How fast can a scooter really go? Dyno Data & Sprint Sim....

[soulsurfer]

Interesting stuff.
What relationship does torque play in reaching higher speeds?

[drunkmunkey6969]

Interesting stuff.
What relationship does torque play in reaching higher speeds?

Good question. Both mine and Darrell's dynos have the same very BASIC rolling resistance curve option, which can be over-layed onto graphs, and if you know the rolling resistance values you can set the curve to cross and give a suggested theoretical MPH reading. This function is VERY basic as i say, and not nearly as comprehensive as the Dynabike software Darrell is using here.....i only draw reference to the MJP version as they suggest terminal top speed is where the Torque curve meets the resistance curve, not BHP. So interesting question.....

[willwander]

...You could argue that if you can't get in that position and have poor flexibility, having a low sports seat is a bad idea, and you'd be better with a higher seat to enable you to get a flatter back and lower shoulders...

Yep.

Cool post, cheers. I might put up some pictures of 'Tape gate'

[drunkmunkey6969]

Cool post, cheers. I might put up some pictures of 'Tape gate'

The one where you went slower? lol

Do post the pics, it sounds funny

[Arcadia]

....you can do a quick recky of what would be needed, pick either the group 6 or road scooter graphs then look at the drag and friction curve to the power and speed graph lines.

eg - for the group 6:

40 hp = 112mph
50 hp = 122mph
60 hp = 130mph

There are, on the day, variables to consider. eg - head or tail wind and the graphs are simply adjusted with these different inputs...

So Keith Terry had 60+ bhp? Is that what we are saying here? Surely there is a mistake in either your calculation or Keiths time card? What is the next best time Keith ever did in the past 20 years? Even close?

And i've been thinking about the Madspeed speed of 138mph, that means he has 70+bhp? However, i think Madspeed have made a genuine error and confused MPH with KPH. I say this genuinely, because if you look at their website is says 1/4 mile 13.9 seconds @ 138.5 mph. However a 13.9 second 1/4 mile fits in much closer with a speed of 86mph which is what 138kph converts to.

Whats more worrying is that Madspeed say thiers is the second fastest scooter....what is the first? (presuming we are talking classic scooters etc).

[Avantone]

So Keith Terry had 60+ bhp? Is that what we are saying here?

No. I don't know how much he had, but then it wasn't either a standard body or Gp6 and would of had significantly less drag.

[warts]

Lots of emphasis is put on trailing edge aerodynamics where there are restrictions on the changes permitted - either practical, cosmetic or regulatory.

A bluff front with streamlined rear will have lower Cd's than vice versa, ie swoopy front and disruptive and turbulent rear.
Which is what I think Avantone is saying viz a viz adopting the position?


Way back, before Audi's were another repmobile, they spent a lot of time trying to get one of their vehicles below some arbitary Cd or other. Having spent a bob or two, in the end taping over all glazing and panel gaps plus removing all discontinuities yielded best swoosh for the buck/Deutschmark as was.

[drunkmunkey6969]

So Keith Terry had 60+ bhp? Is that what we are saying here?

No. I don't know how much he had, but then it wasn't either a standard body or Gp6 and would of had significantly less drag.

Fair point Tone about less drag than a Grp6, they both appear to use Vega front leggies, but maybe the tail piece and lower headstock height help a little bit?

So the question at this point is.....can the aerodynamics of Keiths machine reduce the BHP requirement sufficiently from a projected 60bhp to backup the 132mph speed?

[drunkmunkey6969]

What is the next best time Keith ever did in the past 20 years? Even close?

Interesting question, and i have no idea.

One of the regular sprint-goers might be able to answer......

[fairspares]

What is the next best time Keith ever did in the past 20 years? Even close?

Interesting question, and i have no idea.

One of the regular sprint-goers might be able to answer......

This is a great thread . Im in the process ( a slow one at that) of putting together all the 1/4 mile and flyer times and speeds i can find in scootering magazines since early 80s and what i can find on website and forums . looking at some of the info i have upto 1994 Keith got his sprinter down to low 13 sec 1/4 times @ around 103+ mph with his best ever time of 12.70 at RAF sculthorpe and a flying 1/4 on same day @ 113.78 mph ,from looking at photos of that day he had no front fairing just frame tube and a bike race style seat , il have to check to see how he did after this year