UK Karting - Notice Board (General Karting) : Re: No ! , the original qustion was...

Notice Board (General Karting)

Re: No ! , the original qustion was...
Posted by 'davidmc' on 19 Aug 2009 @ 12:27

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davidmcJoined: April 2003
Total Posts: 2
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QOT,

I'm sorry but you are simply wrong. Just look at the maths (kept simple with a fixed gear ratio of 1):

Force (at wheels) = Power / Speed
Force (at wheels) = Mass * Acceleration
Force (at wheels) = Torque

To achieve the greatest acceleration, you need the greatest Force. It follows then, that you need the greatest Torque.

What about the Force = Power / Speed equation? Greater Power also creates a greater force and therefore greater acceleration. This is true. However, in a fixed gear vehicle, Power is not independant of speed. By doubling the power output, all you've done is double the speed. In a geared vehicle you can select the "power" you output by changing gear and putting the car in a certain rev range. Since speed is fixed the greater force is given by choosing the gear that puts you at the revs of greatest power. In a CVT, Power output is totally independant of speed and therefore maximising power maximises force.

The maths says I'm right, and people's own experience says I'm right. Intuitively, we don't feel acceleration continuously increase with power, we feel it continuously fall with reducing torque. If we had a flat torque curve, and no frictional/aero losses, we would accelerate at a constant rate. Yet by your logic, we would accelerate at an ever increasing rate, since as speed increases, revs and therefore power increases. That's obviously incorrect.

Your "0.00001mph per bang" statement just shows how you have misunderstood Force, Work Done (force over a distance) and Power (work over time). Those extra bangs aren't accelerating you faster, those extra bangs are moving you faster.

If I could post some graphs you would see exactly what I'm saying and why it is correct.

Dave

Message Thread:

bhp or torque by 'KJM' (17 Aug 2009 @ 17:31)

Re: bhp or torque by 'davidmc' (17 Aug 2009 @ 17:46)

Re: bhp or torque by 'PaulMRotax' (17 Aug 2009 @ 18:30)

Re: bhp or torque by 'davidmc' (17 Aug 2009 @ 19:20)

Re: bhp or torque by 'QuickOldTimer' (17 Aug 2009 @ 19:20)

Re: bhp or torque by 'davidmc' (17 Aug 2009 @ 19:22)

Re: bhp or torque by 'KJM' (17 Aug 2009 @ 19:38)

Re: bhp or torque by 'QuickOldTimer' (17 Aug 2009 @ 22:44)

Re: bhp or torque by 'davidmc' (18 Aug 2009 @ 0:14)

Re: bhp or torque by 'QuickOldTimer' (18 Aug 2009 @ 9:49)

Re: bhp or torque by 'davidmc' (18 Aug 2009 @ 13:05)

Re: bhp or torque by 'QuickOldTimer' (18 Aug 2009 @ 13:51)

Re: bhp or torque by 'davidmc' (18 Aug 2009 @ 15:10)

Re: bhp or torque by 'QuickOldTimer' (18 Aug 2009 @ 15:43)

Re: bhp or torque by 'davidmc' (18 Aug 2009 @ 23:41)

Re: bhp or torque by 'QuickOldTimer' (18 Aug 2009 @ 23:57)

No ! , the original qustion was... by 'Chads' (19 Aug 2009 @ 0:58)

Re: No ! , the original qustion was... by 'QuickOldTimer' (19 Aug 2009 @ 1:11)

Re: No ! , the original qustion was... by 'davidmc' (19 Aug 2009 @ 8:36)

Re: No ! , the original qustion was... by 'QuickOldTimer' (19 Aug 2009 @ 11:31)

Re: No ! , the original qustion was... by 'davidmc' << You are here!

Re: No ! , the original qustion was... by 'Hi99' (19 Aug 2009 @ 19:15)

Re: No ! , the original qustion was... by 'TanglerTKM' (19 Aug 2009 @ 22:48)

contd by 'TanglerTKM' (19 Aug 2009 @ 22:51)

Re: contd by 'davidmc' (19 Aug 2009 @ 23:57)

Re: No ! , the original qustion was... by 'davidmc' (19 Aug 2009 @ 23:40)

Re: No ! , the original qustion was... by 'Hi99' (20 Aug 2009 @ 20:13)

Davidmc is this correct? by 'Hufggfg' (21 Aug 2009 @ 8:33)

Re: Davidmc is this correct? by 'davidmc' (21 Aug 2009 @ 9:57)

Re: Davidmc is this correct? by 'Hufggfg' (21 Aug 2009 @ 12:02)

Re: Davidmc is this correct? by 'davidmc' (21 Aug 2009 @ 13:07)

KJM, your best means of altering .. by 'Chads' (18 Aug 2009 @ 2:13)

Re: KJM, your best means of altering .. by 'KJM' (19 Aug 2009 @ 9:39)

David, that doesn't make sense by 'Booney' (19 Aug 2009 @ 23:19)

Re: David, that doesn't make sense by 'davidmc' (19 Aug 2009 @ 23:53)

Maximum accel is at max torque by 'PhilOwen' (20 Aug 2009 @ 17:28)

Re: Maximum accel is at max torque by 'QuickOldTimer' (20 Aug 2009 @ 20:59)

Re: QOT by 'John' (20 Aug 2009 @ 22:18)

Re: QOT by 'QuickOldTimer' (20 Aug 2009 @ 22:26)

Re: QOT by 'John' (20 Aug 2009 @ 23:51)

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