Author Topic: ribs (Read 1472 times)

roger gebhart · « **on:** December 04, 2006, 08:36:45 PM »

I use aluminum templates when building multiple ribs. I find that when building for a tapered wing the trailing edge of the ribs is very steep and pointed. How do you handle that.? Maybe extend the rear of the template a bit to allow for trimming the proper angle and length?

rog

Jim Thomerson · « **Reply #1 on:** December 10, 2006, 06:40:44 AM »

I don't understand your problem. If you could elaborate a bit maybe we could help. Do you make all your ribs using one template? There are a series of airfoil curves called simplex curves which give you the same airfoil no matter the chord. I think they can be found on line but don't know where.

roger gebhart · « **Reply #2 on:** December 10, 2006, 03:57:00 PM »

Boy I sure didn't make that very plain. I use a root template and a tip template and sandwich the ribs in between to shape them. If the wing tapers much when I pull the ribs apart the trailing edge is not square with the rib as I spread them out. Where the !/4 " t/e stock and the rib join is where I run into problems. The but of the rib tapers much faster in the stack than it does on the wing and leave a pretty poor fit. Am I making any sense here cause it sure doesn't to me when I read it back. But it still don't fit right with out some help. rog

Jim Thomerson · « **Reply #3 on:** December 10, 2006, 05:29:10 PM »

OK, I see what you mean. I've run into the same problem on a severely tapered wing. I think I mitigated (not solved) it by getting the ribs roughed out and then putting 1/2 inch foam spacer blocks betwen them and using a long sanding bar.

Actually your problem with stacking ribs is real, but usually ignored. The individual ribs comes out tapered in thickness from what you want to less than you want. I think you could solve this by making the root rib template the next bigger rib, rather than root rib size. That way when you sand the ribs square they would be the right size. Does that make sense?

RC Storick · « **Reply #4 on:** December 10, 2006, 05:33:47 PM »

Quote from: Jim Thomerson on December 10, 2006, 05:29:10 PM

OK, I see what you mean. I've run into the same problem on a severely tapered wing. I think I mitigated (not solved) it by getting the ribs roughed out and then putting 1/2 inch foam spacer blocks betwen them and using a long sanding bar.

Actually your problem with stacking ribs is real, but usually ignored. The individual ribs comes out tapered in thickness from what you want to less than you want. I think you could solve this by making the root rib template the next bigger rib, rather than root rib size. That way when you sand the ribs square they would be the right size. Does that make sense?

I add 4 more, two on each side and square up the ends and they come out right everyother one.

rustler · « **Reply #5 on:** December 11, 2006, 04:05:36 AM »

You could set the ribs square at the l.e. (or angled to match the actual angle of the wing) and sand the front half of the rib, then set the t.e. similarly, and sand the back half. Good luck.

roger gebhart · « **Reply #6 on:** December 12, 2006, 04:35:03 PM »

Ok I know you think I might not have read all this, but I did. All soud like good ideas. I like the 1/2" foam spacers. Sound like they might make the whole process easier and more accurate. Thanks to all rog

Author Topic: ribs (Read 1472 times)

roger gebhart

ribs

Jim Thomerson

Re: ribs

roger gebhart

Re: ribs

Jim Thomerson

Re: ribs

RC Storick

Re: ribs

rustler

Re: ribs

roger gebhart

Re: ribs