DoctorEvo

Funding for manned spaceflight is still there. COTS and CCDev are still on. We\'re still paying to keep the ISS manned and running. SLS development is written into the budget. Furthermore, planetary missions usually take YEARS. New Horizons and Juno are both more than another Presidential term away from their destinations. The Mars Science Rover is on the pad as we speak, and is designed to last for another three years. If NASA\'s recent efforts in the post-Constellation-cancellation period are any indication, temporary funding cuts are not enough to stop them from making plans and preparing for the deed when the time is right. By the time the next spaceflight-friendly President signs more funding to them again, I\'m sure they\'ll have a handful of planetary missions ready to go just as soon as the checks can be signed.

Not even close. To be fair, the majority of NASA\'s efforts are in Earth orbit, including ALL manned exploration thus far (well, Apollo was a grey area), and in the grand scheme of things, planetary exploration is but a fraction of what NASA is up to. That said, it\'s not good news. A cut is a cut, and Obama has not been the friendliest to NASA\'s budget.

Frankly, I\'m sorry I ever did. It was only a SIDE NOTE, and only related tangentially to the 'stalling out' concept that people were discussing. Other than that, it isn\'t really related to the topic. Though, I suppose you\'d have a better chance surviving jumping out of a slow&low-flying AN-2 than most other aircraft... though you\'d STILL have a FAR better chance of surviving if you stayed in your seat. The 2-32 is not a motor glider. All motorized derivatives of it stall at MUCH higher speeds (50-70 MPH) owing to the additional weight. As a general rule, an engine adds at least as much weight to a glider as a passenger does, and with it comes a shift in certain v-speeds (stall speeds, best glide speed, minimum sink, basically anything that occurs at a fixed AOA will happen at a different speed). Very true. The 2-33 is the slowest glider I\'ve ever flown. Newer aircraft are usually faster on both ends of the spectrum. Weight does not affect glide ratio. It DOES, however, affect the SPEED at which you will achieve best glide. That\'s peculiar. It SHOULD cause an 11% drop in stall speed. Then again, most airplanes only use one 'quoted' (rather, 'marked') stall speed, measured at gross weight, despite the fact that normal stall speed is often as much as 20% less than this. It does, but not by itself. Wing loading is more scalable, though on top of that the AN-2 also has a very high Clmax going for it as well owing to its slats. You\'re STILL on about that? How do you not realize that NOBODY DISAGREES WITH YOU ON THIS?! You\'re literally trying to argue a point to which there is NO opposition. Nobody is trying to suggest that it\'s possible to make such a leap. Nobody is trying to argue that jumping out of an airplane is more survivable than staying in your seat. So can we stop bringing it up? (And, once again, mach 0.6 is an unrealistic number for low-altitude flight. 200 knots/M0.3 is much more realistic for a jet, or M0.15 for a \'typical\' piston aircraft). I\'m not sure that\'s completely cogent... I think 10,000G for 1 millisecond would be likened to being hit by a train moving at 200 MPH. Even for instantaneous events, some level of cushioning is preferable (crumple zones and whatnot). Frankly, the only issue where that is even remotely relevant isn\'t being argued by anyone but you. Do you have an imaginary nemesis that keeps countering the claim that jumping from a plane with 200 m/s of delta-V isn\'t possible? Because none of us are, yet you keep bringing it up - as the very center of your argument, no less. The only parts we\'re correcting you on are the areas where you actually ARE wrong - the idea that 500ms accelerations are not effectively instantaneous, the idea that the AN-2 is somehow not a good (and safe) airplane for slow flight, the notion that airplanes usually fly at mach 0.6 close to the ground... all blatantly wrong. (Yet you still stand by them in the face of quantitative facts proving the opposite... ???) But when it comes to the very answer to the question of this thread, WE ALL AGREE WITH YOU. How do you not understand this? But gliders AREN\'T designed for that flight regime! They AREN\'T designed with STOL in mind!! They\'re designed to GLIDE. Their relatively low stall speeds are merely an artifact of being built to achieve low minimum-sink rates. The AN-2, on the other hand, was designed with STOL in mind (much like the Storch you mentioned earlier), employing tremendous wing area, leading-edge slats, large control surfaces, an upright windshield with excellent visibility... IT IS BUILT TO GO SLOW, and it DOES GO SLOW. Yet you keep irrationally claiming it is not good for this. I get the feeling you just hate the AN-2 because it\'s ugly.

I think my MacBook is coming up on four years old now.

