cricket bowling machine / baseball ?

[mikhailfaradayski]

I am trying to build my own bowling machine for cricket as the ones on the market are ridiculously expensive
.

Sorry, i don't wish to be rude, but when you wrote this, i thought you had some notional idea of how you were going to set about this and had a basic idea already. I hadn't realised you woke up this morning and thought you'd get someone else to design it from the ground up.

If you come forward with a few suggestions or basic concept ideas, maybe people here will be able to 'assist' you.

 

[DrGonzo]

The main mechanism of the machine consists of two heavy wheels, between 30 and 50 cm in diameter, shod with solid or pneumatic rubber tyres, each driven by its own electric motor.

What sort of RPM would I need to get a ball going at up to 70mph?

What's the relationship between the circumference of a circle and its diameter?

3.14...why ?
Yes, in theiry I could get the revs from that but wheels spinning at 80mph will not fire out a ball at 80mph due to squeezing the ball, resistance, inefficiencies, etc.

 

[DrGonzo]

I am trying to build my own bowling machine for cricket as the ones on the market are ridiculously expensive
.

Sorry, i don't wish to be rude, but when you wrote this, i thought you had some notional idea of how you were going to set about this and had a basic idea already. I hadn't realised you woke up this morning and thought you'd get someone else to design it from the ground up.

If you come forward with a few suggestions or basic concept ideas, maybe people here will be able to 'assist' you.

I'm not trying to get someone else to design it but I know very little about motors. It doesn't mean I can't learn but at the very least I need to know a guide on what RPM to have and because it'd going to be inefficient at first design, it's going to need to spin a lot faster than the professional machines in the market at present.

I know the rough height to pitch it from, the wheel diameter and some spacing apart to allow the balls to pass through but not how to modify a starter motor to run constantly.

I've got to start somewhere before drawing dome rough plans
eg I saw some transit starter motors on ebay...

 

[mikhailfaradayski]

The main mechanism of the machine consists of two heavy wheels, between 30 and 50 cm in diameter, shod with solid or pneumatic rubber tyres, each driven by its own electric motor.

What sort of RPM would I need to get a ball going at up to 70mph?

What's the relationship between the circumference of a circle and its diameter?

3.14...why ?
Yes, in theiry I could get the revs from that but wheels spinning at 80mph will not fire out a ball at 80mph due to squeezing the ball, resistance, inefficiencies, etc.

Are you sure thats true? If a car wheel rotates with a peripheral speed of 70mph, the car will travel at 70mph, unless the wheel is slipping, generally undesired whilst travelling in said car.

As BAS has asked whether you know the relationship between dia and circ of a circle, assuming no losses in the system, can you give the required rpm to produce a peripheral speed assuming drive wheel diameter of 100mm?

 

[ban-all-sheds]

3.14...why ?
Yes, in theiry I could get the revs from that but wheels spinning at 80mph will not fire out a ball at 80mph due to squeezing the ball, resistance, inefficiencies, etc.

Well - it's the best I can come up with.

Do check, BTW, that the tyres on the wheels you use are at least N or P rated - wheelbarrows don't usually travel at 80-odd mph, (unless this guy is pushing them....

)

 

[ban-all-sheds]

Oh - and check if your insurance will pay out if your contraption hurts anyone.

 

[DrGonzo]

Are you sure thats true? If a car wheel rotates with a peripheral speed of 70mph, the car will travel at 70mph, unless the wheel is slipping, generally undesired whilst travelling in said car.

As BAS has asked whether you know the relationship between dia and circ of a circle, assuming no losses in the system, can you give the required rpm to produce a peripheral speed assuming drive wheel diameter of 100mm?

Yeah, but what I meant was as the ball passes through, it is squeezed a little bit between the rubber. This extra force will actually slow the wheels down such that wheel travelling at 70mph will only throw the ball out at maybe 30 or something like that. I'm not really sure there's anyway to know that apart from trial and error.

