- 16 hours ago
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Motorcycles are just not good when it comes to aerodynamics. They punch a great big dirty hole in the air and do almost nothing to close it behind them. Kevin and Mark talk about moto aero, some historic solutions, and later in the podcast transition to MotoGP aero and related performance enhancing solutions. Tuck in and let's ride!
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Motorcycles are just not good when it comes to aerodynamics. They punch a great big dirty hole in the air and do almost nothing to close it behind them. Kevin and Mark talk about moto aero, some historic solutions, and later in the podcast transition to MotoGP aero and related performance enhancing solutions. Tuck in and let's ride!
Find us on Patreon! https://www.patreon.com/cw/CycleWorldPodcast
Become a Channel Partner: https://octanemedia.co/home/become-an-advertiser/
Listen on Spotify: https://open.spotify.com/show/6CLI74xvMBFLDOC1tQaCOQ
Read more from Cycle World: https://www.cycleworld.com/
Buy Cycle World Merch: https://teespring.com/stores/cycleworld
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SportsTranscript
00:00:00Hey, it's the Psycho World Podcast. I'm Mark Hoyer, Editor-in-Chief. I'm with Kevin Cameron, our technical editor. Thanks
00:00:06for joining us. Check out Patreon. We're on Patreon. The link is in the description. You can get additional content
00:00:14there.
00:00:15So we do extra podcasts during the week. We'll post one or more extras per week over on Patreon, and
00:00:22we'll be adding some other fun stuff in the background, and eventually we'll do some live stuff with the audience
00:00:29there for members. That's cool. So join us over there. You would also get all the podcasts we've done without
00:00:38commercial interruption, as we do here on the fabulous YouTube channel.
00:00:41So join us over there. This week's topic, I've wanted to call it the tragedy of motorcycle aerodynamics because they're
00:00:50just horrific. They are pretty terrible for aero. This is a two-part episode, Kevin. We'll talk about aerodynamics and
00:01:01drag and what we do with fairings and all of that. Plus, we'll get into MotoGP and what Kevin likes
00:01:08to say about horsepower wrecking motorcycles.
00:01:11So to speak, so to speak, the more problems. It's not wrecking them. It's just causing more problems. 275 MotoGP
00:01:18horsepowers or 300, or as we have now influenced the folks at S&S, they refer to the horsepowers as
00:01:26toasters now because you have analogized to the watts.
00:01:30It's so wonderful because a toaster is 750 watts and a horsepower is 746 watts. Close enough.
00:01:38Yeah.
00:01:39So when you say, oh, there's this many horsepower lost in the primary gear, you think about that in toasters.
00:01:46Just put your face right down over a toaster as your bread toast. It's impressive. Lots of energy.
00:01:52If you've never seen a toaster later, Kevin, or audience, look up the toaster later. Toaster later is a vertical
00:02:01toaster, has a slot on the side, and it has a mineral glass window so you can see the toast
00:02:10moving through.
00:02:11And it has this series of claws along the bottom, and you put your bread in, and it goes like
00:02:17this.
00:02:18Yeah, yeah. And the claws just move the bread across the toasting elements, and then it falls out toasted on
00:02:26the other side.
00:02:26And if you want it more toasty, you slow down those claws.
00:02:30Little claws.
00:02:30And you want your white toast, very light toast, make it through, move through quick. I have a toast later
00:02:36at home.
00:02:37It's a miracle of, well, it's a horsepower at least.
00:02:44Yep.
00:02:45So, toasters. Anyway, aerodynamics, Kevin.
00:02:50Okay. Well, the big problem, of course, is that our planet has an atmosphere.
00:03:00And if we had a way to operate motorcycles on the moon with something other than heavy batteries, mind you,
00:03:13$8,500 to low Earth orbit, higher prices may apply to lunar.
00:03:21The thing is that there would be no aero drag, and so you would simply have rolling resistance.
00:03:28And on the moon, that would be reduced by 80% because the moon is much lighter than the Earth,
00:03:34and therefore its gravitation is weaker.
00:03:39But we do have an atmosphere, which makes it possible to carry just fuel.
00:03:44A rocket has to carry fuel and oxidizer, but we get ours from the atmosphere.
00:03:49So, here we are plowing through the atmosphere on our motorcycle, and we're noticing that, oh, we're doing 225 miles
00:03:58an hour,
00:03:59and we're still accelerating, and the front end is awfully light, hit a good bump, and you kind of get
00:04:05an unpleasant feeling.
00:04:07Many riders have talked about this happening at COTA, where the subsoil is clay, and when water hits it, it
00:04:18swells crazily.
00:04:20So, the straightaway has these undulations in it, and when you go over the top of an undulation, tendency for
00:04:26the front wheel to come up.
00:04:28Well, no, no, no, don't do that.
00:04:30So, what's happening when drag is produced, we're getting an echo.
00:04:41Is that you're transferring energy from the moving vehicle to the atmosphere around it.
00:04:47And I had this graphically demonstrated to me, riding my 125 BSA Bantam, 4.95 horsepower at 4,500, drafting
00:05:04a box truck.
00:05:07As the truck forces its way through the air, the air is divided.
00:05:12Some flows over the top, some flows past the sides, and a confused mass tumbles underneath.
00:05:18But as the flow along the sides and top reaches the rear edge of the box, it encounters a low
00:05:27pressure because that area is surrounded by low pressure, namely moving air.
00:05:37When air moves, its pressure drops as its kinetic energy increases, and when it slows down, its kinetic energy is
00:05:46reconverted back into pressure.
00:05:48Well, that low pressure behind the truck causes those flows to immediately curl in behind the truck.
00:05:57And nothing is perfectly symmetrical in this world.
00:06:02So, one of the two vortices that's forming on the sides grows faster than the other, and poof, it pushes
00:06:11that one off, and it streams back and hits me.
00:06:15Biff.
00:06:16And then the same process repeats, right hand rather than left hand.
00:06:23Pow!
00:06:24Saco!
00:06:25And I went up the road, alternating right and left.
00:06:32Now, that whirling air, the velocity in that whirling air is the velocity basically coming along the sides of the
00:06:39truck.
00:06:40So, it is creating whirling masses of energetic air and just leaving them behind.
00:06:49And this is analogous to the tip vortex produced by a wing.
00:06:54The pressure on the lower side of the wing is higher than that on the upper.
00:06:59So, air tends to spill off the tip, flowing upward from underneath and curling around the lower pressure on top.
00:07:10And this streams back from the aircraft steadily.
00:07:14And woe betide the single-engine novice who, having looked at his or her watch and said, I'm clear, pushes
00:07:25the throttle forward, and moments later is completely discombobulated, upside down, right side up, etc., upset by hitting one of
00:07:35these powerful vortices.
