Need advice for motor selection for a Vosper MTB build

[Daniel Cardona 1Participant @danielcardona1]

Hello To all

I'm new to this new hobby, not the first in RC tough as usually i fly Rc model Aircrafts. anyway, i'm interested to start building a Vosper MTB from a Glynn Guest plans 1/32 scale. I'm new to Electric's so i need advice for the motor selection.

on the old construction feature in the magazine, the suggested motor are in the brushed direct drive series from 400-500 size. i was thinking to use a graupner speed 500 and took a look in this website

http://www.cornwallmodelboats.co.uk/acatalog/standard_motors.html

i choose this because i need a supplier that is able to ship to Malta, i could find a speed 500 but there is a Graupner speed 600, but would that be too much?

any suggestions pls

Kind regards

Daniel

[Daniel Cardona 1Participant @danielcardona1]

[ashley needhamParticipant @ashleyneedham69188]

Daniel. There are 500`s and 600`s and not all are created equal. The graupner speed 500 motor in nothing special, and there are loads of 600s so it would depend on what you buy. A Graupner speed 600E ECO is not a ferocious motor and I have used them to upgrade a bit from a "normal" cooking 500 and would go ok in your boat.

As you are paying shipping and possibly expensive import tax, a slightly more powerful motor might be a good choice, as it will guarantee a reasonable performance…nothing worse than paying out all that money and being disappointed with a weedy 500.

Another avenue, and this is frowned upon generally as the motors are obviously unknown quantites, is using motors from broken electric drills and so on. These are usually about the 500 size, and you may find one locally that goes ok at a fraction of the cost of importing one??? Screw fixing holes are likely to be about the same so installing and then swapping if reqd would be quite easy. Trying the motor straight across the battery with an ammeter or watt-meter (in the boat, in the water and with a prop on!) would show you instantly whether the motor was just too juicy or worth a try. This option would depend on how expensive it is to ship to Malta.

Also, a brushless motor might be worth considering, Kv matching the sort of revs a 500 would acheive, with the battery you would be using. If reverse is not an issue, aircraft speed controllers are cheap but will need a bit of ventilation through the boat, easy enough to arrange..open hatches/doors and so on. Do you get your aircraft stuff locally or is everything imported?

Just as a suggestion.

Ashley

[Daniel Cardona 1Participant @danielcardona1]

Hello Ashley

Thanks for the reply, yes most of my stuff that I buy for my aircraft are imported, small stuff expecially are reasonable priced including shipping.

As for the motor maybe I should have a try on the 600 then, i,m worried about the rpm aswell. What max rpm should i have to have some good ?speed on the water. Mind you, I dont want a speed demon but a nice scale speed. Maybe a bit to have in reserve.

Regarding speed controler, what should I look for?

Damn, I’m such a noob at this

Regards
Daniel

[Dave MilbournParticipant @davemilbourn48782]

**LINK**

Daniel

I would recommend using the installation shown for Shamrock (the top diagram) in conjunction with the 540/1 motor, a P80 speed controller and a P95/1 fuse board. On 7.2v the model would be fine on something around a 35mm 3-blade scale prop. There's plenty of scope to increase the speed if required by upping the voltage. Component Shop will ship to Malta. Graupner motors are getting very rare these days. I have three new 600 ECOs and a 720 Torque which I wouldn't sell for any money!

Dave M

Edited By Dave Milbourn on 26/05/2014 15:43:28

[John W EParticipant @johnwe]

Hi ya there Daniel nice to see you on this forum as well. Ive just dug out the motor box from the original build I did on Mayhem – the motor is an old one from Graupner – a JUMBO 550 max voltage 9 volt and free running speed of 13,500 rpm. That would be on 9 volt. I used to run it on a 7.2 battery driving a 30 mm 2 blade plastic racing plop. The speed controller in it, I believe, is an MTroniks 15 amp. This will no doubt make Mr Milbourn's toes curl hearing of MTroniks cos he is an ACTion man

aye

John

[Daniel Cardona 1Participant @danielcardona1]

Thanks dave for the reply.

I didn’t know about the component shop, it has a nice selection of motors and stuff, speed controllers are expensive tough. Can I just use a simple speed controller? And if I use 2.4ghz do I need to use a suppresed motor?

Regards
Daniel

[Daniel Cardona 1Participant @danielcardona1]

Hi john

Nice to see you here too, correct if i’m wrong but on your build thread of the vosper mtb you mentioned that the motor had to at least have 17000 rpm, should u at least aim at 15000rpm?

Regards
Daniel

[John W EParticipant @johnwe]

hi ya Daniel, when I quoted the rpm I was honestly under the impression that I had originally fitted a Graupner speed 500 in the model which is rated at 17,600 rpm on 7.2 volt – it wasnt until I was having an eyeball at the model I built that I realised I had put the old Graupner motor in it. So what I will need to do now is go into the loft again and take some more pics.

if I were you, I would try and aim for 15,000 rpm,

Aye

John

[John W EParticipant @johnwe]

Edited By bluebird on 26/05/2014 18:53:31

[Daniel Cardona 1Participant @danielcardona1]

Hi john

Thanks for posting photos of your model, it keeps me motivated. The speed controller shown in the second pic came ready with that fuse or you added by your self? If I use 2.4ghz radio, still I need to supress the motor?

