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Edge profile for wedge style control surfaces

L

lr172

Well Known Member
My 10's QB control surfaces have the wedge protruding about 1/16" from the skin edges and it is maintained quite uniform in appearance,. This 1/16" gives the effect of coming to thin point at the edge of the part, though it leaves a stair step on each side. I am wondering what the preferred edge style is to stay consistent with the design.

I have the option of doing my best to work the edge to the closest I can get to a point. Or I can file it until it is flat, which would net me about a 3/32"-1/8" thick edge.

Does any one have guidance on the preferred edge profile for aerodynamic performance on these style of control surfaces?

Larry
 
Mine is not an Aircraft educated opinion but in the sailing world our foils are NOT pointed. They are left with a small flat edge. I believe the recommendation for our control surfaces is the same. I filed the wedge off to be flush with the skins to create this flat trailing edge.
 
rvbuilder2002 said:
I don't think this recommendation is in the RV-9, 10 or 14 manuals (all of which have the same type of trailing edge).
Click to expand...

I couldn't find that either or any reference to treating the trailing edge. Section 5 diagrams show the end of the wedge flush with the skins. However, that was not how my parts came from the QB factory. Mine have the wedge about 1/16" proud of the skins.

Scott, do you have a recommendation here? Should I leave it as is and clean it up a bit or should I file it flat or to some type of radius?

Larry
 
Last edited:
lr172 said:
I couldn't find that either or any reference to treating the trailing edge. Section 5 diagrams show the end of the wedge flush with the skins. However, that was not how my parts came from the QB factory. Mine have the wedge about 1/16" proud of the skins.

Scott, do you have a recommendation here? Should I leave it as is and clean it up a bit or should I file it flat or to some type of radius?

Larry
Click to expand...

All of the prototypes have trailing edges that match yours (section 5 is more of a cartooned reference for the purpose of showing info other than a specific trailing edge profile).
That doesn't automatically mean that it is the optimal profile, but it is the standard for the kit.
I would suggest you experiment if you are curious.... unfortunately the only way to determine if it could be optimized would be to fly it as is first, and then see what influence (if any) any changes made.
 
rvbuilder2002 said:
All of the prototypes have trailing edges that match yours (section 5 is more of a cartooned reference for the purpose of showing info other than a specific trailing edge profile).
That doesn't automatically mean that it is the optimal profile, but it is the standard for the kit.
I would suggest you experiment if you are curious.... unfortunately the only way to determine if it could be optimized would be to fly it as is first, and then see what influence (if any) any changes made.
Click to expand...

Thanks. It made sense that they did it that way, as it resembles a true point at the edge. However, they also could have left the edge proud so that you had some meat to file it flat. That is why I asked.

Larry
 
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