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RV-9A flap push rod

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Oldgeezer

Active Member
Does anyone recall how much of each end of the VA256 hex pushrod they had to cut off to make the proper length? Also , what is the best method to open the exit hole? ie. start with the flap all the way up or midway? The plans call for a total bearing to bearing length of 6 5/8 in. How much bearing thread needs to be sticking out each end of the rod?
Thanks in advance
Oldgeezer
RV9A
 
push rod

What Dr Cleve did is use the full size drawing on the plans. We laid the rod end bearings over the drawing as drawn, lined up the hex shapped push rod with the same amount of thread inserting inside the rod. With the center of the 2 bearings spaced as required, and the same amount of thread inserted as shown, we cut the rods to this length.
 
sportpilot said:
What Dr Cleve did is use the full size drawing on the plans. We laid the rod end bearings over the drawing as drawn, lined up the hex shapped push rod with the same amount of thread inserting inside the rod. With the center of the 2 bearings spaced as required, and the same amount of thread inserted as shown, we cut the rods to this length.
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Claude
My plans do not show a full size drawing.
 
Flap pushrod

Called Van's and Gus described the method for determining the proper flap rod length which is not written in the building instructions. 1st align the flaps in the up position, level with the ailerons rigged at neutral and the flap motor in the full up position. Then cut off the VA256 hex rod to get the proper length. He said the geometry of the attachment point will determine the amount of flap down deflection.
Does anyone know if there is a maximum down deflection on the RV9. The book says 40 deg for the RV7 and 32 deg for the RV9 I am getting 40 - 41 deg down on my 9. Not sure if it has to be limited to 32 deg or just go with what I can get. Any thoughts or others experiences?

Oldgeezer
RV9A
 
I haven’t installed the flap and linkage yet but I am sure the limit on both ends of the flap position must be determined by the limit of the flap position motor and worm drive. If you were to try and limit the travel of the flap by some stop, short of the motor and worm gear travel, the motor would stall when it hit the stop rather than slip or clutch at the end of the worm gear as it is designed to do. I’m surprised there is such a difference between the book recommendation, 32 degrees and your actual movement, 41 degrees. I don’t see anyway to reconcile the difference other than changing the geometry of the flap system which I’m sure Van does not expect builders to do. I wonder what Van has to say regarding this disparity?
 
Oldgeezer said:
Does anyone know if there is a maximum down deflection on the RV9. The book says 40 deg for the RV7 and 32 deg for the RV9 I am getting 40 - 41 deg down on my 9. Not sure if it has to be limited to 32 deg or just go with what I can get. Any thoughts or others experiences?

Oldgeezer
RV9A
Click to expand...
Something is not right. The flap motor should limit the flap travel to about 32 degrees. Are you measuring the travel? (difference between the up and the down position)

Fin 9A
 
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Finley Atherton said:
Something is not right. The flap motor should limit the flap travel to about 32 degrees. Are you measuring the travel? (difference between the up and the down position)

Fin 9A
Click to expand...

I believe I know what I did wrong. I zeroed my digital level with the longeron with the fuselage level and then proceeded to read the flap deflection in the full down position and came up with 40-41 degrees. Correct me if I'm wrong, but I should have zeroed my digital level on the flap in the full up position and then lowered it to it's full down position and that would be the true degree of deflection. In that case it would be about 32 degrees. Does this sound right? Not much guidance in Van's instructions.
Thanks
Oldgeezer
 
zero up

Thats correct, zero up on the flap, then lower the flap to read the degrees of travel. If you have electric flap control you can check the deflection at each increment 10, 20 and 30. good job..:D
 
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