Inverse Engineering

Project
806 Sea Launch

Post-flight Analysis

It's hard to believe the entire Sea Launch was ruined by bad PVC glue. Well, at least that's the theory. 9 K380 engines were made for Sea Launch and all of them failed identically. These were the same engines that were static tested on 409 and flight tested on 507 with outstanding results. A new can of PVC glue was purchased before the construction of these engines. A few weeks ago on 717, a new type of engine was tested. The engine failed when the PVC fittings came apart from the PVC pipe they were attached to. At the time I didn't think anything of it. I just thought it was an experimental engine that failed but looking back on it, it was odd that the fittings and pipe came apart. The same glue was used to make the Sea Launch engines and I believe the cause of their failure was the result of a similar separation of pipe and fitting.
Alberto came up with the theory that the engine might have been sitting around too long before launch and the fuel some how became brittle. My gut tells me it was the glue, but with all the debris 200 feet under water, it's hard to come to a conclusion. A static test next month with the bad glue should tell us one way or another.
Alberto came up with an excellent ignition circuit design based on Richard Nakka's design. The circuit used a programmable PIC-16F84A chip to give us multiple events.
The floating launchers worked perfectly as did all the electronics. If the engines had not failed, this would have been a perfect launch.
Alberto put a digital camera in his rocket which took several pictures underwater before ignition and then several after the engine failed.

Construction

The rocket design for Sea Launch was identical to the 507 flight.
Take-off weight on my rockets was 43.5 lbs. each.
Take-off weight on Alberto's rocket was 12.5 lbs.
Launch tower was made of aluminum strut channel with 4" PVC drain pipe floats around the upper section.

Pros