short tube dual deplyment?

[rocketkyle]

Does anyone know how I could dual deploy a rocket with a very short body tube (V2), with the main chute coming out the same end as the drouge?

Thanks,
Kyle

 

[AlexM]

The Defy Gravity Tether [Link] should work.

 

[brianc]

Check out Flight of the Bee Two Revisited by Chuck Nozicka in the Jan/Feb 2004
Sport Rocketry. He has a great drawing of his 1/3 scale V2 showing the dual deployment
details...

He essentially installed a tube in the NC that held the main and a piston altimeter bay. Drogue
was in the BT.

 

[rocketkyle]

Thank you both. I'll check out the Sport Rocketry article.

 

[Mad Rocketeer]

If the body tube is wide enough, you could put the main in a separate tube inside the main one, letting the engine ejection charge push out the drouge, then using an altimeter to shoot the main out of its separate tube. Probably best to cap the tube within a tube with something so the main doesn't get shoved down by the engine charge and so the main doesn't get caught by the air stream before it's time.

 

[dbarrym]

Originally posted by Mad Rocketeer
If the body tube is wide enough, you could put the main in a separate tube inside the main one, letting the engine ejection charge push out the drouge, then using an altimeter to shoot the main out of its separate tube. Probably best to cap the tube within a tube with something so the main doesn't get shoved down by the engine charge and so the main doesn't get caught by the air stream before it's time.

Andy Woerner of Polecat Aerospace is doing something like this with his short/fat rockets...basically he puts the drogue in the outer "ring" and puts the main in the center tube. He just uses wide masking tape to cap off the center tube. I think he calls it his "mortar" system. I am using this setup on the 10" V-2 that I am building now.

I'd think you would need to make the main shock cord long enough so that the chute is extended past the drogue and nose so the main shrouds don't get tangled up. But ask Andy for specific details.

Barry

 

[jraice]

Andy's method does work (he has done it several times) but I have always wondered what keeps the drogue/nose from tangling the main chute as it inflates and passes right by...?

 

[rocketkyle]

Thanks everyone, I had thought of this, but I'm only looking at doing it in 4" tubes. I could probably make it happen, but it would be mighty cramped...I might try it.

Thanks again,
Kyle.

 

[Mad Rocketeer]

Originally posted by jraice
Andy's method does work (he has done it several times) but I have always wondered what keeps the drogue/nose from tangling the main chute as it inflates and passes right by...?

You could use one of those slider thingies on the shroud lines to help the main chute get out past the other laundry before it has time to open much. I'd want to do something about the sticky underside of the tape if I used that. Maybe some paper or else more tape, reversed. Probably, I'd just put printer paper over the tube and tape it around the edge. I'd think a 2" tube within a 4" tube would leave plenty of space for both purposes. A 2" tube can hold a lot of laundry, and 3/4 of the cross-sectional area would remain in the rest of the 4" tube (equivalent to a 3.464" tube, if such existed).

 

[rocketkyle]

Thanks I'll try it. I have some 2" mailing tubes.

-Kyle.

 

[jraice]

I would do it like this, you have a really long motor tube, it could even go into the noe cone (54mm would be realistic, if it is smaller I would mount it in the 2" tube). The electronics could be mounted just above the motor (probably would want a couple of inches above the motor and with some form of really strong bulkplate just incase the motor has a failure). Drogue goes around the motor tube, main is in the motor tube, I am pretty sure this is how Andy's design works. I am not actually sure if the drogue or the main goes in the middle "motor tube" but I am 99% sure his extra tube is centered, not off to the side.

 

[karatekicker271]

Originally posted by jraice
I have always wondered what keeps the drogue/nose from tangling the main chute as it inflates and passes right by...?

Andy is a magic man... didn't you know that?
Haha
I have seen this technique tried with great sucess. Should work of executed properly.