Christopher James Huff

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visits member for 1 year, 4 months
seen Mar 13 at 11:44

Apr
10
awarded  Nice Answer
Mar
5
awarded  Citizen Patrol
Dec
30
revised Do spacecraft engines suffer from carbon accumulation the way typical petrol/kerosene engines do?
added 146 characters in body
Dec
30
awarded  Commentator
Dec
30
comment Do spacecraft engines suffer from carbon accumulation the way typical petrol/kerosene engines do?
This is simply wrong. LOX/RP-1 rockets almost always run fuel-rich, as a high temperature oxidizing environment would be hard on the engine components. The RD-180 seems to be the only rocket that actually runs oxidizer-rich, and it took careful design to handle the resulting high temperature, high pressure oxidizing environment. (Lumping oxygen and alcohol together doesn't make any sense either...alcohol's a fuel, like kerosene.)
Dec
30
comment Dynamics of a Rocket
@flamearchon: It's not really feasible to make it go in a straight line, and certainly not ideal. I'm not sure what the difficulty is. You model the motions as a result of the forces on the rocket, and the correct trajectories arise as a result of those forces just as they do in nature...you don't have to do anything extra to force the rocket to move appropriately. To model turning of the rocket, you simply apply the thrust in a different direction.
Dec
30
comment Why do space crafts take off with rockets instead of just ascending like an aircraft until they reach space?
It also might be informative to read up on the "Air Breather's Burden": islandone.org/Propulsion/SCRAM-Spencer1.html
Dec
30
comment Why don't rockets tip over when they launch?
Another possible source of confusion is the misconception that gravity will pull a rocket over, due to thinking it is "supported" against gravity by the engines at its base. Gravity (apart from very weak tidal forces) acts on the rocket as a whole, not applying any torque. en.wikipedia.org/wiki/Pendulum_rocket_fallacy
Dec
30
comment Why don't rockets tip over when they launch?
That's fine for model rockets, but orbital launchers rapidly leave the atmosphere. CP is only relevant for the first minute or so of launch...and isn't relevant at all for launches from airless bodies. The answer is simply that they're actively stabilized, against both aerodynamic forces when present and any other small imbalances and misalignments in thrust. For an extreme example, a recent Falcon 9 launch lost one engine on the way up, along with an aerodynamic cover for the engine, but the guidance system was able to compensate.
Dec
30
answered Do spacecraft engines suffer from carbon accumulation the way typical petrol/kerosene engines do?
Dec
30
comment Why do space crafts take off with rockets instead of just ascending like an aircraft until they reach space?
@jokoon: Spacecraft are launched from planes...and the Pegasus system happens to be the most expensive way to deliver payload to orbit in existence, on a cost per kg basis. Vertical launch pads aren't "risky", and you don't save anything by putting the pad support equipment on a giant aircraft that has to fly around before launch...and dump the rocket and payload somewhere if there's a technical issue preventing launch. Reuse of the plane means nothing...it's just an airborne launch pad (the altitude only matters for tiny rockets), and the vertical launch pads are reused as well.
Dec
30
answered Dynamics of a Rocket
Dec
30
comment Two masses in deep space - collide or orbit?
Also note that orbital period depends on eccentricity...0.54 years is for a circular orbit with a constant separation of 10 m.
Dec
30
awarded  Critic
Dec
30
comment Two masses in deep space - collide or orbit?
"Next: make the object rotate wrt the barycenter. The masses are at rest (one wrt the other) ? Yes." No. Both masses are now in motion with respect to the barycenter and each other...not the initial conditions the question describes.
Dec
28
awarded  Editor
Dec
28
revised Deviation from Earth's orbit
added 26 characters in body
Dec
28
answered Why don't astronauts in orbit get stuck to the “ceiling”?
Dec
28
answered Deviation from Earth's orbit
Dec
24
comment Why can't a superconductor make a DC motor self sustaining?
Electric motors convert electrical power to mechanical power, and work both ways...every electrical motor is a generator, and its motion produces a voltage that opposes the current through the motor. This is why stalled motors can draw lots of current and burn themselves out, and why a superconducting motor with no other losses would still have a voltage drop and require power input. Similarly, if you short circuit a motor, it becomes an electromagnetic brake...a superconducting motor with its terminals shorted together would actually resist rotation.