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THE LOGIC OF TRIKES an outsider's viewpoint by Andre Jute



 
 
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  #11  
Old June 4th 09, 03:17 AM posted to alt.rec.bicycles.recumbent
Tom Sherman °_°
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Posts: 344
Default THE LOGIC OF TRIKES an outsider's viewpoint by Andre Jute

gotbent aka FRT rider wrote:
"Andre Jute" wrote in message
...
THE LOGIC OF TRIKES
an outsider's viewpoint
by Andre Jute

snippage of large volumes of trite verbiage

Andre. Andre, Andre, I'm speaking as someone who has an insider's viewpoint
and I must say that you've typed a term paper full of nonsense. You have an
intense prejudice against recumbent bicycles and have gone to great length
to show that, and have not made a single substantial argument that could
stand up the careful scrutiny of a peer review.

Just because you actually own and ride a recumbent trike makes you think
you know more than The André Jute aka Andrew McCoy?

Watch out, or Mr. Jute will add you to his imaginary kill-file!

--
Tom Sherman - 42.435731,-83.985007
I am a vehicular cyclist.
Ads
  #12  
Old June 4th 09, 12:53 PM posted to rec.bicycles.tech,alt.rec.bicycles.recumbent
Bernhard Agthe
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Posts: 210
Default THE LOGIC OF TRIKES an outsider's viewpoint by Andre Jute

Hi,

Andre Jute wrote:
On Jun 3, 6:13 pm, Opus wrote:
I don't see recumbent chains as having any more problems than chains

....
You don't consider those disadvantages? It's your list, pal, not mine,


Why? As you said, chains last:

but I must tell you that my bikes have chains serviced twice a year
that last almost forever. Anything less is an imposition on my time
and patience by an incompetent designer.


If I wanted to make fun of Andre Jute, I would ask him if he rides so
little ;-) But then, I do chain service only twice yearly, as long as I
don't count the few drops of oil I drip on my chain every now and then.
Which I don't.

The tipover point for a multi-

....
Yes, that's what I said, but you cut it away. Here it is again:


Probably one can use different words to describe the same thing, which
is understood differently by someone else?

"The flipover line on a tricyle runs between the centres of the
contact
patches of the front inside tyre in the corner and the single rear


OK, you draw lines between the contact patches of all three wheels. The
gravity vector from COG towards the ground must stay inside that
triangle to prevent any unstable situation.

Actually it's the same on a "normal" bike, you have an area defined by
the contact patches of rear and front wheel, which the "gravity vector"
must stay inside. Otherwise you "flip". With a trike, that area is
simply shaped differently and is larger sideways. Have you ever tried
what happens, when you go around a sharp corner at speed on an upright
bike without leaning correctly? So, no difference to a trike... You can
even "lean" on a trike - by bending your body sideways ;-)

tyre. Thus, to make the thing corner well, it is necessary to move
the
CoG as near to over the front axle as is possible in order to get it
as far as possible from the flipover barrier. This is impossible to
do
if the rider's feet are to be inside the wheelbase or at least not
too...


Why would you want the rider's feet inside the wheelbase? What's the
reason? On an upright bike, the the feet are outside the wheelbase
(sideways), so why should they be inside on a trike?

All tadpole designs I know of, do exactly what you posulate - the front
"axle" is very close to the rider (who basically defines COG, unless the
trike is extremely heavy).

Suspension linkages can only make this happen sooner rather than later
by causing the sideways motion of the vehicle load away from the...


This would actually be an interesting design - build a tadpole trike
with the front wheels on sprung beams (Andre, you just asked about leaf
springs on a bike frame - here you go...). Of course there's some room
to set this up so that the relation of COG to wheel contact patch does
not get influenced in a negative manner...

This is wrong, probably arising from your expectation that any
suspension applied will result in a roll centre above ground. In the

....

So go ahead, design an example front wheel suspension - though I'm not
sure, any "linkage" is necessary. I expect it should be possible to
build a trike with the front wheel outriggers acting like leaf springs.
I'm not sure about the performance that would have, but from a design
and maintenance point-of-view that would be good...

