Model Boat Mayhem

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: Motor  (Read 4433 times)

Gopher

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 98
  • Location: Mansfield, Notts
Motor
« on: November 26, 2012, 02:11:23 PM »

Hello all, can anyone tell me if the motor out of a Bosch 12v cordless drill will power a 42inch tug?
Logged

Tug-Kenny

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 7,671
  • Location: Newport. S Wales
Re: Motor
« Reply #1 on: November 26, 2012, 02:35:28 PM »


Try a torque test.  That is to say,  try gripping the shaft whilst it's turning.  (safely of course and without the gears).

You could also measure the amps taken during this sort of test.    :}

Ken

Logged
Despite the high cost of living   .......... It remains popular

Gopher

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 98
  • Location: Mansfield, Notts
Re: Motor
« Reply #2 on: November 26, 2012, 03:31:38 PM »

No chance of holding the shaft, how do I test the amp bit
 
Logged

Tug-Kenny

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 7,671
  • Location: Newport. S Wales
Re: Motor
« Reply #3 on: November 26, 2012, 03:39:44 PM »


Have you removed the motor from the frame ?   so that it's by it's self on the bench.The amp meter goes between one of the battery leads and the wire to one of the terminals on the motor.


Ken

Logged
Despite the high cost of living   .......... It remains popular

Gopher

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 98
  • Location: Mansfield, Notts
Re: Motor
« Reply #4 on: November 26, 2012, 03:51:32 PM »

I think I've done it, it went between 1.57 and  2.35 if I have done it right
Logged

Tug-Kenny

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 7,671
  • Location: Newport. S Wales
Re: Motor
« Reply #5 on: November 26, 2012, 04:25:48 PM »


That would be normal.  All you need to do is find a prop with a diameter Less than the diameter of the motor cage.

Let us know how you get on

ken
 
Logged
Despite the high cost of living   .......... It remains popular

Gopher

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 98
  • Location: Mansfield, Notts
Re: Motor
« Reply #6 on: November 26, 2012, 04:55:30 PM »

That might cause me a problem then because the prop I was going to use is the one on the tug which is a 4 blade brass that is 60mm in diameter the motor is 40mm, the motor that is in the tug at the moment has a diameter less than the prop and I thought that the motor just wasn't strong enough, so my thought was if I put a 12v drill motor in it would have the power needed, my other tug which is the same size has an MFA Marlin in and runs really well with a 3 blade prop, but the Marlin is a lot bigger than the Bosch motor.
Logged

Shipmate60

  • Global Moderator
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,320
  • You bark - I will bite!!!
  • Location: Fareham
Re: Motor
« Reply #7 on: November 26, 2012, 05:23:53 PM »

Most drill motors are quite high revving.
The torque is supplied by the gearbox.
A 2:1 or 3:1 reduction would power the model well.

Bob
Logged
Officially a GOG.

Gopher

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 98
  • Location: Mansfield, Notts
Re: Motor
« Reply #8 on: November 26, 2012, 05:55:46 PM »

Sorry about this, being new to the hobby, do you mean I would have to put a gearbox on it to make it run right?
Logged

Shipmate60

  • Global Moderator
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,320
  • You bark - I will bite!!!
  • Location: Fareham
Re: Motor
« Reply #9 on: November 26, 2012, 05:59:19 PM »

The motor should have a gearbox fitted.
If it runs about 4000 oish should be fine on that prop.
The MFA Marlin runs about 9000 rpm on 12 volts.

Bob
Logged
Officially a GOG.

Gopher

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 98
  • Location: Mansfield, Notts
Re: Motor
« Reply #10 on: November 26, 2012, 08:00:09 PM »

Put a couple of photos on, can't see a gearbox on the motor, so I assume it must be in the chuck assembly, if so any idea how I get it out?
Logged

Tug-Kenny

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 7,671
  • Location: Newport. S Wales
Re: Motor
« Reply #11 on: November 26, 2012, 08:11:22 PM »


The gears will reduce the speed too much for your use.  In all honesty you would be better off getting a 900 type motor from ebay. They are what I use for Tugs and the prices can be quite reasonable.

