My friend is going to build a Mean Mean Machine Mean Machine (3 mean machine bodies). When he picks it up, it bows in the middle pretty bad, so I suggested to foam the entire thing except the booster section. I was wondering if this would be enough, or should there be more reinforcement. Thanks in advance
Simply gluing balsa stringers (tall toward inside of rocket) would be far lighter and more effective.
The whole project is a bad idea.
Jerry
Hollow carbon-fiber kite stays? Light and very stiff.
That's not overkill. If I built a rocket like that it would have a 38mm motor mount, and that thing would fold under a J570. I have seen many rockets fold in the middle, and a few fold in multiple places. I do like the idea of using longer tubes, and although I am a firm believer in paper, the stiffness of phenolic would help here.
I wouldn't use Great Stuff or any other can foam for 2 reasons. The can foam needs moisture to cure and it is almost impossible to get the stuff from the can into the tubes unless you fill each tube as glue them up.
I built a 5-ft by 24mm superoc and used can foam and it worked ok. But upon inspection after a crash, there were areas that had bubbles & voids.
I have done one with 2 part foam with none of the hassles. I just made small pours about 8 to 10-in at a time. Worked very well.
Nick Stich in Topeka
Jerry's right about this. The balsa ribs are the only way to fly -- I have done this myself numerous times -- but to build a really, really long rocket out of such intrinsically flexible material is a bad idea from the get-go.
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.