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Project Details

Components:  The airframe is 7.5 inch phenolic tube. The upper airframe section is a three foot and the lower is four foot in length.. The nosecone is a PML fiberglass cone 29 inches long excluding the shoulder. I added nineteen ounces of weight in the nosecone. A three inch wide Kevlar tape is inset at the top of the airframe tubes for zipper protection. The three fins are 3/8 inch birch plywood. The centering rings are 3/8 plywood and motor tube CRs are doubled. The motor tube is 98 mm with a Aeropack retainer. I used a 98/75 mm adapter for the AMW 1350 motor. The altimeter bay is two separate 54 mm tubes located on opposite sides of the coupler in the upper airframe. The altimeters are on sleds that slide into the 54mm tubes. There are rotary switches located on the sleds which can be accessed with a screw driver through holes in the airframe. These switches are used to power up the electronics and shunt/arm the ejection charges. There is a Missle Works RRC2 one sled and a PerfectFlite MAWD on the other. Each altimeter is hooked to separate drogue and main charge. One sled has a Perfectflite MT3G Timer set to fire a backup drouge charge four seconds after the simmed apogee.
 
Construction: The airframe is glassed with Aerosleeves 7 inch fiberglass sleeve and West System slow epoxy. I used a rotissere to rotate the airframe while the epoxy was curing. The weave in the Aerosleeves is filled with Superfill epoxy filler also from Aerosleeves. My main gotcha was using an alignment template for the fins. After expoying the fins, I discovered one was out of line and I had to remove it and reposition. It would have been better to use a plywood fin jig. Six ounce fiberglass tape was placed across the fins roots and motor tube in the fin can.
 
Finishing: I used Kilz Original Primer followed by Krylon yellow gloss on the upper airframe and Krylon black gloss on the lower airframe. I consulted Dave Rose of Graphix N Stuff on the color scheme. He suggested a vinyl body wrap that provided a transition from black to yellow on the upper airframe. The body wrap was applied over the yellow upper airframe. This wrap was black vinyl with dots or holes in the vinyl at the bottom and transitioned to dots of black vinyl near the top.
 
Flight: I did a test flight on an AMW L1300 to 1350 feet with no problems. However, I decided to switch from a 48 inch nosecone chute to a 60 inch chute because the nosecone came down at about 28 feet per second. So I felt well prepared for the cert flight and chose an AMW 1350 White Wolf for the cert launch at the 2007 Florida Winter Nationals. The boost on the AMW 1350 White Wolf was fantastic. The altitude reached was 4340 feet which was more than I expected. The drogue charge may have been a little early. I cannot tell if the first charge was an altimeter or from the timer. The main and nosecone chutes deployed for a nice descent from about 1000 feet. The rocket was recovered only about 1/4 mile from the pad with no damage. I now have data from the PerfectFlight altimeter which will help me set the timer for future flights. It was closer to apogee that I planned. I want the altimeters to deploy the drogue. The timer is a backup.
 
Recovery: I chose the Giant Leap TAC-9B chute for the main. The main was in a deployment bag which was pulled off by the nosecone at ejection. The nosecone was recovered separately on a TAC-1 60 inch chute. I used a Giant Leap 24 inch TAC Drogue. I used lengths of two inch wide tubular nylon to get the shock cords out of the airframe for zipper protection. The rest of the shock cord was one inch wide tubular nylon. The drouge harness was 100 feet long and the main harness was 20 feet long.

Vendors:

Red Arrow Hobbies Phenolic tubes, CRs nosecone and custom cut fins
Aerosleeves Fiberglass Sleeve and Superfill
Shockcords.com 2 inch and 1 inch TN custom lengths, sewn loops and D Rings on the 2 inch TN.
Quickburst Large Ejection Canisters and custom Nomex Sleeves for 2 inch TN
Giant Leap Rocketry TAC Chutes: drogue, 60 inch for Nosecone and the big TAC-9B for the main.
Mr. Fiberglass 3 inch Kevlar tape and other Fiberglass tape
Aeropack 98mm Retainer
Missile Works Lots of the 220/110 switches and a RRC2 from way back.
Perfectflite The MT3G Timer and a MAWD
Graphix & Stuff Vinyl wrap and lettering.