Model Boat Mayhem
Mess Deck: General Section => Beginners start here...! => Topic started by: David Boreham on September 23, 2019, 06:28:22 pm
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i am sorry if it is becoming boring all the questions about the Milford Star! What engine would you use, believe it or not but Caldercraft don’t mention what engine to use in the instructions. On the plans they mention a mono perm or similar s/n! I am busy trawling the internet and web sites that sell the kit to see if there are any recommendations there! If anybody knows a blog with photographs as a guide to build, please add a link, I think I am going to need it!
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A monoperm is a 380 sized motor that runs on about 5000 rpm on 6 volts.
Bob
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This one will do you nicely on either 6v or 7.2v. https://www.componentshop.co.uk/385-dc-motor-mounting-bracket.html (https://www.componentshop.co.uk/385-dc-motor-mounting-bracket.html)
DaveM
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Thanks, I have just seen on Cornwall model boats site another engine but was waiting for your responses. They recommend or should I say people who bought the kit also bought MFA RE-540 1 3 pole Dc Motor Inc mount< only £8.93. What do you think, I will also need to buy a battery and electronic speed controller. Any recommendations really appreciated.
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I've used the 540 in 8 of my models and not had a problem with any of them so far. I use mtronics viper marine ESCs (either 15 or 20amp)and usually 6 or 12v sla batteries, although 2 of the models have 3300 nmh batteries for the speed increase. When I get around to building my M.Star the 540 will be my choice. I think it will be a little overpowered but that comes in handy to get out of the way of models whose owners aren't paying attention.
Regards,
Ray.
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Ray,
I was thinking along the same lines, the additional power will be useful as I will be sailing at my local yacht club, which is quite exposed and going against the wind may well need that additional umpf!
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Read up on the 540 motors. The specifications can differ hugely. You would probably be better off with a 5 pole low drain motor.
Colin
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Read up on the 540 motors. The specifications can differ hugely. You would probably be better off with a 5 pole low drain motor.
Colin
540 motors do have a huge range of variations, usually for faster and even faster applications. The one mentioned here was a 540/1, the /1 being very important. It indicates that the motor is wound differently to give torque at modest current rather than high revs at high current.
In past times, a 545* would have been a preferred choice, but these seem to be rare, the 540/1 has been recommended as a suitable replacement for the 5 pole motor.
Regarding monoperms, they came in a variey of forms as well.
There is a table showing them at:
https://www.modelboatmayhem.co.uk/forum/index.php/topic,11713.msg411055.html#msg411055
*NOTE: A 555, a totally different thing, mostly good as a paperweight as far as most boat modellers are concerned.
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389/385 sound a bit small to me for a model of around 3ft unless some form of gear reduction is used to amplify torque. What's the diameter and pitch of propeller on that model. The 540 motor sounds a better bet.
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Hi DB
The 540 rock crawler 80 turn motor is rated at 5500 rpm@ 7.2 volts and will easily turn up to a 3 blade 60mm prop.
Canabus
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FYI https://wheelspinmodels.co.uk/i/292786/ (https://wheelspinmodels.co.uk/i/292786/)
DM
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Nothing wrong with a 555. I have them fitted in my Mountfleet Puffer, Sterling American Scout and Mountfleet Osprey.
John
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Nothing wrong with a 555. I have them fitted in my Mountfleet Puffer, Sterling American Scout and Mountfleet Osprey.
John
Of course, I might have been thinking of the infamous 550 which was very much on offer on fleabay for a long time. :embarrassed:
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Malcom
You probably are. A Mabuchi 555 is a very nice motor for displacement vessels when run at 12v (approx 5500RPM and single amps). I think this is the one you remembered:
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Dave,
A couple of those fitted to a wheelie bin would make it live up to its name. :o
Plenty of room for the necessary LiPos inside too.
Colin
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Dave,
A couple of those fitted to a wheelie bin would make it live up to its name. :o
Plenty of room for the necessary LiPos inside too.
Colin
Nah - it'd melt a wheelie bin! 8)
DM
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Damn, I am more confused than ever, I thought I had made a decision and was destined for a 540 but now not so sure! I had hoped to start building on my next three days off from work, in which time Engine, battery and esc would have been bought and if not delivered, on their way.
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I understand your confusion, the whole motor labeling subject can be very confusing.
Based on the replies and my own experience, you were considering a 540 / 1 from the excellent Cornwall model boats, just get that one. As Malcolm said, it's a good torquey motor, great on 6 volts. I have used them and I'm very happy with the results. I agree there are other good options, but why get bogged down when you'd rather be building.
Chas
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in my 40" model 10" wide I started out with a 385 geared motor on 12V, that was too slow so I moved to the 385 without gears, that got hot on a 30mm prop, so i moved to a 540 motor, that works fine without getting hot on a 35mm prop (all the motors are the MFA ones) the 540 draws about 1.2 amps at no load (ie prop out of the water)
the 540 may be a bit on the overkill side, but gives me an extra nudge of power to get out of trouble.
https://www.mfacomodrills.com/pdfs/RE540-1.pdf
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I am currently working on an old time fishing trawler. I have also gone through the same problem.... Motors, prop size etc. I settled on a 540 motor with 80 turns, the prop is 3 bladed, 40 mm diameter with 7.2 volt battery. Because it is not a go fast boat, l went with a brushed motor.
