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Elapid

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here's a trio of pics of my most recent kitbash...
i had the booster sitting around for awhile now...
8-motor cluster -> 24mm sustainer





 

KarlD

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Can you post a picture of the business end of the booser? trying to get a handle on what you are doing there.
 

Elapid

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with all the different burn times of the cluster motors, it would be much simpler to use the two longest-burning motors to control the flight events.

one 24mm will light the sustainer (via a conduit that is not installed in the photos) and the other will deploy the booster's chute which is stowed in the BT60 internal tube shown in the photo.
 

Elapid

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it WORKED!

i used a sort of flashpan ignition to light the booster, 6 of the 8 motors lit, the rocket was not fully stable so it was wandering around the sky a bit... the sustainer lit while horizontal and the E9 motor took it off into the distance... never to be seen again.

it was still spectacular!

the booster deployed the recovery device, but the shock cord burned through...

another ounce of noseweight and it's gonna fly great!
if the other motors (C6) had lit, maybe it would have done better also.

i learned a LOT from this flight, so i consider it a success in part.
 

Elapid

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the motors responsible for staging and deployment were both Estes E class motors.

the sustainer motor had the nozzle end filled with 4f BP then covered with tape to keep it full.

that's the same way the cluster was ignited, filled the motor's nozzles with 4f, then covered with a piece of tape, then taped an igniter to it covered by another piece fo tape.

the simulation showed that the sustainer required 7 oz of weight for it to be stable.

next time i'll make sure that's how much weight gets added
:eek:

this was my biggest cluster to date!
:D
 

Elapid

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was due to this model, seeing as how it was a success the first time...in a way...
 

Elapid

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i flew the FB^2 today!
it boosted perfectly this time!, sustainer lit and just kept going....wow!
i used a single E9 for the sustainer... i recovered the sustainer's nosecone, but the sustainer was not found. each part had its own parachute, so i may be able to find it in the daylight...

here's the pic taken just after separation of the booster
:D
 

mike_bar

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Originally posted by Elapid
i flew the FB^2 today!
it boosted perfectly this time!, sustainer lit and just kept going....wow! (snip)
Rob,
That is a fine looking two-stage Fat Boy. I just picked up my second kit from Michael's Craft Store. (I love their 40 percent off coupons.) I'm going to work on a two stager as well. I'm thinking of E9's in mine, but maybe a cluster of D's.... I have to sim it first.
Mike
 

powderburner

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Elapid,
Out of all those booster motors, how do you make sure the two key motors ignite?
(You said you got 6 of 8 to ignite using a flashpan)
Your booster apparently uses one 24mm MMT to ignite the upper stage and the other 24mm MMT to deploy a 'chute. Cool design. What if one (or both) of THOSE motors do not ignite? Seems like you have a pretty good pucker-factor on this design--
Do you do anything special to make sure the 24mms do get started?
 

mike_bar

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Originally posted by powderburner
(You said you got 6 of 8 to ignite using a flashpan)
Your booster apparently uses one 24mm MMT to ignite the upper stage and the other 24mm MMT to deploy a 'chute. Cool design.
I was thinking of a simular booster design, but I thought of using clustered igniters instead of a flashpan.
 

mike_bar

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Does anyone know which typeface approximates the Estes Fat Boy font?

I found font, Bauhaus 93, on my Windows XP machine.
It looks pretty good. See attached file.
 

Elapid

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have relatively HUGE nozzle throats so they hold more 4F than the others and are more likely to ignite.
Since the 24mm motors (E9) have a 3-second burn time, it would be difficult to try to get the timing on any of the other motors (As and Cs) to coincide with the typical flight events.

if BOTH the two big motors don't ignite, it might not make it off the launch pad, though i haven't checked.


Originally posted by powderburner
Elapid,
Out of all those booster motors, how do you make sure the two key motors ignite?
(You said you got 6 of 8 to ignite using a flashpan)
Your booster apparently uses one 24mm MMT to ignite the upper stage and the other 24mm MMT to deploy a 'chute. Cool design. What if one (or both) of THOSE motors do not ignite? Seems like you have a pretty good pucker-factor on this design--
Do you do anything special to make sure the 24mms do get started?
 

marvSRG

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Awesome project. I love me some flashpan clusters (hence the avatar). Just out of curiosity, how did you use E9's as the boosters and how did you ignite the upper stage?

I heard the E9-0 was a myth...is it not? Or did you just core out the ejection and delay on the motor? And for the staging, I saw that you filled the nozzle of the sustainer with BP, but how did you light it? Just standard gap staging?

Awesome job man, if you do it again, send more launch pics!
 

Elapid

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The E9-P has neither a delay element, nor an ejection charge, just a thick clay plug that gets removed.

it uses standard gap staging, but since the motors aren't aligned, i thought the 4F would assure ignition of the sustainer, so i filled it with 4F and covered it with tape also.

so far, so good!

I'll be flying it out at Mudrock 2005
:D
 

richalex2010

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You know, that rocket really stinks:rolleyes: . Actually, I'm doing a cluster Fat Boy too, though not staged (for now...). I might transform mine (My current one) into the sustainer, since it'll have a 24mm centran motor, and 4 18mm outboards (still inside the tube), using a Fliskits EMK5-124-418-8 motor mount. I'll plug the 18mm tube so that the motors can eject while the 24mm motor is still burning (Like a central E6, and 4 outboard C6 motors). Post more pictures! Please!
 

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