• Welcome aboard HomebuiltAirplanes.com, your destination for connecting with a thriving community of more than 10,000 active members, all passionate about home-built aviation. Dive into our comprehensive repository of knowledge, exchange technical insights, arrange get-togethers, and trade aircrafts/parts with like-minded enthusiasts. Unearth a wide-ranging collection of general and kit plane aviation subjects, enriched with engaging imagery, in-depth technical manuals, and rare archives.

    For a nominal fee of $99.99/year or $12.99/month, you can immerse yourself in this dynamic community and unparalleled treasure-trove of aviation knowledge.

    Embark on your journey now!

    Click Here to Become a Premium Member and Experience Homebuilt Airplanes to the Fullest!

Rib design and rib stitching

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

olgol

Well-Known Member
Joined
Nov 13, 2007
Messages
85
I would like to hear some opinions about alternative rib designs for ultralights with front and rear tubular spars, and how they are related or suitable for attaching the top covering to the ribs. Here are some questions/thoughts that I would like to discuss:

1. Is rib stitching needed on true ultralights? Do you rib stitch your wings? I understand that most of the UL planes do not have rib stitching. In level flight and probably up to a load factor of 2g, it is unlikely that the top covering would lift off the ribs, although I have no way of verifying this. But at higher load factors (a pull-up at 3-4g) I am sure the covering will lift off the ribs. Which again may be no big deal at all.

If the general opinion is "forget rib stitching" on UL planes, then the following questions do not apply. Any rib design will do.

2. If we assume that the top covering must be attached to the ribs either via rib stitching or by gluing it to the ribs, then ribs made from round tubes (typical rib design on UL planes) are not the best option. Gluing is not going to work at all, rib stitching will pull the covering around the tubes and will produce deep ridges along the ribs.

3. If the above (2) is correct, ribs must have a flat flange of some sort. Then rib stitching or gluing the top (and bottom?) covering is easily done.

4. Wooden ribs although technically possible, would not be my choice with aluminum tubular spars.

5. Foam ribs with plywood/wooden caps (affordaplane, SkyPup) are another alternative. Although seemingly low tech, reports claim they have great strength to weight ratio. I am a little concerned about longevity of such ribs and their resistance to accidental bumps and minor ground handling abuse. If the foam is crushed under the rib cap, a rib may have to be replaced (and the wing covering opened).

6. Has anybody seen "standard" aluminum stamped ribs used in UL wings with front/rear tube spars? I know such ribs are used on airplanes with "normal" spar/D-tube wings, like N-3 Pup, etc. This rib design to me seems the most professional, although probably the most difficult to manufacture at home. Does anybody know of manufacturers that can produce/supply custom designed stamped ribs?

Thanks in advance for your opinions and suggestions.
Oleg.
 
Back
Top