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motors required for TARC

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rocketsonly

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Hey all. I was just wondering if anyone had any idea of what motor is required to shoot a 4 foot long BT-70 rocket w/ 2 eggs? Would a double staged 'E9' do the job? It needs to go to 1400ft.
-Matthew
 

loopy

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Apogee Components sells a software program called Rocsim that allows you to design a rocket and test it with different motor combinations to see what motor combinations and rocket designs will get you to what altitude and whether or not it's stable. They have a free trial version of the program available at their website. If you're interested in TARC, I suggest studying other egg lofter designs to see what has worked. I've seen clustered boosters staging to single engine sustainers work quite well. I've also seen composite boosters with electronically staged sustainers that have also worked quite well. Do some research, plug your design into rocsim and see what happens! Good luck!

Loopy
 

vjp

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Also, keep in mind that although Estes announced there would be an E9-0 booster motor, it was never produced (with good reason - not enough max thrust to loft most two-stage configurations).

The most popular TARC configuration I've seen is a 3X cluster of D12-0's in the booster, with an E9-6 in the sustainer.

Ditto on the RockSim recommendations too. Download the free demo and play with it.
 

shockwaveriderz

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vjp: thats what I'm seeing also: 3 d12-0 cluster to an e9-x.

since the d12-0 have approx 17Ns each that would be 17x3= 51 NS total.... so what we also could use might be a 50-60 NS composite first stage with electronic timing to an e9-x on the 2nd stage.....

suitable engines might include :
F21-4W
F20-4

Use electronic staging to ignite the upper stage and allow the 4 sec delay to kick out a small streamer or chute for the booster stage .....
 

shockwaveriderz

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rockets: ONLY you can decide if you think using electronic timer staging for my suggestion is less complex and has a higher probability of working verus igniting a 3 engine cluster of d12-0......

Obviously you have to take into consideration the cost of the lectronic timer ..take a look at the perfectflite timers at www.perfectflite.com.....

there are other timers......

do a search here in TRF to get a listing.....
 

daveyfire

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thank u, next
Originally posted by shockwaveriderz
rockets: ONLY you can decide if you think using electronic timer staging for my suggestion is less complex and has a higher probability of working verus igniting a 3 engine cluster of d12-0......
That's what we did. I trust a G-Wiz more than I trust my clustering skills... it's fired every time, the only reasons we didn't stage was due to my own stupidity (always LABEL your connections! :p )...
 

rocketsonly

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Now, how does the timer know when to start? Is it possible to program it to ignite right when the 1st stage is done?
-Matthew
 

loopy

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The timer senses lift off with a G switch. The pressure from launching on the booster turns it on. You set the timer to fire a specific time from the lift off detect. Basically, set it to fire right after the burn time for the booster motors is gone.

Loopy
 
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