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#91
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Matt Whiting wrote in message ...
Harry K wrote: Matt Whiting wrote in message ... Ron Wanttaja wrote: It took about forty years from the date the first government-sponsored manned aerospacecraft left the atmosphere and glided down to a safe landing in the California desert to the successful flight of the first private one. If the same timescale was used for conventional airplanes, the first privately-owned aircraft would have flown in 1943. I never knew that the Wright Flyer was gummint sponsored... Matt Looks like you (and others) missed the little "if" in Ron's post. Harry K No, I didn't miss it and I doubt the others did either. The comparison was time delta of the first GOVERNMENT sponsored flight of a spacecraft to the first private one. If the same timescale was applied to conventional airplanes, you would be comparing the first GOVERNMENT sponsored flight of a conventional airplane to the first private one. Backing 40 years off of 1943 yields 1903, which is NOT when the first GOVERNMENT sponsored airplane flew successfully, so the comparison is completely invalid. Matt And if you re-read that one line starting with 'if' you will see that he never claimed that. He was saying that if conventional flight had been developed by the government it would have been 1943 before it happened. Harry K |
#92
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ISTR that there was A1P a plan to orbit an X15, using iirc a Titan rocket,
reenter, and parachute the pilot to ground. What TPS would have been used? Might such work be of value on SS2? |
#93
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On Thu, 24 Jun 2004 08:33:29 GMT, Richard Lamb
wrote: Ron Wanttaja wrote: Anyway, you do have it backwards...orbital velocity decreases with circular orbit altitude. ~25,200 FPS at 200 nm, ~10,100 FPS at geosynchronous altitude (~19320 NM). You're right about the potential energy, though. Dropping from geosynchronous altitude to ground level, you'll hit the atmosphere at over 23,000 miles per hour. And if you're an old-timer like BOb, you'll have the turn-signal flashing the entire way.... So? To catch up with the guy in front of you, you first slow down? Precisely. Think of it in terms of angular rate. If you're both in the same 90-minute equatorial orbit, you're traveling around the Earth at an angular rate of four degrees of longitude per minute. To catch up to the guy in front, you need to increase your angular rate, e.g., an orbit with a shorter period. The angular rate is inversely proportional to orbit altitude...LEO (Low Earth Orbit) satellites are at a few hundred miles and go around the Earth in 90 minutes or so, but Geosynchronous satellites are at ~19300 NM and take a full 24 hours to orbit the Earth. The velocities needed to maintain the orbit are lower, and the circumference of the orbits is longer...you're not only flying slower to start with, but the distance you have to travel for one orbit is longer. So... if your buddy is a few hundred miles ahead of you in LEO, you slow up. This lowers your average orbit altitude and decreases your orbit period. You've now got a period, say, of 88 minutes and an angular rate of 4.1 degrees a minute. Every minute, you're 0.1 degrees (roughly 6 nautical miles, in LEO) closer. You're also slightly below your buddy, but when you catch up, you increase your speed, which raises your orbit. Mind you, if your friend had been only a hundred feet in front of you, you just would have popped your little thrusters and flown directly to him. It will perturb your orbit, but would be minor compared to normal orbit maintenance maneuvers. Compare it to having to climb 10 feet in an airplane vs. 10,000 feet. You'll just tug the stick back slightly for the first case, but add power for the second. Otherwise, though, orbit mechanics is *definitely* non-intuitive to an aircraft pilot. In an airplane, we're always concerned about how far we can fly, and can easily change directions if we desire. The situation is exactly opposite in orbit... the vehicle has nearly unlimited range, but a change in compass course is prohibitively expensive. Ron Wanttaja |
#94
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On Thu, 24 Jun 2004 02:01:07 +0000, B2431 wrote:
Date: 6/23/2004 8:40 PM Central Daylight Time Message-id: Matt My computer bombed so this may go as a dup? I have thousands of hours in jet fighters breathing 100% oxy. We had all kinds of electrical stuff in cockpit(s) and aircraft. High power Radar, Radio's, etc., etc. . Big John ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~ On Wed, 23 Jun 2004 18:28:37 -0400, Matt Whiting wrote: Richard Lamb wrote: In the aftermath of the Apollo 1 fire, NASA took a year (and $75 mil) to redesign the space craft, mature their mental attitudes, and yes, did come back with a much safer vehicle. Yes, but I still wonder how anyone in their right might would use a nearly pure oxygen atmosphere in a vehicle full of humans and electrical equipment... Matt The difference is Apollo 1 was flooded with pure O2 where jet fighters push O2 from a LOX converter to a face mask. Big difference. Even then, Chuck Yeager get half his face burnt in a fire when he ejected, IIRC. AC |
