Project
Incendio engine 622 flight.

Construction

• The body for these four rockets was made out of 3" cellular ABS. Eight 5/8" holes were drilled in the top section to accommodate the tracer smoke and forward bulkheads.
• The nosecone was made from plaster impregnated gauze which was sanded, primed then painted. The nosecone was hollow which provided space for the recovery system.
• The fin section was made from 3" cellular ABS and suspended 12" behind the aft end of the rocket body by four 1/4" aluminum square rods. The rods were secured to the fin section and rocket body with four 6-32 x 1/2" pan head machine screws. Fins were constructed from 5/16" balsa wood laminated with single ply poster board on each side. Slots were cut in the balsa wood to allow two 3" fully threaded aluminum rods to be glued in after being threaded into the fin section.
• The engine was an Incendio engine with a reinforced end cap. Each engine was held in the rocket body by a length of 2" foam pipe insulation with a 3/8" thick wall.
• The two forward bulkheads were filled with a mixture of Pourstone and Perlite to reduce the weight of the Pourstone and add to it's heat resistive properties. Bulkheads were made from 2" ABS caps held in place with 1/4-20 x 1 bolts.
• There was a 22 second smoke delay (design) which turned out to be 30 seconds (actual) and a rupture disc that blew open the nosecone and released the recovery device.
• Two igniters lit the rocket, one the engine and the other the smoke / recovery device.
• Two 1/4" fender washers were used as guides for the launch rail. The washers were held in place by two 1/4-20 x 1 bolts with two 1/4" x 1/4" nylon spacers.
• The launch rail was made from a 10' length of 1 5/8" steel unistrut.

Pros

• The first flight was perfect. The second and third had structural issues and the fourth had a bent fin casing which caused it to go slightly off course.
• Rockets were easy to construct and inexpensive.
• The rear fin canister succeed in producing a very stable rocket.
• igniters worked perfectly.
• Smoke and ejection worked as designed but too late.
• Launch rail worked great.
• The fin canister design allows the rockets to be assembled at the launch site, reducing their size so that they can fit in the car.

Cons

• There was some added drag due to the fin canister being behind the rocket body but I think the added stability is a fair trade.
• Recovery timing needs some work.
• Engine design needs reinforcement to be reliable.

Pictures

• Balsa wood fins being laminated on one side with poster board and glue.
• Fin canisters in varying stages of construction.
• Completed fin canister.
• Engines in rocket bodies.
• Ignition wires, pipe insulation holding engines in rocket body and launch rail guides.
• Forward bulkhead holding smoke / recovery canister. Paper and epoxy is there to keep out moisture prior to launch.
• Completed smoke / recovery assemblies.
• PVC union holding rupture disc in recovery assembly.
• Holes in rocket body for smoke.
• Polyethylene cap in nozzle to prevent moisture from entering engine prior to launch.
• Ignition wires going through forward bulkhead.
• Smoke ignition wires connected to engine ignition wires.
• Completed smoke / recovery assembly in rocket body.
• Completed rocket bodies.
• Ignition leads.
• Fin canisters with square aluminum rods.
• Launch rail guides.
• Rockets with date designation added.
• Flight one ready to go.
• Can't hurt.
• Me next to the rocket in the desert.
• Excellent.
• All that stuff fit in the car.
• First launch.
• Landing site.
• Forward end of rocket showing smoke trails down the side.
• Second launch.

Video

• First flight.
• Second flight.
• Third flight.
• Fourth flight.

CAD Drawings

• 622 rocket design.

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