00:07:37Well, that energy is taken from the vehicle as drags, okay, well, we have wingtip devices now, don't we?
00:07:47Oh, it's much better.
00:07:48But now think of this.
00:07:51The pressure on the underside of the wing being greater than that atop the wing, there tends to be a
00:07:57net flow on the underside, a component of flow, that is wingtipward.
00:08:02And there's an opposite direction on the upper surface.
00:08:07So, when those two flows, one over the top, one along the bottom, combine at the trailing edge, they form
00:08:14a whole sheet of vortices that are spinning.
00:08:19They all are energy-rich drag.
00:08:26So, when I went to the 93 Australian Grand Prix at Eastern Creek, there was a misty morning practice, and
00:08:35I could see that the wakes of the 500 bikes were just whirling masses of turbulence.
00:08:46Nothing like the beautiful, sinuous lines superimposed on an image of the new model in the brochure that show beautiful,
00:08:57graceful, persuasive streamlining.
00:09:01Oh, yeah.
00:09:03And we've all seen that.
00:09:04Oh, the Hayabusa press kit.
00:09:06Yeah, the Hayabusa press kit has these beautiful, like, blue lines, and it just looks like perfection.
00:09:12Yes, they're great.
00:09:13And knowing that it's not perfection.
00:09:16But then we put the motorcycle and rider into the tunnel, and we measure their drag, and we find that
00:09:23it is comparable with that of a sheet of plywood of frontal area equal to that of motorcycle and rider,
00:09:33pushing perpendicular to the airflow.
00:09:38In other words, pretty much as bad as it can get.
00:09:43It's bad.
00:09:44The plywood's better than a motorcycle.
00:09:46Yes.
00:09:47This thing, this tremendous drag, is given the arbitrary number of one.
00:09:56And if we have only half that much drag, which some motorcycles with fairings and so forth do, and maybe
00:10:03even down in the point fours, it's twice as good, or maybe a little bit better than that, twice as
00:10:12good as a sheet of plywood that is cramming through the air.
00:10:16Now, the aerodynamic coefficient does not tell you the drag, you have to multiply, you have to put that coefficient
00:10:27into an equation which will give you an idea of the drag.
00:10:31It's not a precise thing that you can calculate exactly, but it gives you an idea of what it's going
00:10:38to be.
00:10:39So, a 0.5 drag coefficient is comparable to that of a box truck, and that's where motorcycles are.
00:10:51The rider tucks in and adds a fairing, maybe 0.4 something, maybe 0.5, but about equivalent to the
00:11:02drag coefficient of a box truck.
00:11:06Pretty good.
00:11:07Now, this is why a MotoGP bike needs whatever that tremendous horsepower it is that it has to go 225
00:11:18miles an hour.
00:11:19And it's still accelerating when it gets to that speed.
00:11:25So, that is not its top speed at all.
00:11:28We don't know what its top speed is.
00:11:31But then again, we turn our minds to that lovely invitation to end your life early, as some saw it,
00:11:41the BD-5 home-built, with its 55-horsepower snowmobile engine.
00:11:502.8 square feet, something like that, of frontal area.
00:11:57200 miles per hour.
00:12:00With the pilot.
00:12:03And the drag coefficient improves enormously in a vertical dive because you don't have to generate lift.
00:12:09Lift always generates a component that is drag.
00:12:15So, that's the lift over drag coefficient that you've probably heard of.
00:12:19You want the lift to be generous, and you want the drag to be parsimonious.
00:12:26Well, it's the big compromise in aircraft.
00:12:29You know, you get these, what is it, the F-104 with his little stubby?
00:12:35Stubby little wings.
00:12:36Yep.
00:12:37Could go sure fast, but you have to land really fast.
00:12:39You can't get that 40-mile-an-hour touchdown.
00:12:42And when they put the flaps down, the air refused to follow.
00:12:45No, I'm going straight to hell with you.
00:12:49And so they had to blow the flaps.
00:12:51They had to push energetic air out there.
00:12:55To shoo away the turbulent boundary layer, wonderful phrase, turbulent boundary layer,
00:13:02makes us all seem so cerebral.
00:13:05Well, it's that P-51, that scoop on the bottom of the P-51 is not fared.
00:13:10It is not fared into the airframe fuselage.
00:13:13It has a gap because it can't use that air.
00:13:16It wants to be in the not that air.
00:13:17And all that the boundary layer is, is the molecules that have been slowed down
00:13:24by colliding with the surface of the vehicle.
00:13:28And they form a layer of relatively stagnant flow.
00:13:34You don't want that, trying to weakly push its way through the radiator core.
00:13:40I'd like to cool, but I'm just going to sit over here.
00:13:45Laguna Seca, 1988-1989, Grand Prix 500s, cresting turn one.
00:13:52We got up at 4 a.m. to get our spot on the fence because the hill had not been
00:13:58cut back yet.
00:13:59So it was kind of dangerous, but you were right on top of those guys going over one,
00:14:03which is that, you know, it's barely a corner at Laguna.
00:14:06And then the big corners turn two.
00:14:08But they would go over, particularly on the plug chop.
00:14:11But a two-stroke was so quiet on overrun that when they would, and then plug chops.
00:14:17So they crest the hill and everybody's doing a plug chop at the end of practice to check
00:14:21their mixture.
00:14:22And the bikes would go over and the fairings would go, they would be fluttering.
00:14:27And there was no other noise except aero.
00:14:30And then they'd go and they'd stop at the entrance of two.
00:14:32They just put the brakes on.
00:14:33And there goes Kel Carruthers walking down to pick up Eddie and pushing the bike.
00:14:39And then Kevin's walking back and his, Kevin Schwantz is walking back and his Pepsi Suzuki
00:14:44is being pushed by the mechanic and we're yelling.
00:14:46But you could hear the turbulent boundary layer on those little potato chip fairings going,
00:14:51it was, that was spectacular.
00:14:53What a memory to be there.
00:14:55Yes.
00:14:58So an airplane has a, closes its wake with a tail.
00:15:04And the tail, a streamlined body like a fish or a bird, is essentially a Venturi turned
00:15:15inside out.
00:15:16A Venturi is a duct which starts large, quickly tapers down to a small diameter, and then slowly
00:15:26expands back to the original diameter.
00:15:29And what happens is this produces a very low pressure at the point of highest velocity.
00:15:36As we observed before, if the air accelerates, it's gaining kinetic energy, which means it's
00:15:42taking away pressure energy.
00:15:45The molecules are going in this direction at a tremendous speed.
00:15:48And that speed is subtracted from their random beating on the walls of the duct.
00:15:58So this thing works well.
00:16:02The pressure in is very close to the pressure out because accelerating down to that small
00:16:10orifice is quite smooth.