I never suggested it did. Re-read my posts. I AGREE WITH YOU - MAKING A SURVIVABLE JUMP IS IMPOSSIBLE. But surviving a 40g crash, presuming you were buckled in with the tray table up, etc. etc. is very likely. People don\'t die from sub-20g instantaneous accelerations. Col. Stapp proved that. So I guess the only thing I would ask those people is, 'why didn\'t you wear your seatbelt?' Only your chances of surviving a 40g crash ARE MUCH BETTER THAN 50%. In a F-1 car, with all the safety restraints it includes, even 100g crashes result in nearly 50% survival rates, though you will almost certainly be seriously injured. Tell you what, YOU go find a \'modern motor glider\' that stalls at less than 30 mph/26 knots and get back to us on that. The AN-2 was DESIGNED to have benign stall characteristics, using a ridiculously low wing loading and massive leading-edge slats. Hence the incredible ability to 'parachute' to the ground in deep stall as I mentioned in the first place.... : (And I\'m not 'just a flight sim guy.')

If you are properly restrained, such serious brain trauma will not occur. Such trauma typically occurs from things such as, say, hitting your head on the dash or on the ground after a long fall. Furthermore, crash test dummies are equipped with 100 G (that\'s ONE HUNDRED, not fifty) accelerometers in their head that are usually used to determine ultimately whether the crash was fatal or not. But I DO fly the Cessna 172, among others. And the Schweizer 2-33 (a slow, 1930s-designed glider) which I first learned to fly in stalled faster than the AN-2 does, so I\'m pretty sure your presumption that motor gliders (which are obviously heavier) can fly even slower is incorrect. I\'m not at odds with you on this. IF YOU JUMP, YOU WILL DIE. I\'m not denying that. My remark that 50 Gs is survivable was not meant to imply the human body is capable of JUMPING at 50 Gs. Half a second IS considered an instantaneous event, though. Most of John P. Stapp\'s rocket sled tests involved velocities exceeding 400 MPH. With some simple, elementary school math, you\'ll see that his INSTANTANEOUS tests - which ranged from 20 to over 45 Gs - were all half a second or longer. NON-instantaneous accelerations are those which are long enough to incapacitate simply due to a lack of circulation. Thus, about 2-3 seconds is where things go from instantaneous to sustained. Well I already stated that the common threshold at which crashes, etc. are deemed fatal is at least twice the acceleration that we\'re discussing, so that\'s a fairly large margin already. On top of that, properly-restrained racecar drivers have survived accelerations exceeding 100 Gs on many occasions, including at least one case of over 200 Gs. I\'m trying to...

I hope you\'re joking. The AN-2 was produced in truly MASSIVE numbers. For an aircraft as numerous as it is, 365 hull-loss accidents is not bad at all. I just did a quick query of NTSB hull-loss accident reports for the Cessna 172, and I count over four hundred in JUST THE LAST TWENTY YEARS, with even more fatalities. It may be ugly, but it\'s a fine-flying airplane, and the fact that it flies so darned slow means it\'s less likely to kill you than just about anything else out there. 50 Gs for half a second is not likely to result in death. Severe contusions, certainly; broken bones, quite possibly; but unless you forgot to buckle up, death is improbable. I never implied such a jump was possible. But just so we\'re totally clear, NO, YOU WOULD NOT SURVIVE JUMPING OUT OF AN AIRPLANE JUST PRIOR TO CRASHING. Such a notion is so utterly absurd, I felt it didn\'t even need to be said. And another thing, planes don\'t fly at mach 0.6 close to the ground unless they\'re fighter jets with the afterburners lit. Realistically, you\'re looking at closer to mach 0.25 for a typical airliner at low altitude in landing configuration (which pilots will try to achieve prior to crashing if at all possible), or 0.35 for one in cruise configuration. IT WAS A SIDE NOTE HENCE THE WORDS 'As a side note' SHEESH ???

You can\'t be serious. You\'re wrong there. Instantaneous accelerations of over 100 Gs have been survived before, and in crash-testing fields a 50 G crash is commonly considered to be moderately harmful, but not fatal. Or you could, y\'know, just land instead... As a side note, the Antonov AN-2\'s emergency procedures includes a protocol emergency landing that involves placing the airplane in deep-stall and 'parachuting' to the ground. It would almost certainly wreck the airplane, but with that much wing area, I guess you\'d actually have a decent chance of surviving it.

Yours is a solid candidate for most mesmerizing, I\'ll tell you that much.

