John Howard's land speed record
Jobst Brandt
wreck.bike. I saw the "bicycle" (two wheels) at InterBike when it was
news. The bicycle had a gear ratio so high it could not be pedaled
forward at any speed on a smooth flat surface. It had compound gear,
basically a 52-13 (4x) times 52-13 (4x), an 16:1 ratio.
The bicycle was towed up to the maximum speed Howard's cadence could
follow and to make sure he didn't drift off into the wind eddies, his
bicycle had the engine throttle on the hand grip so he could maintain
minimum distance to the limit roller in the wind screen.
To me the whole thing was an advertising sham, and many people
believed every bit of it.
http://www.canosoarus.com/08LSRbicycle/LSR%20Bike01.htm
This has all been discussed here on this newsgroup at length.
Where've you been?
Jobst Brandt
Jobst Brandt
> I take it the people commenting on his ride are newcomers to
> wreck.bike. I saw the "bicycle" (two wheels) at InterBike when it
> was news. The bicycle had a gear ratio so high it could not be
> pedaled forward at any speed on a smooth flat surface. It had
> compound gear, basically a 52-13 (4x) times 52-13 (4x), a 16:1
> ratio.
> The bicycle was towed up to the maximum speed Howard's cadence could
> follow and to make sure he didn't drift off into the wind eddies,
> his bicycle had the engine throttle on the hand grip so he could
> maintain minimum distance to the limit roller in the wind screen.
> To me the whole thing was an advertising sham, and many people
> believed every bit of it.
> http://www.canosoarus.com/08LSRbicycle/LSR%20Bike01.htm
> This has all been discussed here on this newsgroup at length.
> Where've you been?
I suppose I should add that this is not a wind break behind which he
is riding but an aerodynamic push. As I said, the gear was so high it
would not propel the bicycle in still air at any speed. The eddies
closing in behind the "wind screen" are like the ones in convertible
cars that make long hair fly forward into the windshield of the car.
For that reason, modern convertibles use a mesh wind break behind
passengers to prevent messing up their coif.
Jobst Brandt
carl...@comcast.net
Dear Jobst,
Er, where have you been?
As has been previously and repeatedly explained to you . . .
A) No, the land speed bikes are not impossible to pedal forward on
flat surfaces:
http://www.canosoarus.com/08LSRbicycle/LSR%20Bike02.htm
That's a 138 mph land speed record bicycle being pedaled forward
around a parking lot.
B) No, Howard was not towed up to "the maximu speed" that hiss
"cadencee could follow"--he was towed up to only 60 mph before he
disengaged the tow cable and accelerated about 90 mph in the draft to
152 mph.
C) No, it wasn't a 52x13 double reduction. Howard used a 70x13 and
52x16 double reduction, for a 17.5 overall sprocket ratio.
Anyone who has "Racing the Wind" and "Pushing the Limits" can verify
these previously points, which have appeared in threads that you
stubbornly ignore.
Cheers,
Carl Fogel
dusto...@mac.com
Thanks Carl.
Got anything on the "it's John Howard's fault and his alone that we
have lawyer lips"? (I mean, some forks have lawyer lips. Mine are
human))
Gracias.
--D-y
Andre Jute
So nice of you to ask, Jobst. While that discussion was winding its
abrasive way around the personalities on RBT, I was out riding
downhill behind a truck. I believe that in the States you call it
motor pacing.
Andre Jute
The only diet that works is exercise
carl...@comcast.net
Dear D,
Yes, was one of the witnesses who testified in the trial that led to
lawyer lips.
It was about as bad as Jobst's continuing nonsense about bicycles
wafting effortlessly along behind pace cars at 150+ mph, like hair
blowing forward in convertibles.
Oh, I forgot one other example of Jobst's current display of willful
ignorance about land speed records . . .
D) No, Howard's pace car had no "limit roller" in the back. Anyone
familiar with the land speed records knows that rollers weren't
used--heck, just look at any side photo of the Howard or Rompelberg
speed runs. Jobst is just imagining things that he's seen on the backs
of Derny pacers.
Cheers,
Carl Fogel
Cheers,
Carl FOgel
z
Against a flat object perpendicular to the front wheel, like a bumper,
you don't really need a roller. You can scuff the bumper quite
comfortably and safely (you can bump them relatively hard without a
problem), whereas you don't really want to hit the fender of a derny off
center and have your front knocked sideways, which will throw you the
other direction.
Demi-fonds (you don't generally see a roller on an traditional derny)
use rollers at varying distances from the motorcycle as a speed limiter
by keeping riders farther away from the pacer to reduce the draft and
keep speed manageable for the particular size of the track (smaller
tracks need slower speeds).
The only benefit of a roller on Howard's pace car would be to minimize
the scuffing of the tire tread on his bicycle's front wheel.
Tosspot
<snip>
> So nice of you to ask, Jobst. While that discussion was winding its
> abrasive way around the personalities on RBT, I was out riding
> downhill behind a truck. I believe that in the States you call it
> motor pacing.
Heh! We used to do that behind buses when we were kids. Right up to
the point I rode into the back of one :(
Tom Sherman °_°
The best draft I ever had was behind a hay wagon being pulled by a
pick-up truck at about 40 kph.
--
Tom Sherman - 42.435731,-83.985007
thirty-six
wrote:
I tried that and got my eyes full of dust. Whenthe wind is blowing
with you, the draught isn't needed.
Frank Krygowski
wrote:
>
> I once ran out of fuel on the M6, slipstreaming a truck (I was on a
> motorcycle)..
> I didn't even know until I tried dropping back to take the exit to the
> services, and had to use the brake because the throttle was already
> closed all the way. Once I fell out of the slipstream, I had to
> declutch and coast.
> I have absolutely no idea how far I rode on fresh air.
??
Are you saying the motorcycle was in gear, out of fuel, and even with
the throttle closed the aero forces were pulling the motorcycle
forward at full speed?
- Frank Krygowski
thirty-six
No, it was the Morris Marina on the other end of the trailer's drawbar
which did the pulling.
carl...@comcast.net
Dear Frank,
Well, there was the extra inertia of the passenger:
"When I and my mate on the back realised what had happened, we got
such a fit of the giggles that we couldn't push the bike up to the
pump for about 15 minutes :)"
Cheers,
Carl Fogel
dusto...@mac.com
> I take it the people commenting on his ride are newcomers to
> wreck.bike.
Not hardly a newcomer here. You knew that, too.
I saw the "bicycle" (two wheels) at InterBike when it was
> news. The bicycle had a gear ratio so high it could not be pedaled
> forward at any speed on a smooth flat surface. It had compound gear,
> basically a 52-13 (4x) times 52-13 (4x), an 16:1 ratio.
>
> The bicycle was towed up to the maximum speed Howard's cadence could
> follow and to make sure he didn't drift off into the wind eddies, his
> bicycle had the engine throttle on the hand grip so he could maintain
> minimum distance to the limit roller in the wind screen.
>
> To me the whole thing was an advertising sham, and many people
> believed every bit of it.
>
> http://www.canosoarus.com/08LSRbicycle/LSR%20Bike01.htm
That very short "feature" shows: 1) No "roller"; there is a "crash
bar" at handlebar height, but no roller for the front wheel of the
bike to touch (maybe they were smarter than to try a roller at speeds
in excess of 150mph?), and 2) the front wheel of the bike is well
behind the short "lip" or enclosure at the back of the fairing-- IOW,
Howard is riding well away from the 'liner, with his head 3' or more
away from the back (rearmost part) of the fairing.
The throttle control on Howard's handlebar? I'd forgotten about that.
Great idea, there.
If you don't like John Howard and even if you might have good reason
not to "like" John Howard, Jobst, he still went 152 and change behind
that Bonneville streamliner. And you could get the details right-- for
another thing, that picture you linked to shows the side "extension"
on the fairing to be cut away at the bike's wheel level so that there
is hardly any extension there at all.
For another nuther thing, the bike had a vertically oriented crash bar
situated about a foot forward of the top of the headset, and the crash
bar on the car stuck out past the rear of the car a foot and a half or
more at the height it was located, guessing from the slanted
perspective of the photo.
> This has all been discussed here on this newsgroup at length.
> Where've you been?
Here since '01 at least. Well, I can see how that would make one a
newcomer in the perspective of a guy who fought the dinosaurs with a
spiked club.
<g>
--D-y
thirty-six
Waiting to see the photographs.
carl...@comcast.net
<dusto...@mac.com> wrote:
>On Feb 6, 5:57锟絧m, Jobst Brandt <jbra...@sonic.net> wrote:
>> I take it the people commenting on his ride are newcomers to
>> wreck.bike.
>
>Not hardly a newcomer here. You knew that, too.
>
> 锟絀 saw the "bicycle" (two wheels) at InterBike when it was
>> news. 锟絋he bicycle had a gear ratio so high it could not be pedaled
>> forward at any speed on a smooth flat surface. 锟絀t had compound gear,
>> basically a 52-13 (4x) times 52-13 (4x), an 16:1 ratio.
>>
>> The bicycle was towed up to the maximum speed Howard's cadence could
>> follow and to make sure he didn't drift off into the wind eddies, his
>> bicycle had the engine throttle on the hand grip so he could maintain
>> minimum distance to the limit roller in the wind screen.
>>
>> To me the whole thing was an advertising sham, and many people
>> believed every bit of it.
>>
>> 锟絟ttp://www.canosoarus.com/08LSRbicycle/LSR%20Bike01.htm
Dear D,
Just for fun, a few calculations.
Howard weighed ~170 pounds, wore ~12 pounds of leathers and helmet,
and rode a 45~46 pound bike that hit 152 mph on the last run through
the speed traps after casting off the tow at 60~65 mph.
Howard used wide, smooth tires inflated to 70 psi on the Salt Flats.
(Bonneville's surface is notorious for having noticeably higher
rolling resistance than pavement. On the other hand, the thinner air
at 4320 feet helps the unpaced vehicles.)
Rolling resistance varies with speed, but the general equation for
power at a given speed works fairly well:
watts = (mass in kg) x (g in n/kg) x crr x (v in m/s)
(170+12+45)/2.2 x 9.81 x crr x (152*0.447)
103 kg x 9.81 x crr x 68 m/s
crr watts
0.0050 343
0.0060 412
0.0070 481
0.0080 550
As anyone would expect, Howard (who rode in the Olympics) had to pedal
hard just to overcome rolling resistance when the wind drag was
effectively eliminated.
I'd love to see some calculations about what kind of steady tail wind
acting on the back of a bicyclist is needed to provide the 350~550
watts needed to overcome that kind of rolling resistance.
It's probably a bit more than any wind that blows long hair foward in
a convertible. Strands of hair have somewhat different aerodynamic
characteristics than bicyclists, possibly due to the ratio of surface
area to mass.
:)
Cheers,
Carl Fogel
dusto...@mac.com
> Waiting to see the photographs.
There's one photo of the car and bike in action at the given link.
--D-y
dusto...@mac.com
> (Bonneville's surface is notorious for having noticeably higher
> rolling resistance than pavement.
Not glassy smooth, either, from what I've read.
IMS, I've seen in-car camera film that showed a fair amount of in-car
vibration going on.
> As anyone would expect, Howard (who rode in the Olympics) had to pedal
> hard just to overcome rolling resistance when the wind drag was
> effectively eliminated.
>
> I'd love to see some calculations about what kind of steady tail wind
> acting on the back of a bicyclist is needed to provide the 350~550
> watts needed to overcome that kind of rolling resistance.
