I'm trying to (notionally) design a spaceship (hereinafter the "Truck") which won't be spending much time in the atmosphere except for fueling and loading. I'm also trying to reduce development cost by not including features found in the Sexy Beast (e.g. Holbach array fans, electric turbines, REB for supersonic flight, etc.) and using a big helicopter.
In every respect (except for two) I expect the Sexy Beast will be a superior vehicle compared to the Truck. I'd also expect the Truck to take less time and money to develop. Otherwise, the Sexy Beast will probably be the winner in whatever category you name.
DeltaV wrote:Hope your rocket consumes less than the SSME.
SSME is not the example to use. The Sexy Beast and the Truck use the same rockets powered by a Bussard. The Truck makes the transition to rocket flight a lot earlier than the Sexy Beast. So, if
DeltaV wrote: Polywell should have power to spare before orbit boost.
We can wait while the rotor stops and stows. It won't take that long.
rjaypeters wrote:Before re-entry, we have the choice of lifting the blades away from the body and aligning them above the hub before starting their rotation or just leaving them along the body. I'd prefer to leave the blades along the body and use the sink rate airflow to help lift and auto-rotate them.
DeltaV wrote:Deploying them before reentry guarantees they melt or break off.
No, it doesn't. The Truck will not be using a ballistic reentry, but a semi-ballistic and powered one (so, slower). And as I wrote, I don't prefer lifting the blades above the hub and behind the body (wrt to local airflow) before re-entry.
Further on the subject of powered re-entry, the Truck won't need as much TPS because it will be moving slower through the atmosphere.
rjaypeters wrote:I'm not saying VTOL fans won't work. I am saying for the equivalent lift, helicopter works better and is lighter.
DeltaV wrote:Polywell should have power to spare before orbit boost. Lots of lift fans if needed. Two helo rotors can't lift that much, and only give one level of redundancy, assuming they're cross-connected. Eight lift fans can tolerate losing two or three. Don't forget the complexity of rotor heads, gearboxes and cross shafts compared to Halbach rim-drive motors.
I really like the Halbach rim-drive motors. I like better that helicopter technology is well understood.
DeltaV wrote:Jumping from helicopter to rocket means you'll need to carry a lot more reaction mass, especially with the hover time needed for blade stowage.
Now, we're just going to have to run the numbers.
rjaypeters wrote:The helicopter removes the weight of the REB equipment
The Truck doesn't carry the REB.
rjaypeters wrote:and lets us carry (in fact, requires) more reaction mass.
Carry more, no. Sikorsky Skycrane payload is 20,000 lb. Think you're going to go orders of magnitude beyond that?
Yes, what is this project about if not going far beyond what has been done before?
rjaypeters wrote:On another point, these vehicles are going to be heavy. I'm guessing around one million pounds. We're still going to need landing pads, but flame buckets won't be required.
DeltaV wrote:So the low disk loading of helo blades becomes moot.
No. A concrete landing pad is a lot easier to build than a flame bucket.
rjaypeters wrote:I don't see loiter or atmospheric cruise as requirements which should drive the design of the first generation Polywell SSTO. IMO, high speed and/or extended flight through the atmosphere is not what we should be designing for in the first generation Polywell SSTO.
DeltaV wrote:That's trivial compared to getting to orbit. Atmospheric cruise lets you pick your orbit and your takeoff/landing locations. So you want to limit yourself to a few orbit inclinations and one or two launch/landing sites, like Shuttle?
I don't think high-speed flight through the atmosphere is trivial.
No. Pointing the Truck in the direction you want before rocket boost changes your orbital inclination. Orbital changes are orbital maneuvers. Making a big change in landing site is an orbital and powered re-entry manuever for the Truck.
rjaypeters wrote:Once we understand the Bussard better (and can make it better), follow-on vehicles should have more difficult to satisfy requirements. Else, what would the engineers do?
DeltaV wrote:Go for broke. Before the daggum gubmint regulates it all away.
You mean like the X-33 program? Sorry, that was a cheap shot and not at you DeltaV, but at the (I'm trying to nice, here) people who spent millions on that waste of a program. [end of rant]