Project
413 Flights - IE24E engine test

Results

• Besides the first day I launched a rocket, Flight 01, this was by far the most rewarding launch day I've ever had. Eight out of eight engines worked flawlessly. Six of the engines were flight tested and two were static tested. The main focus of these tests was to evaluate revision E of the IE24 engine. Of course there were other problems, the cylindrical fins were heated by the hot exhaust gas and melted off the rocket halfway in flight causing instability. The first static test had a 2" PVC cap on the end of the engine which was pushing on a hydraulic cylinder. Halfway through the test the cylinder broke through the PVC cap producing erratic thrust data. See video. After the first static test the pressure gauge was stuck on 140 lbs. and would not zero out so the second static engine was just launched. Even with all these problems, the main objective of the 413 engine tests, to produce a stable engine, was an overwhelming success. I think I finally have an easy to produce, low cost power plant that can now be used on larger projects.

Construction

• Engines were made from 2" Sch. 40 PVC 24" long. See IE24 engine construction instructions when completed. Engine nozzles were cast in the engine casing and restrained by four 1/4-20 x 1/2" steel bolts. The engine end cap was made with silicone and Pourstone, silicone sealing between the Pourstone and the casing wall. A 1 1/4" PVC end cap was inverted and put on top of the Pourstone, then restrained with four 1/4-20 x 1/2" steel bolts. Four 3/16" aluminum rods 18" long were used to hold the cylindrical fin section aft of the engine nozzle. 4-14 aluminum lugs were used to connect both ends of the rods with the engine and fin section. The fin section was made of 6" sections of 2" sch. 40 PVC. There was a 2" section of fuel used as tracer smoke and a 1/2" PVC union with .003" brass shim stock acted as an ejection charge.

Pros

• Total rocket weight was 8.76 lbs.
• Center of pressure was 12.4" from engine base.
• Center of gravity was 13.5" from engine base.
• Stability was .46 caliber.
• Engines were extremely easy to construct.
• Engines cost less than $3 each.
• Rockets cost less than $10 each.
• Engines proved reliable for larger projects.
• Silicone prevented end caps from leaking.
• There was nominal erosion in the nozzle throat.
• Launch rail guides worked well.
• Nozzle retaining bolts worked well.

Cons

• Fin rods heated and melted the PVC holding them in halfway through flight causing instability.
• Cylindrical fin design adds allot of drag.
• Recovery needs work.
• A new ignition system is needed. The car battery melted the micro switch used in the pressure switch making it useless.

Pictures

• Empty engine casing with nozzle restraining bolt holes.
• Restraining bolts and rail guide in place on engine casing.
• Completed engine casings.
• Nozzle molds next to engine casings.
• Close up of nozzle molds.
• Completed nozzle with high temperature paint added.
• Fuel slug for tracking smoke.
• Fuel in engine casing and igniter added.
• Bowl of igniters.
• Silicone put around inside of casing and allowed to dry.
• Working on the engines.
• Dual igniters, one for the engine and the other for the tracking smoke.
• Smoke vent holds drilled in casing.
• Completed engine with ejection and smoke.
• Close up of ignition wires.
• Nosecone added to engine casing.
• Making ejection rupture discs.
• Six flight engines fueled.
• Polyurethane caps added to nozzle throats to prevent fuel from absorbing moisture.
• Completed engines for flight tests.
• View of ejection discs.
• Lugs used to hold fin sections.
• Nosecone in mold.
• Completed nosecone.
• Couplings were first used as fin sections but were later changed to a larger design.
• Nosecone with streamer attached to stainless steel lanyard for recovery.
• Pile of nosecones.
• Fin sections with lugs.
• Completed rocket.
• View of fin rods attached to engine casing.
• View of fin rods attached to fin section.
• Stainless steel lanyard attached to ejection charge.
• Rockets with lanyards.
• Rockets ready for flight in the desert.
• Me next to all six flight tests.
• Ignition wires attached.
• Rocket #1 on launch rail.
• Nozzle after firing. Note the melted plastic where the lugs were. Nozzle is wet due to cleaning.
• Inside view of the end cap after firing. Note the silicone still in place. Nozzle is wet due to cleaning.
• Divergent section view after firing. Nozzle is wet due to cleaning.
• Convergent section view after firing. Nozzle is wet due to cleaning.
• Flight 01.
• Static 01.
• Flight 02.
• Static 02.
• Tracer smoke from the vents.
• Flight 04.
• Flight 05.
• Flight 06.

Video

• Flight 01
• Flight 02
• Flight 03
• Flight 04
• Flight 05
• Flight 06
• Static 01

CAD Drawings

• 413 rocket design
• IE24 engine design

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