>
> It's probably a bit more than any wind that blows long hair foward in
> a convertible. Strands of hair have somewhat different aerodynamic
> characteristics than bicyclists, possibly due to the ratio of surface
> area to mass.
>
> :)
Well, that record had some cachet (hence value to advertisers <g>) and
I don't remember anyone immed. stepping up to the plate to better it.
Scuse me while I don't look that up but Howard's record was set in
1985, Rompelberg's in 1995, which I believe still stands.
One tiny reason might be that going say, anything over 150 mph on a
bicycle is a hairy ride. Think? I haven't read of Rompelberg's trip
over the salt but I seem to remember Howard having a Hail Mary moment
or two. --D-y
Chalo
>
> Phil W Lee wrote:
> >
> > I once ran out of fuel on the M6, slipstreaming a truck (I was on a
> > motorcycle)..
> > I didn't even know until I tried dropping back to take the exit to the
> > services, and had to use the brake because the throttle was already
> > closed all the way. Once I fell out of the slipstream, I had to
> > declutch and coast.
> > I have absolutely no idea how far I rode on fresh air.
>
> ??
>
> Are you saying the motorcycle was in gear, out of fuel, and even with
> the throttle closed the aero forces were pulling the motorcycle
> forward at full speed?
I was thinking it must have been a two-stroke motorcycle. No valves
means a whole lot less engine braking, variable according to overall
flow restriction.
(Not that all two-stroke engines lack valves. I don't want to get
into that again.)
Chalo
Lou Holtman
> On Feb 7, 3:09 pm, carlfo...@comcast.net wrote:
>
>> (Bonneville's surface is notorious for having noticeably higher
>> rolling resistance than pavement.
>
> Not glassy smooth, either, from what I've read.
> IMS, I've seen in-car camera film that showed a fair amount of in-car
> vibration going on.
I visited the site when I passed by and was suprised about the roughness
of the surface and thought why on earth is this a good place to set
speed records.
Lou
Frank Krygowski
> Frank Krygowski wrote:
>
> > Phil W Lee wrote:
>
> > > I once ran out of fuel on the M6, slipstreaming a truck (I was on a
> > > motorcycle)..
> > > I didn't even know until I tried dropping back to take the exit to the
> > > services, and had to use the brake because the throttle was already
> > > closed all the way. Once I fell out of the slipstream, I had to
> > > declutch and coast.
> > > I have absolutely no idea how far I rode on fresh air.
>
> > ??
>
> > Are you saying the motorcycle was in gear, out of fuel, and even with
> > the throttle closed the aero forces were pulling the motorcycle
> > forward at full speed?
>
> I was thinking it must have been a two-stroke motorcycle. No valves
> means a whole lot less engine braking, variable according to overall
> flow restriction.
Hmm. If it were a "mix-oil-with-gasoline" two-stroke engine, it would
be running unlubricated. That's a recipe for engine seizure. But I
guess one with an oil injection pump might survive.
But it still sounds - um - amazing to me.
- Frank Krygowski
dusto...@mac.com
wrote:
> Correct - steady 60mph.
Info please: what kind of truck?
A semi (tractor plus trailer) is about 50' (15.25m) long, much taller
and at least a little wider than Howard's Bonneville streamliner; the
airflow comparison beneath those vehicles is a guess at this point.
I've drafted on (my favorite) dump trucks (more or less a semi tractor
with the dump bed on a solid chassis, no pivot) and if you get right
on the pumpkin (rear axle differential casing), the draft is pretty
clean at speeds up to about 50 or so <g>. But you still have to pedal
hard, you're not getting dragged along, loafing.
--D-y
AMuzi
>>> (Bonneville's surface is notorious for having noticeably higher
>>> rolling resistance than pavement.
> dusto...@mac.com schreef:
>> Not glassy smooth, either, from what I've read.
>> IMS, I've seen in-car camera film that showed a fair amount of in-car
>> vibration going on.
Lou Holtman wrote:
> I visited the site when I passed by and was suprised about the roughness
> of the surface and thought why on earth is this a good place to set
> speed records.
Mostly, good sight lines and no pedestrians ( or other
impedimenta).
--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971
carl...@comcast.net
Dear Frank,
Oh ye of little faith!
Just imagine a transmission so inefficient that it failed to transmit
any of the braking power of an unpowered engine at 60 mph to the rear
tire.
Heck, with a _really_ inefficient transmission, say -95% as opposed to
+85%, the engine braking would actually _push_ the motorcycle forward!
***
As for seizure . . .
A friend who should have known better once decided to coast down the
steep mountain road from the trailhead to where he'd parked the
trailer for his Honda trials machine.
For the best possible mileage, he put the motorcycle in neutral and
killed the engine.
Too late, he remembered that the countershaft sprocket was pressure
lubricated by the engine--which wasn't running and provided an
expensive lesson in seizure.
Cheers,
Carl Fogel
carl...@comcast.net
Dear D & Lou,
Some of the camera shake is due to enormous engine vibration, and some
of it is just what you get going over any real surface at high
speeds--think of a passenger jet taking off on a "smooth" concrete
runway.
But some camera shake in Salt Flat films is due to snowplowing on a
miniature scale through the salt at fantastic speeds--the vehicles are
covered with salt "spray" at the end of a typical run.
A huge drag is run daily over the slow and the fast tracks to smooth
the course, but even tiny inconsistencies cause a rough ride at over
200 feet per second.
Even scraped, the Salt Flats are worse in terms of rolling resistance
than pavement.
A curious complaint is that traction suffers, too. It's weird to worry
about traction on what looks like a perfectly good flat surface, but
the reduced traction on salt means less power moving you forward.
***
Why use the Salt Flats?
They're almost perfectly flat after they dry up every year, and
they're big enough for incredible run-up and roll-out distances.
Another advantage is that no one complains about the noise.
The thin air helps, too. Going from sea level to 4320 feet is worth a
little over 1 mph to a bicyclist on the drops at 200 watts.
A strange advantage that somewhat offsets the rolling resistance and
traction problems is that the salt stays damp (even though it's hard)
and cools the high-speed tires better than pavement, reducing tire
failures. The salt flats seem dry only as long as you don't kneel on
them--the damp patch on the knee of your pants is quite surprising.
***
For comparison, Battle Mountain is a paved road on a permanently
dried-up sea-floor.
Route 305 at Battle Mountain is about as flat and long a stretch of
pavement as can be found for people who like a 5-mile run-up to the
200-meter speed trap. with a 170-foot drop under 0.66% grade overall:
http://www.wisil.recumbents.com/wisil/whpsc2009/whpsc_site.htm
If you're thinking of renting an airport for a day, think again--the
longest runways in the world are under 4 miles long:
http://en.wikipedia.org/wiki/List_of_longest_runways
The pavement helps the fully-faired bicycles that are so sensitive to
rolling resistance and would suffer on salt flats. The tires aren't
putting even 1 horsepower into the ground, so they don't suffer from
the lack of cooling provided by the damp salt.
And Battle Mountain is about 4500 feet above sea level, which helps
vehicles that are all about wind drag.
Cheers,
Carl Fogel
Jay Beattie
You have to have good leg speed or a bungee cord. It's not a totally
free ride, or at least I have never encountered a truck that simply
pulled me along without pedalling. That would require a Star Trek
tractor beam, IMO. I had a coach who used to like to do motor pacing
using a station wagon, which was a so-so wind break. We got pulled
over two or three times by rural sheriffs for "following too close."
Lectures but no tickets. -- Jay Beattie.
Jobst Brandt
>> rolling resistance than pavement.
> Not glassy smooth, either, from what I've read. IMS, I've seen
> in-car camera film that showed a fair amount of in-car vibration
> going on.
The high speed course is about as smooth as a salt lake can be made.
The speed records are not run on an old dirt road and course is wide
enough that there aren't a lot of spin-outs.
>> As anyone would expect, Howard (who rode in the Olympics) had to pedal
>> hard just to overcome rolling resistance when the wind drag was
>> effectively eliminated.
>> I'd love to see some calculations about what kind of steady tail wind
>> acting on the back of a bicyclist is needed to provide the 350~550
>> watts needed to overcome that kind of rolling resistance.
>> It's probably a bit more than any wind that blows long hair forward
>> in a convertible. Strands of hair have somewhat different
>> aerodynamic characteristics than bicyclists, possibly due to the
>> ratio of surface area to mass.
> Well, that record had some cachet (hence value to advertisers <g>)
> and I don't remember anyone immed. Stepping up to the plate to
> better it. 'Scuse me while I don't look that up but Howard's record
> was set in 1985, Rompelberg's in 1995, which I believe still stands.
> One tiny reason might be that going say, anything over 150 mph on a
> bicycle is a hairy ride. Think? I haven't read of Rompelberg's
> trip over the salt but I seem to remember Howard having a Hail Mary
> moment or two.
I saw the vehicle close up and talked to Howard and others at the bike
show. Because controlling the pace car speed is hard to assess from
the driver's seat, Howard held the throttle while the back-draft kept
him with his bumper bar against the restraint, equivalent to the limit
roller of earlier times. With a 16:1 gear ratio, the speed at those
miles per hour, cannot be affected so he kept the back draft propelled
"bicycle" in contact with the bumper bar.
Look carefully at the picture and you'll see the double reduction
chain drive with identical ratios. Just trying to propel a bicycle
with no speed with that arrangement doesn't work. The ratio was
selected to be within the achievable cadence limit at the speed
anticipated and it was changed for various runs until the speed was
reached.
Jobst Brandt
carl...@comcast.net
Dear Jobst,
Interesting . . .
Your new memories don't quite match your previous posts:
http://groups.google.com/group/rec.bicycles.tech/msg/144b52e86d424541
Now you're claiming to have talked to Howard, not his team, with all
sorts of interesting additions and nonsense showing that you still
don't understand that the tow was dropped at ~60 mph, just as it was
on other land speed records.
And Howard's written account says nothing at all about changing
gearing--but you've never bothered to read that, have you?
Nor taken into account the written records of Abbott and Rompelberg.
Heck, you don't even look at the photos showing the bike off the
bumper bar--which you at least now realize wasn't a roller bar.
Cheers,
Carl Fogel
carl...@comcast.net
<phil(at)lee-family(dot)me(dot)uk> wrote:
>Chalo <chalo....@gmail.com> considered Sun, 7 Feb 2010 14:15:01
>It was a Honda CB250NA, and in 6th gear there was very little engine
>braking.
Dear Phil,
The Honda CB250NA's top speed was about 135 kmh/84 mph at 9,000 RPM:
http://www.motorcyclesurvey.com/reviews/honda/cb250n/r687/comments/
It was a 250cc twin-cylinder 4-stroke motorcycle:
http://www.motorbookguy.com/Honda_CB250_CB400_N_Super_Dreams_Repair_Manual_1_p/m540.htm
The slightly earlier CB250N had a 9.4 to 1 compression ratio:
http://www.motorcyclespecs.co.za/model/Honda/honda_cb250n%2079.htm
Hard to imagine a twin-cylinder 4-stroke with a 9.4 to 1 compression
ratio "having very little engine braking" at ~60 mph/6,500 RPM when it
was out of gas.
Cheers,
Carl Fogel
dusto...@mac.com
> I had a coach who used to like to do motor pacing
> using a station wagon, which was a so-so wind break. We got pulled
> over two or three times by rural sheriffs for "following too close."
