The meeting has picked up again at 4 PM with a discussion by Mitchell Burnside Clapp on what Rocketplane is up to in Oklahoma.

Mitchell starts off by explaining that he has left Rocketplane Limited over “creative differences.” Apparently Chuck Lauer will give the Rocketplane Limited talk tomorrow.

Pioneer Rocketplane Corporation is not Rocketplane Limited, and he is still Pioneer Rocketplane, looking for what to do now. He has a new rocket engine cycle that doesn’t involve combustion, using differential temperature between the propellants. By running a heat engine between the two, you can generate the enough shaft work to pressurize the propellants, which makes for a much simpler pressurization system. He likes it because it involves no chemistry–just physics. “Worst thing that can happen when starting a jet engine is starting a fire, which you can run away from. A rocket engine can generate an “earth-shattering kaboom.” He thinks it’s a good thing to be able to test the pressure condition of the powerhead before ignition, and this would allow that. The idea is to allow a non-catastrophic engine start sequence. Looking at Stirling, Brayton and Rankine cycles (he currently favors Brayton). This kind of technology would mitigate his concern about vertical takeoff/landing.

They’re also doing a lot of work on hot metal structure. Inconel, stainless steel and aluminum have similar strength/weigh ratio, but elastic modulus is different. Nonetheless, he thinks that one can learn a lot about Inconel behavior by building airplanes out of stainless, so he’s doing some research in that area as well.

Talk was quite entertaining (as always), but he talks too fast to do the raconteurage justice on a typed blog.

In questions, a discussion about why Brayton is preferable to Stirling. In short, better power density. Preferred working fluid is supercritical nitrogen.