JasonP
09-23-01, 09:46 PM
<p align="center"><font size="4"><b><font face="Verdana, Arial, Helvetica, sans-serif">Torque
and Acceleration - <a href="mailto:james.f.reynolds@vander bilt.edu">Jim
Reynolds</a></font></b></font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2">I will try
to explain this as simple as possible. Torque is the measurement of a
given amount of force applied at a given distance in a radial vector.
We measure the output energy (torque) of an engine in foot*pounds from
either the crankshaft or rear tire. From the tire we typically have a
drivetrain loss to incorporate, but on a goped with a direct drive system
it is marginal. An automatic transmission can have a parasitic drag of
up to 20% of the car's engines output!</font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2"><br>
Acceleration can be DIRECTLY derived from torque mathematically because
we can calculate the time element. Acceleration is the 2nd derivative
of time. Think about the one acceleration that EVERYONE has memorized,
gravity. 9.8m/s/s you can find out the velocity of an object that was
falling by taking the integral of it's acceleration and then<br>
calculating in the other variables. Likewise, from that you can take the
integral again and find out how high it fell from and what speed it started
at when it began to fall. The point of all this is to show that acceleration
is directly related to time which is an integral part of power which is
related to torque!</font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2">Power is
simply energy transfered divided by time.</font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2">If you know
the power output of an engine and the work that it has to do, (such as
move you and your goped a given distance) you can<br>
calculate the amount of time it will take you to do that, and calculate
acceleration!</font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2">1 hp = 550ft*lbs/sec.
= 746 Watts (joules/sec) Everything is related! </font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2"><br>
If you wanted to calculate the different top speeds and acceleration rates
of your goped with different gearing sizes this is what you would do.</font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2">1. Put your
goped on a dynamometer and get the torque curve<br>
- the torque curve is the graph of output on the y-axis and rpm on the
x-axis</font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2">2. Now that
you know the power bands of the goped engine you can calculate it's horsepower
from the gearing and torque. An interesting thing to notice is that ALL
engines does not matter what kind will always have their torque and horsepower
curve intersect at 5,250 rpms. </font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2">3. To find
your best acceleration plot your horsepower graph using the different
gearing combos that you would like to use and calculate the area under
of the torque curve between the given rpms that you would like the best
acceleration. That's all there is to it, lol.</font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2">Calculating
top speed is a little more difficult, I will go into that later if enough
people are interested, but I am blabbering enough about all this ****.
Let me know what you guys think.</font></p>
and Acceleration - <a href="mailto:james.f.reynolds@vander bilt.edu">Jim
Reynolds</a></font></b></font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2">I will try
to explain this as simple as possible. Torque is the measurement of a
given amount of force applied at a given distance in a radial vector.
We measure the output energy (torque) of an engine in foot*pounds from
either the crankshaft or rear tire. From the tire we typically have a
drivetrain loss to incorporate, but on a goped with a direct drive system
it is marginal. An automatic transmission can have a parasitic drag of
up to 20% of the car's engines output!</font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2"><br>
Acceleration can be DIRECTLY derived from torque mathematically because
we can calculate the time element. Acceleration is the 2nd derivative
of time. Think about the one acceleration that EVERYONE has memorized,
gravity. 9.8m/s/s you can find out the velocity of an object that was
falling by taking the integral of it's acceleration and then<br>
calculating in the other variables. Likewise, from that you can take the
integral again and find out how high it fell from and what speed it started
at when it began to fall. The point of all this is to show that acceleration
is directly related to time which is an integral part of power which is
related to torque!</font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2">Power is
simply energy transfered divided by time.</font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2">If you know
the power output of an engine and the work that it has to do, (such as
move you and your goped a given distance) you can<br>
calculate the amount of time it will take you to do that, and calculate
acceleration!</font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2">1 hp = 550ft*lbs/sec.
= 746 Watts (joules/sec) Everything is related! </font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2"><br>
If you wanted to calculate the different top speeds and acceleration rates
of your goped with different gearing sizes this is what you would do.</font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2">1. Put your
goped on a dynamometer and get the torque curve<br>
- the torque curve is the graph of output on the y-axis and rpm on the
x-axis</font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2">2. Now that
you know the power bands of the goped engine you can calculate it's horsepower
from the gearing and torque. An interesting thing to notice is that ALL
engines does not matter what kind will always have their torque and horsepower
curve intersect at 5,250 rpms. </font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2">3. To find
your best acceleration plot your horsepower graph using the different
gearing combos that you would like to use and calculate the area under
of the torque curve between the given rpms that you would like the best
acceleration. That's all there is to it, lol.</font></p>
<p><font face="Verdana, Arial, Helvetica, sans-serif" size="2">Calculating
top speed is a little more difficult, I will go into that later if enough
people are interested, but I am blabbering enough about all this ****.
Let me know what you guys think.</font></p>