Ken

Logged
Despite the high cost of living   .......... It remains popular

Gopher

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 98
  • Location: Mansfield, Notts
Re: Motor
« Reply #12 on: November 26, 2012, 08:21:46 PM »

Thanks, what do I type in,  just tried  "900 rc motor" and it only found one at 83.99
Logged

tugnut

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 403
  • Location: herne bay kent
Re: Motor
« Reply #13 on: November 26, 2012, 08:50:51 PM »

HI Gopher i use the car fan motor in my tugs you can get them cheap on ebay.
 
regards John b
Logged

Stavros

  • Guest
Logged

tugnut

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 403
  • Location: herne bay kent
Re: Motor
« Reply #15 on: November 26, 2012, 08:59:24 PM »

Thats a good find Dave and a good price :-))
Logged

Tug-Kenny

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 7,671
  • Location: Newport. S Wales
Re: Motor
« Reply #16 on: November 26, 2012, 09:16:04 PM »


That's the ones I meant.  (didn't want to give them free adverts).  I've got two ready for the next project.

Go for it Gopher.     :-))

ken

Logged
Despite the high cost of living   .......... It remains popular

WasWatchleader

  • Shipmate
  • *
  • Offline Offline
  • Posts: 5
  • Finally got back!!!
  • Location: Newport. Wales
Re: Motor
« Reply #17 on: November 27, 2012, 02:19:58 PM »

That would be normal.  All you need to do is find a prop with a diameter Less than the diameter of the motor cage.

Let us know how you get on

ken
That is an interesting concept Ken.  :-))
Where did you discover that?   Can you tell us the rationale for it?  :-))
Logged

mikgo

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 74
  • Location: Derbyshire
Re: Motor
« Reply #18 on: November 27, 2012, 03:47:06 PM »

Hi
I use a T24 motor from Mobile Marine Models. It has Hi torque and low revs and low current drain so should meet your needs. The model that I have fitted it in is a 46 inch Anchor Handling Tug with a 60mm prop.
Logged
if we didnt have boats, we'ved  have webbed feet

Tug-Kenny

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 7,671
  • Location: Newport. S Wales
Re: Motor
« Reply #19 on: November 27, 2012, 03:58:13 PM »

That is an interesting concept Ken.  :-))
Where did you discover that?   Can you tell us the rationale for it?  :-))


I believe it's related to "Load arm length" calculations.  The larger the diameter, the more force is needed to overcome it's turning resistance. Water, being heavier than air, has more frictional resistance, so the larger the diameter of the propeller the more force is needed to turn it around.

The only way to  exceed these rules is to decrease the width of blade as the length increases and to increase the speed of rotation.  This, of course, is undesirable in a tug as it's 'low down grunt' that will be required. More blades can be introduced as the power to weight ratio will be within the boundaries of the motor's diameter and the amount of coils within it's magnetic ring.

Or as Mikgo says, your going to need torque so a good choice of motor is essential for the job in hand.

Hope this helps

ken


 
Logged
Despite the high cost of living   .......... It remains popular

Gopher

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 98
  • Location: Mansfield, Notts
Re: Motor
« Reply #20 on: November 27, 2012, 07:52:23 PM »

Thank you all for you comments, I have scrapped the Bosch motor idea, in favour of the auction site one I'm not to concerned about the cordless idea I only paid a quid for the drill and 2 batteries,
Logged

Tug-Kenny

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 7,671
  • Location: Newport. S Wales
Re: Motor
« Reply #21 on: November 27, 2012, 08:21:48 PM »


Plenty of power there. Mine runs on two and the Captain can go surfing in the wash on acceleration.    {-)


ken

Logged
Despite the high cost of living   .......... It remains popular

Norseman

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,484
  • Location: Huyton, Liverpool
Re: Motor
« Reply #22 on: November 27, 2012, 09:26:07 PM »

Yes I have bought them from the same seller and I was 100% happy with the transaction. So you can certainly buy with confidence.

Dave
Logged
Pages: [1]   Go Up