gmane.culture.transportation.humanpowered.general

RWS (trail)

Reg Rodaro — 2012-04-26T13:27:13

In 2002 I rode a RWS Stormy Weather velomobile at the HPVA World
Championship in Canada.
  I rode in several events and for the most part the RWS part of the vehicle 
was ignored.
As it was fully faired I rode with the streamliners I have the memory of 
being lapped several
times by the Varna, Barracuda, and Keno;s liner.
   I constructed the steering so the trail could be adjusted. I started with 
2 inches of positive trail
and over time adjusted to less and less to settle down the stability and 
feel.
 The closer to 0 trail the feel improved. Between 1/2 inch and 3/4 inc of 
negative trail
was the optimal setting for the experiment.
   RWS works fine if properly executed and allowed for a simple low friction 
FWD.

                        Reg Rodaro

 

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Re: Buckminster Fuller's Dymaxion Car

Dave Larrington — 2012-04-26T07:29:41

RWS works fine if its done properly.  Back in the early 80s a chap named 
Simon Sanderson built a thing named "Panzer" (the least-appropriately named 
thing ever to hit the roads of BRITAIN until the introduction of the 
Mitsubishi Carisma), which was FWD, RWS and perfectly roadable.  Simon was 
working in London and weekend commuting back to Norfolk at the time, IIRC, 
and could do the trip at better than 20 mph average speed.

Re: Buckminster Fuller's Dymaxion Car

Moz — 2012-04-26T01:22:43

I hear that vehicle was quite interesting to drive. And "held it's line"
meant "kept within a 100 metre wide strip". Admittedly, at 300m/s that's
fairly impressive. I read a book on the effort and there was some odd
combination of half second witlag in the steering and not a lot of
steering movement that meant it took a while for the pilot to get the hand
of controlling it at all.


Mind you, Christiana sell a lot of pivot-steer trikes that have most
of the same issues of dynamic instability and few people complain.

Moz

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Re: Thrust SSC steering

Cornel.Ormsby — 2012-04-26T00:11:15

My apologies for the incorrect URL, it is:
 
http://www.thrustssc.com/thrustssc/Engineering/rearster.html
 
++ Cornel Ormsby ++
+Las Vegas, Nevada+

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Re: Buckminster Fuller's Dymaxion Car

Cornel.Ormsby — 2012-04-26T00:02:12

 
 
It's a common misconception. In 1997 the rear-wheel steering Thrust SSC (driven by RAF Wing Commander Andy Green) held its line flawlessly as it went faster than sound at Black Rock, about 380 miles north-northwest of where I am sitting now. 
 
http://www.thrustssc.com/thrustssc/contents_frames.html
 
++ Cornel Ormsby ++
+Las Vegas, Nevada+

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Re: Dymaxion

Charlie Buchalter — 2012-04-25T23:29:07

All of the issues with rear wheel steering mentioned so far are part of the
problem, but not the major problem. The major problem with rear wheel
steering is that it is dynamically unstable. As pointed out, modern computer
controls can overcome this, but it doesn't change the basic instability of
the mechanical system. 

Charlie Buchalter
Atoc Inc.
www.Atoc.com
www.TopperRacks.com
www.Draftmaster.com





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Re: Dymaxion

John Riley — 2012-04-25T22:56:06

On Apr 25, 2012, at 3:25 PM, Paul Gracey wrote:

Engine behind the axle is still used by Porsche. Many race and performance cars have the engine ahead of the rear wheels, as the Dymaxion did. The unusual thing about the drive train was that the rear engine drove the front wheels. 
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Re: Dymaxion

Moz — 2012-04-25T22:49:43

I'm not convinced. The big issue for rear steering only on roads
is curbs. To move away from a curb the rear steer has to move the
rear end towards the curb. Which kind of works with the Dymaxion
because it's wider at the front than the rear. But for a rectangular
vehicle that's not possible. So you have to reverse away from the
curb. Which is bearable for parking, but easily fatal when you
drift too close to a motorway barrier.

Remember, on the road it's all about failure modes. Just working
is not enough, it has to fail gracefully.


This is the bit that computer control can fix. Some fighter planes
IIRC are so grossly unstable that humans can't operate them without
computer control. Which is great for maneuverability, but not so hot
if the computer fails.