Another thing you mention is "leaning" trikes. Though I understand the
basic principle, I do have a question: the correct amount of "lean"
depends on the actual speed. All of the designs I know of work with
purely mechanical linkage (steering angle proportinal to lean angle).
But that would be wrong, because it only works for a certain speed. So,
unless I'm wrong, "leaning" trikes are no better than trikes with a
fixed front "axle"? Why bother with the weight and mechanics, then?

Here is my full post again; it is internally and externally coherent

....

Please, don't re-post this. Any reader can go back and read the original
- if you care, put it on your website and provide a link. Saves download
time ;-)

Have fun...

PS: Actually I think Trikes are a question of personal style and as such
you either like them or not. But I cannot project my opinion on someone
else, just like you like racing bikes better than mountain bikes or
whatever you want.

PPS: There's a number of cyclecar designs available, most based on
tadpole trikes. If you ask me, you could junk press all SUV cars - but
some people seem to like them...
  #13  
Old June 4th 09, 05:43 PM posted to rec.bicycles.tech,alt.rec.bicycles.recumbent
Jeff Grippe
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Posts: 277
Default THE LOGIC OF TRIKES an outsider's viewpoint by Andre Jute


"Andre Jute" wrote in message
...
THE LOGIC OF TRIKES
an outsider's viewpoint
by Andre Jute

big snip

You've got to be kidding! If you ever wanted to convince me not to read any
of your books, you have succeeded. Sheesh!


  #14  
Old June 4th 09, 06:49 PM posted to rec.bicycles.tech,alt.rec.bicycles.recumbent
Edward Dolan
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Posts: 14,212
Default THE LOGIC OF TRIKES an outsider's viewpoint by Andre Jute


"Bernhard Agthe" wrote in message
...
Hi,

Andre Jute wrote:

[...]

Here is my full post again; it is internally and externally coherent

...

Please, don't re-post this. Any reader can go back and read the original -
if you care, put it on your website and provide a link. Saves download
time ;-)


Andre Jute is a crackpot. Can't you tell the type when you see it? He only
reads his own words and the more he sees them on various posts, the better
he likes it.

Andre Jute has all the coherency of the certifiably insane and he should be
in a lunatic asylum. His dumb ass is not even worth kicking.
[...]

Regards,

Ed Dolan the Great - Minnesota
aka
Saint Edward the Great - Order of the Perpetual Sorrows - Minnesota


  #15  
Old June 4th 09, 07:07 PM posted to rec.bicycles.tech,alt.rec.bicycles.recumbent
Edward Dolan
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Posts: 14,212
Default THE LOGIC OF TRIKES an outsider's viewpoint by Andre Jute


"Jeff Grippe" wrote in message
m...

"Andre Jute" wrote in message
...
THE LOGIC OF TRIKES
an outsider's viewpoint
by Andre Jute

big snip

You've got to be kidding! If you ever wanted to convince me not to read
any of your books, you have succeeded. Sheesh!


When I first got into bicycling many years ago I read several books about
bicycles that were also gibberish. Let's face it, the mechanical engineering
types barely know how to write anything that you can make sense of.

Tom Sherman writes extremely well for an engineer. He occasionally uses too
much engineering jargon, but I suspect he is just testing our patience. I
think he must have taken some liberal arts courses when at college. But
Andre Jute is far more typical of the type. Reading what he writes turns
your brain to mush.

Regards,

Ed Dolan the Great - Minnesota
aka
Saint Edward the Great - Order of the Perpetual Sorrows - Minnesota




  #16  
Old June 4th 09, 07:21 PM posted to rec.bicycles.tech,alt.rec.bicycles.recumbent
someone
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Posts: 2,340
Default THE LOGIC OF TRIKES an outsider's viewpoint by Andre Jute

On 4 June, 19:07, "Edward Dolan" wrote:
"Jeff Grippe" wrote in message

m...



"Andre Jute" wrote in message
...
THE LOGIC OF TRIKES
an outsider's viewpoint
by Andre Jute


big snip


You've got to be kidding! If you ever wanted to convince me not to read
any of your books, you have succeeded. Sheesh!


When I first got into bicycling many years ago I read several books about
bicycles that were also gibberish. Let's face it, the mechanical engineering
types barely know how to write anything that you can make sense of.

