Project
717 Flight

Post-flight Analysis

• Another good flight with the current rocket design. The parachute failed to open due to the nosecone being attached too tightly to the rocket body too tightly. The rocket was recovered and it was confirmed that the ejection charge did fire but due to a design change, it had less power and did not dislodge the nosecone.
• 717 Flight time to impact was 32 seconds. Total take-off weight was 33.5 lbs.
• 626 Flight time to impact was 29 seconds. Total take-off weight was 33.5 lbs.
• 605 Flight time to impact was 35 seconds. Total take-off weight was 33.0 lbs.
• Also tested were two static engines with two different catastrophic failure inhibitor designs. One used matt board to crack and inhibit the fuel and the other used 1/4" 23 gauge galvanized steel mesh cast in the fuel to give it strength. Both tests failed.
• This flight brings the J300 consecutive successful firing to 38 out of 38.

Construction

• 6" ABS.
• Four J300 engines.
• Matt board / balsa wood fins.
• Plaster gauze nosecone filled with two part marine foam
• 7' plastic parachute 2 mil thick with 8 lanyards and a 25' x 3/4" nylon webbing strap.

Pros

• Good rocket body design.
• Easy to construct.
• Low cost.
• Good performance.

Cons

• The parachute ejection mechanism needs work.
• Since this rocket was recovered, I noticed that there was a good deal of erosion on the inside of the ABS fin section. This erosion was only directly below the nozzles which isn't surprising since the engine nozzles actually overlap the ABS pipe in the fin section. This is obviously an area that is lowering the performance of the rocket by reducing the amount of thrust that is actually transferred into work. This may need to be altered in the future.

Pictures

Video

• Flight
• Static 01 with CFI
• Static 02 with CFI

Drawings

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