00:16:13The difficult part is expanding the flow to slow it back down to its original velocity,
00:16:21turning the energy of velocity, kinetic energy, back into the energy of pressure.
00:16:28Now, what you're trying to do with a tapered tail is air has had to accelerate to make, to go
00:16:37out around the bow of whatever it is that's moving.
00:16:42It has accelerated.
00:16:44Now, what we would like to do is get that energy back, not let it become drag.
00:16:50We want to taper the back of the vehicle such that the airflow will adhere to it and apply pressure
00:16:59to it
00:16:59as it slows back down and finally leaves close to the tail.
00:17:08Well, it's interesting.
00:17:09The airframe evolution, if you look at your—I mean, look at any 60s aircraft,
00:17:15anything that was designed in that era from your Cessna 150s, your 421s, twins.
00:17:21And then you'd look at the Diamond Aviation.
00:17:24They have a DA42 twin star.
00:17:26It's called.
00:17:27It's a diesel piston engine twin.
00:17:30And if you look at the tail section of that and the difference between, you know,
00:17:35this kind of World War II fighter look where it's 30s and it just kind of straight lines back,
00:17:41the DA has a very—and most current design aircraft, like a Cirrus, it goes and it has quite a dramatic
00:17:49taper.
00:17:49And I'm imagining that's convert—that's, you know, making the pressure that you're talking about is why they're doing that.
00:17:55Yes. And on the tail of a fish, if you're trying to grasp a fish, a fish is slippery.
00:18:04So your dad puts his two fingers into the fish's gills and holds it up.
00:18:10Look what we did.
00:18:12We're great anglers.
00:18:14You don't take hold of the body of the fish because, floop, it's tapered.
00:18:19And the harder you squeeze, the faster it shoots out of there.
00:18:23What we want the tail for is for the air to squeeze, and some of that vector of squeezing points
00:18:33forward.
00:18:34You are recovering pressure so that it can push the aircraft forward.
00:18:39A motorcycle has no tail.
00:18:43And that's why—
00:18:44Except for Dennis Manning's land speed stuff.
00:18:47So I interviewed Dennis Manning like 20 years ago, and I asked him about, you know, I asked him about
00:18:52aero.
00:18:53And he's like, well, you know, salmon and other fish have been at it a really long time.
00:18:59So that's—he's like, that's where we—that's kind of where we start.
00:19:02And, you know, they have to—they have to be careful about the center of pressure, where the pressure is for
00:19:07stability.
00:19:08You know, there are—
00:19:09Yeah.
00:19:10There are things to think about at 200, 300, 400 miles an hour.
00:19:14So if the back end comes around, you want the natural aerodynamic forces to tend to push it back straight,
00:19:21not to make it worse.
00:19:25Now think about this.
00:19:27Sorry.
00:19:28One more related—
00:19:29Oh, okay.
00:19:30Yeah.
00:19:31One more related story.
00:19:32Terry Vance was—I interviewed Terry Vance of Vance and Hines.
00:19:36So he got a start in drag racing.
00:19:38He was, you know, he was with Rich Collins, RC Engineering, and they were doing Hondas, and then he and
00:19:44Byron Hines started Vance and Hines.
00:19:48And they made tons of money, and they made zillions of exhaust systems.
00:19:52And he was a successful drag racer, and he went to top fuel.
00:19:55And they just decided to go top fuel racing.
00:19:58They're like, yeah, let's make some body work.
00:19:59And so they made some body work, and it was like a fiberglass wedge thing that they were putting.
00:20:04And it had a little tiny nose and it had a big spoiler on the back, and they were running
00:20:07a huge tire.
00:20:08But they didn't do any aerodynamic work.
00:20:11And he said the body wasn't even symmetrical.
00:20:15It was just like, yeah, that looks pretty good.
00:20:17And the guy made the body, and it was sort of like maybe slightly crooked.
00:20:20And he said when he ran that thing down the strip—he's doing 200 miles an hour plus—he said it was
00:20:27like trying to fly a dart backwards.
00:20:29He said it was incredibly difficult to run.
00:20:32So that's my Terry Vance.
00:20:33That's right.
00:20:34Yeah, that's my Terry Vance aerodynamic story.
00:20:38Seen in gross terms, drag is the difference between the pressure on the front of the motorcycle and the pressure
00:20:48on the rear of the motorcycle.
00:20:50And if you don't have any tail, the pressure on the rear of the motorcycle is like the pressure behind
00:20:55a flat piece of plywood that is being crammed through the air by a motor.
00:21:02And that means that the drag will be very high.
00:21:05Anyway, when Craig Vedder, I think he did something impromptu with cardboard and duct tape once to show how easy
00:21:19it would be to increase the top speed of low-powered get-around-town motorbikes.
00:21:26And he started cutting out cardboard and made a tail, and he made a sort of rounded fairing for the
00:21:33front, and pretty soon he had the thing going pretty fast.
00:21:36And all he was doing was trying to increase the pressure on the back of the vehicle by designing a
00:21:45tail to which the flow would attach itself.
00:21:49And by attaching itself, exert pressure on it, just like trying to hold on to a slippery fish.
00:21:57There was the Craig Vedder fuel economy challenge that was part of that, and folks were just trying to hypermile,
00:22:04and they were building big little wing things that you would sit in, completely enclosed vehicles, and trying to continue
00:22:13the body work.
00:22:14You know, we're limited by the FIM rules.
00:22:16We don't get dustbin fairings that have the big nose that stick way out in front of the front wheel,
00:22:22and we can't extend them off the back.
00:22:25Yep.
00:22:25So we have an aero limitation by rules alone, but not on the street.
00:22:31If we want to get into our cigar, we can.
00:22:35We can live it up.
00:22:38So it turns out that one of the worst things that you can do is to have junk sticking out
00:22:45of your smooth aerodynamic shape.
00:22:48And the example that I like to give is the front wheel, the brake discs, the calipers.
00:22:56All of it.
00:22:57It's just sticking out there.
00:22:59Yes, the rider's elbows.
00:23:01You know, there are some riders who were called Mr. Elbows.
00:23:06Yeah, totally.
00:23:07All of it.
00:23:08And we have to bear in mind, of course, that the rider's manner of riding the motorcycle is very important.
00:23:15And if that's the way he or she feels most comfortable, that's fine.
00:23:20Well, Rich Oliver on his 250 at Daytona said he would come off the seat and arch his back until
00:23:30his leathers stopped having turbulence.
00:23:32Yeah, you could feel them detaching from your back.
00:23:35And he would.
00:23:36Low pressure.
00:23:37Yeah, he was trying to continue that arch from the fairing to those drooped tail sections that they were running
00:23:43on.
