Sunday, March 6, 2011

Corkscrew 2 Build Part 1 Parts

Mr. Levison's Cork Screw was designed for 18mm engines, built around a BT-20 mainframe with a 3" ring fin on the bottom.

I wanted to fly this one at the local schoolyard soccer field so I'm downsizing it for 13mm engines with a BT-5 main tube and 2 1/2" ring fin.

After building it too LONG with the clay weight in the nose cone, I found the Corkscrew to be overstable! You could see it spin on the way up, but didn't "cone" or spiral as much as I wanted to see.
The build pictures will show the first version, longer with the nose weight. The revised sizes and changes are shown below in italic type.

Parts:
PNC-5 Estes plastic Nose Cone, Elliptical 2 1/8" long
Or, Semroc BNC-5AW is very close to the shape shown here
Or, Use whatever BNC-5 style cone you have handy
I used a plastic cone and in the first build I added nose weight to be sure of stability. Nose weight was removed after I found the rocket to be too stable - not enough "coning"
.40 oz. Clay Nose Weight
(it's in the picture but not used in the revised model)
BT-5 Mainframe 12" long
(The first version body tube was 16" long, 12" is what I ended up using)
BT-70 Ring Fin 1" long
2 Launch Lugs 1/8" X 2" long
(The original had two lugs that were 1/8" x 1 1/4" long, I now feel longer lugs are needed)
TB-5 Engine Block 3/16" long
18" Kevlar
24" Elastic Shock Cord
Crepe Paper Streamer 1 3/4" wide x 18" long

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