flap brackets and flap alignment with wing

[alpinelakespilot2000]

Has anyone had any issues with the holes their flap brackets (W-925, I think) on the wing not lining up with each other or not being parallel to the wing itself?

Originally when I built the wings, I ran the string through all three flap brackets as directed in the manual. They were then, and still are, perfectly in line with each other. However, what I've found on mine is that the holes in the brackets are not the same distance from the wing itself. The hole in the middle bracket is 1/32 farther from the top wing skin than the hole in the inboard bracket and the hole in the outboard bracket is 1/32 farther away still. The net result is that the trailing edge of the flap is about 1/16" closer to the wing at the inboard position than it is at the outboard. I have no idea how this could be, since most of those holes in the flap brackets were punched by the factory as were the holes in the ribs to which they attach.

I don't know whether this 1/16" matters, and the flap does seem to swing through it's full motion very smoothly, but it seems really strange that the holes in the brackets would not be lined up with the wing. Also, it prevents the flap from aligning with the aileron as well as it might otherwise. This is actually more cosmetically apparent because it allows the outboard corner of the flap to hang down about 3/16" lower than the aileron when the aileron is at its neutral position. (This is especially frustrating after all the effort I went to to get perfectly straight trailing edges on the flaps and ailerons.)

Anybody else been bothered by the same issue? Thanks.

 

[N674P]

Steve - did you get any response to this? It wont be long before I attach these brackets, so this is good to know...

 

[alpinelakespilot2000]

Hi Johnny-

No, I never have gotten an answer, but how I worded the question wasn't exactly clear either.

I don't think the problem lies in what I discovered re: the alignment of the hinge brackets, but rather that one of my flaps has about 3/16" of twist in it that was very hard to find, at first. (Out of 7 control surfaces, it is the only one that has any signficant twist, so I was a little quick to jump the gun and look for problems in other places.) Unfortunately, it is what is causing most of the problem in my flap and ailerons not aligning very well. My flap does move through it's full motion very smoothly, and the three bolts fit pretty well in each bracket, so that's good.

If you are at this stage, I would just try to do the best you can at making sure the hinges are aligned before you rivet them--though since the ribs and brackets are predrilled, I'm not sure there's much you could do to realign it--and then do the best you can to prevent any twist in your flap... which is really tough on an 8-ft flap! Ken Scott from Van's said he didn't think 3/16" over 8 feet was much, but I'm still wondering if I will have to live with that one flap being 3/16" low where it meets the aileron. It really is kind of a bummer, given how hard I worked at keeping everything weighted down and flat but, aside from the aesthetics, Ken said he didn't think it would be a problem and that I'd just have to wait till flight testing to know. If it is a problem, and leads to any significant drag or wing heavy problems, I guess I'll build another flap.

Not sure this helps you much, but I'm happy to let you know how it worked out for me. I'd definitely be interested in hearing from others who have had flap alignment issues and whether or not it proved to be a significant issue for them once flying

Good luck with yours.

 

[jlfernan]

I'm building a 9A QB and had a similar problem. In my case it seems the center bracket on the flap itself is not aligned it took alot of effort to put in the outboard end bolt. I spoke with Scott R. this morning and he is going to run through the engineering dept and get back to me. Nothing yet, but I'll keep you informed.

 

[IowaRV9Dreamer]

In my case it seems the center bracket on the flap itself is not aligned it took alot of effort to put in the outboard end bolt. I spoke with Scott R. this morning and he is going to run through the engineering dept and get back to me. Nothing yet, but I'll keep you informed.

Hi Jorge - did you ever hear back? I have a similar problem. If you put in an end bolt and then the center bolt, it is really hard / impossible to put in the other end bolt. But if you change the sequence and put in the end bolts, it doesn't look like the center hole is far out of line. I am thinking of slightly enlarging (actually dragging) the holes in the center flap hinge brackets. I don't think I'd need more than 1/32.

I'd love to know what Vans told you to do.


Thanks,

dave

 

[jlfernan]

Sorry I never posted a reply. Scott ran it thru engineering and they were of the opinion that that amount of force placed on the bolts while rotating, that is, as the flaps extend and retract, is small compared to the force on them when the flaps are fully extended. He went on to say that these bolts have been tested and they will be able to withstand this force. My problem was that I bought QB wings and felt that since I paid for something that should have been built right, I refused to compromise. My concern was that since I had to force the flap into position, that the flap would br twisting throughout it's travel. I would worry that this twisting, even though minor, would cause stress issues in the future. After a short conversation, Scott agreed to send me a new flap. When it arrived I mounted it and it worked perfectly. Like I said before, while the slight misalignment may have never become a problem, I did not want to compromise.