Section 29 - side skin bending - a good reason to go the quick build route

[RV6-KPTW]

But here we are. I am not a quitter. I made 6 elevator trim tabs till I was happy (less dissatisfied). But I don’t have an unlimited budget and these side skins are expensive. I need help and have exhausted my local supply (in one case, literally).

I know there are build assist centers (which is an option but drive to GA) but is there anyone in south east Florida who thinks this skin bending thing is a trivial activity? I can load up my stuff and drive to you!

I can take additional direction but any thing that sounds like “just follow the plans” will be ignored. Don’t point out my mistakes. I know. I do not need cheerleading, I need experience and expertise.

Ignore the attitude, it is me, not you.

Thanks

 

[Richard Connell]

I found it’s more of a rotation/twist than a “bend”
Try focusing on twisting with the multi grips while not allowing the skin to rise up.
I’m pretty sure I stuck all the clecoes on the outside as well as the ones closest to the multi grips get too close to the bench on the inside of the bend.
It dosent have to be “perfect”. The act of clecoing it all to the fuselage helps a lot as long as you don’t put too much strain on the sharp vertex at the opposite end from the multi grips

 

[wirejock]

That looks like the method except the clekos will interfere. Maybe move them to the outside.
Similar bend on the 7. Very important to have a nice smooth relief at the tightest point. There's probably a hole already. Helps to file it and debur it. My first one cracked.
As mentioned, it's more of a roll than a bend. Kinda like a control surface leading edge roll.

 

[kirkbauer]

Move Clecos to the outside. The angle aluminum will need to touch the wood ultimately. You really need a full (but rounded) 90 degree bend. I found i had to push out to force a curve while I twisted inwards. You have to avoid a crease and keep it rounded and just keep working it again and again.

At some point I put a PVC pipe on the vice grip handle for more leverage.

At the narrow end I used a rubber mallet to almost crease the very end... Hold the shape then hammer to lock it in place.

I'm sure you have checked the wiki but I think I added some tips there too.

 

[RV6-KPTW]

I found it’s more of a rotation/twist than a “bend”
Try focusing on twisting with the multi grips while not allowing the skin to rise up.

Ok. I am back off the ledge…. At least till I finish my coffee and get to the shop.

This thing has been a huge gumption trap and I need it behind me.

Thanks

 

[kirkbauer]

Ok. I am back off the ledge…. At least till I finish my coffee and get to the shop.

This thing has been a huge gumption trap and I need it behind me.

Thanks

Yes I felt the same way. Finishing that section is a huge milestone in my opinion.

 

[RV6-KPTW]

Yes I felt the same way. Finishing that section is a huge milestone in my opinion.

I would be happy (less dissatisfied) just getting these bends done. My impression of this section of the plans is that the instruction quality is starkly different. It is not very logical and there are many disconnects. I have guessed correctly in several instances but my luck will run out.

 

[RV6-KPTW]

I took all of your suggestions:

• Move clecos to outside
• PVC pipe for leverage
• Rotation / twist / more of a roll
• Put more effort into the downward twisting roll than I thought sane initially

And lo, it worked. I did the left skin including setup in about 15 minutes. I agonized over the right skin for a couple of hours across two days. The left looks perfect while the right looks pretty good from my house a couple of miles away but up close merely OK. I am pretty sure I can make it work.

Thanks all!

 

[RV6-KPTW]

Ya know, I read ahead and did not see anywhere that stated “do the LEFT mid side skin bend now”. I followed the right up by bending the left and thought that these would be symmetrical. I just assumed that this particular section was not well written. Tell me it is so.

Thanks.

 

[kirkbauer]

Ya know, I read ahead and did not see anywhere that stated “do the LEFT mid side skin bend now”. I followed the right up by bending the left and thought that these would be symmetrical. I just assumed that this particular section was not well written. Tell me it is so.

Thanks.

Yes, symmetrical, so the other skin should be the same but mirrored. That doesn't seem to be the only thing left out in this section. I noticed on 29-3, Step 3 it says to do both the forward and aft twists on the right longeron, but it doesn't mention the forward twist on the left longeron (the forward twist needs to be done on both left and right).

