Project
1108 static tests

Results

• This was a good series of tests in that even though there were failures, they happened as expected. Tested was a new engine design in which the nozzle was made from a 65/35 mixture of epoxy and Kno3. The nozzle being flammable would act as a smoke tracer after the engine was exhausted. This design has several benefits listed below. The end cap design was also new and worked very well.
• Static 01 - the nozzle and nozzle retaining ring blew out of the motor. It was thought that if the engine failed, this would be the most likely point. A simple structural modification on the 1115 static tests should fix this.
• Static 02 - a perfect fire with 12 seconds of smoke.
• Static 03 - this was the prototype for this design and too much fuel was added to the engine. The final engine had 1" or about 5% more fuel than previous engines. When the engine ruptured due to over pressurization, it became apparent how close to the PVC's tolerance the IE24 engine design was. In future engines I will be removing 1" or about 5% of fuel from the engine to create a wider safety margin.
• Static 04 - a perfect fire with 12 seconds of smoke.

Construction

• The nozzle is cast in a short piece of 2" PVC pipe and a PVC coupling. After the nozzle is dry, the engine casing is added. This has the advantage of allowing access to the convergent section of the nozzle so that a small 45 degree convergent section can be added.
• The end cap is made from a 2" PVC cap with a .75" hole drilled in the top. When the PVC glue is dry, Pourstone is added to fill in the gap between the PVC and the fuel making a tight seal.

Pros

• Very easy to construct.
• Very inexpensive.
• The smoke is self-igniting so an extra igniter is not necessary.
• After the fuel has been spent, the total engine mass is reduced by an additional 5.8% as the nozzle is depleted.

Cons

• The engine has 19" of fuel in it which seems to be too close to the PVC's pressure tolerance. In future designs I will be removing 1" of fuel to reduce the pressure in the combustion chamber.
• The smoke could have been heavier. At high speeds it might be difficult to see.

Pictures

• The convergent side of the nozzle. There is no convergent section added yet in this picture.
• The completed engine.
• Nozzle plugged to prevent moisture from getting into the fuel.
• Static 01 sequence.
• Static 02 sequence.
• Static 03 sequence.
• Static 04 sequence.
• Nozzle burning on the ground from failed static 01.
• Nozzle burning on the ground from failed static 03.
• Nozzle burning on the test stand after a successful test.

Video

• Static 01
• Static 02
• Static 03
• Static 04

CAD Drawings

• None

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