It\'s not an issue at all. You don\'t NEED your exhaust jet to be greater than your final velocity if your mass fraction is greater than 2.72. Of course, mine will be even greater - around 10 or so... *edit* Alright, I did a little research and crunched a few numbers as sort of a reality check. I decided that, based on available materials and the scale of other investments I\'d need to get my rocket off the ground, something a little better than fiberglass would be ideal. So, with a new fiber in mind, I found the material properties, and calculated a baseline pressure figure by assuming 1000 feet of 80-lb fiber wound around a 2-liter bottle (realistically, I\'d probably use a shorter length of heavier fiber, still achieving similar figures). Based on these figures I determined I could wind a 2000-PSI body weighing about 100g 50g/liter, for about $60/liter. By comparison to the current world altitude record holder, the carbon-wrapped X-10, this is VERY favorable (then again, it includes ONLY body weight and ignores the weight of the camera, altimeter, and recovery system the X-10 carried). Yet still, pushing these numbers further, it appears reaching the sound barrier is going to be more challenging than I initially thought. I took this pressure value and cut it in half to roughly account for pressure loss during expansion (realistically the average would probably be less than that, but this is only a reality-check), and then used the Bernoulli equation to estimate a conservative average water jet velocity. This came out to about 117.4 m/s. I then plugged it into Tsiolkovsky\'s trusty rocket equation to determine what kind of mass fraction I\'d need to get a minimum amount of delta-V (Realistically, I think I\'ll need AT LEAST 400 m/s to account for drag, but that remains to-be-determined). Using 500 m/s I got an impossible 70:1 mass fraction, so I of course jumped to the absolute (unrealistic) minimum - 343 m/s, or exactly mach 1. Here I found that 18.5:1 would be necessary. Given that water rockets are typically filled less than half full for optimal balance between compressed air and mass fraction, this is much higher than the ~8:1 ratio the current concept would realistically achieve. With said ratio and the previous water jet figure, my rocket would theoretically achieve 244 m/s of delta-V - impressive, but not nearly fast enough. Re-figuring the exhaust velocity for the full 2000 PSI and the (again, unrealistic) low-ball delta-V figure of 343 m/s, I finally achieved an ~8:1 ratio, but unless I use liquid methane to pressurize my rocket, I\'m not going to be able to maintain that kind of constant pressure throughout my boost phase. Furthermore, I ran some numbers for drag and determined that, using a Cd of ~2 at mach 1 (note to self - reference this value against spitzer bullet ballistic coefficients as a reality check) and a sea-level air density, I determined approximately 250 lbs of thrust would be required to penetrate the sound barrier (ideally, you\'d want at least double that to minimize losses) with a 4-inch-wide rocket (i.e. 2-liter bottles). At 1000 PSI, this shouldn\'t be terribly difficult to achieve with larger nozzles, though using a taller, thinner rocket would still be prudent (a rocket with half the diameter, for instance, would suffer only about 1/4 the drag). I\'m in no way about to write off the idea as impossible at this point; I don\'t really have any stronger materials to turn to, but there\'s still lots of optimization to be done - finding the ideal compromise between empty weight (mass fraction) and pressure (specific impulse), performing a more realistic estimate of gas expansion... and of course, considering the option of using multiple stages. *edit2* I found a simple error in my initial container-weight calculations (I forgot to divide the weight of my two-liter wound bottle by two to find grams-per-liter), which puts my mass fraction at a much more promising ~16:1. I\'m still not QUITE there, but it\'s darned close, and I\'m now very confident that a bit of optimization will tip the scales.

I did it once in Orbiter. The Russians did it a dozens of times. It\'s possible, and while less than ideal, it\'s not particularly prohibitive, since there are naturally periods of low-velocity flight in a lunar transfer during which the plane-change may be more-efficiently done. The way to set it up in Orbiter when you wish to go from an arbitrary LEO to the Moon is to (mentally) project a line through the ascending and descending nodes out to the Moon\'s orbit, plan on intercepting the Moon at one of these points, time-accelerate until the Moon is the appropriate distance from reaching this point, then perform your TLI at the opposite node.

800 feet? PFFFT. Welcome to ten years ago. http://web.archive.org/web/20080117120905/http://www.geocities.com/wrgarage/millen.htm On a side note, I\'m thinking of trying to build the world\'s first supersonic water rocket. I still need to run some numbers to see if fiberglass has the material properties I need or not.

Wait... so you\'re saying... we ARE the China in this analogy?! (But seriously, thanks for clearing that up. I feel like the people who missed it didn\'t listen to the entire message.) The Chinese shoot the QBZ-95 now.

At first, I misunderstood your picture and thought you were suggesting harvesting Earth\'s rotational kinetic energy via tension in a space-elevator-esque tether (which, in theory, WOULD work, but would not be worth the expense from an engineering standpoint). But now that I understand what it actually IS... No, of course it wouldn\'t work. : Well, if it were possible to 'sidereally-fix' a gyro (which it isn\'t, all a gyro does is add angular momentum), I suppose that could work. But, as you mentioned, the energy yield would be pathetic unless you used absurdly large weights, and it would only be coming from the specific orbital energy of your satellite (which you had to pay for in the first place), so this idea is, needless to say, kinda pointless.

I sorta feel like the Brits will return to deck parking with the Queen Elizabeth class now that it\'s slated for CATOBAR. The biggest advantage of CATOBAR is that it consumes only a small amount of deck space for launching, and leaves considerable space for simultaneous landing or parking. The STOVL carriers often rely on using the whole deck for takeoff when loaded, so they actually frequently NEED the entire deck to launch without catapults. CATOBAR opens up a whole lot of real estate for all kinds of configurations and operations, permitting massively more frequent launch and recovery rates, and thus a higher mission-availability for aircraft operating from a single carrier. I highly doubt the Royal Navy will pass that operational capability up.