Author Topic: Physics investigations on Stunts  (Read 13731 times)

Overdrijf

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Re: Physics investigations on Stunts
« Reply #45 on: April 29, 2009, 12:09:28 AM »
Wow ones again. You really are good at this. So the drag really has nothing to do with it, and my kart has a very special unreachable powergear... :)

Overdrijf

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Re: Physics investigations on Stunts
« Reply #46 on: April 29, 2009, 12:52:06 AM »
By the way, I'm probably sounding spoiled now, but it appears you where so exited about the second set of dimensions that you didn't mention were the car-to-car set is located. :)

Duplode

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Re: Physics investigations on Stunts
« Reply #47 on: April 29, 2009, 07:07:45 AM »
I can not imagine you did not find this out in a dream. :)

Not quite, it was rather like one of those situations when lots of apparently unrelated informations suddenly start to make sense together when you stumble at the missing piece  :)

Only one distinction missing: speed difference between ACURA power gear and Indy power gear.


This distinction was, in a way, already pointed out - by you  :) Many years ago you wrote, and a few years later I read, a "Tips for Newbies" article in which the powergears of Indy and Acura were called "flexible", in opposition to the GTO and Vette ones. That is the fundamental distinction: "rigid" (or boring :)) powergear, the most common kind, works exactly the same for all cars that have it - to reach it you have to be at/above 225mph and the car must not have enough engine power to keep accelerating on its own by then. Flexible powergear, on the other hand, can be reached below the flat track top speed, and the minimum launch speed depends on the balance of forces acting on the car (including engine power, gear ratios, aero drag, steepness of slope, etc.). The launch speed for flexible powergear can potentially be much lower than 225mph, a fact that is evident on any Acura/Indy lap... The speed of the car when in PG is the speed of the car at maximum rpm in the (final) gear, so that's why Acura and Indy are different. If Acura had a value for mass that would give it rigid PG, however, it would never reach it, as the top speed is below 225mph (that is exactly the case for Audi, by the way). I like "rigid" and "flexible" terminology, guess I'll stick with it  :)

So the drag really has nothing to do with it, and my kart has a very special unreachable powergear... :)

Drag does not affect the kind of powergear indeed, but it if the powergear is flexible it changes the minimum speed (higher drag leads to easier-to-reach powergear). You mentioned to be using mass=15 and drag=19. 15 is a flex-PG value (same as Indy), and 19 is quite low, so the minimum speed might be well above 156mph (have you tested going through a loop, though?  :))

By the way, I'm probably sounding spoiled now, but it appears you where so exited about the second set of dimensions that you didn't mention were the car-to-car set is located. :)

Oh my bad, maybe I shouldn't have gone so far in skimming detail on that post  :D The range of interest is 0EEh - 0F3h, and values are in the usual x-y-z pattern. I will (try to) start writing some of this stuff (and more) to the Wiki now, so stay tuned  ;)

Overdrijf

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Re: Physics investigations on Stunts
« Reply #48 on: April 29, 2009, 09:14:56 AM »
So the drag really has nothing to do with it, and my kart has a very special unreachable powergear... :)

Drag does not affect the kind of powergear indeed, but it if the powergear is flexible it changes the minimum speed (higher drag leads to easier-to-reach powergear). You mentioned to be using mass=15 and drag=19. 15 is a flex-PG value (same as Indy), and 19 is quite low, so the minimum speed might be well above 156mph (have you tested going through a loop, though?  :))

Not 15, 5. That's actually just a bit on the heavy side for a "realistic" superkart. :) So that would make it rigid. But no, I haven't tested a loop yet, I should probably still do that. (But I'm too lazy to do that before getting the new dashboard to work, and that's gonna take a few days.)
« Last Edit: April 29, 2009, 09:17:07 AM by Overdrijf »

CTG

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Re: Physics investigations on Stunts
« Reply #49 on: April 30, 2009, 06:18:21 PM »
Duplode, may I have a question? How do you have so much energy for this Stunts research plus high level racing in the same time? This work is amazing!

Duplode

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Re: Physics investigations on Stunts
« Reply #50 on: April 30, 2009, 06:25:11 PM »
Duplode, may I have a question? How do you have so much energy for this Stunts research plus high level racing in the same time? This work is amazing!

Thanks - in my case, I think one thing feeds the interest for the other, and vice-versa  :)

Overdrijf

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Re: Physics investigations on Stunts
« Reply #51 on: April 30, 2009, 06:37:16 PM »
O, I forgot to mention, I tried the loop. As predicted by your formula, it does not powergear (for having a rigid/boring powergear and limited top spead).

Duplode

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Re: Physics investigations on Stunts
« Reply #52 on: May 11, 2009, 05:08:08 PM »
You can already read full report on how to control PG when tuning a car at http://wiki.stunts.hu/index.php/Power_gear_bug ...

CTG

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Re: Physics investigations on Stunts
« Reply #53 on: August 03, 2013, 05:59:10 PM »
Daaaaaamn, I just realized that I use a bad theory for air drag limited top speed calculations. It worked for all my custom cars, except Veyron: it should reach 245 mph without powergear, but somehow it accelerated only up to 237. Problem solved. Sometimes I should read the instructions carefully... :D
« Last Edit: August 03, 2013, 06:02:00 PM by CTG »

gagarin

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Re: Physics investigations on Stunts
« Reply #54 on: April 02, 2015, 03:25:13 PM »
OFF: just found this spare account, forgot about it completely... (guests cannot see the memberlist)

ON:
Have you ever noticed that car size ratios are far from real life values? Duplode described the height anomaly and that some cars are just way too big. But their relative size is weird, too. Audi Quattro and Countach have almost the same length in real life - while in Stunts, difference is 22 units (>1.3 m).

Stunts Wiki says 1 pt = 0.2 ft = 6.1 cm (confirmed).

Lamborghini Countach
Real life size: 420/200/107
Stunts size: 104/38/18; which means: 634/232/110
Difference in %: +51.0 (!!!) / +16.0 / +2.8

Way too long and flat.

Lancia Delta Integrale
Real life size: 390/177/136.5
Stunts size: 79/34/25; which means: 482/207/153
Difference in %: +23.6 / +16.9 /  +12.1

Ratios are more or less fine.

Lamborghini LM002
Real life size: 490/200/185
Stunts size: 88 (without spare wheel)/34/31; which means: 537/207/189
Difference in %: +9.6 / +3.5 /  +2.2

The largest car from the pack in real life - very undersized in the game, compared to other cars.
« Last Edit: April 02, 2015, 03:38:13 PM by gagarin »