 

[ban-all-sheds]

Better get a good supply of motors in if you're expecting to work them so hard that they'll halve in speed....

 

[mikhailfaradayski]

Are you sure about that?

I think a cricket ball will prove to give far less resitance to the motor's motion than, say, an engine will!

Are you able to answer the last question? If not, then there is not much point to carrying on with this.

 

[thomo27]

Any idea if this will work:
http://www.ehow.com/how_2383328_build-pitching-machine.html[/QUOTE]
Presumably it will work, if you do it right.

But it will work as a baseball pitching machine, not a cricket bowling machine. Apart from a round ball the two are completely different - the balls are different sizes and weights, cricket balls have a raised seam, baseballs do not, but the biggest difference, as well you know, is in the speed range, distance and trajectory, line, length etc of the balls, to say nothing of where, when, how, why and by how much the balls move.

It's probably a lot of work to build this thing; it may well be interesting, and you may end up with a machine which throws balls at you, but it won't be a bowling machine, and anyone who uses it hoping to improve their cricket batting will be sadly disappointed.

Ive seen so many full tosses/hip high deliveries/buffet bowling deliveries 'call it what you like' get wickets that I think there would be players out there at ameteur level who wouldnt mind facing a spell of this type of bowling however if you manage to pull it off and can recreate all types of bowling then it will be a top effort..

Good Luck

 

[DrGonzo]

Better get a good supply of motors in if you're expecting to work them so hard that they'll halve in speed....

Ok, so thoughts on 2 transit starter motors?
eg
Introducing a ball will slow the motor down a bit, I was just going on what I had read here:


Then I can have a play..."safely"...with them and see what's possible.

[circumference (in ft)] X RPM X [60 min per Hr] / [5280 ft per mile]

Better get a good supply of motors in if you're expecting to work them so hard that they'll halve in speed....

Ok, so thoughts on 2 transit starter motors?
eg http://cgi.ebay.co.uk/NEW-FORD-TRAN...s_SM?hash=item4834bae0dd&_trksid=p3286.c0.m14
Introducing a ball will slow the motor down a bit, I was just going on what I had read that a reduction of about 15% is normal when it first grips the ball and throws.

Then I can have a play..."safely"...with them and see what's possible.

[circumference (in ft)] X RPM X [60 min per Hr] / [5280 ft per mile]

 

[DrGonzo]

Are you sure about that?

I think a cricket ball will prove to give far less resitance to the motor's motion than, say, an engine will!

Are you able to answer the last question? If not, then there is not much point to carrying on with this.

If you build your own hoover or cupboard, are you covered for any damages it causes you?

 

[mikhailfaradayski]

Can you give the answer to this question?
By all means, describe the formula, but can you tell me the answer?

What is the required rpm to give a peripheral speed of 70MPH assuming there are no frictional losses in the system?

The drive wheel diameter is 100mm

 

[mikhailfaradayski]

Are you sure about that?

I think a cricket ball will prove to give far less resitance to the motor's motion than, say, an engine will!

Are you able to answer the last question? If not, then there is not much point to carrying on with this.

If you build your own hoover or cupboard, are you covered for any damages it causes you?

I'm not sure why you are asking me this question?

 

[DrGonzo]

Can you give the answer to this question?
By all means, describe the formula, but can you tell me the answer?

What is the required rpm to give a peripheral speed of 70MPH assuming there are no frictional losses in the system?

The drive wheel diameter is 100mm

Assuming 1:1 gearing.
70mph = 112kmh
112kmh = 112000metres/h = 1866.66metres/min
Circumference = 0.1m
RPM = 18,666RPM

Are you sure about that?

I think a cricket ball will prove to give far less resitance to the motor's motion than, say, an engine will!

Are you able to answer the last question? If not, then there is not much point to carrying on with this.

If you build your own hoover or cupboard, are you covered for any damages it causes you?

I'm not sure why you are asking me this question?

I thought that's what you wanted me to answer!