Vortex 582, 2 KB2 90Mac KB3 582
- Total Flight Time
- 529 hours
Did not want to high jack Vance's thread, so I'll start this here.
Chuck said
Today, 07:56 AM
C. Beaty
Gold Supporter
Join Date: Apr 2004
Location: Florida
Posts: 7,021
--------------------------------------------------------------------------------
The story is different when performing slow flight in a nose high attitude at high power.
Then, the propeller thrust line is no longer parallel to the flight path.
In level flight with a nose high attitude, the vertical component of propeller thrust unloads the rotor. It becomes the product of propeller thrust and the sin of the angle.
For example, with a noseup angle of 30º and 400 lb. of propeller thrust acting on a machine of 500 lb. AUW, the vertical component of propeller thrust is 200 lb. (sin 30º = 0.5) and the remaining rotor load drops to 300 lb. Rotor RPM drops to (300/500)^0.5 = 77%.
That’s dangerous.
-----------------------------------------------
In ground effect I can fly slow, 10knt, nose high for extended periods of time with no problem. I tryied that at 500' and will not do that again. It is obvious to me that Ground Effect does effect the rotor, or have I missed something? Just trying to keep myself out of trouble.
Chuck said
Today, 07:56 AM
C. Beaty
Gold Supporter
Join Date: Apr 2004
Location: Florida
Posts: 7,021
--------------------------------------------------------------------------------
The story is different when performing slow flight in a nose high attitude at high power.
Then, the propeller thrust line is no longer parallel to the flight path.
In level flight with a nose high attitude, the vertical component of propeller thrust unloads the rotor. It becomes the product of propeller thrust and the sin of the angle.
For example, with a noseup angle of 30º and 400 lb. of propeller thrust acting on a machine of 500 lb. AUW, the vertical component of propeller thrust is 200 lb. (sin 30º = 0.5) and the remaining rotor load drops to 300 lb. Rotor RPM drops to (300/500)^0.5 = 77%.
That’s dangerous.
-----------------------------------------------
In ground effect I can fly slow, 10knt, nose high for extended periods of time with no problem. I tryied that at 500' and will not do that again. It is obvious to me that Ground Effect does effect the rotor, or have I missed something? Just trying to keep myself out of trouble.