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RV-4 and RV-6 wing skins the same?

F

FinnFlyer

Well Known Member
I'll be needing right wing outer leading edge and top wing skins to replace crinkled skins from my forced landing ground loop.

I see RV-4 pre-punched skins in Van's store, but that won't work.

So before I start looking for replacement skins, can anyone confirm that the outer skins are the same for RV-4 and RV-6 wings?
 
6 wings that I have reskinned have always been hand drilled to match the original panel.
As for being interchangeable with a 4, I doubt it.
Original paper 6 plans have the dimensions for each panel. I have cut replacement panels from raw sheets of aluminum (4x12 sheets) using a router & straight edge fence. Very good edge quality using this method if you don’t have access to a cutting shear.
 
It might not be necessary for sheet aluminum, but you can get a spiral-blade metal-cutter for a router. I used one on the longerons on my RV-3B and it went smoothly.

I used 1" wide angle to have that width where other builders have complained about low edge distance, while still saving the weight where it wasn't needed, where the stock width was 3/4".

Dave
 
Ralph Inkster said:
6 wings that I have reskinned have always been hand drilled to match the original panel.
As for being interchangeable with a 4, I doubt it.
Original paper 6 plans have the dimensions for each panel. I have cut replacement panels from raw sheets of aluminum (4x12 sheets) using a router & straight edge fence. Very good edge quality using this method if you don’t have access to a cutting shear.
Click to expand...
How about forming the leading edge?
 
FinnFlyer said:
How about forming the leadin
Click to expand...
My method is crude, but I got excellent results doing it this way.
When cutting the LE skin, oversize it so it overlaps the wing top & bottom skins by a couple inches (this will give you an allowance if your bend doesn’t end up exactly where you wanted it) you can trim the excess off later.
Bend the panel over & tape the trailing edges together, note to make sure the corners match.
Place on a solid, smooth surface. Using a 2x4 to apply equal force, press down to create the LE bend till the desired radius of the LE is achieved. Adjust the position of the 2x4 to align the bend to your intended LE marks. Go slow, un-tape the trailing edges & check your bend radius often.
When you are satisfied with your bend radius, place the skin on the wing, lightly secure the LE skin with load straps, position to match the LE bend with the gas tank LE contour. Mark and trim the aft overlapping material.
Good luck!
 
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Ralph Inkster said:
My method is crude, but I got excellent results doing it this way.
When cutting the LE skin, oversize it so it overlaps the wing top & bottom skins by a couple inches (this will give you an allowance if your bend doesn’t end up exactly where you wanted it) you can trim the excess off later.
Bend the panel over & tape the trailing edges together, note to make sure the corners match.
Place on a solid, smooth surface. Using a 2x4 to apply equal force, press down to create the LE bend till the desired radius of the LE is achieved. Adjust the position of the 2x4 to align the bend to your intended LE marks. Go slow, un-tape the trailing edges & check your bend radius often.
When you are satisfied with your bend radius, place the skin on the wing, lightly secure the LE skin with load straps, position to match the LE bend with the gas tank LE contour. Mark and trim the aft overlapping material.
Good luck!
Click to expand...
Thanks Ralph.

I seem to remember a series of sharpie marks on both ends of the skin at the bend(s) on the factory skins. In other words, the possibility that the factory does a series of gradual bends on a brake to form the leading edge. But I guess if you get close enough the ribs will take care of the rest.

Oh, wait. You write "your intended LE marks". How do you make those?
 
I used a bending brake to do a series of LE bends on my first 6, great results. Of course I didn’t remember that on a 6 rebuild project 15 years later… & did the crude method, excellent results too. Maybe just lucky
Either way, I’d suggest the oversize & trim to get the positioning just right
 
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According to my ancient RV-4 and RV-6 manuals, the RV-4 Outboard skins are longer.

RV-4 Outboard L.E. skin 70 13/16" by 39 3/8". Outboard Top 65 1/4" by 28 7/16". Bottom 65 1/4" by 28 5/16".

RV-6 Outboard L.E. skin 55" by 39 3/8". Outboard Top 63" by 28 11/16". Outboard Bottom 63" by 28 7/16".

I had ordered the plans when Van's offered them on CD and now, they sell a thumb drive. But these drawings are not on the old CD's. Go figure.
 
arffguy said:
According to my ancient RV-4 and RV-6 manuals, the RV-4 Outboard skins are longer.

RV-4 Outboard L.E. skin 70 13/16" by 39 3/8". Outboard Top 65 1/4" by 28 7/16". Bottom 65 1/4" by 28 5/16".

RV-6 Outboard L.E. skin 55" by 39 3/8". Outboard Top 63" by 28 11/16". Outboard Bottom 63" by 28 7/16".

I had ordered the plans when Van's offered them on CD and now, they sell a thumb drive. But these drawings are not on the old CD's. Go figure.
Click to expand...
Thank you so much Mike!
I have two sets of RV-4 manuals and drawings but couldn't find the dimensions on neither.

But that narrows down the possibility to only finding someone relatively nearby that might have a a spare RV-4 LE (and/or) top outer skin laying around they might want to sell.

If that fails I think I'll order a 4x12' 0.025 sheet from Aircraft Spruce, GA. Shipping drops to a reasonable $56 if I allow them to roll it up for shipping. Any big downside to that?

I'll then have to study up on sheet metal bending -- I'm far, far from being a sheet metal wizard.
 
FinnFlyer said:
I'll be needing right wing outer leading edge and top wing skins to replace crinkled skins from my forced landing ground loop.

