S

skidmk

Well Known Member
Hi,, this isn't quite clear when it comes to the qb wings. I've pretty much finished the right wing and was wondering if I should drill the flap hinge and rivet it to the brace/skin? any reason not to? any weirdness that I should look out for?

thanks

Mike
 
I "installed" them on the wings very early in my build, at the same time I mounted the ailerons. This was a convenient way to store the flaps (on the wings, in the racks) while I was building the rest of the plane. Of course, they will come off when you start mating the wings, and then you will have to do the cut and fit on the root end, but I had no problems doing the hinges long before.

Paul
 
Mike:

Now is a good time to install the flaps.

One "gotcha" to look out for is the trailing edge alignment between the flap and aileron. When I installed my flaps last year, the trailing edge of the flaps were about 3/16" forward of the trailing edge of the aileron. I know of a few other QB builders that ran into the same issue.

Vans doesn't see it as a problem. They just told me to put the flaps down when I parked and I would never notice it. I opted to fix it.

The fix is to replace half of the -3 piano hinge with a -4. This will give you the room to adjust the flap position without blowing the edge distance on the rivet line.

-Mike Draper
RV-8 Finish
 
ah ha,,,, this is exactly why I was looking for guidance,,, the aileron is sitting back of the flap....

Mike, did you order the new hinge from Van's or another source.

M
 
Flap hinge

Mike

I can't recaill, I either ordered the part from Vans or Aircraft Spruce.

You just need to order 1 hinge. 1/2 will be used for the right flap, the other 1/2 will be used for the left flap. Just check the size of your current hinge and order the next size (width) up.

-Mike Draper
 
Might I suggest one is careful of substituting a larger (wider) hinge without Van's say-so etc. Edge distance might be OK, but is the bigger hinge stressed to take the bending moment of the flaps at the limiting speed? Or if you fit the larger hinge, are you going to reduce the maximum Flap Extension speed? And by how much? And/or are you going to increase the Rivet size?

Just a thought... I'd rather put structural strength / the designer's ideas ahead of cosmetics...
 
thanks

all good points,,,, I dove in head first today and drilled it all up. The plans calls out for 1/8 inch distance from edge of the skin to the "hinge edge"(cut out where hinges fit together) ... I measured it drilled one hole near the end.... I have 6/16ths (and 7/16's ) as an edge distance... fro riveting that was good... do I really need to CS the hinge? or should I dimple it?

now the TE's are exactly 1/8th difference between aileron (longer of 2) and the flap... I can live with that,,,, anyone notices and comments... no rides for them ;) and when I meet you fellas at Osh, or Loe in a couple of years... no measuring tapes allowed near my plane. :p

thanks guys....

M
 
do I really need to CS the hinge? or should I dimple it?
Click to expand...
We C/S it, as per plans.... I think somewhere it says that trying to dimple the hinge = end of hinge, at least as a straight hinge!
 
Preferably prior to flight...:)

As someone else said the flap needs to align with the aileron and fit to the fuse..i fitted mine when i test fitted the wings to the fuse.

Frank
 
Flap/fuselage alignment

frankh said:
As someone else said the flap needs to align with the aileron and fit to the fuse..i fitted mine when i test fitted the wings to the fuse./QUOTE]

I was wondering that. Since it will be a few months before I get my fuselage kit, I was wondering about fitting the flaps and ailerons. The reason I pause is that I was under the belief that the flaps align to the fuse, the ailerons to the flaps, and then the wing tips to the ailerons; to make sure everything lines up. However, the instructions talk about fitting the ailerons once they are built. Anyone care to comment?
Click to expand...
 
Everything aligns with everything else!

Actually the ailerons align with the wing itself...I.e the tooling holes in the end ribs line up with the tip of the aileron at neutral position...clamp a long angle thru the holes and align the aileron tip with the ege of the angle to get the zero point.

The flap then aligns with the aileron, and the tip to the aileron....mine were miles off incidently.

I found I had to role the inner edge of the lower flap skin up to meet the fuse in the fully retracted position. You will also have trim the flap upper skin to match the curve of the fuse side as well.


