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Wing Hand Holds covered?

hevansrv7a

Well Known Member
Has anyone taped up the holes in the wings to see if airspeed can be improved or other aerodynamic improvements?
 
My 12 is flying. In that context I don't understand your reply. I am not asking for other changes to make, only if other benefits would be experienced from covering the holes.

Sorry, I was being glib.

I don't *think* covering the hand holds will provide any measurable change in TAS, but if you are game, some aluminum HVAC tape applied parallel to the slip stream would be a sufficient test case to prove/disprove the theory.

(https://www.uline.com/Product/Detai...xD-JYfKT4xzSoF2Rzt0aAh1IEALw_wcB&gclsrc=aw.ds)
 
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I made aluminum handhold covers years ago for my RV12. Each pair are held together by a single flat head screw. They are flush with the top and bottom surfaces and look clean. Knowing that there is bound to be a little extra drag created by those openings was my excuse for creating and installing them. Plus, I like a challenge! I have no empirical data they are of any benefit:)
 
I met a guy at SnF who covered his handles and said he saw no change.
 

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I just covered only my right wing handle hole with packing tape and went out for a flight. I thought if there was a benefit I would be able to notice a yaw. Result, nothing noticeable in the flight of the airplane.
 
Is Air Moving Thru There? Stall Behavior?

I’ve helped my buddy with his RV-12, getting wings on and off and wondered about those holes, too. For openers, they sure are handy. But yeah, I’d wondered about taping them. I was pretty sure the difference in cruise and top speeds would be too small to measure but thought it might be interesting to put tufts around the holes to see how much flow there is thru them. Also thought there might be a difference might (might!) be in stall behavior.
 
Interesting

Not sure that the result can be considered valid though…..

I probably can’t emphasis enough how challenging it is to detect even a couple of its speed increase.

In this instance, if the .5 it is valid, it could be just a result of the amount of fuel you had burned between the first and second test.
 
When I tested it I covered one and left the other open. I felt if there was a significant drag increase the plane would have yawed into the uncovered wing. Even though subjective I could not feel a difference or see a yaw on the instruments. If there is not enough drag to create a yaw in my test I doubt it would slow the plane down overall.
 
Thoughts

I don’t think you would see anything improvement. Example just the opposite I have a GoPro mount that covers the wing handle and do not see any improvement or decrease in performance with the cover only or the cover and GoPro.

072514 c.jpg


From an photo from an old RV12 post.
 
Interesting

In this instance, if the .5 it is valid, it could be just a result of the amount of fuel you had burned between the first and second test.

I had taken this into account during the daytime tests. I used the G3X's "Fuel Used" data and I added some weight on top of the fuel tank - so I rolled down the runway with the same exact weight. However, I scrapped the results completely because it was nearly... well, absolutely impossible to draw any conclusions from the daytime data (turbulence, up/downdrafts, etc).

I re-tested at night time.. and you're right.. I didn't compensate for fuel burn during those tests (the ones the results were based on).

I burned 1.18 gal (7.1 lb) from the conclusion of the first night test to the beginning of the second night test. (that's based on Excel doing some math on the Fuel Flow column of the G3X log file)

If yous think 7lbs would have an effect, I'm willing to re-do the test. But, results would have to show something more than ½ knot in order to change the the final conclusions drawn here.
 
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