V2 up and running

After a few days of runs, we finally got the engine to run correctly.  Some of our tests burn over 10 seconds which is about as much as I can squeeze into the tank. There is a YouTube play list with all of the test runs including some good mach diamond shots during day 3. HolliStar Liquid Rocket Engine: HolliStar Liquid Rocket Engine: http://www.youtube.com/playlist?list=PLPs8paqlFtFy6ad9Riu9larwPlQGtC6eC

Rocket Test Aftermath and Analysis

Surprisingly the coolant line burst and the brass fitting exploded.

This was the same hose that blew up in my face a few weeks ago.... apparently it is back for round two!

Its fairly safe to let the excess methanol burn off.

First look inside the combustion chamber

The injector plate is unscathed.

One good note is that the hottest part of the rocket (throat/nozzle) are completely untouched.

Exactly what I thought would happen happened. When I mounted the rocket on the thrust stand, I noticed that water was leaking into the chamber. I spent two days running through the scenario in my head and what happened is that the coolant is ~50 psi and the chamber is 300 psi. The hot gasses pushed their way around the gap and into the coolant line which causes the water to boil. The steam doesn't cool at all so a hot spot forms which melts the aluminum. This progressed along the chamber wall until the hole was over the coolant outlet. The pressure then pushed its way into the line which cause the explosion and exploded the fitting.

Now that I know the concept works (when everything is sealed properly) onto V2!

SUCCESS!!!!!

HolliStar hot fire was a 100% success! Even the fireworks at the end were exactly as planned!

After two weeks and $187 of nitrous, an oxidizer solenoid bypass was used to get an igniter to burn in the chamber. Then comes the countdown 3...2...1...
The engine boomed into a roaring thunder that the recording does not justify.... FINALLY, its resounding bawl unshackled me from the cantena of unsuccessful attempts that had burdened me with doubt.The engine operated exactly as I spent over 400 hours designing, building, and assembling but it would never have been possible without the help that I got along the way. It was a wholly humbling experience.
Assuming that because I am an Aerospace Engineer, I am rocket scientist, was entirely false. The knowledge is potential. Conversion of potential to action is power. I can see now that all of the education that I received was simply following in the footsteps of great men. However, an Aerospace Engineer along with the help and support of:

Most importantly, thank you Lexi Soya. I don't know how you were able to tolerate my 24/7 rocket building schedule. You not only supported my investment of time and attention but encouraged me to keep pushing for my goal. There were many times where I came home simply defeated but you wouldn't allow me to give up...you and your contagious optimism. I didn't stand a chance and I thank you for it.

Thanks to Geoff Hollis, whom which the HolliStar Rocket is named after, because if he didn't teach me everything I now know about machining, it would have been impossible for me to build. He offered me his giant endmill, rotary table, indexing head, gallons of methanol from his slingshot dragster, his lawnmower battery, a military grade starter coil, welding of my custom tanks and most importantly insight for taking the ideas off the paper and realizing them.  Apart from that, he spent just as much time as I did rolling around on the floor getting it all to fit together and even lit the igniter in the video.

Brainstorming and Imagineering

Rick Pelfrey

Jim Kopasko

Suele Kabir

Electronics Consulting

Rhett Ward

Paige Harris

Dan Baumann

Unknowing Test Subjects

Branden Wright

Alex Soya

Logan Soya

The Mom Squad

Angel Brewer

Zee Soya

Encouraging Supporters

Rhett Brewer

Brandon Brewer

Jay Bracht

Emma Baumann

Jeff Gallese

Victoria McMurchy

Alex Cummins

Josh Cummins

Mama Cummins

Papa Cummins

Jon Thorton

NOW ONTO THE ROCKET!

I designed the rocket to operate for about 5 seconds and it operated perfectly through 3 seconds. I knew that there was a water leak into the chamber and that there would be a chamber burn through because of it. So even though the test ended in rapid disassembly, it went exactly as planned. I figured I may as well test how bulletproof my chamber since I was at it.

At start-up, you can see sparks from the aluminum melting where the coolant is leaking.
Next, the engine operates perfectly as the chamber heats up to half of the temperature of the surface of the sun.
Then the burn through happens.... fortunately the blast chamber held up!
Completion of a perfect first test run!

Though you can see 5 mach diamonds in the thrust, there were many more. The entire length of the flame had progressively weakening mach diamonds. I shot the video with a ND4 (Neutral density filter similar to sunglasses where I can take a 5 second picture in broad daylight) and it was still blown out by the white hot flames. I need to do more research as to how to record them.

Pictures of the aftermath and more analysis coming soon!

Day 30: Custom Tanks

We got sick of refillling the tiny tank every two runs so I designed these 1/2 gallons tanks. A little bit of an upgrade from the 1/3 of a liter one we were using! Of course, Geoff laid down a perfect triple weld on the end caps. I only needed 0.083 inch thick walls for 1500 psi so the 0.250 inch thick walls will be more than enough.