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REV 2.4 - Tue Aug 17 11:00:11 2010

Excelsior Rocketry
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SPECS: 12.25" x 4.5" - 1.2 oz
ROCKSIM FILE: MISSING - please submit here
SpaceCAD FILE: MISSING - please submit here
REC'D MOTORS: A8-3, B6-4, C6-5

(Contributed - by Ron Wirth [Who's Who Page] - 09/26/08)

What happens if you take an Estes Mark/Mark II design and turn it into a goony style rocket using a Baby Bertha kit? You get the KRAM from Excelsior Rocketry. As with the other goony retro-bash plansets, the KRAM is not a kit but rather the instructions and decals to turn a Baby Bertha kit into something unique. For this goony, you only need add a BT60 tube coupler and a sheet of balsa to convert a Baby Bertha kit into the KRAM.

This is my fifth goony retro-bash rocket from Excelsior and probably the one I have enjoyed the most in building. The planset has you follow the instructions for the Baby Bertha with the exception of modifying the motor mount assembly and cutting fins from the pattern provided. You are also required to convert the rocket for middle separation by cutting the body tube in half and using a tube coupler to join the sections of rocket. This requires you to modify the nose cone and glue it to the upper body tube.

excelsior_kram_buildingI choose to use Kevlar string anchored to the motor mount for the recover system. Since the rocket is fairly short and splits in the middle, I ran about 12” of the Kevlar string out the lower tube and tied a piece of 18” elastic to that. The other end of the elastic was glued to a standard paper mount that was glued into the upper body tube. The entire build was completed in one evening with the most difficult things being cutting the body tube in half and cutting an unseen portion from the nose cone.

Other than the shorten body shape, it is the paint and the decals that turn your simple kit bash into a goony rocket. This is usually where I would take more time to produce a good looking rocket but my window to launch was very limited so I rushed through the finishing process.

I decided to paper the fins on the rocket as you can see in the pictures. I traced the fins onto a self adhesive label paper. I then apply the paper to the balsa and spread a medium viscosity CA to the edges to hold the paper down and act as filler. The entire rocket was coated twice with grey auto primer. After 4 hours, I sanded the rocket to remove about 90 percent of the primer and then let sit over night.

The recommended paint scheme is to paint the lower body tube black with the fins and upper body tube an orange-red color. I like to have a white base coat prior painting the final colors but didn’t have the time so I tried something different after reading the back of my Rust-Oleum spray paint can. I masked off the section to be painted black and applied the white primer. According to the instructions, you are able to wet sand in 30 minutes and recoat with the same brand of Rust-Oleum paint within an hour. That is exactly what I did. I applied two coats of white primer, wet sanding between coats and then 3 coats of orange all within 2 hours. After letting that dry for 24 hours, I masked the fins and painted the lower section 2 coats of black. The results are ok but not nearly as good when you do it right.

As stated before, the decals add to the Goony feel of the rocket. For the KRAM there are just a few to apply. The decals from Excelsior Rocketry are always top quality and I never have any problem with them if I follow the instructions.

Construction Rating: 5 out of 5

For the first flight of the KRAM I used a B6-4 engine. The rocket went straight up to about 300’ and ejected at near apogee. The parachute deployed and the rocket floated safely to the ground. Considering that that the winds were gusting to 10mph at the time of the launch, I was very satisfied with the first flight.

The KRAM instructions suggest using a streamer for recover but the Excelsior website indicates that you can use either a parachute or streamer. Because of the hard ground where I was launching, I chose to use a small parachute. There is plenty room in the upper tube to hold different sized parachutes or streamers. I tied a small loop half way up the Kevlar string as a place to fasten the swivel of the parachute. You have to make sure it is low enough to pull the parachute out of the upper body tube during ejection.

Flight Rating: 5 out of 5

The KRAM is another cool classic rocket made goony by Excelsior. If you are into goony rockets, then the KRAM is a fine addition. Even if you are looking for a 3FNC rocket, the KRAM is just different enough that you will not be sorry you built it. It is the perfect rocket to see what is possible when you start to kit-bash. I look forward building other Excelsior goony rockets and hope to continue to see new ones become available.

PROs: Middle separation creates a cool rocket, It’s Goony!
CONs: Priced the same as other Goony plansets but you only receive a small sheet of decals.
Overall Rating: 5 out of 5

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