Blade flapping

[David]

I have a question regarding blade flapping, the definition of it is as follows:

Blade Flapping is the up and down movement of a rotor blade, which, in conjunction with cyclic feathering, causes Dissymmetry of Lift to be eliminated.

The advancing blade, upon meeting the progressively higher airspeeds brought about by the addition of forward flight velocity to the rotational airspeed (of the rotor), responds to the increase of speed by producing more lift.

The blade flaps (or climbs) upward, and the change in relative wind and angle of attack reduces the amount that would have been generated.

This definition was obtained from the following web address:
http://www.dynamicflight.com/aerodynamics/flapping/

My question is: is blade flapping a common problem encountered or is it something that you just have to be consciensously aware of as forward velocity increases? Also I am not very sure what the current Army rotor blades are made out of, but would it help at all to place lead weights at the tips like they do on the carter copters? I'm just curious, because they have been having good results with this. Thank you for your help.

V/r
David

[flyuh60]

Blade flapping is not a problem it is a function of the rotor system that is built into the aircraft to help eliminate dissymetry of lift. Dissymetry of lift is the difference in lift between the advancing and retreating side of a rotor blade. Lets say the rotors spin at 100mph at the tip and you are flying at 50mph the advancing blade is actually traveling through the air at 150mph and the retreating blade is traveling at 50mph. The advancing blade is moving faster so it creates more lift. If the blades were not allowed to flap up and down the helicopter would roll over to the retreating blade side. Rotor blades are weighted at the tips and various other places throughout the length of the blade. Cyclic feathering is basiclly you as the pilot moving the cyclic either left or right to keep the helicopter upright. All of this stuff is not really something you have to keep in mind while flying blade flapping just happens automatically it is built into the design of all rotor systems. Cyclic feathering the pilot will do subconciouslly you'll move the controls to stay going straight and upright. When you get to flight school they will cover this in much more depth and you will have a good understanding of it. I just kinda put it in everyday language and made it simple. Hope this answers your questions. Let me know if you have any more. Also you can check out www. aviationtrainer.com it is a website put out by one of the IP's at the Army flight school good study material.

Mike