JP Aerospace Blog

We did the first two firings of the mini MHD generator today.

This unit can be unclamped and easily disassembled. This gives up a rapid turn around for a lot more testing.

Here’s a pics from our Away 25 mission at 100,000 feet.

Today we’re going to be working on the crew module mockup and the MHD generators. We’re experimenting with a stand up configuration for the crew for the module. The nice thing about a full size mockup is that you get to experiment and find out quickly what works and what ideas to later pretend you never had.

We’re finishing up a mini-MHD generator. This one will use even smaller rocket motors. The mini will be used as a base for testing the sensors. With the smaller engines we can fired several times a day pretty cheaply.  If all goes well with the sensor we’re going to try and get a firing in on the quads MHD generator.

We still have the 50 foot airbeam we want to test at 4 psi. However that’s best done outside and it looks like rain tomorrow, (we fire the rockets under an awning).

We’re been studying other people’s magnetohydrodynamic generators. This one is pretty interesting. It’s a Russian space based MHD generator that uses a liquid rocket engine at it’s core.

At least the Ascender is. Check out page 210 of the new illustrated edition of SuperFreakonomics. There is an illustration of two Ascenders carrying a hose up into the stratosphere. We consulted on that project and they went with Ascenders in their planning. However we were not credited in the SuperFreakonomics book. Oh well, you can’t win them all.  There are so many folks involved it would take an entire book just to credit everybody.

The Ascenders do look cool though holding up the hose to the sky.

Today we did the third test of our MagnetoHydroDynamic generator.

Not the rocket engine, nor the high powered amplifiers, or even the band saw can beat the Neodymium magnets as the most dangerous  thing in the shop.  Regardless of how careful we handle them you always get bit one way or another.

I went to get the  magnets to put them back on the MHD generator.  Each set was wrapped in three inches of bubble wrap then double wrapped in woven nylon bags then put in a box of packing peanuts. They had been in this box for about a week. All the while the pair had been slowly popping the bubble wrap and inching closer together. When the bubble wrap was gone they started compressing the plastic into a thin film. When I opened the box instead of finding two magnets six inches apart I found one solid block separated by 1/32 inch smear of plastic.

Two vices, four large plastic wedges, a pry bar and  hour and a half later they were separated once again ready for mounting on the generator.

A film crew was in Saturday to shoot some scenes for an upcoming show on JPA.  This was their third time shooting with with. Last summer they were out in the desert with us getting some action shots. The director says only one more session to go before to goes to editing.

We turned the cameras on them while they were turning the cameras on us.

At the end of a very chaotic day all that was left was the gaffer tape on the floor. The best guess is that this will all go to air in a few a months.

This is from the December 1931 issue of Modern Mechanix. It’s Robert Goddard’s patented Turbine Rocket. Is wasn’t designed to go to orbit. Just to the top of the Stratosphere.

We think we can get a couple more firings on the existing generator. The dozen cracks need to be epoxied. The anode and cathode have been pulled, caked on residue been removed and the copper polished. We’re going to up the data rate from 5 samples a seconds to 20 samples to second.  The data logger has an extra channel. We’re going to connect it to the motor ignition line. This will give us a clear start indicator in the data.

I put the Sky Pup through her paces at Franklin Field on Sunday.  Just a few feet up and runs down the runway. Things were more exciting on the taxiway though. About half way back the Pup started pulling to the left. I started putting in more and more right rudder to compensate. About three seconds later the landing gear failed, the nose went down and the propeller shattered against the tarmac.  The damage isn’t to bad, but the gear is pretty integral to the fuselage and will take some work to replace. The entire plane will need a pretty good inspection.

We finished the long airbeam for the High Beam mission.  We pressure tested and it held fine under the full load. It’s has enough strength however it wants to snap into an arch given any chance. Something new to tackle. High aspect ratio airbeam stabilizing.

We fired a model rocket engine (‘D’ sized) through the quad’s magnetohydrodynamic generator. The engine was significantly smaller than the quad. We wanted to give the unit and the data logger a shakedown under “hot” conditions. We were pretty startled by the performance. We saw twelve amps at one volt. The ceramic housing developed several cracks from the two firings we did and the cathode worked loose. It was a great first look at the unit. We’re going to rebuild the generator and do a few more of these firings. This will let us refine it a bit before the quad firing.

I like to do a simple sketch of each project we plan to do. This is the Transatmospheric Ascender docked to a small Dark Sky Station.