staged cluster question

[CATO]

On the drawing board for the winter is a fairly large two stager that would use 3 BP motors staged to a single BP motor. However, you are obviously supposed to block the top of the cluster motors with wadding or like to prevent them from firing backwards. I imagine that this risk would be even more prominent with, booster motors, as the ejection cap could (potentially) prevent this form of CATO. However, wouldn't this procedure block and/or cool the gasses and particles from the motor, preventing staging? How can you achieve a safe but reliable BP cluster to single staging

 

[outasight13]

well, first of all, it depends which cluster configuration you want, a triangle 3 motor cluster staging to a single motor cant work, because the single motor would have to be off-center to line up with one of the bottom motors. if you are talking about a 3 motor in-line cluster like this: ( )( )( ), then you put the single motor in the middle and youre lined up.
you could use 3 booster motors, ie: 3 B6-0's, and pack the two outer ones with wadding. this would let the middle motor light, but the two outer motors wouldnt do much if any damage.
if you are talking about D or E staging, then use a two plugged motors on the outside and a booster motor in the middle.

 

[Micromeister]

Outasight13:
First..Never say Never.
Second triangular 3 motor clusters work just fine as long as you direct the burnthough gas and particles. as with all gap staging they must be vented but the configuration works just fine. Ask just about any of the TRAC teams from the past couple years. Personally I've used this method many times. over the years. You are correct 3 motor inlines are easier to do using direct "taped" staging, but it isn't the only way to accomplish the intended goal

CATO:
Before I go into a long explaination of how to consturct a staging cone and all that. can we get a little more information on exactly your trying to stage. what Size booster body (exterior) tube are you thinking of? same for the sustainer section, containing the single motor. and as Outasight mentions motor sizes for both D's for the booster? what about the sustainer?
Have you considered simple types of electronic or electric upper stage ignition, simplest is a mercury switch and 9volt but you need room for these things. Staging timers and/or other electronic upper stage ignition don't have to be expensive if you are a little handy with a soldering iron
Hope this helps a bit.

 

[Fore Check]

A simple technique (that may not fit with what you are attempting) would just be another wrinkle in the parallel staging.

Put a central booster motor in the central airframe (directly in-line with your sustainer motor above) and use "strap-on" boosters - external motor tubes attached to the booster frame on the outside.

Similar to this pucture below. The strap ons are attached to the booster and fall away when the sustainer ignites and keeps going.

 

[JBeau]

Originally posted by Fore Check
A simple technique (that may not fit with what you are attempting) would just be another wrinkle in the parallel staging.

Put a central booster motor in the central airframe (directly in-line with your sustainer motor above) and use "strap-on" boosters - external motor tubes attached to the booster frame on the outside.

Similar to this pucture below. The strap ons are attached to the booster and fall away when the sustainer ignites and keeps going.

The Estes Renegade, my current nightmare of too many mods in one build, was perfect for this type of clustering.

Here's the business end clip of a Renegade Extreme reviewed on rocket reviews...

...and you can see the side pods with the large engines added. Mine only has a single engine in the middle, too, so it's like the configuration you'r suggesting.

 

[CATO]

The current design is BT70 with a BT70-BT80 transition on the booster. Booster has 3x 24mm mounts, and the sustainer has a single 24mm mount extended for E motors. The concept of using plugged booster motors won't work, as Estes dosen't sell a E 9-0, and D ?-P motors only come in D 11-Ps, which have different thrust from the D 12-0s the booster would use.

 

[outasight13]

Estes sells E9-P motors........
also where did you find a BT-70 to BT-80 transition, ive never seen one.

 

[CATO]

Originally posted by outasight13
Estes sells E9-P motors........
also where did you find a BT-70 to BT-80 transition, ive never seen one.

I know they sell E 9-P motors, but they don't sell E 9-0 motors. ALso, Bill Stine's book has a formula for making paper transisions

 

[ben]

Originally posted by outasight13
also where did you find a BT-70 to BT-80 transition, ive never seen one.

one word well name

Sandman that's all I have to say

thanx, Ben