Factory rib joggles

[Phil]

I'm getting ready to bend my spar channels for my Patrol later this week, and noticed that the joggle at the front of my factory center ribs is only 1" long. The plans call for 1-1/4" flanges on the main spar. Do I need to extend the joggle another 1/4" so the ribs can touch the spar web, or just use longer attach angles for the outer ribs, stations 13, 14 and the tip rib and hold them a 1/4" off the web?
Thanks.

[Chris In Milwaukee]

Recall the spacing added by the spar caps (1/4" on the Bearhawk 4-place). I presume that it's similar on the Patrol? And then some wiggle room for alignments. Would that take care of it?

[Phil]

It is the same on the Patrol, however, the cap strips stop short of the wing tip, so the attach angles for the last 2 ribs and tip ribs are riveted directly to the spar webs.

[Chris In Milwaukee]

Are the ribs all the same size, or are they sized per position? I suspect you'll use longer attach angles there. 4-place is similar unless you cut the ribs different sizes.

[Phil]

All the ribs came from the factory the same size.

[mswain]

All the ribs came from the factory the same size.

If you lay them over the Mylar full size rib drawing....can you tell how they are sized? I think the 4 place center rib from the factory were 1/8 short front and rear from full size. They had to be trimmed where cap strips were 1/4, no trimming at 1/8 cap strips, and they were spaced 1/8 from the web out towards the tip where there are no capstrips. No trimming on the rear of the center rib since the rear spar is 1/8 the full length.

[Phil]

Good idea. I'll check them against the template tonight. Thanks.

[sjt]

I also need to bend the spar. I have not had very good results on my test pieces. I would very much like to know what you used to get the rounded corners. Bob's manual says make a 5 inch wide foot cover. I tried the roof flashing that can be purchased at Home Depot, but the radius of the foot cover is as sharp as the original brake. If you find a material that works better then flashing, I would like to know what you find.

[Phil]

I checked the ribs against the full size template, and they extend right up to less than 1/16" from the spar center line. So I guess I'll be building a tool to extend the joggle on all my ribs an extra 1/4".

[mswain]

I checked the ribs against the full size template, and they extend right up to less than 1/16" from the spar center line. So I guess I'll be building a tool to extend the joggle on all my ribs an extra 1/4".

I would give Mark a call. I can't imagine the factory has to tweak every joggle. Maybe he has the info to save you some time.

[Phil]

I'm planning to do just that. I'm afraid, that since my ribs were from the first run, that maybe they identified and corrected this problem years ago.

[Phil]

I talked with Mark yesterday, who directed me to Bob Barrows. Bob suggested that the easiest solution would be to make my spar webs with shorter flanges. As long as I can maintain edge distance for my rivets he said it would be fine. The only problem he anticipated was that bucking the rivets along the thickest parts of the spar lamination could be tricky.

[dedgemon]

phil, i think there will be room, but you'll have to be more carefull laying out the rivets and building the skins. it might be a lot simpler just to lengthen the joggles. a simple joggle fork and a vice is all it takes. I didnt do this on mine but honestly dont remember the length of the joggles. I'll try to go out tonight and measure them. I would highly recommend 5/8" angles instead of the 1/2". makes alignment a little easier with a little more wiggle room.

[dedgemon]

phil, my joggles are 1", which works just fine. I used 1/4" worth of spacer on each rib (all the way to the tip).

[Phil]

David, Thanks! When you say you used 1/4" of spacer, do you mean you riveted in 1/4" thick spacers under each attach bracket, or just used longer attach angles near the tips?
Thanks again.