What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

RV 14 '0' degree flap speed ?

barryrv10

Well Known Member
Does anyone know what the flap speed is for the out of reflex '0' degree position? The RV10 has a higher speed for '0' degree than the the top of the white arch speeds for the rest of the flap positions. Thanks Barry
 
Does anyone know what the flap speed is for the out of reflex '0' degree position? The RV10 has a higher speed for '0' degree than the the top of the white arch speeds for the rest of the flap positions. Thanks Barry

I believe Van's has recently clarified that there is no longer a speed restriction for the 0* flap position on the RV10. Would assume the same applies to the 14. It always seemed odd to have a speed restriction with a neutral flap.

Larry
 
I believe Van's has recently clarified that there is no longer a speed restriction for the 0* flap position on the RV10. Would assume the same applies to the 14. It always seemed odd to have a speed restriction with a neutral flap.

Larry

I believe this is correct. However, the original limit didn?t seem odd to me. Full up, the load is carried by the hinges and the aft spar. In trail, the smallish actuating arm carries some of the load. So, at a minimum, it would have required some engineering to determine if the strength was there.
 
I believe this is correct. However, the original limit didn’t seem odd to me. Full up, the load is carried by the hinges and the aft spar. In trail, the smallish actuating arm carries some of the load. So, at a minimum, it would have required some engineering to determine if the strength was there.

not an aerospace engineer, but I would expect no load on a flap or elevator that is "in trail" or 0* Maybe I have more to learn in this area. On my 6, the ailerons naturally find an in trail or 0* position. I would expect more load on the actuating arm at -3 than 0

Think about the ailerons. In neutral, the stick is dead, no load or resistance. If I move the ailerons to -5/+5, I feel resistance on the stick. They want to go back to in trail, which to me means less load on the control rods attached to them when neutral.

Larry
 
Last edited:
not an aerospace engineer, but I would expect no load on a flap or elevator that is "in trail" or 0* Maybe I have more to learn in this area. On my 6, the ailerons naturally find an in trail or 0* position. I would expect more load on the actuating arm at -3 than 0

Think about the ailerons. In neutral, the stick is dead, no load or resistance. If I move the ailerons to -5/+5, I feel resistance on the stick. They want to go back to in trail, which to me means less load on the control rods attached to them when neutral.

Larry

The ailerons have a perceived zero load at zero deflection because they are linked together left and right. If you disconnected them, they would both float upward to some angle, maybe -5 degrees or so?. The RV-10 and 14 flap has less lift load on it at -3 than it does at zero deflection. But the loads at zero are small enough that if Van removed the distinction, it means the linkage is strong enough to hold the flap at zero up to Vne, which I think is extremely likely.
 
The ailerons have a perceived zero load at zero deflection because they are linked together left and right. If you disconnected them, they would both float upward to some angle, maybe -5 degrees or so?. The RV-10 and 14 flap has less lift load on it at -3 than it does at zero deflection. But the loads at zero are small enough that if Van removed the distinction, it means the linkage is strong enough to hold the flap at zero up to Vne, which I think is extremely likely.

What Steve Said ^^^^^^^

The ailerons on all the RV's return to neutral because they are linked together and the the forces on each cancel the other (except when they don't... which is why adjusting the aileron shape can fix a roll imbalance issue).

A strange thing that has been discovered about the RV-10/14 airfoil after quite a few years of experience with it at this point......

In high speed one G flight, there is actually a very slight downward load on the ailerons (and presumably flaps when they are in the -3 degree reflex position) so at this point I am not sure what the ailerons would do if they were disconnected, but we do know that at either -3 or zero degrees, the loads are low enough that the Vfe limit does not need to be applied.
 
Last edited:
How much reflex (how negative can you go) on aileron adjustment before the frise aspect starts causing drag?
 
The ailerons have a perceived zero load at zero deflection because they are linked together left and right. If you disconnected them, they would both float upward to some angle, maybe -5 degrees or so?. The RV-10 and 14 flap has less lift load on it at -3 than it does at zero deflection. But the loads at zero are small enough that if Van removed the distinction, it means the linkage is strong enough to hold the flap at zero up to Vne, which I think is extremely likely.

Thanks for educating me. Much appreciated.

Larry
 
How much reflex (how negative can you go) on aileron adjustment before the frise aspect starts causing drag?

The RV-14 (and RV-10) have airfoil sections that were specifically designed to have a reflex shaped into the trailing edge portion. That shape is incorporated into the shape of the ailerons, so there is no drag issue.

Reflexing the ailerons on the other RV models would probably produce no speed benefit because the airfoil was not designed for it, and it like would induce some drag (and potentially control feedback issues) for the reason you mentioned.
 
Back
Top