Quote:
Originally Posted by JSeery
My experience has been that anything with rear steering is somewhat difficult to steer, think fork lift.
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J...…..You bring-up an interesting subject that just so happens, I know a little bit about. There is a very real reason for this unstable-steering phenomenon when moving forward in any vehicle with this "tail-wheel" steering configuration. The 'unstable' steering tendencies in a vehicle with this configuration is merely a result of physics, and if I had to guess, it probably falls under one of Mr. Newton's Laws.
Anyway, did y'all catch that "tail-wheel" thing I mentioned just above? This is the same phenomenon which pilots that have experience in taildraggers (like a DC-3 or a Piper Cub) know all about. Any time a tail-wheel-equipped airplane is moving forward with any speed at all while on the ground, and especially while landing or taking-off, the aircraft is susceptible to what is known as a "ground loop". A ground loop is the tendency for the tail of a tail-wheel-equipped airplane to swing either left or right, unstably, unless the pilot is vigilant and prepared to 'catch' and arrest the un-commanded swing with opposite rudder inputs. A taildragger pilot is always busy 'dancing' on the rudder pedals with small (or large) inputs when taking-off or landing. If he's not ahead of the airplane with the slightest deviation of the tail by correcting the beginnings of a swing with rudder input, the tail will gain momentum as it is allowed to swing farther and farther out of line with the desired direction of travel. Depending on the airplane involved, speed, possible crosswinds, and maybe even water on the runway, in the blink of an eye the tail can swing fiercely-around to a point that the airplane can be sliding sideways (or more), and even including leaning over onto the downstream wing tip causing damage there. The main landing gear can be damaged, or even sheared off of the aircraft. It CAN be a violent ride. Ground loops virtually NEVER occur in a nosewheel-equipped airplane. Watch how busy the pilot's feet stay on the rudder pedals during the last 25 seconds or so of this video while landing this small Luscombe taildragger....link below!
https://www.youtube.com/watch?v=faBwl8mEkc4
The 'physics' reason for this phenomenon occurring in vehicles (and airplanes) steering from the rear, like Will D's 3-wheeled terror, is because when traveling forward, the CG (center of gravity) is located BEHIND the two main (non-steerable) wheels. Once that CG really gets started on it's journey in a direction perpendicular to the direction the vehicle is traveling, momentum (remember Newton) builds to a point that the sideways movement (inertia) becomes too much to overcome....and you're destined for one of the rides of your life.
In the case of your childhood tricycle, forklifts DRIVEN IN REVERSE, and nosewheel-equipped airplanes, the CG is located IN FRONT of the two main wheels. Physics dictates that the CG of any moving vehicle is always trying to get in FRONT of, or to lead the two main wheels in the direction of travel. In any nosewheel-steering vehicle, the CG is ALWAYS in front of the two main (non-steering) wheels. Otherwise, if the CG was behind the main wheels, the vehicle (think airplane) would tilt back onto it's butt.
So, if Will D wants to turn the seat around in that racer and go the opposite direction, that thing ought to haul-buttsky STRAIGHT as an arrow down that hill! DD
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