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Harry K wrote:
And if you re-read that one line starting with 'if' you will see that he never claimed that. He was saying that if conventional flight had been developed by the government it would have been 1943 before it happened. Well, from Ron's later comments I don't think that is what he said or meant, but whatever.... Matt |
#96
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Ron,
No one's sneering at brilliant aerospace Columbus types like you guys Ron. But the era of expensive government-only exploration is over. Burt Rutan is Mayflower. He's trying to get the rest of us slobs over to the New World for a new life. What Burt *has* always sneered at is the lack of follow through by the government so that all this fantastic technology will trickle down to the common man. The common man is what Burt has always been about. And this always seems to lead to hard feelings by people who are entrenched in doing things the same expensive government slow-turtle way all the time that invariable always leads to the ignorant masses clamoring for cancellation of all those expensive unnecessary space missions to places we have already been. Burt Rutan is, if you like, our de facto Robin Hood of Aviation and now, Space. Most of us have dreamed all our lives of the emergence of a "Dutch East India" type company that would greatly supplant the government's stranglehold of the high seas (or rather in this case: the high altitudes.) I just didn't think I would be lucky enough to see it in my lifetime. The famed Dutch East India Company didn't invent the lateen sail or the sternpost rudder either, but their improvement of those basic concepts lead to the greatest commercial conquest the world had ever seen of the known globe. Burt does the same thing with publicly available NASA data, e.g. winglet on the vari ezie, lifting body data on Space Ship One. Enjoyed your post very much Ron, glad to see you aren't using Acme's disappearing/reappearing ink anymore, aye "Dr a.a.com." pacplyer Ron Wanttaja wrote in message . .. On Thu, 24 Jun 2004 01:06:23 -0400, Matt Whiting wrote: No, I didn't miss it and I doubt the others did either. The comparison was time delta of the first GOVERNMENT sponsored flight of a spacecraft to the first private one. If the same timescale was applied to conventional airplanes, you would be comparing the first GOVERNMENT sponsored flight of a conventional airplane to the first private one. Backing 40 years off of 1943 yields 1903, which is NOT when the first GOVERNMENT sponsored airplane flew successfully, so the comparison is completely invalid. The purpose of the comparison was merely to illustrate the time spans involved, not to try to contrast the difference between government vs. private efforts. A less controversial comparison would have been along the lines of "...it was as if no else other than the Wright brothers had been technically capable of building an airplane until 1943." Rutan's achievement is tremendous, but let's not forget, he's standing on the shoulders of giants. SpaceShipOne's success is due to Rutan's brilliant combining of today's cutting-edge technology. He probably has more computing power on his desktop than NASA had in 1960. There wasn't any wind-tunnel testing done on SpaceShipOne; it was all done on a computer. Yet, barely ten years ago, the first flight of an improved launch vehicle failed because the aerodynamic models used weren't accurate enough. That company trusted the computer model and didn't do any wind tunnel testing. The launch vehicle and satellite end up in the drink. Oops. Burt Rutan was fully aware of this instance...after all, his company built part of that rocket's structure (which was in *no* way involved in the failure). Yet, in ten short years, modeling capabilities have improved to the point where he felt confident in risking a manned flight on computational data only. Rutan did one heck of a job, but some folks in this newsgroup have used it as an excuse to sneer at the people who developed some of the technologies that made it possible. If suborbital space flight was so doggone easy, the first private space launch would have been four years after the X-15, not forty. Ron Wanttaja |
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#98
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Ron Wanttaja wrote snip
