A paradoxical thought experiment
in [Motorcycles]
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From: Mark Olson on 8 Jul 2010 14:05 Twibil wrote: > Note: Left to it's own devices, a non-sidecar bike will fall right > over. And this is equally true whether said bike is moving or at rest. > > It's only the kickstand when at rest, or the rider's constant > corrections when moving, that keep it upright. A riderless bike will happily stay upright so long as it is moving. Put a throttle lock on it and give it open space and it will go until it runs out of gas.
From: sean_q_ on 8 Jul 2010 14:21 Vito wrote: > | Make a hard left turn; the chair lifts because it lacks > | enough weight to keep the bike from leaning into the turn. > > I don't think so. A bike must be forced to lean, either by 'body english' > or counter-steering. Instead of "Make a hard left turn" perhaps I should have said, "apply clockwise torque to the steering" which, on a non-sidecar bike is the countersteering action to initiate a left turn. With a sidecar is present, but of negligible weight, the bike should behave "normally". That is, lean (and turn) left. Of course in the Real World a sidecar has significant mass. Its weight is what prevents the above; up to a limit, anyway. Beyond that, the chair lifts. Now where did my Paradox get to? I know I left it lying around here somewhere... SQ
From: The Older Gentleman on 8 Jul 2010 14:22 J. Clarke <jclarke.usenet(a)cox.net> wrote: > On 7/8/2010 4:26 AM, TOG(a)Toil wrote: > > > > I'm sure the US has, but that was the only one I could remember. I > > suppose you could say that the Northrop whatever-it-was and the B2 > > bomber are lifting bodies of a kind. > > Nope, they're flying wings, the opposite of a lifting body. Heh. Wings fly, lifting bodies don't? ;-) By the way, > the B2 is a "Northrop whatever-it-was", sixth in the line of > development--there was the small prototype, a 1/3 scale development > mule, the propeller driven bomber, the rocket fighter, the jet bomber, > then a long hiatus, then the B2. I didn't know about the others, and I thought I knew a bit about aircraft. Was the original tech pinched from Horten, then? > > As for the lifting bodies, they were all testing ideas for wingless > reentry vehicles. There've been at least 7 built in the US and it would > be surprising if the Russians hadn't fiddled with them as well. A > lifting body design was considered for the Shuttle but that > configuration couldn't meet all the requirements that were placed on it > by the planners, most of which capabilities have never been used. Interesting. > <snip> > > However, there was not enough thrust in all Christendom to fix the F-111B. Hah. And our government cancelled the TSR2 to buy that useless device instead. -- BMW K1100LT Ducati 750SS Honda CB400F Triumph Street Triple Suzuki TS250ER GN250 Damn, back to six bikes! Try Googling before asking a damn silly question. chateau dot murray at idnet dot com
From: Bob Myers on 8 Jul 2010 14:27 ? wrote: > On Jul 7, 2:14 pm, sean_q_ <nos...(a)no.spam> wrote: > >> Isn't there some kind of plane with no wings? Where the fuselage >> is designed to create its own lift? > > The fuselage of any conventional aircraft produces lift. Generally not unless it's at a fairly large angle of attack. The question specifically referred to a fuselage DESIGNED to contribute significant lift, presumably in normal flight. Most designs for conventional aircraft fuselages do NOT produce significant lift under those conditions. Hence, we're specifically talking about that fairly small group of aircraft designs referred to as "lifting bodies." Do try to keep up, OK? > As I recall, general aviation aircraft may not have a stall speed > above about 50 or 60 knots, according to FAA regulations. (A) Who said anything about "GA" aircraft? (B) There's no such category as "general aviation aircraft" in the first place. Airplane categories for type certification include those such as "normal," "utility," "acrobatic," "commuter," "transport," etc.. For the smaller normal/utility categories, the minimum steady flight speed or "stall speed" must be at least 61 knots CAS. (C) The whole discussion of FAA regulations re stall speed for any of these categories is irrelevant, since no one has ever even attempted to get a type certificate for a lifting-body design in any of these categories. Lifting bodies have been limited to experimental/military designs. So as usual, you contribute nothing of value here. How surprising. Bob M.
From: Henry on 8 Jul 2010 14:37
Twitbull imagined: > On Jul 8, 4:18 am, "Vito" <v...(a)cfl.rr.com> wrote: >> I don't think so. A bike must be forced to lean, either by 'body english' >> or counter-steering. > Oh dear. > Note: Left to it's own devices, a non-sidecar bike will fall right > over. And this is equally true whether said bike is moving or at rest. Actually, that's dead wrong. An upright, moving bike will continue to travel upright until friction and/or air resistance reduce its speed enough that it falls over. Even just 10-15mph is enough to keep it upright. It's impressive how little you know and understand about many very basic concepts... -- "Condemnation without investigation is the height of ignorance." -- Albert Einstein. http://911research.wtc7.net http://www.journalof911studies.com/ http://www.ae911truth.org |