00:23:43It can still be seen in MotoGP, people putting their butts up on the seat back a bit.
00:23:48Because it looks smooth.
00:23:50You can draw this line, the windscreen, the rider's helmet, the back.
00:23:55Oh, it's going to be great.
00:23:56The original active aero.
00:23:58Yes, but the air looks at it.
00:24:01This stinks.
00:24:01I'm not sticking to that.
00:24:04Yeah.
00:24:04I'm out of here.
00:24:07So when excrescences, add that one to Asperides and Velocet, if you will.
00:24:15When excrescences jut from the smooth salmon-like contour of our creation, they are especially drag-producing because the awful
00:24:29turbulence that streams off of them flows down the surface of the vehicle and ruins the flow there as well.
00:24:37So here we are in our B-47 1950s jet bomber, the U.S. first swept-wing jet.
00:24:54And we have, we're preparing to land someplace, unknown AFB, and we extend the undercarriage, as the British say, gear
00:25:08down.
00:25:10And if we do this at, what is it, 225 knots, the maximum at which the gear is permitted to
00:25:18be extended, the drag of the airplane doubles.
00:25:24And on commercial airliners, it is said that extending the gear more than doubles the fuel consumption.
00:25:36So, just looking at the front of the motorcycle, of course, we've been seeing the same look since 1958, which
00:25:46was the first year of the FIM rule that said the front wheel must be completely exposed.
00:25:52There can be no streamlining ahead of a vertical plane through the front axle.
00:26:00At various times, they changed that, they made it 50 millimeters ahead, then 100, now they think they've come back
00:26:06to 50, I'm not sure about that.
00:26:10But there is this awful thing sticking out front.
00:26:15And I went to see some MIT aero guys.
00:26:22I wanted to put my home-built H2R into their low-speed tunnel, low-speed meaning 140 miles an hour,
00:26:30as it then was.
00:26:32And they were telling me that this was a bad idea.
00:26:34They said, there isn't even a dynamic model for motorcycles yet.
00:26:37What do you want to, eh, it's foolish.
00:26:40But they gave me an example.
00:26:42It's foolish.
00:26:44Can we just write that down under motorcycling, period?
00:26:49Like, that's why it's so great.
00:26:51Yep.
00:26:52Because with motorcycles, we're really on our own.
00:26:55So many of the improvements that have come to motorcycling have come from the users,
00:27:00and not from mighty electronic brains in the employ of the manufacturers.
00:27:08Not that they haven't made their contribution.
00:27:10But at any rate, this mass of stuff out front reminded these two MIT profs of something that happened during
00:27:25World War II.
00:27:34World War II aircraft with airborne radar did not have little dishes that panned and tilted underneath a fiberglass cover.
00:27:47They were dipole arrays that were just stuck out into the wind.
00:27:51And they found that if they put a flat surface behind these arrays, that the velocity of air passing through
00:28:03all those dipoles,
00:28:06you know the phrase, the wind in the wires, the World War I fighter plane movies where you hear the
00:28:14bracing wires of the wings singing as our hero dives to what could very well be his demise.
00:28:22Keep tuned in, folks, for the outcome.
00:28:24But off of each of those dipole arrays is streaming, vortex shedding.
00:28:34And the tone that you hear is the speed with which those little vortices are being produced.
00:28:41Anyway, if they put a flat plate behind that, the airflow tended to be pushed ahead by the flat plate,
00:28:49reducing the drag caused by the dipoles to buy a useful amount.
00:28:55And I showed them a picture of Kawasaki's, what year was it?
00:29:02There was a year that they had a chin projection that reminded me of Abyssinian, the beards of Abyssinian kings.
00:29:14And they said it could very well be that that flat radiator reduces somewhat the terrible drag of all that
00:29:22chunk sticking out in front.
00:29:24So, it is almost as though those rules makers at the end of 57 were trying to increase the drag
00:29:37of motorcycles.
00:29:38The front wheel must be exposed.
00:29:40There can be no streamlining behind XYZ and all of this business.
00:29:47And so, we just keep adding power.
00:29:54That's how you go faster.
00:30:00And it's strange.
00:30:02Another thing that used to bother me is people would put fairings on their motorcycle.
00:30:07And instead of shaping them so that the fairing ended quite close to your tucked in knees, the fairing was
00:30:19made like a plow, getting wider toward the back so that it was throwing air outward.
00:30:25And I'd say, is that, do you have a reason for wanting to do that?
00:30:31Yeah, I like the way it looks.
00:30:33Good.
00:30:35I'll remember that.
00:30:39So, such a good-looking bike in 13th place, didn't you think?
00:30:44Styling, man.
00:30:48So, the front of the fairing, in a lot of those late 60s bikes, was just a huge opening.
00:30:57So, all that the fairing was, was a hemisphere for the front number to be painted on with a large
00:31:06plastic windscreen that most riders made come to the top of their helmets.
00:31:15Honda created quite a stir by making it come to the top of the rider's shoulders.
00:31:22And the sides of the fairing had no streamlining purpose whatsoever.
00:31:27They were just like flat sheets that were connected by maybe a six-inch tongue on either side that joined
00:31:34this hemisphere.
00:31:36They weren't streamlined at all.
00:31:39They were covers.
00:31:40And that's what I called them.
00:31:42Covers.
00:31:44And you could put the numbers on the side.
00:31:46Well, you know, in recent conversations with Steve McLaughlin and John Ulrich, Steve was one of the instrumental guys in
00:31:56making his fairings larger so he could fit more sponsors on them.
00:32:00So, there you go.
00:32:03Good stuff.
00:32:04Good business.
00:32:05Might have helped there eventually.
00:32:071980, I helped a, one of the early super cart guys.
00:32:13Super cart meant that you had a six-speed, usually a Yamaha engine at that time, on the back of
00:32:19your cart.
00:32:21And he had an enormous World of Outlaws style wing that was tipped up at a jaunty angle.
00:32:32And I kept saying, John, you've got to take that thing off there.
00:32:38I've got to have it on there and sponsors.
00:32:40I've got to put all the sponsors on there.
00:32:42Could we just level it off so that we could reduce the drag somewhat?
00:32:49I kept after him.
00:32:50Eventually, he said, okay.
00:32:52Picked up like 30 miles an hour.
00:32:56Yeah.
00:32:56Because what he was doing was carrying that sheet of plywood that we were just discussing.
00:33:01Well, instead of having it absolutely flat, it was tipped back a little bit.
00:33:10And this was supposed to produce a downforce that could overcome the fantastic power of the 250 Yamaha.
00:33:1940 horsepower?
00:33:21Yeah.
00:33:26So, then along comes Harley-Davidson.
00:33:29They have their wonderful moment.
00:33:33A bunch of guys spending the afternoon at Axtell's shop playing with a Harley flathead.
