Post by flydiver on Mar 13, 2007 3:13:14 GMT 1
I got a 2nd hand Cub from a guy that crashed his first one and did OK on the 2nd one before moving on to another plane. He didn't have the wing struts or the attachments. He thought they weren't necessary I flew it conservatively for a couple weeks and did some research in RCGroups and Wattflyer and found some opinions that they were needed but a pain to deal with. They also seem to be partly responsible for ripping out the battery box.
I have a Slow Stick that reinforces the floppy foam wing with a aluminum brace and fiberglass or carbon spars. So I got some 5/32" brass tubing and 3mm carbon. I bent about a 4" piece of the brass to the shape of the wing dihedral and cut 2 carbon spars (Dremel tool) a tad longer than the wing. I measured back about 1/3 of the wing chord and cut a straight groove with my table saw and fence guide the entire length of the wing deep enough for the spar. Then I glued in the brass/carbon reinforcement using Gorilla Glue once I made sure it would go in without twisting or deforming the wing in any way (IMPORTANT). I held it in with blue painters tape until it cured.
Gorilla glue "kicks" with moisture. Mix in a little or some Elmer's glue in to get it going. It foams up while curing so you don't need much. Sumo glue is a similar product that is supposed to be a little more white and foam less. I think you could use foam safe CA (superglue) also.
I saw a hint to poke some small holes in the cover tape while the glue is curing so the extra foam/glue can get out. Then you just peel it off and sand a bit to clean up.
Once done cover it with strapping or packing tape. Of course I cut off the little bit of carbon sticking out the end of the wind. You don't have to run it all the way to the end if you don't want.
Since then I have done inside loops, outside loops, spins, and flown upside down in up to 10mph+ wind without a problem. I'm also using a BIG battery pack (7-cell, AA/1400 MAh - have to rubber band the battery door mostly closed) so it is sustaining a bit more weight than normal during this.
Seems to work. No struts to deal with.
Groove cut and taped off with brass and carbon spar below. Glue in slot.
Close up of spar in wet glue before taping over.
I have fixed a completely broken Aerobird wing with this technique but using bamboo BBQ skewers. It's not given me any hint of breaking. I think it's stronger than new (but a tad heavier).
flydiver
I have a Slow Stick that reinforces the floppy foam wing with a aluminum brace and fiberglass or carbon spars. So I got some 5/32" brass tubing and 3mm carbon. I bent about a 4" piece of the brass to the shape of the wing dihedral and cut 2 carbon spars (Dremel tool) a tad longer than the wing. I measured back about 1/3 of the wing chord and cut a straight groove with my table saw and fence guide the entire length of the wing deep enough for the spar. Then I glued in the brass/carbon reinforcement using Gorilla Glue once I made sure it would go in without twisting or deforming the wing in any way (IMPORTANT). I held it in with blue painters tape until it cured.
Gorilla glue "kicks" with moisture. Mix in a little or some Elmer's glue in to get it going. It foams up while curing so you don't need much. Sumo glue is a similar product that is supposed to be a little more white and foam less. I think you could use foam safe CA (superglue) also.
I saw a hint to poke some small holes in the cover tape while the glue is curing so the extra foam/glue can get out. Then you just peel it off and sand a bit to clean up.
Once done cover it with strapping or packing tape. Of course I cut off the little bit of carbon sticking out the end of the wind. You don't have to run it all the way to the end if you don't want.
Since then I have done inside loops, outside loops, spins, and flown upside down in up to 10mph+ wind without a problem. I'm also using a BIG battery pack (7-cell, AA/1400 MAh - have to rubber band the battery door mostly closed) so it is sustaining a bit more weight than normal during this.
Seems to work. No struts to deal with.
Groove cut and taped off with brass and carbon spar below. Glue in slot.
Close up of spar in wet glue before taping over.
I have fixed a completely broken Aerobird wing with this technique but using bamboo BBQ skewers. It's not given me any hint of breaking. I think it's stronger than new (but a tad heavier).
flydiver
They really flexed.
