imsofaman
Senior Heliman
Location: Northern NJ
My Posts This: Topic Forum | Jodini,
First, make sure your hang angle is per the instruction book from A of A. I have heard the Areobalsa blades creat a huge amont of lift, so if the A of A blades are flat bottom with the Clark Y on top ....the mast would be set for an aggressive lift angle. If you add the Areobalsa blades without changing the head angle, I am sure it did a loop! BUT....fist things first...let's start from the beginning.
With the original blades, you had experienced rotor stall and the gyro rolled the the side and crashed? I looked at your photos, hard to see if you have enough neg. pitch on the trailing edge. If there is not enough, the blades will never get to full autorotation speed, thus never creating any lift.
Blade Stall:
The Clark Y produces the lift just like a wing, with a plane, I am sure you have experience a tip stall with a fixed wing aircraft?
If the gyro's rotors are not spinning fast enough and too much throttle is applied...the same thing happens, rolls to one side and it crashes.
You have to remember that if the blades are stalling, just because you goose the throttle, that is not going to bring the blades to speed in less than a second. Increasing the throttle actually makes it worse because it wants to make the gyro lift and take off prematurely.
It takes a few seconds in a stiff breeze to get full autorotation. At a certain altitude you could get away with it, but being so close to the ground, you need more toime to get the blades spinning.
Are you hand launching it? That is by far the best way to take off. ROG is difficult with a fixed head autogyro because the angle of attack when the gyro in on the ground is so great.....as you roll down the feild, it will want to take off BEFORE the blades are at full rotation which will result in the bird rolling to the side, and nothing will stop it...splat!!!! Blade stall.
Here are my suggestions. Using the Aerobalsa blades, you may want to decrease the head angle. Before you do that, take the gyro out on a breezy day. Start the motor, adjust the throttle to half or maybe a little more. Hold the Gyro in your hand and tilt it back so the wind is hittng under the rotors making them spin. Once they are spinning hold it over your head like you are going to throw it. Make sure the blades are at full rotation, you can hear and feel it. Try to make a mental note of what kind of pull it is producing. This should be the light cruising speed or just enough throttle to keep it floating. Now if it feels like it just wants to rip out of your hands.....you need to change some things. It should produce a decent pull, enough to lightly lift the gyro out of your hnds if holding it loosely. If it has too much lift, like you have to have two hand to hold it, there is a problem. You should be able to let it fly in your hands lightly holding it. You should be able to trim it out by holding lightly...letting go periodically, let it fly in your hand, testing the trim settings. Make sure your down thrust is correct. Try trimming the elevator down and try the process again. If that does not work....put the elevator back at the nuetral position. Try decreasing the head pitch with washers under the rear of the gear box. Hold it in the breeze again....the extreme pull should change at some point.
I ALLWAYS trim out the model with this hand held method. You get a better feel for it instead of just throwing it blind and hoping for the best. I have heard a lot of great things about the C4 model, it will fly. You just need to fine tune it a little more.
Hope this helps,
Dave Surace |
