Gyroscopic effects
in [Motorcycles]
|
From: Beav on 9 Jul 2010 17:57 "?" <breoganmacbrath(a)yahoo.com> wrote in message news:d18a8adf-8d9c-4080-adf1-e56d942decb7(a)p22g2000pre.googlegroups.com... > On Jul 9, 2:10 am, CindiK <cindi.k...(a)gmail.com> wrote: > >> I know the angular momentum of the driveshaft in shaft-driven bikes >> makes it impossible for them to wheelie. > > Anything that small in diameter has *no* significant angular momentum. Hook, line, sinker, basket and a copy of "Angling Times" -- Beav
From: Beav on 9 Jul 2010 17:59 "Bob Myers" <nospamplease(a)address.invalid> wrote in message news:i17mub$88u$1(a)usenet01.boi.hp.com... > ? wrote: >> On Jul 9, 2:10 am, CindiK <cindi.k...(a)gmail.com> wrote: >> >>> I know the angular momentum of the driveshaft in shaft-driven bikes >>> makes it impossible for them to wheelie. >> >> Anything that small in diameter has *no* significant angular momentum. > > Wow, Cindi, you snagged a big one! That's "Big one" in a "Very small one" kind of way. How pleasing to see> > our leading Self-Proclaimed-Expert-On-Everything-Troll caught > like that. I was somewhat surprised too, although I really shouldn't have been. -- Beav
From: Beav on 9 Jul 2010 17:59 "S'mee" <stevenkeith2(a)hotmail.com> wrote in message news:d7328402-bb74-4c1f-820f-053e876a250f(a)n20g2000prc.googlegroups.com... > On Jul 9, 3:10 am, CindiK <cindi.k...(a)gmail.com> wrote: >> On Jul 8, 10:26 pm, sean_q_ <nos...(a)no.spam> wrote: >> >> >> >> >> >> > S'mee brought this up in another topic, but since >> > it's likely to get buried there I thought it deserved >> > a thread of its own. >> >> > Of course as a spinning object a motorcycle wheel is >> > subject to gyroscopic effects. The question is, how much, >> > and are they significant? >> >> > I can think of two gyro effects to consider: >> >> > (A) Because a bike leans in a turn, its wheels rotate >> > (or pivot) about a horizontal axis through the contact patch. >> >> > (B) In a curve, the wheels also rotate about an axis >> > vertical to the road surface. If you enter a turn northbound >> > and come out heading east, both your wheels have been rotated >> > 90 degrees to the right. >> >> > I'm pretty sure everyone here has at one time or another held >> > a spinning toy gyroscope in their hand, given it a sudden >> > twist and felt the "strange" reactive force. However, >> > on a moving motorcycle changes don't happen that abruptly. >> > The faster the bike (ie, the higher the rotational inertia >> > of the wheels, which means the higher the potential for >> > gyro effects), the more gradual the turns. >> >> > Well I don't have any metrics. My guess is that type (A) isn't >> > all that significant, especially for me. My chicken strips are >> > probably as pristine as the day the tire was made (I ride for >> > pleasure, not because I've something to prove). >> >> > Type (B) causes a precessional torque on the wheel through >> > a horizontal axis tending to force it back to the vertical. >> > This can be demonstrated using the Right-Hand Rule >> > on a left hand turn (the easiest case because all rotations >> > are clockwise): >> >> > Point your right index finger away from you (the direction >> > of travel) with your thumb pointing straight up. Your 2nd >> > (long) finger points to the left, representing the axle(s), >> > the axis of wheel spin. The Observer's POV is the place >> > on your palm where these 3 fingers "meet". >> >> > The Observer (a fictional construct for purposes of clarity) >> > looks along your long finger and sees the wheel spinning >> > clockwise. Then he looks upwards along your thumb and sees >> > the wheel *turning* clockwise. Ie, to the left from >> > the rider's POV. According the Right-Hand Rule, >> > the precessional gyroscopic torque acts on the wheel to rotate >> > it clockwise about the axis represented by your index finger, >> > resisting the force acting to lean the wheel over to the left. >> > Steer to the right and the same gyro effect resists -- not >> > the lean itself, but the rotation into leaning that direction >> > as well. >> >> > BTW I just did a quick test and verified the above, using >> > the handiest "gyroscope" I could lay hands on -- in this case >> > an electric fan (it's been a hot day here). >> >> > Again, is this effect strong enough to be significant? >> > I don't know. If anyone does I'd appreciate them >> > commenting on it. >> >> > SQ >> >> I know the angular momentum of the driveshaft in shaft-driven bikes >> makes it impossible for them to wheelie. > > Only in Oz does this not happen. And NZ too. -- Beav
From: BryanUT on 9 Jul 2010 18:41 On Jul 9, 1:28 pm, "tomor...(a)erols.com" <tomorrowaterolsdot...(a)yahoo.com> wrote: > On Jul 9, 3:15 pm, Henry <9-11tr...(a)experts.org> wrote: > > > > > tomor...(a)erols.com wrote: > > > On Jul 9, 10:36 am, Henry <9-11tr...(a)experts.org> wrote: > > >> tomor...(a)erols.com wrote: > > >>> Yes, but it is vintage, classic, succinct, and comfortingly familiar > > >>> reeky traditional bullshit! > > >> Unlike your and twitbull's claim > > > Oh wow, you're so embarrassed by what you've said that you > > had to censor it. Here's what you and twitbull believe. And > > yes, it's very, very wrong. > > > "Left to it's [sic] own devices, a non-sidecar bike will fall > > right over. And this is equally true whether said bike is moving > > or at rest." That right there is some brand new reeky bullshit! <g> > > > > I'd much rather be lumped in with Pete and his positions - even when > > > doing so is as nonsensical as you doing so above > > > The nonsense is yours and twit's, Tim. Like everyone but you > > and twitbull, I understand that a moving bike will most definitely > > not fall right over just as quickly as a stationary bike. Since > > you believe that, you must also believe that all the people who've > > seen riderless bikes roll along for considerable distances are > > delusional, and all the videos showing the same thing are faked. > > That's incredibly silly. > > No, what's silly is that you waste so much time making up stuff like > this to "respond" to. While you are feeling all intellectually > superior, well, everyone else knows what reaction they are having. Proof gyroscopic effects don't work: http://bitsandpieces.us/wp-content/uploads/2010/07/imagesbike-riding.gif
From: Twibil on 9 Jul 2010 18:57
On Jul 9, 2:57 pm, "Beav" <beavis.origi...(a)ntlwoxorld.com> wrote: > > > >> I know the angular momentum of the driveshaft in shaft-driven bikes > >> makes it impossible for them to wheelie. > > > Anything that small in diameter has *no* significant angular momentum. > > Hook, line, sinker, basket and a copy of "Angling Times" Well natch! His compulsion to appear knowledgable about motorcycles and his utter lack of humor combine to make him a first-class sucker for this sort of thing. Kudos to Cindi. |