> Lectures but no tickets.
A local picker/singer/funny guy, Sammy Alred, told a joke about a
great defense lawyer who got a charge of sodomy (this is Texas)
reduced to "following too close".
My old coach had a Honda Hawk (500 twin) with a windscreen (just an
upright screen, no fairing), and a throttle peg.
Much, much safer than a car, due to actually being able to see the
road while motorpacing, and he could see the road better than a motor
vehicle operator can, too. Also great practice at sniffing out the
draft while following a smaller, two-wheeled vehicle, which has served
me well since the draft is not always "where it should be". No
incidents with Johnny Law; we had a nice long stretch of little-used
blacktop "section road" near a highway that was cornfield-flat, just a
little undulation. I wouldn't be able to go nearly as fast these days
but motorpacing there would still do wonders for my riding. Ah,
"sprint for that mailbox", beat the motorcycle by a foot at the line
(practicing incontestable race/prime finishes) with a throw, and then
the really hard part-- getting back on at 37mph (other guys in my club
went faster <g>) and staying there until the next random sprint was
called. What don't kill you makes you strong! (Oh For the Days!)
Funny, too, with a 6' 4" rider, that bike had a fine draft, pretty
close to or maybe even better than the few cars I've drafted. Probably
because I'd give the cars a little more room (not being able to see
the road and all), while the bike I would ride very tight on,
including using the roller bar it had on the back. Which could, in
hindsight, probably have been just a nice smooth "bash bar", serving
mainly as a last defense against getting into the rear wheel of the
MC, whether by operator error or a blast of wind.
Whatever, I never went more than about a third of Howard's speed and
even behind the huge hind end of dump trucks-- and a larger, stone-
carrying variation of hauler (I used to hang around the quarry
entrance/exit road to hop on those), I had to pedal. Yes, the effort
was reduced, but the sensation was maybe more like riding rollers than
pavement, certainly not a free ride-- and if you loaf, back and out
you go! --D-y
Jobst Brandt
records. Any road vehicle with a flat back, highway transport, van or
station wagon, has its rear surface covered with debris, water, or
snow, that the eddy currents of static air on the route to blow
forward onto the vehicle. For that reason, most of these with a rear
window have a windshield wiper and washer to clean off the material
that was blown forward on to the rear of the vehicle.
Winds screens for record attempts are not left to nature. They are
shaped to enhance the effect and it does. To avoid that effect, most
aircraft have tapered trailing edges to prevent air lift-off and eddy
currents that use propulsion power to form. That a bicyclist can get
push from a motor-pace vehicle should be apparent from these
consideration. The faster the vehicle the greater the push and that
is why Howard was towed up to a speed that would give reasonable push.
The test course was not long enough to tow to a lesser speed. I don't
know how fast that speed was for the final record although much is
mentioned about less than 100mph.
Jobst Brandt
carl...@comcast.net
Dear D,
Just a handy place to hang these.
Windscreen:
http://imageevent.com/dernysportuk/stayersukpastyears?p=32&b=-1&m=-1&c=3&w=4&s=1&n=1&l=0&z=3
No windscreen:
http://imageevent.com/dernysportuk/stayerpictures?p=1058&n=1&m=-1&c=2&l=0&w=4&s=0&z=2
Better view of the gearing:
http://imageevent.com/dernysportuk/stayerpictures?p=1056&n=1&m=-1&c=2&l=0&w=4&s=0&z=2
And you're right, there's no such thing as a free ride, despite what
people imagine, so the record seekers used all sorts of tricks:
http://i45.tinypic.com/m80ebn.jpg
As the book cover shows, Howard and Rompelberg used rear wheel covers
to cut the wind drag on the spokes as the wheels spun at 150+ mph in
the draft. Front disks weren't used because of fears about handling.
Cheers,
Carl Fogel
carl...@comcast.net
Dear Jobst,
I suspect that you're being silly.
Water, snow, and salt have rather obviously different aerodynamic
characteristics than 220 pounds of bicycle and bicyclists. That's why
they fly up in the air, while the bicyclist stays firmly on the
ground. Light particles and mud swirling around behind a car are
hardly the same as a human body.
The accounts of the three Salt Flats record holders all mention that
the tow was released at ~60 mph--why keep pretending that this is a
mystery?
What on earth do you mean by "the test course was not long enough to
tow to a lesser speed"?
This kind of incoherence is a feature of most of your posts on the
subject.
Why keep fixating on just Howard, since you seem to know almost
nothing about his record?
Why not start telling us about Abbott and Rompelberg, too? Or the 100+
mph riders like LeTourneur, Le Grys, and Meiffret?
Cheers,
Carl Fogel
al williams
I used to commute 20 mi. on US 30 in eastern Pennsylvania, and would
motorpace trucks frequently. The airflow from standard truck trailers
came over the roof and curled down and forward, so that my sweat on
hot days would blow forward under the trailer-- my airspeed was
negative. Airflow had to be forward under the truck, then out the
sides between the tractor wheels and the trailer wheels. So much for
"suction" when passed by high-speed trucks, but that is a different
topic. I could manage my effort by moving laterally relative to the
truck-- least effort centered behind the truck, gradually more and
more effort required as I would move toward the side edge of the
truck. There was still a good draft when positioned a bit outboard of
the side of the truck. I always had to pedal-- never was completely
pulled by the airflow.
With a headwind, air would come toward me between the trailer's wheels
until we got up to about 15 mph, then the wind from below the trailer
floor would stop and I would get a good draft.
Car carriers gave the best draft at moderate speed because their low
floors prevented airflow in either direction when centered on the
trailer.
Dump trucks didn't have the negative airspeed situation.
dusto...@mac.com
Thanks!
How did you hop on-- entrance ramps?
Male Answer Syndrome: maybe dump trucks don't pull air forward because
they are so much shorter than a semi trailer?
Once while drafting a quarry truck, I was getting close to a city
limits sign and wanted to pull a real coup-- yup, winning the "sprint"
against the truck. Stuck my nose out carefully, yanked it right back
in, in order not to head-on with the county cop coming the other way.
It was close, too. I thought he'd throw me in the slammer for scaring
him, at least, but nothing happened except I dialed back the riding-
crazy-in-the-streets thing.
--D-y
Frank Krygowski
>
>
> And you're right, there's no such thing as a free ride, despite what
> people imagine, so the record seekers used all sorts of tricks:
> http://i45.tinypic.com/m80ebn.jpg
Good view of the tow cars.
Now, as I recall from back when I was interested in such things: the
lip or spoiler (like on the top of Howard's car) had the purpose on
all Kamm-back LeMans cars of trapping a stable, horizontal-axis vortex
behind the car, for stability.
More detail: The most low-drag tail for a fast car would be a long
gradual taper to a point or line. The taper can't be too sharp, or
air won't follow the contour. But long gradual tapering tails are
impractical on road racers.
Kamm came up with the idea of using the ideal gradual taper for as far
back as was practical, then chopping it off. Air flow was already
headed along that ideal taper, so to speak, so when it lost the
support surface it still tended to follow the same path. Drag was not
as low as for a "perfect" tail, but it was lower than the alternative,
a tail with excessive taper.
But random vortices did form in that low-pressure area behind the
chopped tail. Those caused stability problems as the vortexes flopped
back and forth from one side to another.
Then someone put a fence or lip on the top rear edge, and that fixed
the stability. Supposedly, there was now one large, stable vortex. A
bit more drag than without the lip, but so much more stability that it
was worth it.
Now look at Howard's rig. That vortex would likely be a cylinder of
air rotating on a horizontal axis, going counterclockwise in that
view, passing over his head on the way back, then returning behind
him. The effect would be a push on the butt. And if the faster the
car goes, the harder that push.
At low speeds, the effect is enough to blow a convertible rider's hair
forward, or to blow road dust onto the rear window of a flat-backed
car. That means these vortices have a forward component greater than
the speed of the vehicle. At over 100 mph ground speed, the push
would be much, much more.
I'd love to know what would have happened if Howard did have a
freewheel on the bike. I think it's possible he could have just
coasted.
- Frank Krygowski
Jay Beattie
> On Mon, 8 Feb 2010 08:08:34 -0800 (PST), "dustoyev...@mac.com"
>
> No windscreen:
>
> http://imageevent.com/dernysportuk/stayerpictures?p=1058&n=1&m=-1&c=2...
>
> Better view of the gearing:
>
At the above link, the guy who is holding on to the two bikes looks
like he had his head replaced -- pre-Photoshop. -- Jay Beattie.
thirty-six
getting drawn into the vehicle in front on level ground can occur at
40mph. I remember pulling off away from a vehicle because I had my
brakes constantly on and I was overheating. I forget what vehicle it
was, it was back in my days of invincibility (must have been wearing
my magic white diadora ankle socks).
thirty-six
> carlfo...@comcast.net considered Mon, 08 Feb 2010 00:05:04 -0700 the
> perfect time to write:
>
>
>
> >On Mon, 08 Feb 2010 06:12:54 +0000, Phil W Lee
> ><phil(at)lee-family(dot)me(dot)uk> wrote:
>
> >>-0800 (PST) the perfect time to write:
>
> >>>Frank Krygowski wrote:
>
> >>>> Phil W Lee wrote:
>
> >>>> > I once ran out of fuel on the M6, slipstreaming a truck (I was on a
> >>>> > motorcycle)..
> >>>> > I didn't even know until I tried dropping back to take the exit to the
> >>>> > services, and had to use the brake because the throttle was already
> >>>> > closed all the way. Once I fell out of the slipstream, I had to
> >>>> > declutch and coast.
> >>>> > I have absolutely no idea how far I rode on fresh air.
>
> >>>> ??
>
> >>>> Are you saying the motorcycle was in gear, out of fuel, and even with
> >>>> the throttle closed the aero forces were pulling the motorcycle
> >>>> forward at full speed?
>
> >>>I was thinking it must have been a two-stroke motorcycle. No valves
> >>>means a whole lot less engine braking, variable according to overall
> >>>flow restriction.
>
> >>>(Not that all two-stroke engines lack valves. I don't want to get
> >>>into that again.)
>
> >>It was a Honda CB250NA, and in 6th gear there was very little engine
> >>braking.
>
> >Dear Phil,
>
> >The Honda CB250NA's top speed was about 135 kmh/84 mph at 9,000 RPM:
> >http://www.motorcyclesurvey.com/reviews/honda/cb250n/r687/comments/
>
> probably only with favourable wind or gradient).
>
>
>
> >It was a 250cc twin-cylinder 4-stroke motorcycle:
>
>
> >The slightly earlier CB250N had a 9.4 to 1 compression ratio:
> >http://www.motorcyclespecs.co.za/model/Honda/honda_cb250n%2079.htm
>
>
> >Hard to imagine a twin-cylinder 4-stroke with a 9.4 to 1 compression
> >ratio "having very little engine braking" at ~60 mph/6,500 RPM when it
> >was out of gas.
>
> much engine there!
> It didn't slow down much when it ran onto reserve - I never had to
> declutch in order to coast far enough to switch over if I was on the
> open road.
> You could also hit the kill switch for a couple of seconds to get rid
> of tailgaters - when you switched back on again it gave a great
> backfire :)
Cleared out the soot, no doubt.
dusto...@mac.com
A convertible auto cockpit's air swirls around, not just flowing
forward. That's why hair gets so messed up. There's enough energy in
the air currents that BMW and probably others put clips on seat back
fronts to hold shoulder belts down; unclipped, the belts do rattle
irritatingly. They don't pull forward to the limit of slack and stay
suspended.
