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Old 02-08-2012, 11:29 AM   #145 (permalink)
Ken Fry
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Quote:
Originally Posted by sendler View Post
The tail fin can only push the rear of the bike with the wind but it is forcing the rear tire to go sideways in order for anything to happen.
Because the rear wheel cannot move sideways easily, instead the steering head will be pushed into the wind, cancelling (to some extent) the bike's self correction.

I quickly scanned the web but could not find Wagner's justification for the rudder option. But if I recall from having read it years ago, I think it was intended mainly for roll control assist. The fact that it is rarely seen, and is not seen as an option for the Monotracer, suggests that it has little value. I haven't seen a close up, but for it to be of any net gain, it would have to be able to weather cock, so that at very low speeds with a near direct crosswind, it does not simply tend to roll the bike over. At higher speeds, the entire thing would need to weather cock so that it is not stalled when the apparent wind angle is greater than about 12 degrees... if you are using it for roll control, then you'd want to be well away from the stall regime all the time.

In aircraft, stabilators (combined horizontal stabilizer and elevator) are not uncommon. Combined vertical stabilizers and rudders are very uncommon -- but for a motorcycle, you'd need something of this nature, for the many conditions when you don't want something high up trying to push you over. Then, unless the intention is to dramatically increase driver workload, the thing would need to be under computer control to interpret driver intention.

Given that $80,000 for a motorcycle is decidedly rich guy toy territory, if the rudder had any beneficial effect it would have been purchased by many customers. I'd expect it to have no useful effect, (as well as the obvious negative effect of trying to roll the bike in the wrong direction in a cross wind) and market response seems to support that.
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