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Enerjet Egg Crate - a couple of parts/advice needed

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Tramper Al

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Hi,

I am putting parts together to build a nice Enerjet Egg Crate clone, and a couple of things elude me.

First, I need an engine mount to put the 29mm motor tube into the #13 body tube. That isn't much of a difference in diameter (so not rings), and the original plans called for a centering tube that looks to be an inch or two long. The nearest thing I have found is in the erockets/Semroc parts list, a #13 coupler. Would that likely work, or is there a real or better 29mm/#13 centering tube out there?

Second, the instructions (though not catalog photo) shows a nice egg shaped decal for each fin, with "Egg Crate" on it. Anyone have an idea where I could find a scan or other file that I can use to print up a decal? My first drawing attempts are not so great. Thanks.

For the egg capsule, I am using the Estes TARC small parts version, which I will try to cleverly paint a glossy black. I have a scan of the fin template, #13 tubes are widely available, and I have various Enerjet decal scans to use on the body tube. I'll also try to track down a vintage parachute or two.

Thanks in advance.
 
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astronwolf

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K'Tesh

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Tramper,

If you have any Estes PSII kits lying around, you can pilfer them for the little green spacer rings (PN 031360) that come with them... They fit over the 29mm motor tube, and you might have to peel them to fit inside the BT-56 you'll need for the nosecone.
 

Tramper Al

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Tramper,

If you have any Estes PSII kits lying around, you can pilfer them for the little green spacer rings (PN 031360) that come with them... They fit over the 29mm motor tube, and you might have to peel them to fit inside the BT-56 you'll need for the nosecone.
Thanks, I'll give this a try too.
 

caveduck

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For the spacer tube there are two cases depending on what you are using for the main body tube.

Authentic main body: The original Enerjet Egg Crate used the .045 wall LT-125 (Semroc exact equivalent #125 tube) with a quoted ID of 1.25" for the main body; assuming the authentic Semroc #115 MMT with OD 1.22" that leaves only 0.030" to take up with the centering spacer. That implies a .015" (or a bit less) wall thickness spacer tube (thinner than Centuri's .022 regular tubes!). That could be done with a paper or cardstock buildup on the MMT. But the modern Estes egg capsule will need some serious sanding on the shoulder.

ST-13 main body: The Enerjet heavy-wall MMT LT-115/LBT-115 tube (Semroc equivalent #115) has OD=1.22" and a .040 wall. That leaves 0.080 clearance to a modern ST-13 ID of 1.30". So for the ST-13 option you are going to need about a .040" wall spacer. If you used a split piece of MMT for the spacer tube you're at an almost zero clearance fit in ST-13. The Semroc HTC-13 coupler may well work but you'd want to check the ID; it's not given on the e-rockets site. But I think there's little doubt it will be fairly close and you can make it work with either a bit of Dremel sanding inside the coupler, or a buildup on the MMT.
 
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