Hello!
I want to make a ball launcher with wheels, the wheels will spin fast and the ball will passs through them and fly.
Which motors should I use? I want to reach speed of 64 km/h.
Thanks for the help!
Which motors should I use?
Gasoline powered motors.
What size balls? What do they weigh? What does "fast" mean? Check out ANY motor catalog. The speed shown is NOT really slow, slow, medium, fast, super fast, and good god almighty that's wicked fast.
But if you find GGATWF motors, buy 2.
Do some math. Diameter of the launch tire * rpm will give you tread speed.
Give yourself some wiggle room and buy motors that have a little more.
Edit: I assume you will be monitoring the rpm to know when the wheels have reached launch velocity.
I assume you will be using or creating motor drivers so that you can control the motor speed.
You might read up about PID, a common method to control motor systems.
You do not specify the ball type. But it’s weight might make a difference in the launch speed.
Something about the ratio of the ball weight and the weight of the wheels.
But if the ball weight is low, you might just ignore this.
And there will be some loss due to the energy needed to squeeze the ball as it passes through the wheels.
But you can also ignore that if you simply spin up the wheels to a known speed and launch a ball, measuring the launch speed. To low? Set you target motor speed higher and try again.
I have some GGATWF motors for sale. Salvaged them from some "WTF is this" equipment!
So the basic physics is: motors spin up the wheels, the wheel kinetic energy is used
to accelerate the ball, and this slows down the wheels, then the motor spins them
back upto speed before the next ball.
The basic power requrements are the energy to spin the wheels back up to
launch speed divided by the time between lauches, plus or course the power
to overcome friction and air resistance.
This may mean a fairly low powered motor is enough if you are prepared to wait
between launches, but you'll still need decent bearings on the wheels to handle the
kick-back on launch (or some shock-absorbing).
You can calculate the change in momentum on launch and translate that to a change
of angular momentum on the wheel, and then calculate the wheel rotational energy
change - all basic mechanics calculations.
You need to provide the mass of the ball, not just its velocity. What sort of total size
do you envisage? How often between launches? What start-up delay is allowed?
hi!
There is no problem to wait between launches.
I need to know how many RPM for a motor I need.
thanks for the help
I need to know how many RPM for a motor I need.
Simply look at the motor specs in any catalog. Choose one who's maximum RPM rating is stated as "enough".
The motor is NOT launching a ball. The motor is driving some mechanism that is launching the balls. Only YOU have any idea what size balls, how heavy the balls are, or what the launching mechanism looks like. Only YOU can determine how fast the mechanism needs to be driven.