direct staging three motors to one

[rocketsonly]

Hey all. I've done some research and found out how direct staging works, but on for one motor to one motor. How does it work if you have a 3 motor set up to a single motor set up? The motor in the 2nd stage won't align with the motors in the 1st stage, will it?
-Matthew

 

[Ryan S.]

you could put them in a line so one lines up with the second stage

for example;

MMM

instead of;

M
M M

you kinda get the idea....if you do it the second way I thinnk you just need to make sure there is a space so the gases can read the second motor

 

[jetra2]

A question back at ya.

1. Are the motors arrainged in a triangular fashion or a parallel fashion?

If they're arrainged in a triangular fashion, you'll probably want a funnel directing the hot gases to the upper motor. If they are aligned in a parallel fashion, you can just run a tube from the central motor to the upper stage motor with no problem.

I need more info to give more info...fair trade, eh?

Jason

 

[Stymye]

one way I've learned of, you could add an internal cone to sorta focus the ejection spatter twords the center of the second stage motor.

 

[sandman]

The TARC team I watched did the three D12-0's in a triangle to a D12-5 and it works great for the first launch but the chute came loose for a DQ. Just one cracked egg.

On their second attempt they used the same technique and the second stage failed to light for a screaming lawn dart.

They used 1/2 sections of BT-50 as channels to direct the blow-by into the second stage. Like a funnel.

The second stage nozzle was badly scorched but failed to ignite.

I let them keep my spare parachute since it was covered in egg!

sandman

 

[rocketsonly]

Oh! I was going to use the triangular method, but it appears to be unreliable.... I'll go with the parallel method and test them this summer!
Thanks,
Matthew

 

[vjp]

Originally posted by sandman
I let them keep my spare parachute since it was covered in egg!

sandman

It's a good idea to seal the eggs inside individual ziploc bags, before placing them in the payload section. That helps to reduce the "icky eggstronaut mess" when there's a mishap.

On a lawn dart, though, it may not make much difference.

 

[sandman]

I think the cone method will work just fine.

Be sure to clean out the nozzle opening slightly (not much) to make sure there is no residual nozzle clay in the upper stage motor.

sandman

 

[loopy]

Originally posted by sandman
I think the cone method will work just fine.

Be sure to clean out the nozzle opening slightly (not much) to make sure there is no residual nozzle clay in the upper stage motor.

sandman

That's the best advice. Good to do that even when direct staging - just to make sure.

Like they say in high school health classes - there is nothing more expensive than regret. Same holds true in rocketry...lol

Loopy

 

[ELBRAZ]

Never had a failure as long as I had a 3 to 4 inch gap between the three motor cluster and the sustainer. (Don't forget the Stine vents!) I usually use wide nozzle sustainers, like D12's or E9's. With the gap you get good dispersion of the burning particles in the booster blow-by. The funnel systems seem to be a waste of time and weight allowance.