 

[RV6-KPTW]

Thanks for the confirmation.

This section has been driving me crazy with little stuff like that. Usually, if not immediately stated, you will come upon it in an upcoming section. Not in this section. Another example - where is the material detailed to make the roll construction angles F-1070A and B? Given the kit has a limited amount of material, one would think a specified material (ie aa6-125-3/4x/3/4) would help use the kit contents appropriately. But no…. Move on. Ranting….I don’t need my hand held but should not be forced to guess.

 

[lonkelm]

I found it’s more of a rotation/twist than a “bend”
Try focusing on twisting with the multi grips while not allowing the skin to rise up.
I’m pretty sure I stuck all the clecoes on the outside as well as the ones closest to the multi grips get too close to the bench on the inside of the bend.
It dosent have to be “perfect”. The act of clecoing it all to the fuselage helps a lot as long as you don’t put too much strain on the sharp vertex at the opposite end from the multi grips

Finished this section not too long ago. Well described. I'm a big guy and this step was the most force/effort needed yet. Sweat was broken to get it correct.

 

[Everwild]

Any more tips or photos on this? @Vans how about doing a how-to video on this?

I cracked my passenger side mid skin at the tight radius. It tore at the relief hole. Pilot side went smoothly.

I cracked the pilot side forward skin at the tight radius. It cracked right along the edge of the angle.

Now scared to blow up a third skin. Will be ordering replacements for the cracked skins but these are not cheap

My understanding is the RV14 they are done at the factory? Might be a good idea for Vans to to pre-bend them on the RV10?????

Frustrating.

 

[Richard Connell]

Any more tips or photos on this? @Vans how about doing a how-to video on this?

I cracked my passenger side mid skin at the tight radius. It tore at the relief hole. Pilot side went smoothly.

I cracked the pilot side forward skin at the tight radius. It cracked right along the edge of the angle.

Now scared to blow up a third skin. Will be ordering replacements for the cracked skins but these are not cheap

My understanding is the RV14 they are done at the factory? Might be a good idea for Vans to to pre-bend them on the RV10?????

Frustrating.

The first observation I’d make is that the best way to stop cracks from initiating is to thoroughly debur the skin edges. Particularly the inside corners. And when I say thoroughly, I mean almost polished on those inside radii. That will go a long way towards prevention.

 

[johnbright]

I remember this on my RV-6A. When I pointed out to others the roll in the skin is not perfect they couldn’t tell so don’t be hard on yourself. If you find someone lying on the ground looking at it you’ll know they are a builder!

I believe it’s fundamental to apply close to pure torque to the F107A and B roll construction angles. If one applies force to the construction angles relative to the clamping block the skin becomes a cantilevered beam with max bending moment at its root, the clamping block, where the skin will crease at best and crack at worst.

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Off-topic TLDR:

Fortunately for us (!), the Van’s Air Force builder community is here to fill in the gaps re how to build.
In a former time, before VAF, in the 1990’s, re the RV-6A I am close to finishing, plans were hand-drawn with separate build instructions. The Frank Justice (EAA 105 nearby Van’s) Supplemental Instructions were a lifesaver, all text, no photos, was written, and had to be read, in great detail.
The RV-10 plans and parts, and the RV-14 plans and parts more so, are a great improvement compared to the RV-6 plans and parts. Each successive model gets better in terms of ease of assembly and part quality, 3, 4, 6, 7, 8, 9, 10, 14.
Jig-less assembly with prepunched skins and substructure… dreamy.
Die-cut baffle material (RV-14(A))… sweet… takes guesswork out of fitting them.
Documentation is expensive and at homebuilt production volumes there’s not a lot of units to spread the cost around. At such low production volumes a lot of things are not ideal on the factory floor (our shops), improvements happen slowly and tooling is less than ideal.

 

[glider_rider]

My understanding is the RV14 they are done at the factory? Might be a good idea for Vans to to pre-bend them on the RV10?????

Yep, 14 is way easier to built well than 10. And I'm sure 15 will be easier to built than 14. Natural order of things.
I would say that bending those skins is best done by a two man team. It takes both strength and precision, I wouldn't do it alone.