Tom Sherman writes extremely well for an engineer. He occasionally uses too
much engineering jargon, but I suspect he is just testing our patience. I
think he must have taken some liberal arts courses when at college. But
Andre Jute is far more typical of the type. Reading what he writes turns
your brain to mush.

Regards,

Ed Dolan the Great - Minnesota
aka
Saint Edward the Great - Order of the Perpetual Sorrows - Minnesota


For what Andre was attempting to explain, a picture book would be so
much better. Whether or not he was correct in his explanation of
ideas I'm not too sure. I could follow some of it precisely because I
have considered the problem myself. I also drew a similar conclusion
in that trikes serve a limited market and have little suitability to
go fast without an alternative energy source.

I was not fully awake when reading the 'gibberish', so considered that
to be fundamental in my inability to comprehend the text to my
satisfaction. I consider it tooo long to re-apraise, now I'm awake,
in what the author effectively draws the same conclusion as myself.
  #17  
Old June 4th 09, 07:35 PM posted to rec.bicycles.tech,alt.rec.bicycles.recumbent
Andre Jute[_2_]
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Posts: 10,422
Default THE LOGIC OF TRIKES an outsider's viewpoint by Andre Jute

On Jun 4, 12:53*pm, Bernhard Agthe wrote:
Hi,



Andre Jute wrote:
On Jun 3, 6:13 pm, Opus wrote:
I don't see recumbent chains as having any more problems than chains

...
You don't consider those disadvantages? It's your list, pal, not mine,


Why? As you said, chains last:


I did say so, but there were conditions. The chains on my bikes are
single chains in fully enclosing chaincases, driving enclosed hub
gear, no derailleurs, no idlers, no slack, no sideways movement. Show
me a tadpole trike with a similarly cosseted chain, or even one on
which it may be possible to fit such a thing, and we can reopen the
discussion.

If I wanted to make fun of Andre Jute, I would ask him if he rides so
little ;-)


Now why should anyone who isn't a psychopath want to make fun of a
harmless little old bespectacled intellectual? Doesn't make sense, you
know. Anyway, my riding ideal is only 50 klicks a week. Last week the
weather was so good, I made over a 100. But any day on which I get out
on my bike is good day. Bring back global warming!

No, seriously, the two most serious cyclists I've met in my time on
RBT are Jobst and Jay Bollyn. Jobst rides a gazillion uphill miles on
a bike from the Middle Ages of Cycling, and Jay does 5000 hard miles
through Chicago's everlasting, nasty winter every year, on a bike much
like my Dutch city bikes. I don't even have the time to aspire to
being such a hard rider, though I'm now so nearly fit I might in a
year or two work up to the puff.

But then, I do chain service only twice yearly, as long as I
don't count the few drops of oil I drip on my chain every now and then.
Which I don't.


But I do. If I have to go to the trouble of getting out an oil can,
that's a service, and it is time I could have spent with my family or
friends or working or riding the lanes. Service-free means exactly
what it says, no service.

The tipover point for a multi-

...
Yes, that's what I said, but you cut it away. Here it is again:


Probably one can use different words to describe the same thing, which
is understood differently by someone else?


Yes, I should have. Sorry, Opus.

"The flipover line on a tricyle runs between the centres of the
contact
patches of the front inside tyre in the corner and the single rear


OK, you draw lines between the contact patches of all three wheels. The
gravity vector from COG towards the ground must stay inside that
triangle to prevent any unstable situation.


The "unstable situation" will end shortly when rider and bike land
upside down in the ditch. But yeah, that's exactly it.

Actually it's the same on a "normal" bike, you have an area defined by
the contact patches of rear and front wheel, which the "gravity vector"
must stay inside. Otherwise you "flip". With a trike, that area is
simply shaped differently and is larger sideways.


True in strict theory. But in practice the front tyre contact patch on
a two-wheeler is not so narrow. Because the weight of the bike and
payload is essentially vectored directly through the contact patch,
and a two-wheeler is free to lean over, and can do so safely unless
the payload does something silly, the dynamic effective or "virtual"
contact patch width is many multiples of the static contact patch.

