Centuri KB-7 Arrow 300
 

This was a really quick build, the Estes Fin Alignment Guide helped make quick work of the 12 fins. A few years ago I bought this as an open kit, it was missing the fin sheets, but Semroc to the rescue! The long ST-8 was a little roughed up on one end, but the ST-7 to ST-8 centering ring for the 3rd stage engine tube is almost an inch long, so it helped take care of the issue. This is one tall an skinny rocket!

Tim could you give the body tube lengths? I looked at the plans on YORP, but Centuri gave no part numbers for the parts.

Huh. I'd always wondered about the fins on that model. I didn't know if they were all the same size or not. Guess now I have my answer.

And yeah, you're right, that's tall skinny, sure enough. Looking forward to seeing the paint.

I built one of those back in the 80's. It flew well, but did have a tendency to weatherc o c k in a slight breeze. The cardboard fins also had a tendency to warp over time. I also noticed the first two stages were the same as the #8 booster. When I built a clone in the 90's, I sued thin basswood instead of cardboard for the fins.

The Centuri Buck Rogers Laser Lance and one other kit went on to use this same fin set.

Here's a link to an earlier thread on the Laser Lance.....see post #19 for a scan of the fin sheet.

http://forums.rocketshoppe.com/show...highlight=Lance


Earl

ST-8 Payload Tube is 8 inches long
ST-8 Main Tube is 15.75 inches long
ST-7 Engine Tubes are 3 inches long
The CR-78 centering ring in my kit measured 13/16" long

The plans on JimZ list all the parts and sizes. http://www.spacemodeling.org/JimZ/cen5037.htm

I have the decals in red but if you select a different paint scheme I can change the color for you.

I considered paper laminated 1/16" balsa. But I went ahead and ordered the Semroc fiber fins. The Semroc fins are pretty rigid, so I have hopes for them.

If you get a good finish on them - ie, get them sealed well - they should not warp and hence should last a long time. OTOH, they will be susceptible to permanent deformation if they, for example, get left in a distorted position for a long time, such as when the rocket is laying on its side resting on the fins. That is, balsa won't bend but fiber will :)

Anyway, I'm glad you're building this. I keep resisting the temptation to start a clone, knowing I already have enough projects going, most of them in extended duration limbo :o

Doug

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Always wanted an Arrow 300 as a kid but never built one. Might have to make a BT60 or BT70 upscale for 24mm power my next project.

Would be neat on an E12 to E12 to E12 full stakk.