Scratch e-Cluster Original Design / Scratch Built

Scratch - e-Cluster {Scratch}

Contributed by Zak Orion

Manufacturer: Scratch
Style: Cluster, Contest

e-Cluster

I designed this rocket with 2 purposes in mind. One was to build a mid power cluster that was capable of E and F engines without having it go out of sight(smaller launch fields). And number 2 was to build it as strong as I could using easy to find materials(namely cardboard tube and wood fins). Here is the design I came up with:

I decided on a LOC 54MM motor mount tube(thick walls) and nosecone. The fins are 1/8th inch Aircraft Plywood and use TTW construction. The MMT's are Estes BT-50 with 1/8th inch aircraft ply centering rings(extra from fins). I used 5 minute Epoxy throughout the rocket. At first I was going to set it up for testing timers and possibly dual deployment but I wanted to test it before I cut the tube and made a payload bay. But after the first day of flying it I couldn't bring myself to modifying it. Here is a pic of the finished product:

RockSim Pic

Rocket Pic

LaunchThe first flight, I tried putting a 12 inch chute on the rocket so it would drop quickly, unfortunately it dropped too quick and took a hard hit on the ground. When I retrieved the rocket I didn't find any damage so I loaded it up again(this time using a 18 inch chute) and flew it again. On its first launch it had a curious roll which I found out that only 2 of the 3 engines lit. But on the 2nd flight all 3 E9's lit and it went straight up, barely any side to side movement and very little spin. Here is a launch pic:

I have launched this rocket 9 times now in various weather conditions(everywhere inbetween 3 mph winds and 20 mph winds) and it always flys the same, very straight and very little spin, and is the best flyer I have. As for its toughness, it fell fast on its first flight, fell with no plastic slug as a chute on its 6th flight and got one of its fins run over by my car and the only damage it sustained was losing a launch lug. So far all of its launches has been on E9's but as soon as I can get some ignitors other then copperheads I will be flying this rocket on some F's that I have in my engine box. I also put a rocksim file of this rocket on EMRR. It is a simple design but a very nice flyer that I have been reliably dropping in a 20 acre field.

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