It's a huge advantage.

Have you ever tried
what happens, when you go around a sharp corner at speed on an upright
bike without leaning correctly?


I see the lean of the bike as an advantage which makes the area
outside which the gravity vector, as you have it, must not be
produced, so much wider.

So, no difference to a trike... You can
even "lean" on a trike - by bending your body sideways ;-)


Won't get you too long a stay of execution unless the trike's wheels
can lean over like a bike's. But if the non-tilting trike's rider were
to sit on a boom that pivots on the bottom bracket (possible with
shaft drive and universal joints to keep pedalling at any likely
angle, yes?) he could gain a decent advantage, as sailracers on sand
do.

tyre. Thus, to make the thing corner well, it is necessary to move
the
CoG as near to over the front axle as is possible in order to get it
as far as possible from the flipover barrier. This is impossible to
do
if the rider's feet are to be inside the wheelbase or at least not
too...


Why would you want the rider's feet inside the wheelbase? What's the
reason?


Safety of rider and pedestrians and automobile bodywork. Psychology of
rider and pedestrians. Simply not looking naff.

On an upright bike, the the feet are outside the wheelbase
(sideways), so why should they be inside on a trike?


Technically a valid point. It is a matter of acceptance, besides the
other considerations mentioned above.

All tadpole designs I know of, do exactly what you posulate - the front
"axle" is very close to the rider (who basically defines COG, unless the
trike is extremely heavy).

Suspension linkages can only make this happen sooner rather than later
by causing the sideways motion of the vehicle load away from the...


Hang on a minute. I didn't write that, and what is more, I don't agree
with it because it is correct only under very limiting conditions, and
I said so.

This would actually be an interesting design - build a tadpole trike
with the front wheels on sprung beams (Andre, you just asked about leaf
springs on a bike frame - here you go...). Of course there's some room
to set this up so that the relation of COG to wheel contact patch does
not get influenced in a negative manner...


The links I described for creating a leaning trike are equal length
parallel wishbones. If you substitute a leaf spring the length of the
link will vary in motion. I think, in any event, that the weight of
leaf springs, of which you will need at least two long ones or four
short ones, will be too much. But they may not be too heavy in
reinforced plastics. However, to overcome some other difficulties of
leaning trikes, variable rate springs would be good, and variable rate
damping possibly too, and that is best arranged with helical coil
springs concentric with dampers. Variable in both cases means
progressively disproportional to displacement. Mere static
adjustability is easily arranged by multiple or adjustable mounts.

This is wrong, probably arising from your expectation that any
suspension applied will result in a roll centre above ground. In the

...

So go ahead, design an example front wheel suspension -


I have already; p82 and passim, DESIGNING AND BUILDING SPECIAL CARS by
Andre Jute (B T Batsford, London, 1985). And beside my chair lies a
stack of sheets from more recent considerations. A sketch is always an
aide to clear thinking... (Jobst keeps telling you boys that, and now
I'm telling you too. LOL.)

though I'm not
sure, any "linkage" is necessary. I expect it should be possible to
build a trike with the front wheel outriggers acting like leaf springs.


See above; leaves unless very stiff indeed would have to be
accompanied by a rigid link (the radius stay, if brought in to the
centre line and made not too long might do double duty). The Dutch
Tripod trike http://www.tripod-bikes.com/ has a front beam which may
be either articulated in the middle (swing axle), or a solid axle
pivoting on a centre mount. I cannot quite see on the photographs and
haven't found a description anywhere. The best photograph of the front
axle mount is http://www.tripod-bikes.com/dynamic/.../tripod007.jpg
However, with a bit of expensive engineering it might be possible to
put a single leaf spring inside such a beam whether live or split.
Neat! I don't suppose they did, or they'd crow to high heavens about
such a feat.

I'm not sure about the performance that would have, but from a design
and maintenance point-of-view that would be good...


For that level of understatement they'll make you an honorary
Englishman, Bernhard.

Another thing you mention is "leaning" trikes. Though I understand the
basic principle, I do have a question: the correct amount of "lean"
depends on the actual speed. All of the designs I know of work with
purely mechanical linkage (steering angle proportinal to lean angle).
But that would be wrong, because it only works for a certain speed. So,
unless I'm wrong, "leaning" trikes are no better than trikes with a
fixed front "axle"? Why bother with the weight and mechanics, then?


