View Full Version : Rotor Thrust
11-02-2003, 01:33 PM
Alright! *I'm pulling my pants down. *<br><br>I understand the advancing blade, retreating blade, and hinging such that we get equal lift.<br><br>I don't understand how a non powered rotor produces rotor thrust. *Or how the rotor spinning is producing thrust? *Am I missing the relationship between lift and thrust? What is Rotor Thrust?<br>
11-02-2003, 03:10 PM
John,<br><br>for these kinds of questions we need people like Chuck Beatty and Doug Riley. I haven't seen them here yet. Quick, somebody go get them!! ;D
11-02-2003, 06:00 PM
John, untill we get the big guns here, rotor lift and rotor thrust for all intents and purposes are the same.<br><br>Aussie Paul.
11-02-2003, 08:25 PM
John,<br>You are right in your asumption that a non-powered rotor cannot produce thrust. However in our case the rotor is powered by inflow of air, from below the blades (autorotation). <br>Being powered, the rotors are just as capable of producing thrust as a propeller.<br><br>Regards Tim McClure
11-03-2003, 07:09 AM
(Just a reminder, I'm a newbie and a little simple, but I've doing a lot of reading on the sites so...) I thought that the gyrocopter rotor produced LIFT not Thrust ???. Thrust comes from the engine/propeller, yes? no? This is not a helicopter which has to do both with the rotor, right?
Don't confuse Lift with Thrust. *Thrust is a force produced by a propeller (or by jet for that matter). *Both your engine propeller and your rotor are producing thrust. *The engine thrust is pushing you forward, and the rotor thrust is pulling you up and a little backwards.<br><br>Lift is the vector of the rotor thrust, which is opposite to gravity. *The rotor thrust line, which is tilted a little backwards in a gyroplane, can be divided into two "imaginary" vectors: Lift and Drag. *<br><br>The rotor achieves rotation by the air flowing through it. *The rotation itself is producing thrust, just like any other propeller.<br><br>Udi<br>
11-03-2003, 11:15 AM
Thanks All,<br><br>The whole world makes sence again ;D<br>
11-03-2003, 11:38 AM
Udi has it "nailed."<br><br>Also, remember that the rotor thrust line (vector) is always perpendicular to the rotor tip plane.<br><br>So, when you read a post by Chuck B. or Doug R., etc, and they mention the relationship of the rotor thrust line to the CG, you'll know what they are talking about.<br><br>Also, please don't pull your pants down. "Homey don't play that."
03-14-2004, 08:41 AM
Can't see how it works?
An easy way to visualize how a "driven" gyro rotor produces "thrust" is to see the air moving up through the center portion of the rotor (inner 2/3rds of the blades) causing the blades to turn like a windmill. Then the outer portion (outer 1/3rd), that is going much faster, is being turned by this inner area to produce thrust just like a helicopter by pushing the air down.
Center portion being driven by the air (no thrust). Outer portion being driven by the inner portion producing thrust.
The 1/3rd point is not an abrupt change. It is just that the outer few inches are really turning fast and producing a lot of thrust and it becomes less and less as the point moves inward towards the center until at about the 1/3rd point it stops producing thrust and from that point in it starts to act more and more as a windmill to turn the rotor blades.
03-15-2004, 11:16 AM
Next time your out flying, pick out a grassy area that had been mowed 2-3 days before or a nice dry dirt (dusty) spot & make a zero roll landing.
You won't like all the dead grass clippings and/or dust getting all over you and your pretty gyro. Where did all that downwash come from?
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