rear spar reinforcement plate dimensions

[ditch]

I fear I may be in for a world of hurt right now. Just read a post with a link to another topic about the reinforcement plate on the rear spar. Talked about the 5/8 rule when mating the wings to fuselage. Here's my problem. When I shaped the plates, all I had was the diagram on the plans with the wing and that was at 1/2 scale. It said to look at plan #38 to get dimensions. Looks like vans sent me the plans for the rv-9 for the binder. That did me no good. Didn't think anything of it because I figured I'd just use the large ones with the kit when they arrived. I know see how critical the shape needs to be to keep the 5/8 rule when drilling the holes to mate up. I used the drawing on the large plans at 1/2 scale and doubled the measurements. Here's my dillema, my left wing is done and I get an absolute measurement of 1.5 inches of plate out past the inboard rib. Can anyone out there that measured their plate correctly tell me if that is enough sticking out so I won't have a issue when mating up the fuse? Also, I'm not sure how you would measure to see if I'd have enough clearance on the bottom to keep the 5/8 rule also. I know that my right wing is wrong. Almost 1/8 inch short on the plate but that's not a big deal now since the rear spar is still seperate. I could wait until tomorrow to call vans to get dimentions but I didn't get any sleep last night and don't want another night like that
Is there some wiggle room up and down when mating the fuse? If there is I may be ok on the left wing (hopefully) if I have enough sticking out in the first place. PLEASE HELP

 

[Jeff Vaughan]

Rear Spar dimension

Hello Greg,

I measured mine at 1-18/32. Now I have not mated my wings yet and I did the trimming 2 years ago. Not sure this helps.

 

[ditch]

Well, thats close. If someone can chime in on the size of area you have to actually drill the hole, that would help too. I guess what I would like to know, is there enough space on the spar and fuselage plates to move the spot where you drill the hole around to make sure you get the 5/8. Example, if the plate is to small, just move the hole further inside to get the distance or is the plate coming out of the fuse to small to move the hole location around? How much "wiggle" room is there for the hole placement?

 

[TJoyner]

I've got about 1-18/32" as well if measured at the lower portion of the plate outboard of the rib flange. The measurements on the plans left a lot up to the imagination here. Considering how critical they are I wish they would improve them, I've fussed over this quite a bit....

 

[LettersFromFlyoverCountry]

Greg: I posted a response on the OLD thread (man, you're a moving target!)

Part of the situation here is you have to remove (most of) the forward sweep in the wings when you're mating. So this moves where exactly that reinforcing plate fits within the fork.

It's a little difficult to pinpoint exactly where to drill because the edge of the plate is invisible once you mate the wings. Chances are you'll lift the rear of the wings slightly to get the proper angle. And as you can see (in the picture in the other thread), the plate edge angles a bit.

One mistake I THINK I also made was that I concentrated a little too much on the edge distance on the fuselage fork, and I might've cheated inboard just a bit. Well, of course, when you do that, you're actually moving the hole in the plate (that fits like a sandwich in the fork) TOWARD the edge. Not too good.

No, there isn't a lot of room to play with in locating the hole. I'd guess the "box" is about a 1/2" wide. But, like I said, my mistake was really more of where I located the hole than the 32nds I lost in trimming the plate. I moved the hole all the way to the edge of that 1/2" box and that decision, along with the improper trimming of the reinforcement plate, conspired to do me in once I made the third critical mistake -- not drilling a straight hole. If any one of those things doesn't occur, I'm fine.

My advice? Your odds of being as stupid as me are probably astronomical.

If you read up on what to do when mating wings, you'll see LOTS and lots of warnings to take your time, go have a sandwich just before drilling, etc. It's really good advice. Also, have another RV builder with you when you're doing this. Another mistake I made.

Keep in mind, also, that if you find an edge distance problem here before drilling, you always have the option of adjusting the forward/rear sweep a little bit (and it would be just a little bit) to give you a few more 32nds of edge distance. We obsess too much over the forward sweep anyway. The most important thing there is to make sure that both wings are the same.

So all in all: don't lose any sleep over this at this point. It's too early. You're still in the game.

 

[ditch]

I was hoping I'd get a responce from you Bob. Here's the thing, like I said earlier, vans sent me the wrong plans to look forward so I didn't have the diagram with the measurements on it. Didn't know it was that critical without measurements. I simply measured the 1/2 inch scaled pic and doubled the measurements. Now on the wing that is done, I have 1.5 inches and that would give me 5/8 hole distance, 1/4 inch bolt and 5/8 inch distance after the bolt. Assuming the 1/2 cradle on the fuselage butts completely up against the rib flange. I don't know if they do or not. If all this was true and I drilled exactly perfect, I would have the 5/8 I needed but if of a hair, I wouldn't. Wing sweep would have to be completely back to make the cradle touch the rib flange if in fact it goes back that far.
Anyway, I think I'm in trouble unless by some miracle things would happen to work out. I'll need to replace the right wing plate but like I said, the rear spar is still off the wing. Easy enough.
Why doesn't vans say to leave plenty long and trim when you install the wing? Much less room for this kind of mistake. I'll be leaving the right wing plenty long this time.
I thought about asking if you could build up the edge by aluminum welding. It would work but I assume the properties and strength of the plates would be compromised. Still,probably going to ask. I'm just glad I stumbled across your post or I would have done the right wing wrong too and then I would have had to do what you did. NOT FUN

