12/2/12

Spin Stabilization

Not sure if this has been  done before, but I've just recently had a new idea:

Spin stabilization has been a concept that's been around in rocketry for a long time. But just how fast can you spin a rocket, and just how far can you benefit from it? Do you even need fins at all if you get it spinning fast enough? Take a look at a bullet, for example. It has no fins. It is, however, exiting it's "launch tube" at supersonic speeds, but perhaps this can be related to rocketry.

I imagined a launch pad that uses an electric motor to spin the rocket extremely fast, say... 1000 rpm. One point of concern is the electrical leads for the igniter. You would need to use some sort of conducting bearings, or even an onboard ignition system triggered wirelessly.



Just a thought.

The main question I would like to look into is: Can spin-stabilization be effective enough to have a rocket with no fins? At what angular velocity? With what kind of rocket geometry?

7 comments:

Dick said...

I know there a guy who spun a football shaped rocket prior to launch. I can't remember where I saw this. You might try TRF or Google. It may have been an actual football. If you can work out the mechanics, it would be a cool experiment.

Dick said...

Found it. It was older than I remembered.

http://www.rocketryforumarchive.com/showthread.php?t=49339&highlight=football

DTH Rocket said...

Okay, thanks! That's pretty neat. Might be interested in finding something on the theory behind it, but for some reason it usually is about bullets and not rockets. Or maybe just some qualitative information that is already pretty obvious. But thanks for posting that, I've never seen it before.

High Power Rocketry said...

Yes, team Prometheus made a spinning rockoon tower:

http://nprize.blogspot.com/2009/10/team-profiles.html

And the Super Loki Dart spun up in a helical launch tower:

http://www.phy.mtu.edu/rocket/superlok.html

I think the passive method, the latter, is better. Simple and light-weight.

High Power Rocketry said...
This comment has been removed by the author.
High Power Rocketry said...

*Additional*

One should note that spin alone does not work well for long rockets, eg rockets with a 10:1 ratio. They should have fins and spin. Long objects tend to convert that kind of spin (is it axial?) into an end over end tumble.

In bullets, the length to width ratio is much smaller, like a football. Bullets, you should know, also rotate extremely fast. Many hit 100,000 rpm. Rockets are fine with just 100 - 300 rpm, but they do generally need fins also.

Dick said...

Lots of professional rockets are made to spin. @HPR...great point in the 'additional' comment.

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