00:33:43Dick O'Brien, the Harley racing manager, comes out because they found something.
00:33:48And in the course of trying to gain as much as they could from this, not only did they put
00:33:55on two Tillotson's instead of one, carburetors those were.
00:34:01They also went to the Caltech wind tunnel and a fairing was designed for this motorcycle, which has not, subsequent
00:34:10to that time, failed to increase the speed of every motorcycle it was ever put on.
00:34:18Because it had a limited opening for cooling.
00:34:21It wasn't just a hemisphere in the front and two plates on the side.
00:34:27And the widest part of the fairing was at the front and it tapered inward from that point as though
00:34:35it were trying to create a streamlined tail.
00:34:40And in effect, what it was doing was reducing its wake area.
00:34:47And this was not so much science at work as a combination of aerodynamic theory and hours spent in the
00:34:58tunnel.
00:35:00Well, yeah, I'd like another beer.
00:35:04That looked like it was going to work, but it didn't.
00:35:07So now we've got to think about it again.
00:35:12So Harley comes in 68.
00:35:16Triumph has won the Daytona 200 twice in a row and Harley's looking like a pretty tired 1930s POS.
00:35:27And suddenly Harley's efforts, including the Caltech tunnel fairing, made the Triumphs obsolete.
00:35:37Just don't bother.
00:35:40Ride a Cushman.
00:35:42You might do as well.
00:35:45Anyway, streamlining done carefully can result in gains.
00:35:54But they're going to be relative to that flat plate of plywood because the motorcycle is so constrained by those
00:36:01rules.
00:36:03So much so that John Britton came to the conclusion that the main variable in motorcycle streamlining was frontal area.
00:36:13Reduce it.
00:36:15Yeah.
00:36:16He took the lower fairing off on that 20 mile straightaway where all the white helmet guys go in New
00:36:23Zealand and picked up speed.
00:36:27And that was the same.
00:36:28Well, it makes sense.
00:36:29Air is getting going between the rider's lower legs and the engine.
00:36:34And there isn't this big thing down there plowing air.
00:36:39Yeah, that was the same conclusion that the Caltech guys, when Harley did the midget, Don Emdy put that story
00:36:46together for us.
00:36:47But they reduced the frontal area.
00:36:50And that was what they said principally was the advantage was reducing.
00:36:54That was the obsession in the tunnel was to reduce frontal area as the first big step.
00:37:01And that was the Harley-Davidson midget, which you can read on magazine.cycleworld.com.
00:37:09But they just made the tiny wheels.
00:37:12They lowered the bike just to make the whole.
00:37:1416s.
00:37:14Yeah.
00:37:15Yeah.
00:37:15Just to make it smaller.
00:37:18So we should switch to a consideration of the devices being used in MotoGP at this point.
00:37:27Would you agree?
00:37:28I agree.
00:37:30Okay.
00:37:32What we see is, first of all, downforce wings or winglets attached to or near the fairing nose.
00:37:43And the purpose of these is not to exert downforce to increase tire grip in corners.
00:37:49Because when the motorcycle is at 60 degrees, 63 degrees, 65 degrees, any downforce is more pushing the motorcycle off
00:38:02the turn,
00:38:04making it go wide, than it is pressing it down against the pavement.
00:38:08So the real purpose of those wings and winglets is to keep the motorcycle from wheeling in fifth gear and
00:38:24having to close the throttle to keep the front wheel steering.
00:38:30You're just a little helping hand that presses the front of the motorcycle down enough to overcome the tendency of
00:38:38the motorcycle to blow over backwards.
00:38:41And Mike Baldwin and other riders have spoken to me about wheeling over a hill crest at high speed and
00:38:50having to go for the rear brake because the front wheel wasn't coming down.
00:38:57I like that one.
00:38:59I like that one.
00:39:00Real stuff happening.
00:39:02Yeah.
00:39:02Anyway, that takes care of that whole nose business.
00:39:05That's what it's for.
00:39:06It isn't for in-corner downforce.
00:39:08It's to allow the use of more power in higher gears without having the front end go light and lose
00:39:17stability.
00:39:21So the next gizmo is fairing side panels that are so angled that when the motorcycle is at full lean,
00:39:32that these panels are parallel to the surface of the earth and form a venturi that can generate downforce.
00:39:42Now, this is going to tend to increase the motorcycle's angle of lean,
00:39:46so the rider is going to have to cope with this.
00:39:50Oh, it's doing something unusual.
00:39:52Oh, that didn't work.
00:39:54Maybe they say it takes some getting used to.
00:39:58Um, and why not?
00:40:05The air is moving.
00:40:07It has mass.
00:40:08You can generate forces with it.
00:40:10Let's give it a try.
00:40:14And small scoops located on either side of the fairing, uh, front edge of the fairing at about axle level,
00:40:22which then become ducts that go down underneath.
00:40:25When the motorcycle is operating on the fairing, on the fairing, on the straightaway, the ride height is at low.
00:40:34Oh, and that means that a flat bottom on the fairing is another prospective, uh, venturi.
00:40:46If only we could get air to it.
00:40:48We can't because the front tire's in the way.
00:40:51Oh, let's put intakes to some little ducts and run the air down there and see if it helps.
00:40:58They keep doing it.
00:41:00So either I like the way it looks or it's to some extent it works and all power to them
00:41:10for trying something because this is not a contest to see who can design a motorcycle that looks most like
00:41:18something Agostini wrote in 1966.
00:41:24This is not vintage.
00:41:26It's supposed to be racing.
00:41:31So the, uh, those so-called downwash ducts are trying to use.
00:41:37And of course, when the motorcycle is photographed, you usually don't see it at minimum height, except when they're doing
00:41:43practice starts, which is how the whole thing started in the first place.
00:41:48So, uh, item, um, number four, a spoon or small airfoil array located just ahead of the rear tire where
00:42:02it looks like if it moved aft a little bit, it would be, it would run itself over.
00:42:08I don't have any idea what that does.
00:42:10Some people say, oh, it blows cool air on the tire, but a big problem with the rear tire has
00:42:17always been lack of grip, not too much.
00:42:23So, usually lack of grip results from cooling off on the straightaway.
00:42:30And Dunlop published, and I can't find my copy, a diagram showing tires temperaturing up as they enter corners.
00:42:44Because tire temperature is a strong determinant of tire grip, there is a thing that rubber and other elastomers are
00:42:55subject to, which is called the glass transition temperature, T sub G.
00:43:01T sub G, more science.
00:43:05And the glass transition temperature is a temperature at which the rubber becomes hard and inflexible.
00:43:11It turns out that if you can raise the T sub G to something close to the operating temperature of
00:43:20the tire, you can be in a, in a not quite, uh, stiff range of rubber flexibility that generates a
00:43:31lot of internal friction, hysteresis, which creates grip.