I've never felt more than a buffeting while riding in a convertible,
at least up to 75mph or so. Twice that fast, who knows. But,
interestingly, putting the side windows up drastically lowers
buffeting (one reason convertible drivers put the side windows on
sunny, cold days). Leading to a guess that Howard and Rompelberg dealt
with possibly large amounts of buffeting, which leads to questions
about how much "push" they did benefit from.
Who knows how coherent the wind blast is on one of these bicycle
record cars? Total energy available might be very roughly estimated by
comparing an "ideal" tapered-tail car with its Kamm-cutoff
counterpart. There might be figures available for the Howard car,
which IMS was a successful Bonneville streamliner, before and after
addition of the fairing.
Carl, is that info in Racing the Wind? It seems to me I read some
discussion about that.
Well, if you're not going to believe Howard's account of his trip,
what about Rompelberg's account of his?
Carl?
At the very least, sitting on a freewheeling bicycle seat while going
152 or 167mph via a giant hand pushing you in the back would still be
a mighty hairy trip-- at least the first time or two <g>. Especially
on what is essentially a dirt road, even if "dragged" for smoothness.
--D-y
carl...@comcast.net
Dear Jay,
But the sprockets look natural, right?
Cheers,
Carl Fogel
carl...@comcast.net
Dear Frank,
The breeze that will blow your hair or dust particles forward will not
even begin to push a 220+ lb bicycle and rider forward against the
rolling resistance of the tires at the same speeds.
You want to sit in the back of a pickup truck doing 100 mph sometime.
The turbulence, which is rather random, is not going to push a bicycle
and rider up to 100 mph.
Heck, according to the sillier theories floating around here, you
could just toss a basketball out the back of a car at 100 mph and it
would follow you for miles--the basketball has a far greater surface
to mass ratio than a bicycle, yet somehow no one has filmed this
happening.
We're off in the bizarre world where people claim that the draft of an
ordinary truck on a highway is enough to drag a hefty motorcycle with
_two_ riders against the drag of a 250cc twin-cylinder 4-stroke engine
doing about 6,000 RPM with no gas!
Remember, Jobst's original claim a few years ago was that it was
impossible for Mile-A-Minute Murphy to do any useful pedal work in the
draft of a train at a mere 60 mph, despite Sam Whittingham doing over
80 mph without any draft at all. As usual, he simply ignored posters
pointing out roller riders routinely exceeding 60 mph.
Similarly, Jobst's original claim was that the chains could be removed
and that it was all a sham--the riders were all towed up to record
speed and then sat in the draft, faking it. This was despite endless
reports that all the 100+ mph riders were towed to about 60 mph and
then pedalled up in the draft.
Jobst has never explained _why_ someone pedalling 130~180 RPM at the
record speeds of 125~165 mph can't be putting power into the rear
tire, particularly as he accelerates up from about half that speed and
cadence. What prevents the chain and sprockets from transmitting
power?
Simple calculations show that reasonable rolling resistance for the
tires, weight, and surface at 150 mph is probably 350~550 watts, which
would be just about right for riders straining like hell in the
relatively still air behind the various shields.
Cheers,
Carl Fogel
carl...@comcast.net
Dear D,
We can believe:
A) Jobst's hair-dust-and-bicycles-are-the-same theory, which claims
that no chains are needed and that it's all a sham:
"Pedals and drive mechanism are a sham, adding nothing to the
propulsion of the bicycle. I'm looking for the day that someone does
this, possibly with the same bicycle, with no cranks."
http://groups.google.com/group/rec.bicycles.tech/msg/9e3d2a3143f15d06
B) Phil's claim that an ordinary truck on a highway produces enough
draft to pull _two_ riders on a hefty motorcycle against their rolling
resistance--plus the braking effect of a 250cc twin cylinder 4-stroke
engine spinning over 6,000 RPM with no gas!
C) The accounts of _repeated_ runs at 100 to 165 mph by Meiffret (127
mph), LeGrys (110 mph), Letourner (108 mph), Abbott (138 mph), Howard
(152 mph) and Rompelberg (1, who all pedaled like hell in the
turbulence behind the pace cars after releasing the tow at around 60
mph, putting enough power into the rear tire through impressive
gearing to overcome the rolling resistance.
If it were just a matter of sitting behind a fast car, then the record
would have been as fast as the cars available. Yet in 1988, Rompelberg
(a highly experienced world-record motorpace racer) couldn't go as
fast as Abbott went 15 years _earlier_ in 1973 on the same Salt Flats.
Incidentally, Kramer and Rude fell just short of 100 mph (96 and 95
mph) behind _motorcycles_ instead of cars:
http://www.fredrompelberg.com/en/html/algemeen/fredrompelberg/record.asp#a02P1Q1LKT1UV6572MX66
Cheers,
Carl Fogel
Frank Krygowski
> On Mon, 8 Feb 2010 13:55:15 -0800 (PST), Frank Krygowski wrote:
>
> ...
> >Then someone put a fence or lip on the top rear edge, and that fixed
> >the stability. Supposedly, there was now one large, stable vortex. A
> >bit more drag than without the lip, but so much more stability that it
> >was worth it.
>
> >Now look at Howard's rig. That vortex would likely be a cylinder of
> >air rotating on a horizontal axis, going counterclockwise in that
> >view, passing over his head on the way back, then returning behind
> >him. The effect would be a push on the butt. And if the faster the
> >car goes, the harder that push.
>
> >At low speeds, the effect is enough to blow a convertible rider's hair
> >forward, or to blow road dust onto the rear window of a flat-backed
> >car. That means these vortices have a forward component greater than
> >the speed of the vehicle. At over 100 mph ground speed, the push
> Dear Frank,
>
> The breeze that will blow your hair or dust particles forward will not
> even begin to push a 220+ lb bicycle and rider forward against the
> rolling resistance of the tires at the same speeds.
It's not the same breeze, Carl. At 100 mph it's much more than a
breeze.
Does it not make sense that the forward velocity of at least some of
the trailing air is greater than the forward velocity of the vehicle?
If it were not true, we wouldn't need rear wipers on hatchbacks. Come
to think of it, if it were not true, I wouldn't get fumes in my car
(and have to lower windows and put the vent blower on high) when I
carry lumber sticking out the back of my hatchback.
> You want to sit in the back of a pickup truck doing 100 mph sometime.
> The turbulence, which is rather random...
A major point of my post was that the vehicle body can be shaped so
turbulence is controlled. I believe someone working on Howard's
project was smart enough to do that. People that build streamliners
tend to know a bit about aerodynamics.
> ... is not going to push a bicycle
> and rider up to 100 mph.
Which is why John Howard didn't draft a stock pickup truck. See how
it all ties together?
> Heck, according to the sillier theories floating around here, you
> could just toss a basketball out the back of a car at 100 mph and it
> would follow you for miles
Please. That tow vehicle is not just any car, w.r.t. aerodynamics.
> --the basketball has a far greater surface
> to mass ratio than a bicycle, yet somehow no one has filmed this
> happening.
I'm postulating a vortex rotating about a horizontal axis,
counterclockwise as viewed from the vehicle's right, with the axis
being perhaps above the height of the handlebars. The forward
component of velocity would be greater near the center of the vortex,
where Howard is. A basketball near the ground would feel less forward
velocity - and would be unlikely to find itself behind a custom-
modified, specially designed streamliner anyway.
> Simple calculations show that reasonable rolling resistance for the
> tires, weight, and surface at 150 mph is probably 350~550 watts, which
> would be just about right for riders straining like hell in the
> relatively still air behind the various shields.
Whether it's "still air" is the issue, isn't it? Remember,
observation shows there's a forward velocity component greater than
the tow vehicle's speed.
Work out the power input by a 150+ mph tailwind.
- Frank Krygowski
Hugh Fenton
snip
Not being a roller user, could someone explain to me why I've never heard of
anyone going anything like these speeds on a set of rollers? If there IS no
significant backdraft, I guess the bearing drag of 4 bearings, plus the air
resistance of the spinning rollers minus the advantage of a perfectly smooth
roller surface must account for a 2.5x difference in the drafting/roller
speeds quoted in this thread?
Hugh Fenton
Hugh Fenton
snip
Hugh Fenton
snip
Ben C
If you had John Howard's gearing it wouldn't be too hard to "exceed
152.2mph" on rollers. People do do roller competitions but they aren't
allowed gears higher than something fairly standard (53x12 or so) and so
it's really a test of how high a cadence you can spin your legs up to.
It's not really comparable to land-speed record attempts.
Jobst Brandt
> If you had John Howard's gearing it wouldn't be too hard to "exceed
> 152.2mph" on rollers. People do do roller competitions but they
> aren't allowed gears higher than something fairly standard (53x12 or
> so) and so it's really a test of how high a cadence you can spin
> your legs up to. It's not really comparable to land-speed record
> attempts.
With a 16:1 or greater chain ratio, you could not turn the rollers at
any speed. Tire rolling resistance (especially on rollers where it is
greater than on a flat hard surface) is greater than you can put out
and as I mentioned, Howard's bicycle was geared too high to be ridden
at any speed on a smooth flat surface.
Jobst Brandt
thirty-six
> Jobst has never explained _why_ someone pedalling 130~180 RPM at the
> record speeds of 125~165 mph can't be putting power into the rear
> tire, particularly as he accelerates up from about half that speed and
> cadence. What prevents the chain and sprockets from transmitting
> power?
On behalf of Jobst, the chain transmits force by compression. On
behalf of dimmy, a chain would be useless at such a speed, it would
just fall apart. ;-)
thirty-six
Dont make it complicated. Panel van without rear doors. Open
windows. There is a severe draught from the back to the front because
the air pushed out by the windsreen pulls the air from the cab as it
rushes by the window. I have been towed by such a vehicle (5yd tow
rope) at 30mph and decided to engage the gears despite knackered
bearings because I was on the brakes too much.
thirty-six
>
> > Cheers,
>
> > Carl Fogel
>
> Not being a roller user, could someone explain to me why I've never heard of
> anyone going anything like these speeds on a set of rollers? If there IS no
> significant backdraft, I guess the bearing drag of 4 bearings, plus the air
> resistance of the spinning rollers minus the advantage of a perfectly smooth
> roller surface must account for a 2.5x difference in the drafting/roller
> speeds quoted in this thread?
> Hugh Fenton
It wrecks the tyres and the slightest imbalance of a wheel has the
rider bouncing around at much lesser speeds. The drag is mostly in
the tyres, which is why they overheat and strip. Roller competitions
have their gears and cranks limited. Top riders turn pedal cranks at
over 250rpm.
carl...@comcast.net
Dear Hugh,
The USCF limits gearing in their roller races quite strictly:
"In roller races, either road or track bicycles may be used. All
classes are restricted to a development of 7.69 meters (25 feet 3
inches), and cranks must be at least 165 millimeters long." --from
2006 USCF rule book
Page down for the table of allowable gearing:
http://www.bikecult.com/works/rollers06INFO.html
For comparison, an ordinary 53x11 with a 700c x 25 and 175 mm cranks
develops about 10.2 meters--about 33% higher gearing.
