Spin Stabilization

Make sure your body tube doesn't unwind!

See this video for a demonstration of why!

This was about 8 or 9 C's round the outside and an F or G in the middle.

No but either canting the motors or putting small vestigule fins at an angle, works.

2+ fins.

Don't use a rail. Use a rod, tower, or piston.

Pistons rock.

Jerry

I think it was on the CATO website, someone had a rocket like that with 1 White Lightning motor and 1 BlackJack that made very pretty corkscrew smoke trails.

Or tube...

Steve Randall of EARS has an interesting discarding sabot rocket that really cooks out of the tube on a 'mighty' D12 - with a lightweight sabot I guess that approach could be even better than the piston. Any ideas?

I especially liked the traditional British understatement at the end: "interesting"

It will fly again! They said the Scroton would never work.

Chris

My idea is that that sounds quite cool. Is there any design information available? Is the purpose of the sabot to protect the rocket against back blow from the exhaust while its still in the tube?

As opposed to the NASA understatement of 'we've had an anomaly' when a Delta II became a vast fireworks display. I'll have to fish out the link for that one. :-)

Another one that might amuse you:

Shame about Mike's rocket, but listen carefully at about 17 seconds...the immortal words of Richard Parkin ;)

As far as I know, the sabot forms a gas seal (well, there will be a tradeoff between seal and ease of movement) in the tube, and the expanding gases from the motor force the whole lot out the tube, fast - just like a piston launcher. Sabots are used on guns (probably the wrong term - artillery perhaps?) to allow a small, light projectile to be fired *very* fast from a weapon normally used to fire a heavier shot more slowly.

The sabot will provide some protection, but as I understand it its main purpose is to make the most of the exhaust gases - specifically those that usually go into making that big flat cloud of smoke as the motor pressurises.

I have some photos of it somewhere, I think its an ongoing development project.

Try:

and Having seen how a sub-minimum diameter rocket moves on a D12 (when the UKRA records are next updated, there should be some interesting numbers!), I imagine the combination of sabot/piston and that design could result in some serious altitude!

On the subject of spin-stabilisation, how about this:

I don't suppose you'd care to transcribe the referenced bit? The signal-to-noise ratio is a bit low or maybe its just that my codec isn't optimised for the accent. :^)

:-)

Richard P: "D'you think that o-ring was important, mate?" Mike R (or possibly James Fowkes): "It looks like it!" Dave W (RSO): "Oh dear"

How, exactly, does one build a sub-minimum diameter rocket? I always thought that the point of "minimum diameter" rockets was that the rocket's diameter was just large enough to house the motor, and no larger. If the rocket's diameter is smaller than the motor, then I'm having a hard time figuring out how to install the motor....

- Rick "Portable hole, perhaps?" Dickinson

The rocket in question consisted of ~70mm of BT-50, transitioning to a BT-5 airframe, containing the PicoAlt and streamer.

Think boosted dart, but without the booster separating. The rocket did

2300ft on a D12 - apparently it hit 2800ft on the same motor. Verified numbers should be up on the UKRA website once the revamp/overhaul is completed.

Of course a similar design on an AT/Quest/Apogee 18mm D motor (with an 18mm 'booster') would go very, very high!

the link. I have seen his spin stabilized rocket fly several times. There are several video's on the site also. . . ..

Those videos are *very* impressive!

However, I think we (well I am at least :) ) are talking about rockets that are stabilised by spinning them - like a gyroscope - rather than using fins for aerodynamic stability. Same principle that is used in rifled firearms, the Honest John and various other military/research rockets.

Sal 'Mupp' Davis' spin-stabilised 'Mr Peanut' worked very well until the chute deployed early.

Ah, I finally figured it out. He's got an anti-spin stabilized system for use as a video platform. I was looking for info on building fin-less rockets utilizing spin to achieve stability.

Amusing confusion. :^)

Install it just to the rear of the "dart".

Ah, very good. With the proper guidance even I could make it out.

A boosted dart!

After hearing the NPR story abotu Donald Knuth this morning on the way to work, I checked out his web site. He still offers a $2.56 reward for the first person to discover any error, typo, etc. in any of his books. Of course $2.56 is $1.00 hex.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!