staging with stuffer tubes....

Hi everyone...

I'm getting ready to do an upscale of the Estes EchoStar. I'm only going to be takeing up a little bit as I want to fly it on Estes motors. Something else I am going to try and do is make this 2 stage rocket a 3 stager. My only concern is that the sustainer will have a stuffer tube around 13" long. Has anyone had any exsperance with this long of a stuffer tube? Is it possible? I have heard of going up to 10 and 11".

I've attached a pic for anyone that hasn't seen this rocket yet. My brother-in-law has the kit. and I'm gong to scratch built one a little bigger. The origanal is based on a BT-55 main body tube size and 29.5" long. I'm looking to take it to a BT-60, possibly a BT-70 if I can find some tubbing. I did the upscale on Rock-Sim in BT-80 but that was a bit much for Estes Motors and no electronics.

Our HPR flying season is over here in Indiana, so I have to build something to fly in the local small open fields.

Originally posted by Electrode
...I've attached a pic...

Click to expand...

Tim, no pic showed up, please try and repost.

Thanx

my fault I forgot to attach it... here it is...

I'm not sure what the problem with the stuffer tube would be. It might add a bit of weight, you gotta make sure there is room for your recovery stuff, but in general the more stuffer the better from an ejection pressure standpoint.

the question I have with the stuffer tube, is would it light a staged motor 13" up the tube... The rocket isn't a problem... I'm think'n of just attach'n two motors tommarrow with the stuffer tube to see if it works on the work bench out side...

Geesh I'm slow sometimes...it didn't strike me that the staged motoer is so far separated from the booster. Testing it sounds like the best idea to me. Just curious...is there a vent(s) between the booster engine and the staged engine to relieve the pressure?

apsolutly on the vent's... it is a must with the estes stages, as far as I'm concerened... you have to imagain that it's hot particals that fly up out of the booster motor that light the sustainer motors, along with this is hot gas, and it will defently push the motors apart before the ignition if given the chance.

I was hoping someone had some advice on the subject, I haven't really built a model rocket in some time... too bussy work'n on my bigger stuff. But this one caught my eye and the challenge of makeing a 3rd stage that far away, work and all.. really intreaged me....

I'll post more on the subject after my testing...

Ok, I just couldn't wait... I got a 24mm tube, 12" long.. longest I had... Taped a B6-0 to one end.. 1/2 sticking out.. then taped a D12-5 to the other end, 3/4 stick'n out.. taped the whole thing to a 1/4" launch rod, stuck it in the ground nosels sticking skyward.

And ignited the B6-0... it was awsome.. it burned.. lit the D12 and seperated from the body tube..

The only problem was that I had the D12 taped on with masking tape to the body tube, and so as the D12 Burned... it burned up the motor tube.. oh well.. but it lit.. yes it lit.. I'm on my way to the hobby shop to pick up materials.. I can't wait to get started...

I think I might do another static test, with a longer tube and couplers that seperate to make sure it all works with out burning up.. maybe I'll take a couple of photos and post them as well....


More later...