Estes Screamin Mimi to Der Red Max

Manufacturer:

Scratch

Contributed by James Gartrell

Brief:

Upsized motor mount to hold Estes E-9. Substituted fin design, paint scheme and Tango Papa decals for Der Red Max. Omitted super sonic whistles and related fins, although I seriously considered including them to make a "Der Screamin' Red Max." Length of the rocket is 26 inches, rather than 25.5 inches for the Screamin' Mimi. Also, replaced shock cord with a Kevlar/elastic combination. Installed screw eye with JB-Weld into the hole in the nose cone base. Used basswood for fins. Modified an old Estes E-motor engine hook to fit the newer E-9's. Basically, the only thing I used from the kit was the main body tube, nose cone, centering rings, engine hook retainer, and engine block, but I got it at a 1/2 price sale at Hobby Lobby for $5.50.

Modifications:
The motor mount was installed with yellow glue, then JB-Weld was coated around the outside of the upper and lower centering rings to harden them and then filleted - this may be overkill, but I believe I can send it up with an F-21 without any problems. A screw eye was inserted into the center of a piece of cellophane tape, then a glob of JB-Weld was inserted into the hole in the base of the nose cone, then the screw eye was inserted into that with the cellophane tape holding it in place and keeping the JB-weld from seeping out, and then inserted the nose cone into the body tube to allow the JB-Weld to seep down to the base of the nose cone - makes a much stronger shock cord attachment point than the standard plastic hook on the base of the cone. The cellophane tape is easily removed after the JB-Weld dries. Also, I installed 1/8-ounce of clay into the nose cone before installing the screw eye, just in case I decide to fly that F-motor. As usual, Estes' standard shock cord is too short and must be frequently replaced. To avoid the issue, I installed the Kevlar cord into the shock cord mount so that it extended outside the body tube, then formed a loop that placed the center at the top edge of the body tube. I attached the elastic shock cord to that and then to the nose cone. Also, I soak in a little CA into the top lip of the body tube for improved strength there. The loop with the CA seems to minimize the potential for "zippering" when that motor delay isn't just right. I've used this method on rockets that I've launched many, many times without a problem. I installed the fins using yellow glue, then created JB-Weld fillets. Use a plastic bag over your finger to smooth out the JB-Weld to make some really nice fillets. Here again, the JB-Weld fillets are probably overkill, but I feel better about them when that F-motor kicks in. I had to hammer out the end of the old Estes E-engine hook and then reform it to fit the new Estes E-engine - pretty easy with a vice and hammer, just go slowly so you don't break it.

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