Rocket Dynamic Systems - North Star

Contributed by John Coker

Manufacturer: Rocket Dynamic Systems

(Contributed - by John Coker) 

Note: For more North Star pictures, visit John's site.

[Rocket Pic]I have been wanting to build a multi-stage rocket for a while since I haven't even built an Estes Comanche. There are several kits available, several from Public Missiles Limited and another I found from Rocket Dyne Systems

After the fragility of the phenolic tubing was so drastically demonstrated with my Aurora and Bull Dog kits, I wanted to stay away from P.M.L. Also, Mike Gillette of Rocket Dyne Systems was so helpful and confident about his rockets that I decided to go ahead and buy his North Star 2-stage kit. 

I was hurrying to finish this rocket in times for Balls '98 (August 1st) and so didn't finish the painting. Fiberglassing the entire body turned out to be more work than I expected and I didn't finish it as completely as my other rockets. It's unoffical name is The Unfinished Rocket. 

The Northstar maiden flight was at Balls 98. Unfortunately, the motor flew through the booster, battered the sustainer and proceeded to skywrite through its 4.5 second burn. The motor flying by itself got the loudest cheers at the launch! (The hose clamp was not enough to hold the single-use K500 in place.) The rocket is repairable, but is just sitting in my garage at the moment. 

[Rocket Pic]You can see that the payload section and nose are nicely finished and painted, but the booster and main sustainer airframe of The Unfinished Rocket are still raw. 

The Northstar was assembled with the two motors, a K500 for the booster and a K250 for the sustainer, the two igniters wires run and the timer was enabled and the hatch screwed on. Everything ready to go and ship-shape, or so I thought. 

I didn't get a picture of the launch or the skywriting, unfortunately, but here is the sad rocket after the non-flight. The booster (red) is still on the left launch pad and the sustainer (green, red and black) is laying to the right. The booster parachute is stretched out to the left.[Rocket Pic]

At the moment, I don't want to look at this rocket, but hopefully I will get up the energy to repair it, or at least cut the unfired upper stage motor out of the rocket! 

The Kit

The kit is made with soft Kraft paper tubing, which is easy to work with if you are careful, but needs fiberglassing to be strong enough. Also, the paper has a soft outer wrapping which starts coming off as soon as you try to sand the tubes. I ended up using 4" carbon fiber reinforcement along the fin roots and then fiberglassed the entire rocket with 4oz. fiberglass. That was quite a job, but the body tube now has a gratifying sturdiness without the brittle nature of P.M.L. phenolic. 

The kit is reasonably well designed, but the instructions were rough. I had to get replacements for two centering rings where were too loose over the motor mount tube. Other than these glitches, it was a pretty standard high-power rocket. 

The kit did not include provisions for a recovery system on the booster stage. I decided to use 1/2" nylon webbing for the recovery harness and Sky Angle parachutes (from The b2 Rocketry Company so I didn't end up using the Rocket Dyne Systems recovery components anyway. 

To air-start the sustainer, I built a bay between two fins of the sustainer and am using an Olsen Advanced Electronics ez-timer to fire the second stage. These timers are nice and compact and the LCD display is comforting: you know exactly what the timers are set for and have a persistent continuity display. 

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