Eagler's Nest

Airframes => Double Seaters => Topic started by: ToddK on June 16, 2015, 09:33:30 PM

Title: Wing Rib Jig Tolarances
Post by: ToddK on June 16, 2015, 09:33:30 PM

Hi all, 
I am a new builder, is it a problem if the wing rib is 1mm two short from top to bottom in the middle section? 
Thanks

Title: Re: Wing Rib Jig Tolarances
Post by: MrG on June 16, 2015, 09:45:10 PM

1 or all ?
i would really doubt you would know the difference 
you will be buying .9 ply to do other stuff you could always add strips and glue

Title: Re: Wing Rib Jig Tolarances
Post by: ToddK on June 16, 2015, 09:54:50 PM

It's the jig.  I glued the full size rib pattern down, and in doing so put a gentle 2mm sag in the middle.  I drew the bottom strait, and corrected for it at the top, but came out a 1mm two short.  The Jig is nearly finished.

Title: Re: Wing Rib Jig Tolarances
Post by: Tom XL-7 on June 17, 2015, 03:58:09 AM

Every builder puts his own little fingerprint on his parts. You used a full size pattern, I used photo copies of Leonard's photo copies then cut and fitted up. I would bet that there is more than a "mm" difference between us. Both of us should be OK. Now if I solicited  a single rib from 26 site members to build my XL I would have a comical mess on my hands.
  Part of getting older is ... well getting older. I sag more than 2 mm for sure but I don't think I have a reliable reference point to measure from.
Now that was letting you off real easy. Don't be a tird; read your post before you send. Spell check wouldn't have caught that one.
Tom XL-7

Title: Re: Wing Rib Jig Tolarances
Post by: ToddK on June 17, 2015, 06:10:27 AM

Thanks Guys.  
It took me a sec to realize what I wrote.  I sincerely apologize for the typo.  I thought the word looked off, and have corrected it.  No more posting past 10pm for me.

Title: Re: Wing Rib Jig Tolarances
Post by: MrG on June 17, 2015, 03:06:13 PM

Todd you use MM - were r u

Title: Re: Wing Rib Jig Tolarances
Post by: ToddK on June 18, 2015, 08:56:31 AM

I am in Houston TX.  While in college, I worked an industry where the metric system is the norm.

Title: Re: Wing Rib Jig Tolarances
Post by: boba65$# on June 18, 2015, 09:09:31 AM

I built my own jig.....very ridgid.and made them all within very close tolerances........I think EVERY homebuilt is a little different. Lets not forget that these arent certificated, factory units/components made on some hydro-press/forge. Just make sure that YOUR ribs are identical for YOUR craft. Build your wings AROUND YOUR ribs. When I worked as an A&P (Continental Airlines), some of our commuter planes, specifically  some Embraer  models  had MANY components that were not "JIG-BUILT". It's not like we are chambering a rifle barrel, where .045 could kill you .  Obviously. there is NO excuse for sloppy work, but the parameters for "airworthy-acceptable" is fairly wide in most low-speed/high-drag designs.Copy/reproductions on computer printers/Office Max, Kinko's, etc .DO PRODUCE some variables in final the  product(if you are using these copies for production patterns). If you are not an A&P, study the builders plans carefully, and FAA circular 43.13 1B, and other A&P reference guides  for legal build standards. Spend $25 on Amazon and get BOTH 43.13 circulars(actually 2 books). When manufacturers criteria does not exist....these publications are FAA LEGAL for repairs/construction/alteration. Full of VERY interesting info.

Title: Re: Wing Rib Jig Tolarances
Post by: Dan_ on June 18, 2015, 11:38:47 AM

If your internet connection is up to the task you can download both at the clicks below...

http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC43.13-1b.pdf (http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC43.13-1b.pdf)  20 meg


http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC%2043.13-2B.pdf (http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC 43.13-2B.pdf)  6 meg