Slosh baffles

[dongfang]

Hi,

I tried to do a couple of slightly tilted launches today. Just up against the wind. Disaster every time - the rocket made a sharp turn, and flew more or less horizontally instead.

Hmmmm what happens?

Hmmm isn't this an unstable system? If the mass distribution is off center, then the rocket will turn, and always in the direction that makes it even worse?

I guess I will have to try installing slosh baffles in my next rocket, and see if that improves it.

Regards
Soren

[Spaceman Spiff]

Hi,

I tried to do a couple of slightly tilted launches today. Just up against the wind. Disaster every time - the rocket made a sharp turn, and flew more or less horizontally instead.

Hmmmm what happens?

Hmmm isn't this an unstable system? If the mass distribution is off center, then the rocket will turn, and always in the direction that makes it even worse?

I guess I will have to try installing slosh baffles in my next rocket, and see if that improves it.

Regards
Soren

Your problem will get worse in a few cases:

- Your Fins are too big. This "steers" the tocket into the wind.
- Your fins are too small. The rocket is too unstable and cannot go straight.
- Your rocket is too slow. The CG is too far back because the water weight is inside too long.

You can check the balance of your rocket using the D.D. ROCKETS CP Software 1.2 software uploaded to this topic:
http://www.wra2.org/forum/viewtopic.php?f=3&t=258

The sloshing idea has long been discussed but as far as I recall nobody has proven or disproven the effect.

[xenon]

How strong was the wind? wouldn't the wind if strong enough cause the rocket to steer into the wind like a weathervane points the wind direction?

[dongfang]

Hi,

The wind varied, but it was pretty weak Swiss wind...

Anyway he rocket veered off in different directions. Once at a right angle to the wind, and once down-wind.

Anyway I have thought out a solution: I'm going to shoot the rocket out of one of my potato cannons! (I'm not going for official performance records, just want to have a little fun seeing something disappear into the sky!)

And now I need to make tailfins that will fit in the cannon barrel, a sabot and a release thing that goes through the cannon piston....

Regards
Soren

[Aquafire]

Hi,

The wind varied, but it was pretty weak Swiss wind...

Anyway he rocket veered off in different directions. Once at a right angle to the wind, and once down-wind.

Anyway I have thought out a solution: I'm going to shoot the rocket out of one of my potato cannons! (I'm not going for official performance records, just want to have a little fun seeing something disappear into the sky!)

And now I need to make tailfins that will fit in the cannon barrel, a sabot and a release thing that goes through the cannon piston....

Regards
Soren

Ha ha. That sounds like an anti-tank projectile!

Good fun!