Fillets or tab-to-tab fiberglassing?

[amiliv]

A bit of a fiberglassing newbie question. I was just about to start putting internal fillets on a fincan for 3" LOC Iris. Then thought to maybe try fiberglassing tab-to-tab instead of doing fillets. I don't plan on adding not needed weight by overbuilding the rocket, and was wondering if tab-to-tab fiberglassing would be more or less weight added than internal fillets would add? Would fiberglassing the joint add more or less structural integrity to the joint compare to only fillet?

For fillets, I'd estimate probably about 10-ish grams of epoxy per fin, depending how thick I make them. Note that I don't have much experience fiberglassing, so not much feel how much weight fiberglassing would add. If fiberglassing, the end result would look something like the mock on the attached photo, just with fiberglass cloth where the mock made out of paper is.

IMG_20190430_081026

• amiliv
• Apr 30, 2019

 

[Theory]

fillets first, always fillets first as glass does not provide much strength when it is asked to make a hard 90 degree bend. then, if you want glass on top, though, I cannot see you needing that much strength as the plywood or cardboard body tube will fail long before internal and external fillets will.

 

[amiliv]

Thanks Theory. I think i'll stick with just doing regular internal and external fillets in that case.

 

[cwbullet]

Unless flying at Mach+, I rarely find fiberglassing necessary.

 

[dr wogz]

For a rocket this size, TTW tabs & regular glue fillets is fine.