Help with a styrofoam cup build

[CKaul04]

I was looking into the Flis Decafinator, but they went out-of-business before I could order one. Many small styrofoam cup at my disposal. Every website is sold out of the big foam rockets.

Colin

 

[Sooner Boomer]

How tall of one do you want to make? Balsa Machining Service has body tube sections in 18" and 34" lengths. Pick the appropriate diameter,mMake a jig to center the hole on the bottom of the cup, then start cutting, stacking and gluing.

 

[CKaul04]

Thanks, will try soon

Colin

 

[Gus]

Decaffeinator and Espresso were both rear ejection models. For the Espresso the main tube was BT50, just long enough to hold the BT5 motor mount, a streamer, and a shock cord attached to a front bulk-plate or plug. The tube went up through the first three cups, then the rest of the cups were just hot-melt-glued to each other, as high as you would like. Fantastic design.

13 years ago my daughter built 5 Espressos for a Science Day demo launch at her school. Attached are photos of her build which should give you an idea of how they go together.

I also never miss an opportunity to thank Jim Flis for this design which taught my daughter and I about rear ejection rockets. It was the first time we'd ever done it. We've used the technique lots and lots very successfully ever since. Last two photos are of the same kid and her somewhat more sophisticated two stage double rear-ejection model at this last summer's World Spacemodeling Championships in Poland. Her team, with a couple of slightly older teammates, finished third in the world!