Because even basic, tilting suspension will corner faster than a rigid
trike. First of all, the correct tilting angle for any given speed is
an on-off switch only in the minds of engineers just out of college;
in real life there is always a range over which just the minuscule
slop in even a well-engineered suspension will adapt to circumstances.
Furthermore, even if on the tilter the suspension's many links are
rock-solid rose-jointed, zero unintended give, a textbook
construction, while it is true that there is a single angle of tilt at
which it will work optimally, it is also true that at tilt angles
either side of optimal at any given speed it will still work better
than upright wheels, if less than optimally when compared to a
theoretically perfectly controlled tilting suspension. (Theoretical
because even Daimler-Benz haven't fully solved the problem of control
-- their F300 Life-Jet still depends on human override.) Hmm, I'm
starting to wonder if one A arm and either your leaf spring or a
really bendy MacPherson strut might not have certain advantages...

I really should emphasize that even a tilting tricycle will likely
never be as fast as a bike around a corner on good roads, and even to
approach what a bicycle can do it will need electronic or manual
controls to vary the tilt beyond what is possible with variable rate
springs, to adapt to road conditions (camber, etc), and that these
additional controls, beyond their own complication and weigh, would
require a possibly expensive learning curve (multiple crashes as the
limits are explored...). it seems to me, with my Calvinist reluctance
to accept vast expense and complication for minuscule speed advantage,
that a fixed tilt, or a mechanically automatically controlled tilt
adjustment (variable rate springs and damping), would be acceptable.
Such a trike would have the advantage of stability on very bad roads
or conditions (and for people with balance problems real or perceived)
and would probably in practice be as fast on corners as all but the
most skilled cyclists.

.....

For the moment I've given up the idea of a tricycle, simply because
the narrow lanes on which i ride would make a wide hard-cornering
tricycle too awkward for cars to pass it in either direction, and a
narrower tricycle which was also high enough to be comfortable just
wouldn't corner fast enough to be satisfactory. The curse of the
speedfreak: the faster bikes are always in the next paddock!

In the last week, in the silage-cutting season, I've several times had
to brake very hard indeed and pull right off the road to let really
big tractors pulling extra-wide trailers filling the whole road pass.
A trike of any description (not even a wide one such as is the logical
outcome of my considertations) would have to stand end-on in the
ditch, or be thrown over the hedge, if the tractor is not to trample
it in situations like that. And around some short, sharp corner, you
have seconds to stop and get out of the way, because those tractors
are really barrelling along, and the farmers driving them are
mindlessly focussed on getting the silage in before the rain falls
again.

The question then arises of where I would ride this trike that I don't
really need but want for the technical interest of the tilting
suspension.

I suspect that what makes the recumbent fanciers so rabidly angry at
my logical and rational dissemination of their obsession is their
unexpressed knowledge that their recumbent bikes and trikes are white
elephants requiring very special circumstances to be of any use
whatsoever, that they are expensive, totally impractical and
unjustifiable toys, especially for owners who spout far-left politics,
as that lot does.
.....


PS: Actually I think Trikes are a question of personal style and as such
you either like them or not. But I cannot project my opinion on someone
else, just like you like racing bikes better than mountain bikes or
whatever you want.


I'm not against tadpole trikes on any engineering principle (as I am
against deltas for more than moderate speed on a good engineering
principle). I wouldn't waste my time if I were. I would rather like to
have a tadpole, if a suitably comfortable and technically interesting
trike can be found. Nor do I force my opinion on anyone. I merely
describe my investigation and the evaluation of commercially available
trikes and others that it may be possible to design and build the
better to meet my requirements. Only those who have an emotional
commitment are offended, and they will be offended by any rational
discussion of their enthusiasm; rational people never have the
slightest problem with what I say.

PPS: There's a number of cyclecar designs available, most based on
tadpole trikes. If you ask me, you could junk press all SUV cars - but
some people seem to like them...


