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RV-3 Drooping Ailerons

C

Chris Santschi

Active Member
Anybody have any information on the setup Van used on the first RV3 that used a lever at the base of the control stick that by moving it 180deg would cause the ailerons to droop 18deg. I read a report that said it would cause a bit of adverse yaw,but no handling problems..

Chris RV8 N627CS "Second Chance"
RV3B 11489 in progress.
 
RV3 Drooping Ailerons

This was a report on the RV3 from Oshkosh in 1972.
By flipping this lever over 180deg the ailerons droop 18 deg. The first notch of flaps equals this,creating a high lift wing. More flap can be set in causing drag and steepening the glide path. While in the drooped condition,the Frieze type ailerons still perform their normal function. A little bit of adverse yaw results when the ailerons are dropped--but cause no handling problems, according to VanGrunsven..... The advantages accrue in low stall speeds.... I wonder why this option was never shown on the plans...

Chris Santschi
 
Snowflake said:
If they both drooped the same amount, i'm not sure where you'd get adverse yaw.
Click to expand...

Assume a left turn. The adverse yaw comes from the ( Left) up moving aileron moving towards the in trail position (least amount of drag) and the (Right) down moving one going even further down (producing even more drag). This results in more drag on the right, which yaws the airplane right, even though the turn is to the left.

The RV-3 plans never included this feature because it didn't work. A least it didn't have much effect to be worth the trouble (told to me by Van himself).
The magazine writers liked to write about features, but they didn't always do in-depth research regarding the details.

Think about this...
All of the RV models are a design evolution from the RV-3. If the drooped aileron feature was a good performance trade-off, all of the other models would likely have it.
 
Ah, yes, I see it now. I thought they meant that the adverse yaw would come from just dropping the ailerons in level flight. Dropping them *and* turning would indeed give you adverse yaw.
 
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