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Side-wind resistant streamliner. |
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Balor
Visitor (new) Joined: 25 January 2017 Status: Offline Points: 154 |
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Ok... I think I've solved the wind steer problem given positive trail for good.
https://imgur.com/a/ytuaU50 If you flip the VPS steering (like that on Horn's bike) upside down, instead of getting virtual positive offset in turns (due to virtual steering axis inclination), you get virtual negative offset, a ton of return to center force yet close to zero 'trail' in conventional sense - as seen from the side, hence SIDE force has no leverage to steer you, and when you brake in a turn the wheel will try to self-right instead of going to full lock. The problem is, you need a ball joint with rigid connection to the frame somewhere *inside* the wheel... or above it and you still get what amounts to a head tube and the effect of lateral steering axis tilt gets greatly aimplified. I thinik it will work just wonderfully with a bogie forks with wheels spaced wide enough apart, and you can have suspension in a similar fashion like on Horn's bike too (but, again, flipped upside down). |
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Balor
Visitor (new) Joined: 25 January 2017 Status: Offline Points: 154 |
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OK, here is my take on it so far: Zero trail geometry and a steering damper for stability... maybe I should add a wee bit more trail after all, but I'll need to do actual experiments with a fairing... which is getting severely delayed due to Covid-related (and work-related) stuff :( It's is quite fine at speed up to about 50 kmh, but could not make it go faster yet w/o a fairing, but I think I want more stabilty after all (not to mention it is quite flimsy due to 3d printed connectors). Maybe I should go with the way of Matt Weaver and DIY myself an electronically controlled steering damper - should not actually be hard, just need to find a way to actuate the damping setting on existing damper with, say, a simple servo... Other than that, side wheels with steering damping should take care of strong unwanted toppling moments.
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RoyMacdonald
BHPC Member Joined: 09 March 2007 Location: Rye East Sussex Status: Offline Points: 960 |
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I'm impressed that you can get it to 50kph unfaired.
All the best. Roy
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AlanGoodman
Admin Group Club Chairman Joined: 04 March 2005 Location: United Kingdom Status: Offline Points: 7809 |
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Interesting choice of front tyre...
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Balor
Visitor (new) Joined: 25 January 2017 Status: Offline Points: 154 |
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Techically, nothing prevent me from hitting a steep hill, but here are not much of those around... so yea, that was on the flat, but accidentally with a different front wheel :) I've also experimented with installing low-power e-assist, it's a great help for starting and uphill boost. Ultimately, I want to install no less than two motors - a geared crank drive and dedicated regen brake, but I need to have it 'clutched' and this is not that easy. Offroad setup is, well, because I'm using it for offroad for now. Great fun actually :)
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