Aileron Bending Dilemma

bobmarkert · #1 04-01-2013, 04:57 AM

So here is my dilemma. I can’t figure out how comply with the directions for the final bend of the aileron trailing edge. According to the plans, I need to bend the aileron so it lays flat against the spar while still preserving the specified trailing edge bend radius. As you can see I haven’t gotten there and can’t seem to serve two masters. I’ve used a 3/16th” dowel in the trailing edge to maintain the radius and squeeze the aileron in a wooden brake until the stiffeners touch at the front. Anymore/harder compression will dent the skins with the stiffeners. I then get spring –back so I end up with a 1 ½ gap at the spar. I also tried without the dowel but started to get a too tight radius. The close-up picture of the trailing edge is deceiving. The radius is the correct size according to the plans but it looks too big in the picture. My gut say cleco it down and rivet it. My directions say make it lay flat. You would think at this stage of the build I would have these processes figured out already…..sigh…..
Any suggestions are appreciated

tkatc · #2 04-01-2013, 06:26 AM

Can't be sure from the picture but you didn't put the stiffeners on backwards did you?

Probably not but thought I'd mention it anyway.

bobmarkert · #3 04-01-2013, 06:48 AM

Stiffeners in correctly

ColoRv · #4 04-01-2013, 07:12 AM

When you cleko it down, what does the trailing edge look like? If its bulging up prior to the bend, I would give it a bit more of a squeeze until there isn't any more tension holding that last inch or so up.

Please don't take my word for it though...I'm a nobody. If it were me and I were building to the level of perfection you are, I think I would calls Vans for an opinion.

bird · #5 04-01-2013, 08:15 AM

Hmm is there an angle cut on the aft part of the stiffeners,like on the front?

Bird

RV7Ron · #6 04-01-2013, 10:36 AM

Sorry, missed your call buddy. My thoughts, for what they are worth.

First, I didnt even use a dowel...with the rudimentary (i.e., not very effective) brake that we use, I dont think you could violate the bend radius...mine seemed to come out fine without a dowel, but proceed at your own risk.

Second, I dont think anyone gets them bent all the way flush with the ribs with the brake alone...your pics look pretty normal actually...remember you want to sneak up on it, you can add more bend but cant take it out so be careful. You can get them close with the brake but not all the way. You need to coax them...talk nicely to them to get them to cooperate. I did use this technique from Paul Dye to get them nice and straight after the fact...you dont want a "bulge" when you lay a straight edge on them.

Good luck and we can talk more if you want.

bobmarkert · #7 04-01-2013, 10:58 AM

The stiffeners were cut and prepared using the notches that come on the stiffeners from Vans.

longranger · #8 04-01-2013, 12:41 PM

If you build the brake to use the narrow edge of the lumber for the bending, you can get more leverage and actually bend the skin so the forward edge acually lays down on on the spar. Check my build log to see what I'm talking about. I didn't use a dowel, but I did sneak up on the bend, taking 5 or 6 iterations to get it where I wanted it.

Here's an end view of what it looks like when it's right:

bobmarkert · #9 04-03-2013, 03:48 AM

Here is the resolution for my ailerons. I sent Vans a link to my posts here on VAF and asked for advice and got this response:

? After looking at your pictures I think you could get away with riveting as is but if you cleco this up and the trailing edge bulges a little you can press it with light pressure without the dowel until this goes away?

I decided to eliminate the dowel and just use the press. Whaaaallaaaa!!!. I think the trailing edge radius is a smidgen under the prescribed radius but I refuse to start stressing about that. It is also slightly concave at one end but when I insert the end rib it is perfectly straight?? build on?.

Flyin'Bryan · #10 04-03-2013, 01:10 PM

Quote:

Originally Posted by bobmarkert

Here is the resolution for my ailerons. I sent Vans a link to my posts here on VAF and asked for advice and got this response:

? After looking at your pictures I think you could get away with riveting as is but if you cleco this up and the trailing edge bulges a little you can press it with light pressure without the dowel until this goes away?

I decided to eliminate the dowel and just use the press. Whaaaallaaaa!!!. I think the trailing edge radius is a smidgen under the prescribed radius but I refuse to start stressing about that. It is also slightly concave at one end but when I insert the end rib it is perfectly straight?? build on?.

Bob - looks like the "without the dowel" method that you and Miles (and perhaps everyone else) has employed seems to do the trick. While I am not quite up to that part of the build yet, the only reason that 3/16 of an inch comes to mind is because that is also the size of the tooling holes in the wing tip rib that you are supposed to use to align the aileron at the true neutral position.

Other than that, the process you used reminds me alot of what you and I did to bend my rudder, as well as the elevators that I did on my own. Looks pretty darn good to me. I like Vans suggestion to cleco it down and then only apply enough additional bend to remove the bulge - I will apply that same method to my ailerons when the time comes.

Don't hesitate to swing by if you need some rivets!