Ye Olde Rocket Forum - View Single Post - EnerJet KE-4 Egg Crate In The Build Queue

I searched the YORF forum for Egg Crate and found at least a couple of members interested in the EnerJet version of this kit (ghrocketman, green dragon) and I’m sure there may be others. I have some files to submit for the Egg Crate as well as a few requests for information & suggestions from YORF forum members concerning the build.

I have two of the PNC-13E/ST-202 Egg Capsules on hand, one of which I’m using to build the EnerJet SR1340 with the large payload section as featured in the Handbook of Model Rocketry 4th Edition (My thanks to SEL for the much needed information he provided to me to assist with that build). A dry fit image of those parts is below waiting for my Semroc order to get here any day now with the EM-9115 engine mounts for 24mm.

I converted the bottom of each of the Egg Capsules to be used on the Semroc LT-125 series tubing instead of the ST-13 tubing these capsules were made to fit into. To accomplish this I cut off the very bottom of the capsule shoulder and left 1” of the plastic shoulder that should have fit inside the ST-13. I also cut 1” of BT-56 to cover this part of the shoulder and I used a piece of wood dowel (bulkhead) to recess up into the shoulder and an Estes BT-56 centering ring that fits nicely from the inside on a little molded ridge and butts up against the 1” of inserted dowel. With a little adhesive the dowel will not be able to pull out of the base because of the centering ring and I can glue a screw eye into the base of the dowel for a more robust recovery attachment than the provided molded eyelet that I removed. I did this since I will also fly a recording altimeter in the capsule when I’m not flying eggs and I don’t want it coming loose. An image of the parts is below and I mention this because if you intend to use ST-13 or BT-56 tubing you can remove the bulkhead & centering ring from the RockSim files below and change the tubing from LT-125 to ST-13 in the files.

I have three RockSim files below. One is for a 29mm mount like the original with the launch lugs mounted as suggested in the instructions. The other two files are for a 29mm mount and a 24mm mount with stand-offs and lugs mounted similar to the Estes 1996 Eggspress/2072 Scrambler instructions. I also provided a .pdf file for those of you that don’t have RockSim so you can have a peek at the design.

Here are the two major questions I have:

Does anyone here have an actual EnerJet Egg Crate fin pattern?
Does anyone here have a scan of the EnerJet Egg Crate decal sheet?

The fin pattern for the EnerJet Egg Crate appears to be different from the Eggspress/Scrambler. I could not read the dimensions because of the scan on Ninfinger to see the fin span measurement in the 72 EnerJet catalog but if you look closely the leading edge has no sweep like the Eggspress/Scrambler and the trailing edge is not clipped. Has anyone else noticed this? It’s also evident in the small picture at the bottom of the page where the kid is putting the parachute into the Egg Crate, as well as in the picture on the rack of rockets on the launch system page.

http://www.ninfinger.org/~sven/rock...2/72ejet10.html

http://www.ninfinger.org/~sven/rock...2/72ejet14.html

What I did was to enlarge the line drawing of the fin from the Egg Crate instructions that are posted on JimZ website until the span was 3” when I printed it out, equal to the span of the Eggspress/Scrambler.

http://www.dars.org/jimz/ke-4.htm

The pattern I estimated is what I used in RockSim and is also included in the .pdf for those of you that don’t have RockSim but would like the estimated pattern. I’d prefer to have a copy of the original pattern/dimensions if anyone here has it but I’m going with this if I’m unable to attain that. A decal scan would be nice as well. I remember when Kevin had Countdown Hobbies there was an original EnerJet Egg Crate decal there but they are rare and I doubt I’ll be able to obtain a scan of one.

Also, (third and final question for this post I promise) what type of paint would you guys recommend for this flexible polyethelene the capsule is made of? Any special paint/primer considerations I should be aware of? I wish I had an original that was molded in black but the Estes versions I have are yellow so I’m going to need to paint them black.

Let me know what you guys think. I’m open for any thoughts or suggestions to assist with the build. Thanks in advance!