Most roller racers are interested in fantastic sprinting from a dead
stop:
http://www.recordholders.org/en/records/roller1.html
Here are some of the details from that page and its links:
max
meters seconds avgmph maxmph gearing RPM
500 14.36 78 83 54x12 223
1000 32.48 69 74 54x12 208
102 54x11 262 (illegal 10.2 meter)
As you can see, the roller racer is running out of RPM because of his
gearing and doing a 30-second sprint.
The land speed riders are pedalling at 130~180, depending on speed and
gearing after run-ups that take several times as long as the
roller-race's entire duration.
Because of their standing-start emphasis, the roller racers just
aren't interested in 130x13 gearing or double-reduction 20-to-1, which
are made practical by towing land-speed bikes up to around 60 mph
before casting off the tow and pedalling up to 95 to 162 mph behind
the pace vehicle, either a motorcycle or a car.
It might be possible to build a motorized roller that spins up to 60
mph and to attach a double-reduction or giant front sprocket to
provide the gearing for 140~160 mph roller speeds, but it would be
rather expensive and unlikely to command much interest in the roller
world.
Keep in mind that most bicyclist enthusiasts can't even name any of
the land-speed record holders--land speed records are even more
obscure than the hour record, which is much cheaper, safer, and more
promising in terms of potential payback.
Land speed records are expensive, they're dangerous, and they're
financial sinkholes.
The bike, team, pace car, fuel, travel, and so on are astonishingly
expensive. Back in the 1980s, Howard needed over $80,000 in
sponsorship from Campagnolo and Hooker just to end up down in Mexico
(the Salt Flats stayed flooded) with a failed attempt on the record.
Cheers,
Carl Fogel
carl...@comcast.net
Dear Jobst,
So now you're claiming that it's geared too high to be ridden at _any_
speed on a smooth flat surface?
Please, tell us how the tire knows not to put any power into the
ground when an Olympic rider like Howard pushes the pedals.
You are aware, aren't you, that Whittingham turns some awfully high
gearing on a 5-mile run-up and a terminal speed of over 80 mph in a
60+ pound faired recumbent and no drafting?
Or is the Varna Diablo also a sham, according to you?
Cheers,
Carl Fogel
carl...@comcast.net
Dear Frank,
I worked out the rolling resistance elsewhere in this thread.
But let's start from the beginning.
The bike is going 60 mph when the tow is cast off.
What pulls it up to 150 mph? What kind of "tailwind" do you think is
needed to start pushing a coasting bicycle forward rapidly enough to
accelerate to 150 mph in the short time before it hits the speed trap?
How is it that the draft is always just right to keep the bike in
place, but not strong enough to mash it up against the bar? Darned
intelligent draft!
Remember, Jobst keeps insisting that no chain is needed and that it's
all a sham.
In fact, he's now writing that it's impossible to ride the bikes at
_any_ speed on a smooth flat surface:
" . . . as I mentioned, Howard's bicycle was geared too high to be
ridden at any speed on a smooth flat surface."
I wonder what gearing Jobst considers the limit?
Cheers,
Carl Fogel
Ben C
> Ben C? wrote:
>
>> If you had John Howard's gearing it wouldn't be too hard to "exceed
>> 152.2mph" on rollers. People do do roller competitions but they
>> aren't allowed gears higher than something fairly standard (53x12 or
>> so) and so it's really a test of how high a cadence you can spin
>> your legs up to. It's not really comparable to land-speed record
>> attempts.
>
> With a 16:1 or greater chain ratio, you could not turn the rollers at
> any speed. Tire rolling resistance (especially on rollers where it is
> greater than on a flat hard surface) is greater than you can put out
Where do you get this strange idea? We're talking here about static
resistance-- the minimum force required to get moving. That's extremely
low for a bicycle, whether on rollers or not.
But you can easily do an experiment. A regular bicycle has a gear ratio
of about 4:1, and a regular rider a weight of about 80kg. So if you put
your bike on rollers, put one of pedals at 3 o'clock and then place a
20kg weight on the pedal, according to you, it will not turn. I find
this very hard to believe.
> and as I mentioned, Howard's bicycle was geared too high to be ridden
> at any speed on a smooth flat surface.
Why not? Even if, for the sake of argument only, we accept your
assertion that he couldn't overcome static rolling resistance using the
pedals, he could just push himself off against the ground with his foot
and then start pedalling from there. Then all he has to do is move his
legs slowly.
thirty-six
> On 2010-02-09, Jobst Brandt <jbra...@sonic.net> wrote:
>
> > Ben C? wrote:
>
> >> If you had John Howard's gearing it wouldn't be too hard to "exceed
> >> 152.2mph" on rollers. People do do roller competitions but they
> >> aren't allowed gears higher than something fairly standard (53x12 or
> >> so) and so it's really a test of how high a cadence you can spin
> >> your legs up to. It's not really comparable to land-speed record
> >> attempts.
>
> > With a 16:1 or greater chain ratio, you could not turn the rollers at
> > any speed. Tire rolling resistance (especially on rollers where it is
> > greater than on a flat hard surface) is greater than you can put out
>
> Where do you get this strange idea? We're talking here about static
> resistance-- the minimum force required to get moving. That's extremely
> low for a bicycle, whether on rollers or not.
>
> But you can easily do an experiment. A regular bicycle has a gear ratio
> of about 4:1, and a regular rider a weight of about 80kg. So if you put
> your bike on rollers, put one of pedals at 3 o'clock and then place a
> 20kg weight on the pedal, according to you, it will not turn. I find
> this very hard to believe.
That's because you dont understand JB technology. ;-)
thirty-six
That'll be the bubbles, pulling him down ;-)
thirty-six
Van de Wall's Sausages?
dusto...@mac.com
Didn't see any open windows on Howard's or Rompelberg's tow vehicles.
Just sayin', 36.
Nor were the tow vehicles configured anything like a van, with a blunt
front end, long "square" body.
Apples-apples, oranges-oranges, anyone?
Was either of these vehicles taken to a wind tunnel? IRT "knowing a
bit" about vehicle dynamics, we've seen that something seemingly as
simple (and slow!) as a bicyclist being "optimized" for TT work can be
the source of surprises in a wind tunnel. "Obvious" doesn't always
work best.
Guessing, they adapted race cars via "cut and try" in the field.
--D-y
thirty-six
I doubt if you could get a rental van with a big enough engine and
gearing for the speeds required.
Ben C
Another way to quantify this static rolling resistance is to think of
how steep a hill you need before a stationary bicycle will start to roll
down it.
With a 16:1 chain ratio, I have an overall gain of about 30:1. This
means if I weigh 800N and put all my weight on the pedal, I have 26.67N
at the wheel.
I make that the same force pushing the bicycle forwards as I'd get if I
just sat on the bike on a 1.7 degree slope. I'm assuming the bicycle
weighs 100N.
So your claim is equivalent to the claim that if I sit on a stationary
bike on a 1.7 degree slope, without the brakes on, that I will not start
to roll down because of the rolling resistance of the tyres.
A 1.7 degree slope is a 3cm rise every metre. I think I'd be quite
worried if I didn't roll down that.
dusto...@mac.com
(me):
> > Didn't see any open windows on Howard's or Rompelberg's tow vehicles.
> > Just sayin', 36.
>
> > Nor were the tow vehicles configured anything like a van, with a blunt
> > front end, long "square" body.
(36 replied):
> I doubt if you could get a rental van with a big enough engine and
> gearing for the speeds required.
Yeah, I have my doubts as to highly refined the aerodynamics were on
either of these cars, or any dragster/Bonneville car of the 80's or
even the 90's-- again, "how much wind tunnel time?". But, certainly
better than a van with the windows open and no rear doors. Yeah,
getting one of those to 172+ would require huge amounts of energy--
which would likely be reflected in the amount of "backdraft". Hence,
apples-oranges, please, as we're talking completely different configs
here.
I never drafted behind a van with windows open and rear doors missing,
but in drafting at various speeds from about 18mph (combine in road
gear, other farm equipment) to "well over 40mph" behind dump trucks,
city busses, Winnebagos, etc., I've never felt a "push forward" where
I had to hit the brakes in order not to run into the MV I was
drafting. Quite the contrary-- the best drafts I can remember (don't
do that kind of thing much anymore <g>) was sitting close as possible
to the diff on dump trucks. Which was also a good thing because the
rocks coming up from the road and possibly spillage tend to have a
more rearward trajectory. But, stop pedaling and back you go.
Not doubting your story, just saying it's an unusual case at least in
my experience.
--D-y
thirty-six
Dont you know, " held up by a downward pull"? ;-)
thirty-six
thirty-six
The draughting behind a van was in a car. The car needed towing due
to faied engine bearings. The car may as well been driven, slowly.
Buses are not usually too good because of the usually large radius at
their corners, but sometimes work quite well at 30mph, it's worthwhile
trying both sides. There is an incline locally which although only
short, I do try to tail a bus. The tighter the radius of the
coachwork, the easier it is.
Jobst Brandt
>>> If you had John Howard's gearing it wouldn't be too hard to
>>> "exceed 152.2mph" on rollers. People do do roller competitions
>>> but they aren't allowed gears higher than something fairly
>>> standard (53x12 or so) and so it's really a test of how high a
>>> cadence you can spin your legs up to. It's not really comparable
>>> to land-speed record attempts.
>> With a 16:1 or greater chain ratio, you could not turn the rollers
>> at any speed. Tire rolling resistance (especially on rollers where
>> it is greater than on a flat hard surface) is greater than you can
>> put out and as I mentioned, Howard's bicycle was geared too high to
>> be ridden at any speed on a smooth flat surface.
> So now you're claiming that it's geared too high to be ridden at
> _any_ speed on a smooth flat surface?
That's what I said at the outset, and that is dependent on rolling
resistance of the tires and instability at essentially zero speed.
> Please, tell us how the tire knows not to put any power into the
> ground when an Olympic rider like Howard pushes the pedals.
> You are aware, aren't you, that Whittingham turns some awfully high
> gearing on a 5-mile run-up and a terminal speed of over 80 mph in a
> 60+ pound faired recumbent and no drafting?
> Or is the Varna Diablo also a sham, according to you?
I am not aware of Varna Diablo or the performance.
Jobst Brandt
thirty-six
> Carl Fogel wrote:
> > So now you're claiming that it's geared too high to be ridden at
> > _any_ speed on a smooth flat surface?
>
> That's what I said at the outset, and that is dependent on rolling
> resistance of the tires and instability at essentially zero speed.
LOL. Never heard of a push off?
Stop digging.
Michael Press
"Hugh Fenton" <hcfe...@hotmail.com> wrote:
The air resistance of the wheel in the air soon dwarfs all other power losses.
--
Michael Press
Frank Krygowski
>
>
> I worked out the rolling resistance elsewhere in this thread.
From what I can see, you worked out power requirements to overcome
different hypothetical values of rolling resistance. You did not work
out what the coefficient of rolling resistance really was for Howard's
tires on the salt surface. If you've got that Crr value, please post
it.
But here's how I'm looking at it:
If he and his bike weigh, as you claim, about 225 pounds, how much
rolling resistance drag would there be? Decent tires on smooth steel
drums at his 70 psi give a Crr of about 0.008. But Howard's on rough
salt. Would the Crr be double, perhaps? I don't know. But if it
were, his rolling resistance in pounds would be 0.016 * 225 lb or 3.6
pounds.
Now, how much thrust can he get at the ground when he pedals? The
gearing is 17.5 to 1. I'm guessing 170mm cranks, and it looks like
about 20" tires - say 250mm radius, for round numbers.
