Dual Deployment Harness Arrangement

[chrocket]

How do you arrange harnesses for dual deployment for drogue deployment.
Shall the payload section containig the main chute be above (A) or below (B) the booster?

With A, I see the risk to "shoot" the nosecone into the booster section, when main deploys.
With B main could get tangled with the booster section?

 

[Banzai88]

Either one will work. Gravity does the work for you.

 

[FredA]

Depends on harness length.
I tend to go with the NC always above.
Then put lots of harness on the booster so the NC can't reach the booster.
But odds are against the NC will be aimed at the booster.

 

[Bat-mite]

I go with A, but have done both. It would be easier for the longer harness in B to get wrapped around the fin can than the NC (A).

 

[chrocket]

Thanks very much for the good hints and explanation.
Will post a pic of next launch in spring.

 

[Nathan]

A is the way it's usually done because you're less likely to have an entanglement problem when the main deploys.

And I'm not aware of any reason not to attach the drogue directly to the eyebolt on the bottom of the payload section. It is often done the way you have drawn it with the drogue attached some distance down the harness away from the payload section but I don't know why. Maybe someone can explain the thinking behind that. It seems to me that it just unnecessarily reduces the separation between the payload section and the booster.

 

[OKTurbo]

I go with A. Mostly because I want the drogue chute out of the tube quickly. When the rocket separates you want it pulling that chute out first...not a bunch of harness that could slow the separation and risk the chute getting stuck.

 

[crossfire]

Vote for A or drogue less

 

[UhClem]

B is my usual choice.

 

[cerving]

A, better chance of the drogue chute coming out. BTW, your drawing looks like a single-deploy rocket... make sure the shock cord is long enough so that the NC/payload bay can't hit the booster, and ditto for the main's shock cord. That's another good reason for going with A over B.

 

[H. Craig Miller]

Related discussion: Rocket hitting nose cone...

 

[Nytrunner]

Great discussion

B is my usual choice.

What are the factors behind your choice of B? I mainly hear arguments in favor of A so I'm interested in the opposite

 

[UhClem]

What are the factors behind your choice of B?

I usually build using an anti-zipper configuration so connecting the drogue at the front of the fin section provides for the best apogee deployment. As shown in the linked video. (See also the Ted Cochran R&D report.)

I really like getting a parachute deployed at apogee as that ensures that the descent will be controlled even if the main gets fouled. Or doesn't come out at all.