Search found 30 matches

by dkfenger
Tue Nov 04, 2014 11:14 pm
Forum: News
Topic: SpaceShipTwo
Replies: 37
Views: 17128

Re: SpaceShipTwo

There's some really good discussion on the NASA Spaceflight Forum. The consensus there seems to be that the feather unlock is done during the burn so that you have the option to abort the burn if it won't unlock. Once the burn is done you're headed for space no matter what you do. If you find out at...
by dkfenger
Mon Sep 16, 2013 7:24 pm
Forum: News
Topic: SpaceX News
Replies: 2324
Views: 1154738

Re: SpaceX News

Something that lofts 1200kg to LEO for $39 million is not a competitor for SpaceX. Epsilon is a solid fuel rocket, too, which probably simplifies the launch process. Using automation to cut down the number of people required is still interesting, though.
by dkfenger
Thu Jul 18, 2013 6:45 pm
Forum: News
Topic: everyone see this yet, a version of polywell
Replies: 10
Views: 6387

Re: everyone see this yet, a version of polywell

I think the 3D version could look like a geodesic dome. Place the inward facing solenoids at the vertexes, and the recirculation ones along the bars/edges. Built like that, there's plenty of room in between for support structure and wiring. I have no clue if it'd be superior or not in producing the ...
by dkfenger
Thu Feb 14, 2013 8:27 pm
Forum: News
Topic: Mach Effect progress
Replies: 2707
Views: 1466348

Re: Mach Effect progress

Doesn't the "rest of the universe" change with the vehicle's light cone (in connection with velocity)? That would mean no priviledged frame. Probably. It'd be an interesting problem to poke at if the ME-drive gave us the tools to do so. However, I'm not particularly worried about it. I'm inclined t...
by dkfenger
Wed Feb 13, 2013 9:53 pm
Forum: News
Topic: Mach Effect progress
Replies: 2707
Views: 1466348

Re: Mach Effect progress

The math for energy conservation was laid out quite neatly by a post from chrismb in General: http://www.talk-polywell.org/bb/viewtopic.php?f=8&t=4190 Any propellant-based rocket does not violate energy conservation at any speed, once you account for the propellant as well as the rocket. Period. I l...
by dkfenger
Thu Jan 17, 2013 9:07 pm
Forum: General
Topic: Rigorous analysis thrust/propellant power, arbitrary frame.
Replies: 4
Views: 3904

Thank you for this. I didn't like my earlier result, and I now see where I screwed up. Rounding 1.08N to 1.0N would only have been fine if I'd changed the propellant velocity to match. Without that, the KE calculation ends up unbalanced, and that's where the velocity dependence came from. I really d...
by dkfenger
Thu Jan 17, 2013 7:46 am
Forum: News
Topic: Mach Effect progress
Replies: 2707
Views: 1466348

Well you're not asking again. This is the first time you've asked for real M-E numbers. Ah, sorry. I rewrote the post where I asked for K scaling a few times, and I must have edited that bit out in the final version. The highest thrusts Jim has gotten were 130uN with about 1 watt dissipated. This i...
by dkfenger
Thu Jan 17, 2013 12:35 am
Forum: News
Topic: Mach Effect progress
Replies: 2707
Views: 1466348

Conclusion: you cannot ignore the nature of a non-inertial frame of reference and have more than a toy model. That's not 'analysis'. That's somewhere between handwaving and giving up. GR and SR closely follow Newtonian results in well defined regimes - inertial frames, minimal spacetime curvature, ...
by dkfenger
Wed Jan 16, 2013 5:50 am
Forum: News
Topic: Mach Effect progress
Replies: 2707
Views: 1466348

All thrusters have a stationary K. That is not to say that K is invariant. It is not. Could you point me towards some math on the subject, then? Specifically for Mach Effect thrusters, how does K vary with velocity along the axis of thrust, and with acceleration perpendicular to it? I've started wo...
by dkfenger
Wed Jan 16, 2013 12:15 am
Forum: News
Topic: Mach Effect progress
Replies: 2707
Views: 1466348

No. High velocities are the province of Special Relativity. That's not what we're here talking about. These are issues explained in General Relativity. Your high school text book did not say you can ignore that a reference frame is accelerating unless its velocity is very high. It said that all ref...
by dkfenger
Tue Jan 15, 2013 11:07 pm
Forum: News
Topic: Mach Effect progress
Replies: 2707
Views: 1466348

One does not need to be operating at relativistic velocities for relativistic effects to become obvious. Lorentz transforms generate different numbers than newtonian dynamics at velocities that one would casually not expect. Show me the math. For velocities four orders of magnitude smaller than the...
by dkfenger
Tue Jan 15, 2013 10:08 pm
Forum: News
Topic: Mach Effect progress
Replies: 2707
Views: 1466348

You won't see me handeling actual numbers the way engineers love to. Rather, I analyze the issues without numbers. Most engineers would count that as guess work but it is really not. What are the facts? Again and again and again – what are the facts? Shun wishful thinking, ignore divine revelation,...
by dkfenger
Tue Jan 15, 2013 9:32 pm
Forum: News
Topic: Mach Effect progress
Replies: 2707
Views: 1466348

In this case, a 40mg mass being ejected at 27,000m/s from a 1 kg mass is going to cause more than a 1m/s deviation in it! Covered above, but it's actually pretty close: 27000 m/s * 40mg/1kg = 1.08 m/s. This treats it as an instantaneous ejection rather than one that takes place over 1s, but to be h...
by dkfenger
Tue Jan 15, 2013 9:29 pm
Forum: News
Topic: Mach Effect progress
Replies: 2707
Views: 1466348

GIThruster wrote:I'm exhausted. Jim was right to warn me about engaging people like this.
What's so exhausting about math? Words are often not enough without some equations to see where things break down.
by dkfenger
Tue Jan 15, 2013 9:18 pm
Forum: News
Topic: Mach Effect progress
Replies: 2707
Views: 1466348

For purposes of argument, the t=0 and t=1s frames can be treated as two separate inertial frames. I was not trying to calculate the KE in the craft's frame, but in an inertial frame in which the craft's velocity at t=0 was specified. I think I've actually served to prove GIT's argument more than chr...