Where's the Rate of Acceleration gauge?

[MeltDownZ]

Seriously, I would love one.  I'm not aware of any that are available so I'm thinking of getting one developed.  Just testing the waters, would anyone here be interested?  Here's my thoughts on the specs:

- Digital speedo converted to rate of acceleration.
- Realtime readout of acceleration rate.
- Resettable memory would store highest value.
- House in a nifty display like the gear indicators are.
- Obviously, I hope, this is an add-on to the stock bike and not a replacement for the traditional speedo

If anyone is unfamiliar with Rate of Acceleration, it means how fast your bike is picking up speed - or the Pull.  

If you accelerated 0-100mph in 20secs, your average rate of acceleration is 5mph/sec.  

If you did it in 10 seconds, your average ROA would be 10mph/sec

If you did it in 5 seconds, your average ROA would be 20mph/sec

You can see by this how benefitial it would be to know ROA for kicks or for tweaking your drag racing skills.  Also for measuring a bikes performance capabilities.  Torque is a great number to know.  But, factor in weight, tires, etc., it doesn't mean as much compared to knowing How fast can it go? (ROA)

Last part... while you may average 7mph/sec on a run, it would be cool to know you pulled 12mph/sec for a moment.



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[Revlis]

Can you mod A G-tec to accurately measure bike performance??? Would be a pretty good answer, thoug hI do not think it includes a Rate of Accel.. Would be a cool figure to have displayed.

 

[Charlesbusa]

They couldn't design a acceleration guage that could withstand the Busa!!!!

 

[denver_red]

Hi Everyone,

I own an '04 LE and this is my first post (pictures will follow). However, I have been hanging around this site since September and decided to let my 20 years' experience as a mechanical engineer lend a hand.

Here are a few tidbits about classical physics (without the effects of aerodynamic drag).

X = distance
V = velocity or speed (distance divided by time) in ft/sec or miles/hr
A = acceleration or the rate of change in velocity in ft/s^2

Here are some equations:

V = X / T
A = Vo* T + (1/2 * A * T^2)

I'll use the Grudge Match article in the August edition of Motorcyclist magazine (which shows 1/4 mile race times between a Busa and a zx12r) to help us out with computing acceleration numbers.

One problem with acceleration is it can change moment by moment. Therefore, one normally speaks of average acceleration values. For example, does one expect the 0-60 feet acceleration numbers to be the same as the 0-1320 feet numbers in the quarter mile? Not likely on a Busa.

From the article, the 0-60 feet times were in the low 1.7 second times, and the best 1320 feet time was 9.471 seconds.

What were the average accelerations?

First on the 1/4 Mile

X = 1320 feet
T = 9.471 sec
Vo * T = 0, starting from dead stop so initial velocity is zero

Rearranging equation #2, yields

X = 1/2 AT^2, or A = 2X / T^2
A = (2 * 1320) / 9.471 * 9.471 = 29.43 ft/s^2

Acceleration is also talked about in "g's". On earth 1 g is equal to about 32.2 ft/S^2 (this is how fast a body falls toward the ground in feet per second per second).

So in the quarter mile, the Busa had an average acceleration of about 0.91 g's.

Now let's look at the 0-60 feet acceleration numbers:

0-60 ft
T = 1.7 seconds
X = 60 feet
Vo * T = 0 because we are starting at a dead stop

solving for A

A = 2 * 60 / 1.7^2 = 41.52 ft/S^2 (or about 1.3 g's)

Therefore, this information states that the Busa's average acceleration slows as it went down the track.

So if one understands this math, what would be the 1/4 mile elapsed time for the Busa if it could keep the 0-60 feet acceleration number?

Accelerometers are gauges that measure acceleration. The point to note, is what is the smallest increment it can compute as an "average."


Hope this helps.

 

[MeltDownZ]

denver_red,

Thanks for the input. My thoughts are this... give me G's or mph/sec averaged over a 1 second time frame. A graph of an entire run would be great, but, showing 1sec interval averages would work just fine for most of us.

 

[MeltDownZ]

denver_red,

I don't understand the math... you do. And, you've built up my curiosity. So, as the owner of this thread, I am giving you the responsibility of telling us how fast (mph) would he go in the 1/4 mile and how many sec's would it take if the busa could keep up the 1.3G's?

Thanks!

 

[denver_red]

MeltDownZ,

Here we go...

X = VoT + (1/2 A T^2)

again VoT is zero, so we are left with

X = 1/2AT^2

In this case we know X and we know A, so we solve for T


T^2 = 2 X / A
T = Square Root (2 X / A) = SQ (2 * 1320 / 1.3 * 32.2)
T = 7.94 sec (with constant acceleration)


The velocity component gets hosed because it is not constant during the 1/4 mile run (it used to be at zero). If velocity were a constant then the value at the trap would be:

A = V / T or V = A * T

Then,

Velocity = 1.3 * 32.2 ft/sec * 7.94 sec = 332 ft/sec

now convert into miles per hour

226 miles per hour NOT LIKELY!

 

[BigBSBusa]

Thanks, Denver Red for including the G numbers. When I read the title of the thread that is what came to mind more than the acceleration gauge. Probably too much flying experience (or lack thereof in recent years) that makes me enjoy those numbers, especially the negative Gs. That will make your heart flutter!

 

[MeltDownZ]

denver_red,

Thanks for crunchin' the numbers!

 

[techbum]

Rate of Acceleration gauge?.........and I always thought that was the seat of your pants.....