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Ratliff
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« on: June 01, 2008, 08:37:22 PM » |
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Performance spreadsheet showed potential top speed of over 950 mph with mile average of over 880 mph.
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« Last Edit: June 02, 2008, 08:59:18 AM by Ratliff »
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Ratliff
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« Reply #1 on: June 01, 2008, 08:41:37 PM » |
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Discussion of design issues (pages 1 and 2)
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Ratliff
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« Reply #2 on: June 01, 2008, 08:52:38 PM » |
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Discussion of design issues (page 3)
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Ratliff
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« Reply #3 on: June 01, 2008, 08:55:07 PM » |
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Discussion of design issues (page 4)
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Dynoroom
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« Reply #4 on: June 01, 2008, 10:55:05 PM » |
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As Dolan would say..............
Hypothetrical cars set hypothetrical records.
Geesh I can't believe I just did that..........
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Milwaukee Midget
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Maximum Cram
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« Reply #5 on: June 01, 2008, 11:00:44 PM » |
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I don't think I'd want to be anywhere near a boiler that produced enough steam to propel ANYTHING to 880 mph.
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Ratliff
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« Reply #6 on: June 02, 2008, 12:50:56 AM » |
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I don't think I'd want to be anywhere near a boiler that produced enough steam to propel ANYTHING to 880 mph.
No boilers involved in the car itself. The tanks in the car would just be storage tanks. The water would be heated externally in a separate boiler then pumped into the car. Maximum operating pressures would be around 400 psi. |
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Rick Byrnes
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« Reply #7 on: June 02, 2008, 09:12:12 AM » |
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As Dolan would say..............
Hypothetrical cars set hypothetrical records.
Geesh I can't believe I just did that..........
AWWWW you miss him too |
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Rick
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Ratliff
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« Reply #8 on: June 02, 2008, 09:18:47 AM » |
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As Dolan would say..............
Hypothetrical cars set hypothetrical records.
Geesh I can't believe I just did that..........
Yeah, just like that hypothetical 500 mph record Doug Herbert is going to set. |
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Ratliff
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« Reply #9 on: June 02, 2008, 01:02:45 PM » |
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I don't think I'd want to be anywhere near a boiler that produced enough steam to propel ANYTHING to 880 mph.
http://www.steamcar.co.uk/If you want to see a steam car that not only has boilers but will be operating at much higher pressures than a steam rocket car, there will be one at this year's Speedweek. |
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Blue
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« Reply #10 on: June 02, 2008, 05:47:02 PM » |
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The 21% empty weight fraction and the attending ~10% structural fraction for a 1500 to 2000 psf vehicle are more than a factor of 2 away from being rational. This is a difficulty that I have run into with a lot of the people "designing" ALSR cars. Stresses are factors of 4 to 6 greater than any wheel driven car, 10X for Mach 2. Think about that factor of 10 very carefully. The design database of supersonic-at-sea-level capable aircraft and missiles provides plenty of structural weight and design guidance that simply cannot be ignored. If anyone wants to pencil out something like this, a 1000 mph FIA record requires a 35 to 40% structural mass fraction with advanced materials, straight load paths, and good structural design. Poor design or heavy materials can raise this to 60 to 75%. Note that the "structural" mass fraction does not include the engine. For reference, the structural fraction of our current project is nearly 60% due to the use of mild steel and a far-from-optimum structural layout. Thrust SSC was about 50%. 10% is irrational.  |
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"Doing the same thing as everyone else insures the same result", Shawn Fischer
"Extraordinary ideas do not come from ordinary thinking", Dan Bond
"Don't compromise, optimize", Eric Ahlstrom
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Ratliff
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« Reply #11 on: June 02, 2008, 06:30:25 PM » |
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The 21% empty weight fraction and the attending ~10% structural fraction for a 1500 to 2000 psf vehicle are more than a factor of 2 away from being rational. This is a difficulty that I have run into with a lot of the people "designing" ALSR cars. Stresses are factors of 4 to 6 greater than any wheel driven car, 10X for Mach 2. Think about that factor of 10 very carefully. The design database of supersonic-at-sea-level capable aircraft and missiles provides plenty of structural weight and design guidance that simply cannot be ignored. If anyone wants to pencil out something like this, a 1000 mph FIA record requires a 35 to 40% structural mass fraction with advanced materials, straight load paths, and good structural design. Poor design or heavy materials can raise this to 60 to 75%. Note that the "structural" mass fraction does not include the engine. For reference, the structural fraction of our current project is nearly 60% due to the use of mild steel and a far-from-optimum structural layout. Thrust SSC was about 50%. 10% is irrational. Craig Farnsworth, brother of Blue Flame co-builder Pete Farnsworth, is a missile engineer. Steam rockets operate in the 250 to 400 psi range. When one DOES THE MATH and examines various tank configurations, a 4,000 pound empty weight car with sufficient volume to hold 13,000 pounds of water may very well be feasible. |
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« Last Edit: June 02, 2008, 06:55:16 PM by Ratliff »
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Ratliff
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« Reply #12 on: June 02, 2008, 06:37:31 PM » |
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Page 2
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Ratliff
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« Reply #13 on: June 02, 2008, 06:50:47 PM » |
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Page 3
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Ratliff
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« Reply #14 on: June 02, 2008, 07:50:27 PM » |
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Page 4
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