Regards
Daniel

[John W EParticipant @johnwe]

Hi ya Daniel

The speed controller shown didnt come with the fuse fitted. I fitted an auto blade type fuse and holder to it. You can purchase these from Component Shop or Ebay and if you are running a 2.4 radio there is no real reason to surpress the motor – as 2.4 isnt prone to electrical interference from the motor. As a safeguard though, I always do surpress the motors – just in case in the future I swap the radio back to 40 mghz.

aye

John

[John W EParticipant @johnwe]

Daniel, if you have a look in my album there are a couple more photographs of her under the heading Boats.

John

[Daniel Cardona 1Participant @danielcardona1]

Posted by bluebird on 26/05/2014 19:18:44:

Hi ya Daniel

The speed controller shown didnt come with the fuse fitted. I fitted an auto blade type fuse and holder to it. You can purchase these from Component Shop or Ebay and if you are running a 2.4 radio there is no real reason to surpress the motor – as 2.4 isnt prone to electrical interference from the motor. As a safeguard though, I always do surpress the motors – just in case in the future I swap the radio back to 40 mghz.

aye

John

Hi john

sorry for all the questions, hope i don't bother you. but you there's a need of a fuse with the speed controller? some other safety precaution?

regarding the photo's yes i already watched them in your album. still prefer the close ups

kind regards

Daniel

[Malcolm FraryParticipant @malcolmfrary95515]

Supressing a motor is never a bad idea. Interference does not just get into the system through the radio aerial, it can be picked up by other wiring. Also, if you are not sailing alone, you might be causing interference to others nearby.

A fuse between the battery and speed control guards against the chance of a fault in the speed control turning your boat into a flaming wreck. While the ESC might well have over current protection, it cannot protect itself against internal faults which can happen.

[Daniel Cardona 1Participant @danielcardona1]

Posted by bluebird on 26/05/2014 19:19:16:

Daniel, if you have a look in my album there are a couple more photographs of her under the heading Boats.

John

HI john

what size of rudder did you used on the MTB

regards

Daniel

[John W EParticipant @johnwe]

hi ya Daniel

if you check your personal messages on Mayhem you will find I have sent you a link where I got the rudder from. It gives yee the sizes of rudder on that link.

aye

john

[Daniel Cardona 1Participant @danielcardona1]

Posted by bluebird on 28/05/2014 14:02:29:

hi ya Daniel

if you check your personal messages on Mayhem you will find I have sent you a link where I got the rudder from. It gives yee the sizes of rudder on that link.

aye

john

Thanks john , your the Man!. I've just finished to cut the templates and ordered some parts , the motor will be a torpedo 500 form sussex model centre, and the 9inch shaft is already ordered from ebay, including the coupling. when i have these in hand hopefully i can start to cut some balsa.

kind

regards

Daniel

[John W EParticipant @johnwe]

Hi ya Daniel whilst reading through your last PM, i noticed you asked about the weight – should you increase it for using in the sea – I wouldnt ncrease the weight of the hull it does perform well in rough water.

heres a thing now though, when you actually begin to build it why dont you put it on this forum so we can have a look and see – you will find its quite easy to download pics on this website you just create an album and download the pics from your album to the build

you dont have to worry about resizing the pics or anything like that like you do on certain websites the other bonus point about putting the build on this forum is that other people will read it and you may come across one or two problems which you can air on this forum.

and others may come up with another alternative answer than what I would give and you may find it will suit you down to the ground and it may be easier for you. When you have finished this build and if you like this style of build of semi scale – have a look at what else Glynn Guest has done – he has done some nice models – Also have a look at the Swordsman that Dave Milbourn drew – the build for that is on Mayhem which I myself made a few years back – another lovely model to build and sail. This particular model has travelled a few times with me on holiday as its a model which is easy packed up and sails well anywhere.

Ived built many a scale warship come other types of model which I enjoy doing but I really love doing these semi scale ones as there seems to be an extra bonus and zing from them.

aye

john

[Daniel Cardona 1Participant @danielcardona1]

Hi John

yes posting picture in this website crossed my mind, i wish to do it actually but right now so far i'm ready only from the templates. unfortunately i can't work that fast as i used to be with any project, since we got bigger in our family.

model boats always interested me since i was with rc aircraft, and i really want to have a go on something different, and have that thrill to accomplish something an see it working. still waiting for the parts and i really need to have the motor, shaft and rudder, so i can prepare for any alterations needed. so finger crossed and hope that i have enough spare time to start cutting balsa…Oh..the old balsa bashing!..happy days!

thanks john again for your patience to answer my questions.

Kind regards

Daniel

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