Sounds sensible. Any idea of approximate values for this combined MOI in a
real life situation?
Good to see I'm going in the right direction!
effective_tire_radius
Cheers,
Mike.
Best place to order is right from SAE, our publishers -- go to
<www.sae.org> and search for Milliken in the bookstore, order number is
R-146. They have the book in stock and give a decent price on shipping.
They have a lot of other books on racing too -- support small specialty
publishers!
-- Doug Milliken
Milliken Research Associates Inc.
Depends totally on the tire sizes, wheel type, etc...
Also, I'm used to working in what we call "English" units -- will
you know what to do if I give you mumbers in slug-ft^2? <evil grin>!
-- Doug
Milliken Research Associates Inc.
Good, then I was right for once :-P This tripped me up when trying to put in
rolling resistance at first. When letting the force increase with speed, the
coefficient had to be so low that it wouldn't stop for a long time. If it was
high enough to slow down realistically at low speeds, the car was seriously
deprived of top end speed. Luckily, the force remains more or less constant,
so just picking a low number worked well.
>As for aerodynamic drag, it's 0.5 * Cd * rho * A * V^2 where Cd is the drag
It's absolutely relevant! The formula you're showing gives the force from
aero drag, while the one I showed gave the horsepower. It's better to use the
one you're showing in simulation.
Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://PerformanceSimulations.Com
Hey! I could use some of these numbers! I use "English" units too. Send
'em my way if you get a few extra minutes :-)
Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://PerformanceSimulations.Com
Well, we've got vehicle models, so let's add a forward force, kill wind
resistance, put in an offset and try it. You go first ;-) Interesting though,
I hadn't thought of the vertical force torque effect that would develop.
Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://PerformanceSimulations.Com
Anyone?
TIA, Colin
you... engineer :)
-Gregor
> Also, I'm used to working in what we call "English" units -- will
> you know what to do if I give you mumbers in slug-ft^2? <evil grin>!
> -- Doug
> Milliken Research Associates Inc.
Ash
| Doug,
|
| you... engineer :)
|
| -Gregor
|
| >
| > Also, I'm used to working in what we call "English" units -- will
| > you know what to do if I give you mumbers in slug-ft^2? <evil grin>!
| >
| > -- Doug
| > Milliken Research Associates Inc.
| >
Oh, to be young again and have the time for creative abuse...<g>
If anyone does have access to the parts that they need inertias for,
I seem to remember that there was a nice write up on this cycling
site, but I haven't looked lately to see if it's still there.
<http://www.analyticcycling.com> (a very cool site, by an ex-DuPont
engineer)
> Ash
> | Doug,
> |
> | you... engineer :)
> |
> | -Gregor
> |
> | >
> | > Also, I'm used to working in what we call "English" units -- will
> | > you know what to do if I give you mumbers in slug-ft^2? <evil grin>!
> | >
> | > -- Doug
> | > Milliken Research Associates Inc.
> | >
http://www.digitaldutch.com/unitconverter/
As long as someone manages to explain me the difference between all the
pounds, I'll be just fine :).
-Gregor
> Depends totally on the tire sizes, wheel type, etc...
> Also, I'm used to working in what we call "English" units -- will
> you know what to do if I give you mumbers in slug-ft^2? <evil grin>!
> -- Doug
>http://www.digitaldutch.com/unitconverter/
>As long as someone manages to explain me the difference between all the
>pounds, I'll be just fine :).
Ruud van Gaal, GPL Rank +53.25
Pencil art : http://www.marketgraph.nl/gallery/
Free car sim : http://www.marketgraph.nl/gallery/racer/
Looks like I'll be off to the breaker's yard with a set of bathroom scales
then :-)
> Oh, to be young again and have the time for creative abuse...<g>
> If anyone does have access to the parts that they need inertias for,
> I seem to remember that there was a nice write up on this cycling
> site, but I haven't looked lately to see if it's still there.
> <http://www.analyticcycling.com> (a very cool site, by an ex-DuPont
> engineer)
> > Oh no the 'name-calling' has started <g>
> > Ash
> > | Doug,
> > |
> > | you... engineer :)
> > |
> > | -Gregor
> > |
> > | >
> > | > Also, I'm used to working in what we call "English" units -- will
> > | > you know what to do if I give you mumbers in slug-ft^2? <evil grin>!
> > | >
> > | > -- Doug
> > | > Milliken Research Associates Inc.
> > | >
Thinking about this, wouldn't the rolling resistance actually act against
the direction of the wheel's roll? Effectively this would slow down the
wheels rotation causing a deceleration of the vehicle.