Moz

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Re: Dymaxion

Paul Gracey — 2012-04-25T22:25:19

On Apr 25, 2012, at 9:00 AM, hpv-request< at >hupi.org wrote:

Eric Edwards streamliner Pegasus is rear steering and I managed to get it around the San Diego Velodrome once a long time ago even though it was designed only for straight line speed.  What made it work ( just barely) was the friction he included to control its tendency to oscillate with a positive feedback. It also was set up to have the steering axis line reach the ground forward of the contact patch as most steering needs. It did have trail, but only within a narrow range of its motion, so that I had it at full lock most of the way around the oval and entered the corners as wide as possible. Bucky's machine couldn't have had such strictures and do what he promised it could do. Today we would just build it with all-wheel steering and stability controls like modern cars.  

The rear engine idea did not die with the Dymaxion as anyone who owned a VW or a Corvair can attest. I owned both at one time. I took my VW up to Big Bear lake in winter once and

Re: Rear Steering

Andy jacoby — 2012-04-25T17:19:03

We had a phenomenal wipe-out at the Fl HPV race a few years back. Somebody not involved with the usual HPV bunch had designed a streamliner with front wheel drive and two back steer wheels. While flying high on the turn at the velodrome the steering gave way and the thing spun round and almost over the top. The driver/rider was not hurt but his ride was out of commission.

Andy


________________________________
 

     

On 4/24/2012 1:52 PM, Ben Brown wrote:

Yes, they crashed but had good PR.

My recollection is that after one car overturned, they only allowed professional race car drivers to drive them (I think on the basis that they had good reflexes and were used to driving all sorts of wild things).


Brian
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Re: Buckminster Fuller's Dymaxion Car

Sara & Warren Eldberg — 2012-04-25T16:15:50

As a FWD/FWS it would have been great.  But just like every efficient,
aerodynamic design, from the 1920's until today, it would have lost out to
big, uninspired boxes, run on cheap fuel.  Unfortunately, the price at the
pump will never reflect the true costs of gas....until the ice caps are a
memory.

Warren
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Re: Buckminster Fuller's Dymaxion Car

Brian H Wilson — 2012-04-24T23:00:42

Yes, they crashed but had good PR.

My recollection is that after one car overturned, they only allowed 
professional race car drivers to drive them (I think on the basis that 
they had good reflexes and were used to driving all sorts of wild things).

Some of what Bucky did was amazing, some of it was smoke and mirrors.

He would have been a great HPV'er, he was perfectly willing to try 
things that we all just know don't work, like rear wheel steering. Too 
bad it does not really work...

Seems to me the FlevoBike was kind of like that. Someone will probably 
pipe up now and say the FlevoBike was the best thing ever invented.

One thing I learned hanging out in the HPV world is that human beings 
can ride damn near anything with 1 or more wheels on it, and often even 
have fun with it.

This is a good read: http://dymaxioncar.com/restoration.html

Brian

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Buckminster Fuller's Dymaxion Car

Ben Brown — 2012-04-24T20:52:31

I just watched this video of Buckminster Fuller's Dymaxion Car:
http://www.youtube.com/watch?v=YlLZE23EJKs
I was surprised that the vehicle seems to handle just fine with 
rear-wheel steering--something generally considered unworkable. Does 
anyone know the secret of how this works? An overview of the vehicle is at
http://www.nytimes.com/2008/06/15/automobiles/collectibles/15BUCKY.html

Thanks, Ben

_____________________________________________

H. Ben Brown
Project Scientist
Robotics Institute
Carnegie Mellon University
5000 Forbes Avenue
Pittsburgh, PA 15213-3891
hbb< at >cs.cmu.edu
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Re: Open Source hpv plans posted

Christine and Stephen Nurse — 2012-02-27T10:29:15

Hi Ph.T (is that your real name?) and everyone.

These bikes work just like any fwd fixed bottom bracket design, that is, the chain comes from somewhere near the steering axis before it goes to the front wheel.  So when the steering twists, the chain twists too, but doesn't actually displace much.  Standard rear derailleurs mash up the chain in a horrible way during gearshifts, so this drive compromise doesn't worry the bike much. You can either have the chain quite close to the steering axis like some front wheel drive bikes with pulleys, or this bevo bike http://www.velovision.com/forum-new/read.php?5,8669 or limit the steering during pedalling in some way.  I have trouser guards or outside catcher rings on the chainring and limit the steering during pedalling by having my knees inside the steering bars and it all works.

I hadn't seen those trikes before I did a google search for open source recumbent. But I quite like them.

Regards

Steve Nurse




----- Original Message ----- 
  From: Ph.T 
  To: Chris

Re: Open Source hpv plans posted

Ph.T — 2012-02-26T22:42:07

I've never seen these trikes before: very inspiring for home builders .
http://www.n55.dk/manuals/spaceframevehicles/spaceframevehicles.html
. I'm not sure I understand your bike's design;
when you steer, does it twist the chain ?
and does that tend to derail you sometimes ?


