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TTools V2.0

A simply web-software which calculate some usefull data

Tuesday 30 March 2010, by Nico71

Today, I will present my first software : TTools V2.0.


This web-software allows you to calculate some usefull data which are :

  • -Linear speed (max and in charge)
  • -Torque (in charge and max)
  • -Mechanical power (on motor, on wheels)
  • -Electrical power
  • -Lost power (mechanical and electrical)
  • -Efficiency (motors and drivetrain)
  • -General efficiency of the vehicule
  • -Autonomy (normal use and in charge)
  • -Usefull angles (approach, departure and clearance)

Instructions For Use

To calculate this data, it’s very simple :

  • -Choose your motor(s) and the number of motor(s)
  • -Choose your battery (9V or 7V) and capacity
  • -Choose your gears
  • -Enter dimensions of your vehicule (wheels base, wheels diameter...)
  • -Press "Calculate the data"

It’s a web-software, then just click and try ! -TTools V2.0

About TTools V2.0 - Calculation

  • Linear Speed : functions of type of motors, battery , gear reductions and wheel diameter.
  • Torque : functions of type of motors, number and gear reductions.
  • Electrical power : functions of type of motor(s) and number.
  • Mechanical power : functions of type of motors, number and drivetrain
  • Efficiency of drivetrain : functions of gears (worm, knob, spur, bevel)
  • General efficiency : functions of motor(s) and drivetrain efficiency.
  • Lost mechanical power : functions of drivetrain : Worm screw and Knob gears reduce the efficiency. The software detects worm gears, knob gears and spur gears automaticaly.
  • Clearing Abilities : functions of dimensions of your vehicule. It’s based on trigonometrical functions.

Normally, the software doesn’t bug if you try absurd values. By the way, if you have bugs, please leave a comment to inform me. Also, this software is under development so if you need other usefull calculated data, please ask me ;)

Note regarding the climbing abilities : At the moment, it’s too complicate to calculate the climbing abilities angle, causes lot of complicated values (wheel, grip, weight distribution, type of constructions, bearing systems friction and roll friction).

Forum posts

  • I think we need one more dimension for center high point, because most trucks are higher in center than by axles. Also ability to put more toothgears one after another would be nice to calculate efficiency of the driveline.

    Other than that, good job!

  • It’s a pretty good software!

    To the mechanical part I have to admit, that as I could measure and experience it, LEGO gears and the whole driveshaft is very inefficient. I think, it’s impossible, to achieve such high efficiency rates as in real life, even with spur gears. IMO efficiency changes at high forces (torques), which causes varying efficiencies from gearing to gearing. So you can rather only estimate the overall efficiency.
    For estimating "back" the driveshaft efficiency, e.g. you can calculate the wheel torque by measuring the force, which the truck can pull (on smooth surface, to avoid stalling). Knowing the RPM, you can calculate the "motor power" from RPM-Ncm function (P = 2PI*f*M, of course all in SI), knowing the wheel RPM and torque you can count the "wheel power". If you divide the 2 powers, you get the (almost) real efficiency. Its much worse :(.

    About the motors:
    The mechanical power, that Philo gave at the given RPM-s, are sg like an avarage power, it hardly can be a constant... The calculated diagrams are made according to Philo’s diagrams (about 1,5 year ago), but they are inaccurate. Note, that according to Philo, RC motors give 3,925W (on it’s outer output, at 9V) at 500RPM!
    (P= 2*3,14*500/60*0,075=3,925)

    Moreover, I have measured these characteristics as well, and they are a bit different from Philo’s (partly could be, because I measured the motor reaction force (=>torque)). In the summer I will make more measurements, then post you.

    Some other: You might add lubrication, and an average "bearing" factor, which also influences efficiency;)

    To sum it up, there are more inaccurate things here, but its much more than nothing;) So keep up the good work!

    • I admit that the efficiency depends of torque and speed but It’s quite difficult to have a right model. A good aproximation per example will be with the theory of Hertz contacts of Hookes Theory (with finite element modelling). But my software is very simple. I can’t introduce this type of theory with theory.

      For the RPM, calculation is made with value in charge, mesuring by me. And I mesure the same speeds as philo.

      I am waiting for your result and your detailled operating experiment.

      My software is quite simple, I admit, but It’s very difficult to have a complex model in javascript (like ANSYS). Spite of, I search to improve my software. I think that many value still accurate.

      Thanks for your comment ;)

  • Hi, soon I will release a new version, with a new feature : maximun climbing angle. I hope the result will be good. It’s based on a perfect model with total wheel grip. I have considered the torque on wheel, the weight (despite it’s only concentrated in center of gravity), angle and mechanical power. I have solved this in statics, dynamics and energetics. The result is accurate but the power on wheel isn’t really accurate. So I would like to introduce the HUN_Lac’s experiment method, to calculate the efficiency and mechanical power with a weight pulling method.

    Stay tunned !

  • Hi,

    when i click the link to the TTools i get this message:

    "ERREUR 404 - Document non trouvé"

    Is it possible to put it online again? Or send it to my email address.

    View online :