jjb@sequent.UUCP (Jeff Berkowitz) (06/05/89)
In article <1989Jun4.055452.12921@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >In article <486@cybaswan.UUCP> iiit-sh@cybaswan.UUCP (Steve Hosgood) writes: >>>NASA to test a parafoil system, developed by Pioneer Aerospace, for >>>precision landings by parachute of launcher components... >> >>Wasn't this originally invented by Dr Francis Rogallo in about 1963? ... > >If I haven't got the terms mixed up, no, they are not the same thing. Henry's analysis of the difference is (as usual :-) correct. Parafoil- like designs, however, are in use both as kites and as human-carrying gliders; the latter are popular especially in Europe. Their advantage over hang gliders is that the lack of airframe makes them easy to fold into a backpack and carry; they have a relatively poor glide, however, and appear to be difficult for humans to flare (and therefore land) safely. I'd like to advance the idea of Rogallo or parawing vehicles for crew escape from low earth orbit. There are several (unlikely) failure modes which leave the shuttle "stuck" in orbit. If you thought the Challenger accident was tough to stomach, imagine the spectre of a shuttle crew dying in orbit. Could an escape vehicle consisting of a small solid fuel rocket (for deceleration burn) and collapsible wing be used in this situation? After the burn you would be "dropping like a stone" toward incineration in the atmosphere. The only solution would be "skipping" off the atmosphere to lose velocity (an idea proposed as early as WWII). With a small computerized guidance system, might it be possible to do this safely? My knowledge of mach 17 aerodynamics at the edge of space is, mmm, not quite up to answering this (to say the least). As people (of whatever nationality) make increasing use of L.E.O., seems to me a system for getting them back down in an emergency will assume increasing importance. (And guess what? I didn't even talk to a patent lawyer before I posted this! :-). Another ex-hang glider pilot... -- Jeff Berkowitz N6QOM uunet!sequent!jjb Sequent Computer Systems Custom Systems Group
henry@utzoo.uucp (Henry Spencer) (06/05/89)
In article <16879@sequent.UUCP> jjb@sequent.UUCP (Jeff Berkowitz) writes: >I'd like to advance the idea of Rogallo or parawing vehicles for crew >escape from low earth orbit... >Could an escape vehicle consisting of a small solid fuel rocket (for >deceleration burn) and collapsible wing be used in this situation? There have been a number of proposals for crew escape from low orbit. One almost inevitably ends up needing a heatshield of some sort, though, after which a conventional parachute is usually preferred. (The "almost" is because I recall seeing one scheme using a rather unusual parachute to do most of the declerating at very high altitude, high enough to keep the heat loads down to what a conventional spacesuit could handle.) There really doesn't seem to be a lot of advantage in using a wing for this purpose. The obvious ways of building a collapsible wing won't stand up to reentry heat. -- You *can* understand sendmail, | Henry Spencer at U of Toronto Zoology but it's not worth it. -Collyer| uunet!attcan!utzoo!henry henry@zoo.toronto.edu
tneale@aeras.UUCP (Tom Neale) (06/07/89)
In article <16879@sequent.UUCP> jjb@sequent.UUCP (Jeff Berkowitz) writes: >Henry's analysis of the difference is (as usual :-) correct. Parafoil- >like designs, however, are in use both as kites and as human-carrying >gliders; the latter are popular especially in Europe. Their advantage >over hang gliders is that the lack of airframe makes them easy to fold >into a backpack and carry; they have a relatively poor glide, however, >and appear to be difficult for humans to flare (and therefore land) safely. On the contrary, ram air (squares as we call them) parachutes are quite the norm in sport parachuting today. Their glide is a respectible 3:1 or better (great when compared to a round parachute at <0.4:1). Forward speeds are 20-30 MPH for most models. Further, they are quite easy to flare and land safely. I have over 1300 square jumps with no problems and landings are normally tippy-toe soft. :-) This is no longer shuttle related but I felt compelled to clear up any mis-information about a subject near and dear to my heart. -- Blue skies, | ...sun!aeras!tneale | | in flight: N2103Q | The hurrieder I go Tom Neale | in freefall: D8049 | the behinder I get. | via the ether: WA1YUB |