[python] Email to Erik Wannee, about his RWS-page

  • From: Rhisiart Gwilym <Rhisiart@xxxxxxxxxxxxxx>
  • To: Erik@xxxxxxxxx
  • Date: Sun, 15 Feb 2009 10:47:57 +0000

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)

And Dennis discusses it briefly with other recumbent riders here:

http://www.cyclingcrowd.com/Uwe/Forum.aspx/recumbent/5099/Strange-Recumbent

where 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:

http://www.python-lowracer.de/geometry.html

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.

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.

Yours,  Rhisiart Gwilym

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