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stall characteristics

amekler

Well Known Member
Patron
Doing flight testing in my ELSA RV-12 and have noticed a pretty abrupt drop of the right wing in a stall. I have a RV-10 that just shakes the tail and mushes in the stall.
Is this normal for the RV-12?
ps ball is centered and right wing seems a bit heavy

Alan
N603NH
Rv-12 3 hrs so far
 
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Adjusting the heavy right wing would be a good place to start. Mine just mushes along in a stall with the ball centered.
 
I had the exact same problem. It was like riding a bull as it dropped to right. In fact sometimes I'd even find coolant that had come out of the vent tube because the negative G during the stall would push it up and out of the overflow bottle. It was a really aggressive stall break to the right.

I had the wing gap seal taped with glider tape as cleanly and as tightly as I could.

Once I finally precisely installed the rubber gap seal provided by Vans, the stall break became a very tame mushing of controls with maaaaybe the slightest break to the right.

I wouldnt start bending wing metal to fix a heavy wing until you've got that final gap seal installed. I'm glad that I decided to wait and see what the "final" stall characteristics were.
 
Yes, I would fix heavy wing first. Then I would check for heavy wing with one notch of flap, and then again with full-flap. In each case, I would trim hands-off for 55 KIAS. My 12 flies level in roll axis at cruise and with flaps extended. Stall is a non-event… both clean and with flaps.

As side note... I have flown plane with and w/o wing root seals and it flies same either way including stalls clean and with flaps....
 
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I had the exact same problem. It was like riding a bull as it dropped to right. In fact sometimes I'd even find coolant that had come out of the vent tube because the negative G during the stall would push it up and out of the overflow bottle. It was a really aggressive stall break to the right.

I had the wing gap seal taped with glider tape as cleanly and as tightly as I could.

Once I finally precisely installed the rubber gap seal provided by Vans, the stall break became a very tame mushing of controls with maaaaybe the slightest break to the right.

I wouldnt start bending wing metal to fix a heavy wing until you've got that final gap seal installed. I'm glad that I decided to wait and see what the "final" stall characteristics were.


Very interesting.
I also have Glider tape. I have a rudder trim tab that I moved about 1/8 inch to center the ball. I was about to check the rigging but maybe first I should install the seals as there is a 2 year wait at the paint shop
Alan
N603NH
flight test 1-5 completed
 
Once I finally precisely installed the rubber gap seal provided by Vans, the stall break became a very tame mushing of controls with maaaaybe the slightest break to the right.

I currently have no seals installed and I get a sharp break to the right too. Good to hear that the seals may correct that. (I opted not to install them until it gets painted later this year)
 
My RV-12 exhibited the same behavior during power on stalls. It flew straight, regardless of flap position in slow speed flight.

I never really figured out or mastered that right wing drop at power on stall, as I had a lot of right rudder kicked in just to keep the plane on course. My instructor had no problem with it, nor did my fellow RV-12 friend who also flew my plane. Nose just dropped normally, for them, wings level. More experience, more coordination with hands and feet?

There is a normal P effect from the rotation of the prop providing the left wing with more lift than the right wing, therefore the right wing will stall first, it's pretty normal. Some plane wing designs mess up the laminar flow on the leading edge of the left wing such that the plane exhibits equal lift from both wings near stall speed. I don't know if the RV-12 has this engineered into their wing design or not.

I chalked it up as a lack of experience / coordination on my part, because I went and flew a PA28 150, and it's behavior during a power on stall was down right docile, child's play.

Maybe try it a few more times and see if you can get the coordination? My wings buffeted at the root for quite some time before my plane would actually stall and the right wing and nose would drop very quickly.

Or let someone else with an RV-12 fly it to confirm?

i did have proper seals installed.
 
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Heavy Wing

Over the years there have been many posts regarding heavy wing (usually as I recall the right wing). I suggest your read Vans PAP regarding "Lateral (roll) trim". If you have that kind of issue, the procedure outlined will fix the problem. It did for me. Some have reported successfully using a trim tab on one wing.
 
