[python] Re: Positive Trail using Hubless Wheel - use 4-bar link steering instead?

  • From: bren102 <bren102@xxxxxxxxx>
  • To: python@xxxxxxxxxxxxx
  • Date: Thu, 28 Jul 2011 08:51:20 -0700 (PDT)

Hi Dirk,

I did come across Jürgens mention just this morning :-) ie Monday, April 18, 
2011 3:38 AM "virtual steering pivot idea again".

I have also recently read how not only does gyroscopic effects, but also trail 
effects appear to have no bearing upon self-righting ability. If that is so, 
then researching the effects of trail using 4-bar linkages may likely go 
nowhere.

The list archive at http://www.freelists.org/archive/python/ is searchable, 
however, attachments do not appear to be saved with text eg 
http://www.freelists.org/post/python/4-bar-linkage contains a link for: 
http://www.freelists.org/archives/python/09-2004/gif3UvrApaVNd.gif
Is there a way to retrieve the attachments?

Regards,

Brendan



--- On Thu, 7/28/11, dirk@xxxxxxxxxx <dirk@xxxxxxxxxx> wrote:

From: dirk@xxxxxxxxxx <dirk@xxxxxxxxxx>
Subject: [python] Re: Positive Trail using Hubless Wheel - use 4-bar link 
steering instead?
To: python@xxxxxxxxxxxxx
Received: Thursday, July 28, 2011, 1:45 AM


 
    
 
 
  
   
    
    Hi,
   
  
   
  
   if you dig through this list, you'll find some four bar linkage footage as 
well. Jürgen posted links to pictures some time ago. 
  
  
  greetings,
  DirkS 
   
  
   

   bren102 <bren102@xxxxxxxxx> hat am 28. Juli 2011 um 03:56 geschrieben:
   

   

   > Further thoughts:
   

   >
   

   > As well as raising the seat to maintain the line from the steering head 
axis to hips to reduce PSI, another problem is the extra weight from all the 
bearings and guides used to make the hubless wheel.
   

   >
   

   > Seems an easier way to go to maintain seat rising effect while creating 
positive trail is to use a 4-bar link for steering, creating a virtual positive 
trail. I created many drawings some years ago to figure out a working model. 
Will dig around to see if I can find them.
   

   >
   

   > Regards,
   

   >
   

   > Brendan
   

   >
   

   > --- On Tue, 7/26/11, bren102 <bren102@xxxxxxxxx> wrote:
   

   >
   

   > > From: bren102 <bren102@xxxxxxxxx>
   

   > > Subject: [python] Re: Fw: Positive Trail using Hubless Wheel?
   

   > > To: python@xxxxxxxxxxxxx
   

   > > Received: Tuesday, July 26, 2011, 5:57 PM
   

   > > Hmm, it seems to me not necessarily a
   

   > > flevo or speculoos type steering as they have no seat rising
   

   > > effect to aid stability.
   

   > >
   

   > > As a technical exercise - looking at Dirk's python, extend
   

   > > the steering head forward horizontally to within the front
   

   > > wheel, but not past the front wheel axle, maintaining the
   

   > > same steering angle until the trail is positive.
   

   > >
   

   > > The seat rising effect still applies as the steering head
   

   > > is still at the same angle and is not horizontally higher
   

   > > than the front wheel axle.
   

   > >
   

   > > So, a python with positive trail!
   

   > >
   

   > > Maybe I should create a diagram?
   

   > >
   

   > > Regards,
   

   > >
   

   > > Brendan
   

   > >
   

   > >
   

   > > --- On Mon, 7/25/11, Michael Ostermeier <list@xxxxxxxxxxxxxxxxxx>
   

   > > wrote:
   

   > >
   

   > > > From: Michael Ostermeier <list@xxxxxxxxxxxxxxxxxx>
   

   > > > Subject: [python] Re: Fw: Positive Trail using Hubless
   

   > > Wheel?
   

   > > > To: python@xxxxxxxxxxxxx
   

   > > > Received: Monday, July 25, 2011, 3:48 PM
   

   > > > Hi,
   

   > > >
   

   > > > bren102 wrote:
   

   > > > > Perhaps the rider can be seated higher to
   

   > > maintain hip
   

   > > > alignment with the steering axis?
   

   > > >
   

   > > > Yes, but then you wont have a lowrider and end up
   

   > > having a
   

   > > > Flevobike.
   

   > > >
   

   > > > >> >> […] may allow a python with
   

   > > positive
   

   > > > trail to be built.
   

   > > >
   

   > > > This will get you a speculoos-type bicycle.
   

   > > >
   

   > > > Regards
   

   > > >
   

   > > > Miche
   

   > > >
   

   > > > PS: see: http://en.openbike.org/wiki/Front_Wheel_Driven_Bicycle
   

   > > >
   

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