Yes. I wrote to "someone" yesterday that my tilting design, having all
its forces resolved on the centreline, could be made into a tri or
quad cyclecar with a vertically disposed virtually two-dimensional
chassis weighing no more than a stiff diamond-frame. An entire car up
to one liter could be built to weigh in at 200kg. You won't get
leather seats and the air conditioning will be au naturel, but the
tilting will turn the narrow tyres (by car standards, fat by bike
standards, say Big Apple 60-622) necessary for weigh-control into a
huge roadholding advantage.

But in real life, in rainy old Ireland and with the roads being
populated by people who are barely in control of their huge SUVs, if I
ever have to drive again, I'll probably try to find a low mileage
Range Rover from the BMW era: they're the modern equivalent of the big-
bumper Volvos I used to like for my wife and child to be in (even as I
hypocritically for myself bought a Maserati): good visibility, enough
size and weight to tussle with a truck and survive, nimble enough to
get out of trouble, excellent seats and ergonomic controls, reasonable
economy, reliable, low maintenance, not a jumped-up Ford...

Slainte!

Andre Jute
Get a bicycle. You will not regret it. If you live -- Mark Twain

  #18  
Old June 4th 09, 07:36 PM posted to rec.bicycles.tech,alt.rec.bicycles.recumbent
Edward Dolan
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Posts: 14,212
Default THE LOGIC OF TRIKES an outsider's viewpoint by Andre Jute


"someone" wrote in message
...
On 4 June, 19:07, "Edward Dolan" wrote:

[...]

When I first got into bicycling many years ago I read several books about
bicycles that were also gibberish. Let's face it, the mechanical
engineering
types barely know how to write anything that you can make sense of.

Tom Sherman writes extremely well for an engineer. He occasionally uses
too
much engineering jargon, but I suspect he is just testing our patience. I
think he must have taken some liberal arts courses when at college. But
Andre Jute is far more typical of the type. Reading what he writes turns
your brain to mush.


For what Andre was attempting to explain, a picture book would be so
much better. Whether or not he was correct in his explanation of
ideas I'm not too sure. I could follow some of it precisely because I
have considered the problem myself. I also drew a similar conclusion
in that trikes serve a limited market and have little suitability to
go fast without an alternative energy source.


There is a fun factor connected with recumbent trikes that almost everyone
overlooks. But I do agree with you that they are not for speed. It is way
too much work to make them go fast.

I was not fully awake when reading the 'gibberish', so considered that
to be fundamental in my inability to comprehend the text to my
satisfaction. I consider it tooo long to re-apraise, now I'm awake,
in what the author effectively draws the same conclusion as myself.


It is not easy to write an explanation of technically sophisticated content,
but it is not impossible either. You have to severely edit what you have
written and then run it past an idiot. If the idiot can understand what you
have written, then you have written it well.

Regards,

Ed Dolan the Great - Minnesota
aka
Saint Edward the Great - Order of the Perpetual Sorrows - Minnesota



  #19  
Old June 4th 09, 09:53 PM posted to rec.bicycles.tech,alt.rec.bicycles.recumbent
Andre Jute[_2_]
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Posts: 10,422
Default THE LOGIC OF TRIKES an outsider's viewpoint by Andre Jute

On Jun 4, 7:21*pm, someone wrote:

Andre Jute wrote:.
THE LOGIC OF TRIKES
an outsider's viewpoint
by Andre Jute


big snip


Jeff Grippe wrote:
You've got to be kidding! If you ever wanted to convince me not to read
any of your books, you have succeeded. Sheesh!


Ed Dolan whined:
When I first got into bicycling many years ago I read several books

about
bicycles that were also gibberish.


Someone wrote:
For what Andre was attempting to explain, a picture book would be so
much better. *


Oh, I wasn't attempting. I succeeded. You and Bernhard got it, and the
rest of those capable of understanding are silent because I got it
right.

This part of the thread is the whining from those incapable of getting
it because they don't have the brains, like Dolan, or the perfectly
understandable complaints of the more blameless who don't have either
the background or, if they have the background, the attention span to
stay with it until they understand why I want to do something as
counterintuitive, indeed to an auto-engineer as diabolical, as using
parallel equal-length wishbones. (Or, for that matter, any other link
arrangement perverted to give a ground-level roll centre, as briefly
mentioned between Bernhard and me.)

