SuzukiSavage.com - 100 mph possible?

LANCER

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Re: 100 mph possible?
Reply #30 - 12/07/12 at 06:37:27

I found a chart in one of my son-in-laws flight training manuals, "Fundamentals of Aerodynamics" with a DRAG vs VELOCITY chart. The curve is similar to the one posted by Dave but the slope of the curve is longer. Keep in mind this is aerodynamic only.
Drag is the vertical component and velocity is the horizontal component.
Aerodynamic drag does not noticeably rise until about a quarter of the way across the velocity axis.
Drag doubles at the 40% point on the axis.
At 60% on the velocity axis the drag doubles again.
The last 40% of the velocity axis takes the aerodynamic drag coefficient vertical.

This is just aerodynamic drag. Mechanical and frictional drag from a bike and the road add other significant components of drag.

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gone fishing Full Member Offline Posts: 152 Gender:	Re: 100 mph possible? Reply #31 - 12/07/12 at 06:37:33 gone fishing
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Gyrobob

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Re: 100 mph possible?
Reply #32 - 12/07/12 at 07:02:11

LANCER wrote on 12/07/12 at 06:37:27:

I found a chart in one of my son-in-laws flight training manuals, "Fundamentals of Aerodynamics" with a DRAG vs VELOCITY chart. The curve is similar to the one posted by Dave but the slope of the curve is longer. Keep in mind this is aerodynamic only.
Drag is the vertical component and velocity is the horizontal component.
Aerodynamic drag does not noticeably rise until about a quarter of the way across the velocity axis.
Drag doubles at the 40% point on the axis.
At 60% on the velocity axis the drag doubles again.
The last 40% of the velocity axis takes the aerodynamic drag coefficient vertical.

This is just aerodynamic drag. Mechanical and frictional drag from a bike and the road add other significant components of drag.

Mechanical and frictional "drag" increase directly with velocity. A body traveling through air (a gaseous fluid) has the drag increase with the square of velocity.

The charts in flight manuals take into account that aircraft have coefficients of drag well less than that of a Savage, and then they add in things like form drag, parasite drag, interference drag, drag caused by lift, etc.

Our situation is simpler. The main component is just form drag, and the drag coefficient is about 1.0. Yes, we have rolling resistance and mechanical horsepower losses, but most of what happens is due to the drag from moving a 1.0 body through a gaseous liquid. This is why it takes double the horsepower to go 85 as opposed to 60.

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Gyrobob Serious Thumper Offline Posers ain't motorcyclists Posts: 2571 Newnan, GA Gender:	Re: 100 mph possible? Reply #33 - 12/07/12 at 07:03:39 gone fishing wrote on 12/07/12 at 06:37:33: And if you look at it on paper, a bumble bee can't fly.... Where does it say this?
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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28886 L.A. California Gender:	Re: 100 mph possible? Reply #34 - 12/07/12 at 07:17:22 Gyrobob wrote on 12/07/12 at 07:03:39: gone fishing wrote on 12/07/12 at 06:37:33: And if you look at it on paper, a bumble bee can't fly.... Where does it say this? often quoted analysis by some propeller head envious of the bee's actual ability to fly. "but my propeller is as big as the bee's relatively"
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Re: 100 mph possible?
Reply #35 - 12/07/12 at 07:27:11

comparing a savage to a hayabusa would be like comparing a sopwith camel to an F-22.

From Wikipedia:

The power required to overcome the aerodynamic drag is given by:

Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome air drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW). With a doubling of speed the drag (force) quadruples per the formula. Exerting four times the force over a fixed distance produces four times as much work. At twice the speed the work (resulting in displacement over a fixed distance) is done twice as fast. Since power is the rate of doing work, four times the work done in half the time requires eight times the power.

Also:
it takes 3/4 Hp for a cyclist to go 55mph.

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Gyrobob

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Re: 100 mph possible?
Reply #36 - 12/07/12 at 07:42:11

verslagen1 wrote on 12/07/12 at 07:27:11:

comparing a savage to a hayabusa would be like comparing a sopwith camel to an F-22.