 

[ditch]

One quick question just to make sure I'm reading you post right. Is the 5/8 distance from center of hole to edge of plate or do you want 5/8 of metal after "edge" of hole? I've been assuming you want 5/8 metal after the edge of the hole. Your one pic looks like your measuring 5/8 from center of hole to edge. That would be great if that's the case but I doubt it.

 

[LettersFromFlyoverCountry]

I was hoping I'd get a responce from you Bob. Here's the thing, like I said earlier, vans sent me the wrong plans to look forward so I didn't have the diagram with the measurements on it. Didn't know it was that critical without measurements. I simply measured the 1/2 inch scaled pic and doubled the measurements.

Yep, I did the same thing. I think most of us do. We just grabbed the dimensions out of the preview plans.

Now on the wing that is done, I have 1.5 inches and that would give me 5/8 hole distance, 1/4 inch bolt and 5/8 inch distance after the bolt.

Remember an important point about edge distance. You're not measuring from the edge of the hole. You're measuring from the CENTER of the hole.

Assuming the 1/2 cradle on the fuselage butts completely up against the rib flange. I don't know if they do or not. If all this was true and I drilled exactly perfect, I would have the 5/8 I needed but if of a hair

I think you're figuring it from the edge of the hole. I think you're actually in pretty good shape at this point.

Wing sweep would have to be completely back to make the cradle touch the rib flange if in fact it goes back that far.

Actually, you may well find you need to file a little to make things fit.

Keep in mind what I had to do in order to be off by only 1/32 in my edge distance:

-1- I had to significantly screw up the measurements
-2- I had to ignore the little "x" I drew in the box I drew indicating where I could drill and be OK (1/2" is a LOT of wriggle room)
-3- I had to drill a hole that went substantially crooked in the direction of the edge of the reinforcing plate.

I did all that and still only violated the edge distance by 1/32.

Anyway, I think I'm in trouble unless by some miracle things would happen to work out. I'll need to replace the right wing plate but like I said, the rear spar is still off the wing.

Nope, I don't think so. Is there anything in the way you cut the hatched area off the reinforcement plate that is inconsistent with the plans?

Why doesn't vans say to leave plenty long and trim when you install the wing? Much less room for this kind of mistake. I'll be leaving the right wing plenty long this time.

Either way you're going to be cutting that plate. Now, I'm not sure how many people cut it oiutside the dimensions in the plan and then put the wing back on, take it off, file and cut, put it back on, take it off, file and cut etc., but the callout in the plans -- done even ALMOST correclty, still gives you plenty of wriggle room.

But I haven't seen anything in your posts that suggests you've done anything wrong.

 

[LettersFromFlyoverCountry]

One quick question just to make sure I'm reading you post right. Is the 5/8 distance from center of hole to edge of plate or do you want 5/8 of metal after "edge" of hole? I've been assuming you want 5/8 metal after the edge of the hole. Your one pic looks like your measuring 5/8 from center of hole to edge. That would be great if that's the case but I doubt it.

Correct, anytime you're talking about edge distance, you're talking about a measurement from the center point of the hole in question. Not from edge to edge.

See here.

 

[ditch]

Thanks for all the help Bob. I measured the one on the right wing and it came out at 1 -12/32" It is shorter but I think I'll call vans tomorrow and ask what they think. I will gladly put a new plate on the right wing as it is so open right now and I now feel much better about the left wing. I was figuring that you needed the 5/8 metal not to center of hole. Going to give myself an ulcer by the time this thing is done.

 

[dhall_polo]

I drilled my rear spars last summer. I cut the spar per plan and thought the drawings had all the right dimensions. Although one thing about the dwgs is that because they give you dimensions from the original shape, once you start to cut, you don't have dimensions you can reference to double check, unless maybe you bought a spare spar part to compare against. (Measure twice, cut once).

Anyway, there is not a lot of room for play, but I think if you cut exactly per plan, most people do end up removing material to get zero sweep. I had 1/4" fwd sweep each side, and I think that required removing 1/16" inch on the spar (exact calc in my notebook somewhere). Note that I ended up with a little (very little) extra above the 5/8" requirement.

My guess is that between the normal amount removed by many builders and the slight builtin extra tolerance to 5/8", you may end about right. Worst case scenario you could introduce 1/8" or so rear sweep each wing and you'd still be well within design limits.

Good luck.