Trick suspensions really aren't for old guys unless they've been doing
it all their lives. And then some ******* like me comes along and
says, "What you know from automobiles is all wrong. Wrong. Wrong.
Chuck it all, and start again only with what your were taught is
incompetent, for we really, really want the body and the wheels of
this vehicle to lean the hell over." That would upset me too, if it
were someone else doing it.

Whether or not he was correct in his explanation of
ideas I'm not too sure. *I could follow some of it precisely because I
have considered the problem myself. *I also drew a similar conclusion
in that trikes serve a limited market and have little suitability to
go fast without an alternative energy source.

I was not fully awake when reading the 'gibberish', so considered that
to be fundamental in my inability to comprehend the text to my
satisfaction. * I consider it tooo long to re-apraise, now I'm awake,
in what the author effectively draws the same conclusion as myself.


It might be worth your while getting to grips with tilting suspensions
-- preferably somewhere with illustrations, as you say -- because they
could allow you to use very narrow, even bicycle "balloon" tyres on a
cyclecar, probably the final weight saving possible until the arrival
of those mythical fuel cells makes the chunky-clunky internal
combustion engine obsolete. Those huge tyres and hefty supporting
wheels are all unsprung weight, and the ratio of unsprung to sprung
weight on a cyclecar is not a happy prospect (except in the ones using
Citroen 2CV wheels, I am told in private mail), but needn't be if it
were a tilter.

Andre Jute
Down with the spoilsport Telemachus!

  #20  
Old June 4th 09, 09:54 PM posted to rec.bicycles.tech,alt.rec.bicycles.recumbent
Andre Jute[_2_]
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Default THE LOGIC OF TRIKES an outsider's viewpoint by Andre Jute

On Jun 4, 5:43*pm, "Jeff Grippe" wrote:
"Andre Jute" wrote in message

...
THE LOGIC OF TRIKES
an outsider's viewpoint
by Andre Jute

big snip

You've got to be kidding! If you ever wanted to convince me not to read any
of your books, you have succeeded. Sheesh!


Sorry about that, Jeff; it probably isn't your fault. This is a tech
newsgroup and I'm writing on a very complicated subject for engineers
who already understand the basics. It would probably help if RBT could
accept illustrations.

Basically, in tilting trikes or quads, you have to unlearn everything
you ever learned about automobile suspensions, because a tilter is an
extremely incompetent suspension deliberately perpetrated... If you
have the suspension basics, and the automotive history, to get your
head around that, and to understand how breaking all the accepted
rules can lead to speed and security, you might follow me; if not, you
will need drawings -- and a good deal of time and effort to understand
what I'm getting at. But RBT can't show you drawings. If it were easy,
there would be a gazillion tilting trikes to choose from at Wally's
World.

If it is any consolation, my book explaining, inter alia, automobile
suspensions to hobbyist car designers and builders altogether ignores
tilting suspensions as far, far too esoteric and difficult to be
included even in a "comprehensive survey".

****

However, if we abstract all the complications and qualification and
reduce a tilting suspension to the fishbone of necessity (that's a
pun, don't sweat it), yes, you can imagine what I'm talking about. Try
this:

Imagine the digit 8 made up of four long equal-length laths of wood
and three short equal-length laths of wood, pinned at all joints so
that the thing is a folding mechanism rather than a rigid structure.

Turn your 8 sideways. Now you have three parallel uprights in a row,
and two parallel longer pieces per side connecting the central upright
to each outside upright on that side.

The central upright represents the chassis and the rider, in short the
trike's entire payload.

The two outer uprights represent the wheels.

Two parallel arms from the centre payload to each wheel are the
suspension wishbones, seen from the side.

In a corner the payload will tilt.

On your figure 8, tilt the payload, represented by the central
upright. The wheels tilt, pulled by the links.

Reset to level. Tilt the payload, represented the other way The wheels
tilt, pulled by the links.

That's it, a tilting suspension. All the rest is detail and compromise
to make it work in the real world.

HTH.

Andre Jute
"Cycling wisdom" is an oxymoron
 




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