Project
920 Flight.

Results

• Five out of six engines worked perfectly. The one engine that failed had an experimental epoxy / Kno3 nozzle which blew out. Unfortunately it was also the first static and when the nozzle blew out it damaged the pressure gauge which was being used to measure specific impulse. Because of this, the following static tests could not use the hydraulic gauge.
• Members of San Diego Rocket Society were out as well testing various sorbitol / Kno3 engines.

Construction

• One static had a nozzle made out of epoxy and Kno3. The thought being that the nozzle would burn and act as a smoke tracer after the engine had been spent. I still believe this idea could work with some structural modifications. But for now I'm going to focus on the IE24 engine which seems to be working fine now.
• One static had a total of 1% black iron oxide added to the normal fuel mixture.
• One static had a total of 1% red iron oxide added to the normal fuel mixture.
• One static was made from the normal fuel mixture.
• Two "dirty" flight tests with the normal fuel mixture were to test the engines in flight. When the engines are being static tested, the end cap is pushed hard on the ground. This may have the effect of preventing what would normally be an end cap failure by holding the end cap in. The flight tests were to make sure that the end cap design was solid. No nosecone or fins were used on the "dirty" flights. A 2" x 3" ABS reducing coupling was attached to the aft end of the rocket. 24" of cellular ABS pipe was attached behind the coupling. A few 3/4" holes were drilled in the top of the 3" pipe to prevent the exhaust gasses from the engine from forming a vacuum. This design had it's share of drag and it was far from perfect but it did serve it's purpose in keeping the rocket stable long enough to test the engine end cap.

Pros

• I think the IE24 engine is finally getting to the point where it will be able to be used as a reliable power plant.
• Smoke tracer nozzles are a good idea and merit investigation in the future.

Cons

• None.

Pictures

• A "dirty" rocket design finished on the work table.
• Myself and members of SDRS in the desert.
• First static test with an epoxy / Kno3 nozzle.
• Static test with black iron oxide.
• Static test with red iron oxide.
• Static test with sugar / Kno3.
• SDRS flight with a 1.5" fiberglass sorbitol / Kno3 engine.
• SDRS flight with a 1.5" PVC sorbitol / Kno3 engine.
• First "dirty" flight.
• SDRS static test of a 1.5" PVC sorbitol / Kno3 engine.
• Second "dirty" flight.
• SDRS static test of a 1.5" PVC sorbitol / Kno3 engine.
• SDRS flight and recovery with a micro hybrid engine.
• SDRS flight on an "E" engine.
• Members of SDRS

Video

• Static test 01 with epoxy / Kno3 nozzle pressure gauge only.
• Static test 02 with black iron oxide.
• Static test 03 with red iron oxide.
• Static test 04 with sugar / Kno3.
• Static test 05 SDRS 1.5" PVC sorbitol / Kno3.
• Flight 01 SDRS 1.5" fiberglass sorbitol / Kno3.
• Flight 02 first "dirty" flight.
• Flight 03 SDRS 1.5" fiberglass sorbitol / Kno3.
• Flight 04 second "dirty" flight.
• Flight 05 SDRS 1.5" PVC sorbitol / Kno3.

CAD Drawings

• 920 engine design.
• 920 "dirty" rocket design.

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