Second...and, probably more-easily overcome...there's the G-load issue. IIRC, Melville experienced about 5 Gs, maximum, during re-entry. 5 Gs from a re-entry speed of Mach 3 vs. a re-entry speed of Mach 25. Hmmmm...think we'll have to trim the size of shuttlecock tail. :-) Actually it was 6 G's Finally, we get to the heretical part of this posting: Why wings at all, for an orbital mission? Forty years ago, a few square feet of ablative heat shield was good enough to handle most manned space missions. The Russian space program has flown them continuously. You have to keep in mind the objective of Burt's program. Hitting the ground hard with frozen parachutes might be O.K. for a Ruskie government pilot, but it's just too risky for common carriage passengers; the Russians have thumped to death an otherwise successful mission crew at the last few seconds more than once. Splashing down at sea might be O.K for a U.S. military pilot, but the expense of recovery (ships etc,) and possibility of drowning are increasing the complexity of the mission. Again your government sanctioned solutions are contrary to everything Burt stands for. On SS1 Burt has dispensed with parachute heaters, window heat, heavy RCS, expensive launch facilities, ground simulators, the list goes on and on. And Rutan's endeavor cost in the ten's of millions, while the illustrious government shuttle costs two billion just to build and an additional one-hundred million per launch. Now I love the shuttle, but it's too old and just too complex to operate commercially. Burt will undoubtedly offer scaled up orbital versions that can handle pax/commercial payloads if the gov weenies and corporate CEO idiots leave him alone all the way to fruition. E.g. the Beech Starship that failed commercially is not the same as the prototype we saw flying at Mojave. Burt's is devoid of all the heavy crap that Beech loaded down the production model with, which in turn with all the gov and corporate interference ran the cost out of sight (up to bizjet prices.) Just because you want to re-use an orbital vehicle doesn't mean it has to have wings. Unless the vehicle is able to reposition itself from its landing location to launch location, you're still stuck with considerable infrastructure to recover, service, and transport the vehicle. Wings on your deorbit vehicle don't help those functions. They allow pin-point precision landings...but if you're just going to land out in the desert, does it really make a difference? If you're aloft for more than one orbit, you are not going to be able to land at your departure point until about 12 hours later. The base being in the desert is really immaterial. The purpose of a winged vehicle is that it can deorbit burn and abort into any public airport in the world. Again no recovery sites required. Again cost is low. Mojave is not maintained by Scaled or Vulcan. It is a public airport open to anyone. You do it any other way and now you have a recovery range to prepare, maintain, pay for, and at all costs reach with the vehicle. I know the purpose of a gov contractor is to run costs out of sight so these cost-saving concepts will probably be alien to you for a while. ;-) For the most part, American capsule landings were within sight of the recovery base. Isn't that accuracy enough? In sight of a multi-billion dollar aircraft carrier? Do you have any idea how much an old non-nuke recovery ship burns? What about the cost of the crew alone? How is that efficient? snip good aero stuff here By the way, NASA has "Astronauts," Russia has "Cosmonauts." We need a name for the ordinary folks who fly on SpaceShipOne: I hereby suggest "Commonauts" for those lucky SOBs who get to ride Burt's space bird. Ron Wanttaja Naa. These people are colonizing space in a much more efficient manner than the government ever could. For the first time manned space is going to be commercially viable. I would think "Colonaut" would be a much better name for them. Cheers "aye" pacplyer |
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#100
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In pacplyer wrote:
Ron Wanttaja wrote snip By the way, NASA has "Astronauts," Russia has "Cosmonauts." We need a name for the ordinary folks who fly on SpaceShipOne: I hereby suggest "Commonauts" for those lucky SOBs who get to ride Burt's space bird. Ron Wanttaja Naa. These people are colonizing space in a much more efficient manner than the government ever could. For the first time manned space is going to be commercially viable. I would think "Colonaut" would be a much better name for them. That's appropriate, because just the thought of going up in one of those things is enough to tie my colon in a knot. ---------------------------------------------------- Del Rawlins- Remove _kills_spammers_ to reply via email. Unofficial Bearhawk FAQ website: http://www.rawlinsbrothers.org/bhfaq/ |
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