I see RV-4 pre-punched skins in Van's store, but that won't work.

So before I start looking for replacement skins, can anyone confirm that the outer skins are the same for RV-4 and RV-6 wings?
Click to expand...
Just ask VANs to send you a skin that isn’t prepunched.
 
FinnFlyer said:
I'll be needing right wing outer leading edge and top wing skins to replace crinkled skins from my forced landing ground loop.

I see RV-4 pre-punched skins in Van's store, but that won't work.

So before I start looking for replacement skins, can anyone confirm that the outer skins are the same for RV-4 and RV-6 wings?
Click to expand...
Finn,
4 & 6 wing skins are not the same, due to differing fuselage widths. Both have 23 foot wing spans. If you decide to order from Vans, you can request skins without the pre-punching. It will delay the time to ship.

Save yourself the cost of shipping. Check to see if there is a Future Metals location near you. You can buy the 2024-T3 from them and either pick it up or have it shipped.

https://futuremetals.com/

Years ago, I decided I wanted 1 piece main wing skins [ala the Bakerfield Bunch]. I bought two 5' X 12' sheets from them. I requested to have PVC plastic applied to minimize scratches [no extra charge]. Since their SE Florida location is about 20 miles from me, they even shipped it via truck for free. I was able to make 4 main skins with lots of left over material, which I put to good use.

Regarding shaping the leading edge skin, perhaps the Kitplanes articles linked below will help.

Just a Little Squeeze

Get Bent
 
Ralph Inkster said:
My method is crude, but I got excellent results doing it this way.
When cutting the LE skin, oversize it so it overlaps the wing top & bottom skins by a couple inches (this will give you an allowance if your bend doesn’t end up exactly where you wanted it) you can trim the excess off later.
Bend the panel over & tape the trailing edges together, note to make sure the corners match.
Place on a solid, smooth surface. Using a 2x4 to apply equal force, press down to create the LE bend till the desired radius of the LE is achieved. Adjust the position of the 2x4 to align the bend to your intended LE marks. Go slow, un-tape the trailing edges & check your bend radius often.
When you are satisfied with your bend radius, place the skin on the wing, lightly secure the LE skin with load straps, position to match the LE bend with the gas tank LE contour. Mark and trim the aft overlapping material.
Good luck!
Click to expand...
I used my garage door, towels on the floor use the door with hand pressure to incrementally work the bend using a nose rib as a template. Not hard, go slowly and check bend frequently.
 
The RV-6 is a wider fuselage so RV-4 wing is different, I built both way back in the late 80's early 90's. I don't recall if the outer wing sinks were the same.

Both these kits as you obviously know are not pre punched, drilled in situ (in place) by hand laid-out patterns (per drawing). No two planes are exactly alike.

If I were you, buy RAW material net size. The old drawings use to have dimensions. New ones do not, and not really to a scale. It is just a flat sheet of 2024-T3 (0.032t I recall). Be ready for sticker shock and shipping is also an (expensive) thing. If you can pick it up that would save money.

Drill out rivets and use the old skin for template. This is a big job but doable one rivet at a time. Access to rivets will be difficult for bucking, but if you use the "L" pattern and roll it on, two people, can do it with few pull rivets. Good luck.

As advised above call van's. They will sell you a blank sheet I am pretty sure.
 
Using the flat skin as template (even if crinkled) should be easy enough. It's an entirely different matter with the curved leading edge skin. I'm anticipating having to back-drill that using an angle drill. In any case I probably won't have the patience to get as perfect fit as when I originally built it -- can hardly get a hair in between the skin seams.

Mike was kind enough to provide me with the actual dimensions in post #9. One reason for the shorter LE skins on the RV-6 is its larger tanks. The other is the wider fuselage in the RV-6.
 
FinnFlyer said:
Thank you so much Mike!
I have two sets of RV-4 manuals and drawings but couldn't find the dimensions on neither.

But that narrows down the possibility to only finding someone relatively nearby that might have a a spare RV-4 LE (and/or) top outer skin laying around they might want to sell.

If that fails I think I'll order a 4x12' 0.025 sheet from Aircraft Spruce, GA. Shipping drops to a reasonable $56 if I allow them to roll it up for shipping. Any big downside to that?

I'll then have to study up on sheet metal bending -- I'm far, far from being a sheet metal wizard.
Click to expand...
just remember; folding and bending should be done perpendicular to the grain.
 
FlyingDutchman257 said:
just remember; folding and bending should be done perpendicular to the grain.
Click to expand...
Because the standard sizes from factory appear to be 4' wide x X' long (in this case 4' x 12') I don't think there is any choice when rolling it up. (I assume grain runs along the 4' width?)

And for bending, because the wing skins are more than 4' wide, I think the leading edge bend will be along the grain, not perpendicular? Probably not a factor because of the very, very gradual bend compared to sheet thickness.
 
FinnFlyer said:
Because the standard sizes from factory appear to be 4' wide x X' long (in this case 4' x 12') I don't think there is any choice when rolling it up. (I assume grain runs along the 4' width?)

And for bending, because the wing skins are more than 4' wide, I think the leading edge bend will be along the grain, not perpendicular? Probably not a factor because of the very, very gradual bend compared to sheet thickness.
Click to expand...
5' is also available and the grain runs along the lenght not the width. Bending and rolling are not the same. Have a look, Chapter 4, "Metal structure, welding and brazing", AC43-13-1B. You can download it from the FAA website, if you have not got it in print.
 
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