C14 Top speed vs Fjr1300 Top speed

[markjenn]

The TGV train example is a poor one. I suspect in this case weight does matter to top speed, but not with respect to the ultimate speed of the train in a straight line on level ground. It matters because the TGV is probably top-speed limited by its rate of acceleration between areas where, because of traffic, grade, and track conditions, it has to slow down, and because a heavier train adds extra stress to the tracks. For a steel-wheeled vehicle on steel rails, the extra steady-speed drag associated with a heavier train on level ground is negligible.

Bottom line is that you could make your FJR fairing panels out of steel and the resulting 2K-lb FJR would take a long time to get to top speed, but its top speed wouldn't be much slower than a stock FJR. The only difference affecting the top speed would be the increase in rolling resistance due to the extra weight and at 150-mph, rolling resistance is perhaps 5% of aero drag, so doubling it isn't going to have a large effect.

- Mark

 

[bandito]

Dude, Three Letters "TGV" the french locomotive that goes 320kph (200mph) Horsepower and Aerodynamics are ALL that matter at that speed.

How much Power does it take to move the TGV that fast? Well, it turns out it depends, among other factors, on weight. Here is a snipet from a comparison of two trains:

They are formed of two power cars (8,800 kW under 25 kV - as TGV Atlantique) and eight carriages, giving a capacity of 377 seats. They have a top speed of 300 km/h. They are 200 m (656 ft) long and are 2.90 m (9.5 ft) wide. The bi-current sets weigh 383 tonnes (422 short tons): owing to axle-load restrictions in Belgium the tri-current sets have a series of modifications, such as the replacement of steel with aluminium and hollow axles, to reduce the weight to under 17 tonnes (19 short tons) per axle.

And...

The Eurostar train is essentially a long TGV, modified for use in the United Kingdom and in the Channel Tunnel. Differences include a smaller cross section to fit within the constrictive British loading gauge, British-designed asynchronous traction motors, and extensive fireproofing...The sets operate at a maximum speed of 300 km/h (186 mph), with the power cars supplying 12,240 kW of power. The Three Capitals sets are 394 m (1,293 ft) long and have 766 seats, weighing a total of 752 tonnes (829 short tons; 740 long tons).

Given a smaller cross section, I guess it's just the poor drag coef the Eurostar has to overcome with 39% more power to attain the same 300 km/h max speed as the TGV Atlantique. I'm sure the additional 369 tonnes had nothing to do with it.

Weight matters.

Aha!! You said longer, which means a larger "wetted volume" to push through the fluid. (air) Weight affects rolling friction which increases in a linear fashion (straight line). Aerodynamics affects the fluidic drag which increases exponentially, until Mach 1 is reached, then the rules change. So yes weight does matter, but not as much as aerodynamics, and less so as the speed increases.

 

[bandito]

The TGV train example is a poor one. I suspect in this case weight does matter to top speed, but not with respect to the ultimate speed of the train in a straight line on level ground. It matters because the TGV is probably top-speed limited by its rate of acceleration between areas where, because of traffic, grade, and track conditions, it has to slow down, and because a heavier train adds extra stress to the tracks. For a steel-wheeled vehicle on steel rails, the extra steady-speed drag associated with a heavier train on level ground is negligible.
- Mark

All depends on the point we are trying to illustrate; in this case the contributions of weight compared to aerodynamic drag on top speed. here is the drag equation (find it Here at NASA)

D = Cd * A * .5 * r * V^2

Notice the Velocity is Squared, which means the faster you go the more the aeordynamic drag matters. More power is needed to GET to that top speed faster, and to overcome obstacles like hills, curves, and other exceptional events. The eurostar is narrower than the Atlantic TGV, but it is higher, maybe more hills to climb, etc etc.

BUT I would have to agree the FJR is better looking, so that is what matters the most right :lol: :lol:

 

[bandito]

OK this is the last post, but THIS ARTICLE gives a good expanation of drag on motorcycles, using a wind tunnel to compare top speeds of a Kawa ZX-12R and a 'Busa. Good reading if you got the time :smile3: If not the conclusion is ....... the Busa is faster cause it has less aerodynamic drag !!!! :yahoo: :yahoo:

 

[Ari Rankum]

Ok all you performance compare folks,
Now it is important to note that in the above tests the gtr1400 had a better 1/4 mi time by 3/10ths of a second because the FJR1300 was the AE model. I have read in other mags how the AE is a little heavier and not as fast in 0-60 and 1/4 mi times because of the in ability to shift it as fast as a true manual shift.

Are you freaking serious? May I point you to the search page? One of the most comprehensive FJR experiments ever conducted showed that the AE is capable of 5.5 shifts per second. If you're not aware of how being able to shift 5.5 times per second dramatically improves motorcycle performance, I suggest you read what downn2 had to say about it.

 

[Wicked Webby]

Ok all you performance compare folks,
Now it is important to note that in the above tests the gtr1400 had a better 1/4 mi time by 3/10ths of a second because the FJR1300 was the AE model. I have read in other mags how the AE is a little heavier and not as fast in 0-60 and 1/4 mi times because of the in ability to shift it as fast as a true manual shift.

Are you freaking serious? May I point you to the search page? One of the most comprehensive FJR experiments ever conducted showed that the AE is capable of 5.5 shifts per second. If you're not aware of how being able to shift 5.5 times per second dramatically improves motorcycle performance, I suggest you read what downn2 had to say about it.

ARI,

Well...You better let them expert racers and testers know that the AE is faster...What is going on.... they must not be riding/testing them correctly!!

Glad you cleared that up.....

:blink: :blink: :blink: :blink: :blink: :blink:

I also read that you can corner the hell out of a BUSA, if you put a good 2 foot stretched swingarm and a 250mm tire!!

:dribble: :dribble: :dribble: :dribble: :dribble: :dribble:

 

[painman]

"Quote": BLAH, BLAH, BLAH, BLAH,........Where's Odot when you need em? pm. h34r: