Rib lengths?

[Barry]

I am ready to cut my ribs using the router method. I am following Eric's book page by page and am enjoying every minute of this build! I do have a question, in the book he says that you can cut all the nose ribs the same length and cut the shorter ones to length later on because of spar thickness. Wouldn't it be easier to cut them to length now on the router that using shears later on? Does anyone have a list of measurements for all the rib lengths. I know I should figure this out reading the plans, but I thought someone may have these numbers.

Thanks,
Barry

[DesertBearhawk]

Barry, Im not building a Patrol so I am sure my measurements are not the same for the Patrol but I did cut each of my ribs to proper length as I was building them. I think this will end up being a better/cleaner way to go when I assemble the wing. You will have more time in tooling but I think its worth it.

[X'N]

I cut all my ribs to length but I also used a cnc router to do the cutting. There are a bunch of different lengths. There are 3 different length nose ribs, There are 7 different length center ribs here are the ribs that I came up with that are the same length #2 & 5 and 6-10 are the same but all the rest are different. I believe it was on the old yahoo forum that someone showed pictures of their method for cutting the ribs to the correct length. They stacked layers of aluminum on the ends of the forms and would add or remove layers to trim the ribs to the correct length.

[N3UW]

I cut all my ribs to length but I also used a cnc router to do the cutting. There are a bunch of different lengths. There are 3 different length nose ribs, There are 7 different length center ribs here are the ribs that I came up with that are the same length #2 & 5 and 6-10 are the same but all the rest are different. I believe it was on the old yahoo forum that someone showed pictures of their method for cutting the ribs to the correct length. They stacked layers of aluminum on the ends of the forms and would add or remove layers to trim the ribs to the correct length.

For my patrol ribs I went through the plans and figured the length of the ribs for each location. I then cut my rib router template 1/4" short. I then made 1/8" and 1/4" wooden shims that screwed to the end of the noses and center rib forms. I then router the ribs to the needed length. I did make one extra full length rib of each size just in case I messed up one. It worked very well. I think I showed what I did on one of my videos I put on youtube. here is the link

[Barry]

Thanks for everyone's input on cutting the ribs. I will be cutting them to length now, I agree that it will make for a cleaner cut using the router, even though there is more tooling to do.As for the lengths of ribs and locations, I figured that out using the plans. I will use John's method of cutting the ribs using my router. Thanks again!!

[Cherokeedriver]

John, thanks again for the video. I'm curious, did you consider using the press/hydro from method to form the flanges on the top and bottom of the rib at the same time you were forming the flanges for the lightening holes?

[N3UW]

John, thanks again for the video. I'm curious, did you consider using the press/hydro from method to form the flanges on the top and bottom of the rib at the same time you were forming the flanges for the lightening holes?

I tried it but the the press did not seem to have enough power to press the rubber all the way around the form block. It did for smaller ribs though like the flap and aileron ribs. Possibly a 40 or 50 ton press would work. Also I originally tried with a softer rubber. That rubber ripped and I bought a harder (60 hardness I think) polyurethane rubber that was much tougher. It worked better but by that time I had already flanged all of my rose ribs.

[Gunpilot]

Looking into using this process for my wing ribs. Anybody know where I can by the rubber and what type to by

[N3UW]

Looking into using this process for my wing ribs. Anybody know where I can by the rubber and what type to by

I ordered it from McMaster Carr. Part number 8789K81 with a hardness of 60A. The material is 12"x12"x1" Amber polyurethane I also ordered a sheet of 8568K9 50A Neoprene to make it thicker. I put the neoprene between the metal plate and the poly sheet. the neoprene itself would not work against the AL part because it would tear but it worked great as a backer block and was cheaper.

[Gunpilot]

Thanks alot

[Chris In Milwaukee]

That's some spendy stuff, isn't it?

[N3UW]

That's some spendy stuff, isn't it?

It is. glad I did jot need 6" of it. I have bee using it to form a lot of parts though. I am a bit of a tool junkie though!!!

[geraldmorrissey]

Just a cautionary note, Cutting parts to net dimensions long before you need them is not without it's difficulties. I don't think cutting the rib lengths is an issue, it's been done successfully. However net trimmed parts leave you little room for adjustment. And you may need that adjustment from component positional tolerance, material tolerance, tooling tolerance plus stuff you just didn't see because you didn't look far enough ahead. All this stuff stacks up and can leave you painted into a corner with no options. Leaving some extra material and trimming on assembly will let you sleep better at night. When I see this advice to new builders "just concentrate on one piece and move on to the next" it makes me wish I was a fly on the wall during assembly.
Cheers
Gerry
Patrol #30 Wings

[Phil]

I'll second that. The final length of the ribs will be set by the flap and aileron support brackets. So I'm holding off trimming my till I have those welded up and assembled with the spars.

[Barry]

I will let you know how it turns out, I have already cut all my rib lengths to net length. I had various opinion to this, and I decided to cut all mine to length. I have purchased the support brackets from Bearhawk so I hope they are the proper length as per the plans. The brackets have not yet shipped. I also read that Bob Barrows said if the rib is a bit short, you may cheat it out some as long as rivet distance is in check. I will be posting pictures and a build update soon. Thanks for the advise.