Two stage idea tube fin

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chris m

Well-Known Member
May 24, 2013
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Hello idea that I will test out soon . 24 or 29mm two stage BP to start . May do MD just to make simple . The idea tube fins work best at 1-3 caliber ( 1-3 diameter tall ) first stage at 1 and booster at two . Sim out not bad but it's not real world . Will start small then work up . Not looking for speed or altuide just want to do something not everyone else is doing . Should be fun . Will post a sim when I have time .
Don't think I've ever seen a two-stage tuber. Should be fun.
Two stage tuber works great. If you're pushing Mach .8 or better keep the outside length of fin < ID to prevent flow choking inside the tubes.

Once you pop through about Mach 1.2 you'll be in great shape. You can sweep the forward edge to reduce CD and strengthen the fins a bit, but be aware you've thus created a scoop. You're also going to see your tuber weathercock more than they typically do.

If you want to go high Mach, 7 fins is better. I have a pretty extensive list of tube compatibilities for 3-9 fins, 5/6/7 being the sweet spot.

d21-4 to c6-7 should be doable, though I haven't tested it yet. Enjoy&#8203; the tubers! My someday is to fly a naked m1378 with a cute little 7-fin skirt :)
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That's very cool . I don't like to do the same as the next person . I'm card board and wood glue and epoxy only when I have too . I'm thinking with tube lenght half to one caliber may be the sweet spot . My tests will be with estes tube and NC there cheap so it would be a good test bed
I will play around with this first test in bt 50 and see how it does
Sounds like a fun project--look forward to hearing more about it as it develops!


Yes learned a lot from my first tube fin project the super evil minon a 4 inch that I had the fins way to long . Boost was fine first 300 ft or so and hit its wall
So I was going to pick up some 24 mm tube , will not go with estes stuff thin junk . Now have to see who make a cone for 24mm loc
So I was going to pick up some 24 mm tube , will not go with estes stuff thin junk . Now have to see who make a cone for 24mm loc

What about LOC mini missiles. Think they are on closeout so may need to grab em up.
That is a good idea or thinking about 38mm tube . And with that have recovery on both