Then if Howard puts 180 pounds on the forward horizontal crank
(roughly, his entire weight), he gets a forward trust of
180 lb * 170 mm /(17.5 * 250mm) = 7 pounds.
So putting all his weight on the forward crank when it's horizontal
would, indeed, move the bike forward. But when the crank got down to
60 degrees (as opposed to horizontal) all his weight would not move
the bike forward. So he can move the bike only though a few degrees
of crank rotation.
Now maybe I'm estimating too high of a Crr for 70 psi 20" tires on
salt. But I don't see a way for these numbers to work. No rider can
put out torque equal to all his weight on a horizontal crank for any
practical amount of time.
> The bike is going 60 mph when the tow is cast off.
>
> What pulls it up to 150 mph? What kind of "tailwind" do you think is
> needed to start pushing a coasting bicycle forward rapidly enough to
> accelerate to 150 mph in the short time before it hits the speed trap?
You haven't commented on whether you believe the obvious fact that
there is a forward draft whose speed exceeds that of the tow vehicle;
but I hope that's so obvious it's beyond dispute.
So let's do a rough calculation of the relative wind speed needed to
produce some thrust. Say he wants a wind thrust that's triple his
rolling resistance. I guesstimated 3.6 pounds RR, so triple that
would be 10.8 pounds, or about 50 Newtons. Solving the equation for
drag force, F = 0.5 * Cd * A * rho * V^2 for V, using Cd = 1, A = 0.7
m^2 and rho = 1.15 kg/m^3 I get a relative wind velocity of just over
11 m/s, or 25 mph.
If that vortex curling over the top lip on the tow car, then whipping
down and forward, hits Howard's butt at a relative 25 mph, it triples
the power output needed to overcome rolling resistance. At least,
that's what I get.
> How is it that the draft is always just right to keep the bike in
> place, but not strong enough to mash it up against the bar? Darned
> intelligent draft!
Maybe _that's_ the real reason for fixed gears on these bikes - so the
rider can fine-tune his position relative to the car, backing off to
get just enough but not too much push from the air.
> Remember, Jobst keeps insisting that no chain is needed and that it's
> all a sham.
Perhaps if there were no chain (or if the bike had a freewheel) it
would need big, big brakes. But if that's the case and that's how it
were done, these riders wouldn't enjoy nearly so much hero status,
would they?
We can turn the calculation around, of course. If my guess of 3.6
pounds rolling resistance is decent, then to overcome just that (i.e.
no air resistance) at 150 mph requires nearly 1.5 HP, or over 1000W.
According to _Bicycling Science_ by Wilson, the absolute best human
beings using the absolute best mechanism might be able to put that
power out for roughly one minute. That's assuming, of course, that
they started well-rested, not that they did it as a finishing sprint
after a strenuous run-up to speed.
I know Howard was a fast guy, but do you really think he meets that
criterion?
> In fact, he's now writing that it's impossible to ride the bikes at
> _any_ speed on a smooth flat surface...
How far do you think you could ride a bike if you could barely
overcome its rolling resistance at the moment you had all your weight
on the forward horizontal crank?
- Frank Krygowski
Frank Krygowski
> On 2010-02-09, Jobst Brandt <jbra...@sonic.net> wrote:
>
> > any speed. Tire rolling resistance (especially on rollers where it is
> > greater than on a flat hard surface) is greater than you can put out
>
> Where do you get this strange idea? We're talking here about static
> resistance-- the minimum force required to get moving. That's extremely
> low for a bicycle, whether on rollers or not.
I used to ride rollers. (Not any more - too much work and too
boring.) But it takes a surprising amount of push on the pedals to
get the things going. I assume that's because the roller, being 6" or
less in diameter, pushes so far into the tire. There's a lot of
resistance there.
In fact, when one first tries riding the rollers, the trick is to get
up to speed without toppling. Invariably a novice will not push
nearly hard enough, the bike will immediately "slow" to near zero, and
the rider will topple or grab the nearby wall. I've known only one
exception, a very light, strong and agile 13-year-old who did it right
at his first try.
> But you can easily do an experiment. A regular bicycle has a gear ratio
> of about 4:1, and a regular rider a weight of about 80kg. So if you put
> your bike on rollers, put one of pedals at 3 o'clock and then place a
> 20kg weight on the pedal, according to you, it will not turn. I find
> this very hard to believe.
Keep in mind that to pedal a bike, you need to apply a certain minimum
_average_ torque throughout the entire 360 degrees. Having enough
torque only when the cranks are perfectly horizontal doesn't cut it.
- Frank Krygowski
Ben C
It depends on the resistance and your speed. There are two possible
problems: you slow down so much during the "dead spot" that you lose
balance, and you slow down so much that you actually stop and have to
overcome static rolling resistance again.
It's hard to imagine either happening in any reasonable road conditions
even with a 16:1 gear ratio, but I shall have a closer look at the
numbers in your other post.
With a very high gear you will have put a good deal of energy into the
rollers on the way down from perfectly horizontal, so it seems unlikely
that everything would stall when the pedal gets to the bottom.
But I gather balancing on rollers can be tricky at the best of times, so
riding a 16:1 on them might be easier said than done.
Ben C
But the bike will still move forwards even when the crank gets to 60
degrees. Using your RR value, between 60 degrees and the point where the
other crank is at 30 degrees, the bike will decelerate because RR will
be greater than thrust.
The question is how much. Between 90 and 60 is 30 degrees. We should
have another 30 degrees of positive thrust from that crank above
horizontal, and we can double it because there are two cranks. So 120
degrees out of 360 of positive thrust.
So we'll have a positive force over a third of the stroke that peaks at
about 3.4lbf, but a negative force over two-thirds of it that peaks at
about 3.6lbf using your figures for RR. In that case he is going to bog
down and be unable to get going.
> Now maybe I'm estimating too high of a Crr for 70 psi 20" tires on
> salt. But I don't see a way for these numbers to work. No rider can
> put out torque equal to all his weight on a horizontal crank for any
> practical amount of time.
It could work if Crr was a bit less. So long as he can more energy in
per revolution than he loses, he should quickly get up to the speed at
which he's limited by power output, just as in normal cycling.
But that may just be because your estimate of Crr is too high.
Difficult to estimate Crr, but if my numbers were right in my other
post, then we're saying that Howard's bike with him on it wouldn't roll
down a 1.7 degree slope on salt because of RR.
That still seems unlikely from where I'm sitting (which is admittedly
not on a bike on a 1.7 degree slope covered in salt).
carl...@comcast.net
Dear Jobst,
Er, you were just made aware of the Varna Diablo.
Willful ignorance isn't very convincing.
But to repeat what you've been told in these threads, the Varna Diablo
has averaged over 80 mph through the 200 meter speed trap at the
yearly Battle Mountain speed week. No tow, no draft.
The Varna team has been doing that for ten years and has been
repeatedly mentioned on RBT--and you're unaware of it?
Sam Whittingham pedals off with two people trotting next to him and a
fall-away training-wheel stabilizer. With a 5-mile run-up on flat,
level ground, he hits over 80 mph on his best runs, reaching 82.8 mph.
A current thread, of which you seem to be ignorant, mentions a woman
putting the Varna through the speed trap at over 75 mph--no tow, no
draft.
Whittingham also used the Varna to set an hour record in the open of
53.918 miles--no tow, no drafting.
The Varna's five-speed double-reduction gearing tops out at anywhere
from 220 to 293 gear inches, depending on whether Whittingham is
aiming at top speed or hour records, with a high gear of 75x12
connecting to a 34x16 and a 22" tall rear tire.
Whittingham pedalled the 220 gear-inch top-gear version at about 55
mph for an hour at 85~90 RPM against the wind drag with no draft and
against the tire drag.
In the sprint through the 200 meter speed trap, Whittingham pedals up
through five gears (four in earlier models) and is hitting 95~108 RPM,
depending on his 252~293 gear inch choices over the years.
No draft, no tow, ~100 RPM, over 80 mph. Plenty of videos, plenty of
forums discussing the details.
He can pedal 293 gear inches unassisted against wind drag at over 80
mph at ~100 RPM.
Now that you know what's going on, want to re-think your claims?
Cheers,
Carl Fogel
carl...@comcast.net
Dear Frank,
You might start by learning that salt raises rolling resistance less
than 20% over pavement.
Cheers,
Carl Fogel
carl...@comcast.net
Dear D,
This car, with a driver and passenger operating the throttle, was good
for 138.7 mph:
http://tinyurl.com/yh7zszw
As the two photos show, Abbott's 1973 pace car and shield were not
exactly wind-tunnel material:
"Our pace car was a modified stock drag racer, a 1955 Chevrolet with
what was later described as a 'toolshed strapped on behind.'"
--Racing the Wind, p. 111
Some of the gearing details in the article are typos or outright
mistakes.
It's not a 230 tooth--that would be a 130-inch circle, standing ~41
inches high.
You can see that Abbott's sprocket was only about knee-high.
In larger photos, the front sprocket looks like ~144 teeth, with 24
teeth per section and 6 sections, which would be a ~23 inch sprocket,
roughly what we see in the photos.
Abbott's gearing was significantly higher than Meiffret, who set the
previous record in 1962 with a 130 x 15.
Meiffret was pushed up to about 25 mph by a motorcyclist (not towed, a
later innovation) on the autobahn near Freiberg before he slipped in
behind the pace car for his 127 mph ride at ~180 RPM in 1962--with a
freewheel:
http://i50.tinypic.com/24x00w8.jpg
Again, not exactly a wind-tunnel pace car and shield.
The thing that looks like an upside-down periscope is actually a pipe
holding a wired microphone near Meiffret's face so that he can shout
at the driver to go faster. The front wheel hitting the roller (the
bump stick was also a later innovation) would prevent him from hitting
the microphone with his face, but it still looks like an insane idea.
In 1973, Abbott hit 130~140 RPM on ~60 psi 1.75" shaved-down Dunlop
motorcycle tires when he went through the mile speed trap at 138.7 mph
in 1973 at the Salt Flats. He helped Howard and Rompelberg in their
pursuit of higher speeds.
Cheers,
Carl Fogel
RobertH
What you say here actually supports Jobst's contention that one could
not get on Howard's bike and pedal off from zero mph. The rider would
need people to hold the bike up and give a push -- just like starting
the Diablo's record run.
Now I'm not convinced that someone couldn't get on that bike and roll
away unassisted, extremely slowly, if they had good low-speed skill.
Frank Krygowski
Got a source for that? Hopefully, one that's valid for tires that are
roughly 2" wide?
If so, you might also find the factor to correct from steel drum to
pavement. As we both know, the 0.008 I started with is a steel drum
value.
After you do those corrections, plug that new Crr into my equations
and tell me how much difference it makes.
- Frank Krygowski
z
Big difference here - the bikes of Rompelberg, Howard, et al. were fixed
or single speed. The Varna has at least five gears (and if I recall the
numbers on the windscreen, probably double that). The "handlers" are
there because whoever is driving the Varna has essentially no body
English to help balance the bike at startup speeds. Can you do a track
stand? Steering on the Varna must be extremely limited too. Visualize
trying to do a track stand in a fully faired bike like the Varna.
carl...@comcast.net
Dear Robert & Z,
Jobst's contention was that no one could pedal the bike usefully at
_any_ speed and that they had to be towed up to the record speed. No
one, according to Jobst in threads about land speed records, can
provide _any_ useful propulsion by pedalling above 60 mph.
