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 fwd-rws (lean steer)
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alevand
human power expert

USA
2929 Posts

Posted - 01/28/2017 :  05:18:07  Show Profile  Visit alevand's Homepage  Reply with Quote
Concept. I think rws is a misnomer here, maybe Kallie would be a better description. The seat is affixed to the pedals and steering, steering has positive trail. I haven't worked out the details, but it looks like virtual pivot steering won't work.

It would be a dual 700c low racer version of this:


https://www.youtube.com/watch?v=SVwmGiH-HPg




But not like this:



C:
Tony Levand

Edited by - alevand on 02/01/2017 03:45:17

Speedbiker
human power expert

USA
3755 Posts

Posted - 01/28/2017 :  06:24:17  Show Profile  Reply with Quote
Fun in a parking lot. Not fun at the speeds Tony goes down hills!
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Balor
recumbent guru

Russia
514 Posts

Posted - 01/28/2017 :  06:40:43  Show Profile  Reply with Quote
I think this is called 'centre-steer', not 'RWS' per se.
What are projected advantages, besides the fun of building and test-riding one?
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Runxner
recumbent enthusiast

USA
441 Posts

Posted - 01/28/2017 :  10:10:44  Show Profile  Reply with Quote
why would your weight to shift outward in turns?

Team Low-Life
Lowracer Test Pilot/Evangelist
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PUGZCAT
recumbent enthusiast

Canada
459 Posts

Posted - 01/28/2017 :  17:50:24  Show Profile  Reply with Quote
Hmm, the holy grail of recumbents, short direct chain line, positive trail, what could go wrong?
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Balor
recumbent guru

Russia
514 Posts

Posted - 01/29/2017 :  22:08:26  Show Profile  Reply with Quote
quote:
Originally posted by PUGZCAT

Hmm, the holy grail of recumbents, short direct chain line, positive trail, what could go wrong?



Well, if turn is initiated in front of CG it should work, in theory:
http://www.tonyfoale.com/Articles/Balance/BALANCE.htm
This is why center-steered bikes work. Otherwise it will work kinda like a bike with negative trail AFAIK - massively unstable no matter how rear steering is implemented in fact.
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alevand
human power expert

USA
2929 Posts

Posted - 01/30/2017 :  10:58:34  Show Profile  Visit alevand's Homepage  Reply with Quote
I keep saying it has POSITIVE trial, please let that sink in.

C:
Tony Levand
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PUGZCAT
recumbent enthusiast

Canada
459 Posts

Posted - 01/30/2017 :  16:33:03  Show Profile  Reply with Quote
Sort of like sitting on the cross bar of the handlebars on a BMX bike coasting down a hill, except with a slack headtube angle, a set of cranks and a linkage to steer it.
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Jerry
recumbent guru

USA
981 Posts

Posted - 01/30/2017 :  17:34:04  Show Profile  Reply with Quote
Get it done Tony, but only after you get the touring bike done. If anyone can make it work, I am betting on you.
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Balor
recumbent guru

Russia
514 Posts

Posted - 01/30/2017 :  21:37:05  Show Profile  Reply with Quote
quote:
Originally posted by alevand

I keep saying it has POSITIVE trial, please let that sink in.

C:
Tony Levand



As much as I understand, it does not really matter which wheel doing the turning, so long as the turn itself is initiated BEFORE CG and not by steering continuously in direction opposite to the turn itself.

This is what you mean by positive trail, I presume?

This particular bike neatly solves RWS problem (outward weight shift in turns, outlined by Ruxner) by exactly that.
Unfortunately, humongous negative offset and resulting trail + resulting steering inertia must make the bike not really fun to ride at high speeds indeed...
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alevand
human power expert

USA
2929 Posts

Posted - 01/31/2017 :  03:42:00  Show Profile  Visit alevand's Homepage  Reply with Quote
Contact patch behind steering axis.

