Decided on placement for the outer rib: 139" from the spar tube end. I also added 2" to the inner spar tube, so the inner rib is at 70" from the spar tube end. The compression ribs are spaced evenly in the remaining distance. These placements weren't scientific, rather admission to myself that other Goats built to these drawings are flying and doing fine. If there is a problem with the dimensions I've chosen, I'm counting that it'll show during the load test.
Need to start thinking about making strut connection brackets on the cabane end and also how to get the final strut lengths (incl matching washout angles between the two wings).
3 comments:
Hi Dan,
Good to see you are progressing with the build.
Just keep in mind that with the strut based goats the sleeving at the strut junction is providing cantilever strength to the wing.
The wire braced goats don't need as much sleeving because the support wires are attached out further supporting more of the wing.
As you noted G3 used 36 inches and in comparison G1 used 66 inches.
I used 66 inch sleeves with thicker sleeves and spars on the Yando Goat, but then again I was catering for a 90kg pilot:)
I think a lot of builders/potential builders will be interested in your load testing when it happens.
cheers Alan
Thanks for the reminders Alan. I'd say it's a balance between practical experience and engineering, but without Sandlin's calculations (might he provide!?) or duplicating them, it's just experience. Might be time to actually do the math.
If it helps offset some concerns, I did also increase the spar wall thickness as you did. And the wing tip isn't nearly as heavily loaded as the root sections, most especially if there is any washout.
I'll make sure I do the math before it gets impossible to change the outer sleeves to longer/thicker.
I should do some math on this rainy day.
Thanks Alan (and very much loving your videos on youtube!)
You know what, I'll add that it's a balance also to flying hardware, which you have. That goes an awful long way.
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