In short, you can hange the flap and hinge on the wing but you will have to do it again when you hang the wing on the fuse...I would do it all at the same time.

Good luck

Frank
 
If I had to do it over again, I'd not attach the flaps until the wings were on the fuse. I mounted mine first and later found out that they are about .125 too far inboard and rub the fuse side. YMMV
 
Dimp the Hinge,,,, Not!!

If you dimple the hinge it will strech and not fit. Ask me how I know.
 
Countersink the flap hinge

Maybe I just got lucky but I installed the ailerons, adjusted the flap for the 1/4" gap between and used one size larger flap hinge as per Vans FAQ section for more acceptable rivet edge distance. Ref http://www.vansaircraft.com/pdf/Hinge_id.pdf (last paragraph) about swapping hinge halfs. Final alignment was a near perfect trailing edge line from aileron to flap and now that the wings are installed, just about .070" needed to trim off the upper flap skin to get Van's recommended 1/16" gap between flap & fuselage skin. Oh and YES, do not try to dimple the flap hinge. This needs to be countersunk or it will distort beyond use. Everything up to the hinge will be dimpled except for the hinge itself.

BTW the 1/16 gap (minimum) was by recommendation from Van's builder support. I never could find this dimension on my plans!
 
Flap Attachment

I am just finishing up the flaps this weekend and was scratching my head about how they attach to the wings. Either the plans are a little confusing or I am easily confused (or both). On the flap side, the hinge is left intact and you countersink the spar. If I read this correctly, on the wing side you dimple the skin, dimple the flap brace and countersink the hinge. Is that right?

Also, where the flap brace is connected to the rear spar of the wing, do both get dimpled? It sort of looks like they want a flush rivet to avoid scraping the flap. I was, once again, having difficulty figuring out what the plans said.

On the flap side of the hinge, I took Dan Checkaway's advice and placed the hinge as far forward as I could with adequate rivet hole spacing. I am hoping that this will allow use the of standard hinge and good alignment with the aileron. If this is insufficient width, can I substitute the -4 hinge on only one side without dissassembling the flap?

Thanks
Michael Wynn
RV8 Wings (flaps)
San Ramon, CA
 
mlwynn said:
On the flap side, the hinge is left intact and you countersink the spar. If I read this correctly, on the wing side you dimple the skin, dimple the flap brace and countersink the hinge. Is that right?

Also, where the flap brace is connected to the rear spar of the wing, do both get dimpled? It sort of looks like they want a flush rivet to avoid scraping the flap. I was, once again, having difficulty figuring out what the plans said.

On the flap side of the hinge, I took Dan Checkaway's advice and placed the hinge as far forward as I could with adequate rivet hole spacing. I am hoping that this will allow use the of standard hinge and good alignment with the aileron. If this is insufficient width, can I substitute the -4 hinge on only one side without dissassembling the flap?

Thanks
Michael Wynn
RV8 Wings (flaps)
San Ramon, CA
Click to expand...

Michael,

I'm not sure, but I believe that on the RV7 the flap hinge mounts between the skin and the flap brace instead of on top of the brace like it is on our RV8s. This is why they have to countersink the hinge. I plan on countersinking my flap brace (sure glad I didn't rivet the bottom skin yet) for the skin dimples and leaving the hinge whole. I could be wrong about all of this but if you look at RV7 builders sites, the hinge location in between the layers, not on the top of the stackup like it shows on the RV8 plans.

On your second question, there's a disagreement on the plans. If you look at the rivet callout on detail C of the rear spar, there are no flush rivets on the flap brace on the inboard end. If you look at the end view of the flap drawing it does call out flush rivets for the flap brace to spar joint at the stepped inboard end. I'm hoping to mount my flaps this weekend too. If it looks like it's not a problem I'll leave the universal head rivets there. If not, I'll drill them and install flush rivets.

As for question 3 you shouldn't have to rebuild the flaps. Here's the skinny on hinges, straight from Van's. http://www.vansaircraft.com/pdf/Hinge_id.pdf

Cheers,
Guy
 
You must log in or register to reply here.