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Old 07-08-2012, 07:30 PM
paul.nortness's Avatar
paul.nortness paul.nortness is offline
Junior Rocketeer
Join Date: Apr 2011
Posts: 15
Default Sprite question

Just got a Sprite and I am sitting down to build it. But something doesn't quite look right to me.

It looks like it has a standard engine hook instead of a mini hook. I test fit a motor with the sleeve and the hook is way too long. What gives?
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Old 07-08-2012, 08:36 PM
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mwtoelle mwtoelle is offline
Flying since 1977
Join Date: Oct 2010
Location: Middle TN
Posts: 438

You have the correct size motor hook for the Sprite. The hook is supposed to the motor in the rocket so that it does not get ejected from the rocket. However, the casing is supposed to slide back during ejection. Otherwise, the Sprite would lawn dart if built with the shorter EH-3 motor hook. The older Scout (Estes K-1, Semroc KV-4) works on the same principle, but uses standard motors instead of the Short motors.
'Til next time,

Mike Toelle

NAR 31692 L1

SAM 0373
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Old 07-08-2012, 09:24 PM
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Carl@Semroc Carl@Semroc is offline
Junior ??? Rocketeer
Join Date: Mar 2005
Location: Knightdale, NC
Posts: 1,470

Sorry for the delay. I have had the flu since last Monday. Chills and fever have made me lazy. I should not have to sleep anymore during July. Some vacation.

I will answer the Sprite questions in the open forum. Thanks for your patience.
Carl McLawhorn
NAR#4717 L2
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Old 05-25-2019, 02:35 AM
Crimsonvelvetflame Crimsonvelvetflame is offline
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Join Date: May 2019
Posts: 2

paul.nortness, I have an Estes Astron Scout from the 1970's and the engine retaining clip is longer than a standard engine. This is to shift the engine casing rearward ( center of gravity ) C/G at ejection, or deployment, for a tumbling lightweight recovery, without ejecting the engine casing. The clip should hang out some, but remain hidden inside the tube fin assembly. If your kit was not supplied with a BT-5, but a BT-20? The Astron Sprite was originally designed to fly with Estes 18mm Short Engine Series Motors no longer in production, they were an experimental rocket motor, like a thicker walled Estes Mini Series Motors. Install a Mini Engine Adapter 5/20, 13mm/18mm to launch. I prefer ejecting the motor mount, attached to the nose cone, with lightweight stranded Kevlar 3 feet long, so everything is recovered, it's lighter in weight, just add nose weight, if necessary and wadding. Hope this helps.
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Old 05-25-2019, 03:17 AM
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ghrocketman ghrocketman is offline
Join Date: Jul 2005
Location: Nunya Bizznuss, Michigan
Posts: 12,591

The original posts to this thread were seven YEARS ago.
Not sure it is still valid for the OP...
When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL
, if you have to ask what is "NORMAL" , you probably aren't !

Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
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Old 05-25-2019, 05:48 AM
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astronwolf astronwolf is offline
Master Modeler
Join Date: Mar 2013
Location: Northeast Ohio
Posts: 945

Not sure the OP is even valid. This was his only thread.
-Wolfram v. Kiparski
NAR 28643 - TRA 15520
Ready for first flight: N20 Demon
Paintshop: Long Tom
Building: Semroc MX-774, a few competition birds, Honest Ivan
In the holding pen: Ace Mongrel
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Old 05-25-2019, 06:15 AM
BARGeezer BARGeezer is offline
Avid Builder
Join Date: Nov 2017
Posts: 576

Funny, I was just about to paint a Semroc Sprite after shooting primer and sanding. Had one as a kid some 50 odd years ago. Might have been a free kit from Estes.
The OP may be long gone but for others who are wondering, the Sprite is a tumble recovery model. At ejection the casing moves back shifting the CG rearward. At the same time the ejection gases are ported through two holes in the forward body. This results in a tumbling, rather than a ballistic descent. And that's why the engine hook is longer than the casing. Cheers.
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Last edited by BARGeezer : 05-25-2019 at 06:58 AM.
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