00:43:37This is the wet grip that all the manufacturers talk about, which is just secret talk for good, good tires
00:43:46traction under all conditions.
00:43:51So, cooling off the rear tire, uh, I can't, I don't get that.
00:43:56So, I just, it's a cold case.
00:43:59I'm, I'll think about that later, like Scarlett O'Hara said.
00:44:05Various forms of streamlining applied to fork tubes, calipers, uh, brake discs, what have you.
00:44:12This is to get rid of the appalling load of excrescences that the 1958 rules burdened our sport with.
00:44:23But if you've got the, you've got the tunnel paid for until five and you've been through the program, get
00:44:30the modeling clay and let's start slapping it on there and seeing what happens.
00:44:35If we fill in this and we fill in that tape cardboard around the fork tubes to make a, an
00:44:43airfoil section out of them.
00:44:45Um, and that's what you see happening now is that complicated shapes, no doubt made by additive manufacturing techniques, uh,
00:44:56AKA, uh, 3d printing are covering up the ugly excrescences and maybe having an effect.
00:45:10Well, various forms of shrubbery affixed to the rider's seat back.
00:45:17Um, and we have the stegosaurus plates, arrays of jutting airfoils.
00:45:23Um, and I suspect that, uh, this is another area where, um, a little extra downforce when the motorcycle is
00:45:33at lean and the rider is feeling for the grip to get off the corner, a little helping hand, even
00:45:40a few pounds like five could make such a difference.
00:45:46Um, and for at least five years now, everyone, not just, uh, Yamaha has been complaining about, well, we'd really
00:45:56like to have more rear grip.
00:46:00Now the coming of variable ride height has utterly changed motorcycle, uh, GP motorcycle, motor GP braking.
00:46:10Because it used to be that Marquez rushed up to the corner, brake like a madman with the rear wheel,
00:46:18just hovering in the air, and then started to lean the motorcycle over and let the rear tire drop on
00:46:23the ground already sliding on the pavement.
00:46:29Today, people are having to use the rear brake.
00:46:34Well, doesn't, isn't, there's no point in that.
00:46:36I mean, if you can get the front brake to lift the rear wheel, then that's all the braking there
00:46:40is.
00:46:41Trying to use the rear wheel for a brake, that, that's not going to help.
00:46:44But it is going to help because there's such a thing as initial braking.
00:46:49When you first begin to brake, the front tire is not up to temperature.
00:46:55So, if, if you want maximum braking, you're going to have to feed in some rear brake and coordinate the
00:47:09whole thing so that it works out looking like you have a mystical ability to get off the corner.
00:47:16There is some rear grip.
00:47:18How are you going to get it?
00:47:19And all of that shrubbery on the seat back appears to be intended to give that little helping hand.
00:47:29Now, when you see the rider tucked in, you know that all of those little airfoils and so forth are
00:47:37probably in separated airflow and have very little effect.
00:47:43But when they're supposed to help you is when the rider has moved the entire torso off the motorcycle to
00:47:50the inside and the airflow comes over the screen and there's the seat back array fully exposed.
00:47:58So, good one.
00:48:01And now, the mysterious rubber-lipped oval armrest holes on the Aprilius.
00:48:10I was waiting for this, Kevin.
00:48:12I was waiting for this because it's so interesting.
00:48:15It is interesting because clearly what happens here is that when the rider is cornering, he's not tucked in.
00:48:29And so, those holes, which appear to be three or four inches long and maybe a couple of inches wide
00:48:36and have what looks like a rubber seal lip, probably something that comes off of an alpha door in the
00:48:45junkyard.
00:48:46Hey, here's a piece.
00:48:47Give me those scissors.
00:48:50It just happens to fit.
00:48:53All kinds of the most marvelous analogies are being drawn, and by that I mean stretched, to accommodate the view
00:49:03that these are control holes like those used in Formula One for some kind of device that could stall the
00:49:12rear wing array to increase top speed on the straightaway when you don't need downforce.
00:49:17Because your tires, because your tires are 40 inches wide or whatever it is now.
00:49:22Rollers, not tires.
00:49:26So, where is the duct leading from these holes?
00:49:31Where does it go?
00:49:32It goes forward where it gathers fresh air from the stagnation zone behind the front tire and just above the
00:49:43radiator, I think, on either side.
00:49:46Other ducts, are there other ducts that plugging those holes up when you're tucked in and your forearms are sealing
00:49:55against those rubber lips?
00:50:00We can't see, so we don't know.
00:50:04Yeah.
00:50:04So, then I thought, what special problem does Aprilia have that its riders complain about constantly cooking the rider?
00:50:17And then I thought, what if those holes deliver fresh air from the stagnation zone at 0.7Q, and there
00:50:29is an open weave section sewn into the rider's leathers that fits up against that lip, and it blows cooler
00:50:36air into the leathers, much in the way that the leather's drying systems that some teams had a few years
00:50:43ago operate.
00:50:44A blower is going, and here's this thing looking like a rider filled with helium.
00:50:51Very popular at Suzuki 8-Hour when I was there.
00:50:54Oh, yeah.
00:50:55But all the factory guys, you'd see all the castrol suits laying inflated on the floor.
00:51:01Big fans blowing them up.
00:51:03Good stuff.
00:51:04So, I don't insist that this is the true purpose of these devices, but it makes sense to me.
00:51:13You think about it and see if it makes sense to you.
00:51:16And, of course, perhaps they'll reveal something that none of us has thought of, and that'll be even more entertaining.
00:51:22More interesting.
00:51:23Yeah.
00:51:23It is such a fascinating thing, just that oval.
00:51:27And as you're tucked in, you're putting your arms down on the fairing.
00:51:32Yeah.
00:51:33Zook.
00:51:37Well, of course, another thing that has been done in Formula One, there's a lot of energy in the exhaust.
00:51:46And Formula One cars used to use the exhaust energy to blow the Venturi tunnel.
00:51:55And when I had my seventh birthday, my dad took me to New York, and we flew down there on
00:52:01a Convair twin, a pair of 18-cylinder Pratt & Whitney 2800s.
00:52:11And extending back from each engine nacelle were these big tubes.
00:52:16And my dad told me the exhaust pipes from the engine terminate right at the entrance to those tubes, and
00:52:26the rush of exhaust gas at high speed pumps air through those tubes to cool the engine, greatly reducing the
00:52:35cooling drag in flight and increasing the top speed.
00:52:40So, a motorcycle doesn't have a Venturi unless it's leaned over, or unless it's upright, and it's a minimum ride
00:52:49height, that sort of skateboard underneath that forms the bottom of the fairing.
