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-   -   Sprite question (http://www.oldrocketforum.com/showthread.php?t=11331)

paul.nortness 07-08-2012 07:30 PM

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?

mwtoelle 07-08-2012 08:36 PM

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.

Carl@Semroc 07-08-2012 09:24 PM

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.

Crimsonvelvetflame 05-25-2019 02:35 AM

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.

ghrocketman 05-25-2019 03:17 AM

The original posts to this thread were seven YEARS ago.
Not sure it is still valid for the OP... :rolleyes:

astronwolf 05-25-2019 05:48 AM

Not sure the OP is even valid. This was his only thread.

BARGeezer 05-25-2019 06:15 AM

3 Attachment(s)
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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