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maya.ayoub.32

Well-Known Member
HBA Supporter
Joined
Apr 6, 2020
Messages
78
intuitive feel for space frames
We did this! We used kebab sticks and hot glue to make the frame and it's actually a lot more sturdy than we thought it would be. We added 2 beams that this forum recommended, going from the front triangle to the side of the cabin which we felt was necessary after adding a "lift" force on the model.
Image from iOS (12).jpg
Does anyone else have any further suggestions on the design? We feel confident enough to call it done at this point if not.
 

Gregory Perkins

Well-Known Member
Joined
May 25, 2019
Messages
131
Location
Atlanta
We did this! We used kebab sticks and hot glue to make the frame and it's actually a lot more sturdy than we thought it would be. We added 2 beams that this forum recommended, going from the front triangle to the side of the cabin which we felt was necessary after adding a "lift" force on the model.
View attachment 112492
Does anyone else have any further suggestions on the design? We feel confident enough to call it done at this point if not.
Kabab CAD is a lot easier than computer CAD isnt it :) ........ regarding entry to the cabin, perhaps one end of the tube blocking entry could be hinged on one end with a connector on the other end allowing for a door swing 03.JPG++j3-11.JPGopen function. Or connectors on both ends allowing for full removal of the cabin tube instead of swinging open on a hinge. I am attaching photosj3-06.JPG of the frame for a small single seat UL called the J3-Jr
simply for comparison.
 
Last edited:
Joined
Jun 21, 2021
Messages
7
Hello Homebuilt Forum!

First off, thank you so much for all your help. We received our 3/32" 7x19 galvanized control cables (3/32" 7x19 Galvanized Aircraft Cable - 1050 lbs Breaking Strength) but recently realized that they're not aircraft certified. Their breaking strength of 1050 lbs is far above the forces we expect them to take and the same cables (but certified) from aircraft spruce (CONTROL CABLE | Aircraft Spruce) are 6 times the price. Is it worthwhile to switch to aircraft spruce's cables?
 

rtfm

Well-Known Member
Joined
Jan 3, 2008
Messages
3,653
Location
Brisbane, Australia
Personally, I'd go with the cables you have. I didn't even bother with Aircraft certified cables. Just bought good ones from the local boat supply store. I think this "certified only" mantra is more superstition than anything else. Buy good kit and get on with it.
 

delta

Well-Known Member
Joined
May 26, 2011
Messages
2,512
Location
Brookside Utah
Hello Homebuilt Forum!

First off, thank you so much for all your help. We received our 3/32" 7x19 galvanized control cables (3/32" 7x19 Galvanized Aircraft Cable - 1050 lbs Breaking Strength) but recently realized that they're not aircraft certified. Their breaking strength of 1050 lbs is far above the forces we expect them to take and the same cables (but certified) from aircraft spruce (CONTROL CABLE | Aircraft Spruce) are 6 times the price. Is it worthwhile to switch to aircraft spruce's cables?

Probably not a factor but could be... the fatigue characteristics and temper variation between the two alloys. A larger diameter pulley would reduce friction if nothing else.
 
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