00:52:58So, where's the Venturi that can be stalled, or where's the, I'm not sure.
00:53:05So, this stuff is delightful to me, because clearly there are a lot of people thinking about this now.
00:53:11Now, Ducati kind of started the ball rolling, but if you look back in history, you could see that downforce
00:53:19winglets were tried by Suzuki on their 500.
00:53:25There was a fellow who put a wing, it looked like a big dustpan, up on struts behind the rider.
00:53:35And I don't know what its purpose was, but it had variable incidents.
00:53:40Now, variable incidents is not permitted in MotoGP, but Formula One, which is sort of the big brother in this
00:53:53business, is now permitting some variable incidents.
00:53:57So, who knows what will happen next, because, of course, if you have little stubby winglets that have an L
00:54:06over D, lift over drag of three, it means that for every pound of downforce you generated, you're generating one
00:54:14-third of a pound of drag.
00:54:18And at 220 miles an hour, that's a fair amount.
00:54:23Okay, so you make those mustachio wings that the Yamaha and the Aprilia have, an array of three of them,
00:54:32usually, kind of like what you see on the front of Formula One.
00:54:37Maybe they have a much better lift over drag, six, seven?
00:54:42I don't know.
00:54:44My rule of thumb isn't working.
00:54:47But it means that you could get, potentially, more downforce for a given amount of drag with longer, narrower wings,
00:54:57aspect ratio.
00:55:00Because then the tip region, where the losses are, becomes less important in relation to the whole wing.
00:55:10So, it would be very nice to be able to vary the incidence of these wings so that they didn't
00:55:18produce, they produce hardly any drag at high speed.
00:55:22It was that Chaparral 2G, I think, was one of those.
00:55:26Yeah.
00:55:26The Can-Am car with the strut on it that could change the angle of the wing.
00:55:31Pretty neat.
00:55:31There's a great photo of a Formula One grid at the height of the wings on stilts movement and is
00:55:40just so silly looking.
00:55:41All these spindly little stilts sticking up with these boards, aero section planks being carried on high.
00:55:55Why put them way up there?
00:55:57Because the airflow is cleaner.
00:55:59It is less affected by the car ahead.
00:56:03So, this whole thing with the aerodynamics is tantalizing because of the high speed involved.
00:56:12But the advertising people who have to sell these sport bikes think that their sport bikes would look great with
00:56:21stuff attached to them that really doesn't have much effect until you're going 150.
00:56:28The rest of the time, you're just lugging it around.
00:56:31It's messaging, Kevin.
00:56:33It sure is.
00:56:34It's messaging.
00:56:35It sure is.
00:56:36I'm up to the minute here, folks.
00:56:38I am with it.
00:56:38Well, the supersonic, the whole supersonic look that has overtaken, you know, hard edges and all these, you know.
00:56:45Yes.
00:56:46It's supersonic, you know, our world is dramatically subsonic.
00:56:53Yes, it is.
00:56:54Tony, Tony, Tony, he worked at Buell and he had an entire career in Indy as a wing person.
00:57:03And his source document was like a NACA book from the 30s because it was all subsonic wing profiles.
00:57:15All those subsonic airfoils, yes.
00:57:16They did.
00:57:16Abbott and Donenhoff.
00:57:19And so he was like, yeah, my, I, you know, it was a great book.
00:57:22And we'd try different wing, you know, airfoils and, you know, we're turning them upside down because it's downforce.
00:57:29They were thinking of flight, but that's what Tony did.
00:57:32And so we have those nice soft curves.
00:57:35And that's really what our bikes ought to look like is those, you know, bird-like or fish-like curves.
00:57:42You don't see fishes looking like F-22s.
00:57:47Yes.
00:57:48With those angled forward intakes on either side of the fuselage.
00:57:52So that work at rearing up angles of attack.
00:58:00But that's, that looks hot.
00:58:02And new.
00:58:03And the Hawker Hunter, which is all Jaguar XKE, sinuous curves, looks old and drab.
00:58:13So the MotoGP guys have to make it work.
00:58:16Otherwise, it's just a drag.
00:58:20Well, I liked your Convair discussion because it's one of my favorite planes.
00:58:24There's one, there's Convair down at the airport where I go on the weekend sometimes at Chino.
00:58:31Yes, sir.
00:58:32And what I like about the cowlings is they open like the petals of a flower.
00:58:36Oh, yes.
00:58:38You're not unscrewing things and taking off these huge cumbersome things.
00:58:41They're on hinges.
00:58:42And it just opens like a flower.
00:58:44Like the bottom one comes out and then the top two kind of go up like this.
00:58:48So you have this.
00:58:48And there's struts that hold them there so they don't close on your fingers when the wind goes.
00:58:52Oh, so you just pop the hood, get in there, do your thing, close her up, hit it.
00:58:58Yes.
00:58:58But those ducks you're talking about are playing.
00:59:02And, of course, that was the ejector, ejector cooling.
00:59:07A steam ejector was used to drive feed water into boilers against the steam pressure.
00:59:20Great stuff.
00:59:24But the people who think about this all the time, the aerodynamics people, here's a whole new field for them
00:59:32and they're having a ball.
00:59:35And I don't mind it at all.
00:59:37Well, I've got plenty of pictures of Halewood on a 1960s Honda.
00:59:45That was then.
00:59:46It was a tremendous advance in power generation through extreme RPM.
00:59:54The motorcycles didn't handle very well, but they were fast.
00:59:59And now we have a different, we've paid attention, and I mean close attention, to engine design, to suspension design.
01:00:15The suspension revolution started in the mid-70s with the revelation that compression valves were becoming rigid obstructions at high
01:00:26damper rod speeds.
01:00:29Which was why people had to make the upshift when they came out, turn five, on to the banking at
01:00:36Daytona.
01:00:38Because if you had the power on, you were going to have an upsetting impact.
01:00:46And great developments have taken place in tires.
01:00:52In 84 came the radial revolution.
01:00:55In 74 came the slick tire revolution.
01:00:59In 92 came the silica reinforcement revolution.
01:01:06Tires began to be, they automated the production of radial tires around 2000.
01:01:17And it's been a wonderful progress and enormous gains have been made.
01:01:24But all this while, aerodynamics has sort of been sitting there because that 1958 rule said, hands off all these
01:01:31things.
01:01:32Here's a big, here's a big long list of things you can't do.
01:01:35Or as Roger Edmondson liked to put it.
01:01:41Modifications not specifically mentioned here are strictly forbidden.
01:01:47Everything is forbidden.
01:01:49If I didn't mention it.
01:01:51Well, I liked the early, I liked the early super bike rules.
01:01:54Again, going to my recent time with Steve McLaughlin and John Ulrich.
01:01:57And they, they left a lot open because they knew a lot needed to be done.