On Sun, Feb 26, 2012 at 4:14 AM, Christine and Stephen Nurse <
christine< at >typing2000.com.au> wrote:

Open Source hpv plans posted

Christine and Stephen Nurse — 2012-02-26T11:14:55

Hi, Thanks to Ihab and others who commented on my post previously, I've put 
a free set of plans for my bike on line and hope the posting will lead to an 
open source developement.

See 
http://modularbikes.blogspot.com.au/2012/02/starting-monsterbike-open-source-hpv.html 
for a link to the plans and

and 
http://modularbikes.blogspot.com.au/2012/02/survey-of-open-source-recumbent-bike.html 
for my survey of open source hpvs.

At the moment I'm not on facebook so couldn't explore the links to any 
facebook sites.

Regards

Steve Nurse


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Re: Fw: Open Source Hpv bike

2012-02-21T19:15:09

On Tue, Feb 21, 2012 at 2:27 AM, Christine and Stephen Nurse <
christine< at >typing2000.com.au> wrote:


:)



That's pretty nifty. I like the idea of a whole family of big/small wheel
FWD bents where moving-BB vs. twist-chain is a design parameter dependent
on the rider's preference.

I for my part have not had enough experience with moving-BB to tell whether
I like it. I have ridden various of them at Nanda Holz's dealership:

  http://www.spincyclz.com/

I found the Cruzbike Quest to be very easy to get used to:

  http://www.cruzbike.com/quest

but the Cruzbike Vendetta was scary and I'd need a much longer time, if
ever, to get accustomed to it:

  http://www.cruzbike.com/vendetta

Oh, and I almost forgot, videos from a very poor cinematographer

These are great, actually. With bikes, a video is worth a thousand pictures
;) because pictures don't generally show the sense of motion.

I love how you blew by the wedgie in the 1st one! :) The "inner trailer" is
pure genius!

The only problem with the videos is y

Fw: Open Source Hpv bike

Christine and Stephen Nurse — 2012-02-21T10:27:53

----- Original Message ----- 
From: Christine and Stephen Nurse 
To: ihab.awad< at >gmail.com 
Sent: Tuesday, February 21, 2012 8:21 PM
Subject: Re: [hpv] Open Source Hpv bike

Thanks Ihab, lucky I didn't read the brol thread when I was thinking of these things, there are a few nay sayers out there!

Another large front wheel design I've done (and plans are there) is at http://www.modularbikes.com.au/zeica/

For me the small wheel at the back allows for a very simple, large carrying capacity, highly visible tail box which has great advantages for a practical vehicle used for shopping and general transport.  My latest bike can even carry a carton of beer, and I've done several 150k plus day rides on it. But not carrying beer!

Oh, and I almost forgot, videos from a very poor cinematographer

http://www.youtube.com/watch?v=45U6KCbwHhA

http://www.youtube.com/watch?v=nwszbeCdG4g
 and

http://www.youtube.com/watch?v=CYPaGwRzC9c

Regards

Steve

Regards

Steve Nurse

  I had a [sort of] similar thought recently; ch

Re: Open Source Hpv bike

2012-02-21T01:48:34

Hey Steve,

On Mon, Feb 20, 2012 at 3:18 AM, Christine and Stephen Nurse <
christine< at >typing2000.com.au> wrote:



I had a [sort of] similar thought recently; check out this BROL thread:

http://www.bentrideronline.com/messageboard/showthread.php?p=853405#post853405

Your bikes are great! Keep up the good work!

Cheers,

Ihab

Re: Open Source Hpv bike

Ph.T — 2012-02-21T01:26:19

thank you for contributing to opensource,
I found something like that on facebook,
only it's for open source cloroplast velomobile shell designs;
http://www.facebook.com/groups/15644592486/
maybe with your knowledge of keywords in your domain,
you can find something there too .


On Mon, Feb 20, 2012 at 4:18 AM, Christine and Stephen Nurse <
christine< at >typing2000.com.au> wrote:

Open Source Hpv bike

Christine and Stephen Nurse — 2012-02-20T11:18:52

Hi

To further my bike designs, I'm interested in publishing some of them as open source type plans.  Does anyone have good reccommendations for a site that would host such a venture?

I'm interested in posting designs, getting feedback, listing suppliers etc. and the bikes I'm working on are at http://modularbikes.com.au/bigatthefront.html

The bikes can be fairly simple, fast and effective and carry reasonable loads.  Already I've come across a few websites like http://www.python-lowracer.de/ and http://en.openbike.org/wiki/Main_Page and http://www.openwaterbike.com/ 

Thanks, Regards

Steve Nurse
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