Jobst is, of course, simply ignorant.
The Varna Diablo, which he claims to be unaware of, has repeatedly
broken 80 mph with no drafting advantage in a top gear ranging from
250 to 293 gear inches.
Everyone in the "recent" land speed records was pushed up to
reasonable pedalling speed by a motorcycle or towed up to speed by the
pace vehicle and was then freed at 25 to 60 mph to pedal on his own:
In 1962, Meiffret was pushed by a motorcycle up to 25 mph and then
switched over to draft a car to 127 mph on the autobahn near Freiberg.
After that, everyone towed.
In 1973, Abbott was towed up to 60 mph by a car on the Salt Flats
before casting off the tow and reaching 138 mph.
In 1985, Howard was towed up to about 60 mph by a car on the Salt
Flats before casting off the tow and reaching 152 mph. Previously,
he'd done the same thing on a paved highway in Mexico in 1983 without
reaching Abbott's 138 mph record--that's what you see in the YouTube
video, not the actual record two years later.
In 1995. Rompelberg was towed up to about 60 mph by a car on the Salt
Flats before casting off the tow and reaching 166 mph. Like Abbott and
Howard, Rompelberg made repeated runs over the years in various
places, working up to the current record.
The early Varna had 4 speeds, but soon switched to 5.
Cheers,
Carl Fogel
carl...@comcast.net
<hcfe...@hotmail.com> wrote:
>Hugh Fenton
Dear Hugh,
Aha, my aging memory finally coughed up what I couldn't find at first.
The record on rollers was set with a huge gear and a "tow" to 100 mph
in 1995. Bruce Bursford hit 208 mph on the rollers:
http://www.independent.co.uk/news/pounds-1m-bike-breaks-record-by-going-nowhere-1597625.html
http://autobus.cyclingnews.com/results/archives/august95/30_8.html
See the photos at the bottom here:
http://www.bikebrothers.co.uk/ultimatebike.htm
Cheers,
Carl Fogel
Frank Krygowski
>
>
> Jobst's contention was that no one could pedal the bike usefully at
> _any_ speed and that they had to be towed up to the record speed. No
> one, according to Jobst in threads about land speed records, can
> provide _any_ useful propulsion by pedalling above 60 mph.
Are you positive that's what Jobst meant? IOW, if he indeed said such
a thing, are you claiming he was including streamliners? Seems
unlikely.
Can you give a direct quote, with context?
- Frank Krygowski
Gennaro
On Feb 10, 8:43 pm, carlfo...@comcast.net wrote:
>>>> I worked out the rolling resistance elsewhere in this thread.
[...]
>>> But here's how I'm looking at it:
>>>
>>> If he and his bike weigh, as you claim, about 225 pounds, how much
>>> rolling resistance drag would there be? Decent tires on smooth steel
>>> drums at his 70 psi give a Crr of about 0.008. But Howard's on rough
>>> salt. Would the Crr be double, perhaps? I don't know. But if it
>>> were, his rolling resistance in pounds would be 0.016 * 225 lb or 3.6
>>> pounds.
>>>
>>> Now, how much thrust can he get at the ground when he pedals?
>>> (..)
>>> Then if Howard puts 180 pounds on the forward horizontal crank
>>> (roughly, his entire weight), he gets a forward trust of
>>> 180 lb * 170 mm /(17.5 * 250mm) = 7 pounds.
>>> (..) But when the crank got down to 60 degrees (as opposed to
>>> horizontal) all his weight would not move the bike forward.
>>> So he can move the bike only though a few degrees
>>> of crank rotation.
[...]
>>> You haven't commented on whether you believe the obvious fact that
>>> there is a forward draft whose speed exceeds that of the tow vehicle;
>>> but I hope that's so obvious it's beyond dispute.
[...]
>> You might start by learning that salt raises rolling resistance less
>> than 20% over pavement.
>
> Got a source for that? Hopefully, one that's valid for tires that are
> roughly 2" wide?
A couple of random remarks, based on what I read in this thread and
on the links to pictures some of you have posted (I have never
read anything else on motor-paced speed records)
http://i45.tinypic.com/m80ebn.jpg
(1a) Cyclists are obviously in a recirculation zone, and they are indeed
likely to be in a forward draft. I would be extremely surprised, though,
if anybody in this ng proved to be able to characterize the intensity
of this draft and its dependence from the speed of the car.
(1b) The cyclist is indeed supposed to be in the recirculation zone.
If not, the streamliner would have been made quite longer, well
extending over the head of the cyclists
(1c) Still, should actually the forward draft be strong and well-directed
enough, it is not clear why the riders are wearing tight clothing rather
than something designed to take aerodynamic advantage of the forward
draft (something large and flat over their backs, for example)
(2) As somebody mentioned, why are they making these attempts on
salt flats? At high speeds the tyres warm up significantly, and I
suspect that this fact has implications on the salt surface and on
its crr
(3) Even if cyclists were pushing only within +-30� of the forward
horizontal crank with each leg, they would be doing that from 2 to
3 times per second (per leg) when reaching maximum speed.
When the cyclist is pushing, he does that against rolling resistance;
when he's not pushing, rolling resistance is pulling backwards,
inertia of rotating masses, inertia of cyclists' thighs and (possibly)
forward draft are pushing forwards (let's not forget the cyclist
is already pedalling at a reasonably high cadence when the tow
is released).
Can you figure out a balance of all these forces? It's quite
difficult without mechanical and aerodynamical data, but I
bet the results will fit Wilson's power/endurance diagrams
for cycling champions :-)
> - Frank Krygowski
bye
Gennaro
Jobst Brandt
> Got a source for that? Hopefully, one that's valid for tires that
> are roughly 2" wide?
> If so, you might also find the factor to correct from steel drum to
> pavement. As we both know, the 0.008 I started with is a steel drum
> value.
> After you do those corrections, plug that new Crr into my equations
> and tell me how much difference it makes.
Most rollers, of which people speak, are not competition racing
rollers of old, that were wooden (light weight) and larger in diameter
than tubular racing tire/wheels. Most rollers today are made for
training purposes, are metal and significantly smaller than wheel
diameter, causing larger tire deflection under rider load than a flat
surface. Therefore, the RR of the two are not comparable.
Jobst Brandt
Frank Krygowski
other things:
>
>
> (3) Even if cyclists were pushing only within +-30° of the forward
> horizontal crank with each leg, they would be doing that from 2 to
> 3 times per second (per leg) when reaching maximum speed.
> When the cyclist is pushing, he does that against rolling resistance;
> when he's not pushing, rolling resistance is pulling backwards,
> inertia of rotating masses, inertia of cyclists' thighs and (possibly)
> forward draft are pushing forwards (let's not forget the cyclist
> is already pedalling at a reasonably high cadence when the tow
> is released).
> Can you figure out a balance of all these forces?
To put one item in perspective: the fact that positive torque comes
during only part of the pedal cycle is not unusual in the world of
machined. Obviously, something similar happens in power output from a
single cylinder engine. Something similar happens in power
consumption by a reciprocating machine (such as a stamping press). We
know how to handle the situation, given enough data. My point in
bringing the horizontal crank was simply to show that even in the most
favorable situation - full weight on a horizontal crank - Howard
probably barely overcame rolling resistance. It's obvious, I think,
that integrating his power output around a full crank revolution would
show he's not capable of powering the bike at any speed on his own.
> It's quite
> difficult without mechanical and aerodynamical data, but I
> bet the results will fit Wilson's power/endurance diagrams
> for cycling champions :-)
Another way to look at this problem is this way: Start with Wilson's
power vs. endurance graph. Look up the total time Howard was
supposedly powering his bike, read the graph to see how much power an
elite athlete could produce for that duration, and work backward to
find how low the rolling resistance would need to be to make the feat
possible with no aero push from behind.
Looks to me like the Crr would have to be negative.
(Remember the "flubber" from the movie, "The Absent Minded
Professor"? Tires made from that stuff might do the trick.)
- Frank Krygowski
z
I've not seen any rules regarding these type of attempts, but I imagine
there are some rules prohibiting overhead or side enclosures beyond a
certain point on the bike or rider.
>
> (1c) Still, should actually the forward draft be strong and well-directed
> enough, it is not clear why the riders are wearing tight clothing rather
> than something designed to take aerodynamic advantage of the forward
> draft (something large and flat over their backs, for example)
I would imagine that is more a function of safety, as the riders are
wearing protective motorcycle road racing leather suits for that reason.
>
> (2) As somebody mentioned, why are they making these attempts on
> salt flats? At high speeds the tyres warm up significantly, and I
> suspect that this fact has implications on the salt surface and on
> its crr
>
> (3) Even if cyclists were pushing only within +-30� of the forward
> horizontal crank with each leg, they would be doing that from 2 to
> 3 times per second (per leg) when reaching maximum speed.
> When the cyclist is pushing, he does that against rolling resistance;
> when he's not pushing, rolling resistance is pulling backwards,
> inertia of rotating masses, inertia of cyclists' thighs and (possibly)
> forward draft are pushing forwards (let's not forget the cyclist
> is already pedalling at a reasonably high cadence when the tow
> is released).
If the rider is reaching 150 mph @ 150 rpm, 60 rpm @ 60 mph is not high
cadence.
carl...@comcast.net
Dear Frank,
Jobst has repeatedly made the most amazing claims without evidence and
frequently in flat contradiction of the facts:
A) The bicycles cannot be pedalled at _any_ speed on a flat surface.
(Ridiculous.)
B) The bicycles are towed up to the record speed. (No, they're not.
All tows were cast off by 60 mph for 130+ mph records.)
C) No one can pedal a stationary bicycle even 50 mph. (Ridiculous.
Roller racers routinely exceed 60 mph with strictly limited gearing.
The roller record is 208 mph after a "tow" to 100 mph.)
***
Jobst _started_ the current thread with this claim:
"The bicycle [Howard] had a gear ratio so high it could not be pedaled
forward at any speed on a smooth flat surface. . . . The bicycle was
towed up to the maximum speed Howard's cadence could follow . . ."
http://groups.google.com/group/rec.bicycles.tech/msg/0fc415dca92f97d4
Just to clarify, Jobst immediately replied to his own post:
"As I said, the gear was so high it would not propel the bicycle in
still air at any speed."
http://groups.google.com/group/rec.bicycles.tech/msg/1b639dce4e8c1be0
And now he's explaining the details again:
With a 16:1 or greater chain ratio, you could not turn the rollers at
any speed. Tire rolling resistance (especially on rollers where it is
greater than on a flat hard surface) is greater than you can put out
and as I mentioned, Howard's bicycle was geared too high to be ridden
at any speed on a smooth flat surface."
http://groups.google.com/group/rec.bicycles.tech/msg/24044f3474f1e015
***
In the previous long thread about the same subject, Jobst announced:
"Like John Howard's bicycle, this one [Rompelberg] cannot be propelled
on flat ground by pedaling. Pedals and drive mechanism are a sham,
adding nothing to the propulsion of the bicycle. I'm looking for the
day that someone does this, possibly with the same bicycle, with no
cranks. Cranks that add nothing to propelling the bicycle."
http://groups.google.com/group/rec.bicycles.tech/msg/9e3d2a3143f15d06
"As I said, the gear is so high that the bicycle cannot be propelled
on level ground by a rider pedaling, mechanical losses exceeding the
riders power. . . . What else do you think is propelling the bicycle?
