Rhisiart Gwilym wrote:
Hi Erik!Have you run across Dennis Renner's interesting FWDRWS bike yet? He reckons that it's a RWS, though looking at the vid, I'd say centre-steer is a more accurate description. You can see how easily it handles here: http://recumbentsartandpoems.blogspot.com/ (last video, right at the bottom of the page)
Last week, someone attended me to it.According to my definition, it is really a rear wheel steered vehicle, because the complete seat part is attached to the front wheel part. As we talk about a centre steered vehicle, I'd rather think of a Flevobike, which is actually front wheel steered in my definition, but the place of the steering mechanism is at the centre. I was really surprised to see how Dennis could ride this bicycle. I didn't expect it would be possible to ride such a vehicle in a so recumbent position.
And Dennis discusses it briefly with other recumbent riders here:http://www.cyclingcrowd.com/Uwe/Forum.aspx/recumbent/5099/Strange-Recumbentwhere he confirms that it handles easily at both slow and high speeds, has a good turning circle, and never feels dangerous. This is his rebuild, after a Mark 1 model that had all the usual bad characteristics of many pioneers' previous failed attempts at a FWDRWS.Even if it is a centre-steer really, it does have that vital characteristic of a real FWDRWS: that the rider sits on the front half of the bike, like the Kalle. Unlike the Kalle, though, the steering axis strikes the ground well behind the front wheel. Really that's like the negative trail of the Pythons (under Jurgen's encouragement, and the network of Python builders, I have one of my own nearing completion now). If it is really a Python, then it has the longest negative trail of any so far. Yet so stable and easy riding!In the 'Frame Geometry' section of Jurgen's Python website, there's an animation of the self-centring effect caused by the head-tube angle; see here:
Interesting. Unfortunately I don't have enough time now to study it thoroughly and to write about it on my RWS web site, but I will certainly do that later. I will save your mail for that purpose.
One of my reasons for thinking of Dennis's bike as really a self-centring centre-steer rather than a true FWDRWS is that the side view on a freeze-frame on the vid makes it very clear that the axis of articulation passes right up through the rider's back, very like other centre-steers, whereas a true FWDRWS would have this axis well behind the rider.
Maybe there lies the secret of this success?
Notice that Dennis's riding position is properly recumbent, though. He doesn't have to ride in a fairly upright posture to get the control and stability that his bike shows.In a recent email to me, Dennis says this:"The wheel base is 45 inches, and the steering head tube angle is 71 degrees. The steering system on my bike is a split handle bar design. Each side moves only backwards and forwards like joy sticks. A control rod system is designed so that the brain still thinks it is turning the front wheel like a normal bike."Incidentally, in the old language which has been in continuous use here in Britain longer than any other still extant tongue (Cymraeg), you can pronounce FWDRWS as a speakable word. It sounds like 'vood-roos'. Doesn't really mean anything in Cymraeg, but it has a nice sound to it. Could that be a good name for this kind of bike.....? I find that I've taken to calling it by that name to myself, and already it has a familiar, easy ring to it.
I have been in Cymru twice. And I will be there more often, because I liked the country. Of course I cannot understand a word in Cymraeg, but at least I know some pronounciation rules.
Thanks for your mail and good byke, Erik Wannee. ============================================================ This is the Python Mailinglist http://www.freelists.org/list/python Listmaster: Jürgen Mages jmages@xxxxxxTo unsubscribe send an empty mail to python-request@xxxxxxxxxxxxx
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