I had the exact same problem. It was like riding a bull as it dropped to right. In fact sometimes I'd even find coolant that had come out of the vent tube because the negative G during the stall would push it up and out of the overflow bottle. It was a really aggressive stall break to the right.

I had the wing gap seal taped with glider tape as cleanly and as tightly as I could.

Once I finally precisely installed the rubber gap seal provided by Vans, the stall break became a very tame mushing of controls with maaaaybe the slightest break to the right.

I wouldnt start bending wing metal to fix a heavy wing until you've got that final gap seal installed. I'm glad that I decided to wait and see what the "final" stall characteristics were.

I can't think of a reason there would be a difference between glider tape and the rubber seals.

Jerre
 
Completely agree. But the only thing that's changed is my root seals. And my stalls are mild and comfortable now as compared to the right wing dive.
 
Some have reported successfully using a trim tab on one wing.

I'd be reluctant to add a trim tab. A fixed tab only works correctly at one speed... usually bent correctly for cruise. Rudder tab is that way... works well in cruise, but need to hold right rudder in climb and left rudder in glide.
 
All of our company built RV-12's and 12iS's have mild stall characteristics with no tendency for abrupt wing drop, etc., if in coordinated flight.
In fact, at C.G's more in the fwd. part of the allowable range, it is difficult to get a stall break flaps up (tends to just mush with a high sink rate).
 
All of our company built RV-12's and 12iS's have mild stall characteristics with no tendency for abrupt wing drop, etc., if in coordinated flight.
In fact, at C.G's more in the fwd. part of the allowable range, it is difficult to get a stall break flaps up (tends to just mush with a high sink rate).

should I remove the sail tape and install seals(2 year wait at the paint shop)? or should I troubleshoot elsewhere?
Alan
 
should I remove the sail tape and install seals(2 year wait at the paint shop)? or should I troubleshoot elsewhere?
Alan

If taped properly, I would think that performance should be the same as with the factory seal installed, but without being able to personally inspect the tape job, I can't really comment on whether it will make a difference on your airplane.

If you post a few photos we could take a look at it.
 
Stall Test

I just finished my first stall test and I had to hold it in the stall to get it to drop a wing

https://www.youtube.com/watch?v=RRfojL1Pgf8

Doing flight testing in my ELSA RV-12 and have noticed a pretty abrupt drop of the right wing in a stall. I have a RV-10 that just shakes the tail and mushes in the stall.
Is this normal for the RV-12?
ps ball is centered and right wing seems a bit heavy

Alan
N603NH
Rv-12 3 hrs so far
 
If taped properly, I would think that performance should be the same as with the factory seal installed, but without being able to personally inspect the tape job, I can't really comment on whether it will make a difference on your airplane.

If you post a few photos we could take a look at it.
here are photos
 

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I'm retaping my wing roots and try flying again. I noticed when my plane is leveled on the ground the skid/slip ball is slightly to the right. The Dynon Adahrs
mount to the skin is pretty flimsy. By pushing on the skin near the rivets it aligns.
Alan
N603NH
RV-12
7 hrs
 
There was a design change incorporated many years ago that added a lateral skin stiffener beside the ADHRS bracket that you may not have.
 
Yes, I would fix heavy wing first. Then I would check for heavy wing with one notch of flap, and then again with full-flap. In each case, I would trim hands-off for 55 KIAS. My 12 flies level in roll axis at cruise and with flaps extended. Stall is a non-event… both clean and with flaps.

As side note... I have flown plane with and w/o wing root seals and it flies same either way including stalls clean and with flaps....

So far I have found the right flaperon (heavy wing) to be slightly lower than the left and turned the control end half a turn in bringing both flaperons identical to .192 inches droop but there was no change in the right roll tendency. Ball is centered perfectly with feet off the pedals.
However if I take the flap handle out of the no flaps detent towards the floor floor the plane flies straight with no roll tendency.

Alan
N603NH
RV-12
12 hrs
 
Reto fit AOA kit

I know there is a classified section but since this is topic related I have an AOA kit I considered installation during my last annual. It’s still in the padded envelope and I will ship it to the first $30 within the lower 48. PM me if you are interested. Thanks
 
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