Talk-Polywell.org

How come nobody caught my mistake? Hydrogen is only three and a half times better per unit mass than water at holding heat. Plus the density is so low that pumping enough mass through is going to be tough, particularly since the compressibility is non-negligible. Maybe we're better off just using hi...

Hmm... One of the problems is that the optimal shape for a QED rocket is a cylinder because of the magnetic shielding requirement, whereas the optimal shape for a ramscram is probably a movable three-sided box shape protruding from the airframe. It's really difficult to do structural morphing with a...

Maybe I'm looking at this thing sideways. How hot can the hydrogen in the cooling loop possibly get? There's going to have to be a refrigeration loop in order to get the regeneratively-cooled propellant mass flow rate down to a reasonable level, isn't there? Of course, gaseous CO2 probably doesn't c...

Funny; I was thinking something similar for my ion turbine concept - my chosen propellant was liquid nitrogen. Ease of fueling, you see... I wouldn't start out with empty tanks, though. If the refueling system failed in transit you'd be out of luck. Since the propellant isn't hydrogen any more, the ...

Okay, so no one noticed... Unless you want to use the aeroshell as a heat sink (you don't), you need to dump the hot hydrogen from the reactor cooling system somewhere, preferably into the engines. This is what Bussard called the ARC (All Regeneratively Cooled) design. Since you now have to dump tan...

I've been reading an old paper about the QED engine spectrum, and apparently the spaceplane concept involved using conventional turbojets to get up to Mach 2 - 2.5, then QED rockets for the remainder of the flight. Total Isp was estimated to be similar to that of a turbojet (maybe up to 2500 s or so...

I'm dubious about biomass. It requires either waste streams that match or exceed our liquid fuel requirements over an indefinite period of time, or farming wasted on fuel production. If it's possible to extract CO2 straight from the air industrially and make it into liquid fuel (I'm pretty sure it i...

Let me add that the CO2 hysteria is bunk. I'm down with that. Lots of people aren't, however, and on the off chance that it IS a problem, it would be nice to solve peak oil and CO2 in one shot, without changing our automotive technology or distribution system. If Polywell doesn't work, we aren't sc...

I think that if you're running a horizontal-takeoff-and-landing spaceplane (reduced gravity losses) with combined-cycle QED engines (ie: airbreathing below some substantial fraction of orbital velocity), your SSTA should be capable of lofting a reasonable boronated-water shadow shield. Say... if we'...

I had an idea a while back that involved using space elevators to orbit large solar power stations, with which you could run air refineries to produce gasoline, kerosene, and diesel. This process is completely sustainable, the net CO2 emissions are zero, and we're getting really good at making sure ...

Solutions that require being at Jupiter's core are non-starters. Room temperature hydrogen at 200 psi is supercritical. The question is, how much heat capacity can you pump through the coil sheath without destroying it? Hydrogen is less dense than water, but its specific heat is three and a half ti...

I suppose we'll just have to advance the state of the art.

What if you did something dumb like using high-pressure supercritical hydrogen instead of water?

You may be right, but Polywell has an advantage fission doesn't. It doesn't take days to start up or shut down. Actually, there was a thread speculating about this recently. About three days to manage outgassing in the vacuum chamber and other things as well. That's why I said HOT-restart. Everythi...

You may be right, but Polywell has an advantage fission doesn't. It doesn't take days to start up or shut down. If you could hot-restart very very easily, a bit of extra hardware might allow PWM-type throttling of reactor output, whereby 50% power is supplied by having the reactor on full blast 50% ...

The general consensus seems to be that the primary inefficiency in a high-gain reactor design is coil occlusion resulting in fusion product loss, which is expected to be about 20%. This energy is not completely lost, since you can run a steam power cycle on it, but in space you probably wouldn't bot...