C:
Tony Levand
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PUGZCAT
recumbent enthusiast

Canada
459 Posts

Posted - 01/31/2017 :  10:48:14  Show Profile  Reply with Quote
An interesting design, a slack head angle but the wheel flop can be equalized out by adjusting the rider's center of gravity behind the steering axis to get the desired amount of gravity self centering.
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alevand
human power expert

USA
2929 Posts

Posted - 02/01/2017 :  04:12:29  Show Profile  Visit alevand's Homepage  Reply with Quote
Added lean-steer to title.

C:
Tony Levand
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PUGZCAT
recumbent enthusiast

Canada
459 Posts

Posted - 02/03/2017 :  06:00:10  Show Profile  Reply with Quote
Is it lean steer?
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alevand
human power expert

USA
2929 Posts

Posted - 02/03/2017 :  06:40:14  Show Profile  Visit alevand's Homepage  Reply with Quote
What do you acronym a bike with the BB and seat movable, has positive trail and relatively normal steering inclination ~ 60 degrees? MBBS, MSBB RWS-PT, Kallie... hummm.

If this fwd motorcycle can be maneuvered, with all the steering inertia, then a bike with the weight on the rider on the front forks should be also, yes, but not as a rwd bike is.


C:
Tony Levand
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Runxner
recumbent enthusiast

USA
441 Posts

Posted - 02/03/2017 :  07:07:03  Show Profile  Reply with Quote
MRH moving rear hub. Are there really enough of them to need to split it down further?

Team Low-Life
Lowracer Test Pilot/Evangelist
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Balor
recumbent guru

Russia
514 Posts

Posted - 02/03/2017 :  08:37:55  Show Profile  Reply with Quote
quote:
Originally posted by alevand

What do you acronym a bike with the BB and seat movable, has positive trail and relatively normal steering inclination ~ 60 degrees? MBBS, MSBB RWS-PT, Kallie... hummm.

If this fwd motorcycle can be maneuvered, with all the steering inertia, then a bike with the weight on the rider on the front forks should be also, yes, but not as a rwd bike is.


C:
Tony Levand



OMFG! I think there is some technical trickery like power steering involved - if my MBB starts to flop under gravity, for instance, I simply CANNOT control it with the hand on the 'stem', my wrist simply gets twisted off!
This front triangle must weight like hundred kilograms, is it humanly possible to manuever it with any grace?

Well, come to think about it, the weight seems rather closely packed around steering axis, steering inertia increase#1099; linearly with weight but r^2. Still, I simply see no advantages besides unconventionality for unconventionality sake.
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Speedbiker
human power expert

USA
3755 Posts

Posted - 02/03/2017 :  09:34:42  Show Profile  Reply with Quote
Despite its stablity and apparent ease to ride, why would anyone build something with such dangerous ride characteristics?
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PUGZCAT
recumbent enthusiast

Canada
459 Posts

Posted - 02/03/2017 :  16:38:54  Show Profile  Reply with Quote
I would hazard to guess that there is plenty of self centering with the weight of the power train behind the steering axis. I didn't know that Gene Wilder was into experimental motorcycles.
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alevand
human power expert

USA
2929 Posts

Posted - 02/03/2017 :  17:09:40  Show Profile  Visit alevand's Homepage  Reply with Quote
I see what you mean, no Helmet, shorts, tennis shoes and a t-shirt.

quote]Originally posted by Speedbiker

Despite its stablity and apparent ease to ride, why would anyone build something with such dangerous ride characteristics?
[/quote]

C:
Tony Levand
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Balor
recumbent guru

Russia
514 Posts

Posted - 02/03/2017 :  23:10:49  Show Profile  Reply with Quote
quote:
Originally posted by PUGZCAT

I would hazard to guess that there is plenty of self centering with the weight of the power train behind the steering axis. I didn't know that Gene Wilder was into experimental motorcycles.



Yea, basically it is it's own counterweight. If one account for the weight of legs and distance to steering axis, would MBB be THAT much different I wonder?
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Runxner
recumbent enthusiast

USA
441 Posts

Posted - 02/04/2017 :  01:52:27  Show Profile  Reply with Quote
no different than riding a DF with someone sitting on the handlebars.

Parade bike? To test the theory for a different application. He'd be scraping hard parts with moderate lean at high speed.

Team Low-Life
Lowracer Test Pilot/Evangelist
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