flap about flaps

[acwrench]

Working with the flaps on the RV-6. Are the common flap settings strictly 20,30,40 degrees only? As Van sets the down deflection of the Aileron at about 15 deg. ( I believe this is considered most efficient lift for the wing ) has any one looked at a 15 deg notch for the flaps?

Patrick

 

[jsharkey]

You need more flap for landing

You need the 40 deg "barn doors" for drag to help slow down in the pattern, make it easier to stabilize the approach and achieve an easy landing speed.

Before entering the pattern I pull all the power since it's the only way to practically bleed off speed into the white arc. I then deploy half flaps (20 deg +/- by eye) which makes it easier to maintain pattern speed. If everything looks good for landing I deploy full flaps (40 deg to the stop) on base leg. The flaps actually work very well.

For our grass strip (1B8) in calm conditions I use 80kt Downwind, slow down on Base leg to achieve 70kt on Final, over the fence at 65kt and touchdown 60kt+. This gives a nice short, smooth 3 pt landing - most of the time (Get too slow on final though and your seat will drop out from under you pretty rapidly - these aren't C-172s) In windy conditions or on longer paved strips I'll add as many more knots as needed/appropriate.

Jim Sharkey
RV-6 YO-360A1A FP

 

[rvbuilder2002]

Working with the flaps on the RV-6. Are the common flap settings strictly 20,30,40 degrees only? As Van sets the down deflection of the Aileron at about 15 deg. ( I believe this is considered most efficient lift for the wing ) has any one looked at a 15 deg notch for the flaps?

Patrick

The manual flaps degree settings, if built per the plans are ~ zero, 25 and 40 degrees. With electric flaps the setting is infinitely variable.

 

[acwrench]

Scott,

Where did you find the flap degrees? I'm just about to cut the notches in the guide and only found 3 of them on dwg 42. If there is 25 and 40 degrees then the 3rd notch must be for 0 degrees. Right?

Thanks,
Patrick

 

[Mel]

I added a notch to my flap horn when I built it. My flap settings are 13, 26, and 39. 13 is close enough to the optimum of 15 for short field take off and 39 (instead of 40) gives me a small safety margin so that there is no danger of the gap seal popping out if someone leans on the flaps when parked.

BTW, My plans called for 0, 20, and 40.

 

[rvbuilder2002]

Scott,

Where did you find the flap degrees? I'm just about to cut the notches in the guide and only found 3 of them on dwg 42. If there is 25 and 40 degrees then the 3rd notch must be for 0 degrees. Right?

Thanks,
Patrick

I added a notch to my flap horn when I built it. My flap settings are 13, 26, and 39. 13 is close enough to the optimum of 15 for short field take off and 39 (instead of 40) gives me a small safety margin so that there is no danger of the gap seal popping out if someone leans on the flaps when parked.

BTW, My plans called for 0, 20, and 40.

Mel is correct. It is 20 and 40. I was cross pollinating my thoughts because I modified my airplane so that it is 10, 25 and 40.

The third notch is for zero. If there was none, the flaps would slip to the 20 degree notch when there was no air load on them.

 

[RV6AussieNick]

How are you measuring the flap angle, with a digital protractor placed at a given location on the top surface..??

Just curious as I'll probably have to go threw this sort of thing later when i rig the flaps.

Nick..

 

[acwrench]

I used a digital protractor on the top of the wing, the top of the flap should be be the same when in the retracted position.

Patrick