From Wikipedia:

The power required to overcome the aerodynamic drag is given by:

Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome air drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW). With a doubling of speed the drag (force) quadruples per the formula. Exerting four times the force over a fixed distance produces four times as much work. At twice the speed the work (resulting in displacement over a fixed distance) is done twice as fast. Since power is the rate of doing work, four times the work done in half the time requires eight times the power.

Also:
it takes 3/4 Hp for a cyclist to go 55mph.

Comparing a penguin to a marshmallow is like feeling your sister.

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Serowbot

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OK.... so what's the
speed of dark?

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Re: 100 mph possible?
Reply #37 - 12/07/12 at 07:51:23

Maths,... yuk...

I know this,... if I'm going 65mph, and I tuck in everywhere (body, head, knees, elbows),... I can gain 4 to 6 mph... at the same throttle...
If you have a cruiser type windscreen,.. fugetaboutit... Grin

...

Gyrobob wrote on 12/07/12 at 07:42:11:

Comparing a penguin to a marshmallow is like feeling your sister.

That's deep... Huh

...

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Ludicrous Speed !... ... Huh

...

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LANCER Serious Thumper Alliance Member Offline Savage Beast Performance Parts Posts: 10667 Oklahoma Gender:	Re: 100 mph possible? Reply #38 - 12/07/12 at 08:40:27 Yes, there are differences in the rate of increase of drag from mechanical, frictional and aerodynamic forces. All I have tried to say is that aerodynamic drag is just one of several components of drag that affect the power required to reach higher speeds for a given man/machine.
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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28886 L.A. California Gender:	Re: 100 mph possible? Reply #39 - 12/07/12 at 08:51:35 Gyrobob wrote on 12/07/12 at 07:42:11: Comparing a penguin to a marshmallow is like feeling your sister. personal experience... err no, NO don't tell me TMI.
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Gyrobob

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Re: 100 mph possible?
Reply #40 - 12/07/12 at 09:01:59

Serowbot wrote on 12/07/12 at 07:51:23:

... if I'm going 65mph, and I tuck in everywhere (body, head, knees, elbows),... I can gain 4 to 6 mph... at the same throttle...

Zackly. You just changed the drag coefficient from,... say,.. 1.05 to .995. You get more speed for less drag with the same power, or with more power for the same drag. Just plain ol' fizzix.

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Gyrobob

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Re: 100 mph possible?
Reply #41 - 12/07/12 at 09:05:46

LANCER wrote on 12/07/12 at 08:40:27:

Yes, there are differences in the rate of increase of drag from mechanical, frictional and aerodynamic forces. All I have tried to say is that aerodynamic drag is just one of several components of drag that affect the power required to reach higher speeds for a given man/machine.

Very true. Once we get into the speeds where aerodynamic drag starts to matter, it matters more and more compared to other drains on horsepower. A Savage at 100 mph has HUGE aerodynamic drag; the primary absorber of horsepower at that point.

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Gyrobob Serious Thumper Offline Posers ain't motorcyclists Posts: 2571 Newnan, GA Gender:	Re: 100 mph possible? Reply #42 - 12/07/12 at 09:09:07 It would be interesting to put a good cafe fairing (the older full coverage type) with clip ons and a smaller rear drive pulley on a RYCA conversion with a stock motor. I'll bet the reduction in drag would allow it to do the ton easily.
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Cavi Mike Serious Thumper Offline Thumper n00b Posts: 1005 Rochester, NY Gender:	Re: 100 mph possible? Reply #43 - 12/07/12 at 09:21:11 The belt would have to go completely.
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BuckRYCA

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Re: 100 mph possible?
Reply #44 - 12/07/12 at 09:22:07

Gyrobob's graph of horsepower versus speed shows that my Savage was making just over 40hp at the rear wheel when it registered a true 88mph. Bike was stock except for a richer main jet. Stock hp is advertised as ball park 30. This suggests that the CD for the stock bike may be less than 1.0.

Nonetheless, if the graph is more or less correct, then it suggests that reaching 100mph, if possible at all, would take a long stretch of road. At 88mph the front end is feeling light and vague and acceleration is modest, so running a long time with likely increasing instability is not all that enticing. The place to try it would be a track day on a closed track with a long straightaway. But it would be disconcerting to have everyone else screaming past. Lips Sealed

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