I made my first attempt at Level 3 cert on June 3, 2001, this is the date of my 43rd birthday and it is also the date of one of our club launches at Octillo, CA.

Read the launch report here:

 ocotillo-6-2001.htm


Level 3 Project - RDS-NorthStar - Modified

I'm using the RDS (Rocket Dynamic Systems) North Star Kit as the basis for my level 3 certification flight.

I like the RDS Kits but for my Level 3 certification flight I felt certain modifications were in order. 

1. Glassing the entire body tube with one layer of 5 ounce S weave glass.

2. Building the fin can as a separate assembly which is completely glassed to the motor tube, middle and bottom bulk heads.

3. Creating a removable electronics bay that is designed to deploy either in single or dual modes.

Basic stats:

Length: 10 feet 

Diameter: 5.54 inches

Weight: 23.5 lbs. unloaded, with engine 33.5 lbs. 

Motor Mount: 75mm 

Motor: Aerotech M-1315 

The rocket consists of 1 45" inch body tube, coupled to two more 30" inch tubes. The nose cone is 21.25 inches to its shoulder and 26 inches in total length. The rocket will have two parachutes in dual mode and one larger chute in single mode.

Fin Can:

Me working on the fin can measuring for the aeropak retainer ring. This 75 mm retainer ring is the cleanest positive retainer system made.

When this picture was taken I had yet to glass the fin can but all fins were tacked in place with 1 inch 18 gauge brads through the bulkheads into the fins to place them.



Once all my measurements were taken, I reinforced the fin can with fiberglass and West systems epoxy. The instructions suggest that the motor mount be inserted into the body tube then epoxy the fins through the tube onto the motor tube, but I've since used building my fin can first as a unit then insert this whole completed unit into the body tube. This way you can get a much stronger fin can assembly by reinforcing the fins directly to the motor tube with fiberglass and resin.



Body Lay up: I changed my process about halfway through the building of the rocket after discussing fiberglass construction with a surf board builder. I had intended to use two layers of glass, much as others have done in our hobby but upon discussing this with a buddy at a local surf board manufacturing shop I changed my technique. His reasoning was the following: 1. Use S weave glass to get a stronger bond than regular glass. Use only one layer of glass to save on weight somewhat important given I'm only using a 75 mm motor. One layer is plenty for structural integrity and if there is a catastrophic failure, one, two, three layers of glass won't make any difference anyway. 

So I laid up using one layer of 5 ounce S weave, then also as suggested I then painted the rocket, then applied a "hot coat" of epoxy over the paint. The hot coat was nothing more than just kicking the epoxy to cure at an accelerated rate. This proved quite difficult and in fact I could not get the fin can finished in time before the epoxy gelled on me, this added additional sanding and grinding work to "clean" up my mess.


Electronics:

There's lots of great electronics on the market today. I have chosen to utilize Adept products. I will be using a redundant system. First, my primary system will the Mach Compatible ALTS25. It uses Adept's proprietary Real Time Dynamic LockoutTM system that tracks speed in real time to ignore pressure glitches that occur when transitioning through the sound barrier, both in and out. This system is possible due to the extreme precision of one-foot resolution measurements. It will be backed up by the Adept DDCS25 which is an altimeter based Dual-Deployment ControllerTM. It is exactly the same circuit as the ALTS25 Altimeter The DDCS25 does not report maximum altitude, but all other functions are the same as with the ALTS25. The DDCS25 was developed by Adept as a redundancy backup device to be used along with an ALTS25 or other device, or it may be used as a primary dual-deployment controller when the maximum altitude value is not needed or desired.

The rocket will be designed to utilize either single or dual deployment. The electronics chamber will be placed midway in the rocket so that it can fire either a single charge toward the nose cone deploying the main parachute or it can be set up for higher flights to deploy a drogue at apogee then the main at a user selected height.

Ejection system:

The electronics are connected by wire to the ejection charge which is housed in half inch copper tubing going through the electronic bay bulkhead into the open parachute chamber. After experimentation I settled in on 7 grams of 4F black powder to eject my parachutes.

The parachutes are made up of a 14 foot main and a 4 foot drogue which is deployed at apogee with the main deployed at 1000 ft. above ground. I'm electing to keep the whole rocket together and not separate it into two pieces. 

Deployment:

After a ton of tossing and turning I decided to follow the advice of many others in our club and utilize single deployment. While the rocket is set up for dual, there is no reason to push my luck. So single it will be!

45 " inch body tube 
2 30" inch body tubes 
75 mm motor mount tube 
4 .25 inch Baltic Birch Bevel- cut Fins 
30 feet of 9/16 tubular nylon 
30 feet of round shock cord 
2 Airframe couplers 
1 plastic Ogive Nose Cone 
1 .25" inch bulkhead and 2 .5 inch 
3 3/8" baltic birch centering rings 
Aero pack 75mm motor retainer 
2 brass launch lugs .5" inch 
4 1.5" U bolts 
Adept redunant electronics 
1 14 ft. Rocketman parachute with drogue and deployment bag 
1 4ft. Rocketman parachute with kevlar deflection shield 
4 3/8" inch diameter 4" inch long cast iron tubes used for ejection cans. 
Adhesives:

1. West Epoxy system used on all interior mounts and fillets.

2. CA used to seal all leading edges of body tubes.

Fiberglass:

One wrap of 5 oz. S weave glass. The glass wrap encompasses the entire body and fins. One additional coat of epoxy after application of the paint.

It is my intention to attempt certification on June 3, 2001 using a Aerotech M-1315. The flight will take place at my home club that flys at Ocotillo. Prior to that date, I will fly the NorthStar on an L-1120 at spring fest in Vegas on March 17, 2001 and again at Ocotillo at either our April or May scheduled

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