Homemade Hybrid Rocket Test #3: Explosion

An unfortunate incident which temporarily brought a halt to my hybrid rocket engine experiments.

On its first test with the newly-fitted electric valve and larger 10-pound nitrous oxide tank, the paraffin-fueled engine suffered a catastrophic pressure-vessel failure and exploded. Before doing so, however, it managed to lift itself and almost 34 kilograms (75 pounds) of concrete nearly a half metre into the air!

The burn was intended to test the effectiveness of a rubber washer embedded in the fuel. This washer would theoretically disturb the oxidizer boundary layer flowing over the fuel, creating turbulent flow and leading to a more thorough mixing of oxidizer and fuel.

Despite the small amount of fuel actually consumed, a tremendous amount of energy was released, as the extensive damage clearly shows: the aluminum casing was peeled completely back, all the steel retaining bolts were either bent or sheared off, the cast-iron end caps were shattered and the concrete block the assembly was attached to cracked in half. In the end, not a single piece of the actual cylinder was remained useable!

Thankfully nobody was hurt. Construction of a stronger engine - constructed from a 3000-PSI rated hydraulic cylinder - proceeded immediately afterwards, and all further tests have been conducted with all personnel safely behind an earthen berm!

Category:

Science & Technology

Tags:

• Hybrid Rocket
• Explosion

[CanadianMacGyver]

I didn't know it was going to explode. The camera angle was chosen to capture the exhaust plume. If you notice, the engine moves off-camera before exploding; there was little I could have done about that.

[porpoisefathom]

im doing pressure vessel tests right now- does your pressure vessel need to be aluminum to keep weight down??-- if not try ferro-cement, 1/4 inch thick. what is your goal in the testing?..r u going to scale it up?

[kamratframjandet]

Not the best choice of camera angle.

[murdelabop]

Now _that's_ a RUD!

[SepradistPhantom]

Wow... what sort of thrust does that work out as? Impressive, if dangerous, but i think you could do with a better starter system while you're at it ;)

[soverato3]

WOW thats allot of pressure!!

[stdavross666]

wow pipe bomb luck you wasnt in the wqay