While rockets launched from silos are generally weapons of war, [Joe Barnard] of [BPS.Space] thought model rocketry could still do with a little more thoomp. So he built a functional tube launched model rocket.
Like [Joe]’s other rockets, it features a servo-actuated thrust vectoring system instead of fins for stabilization. The launcher consists of a 98 mm cardboard tube, with a pneumatic piston inside to eject the rocket out of the tube before it ignites its engine in mid-air. When everything works right, the rocket can be seen hanging motionlessly in the air for a split second before the motor kicks in.
The launcher also features a servo controlled hatch, which opens before the rocket is ejected and then closes as soon as the rocket is clear to protect the tube. The rocket itself is recovered using a parachute, and for giggles he added a tiny Tesla Roadster with its own parachute.
Projects as complex as this rarely work on the first attempt, and Thoomp was no exception. Getting the Signal flight computer to ignite the rocket motors at the correct instant proved challenging, and required some tuning on how the accelerometer inputs were used to recognize a launch event. The flight computer is also a very capable data logger, so every launch attempt, failed or successful, became a learning opportunity. Check out the second video after the break for a fascinating look at how all this data was analyzed.
[Joe]’s willingness to fail quickly and repeatedly as part of the learning process is a true display of the hacker spirit. We’ll definitely be keeping a close eye on his work.
2nd vid 1:05… before they make it shoulder launch, they need to work on that targetting computer, missed the quadcopter by quite a bit :-p
https://www.youtube.com/watch?v=oXJvOJNUlCs
Video banned already lol.
Video title “How to get yourself on a watch list and make a itar restricted item.”
Don´t tell AlQuaida ;-)
I suspect that having a guidance system in this moves it into the “munitions” category, and any design information is subject to export controls. An amateur rocket with no guidance system isn’t controlled, things that can steer, are.
There’s a subtle dividing line for export control — active stabilization, which only tries to keep the rocket pointed in a certain direction, is unrestricted. Active guidance, which tries to fly the rocket to a particular location, is restricted. As long as you stick to “point this end toward space” and not “travel this far upwind to shorten my recovery walk,” ITAR keeps its hands off.
Oh cool, so you can blaze away randomly against large civilian targets like populous cities V-1 style, but tightening things up to make sure you only hit military targets is forbidden LOL
Why the piston? I mean, if you want a pneumatic launch, why not cut down on the moving mass by just having a gas check behind the rocket?
That was my thought also. More like a mortar.
My guess? It would pop the parachute.
It’s pointless. Just throw the rocket up in the air. Same result.
Definitely smacks of kewl! Well done! What’s next, launching from under water ?
:)
Why didn’t he just use a wire to pull a switch to ignite the rocket, much simpler.
Steampunk style … Engage two emery boards either side of a lucifer match with a binding of india rubber thread, and by means of an attached cord to them and a fixed point cause the momentum of the projectile to strike the lucifer against the abrasive surface thus igniting the propellant powder by so doing…. with some brass gears on.
Nah, I look terrible in a handlebar mustache.
Or just use a fuse as a time delay element. The fuse can be lit just before launched from the tube. :P
Was a little worrying when the rocket engine started on the ground. If it fell slightly differently it’d have torched the big gas canister…
Am I the only one who thinks he looks like Elon Musk?
No, I think the same.