01:02:01Because we were racing like motorcycles unfit for purpose.
01:02:05So the rules were, rules were broad.
01:02:09Repositioning of the shocks, which Udo Guido interpreted as, I'll reposition one of them on the BMW to the shelf.
01:02:15And so you could reposition your, you could reposition your twin shocks, but would they just stretch the interpretation?
01:02:21And when got rid of two shocks and put one of them in the middle, just as it was on
01:02:27a TZ 750 in the later models.
01:02:33So the Japanese took note of all the tremendous work that had to be done to win those first era
01:02:42sit up super bike races.
01:02:44And they re-engineered the second era of bikes to benefit from the experience in GP racing that they all
01:02:55had by that time from 83 onward.
01:02:59And, uh, it was a very important step forward.
01:03:04These were motorcycles that were raceable out of the box.
01:03:08You might want to change the front fork dampers and the tires and the brake pads.
01:03:14But otherwise that was it.
01:03:17So, uh, those motorcycles didn't need all that welding and gusseting and throwing away the suspension and buying others.
01:03:30They were usable right out of the crate.
01:03:34And that was a giant step forward.
01:03:36Well, gosh, those are 90 S's, you know, uh, Udo Gito moved the entire powertrain forward.
01:03:43There's a spacer on the output for the drive shaft.
01:03:47It's about that long.
01:03:50That keeps the drive shaft in the right orientation, you know, distance wise.
01:03:54So they moved the motor forward and they, you just put a cookie in there that connected the output to
01:03:59the, to the drive shaft.
01:04:01So, cause the engines slid far enough forward that the cylinder is hitting the front down tube.
01:04:07Yeah.
01:04:08We, we've run out of room.
01:04:10Well, I, I read, uh, I went up into the, into the engineering library, which is in that dome that
01:04:19MIT has.
01:04:20I was working there as a technician, a lowly technician.
01:04:24Uh, and it described in, in, in the Japan society of mechanical engineers.
01:04:32It, it described motorcycle stability testing on a moving belt.
01:04:37And they discovered that as they moved weight forward, stability was increased.
01:04:45And at one point they talked about a less successful experiment that they made.
01:04:49And under result, it said, the doll is overthrown.
01:04:55The doll being, being a human like dummy placed on the motorcycle to have similar weight and arrow characteristics.
01:05:05The doll is overthrown.
01:05:07Yes.
01:05:07The doll is overthrown.
01:05:09Uh, same, same data out of, uh, Buell many, many decades later.
01:05:14Um, you know, the, the Buells were going very short trail and very steep rake.
01:05:19They were sort of 21, 22, uh, with trails that were quite short to something in three ish, you know,
01:05:27very, uh, very short.
01:05:29And it was, uh, I was talking to Steve Anderson, who was a longtime contributor for us, an engineer himself,
01:05:35and also worked at, at Buell EBR.
01:05:38And he said, yeah, the more weight we put on the front, the more aggressive we could be with our
01:05:42steering geometries.
01:05:43And, and they were stable.
01:05:45I have to say they were, they were light steering and stable, um, the Buells.
01:05:49Uh, and if you look at this, uh, the other way, turn the telescope around, you see, uh, the, uh,
01:05:57bevel drive Ducati with its engine necessarily far back because the front cylinder was at a 15 degree angle from
01:06:07horizontal.
01:06:08So it acted as a spacer pushing the crankcase back against the rear tire.
01:06:13So what geometry did they end up with?
01:06:1631 degrees and four and a half inches.
01:06:21So sort of touring on the way to chopper hood.
01:06:27Yeah.
01:06:27I think if I'm starting with a frame for my, you know, notional homemade sport bike, I'm going to stick
01:06:33with a 24 and something around four inches.
01:06:37It's pretty, it's pretty pleasant.
01:06:39That's about where it is now.
01:06:40Pretty pleasant geometry.
01:06:42It's a, it's real workable.
01:06:44Does, does all the things you want.
01:06:45I might go a little bit longer than your 55.5 or your 54.9 as you do on your
01:06:50sport, sporty bikes.
01:06:52I go to 57 just cause I'm that kind of person, you know, but I'm also a big, I'm a
01:06:57big believer in flywheel mass.
01:06:59You know, we keep taking all this flywheel mass off and I actually, I find flywheel mass quite workable.
01:07:05I'll go ahead and say Velocet.
01:07:07I have the, I have the old flywheels, which are the full circle flywheels, but I have the hot cam.
01:07:14And so what I, I think I have an advantage.
01:07:16The way that bike runs, I think it is an advantage.
01:07:19Yeah.
01:07:19Because there's less crankshaft speed variation.
01:07:22Yeah.
01:07:22And the later, the later cranks were more pork choppy.
01:07:26Yep.
01:07:26And one of, you know, our friend Gary Braun over there at Millennium is, is building cranks for flat trackers
01:07:33and he's just piling on.
01:07:36He's making the 450 single cranks, full circles, big welds of chunks, all machined and beautifully balanced as he does.
01:07:46Fascinating.
01:07:47Well, that's not aerodynamics at all, is it?
01:07:50No, but while you were speaking of it, I was thinking of the aerodynamic experiences that we all had as
01:07:56children, namely creating winglets with our hands out the car window.
01:08:04And you discovered that the effect was increased with speed.
01:08:09Oh, yeah.
01:08:10Out close to the window and then banking it in, giving yourself a nice face full.
01:08:16Yes.
01:08:16How I miss the wind wing.
01:08:18You know, I have, I have cars with wind wings.
01:08:20I have my truck, my 89 Ford has wind wings, my, my Jag, which I'm driving today, little, little quarter.
01:08:27Yes.
01:08:28Oh, they're so effective.
01:08:32Yes, especially in Kansas, if you don't have air conditioning.
01:08:37Especially in Kansas.
01:08:39Well, I, I have not the fondest memories of crossing Kansas in mid, midsummer, while one of my fellow van
01:08:51occupants insisted upon smoking.
01:08:55Oh.
01:08:57I thought I was going to have to stop at one point, but I manned up.
01:09:03So, you know, I think the, I recall flying on airliners as a kid, having a, having a smoking section
01:09:11inside an aircraft.
01:09:12That was pretty, that was pretty hilarious.
01:09:17Well, that's not aerodynamics either, but.
01:09:22People write in and they say that digressions are welcome.
01:09:26Yep.
01:09:27So, we believe you.
01:09:29Yeah, we do.
01:09:30We listen.
01:09:30As crescentes are not.
01:09:34Well, that's it, folks.
01:09:36That's aerodynamics.
01:09:37Thanks for listening.
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01:10:12And that's it for now.
01:10:14We'll catch you next time.
01:10:14We'll catch you next time.
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