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shynung

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Everything posted by shynung

  1. We know there's a V8 car engine acting as the oxidizer fuel pump, so I presume the idle switch starts up the V8 and rocket igniter, and the full power switch gets the V8 to the redline.
  2. Cockpit of the Bloodhound vehicle. Apparently, much of the driver's view would be the instrument panel; that LCD above the steering wheel is pretty high to look over.
  3. Which is telling. Hybrid rockets aren't really known for high specific impulse. It's barely better than a typical solid rocket booster.
  4. I'm guessing that the rocket's dV budget isn't enough to push the car to 1000 mph, that the rocket runs out of propellant before the speed is reached. The jet engine may be there to ease the dV burden on the rocket, reducing propellant mass requirement.
  5. Jet engine usually come with some sort of alternator, so probably not necessary. However, jet engines are more fuel-hungry than piston engines, and taking electrical power from the jet would reduce thrust it produces. Makes sense to use the alternators on the V8 instead. A monopropellant turbo-generator can also provide auxiliary power without needing the rocket engine being on. Though, again this would be a bespoke design. The V8 is the easier solution to implement. Though, I have a feeling that a Mazda rotary engine would have been more appropriate, due to their high power-to-weight ratio. I guess they chose a Jag engine because the team is based in the UK, and procuring Jag engines may be easier.
  6. True, though that comes with the advantage of a vastly simpler pump that doesn't require another type of fuel (gasoline) to be brought onboard.
  7. It's possible to control the thrust by a throttle valve just before the pump, if using a turbopump.
  8. They could've gone this route, since their oxidizer is HTP (peroxide), which is a viable monopropellant. Why they didn't, I haven't an idea.
  9. Fun fact: a Jaguar supercharged V8 engine is used to power the oxidizer fuel pump for the Bloodhound's hybrid rocket.
  10. Even better, we can put the engines ahead of the crew compartment, and leave the tether extended. This not only puts some distance between the engines and the crew (which can reduce the mass for radiation shielding), but also makes the G vector during thrust and spin identical.
  11. I understand. I simply put forward another method of getting 1G via rotation that's far less mass/resource-intensive, which I think is more appropriate for a ship. For stations, rings are more acceptable, but as you say, we run into the size problem.
  12. Not necessarily. If we can, for example, build a tail-heavy long ship (CoM as near the tail as possible), we can make a ship that's less than 500m long. Still much longer than the ISS, but at least it's a bit simpler to build.
  13. You're talking about a relativistic projectile. These move at considerable fractions of light-speed, and needs large amounts of energy to throw. Nevertheless, going this route, even a small projectile can impart a considerably large kinetic energy.
  14. I agree, that system is not really suitable for a mobile onboard ISRU. Much better for a lunar base. The silver lining on that system is that the process requires lunar regolith instead of water(LH2/LOX), of which the former is much more abundant than the other. I can see an Al/LOX hybrid-rocket-powered lunar SSTO shuttle being feasible with that setup.
  15. Think of it as a sugar-KNO3 rocket. The aluminium powder/pellets could be mixed with a setting binder, then poured/cast into the cylinder, which is set afterwards. The tricky part is designing the binder material - it needs to flow while still in the ISRU/refueling equipment, then solidify/set after it's in the cylinder in an acceptable period and manner, kind of like cement. To be sure, this is kind of a complicated procedure, better suited to a workshop or garage. However, assuming you can set up such a workspace and there's alumina to be mined, this is one way to refuel a Al/LOX hybrid rocket.
  16. You can, if you store the aluminium in powdered form or as pellets. Of course, this means the equipment to refine aluminium for use in a refueable hybrid rocket needs to form powder or pellets, which would make them heavy and complicated.
  17. I think it's easier to add an upper stage instead of modifying the SM to hold more propellant/add drop tanks. The latter requires a significant redesign of the SM to make space for a bigger propellant tank, or strengthened side-mounting points and plumbing connections for the drop tanks to bolt onto. In comparison, the former simply means stacking the SM onto the aforementioned upper stage using existing mounting points.
  18. Forgot. I agree that hydrolox boosters aren't really efficient for strap-on boosters. Much better off going the SRB route. Though, I do question whether we can do away with a detachable skirt-mounted engines by substituting more SRBs. Basically, let the SRBs handle the launch TWR, and have the core be some sort of sustainer motor, much like how the old Space Shuttle stack was. So the booster configurations would primarily be Core + Upper stage, adding SRBs as necessary.
  19. I suppose not. But you can compensate by using a smaller core booster, a la Soyuz.
  20. @sevenperforce If launch TWR starts to be an issue, you can always slap a few solid rocket boosters on the side of the core. Or give the 4 skirt-mounted RS-25s their own tanks, mounting them as side boosters instead of main core engines.
  21. Vouching for this combo too, for the same reasons. Might also upgrade to methane/peroxide if ISRU capability is considered, just need to have a stock of catalysts (2-ethylanthraquinone and palladium) accessible.
  22. RCS and OMS generally used hypergolics because the engines that use them can be throttled very far down, and can start and stop nearly instantly, which is critical for controlling spacecraft orientation. Using propellants that need external ignition systems may introduce delays into the operation of the RCS/OMS that degrades the craft's orientation capability.
  23. If two supersonic planes pass each other too closely (i.e. plane A goes north, B goes south, 100 m distance at closest approach), would the pilots hear each other's sonic booms? Would the planes sustain damage from such an encounter?
  24. Which is why I intended this kind of thing to be a strap-on booster rather than the core - they're meant to be jettisoned pretty early on. They'd be using gas-generator cycle engines, sacrificing some specific impulse for pure TWR. Well, yeah. We can make the wings wet, though that would make them thicker, creating additional drag. OTOH, I'm also thinking of a blended wing-body rather than a winged-tube booster. Almost all of the internal volume could be used for propellant, plenty of space in the back for mounting several engines side-by-side, without sacrificing effective wing area. Of course, the additional drag is still there, plus the manufacturing costs would be much higher due to the complicated shape.
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