You cannot even pedal only the rear wheel of a stationary bicycle at
more than 50mph let alone a whole bicycle."
http://groups.google.com/group/rec.bicycles.tech/msg/f39ebfe7fc10d81b
"The bicycle had to be towed up to near the final top speed, there
being no way a rider could get over walking speed with all his power
to the pedals. At that high speed, the rider hasn't enough input to
turn the rear wheel that is not on the ground as the picture of Howard
shows in the "warm up" picture. Mile-a-minute Murphy knew that he
wasn't doing anything useful with his pedals and all the guys
thereafter knew it as well."
http://groups.google.com/group/rec.bicycles.tech/msg/56fa9a8f615024e7
"This is all meaningless because even on good rollers with narrow
large diameter drums, speeds of 60mph are not attainable."
http://groups.google.com/group/rec.bicycles.tech/msg/abaf41f6fc527936
"Towing bicycle and rider to speed before the measured speed trap is
also a must, no one having the power to accelerate bicycle and rider
on the course to that speed even in a theoretical vacuum available."
http://groups.google.com/group/rec.bicycles.tech/msg/ffbfb88212d345cb
"I claim that at high speeds there is a forward net force on the
rider, enough to propel th bicycle. This is obviously not true at 10,
40, or even 60 mph but it becomes effective at higher speeds. For
this reason and acceleration effort, the riders in these events are
towed to near the record speed they want to achieve."
http://groups.google.com/group/rec.bicycles.tech/msg/71effdc9bdfbb39b
***
carl...@comcast.net
>On 06 Feb 2010 23:57:23 GMT, Jobst Brandt <jbr...@sonic.net> wrote:
>
>>I take it the people commenting on his ride are newcomers to
>>wreck.bike. I saw the "bicycle" (two wheels) at InterBike when it was
>>news. The bicycle had a gear ratio so high it could not be pedaled
>>forward at any speed on a smooth flat surface. It had compound gear,
>>basically a 52-13 (4x) times 52-13 (4x), an 16:1 ratio.
>>
>>The bicycle was towed up to the maximum speed Howard's cadence could
>>follow and to make sure he didn't drift off into the wind eddies, his
>>bicycle had the engine throttle on the hand grip so he could maintain
>>minimum distance to the limit roller in the wind screen.
>>
>>To me the whole thing was an advertising sham, and many people
>>believed every bit of it.
>>
>> http://www.canosoarus.com/08LSRbicycle/LSR%20Bike01.htm
>>
>>This has all been discussed here on this newsgroup at length.
>>Where've you been?
>>
>>Jobst Brandt
>
>Dear Jobst,
>
>Er, where have you been?
>
>As has been previously and repeatedly explained to you . . .
>
>A) No, the land speed bikes are not impossible to pedal forward on
>flat surfaces:
> http://www.canosoarus.com/08LSRbicycle/LSR%20Bike02.htm
>
>That's a 138 mph land speed record bicycle being pedaled forward
>around a parking lot.
>
>B) No, Howard was not towed up to "the maximu speed" that hiss
>"cadencee could follow"--he was towed up to only 60 mph before he
>disengaged the tow cable and accelerated about 90 mph in the draft to
>152 mph.
>
>C) No, it wasn't a 52x13 double reduction. Howard used a 70x13 and
>52x16 double reduction, for a 17.5 overall sprocket ratio.
>
>Anyone who has "Racing the Wind" and "Pushing the Limits" can verify
>these previously points, which have appeared in threads that you
>stubbornly ignore.
>
>Cheers,
>
>Carl Fogel
Just a handy place to hang this.
The riders who didn't break land speed records are much harder to
find.
Here's the bike used an attempt that I'd never heard of:
http://i104.photobucket.com/albums/m170/aka_locojoe/bike%20boards/rrb/speed_bike2.jpg
It's the black double-reduction bike in front of Letourneur's
monster-sprocket 1941 record bike.
As the Bicycle Museum of America sign says, 135 mph in 1982. before
Howard.
Look closely--paired Rolf spokes, front and rear, and upside-down
motorcycle-style front suspension.
It was apparently developed at MIT and run at Bonneville, but was
about 3 mph short of Abbott's 1973 record 138 mph.
The rider was Aurelio "Ernie" Gallegos--you can see "EG" in the
reinforcing plate behind the steering tube.
Regrettably, the Bicycle Museum doesn't believe in direct links, but
if you go here, click on S, click on the right-arrow-button a few
times, and select "Speed Bike," you'll see some text to scroll up and
down and can go left and right through 6 small photos:
http://www.bicyclemuseum.com/alpha.htm
Alas, no details about pace car or towing. The astonishing 560"
rollout, higher than Howard or Rompelberg, is possible.
The solid front sprocket looks like a custom 60+ tooth, while the big
middle sprocket looks like a standard 52 or 53.
A 62x13 and a 53x12 will produce 560 inches on a 2124mm 700c--the
double reduction land speed bikes usually use gears of four different
sizes. (Howard used 70x13 and 52x16, and Rompelberg used 70x13 and
60x15, both with smaller diameter tires.)
Ernie switched to a more sensible bicycle in Vermont:
http://www.rutlandherald.com/apps/pbcs.dll/article?AID=/20070725/NEWS04/707250381/1002/NEWS01
Cheers,
Carl Fogel
z
I doubt those are paired spokes. More likely to be shadows from a camera
flash.
carl...@comcast.net
>carl...@comcast.net wrote:
>> Look closely--paired Rolf spokes, front and rear, and upside-down
>> motorcycle-style front suspension.
>
>I doubt those are paired spokes. More likely to be shadows from a camera
>flash.
Dear Z,
You may be right . . .
On the rear, the apparent pairing is much less convincing when I look
at it with your idea in mind.
But they still look like paired spokes when enlarged on the front:
http://i104.photobucket.com/albums/m170/aka_locojoe/bike%20boards/rrb/speed_bike2.jpg
No apparent shadows on the same background from the frame tubes.
Nor, at first glance, do any shadows appear on the same white
background behind the blue-rim Rolf with wider twin spokes right next
to the front wheel.
But maybe there are doubled shadows on the pegboard behind the blue
Rolf at about 11 o'clock? That would support the idea of impressive
shadowing.
If you're right, it's a 14-spoke front wheel (with suspension!) at 135
mph.
Cheers,
Carl Fogel
Frank Krygowski
>
> Dear Frank,
>
> Jobst has repeatedly made the most amazing claims without evidence and
> frequently in flat contradiction of the facts:
>
> A) The bicycles cannot be pedalled at _any_ speed on a flat surface.
> (Ridiculous.)
I don't think that's ridiculous, if by "pedal" you mean "maintain a
constant speed for five minutes using only the rider's power." You
really haven't addressed my calculations regarding full weight on the
forward pedal, vs. rolling resistance.
> B) The bicycles are towed up to the record speed. (No, they're not.
> All tows were cast off by 60 mph for 130+ mph records.)
I agree, the claims are that they towed only up to lower speeds...
perhaps, speeds at which aerodynamic push is large enough.
>
> C) No one can pedal a stationary bicycle even 50 mph. (Ridiculous.
> Roller racers routinely exceed 60 mph with strictly limited gearing.
> The roller record is 208 mph after a "tow" to 100 mph.)
And I agree, if the roller record is higher than 50 mph, Jobst must be
wrong.
>
> ***
>
> Jobst _started_ the current thread with this claim:
>
> "The bicycle [Howard] had a gear ratio so high it could not be pedaled
> forward at any speed on a smooth flat surface. . . . The bicycle was
> towed up to the maximum speed Howard's cadence could follow . . ."
> http://groups.google.com/group/rec.bicycles.tech/msg/0fc415dca92f97d4
Again, he may be wrong about it being towed up to maximum speed, while
still being right about the bike not being able to be pedaled
(unassisted) on a flat surface.
> Just to clarify, Jobst immediately replied to his own post:
>
> "As I said, the gear was so high it would not propel the bicycle in
> still air at any speed."
> http://groups.google.com/group/rec.bicycles.tech/msg/1b639dce4e8c1be0
I agree with Jobst. I'm open to being proved wrong, but you certainly
have not done so.
> And now he's explaining the details again:
>
> With a 16:1 or greater chain ratio, you could not turn the rollers at
> any speed. Tire rolling resistance (especially on rollers where it is
> greater than on a flat hard surface) is greater than you can put out
> and as I mentioned, Howard's bicycle was geared too high to be ridden
> at any speed on a smooth flat surface."
> http://groups.google.com/group/rec.bicycles.tech/msg/24044f3474f1e015
My numbers agree with those statements.
> In the previous long thread about the same subject, Jobst announced:
>
> "Like John Howard's bicycle, this one [Rompelberg] cannot be propelled
> on flat ground by pedaling. Pedals and drive mechanism are a sham,
> adding nothing to the propulsion of the bicycle.
My numbers agree. The pedals and drive mechanism may, however,
provide a way of fine-tuning position within the moving air at the
rear of the tow car.
> "As I said, the gear is so high that the bicycle cannot be propelled
> on level ground by a rider pedaling, mechanical losses exceeding the
> riders power. .
My numbers agree with Jobst.
> . . What else do you think is propelling the bicycle?
> You cannot even pedal only the rear wheel of a stationary bicycle at
> more than 50mph let alone a whole bicycle."
> http://groups.google.com/group/rec.bicycles.tech/msg/f39ebfe7fc10d81b
I disagree with the inability to spin a rear wheel at 50 mph, assuming
Jobst meant with the rear wheel suspended. I'm with you there, if I
understand him correctly.
> "The bicycle had to be towed up to near the final top speed, there
> being no way a rider could get over walking speed with all his power
> to the pedals. At that high speed, the rider hasn't enough input to
> turn the rear wheel that is not on the ground as the picture of Howard
> shows in the "warm up" picture. Mile-a-minute Murphy knew that he
> wasn't doing anything useful with his pedals and all the guys
> thereafter knew it as well."
> http://groups.google.com/group/rec.bicycles.tech/msg/56fa9a8f615024e7
It sounds like Jobst, at that point, wasn't considering any possible
aero push. I think it's more likely that the aero push (from the
bottom of the horizontal vortex) provided the power input.
But getting back to the main issue: Carl, how long did Howard ride
after casting off from the tow, to reach 152 mph?
How does his supposed power output jibe with Wilson's claims for human
power generation over time?
Seems to me that without some serious additional input power, his feat
would have been impossible - that no human could put out that power
for that amount of time.
Jobst claims the input power came from the car physically towing him
to top speed. I suspect it came from the car generating an
aerodynamic push from behind him.
So are you claiming that the power requirements are much less than we
do (super-small Crr), or are you claiming that the aging Howard was
literally off the charts (e.g. beyond Merckx) for power output?
- Frank Krygowski
RobertH
Clearly there is a need for a new record: Fastest flat land speed
obtained by a single bicyclist on a bicycle that they pedaled off
UNASSISTED from a stop.
Otherwise, it's not really bicycling imo.
dusto...@mac.com
Well, there's some sort (unofficial? official?) downhill (gravity
assisted <g>) record where the guy just hangs on and hopes for the
best.
I'm interested in any wrinkle. Just sayin'.
--D-y
thirty-six
Infinitely improbable?
Frank Krygowski
Hmm. I didn't think of the fact that he may have used an
improbability drive...
But then, where would he keep his towel inside that leather suit?
- Frank Krygowski