The brushed motors are less money than brushless, BUT don't go cheap ! You get what you pay for..... Pride in your build is gone when it's powerless and drifting
I bought 3 of the 540's but each has different turn ratings ( l figured one would do the job ) the other 2 motors.... possibly future projects.
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Well I bought a 540/1 which was recommended by Howes models and Cornwall Model Boats which were very helpful. I am using a 6v battery. Speaking to my Father an 88 year old retired now model boat builder, he is suggesting I drill the prop shaft tube to weld a branch to it so that I can top up silica grease as the prob shaft may run hot. Any thoughts, I think my Dad is pushing my engineering/modelling skills to the extreme!
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Your father's advice is sound David. I think you would struggle to get the propshaft out for maintenance, the only way to do so would be to a. Remove the propeller, b. Remove the coupling and motor and, c. Pull the propshaft into the hull (IF there is sufficient access and clearance to do so).
You could of course uncouple the rudder shaft and bend the skeg to remove the rudder then you undo propshaft coupling and pull shaft out that way.
Caution : bending and straightening the skeg will weaken and ultimately snap it!
Best listen to your Father...
If your soldering/brazing skills aren't up to it, there are kits out there that attach oiling/greasing tubes directly to the prop tube - I'll see if I can find a link...
Regards,
Ray.
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Here's one link - there will be others available :-
https://www.modelboatbits.com/MobileDetail.php?Prod_ID=4601
Regards,
Ray.
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Ray,
Thank you, I will give it a go. You have to learn sometime. I just looked at the link though at that is a good clean way of doing it.
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You're certainly making better progress than I am, my Milford Star is still in its box in the loft!
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... and mine has made its way to the 'holding dock' (spare room) :embarrassed: and still boxed up!
Regards,
Ray.
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Ray,
Thanks for the link I have ordered an oiling tube from Model Boat Bits, do you know how long they take to deliver? I am itching to get on now I have started. At least I can start positioning the engine mounts rudder support etc. Once again thank you for the link.
Kind regards
David
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Hi David,
I'm not sure about the delivery times although it's probably a couple of working days.
A note of caution :-
When you drill the hole, use light pressure only, you don't want to be drilling straight out the other side.
Also, if you haven't already done so, you could make a building cradle for the hull while you're waiting for the delivery - keeps the hull nice and steady while you work on it.
Regards,
Ray.
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Ray,
I am currently using a cradle from another boat but it isn’t ideal. How do I get the profile, my Dad suggested using card and by cutting strips in the card use that to mould around the Hull, using that as a template. Unless anybody on here has a profile!
Regards
David
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How spooky is that, I just received an email they are processing my order!
I was talking to Stan last night, I am amazed at his builds and can only aspire to reach his quality. His wiring and layout is incredible. I wish he was a little closer, I would make myself a real pest!
Good tip on drilling the prop shaft, I have a bench and a Dremel now so will take it slowly.
Regards
David
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Soft soldering with a large iron to get the solder flowing. Then drill out the spur.
Bob
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I am currently using a cradle from another boat but it isn’t ideal. How do I get the profile
I use a hard plastic profile gauge, bought at B&Q a few years ago, although I have used other methods such as soft wire coat hanger or those 'twisters' that are sometimes used to hang things from hooks.
Whatever you use, be careful not to press too hard, otherwise you will get a distorted result.
Once you have the profile it is then transferred onto card (I use card from cereal box) and use this as a template, test fit and once happy with the result transfer to your chosen medium - plywood for instance.
Hope this helps.
Regards,
Ray.
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Ray,
It does, I have just bought MDF but have now realised it isn’t waterproof! Basic error.
Regards
David
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If you go ahead with mdf make sure you wear a suitable mask - you don't want that in your lungs!
I seem to recall that there is a product for sealing mdf but can't remember what it was.
As for plywood, I think any thickness from 6mm up is good.
It is still advisable to wear a mask though, especially if you're working indoors.
Note: I hope I'm not 'teaching my granny to suck eggs' here. %)
Regards,
Ray.
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Ray,
Not at all, better warned. I think I may go and get some 6mm ply.
Regards
David
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A coat of resin or a couple of coats of varnish should seal up mdf well enough for this use.
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If you silver braze to grease tube onto the prop tube please be aware that the heat will distort the prop tube. been there and done it. Far better to use soft solder, it is a little more redeemable if it does not work out. I would gone with Steve at Model boat bits, grand lad and a good product, nemesis
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Nemesis,
I have ordered the oiling tube from model boat bits.
Ray,
I used the following method to create a template for my boat cradle.
I just need to cut it out from the ply wood.
[attachment deleted by admin]
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Good stuff David - now, when the stand is made you will need some sort of cushion to protect the hull.
I usually use old mouse mat strips, glued on in stages with cyano (super glue). I've also used draught excluder but that tends to come adrift after a while.
Regards,
Ray.
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On the matter of model cradles, I've had issues with most rubber/neoprene products after a while. Some of them mark the hull while one actually started to dissolve the paint! I now favour self-adhesive felt; this seems totally inert. If you need more padding then maybe apply the rubber/neoprene stuff and add a layer of felt on top.
Works for me.
Dave M
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Ray and David M, yes I had problems with draught excluder marking the Hull in the past as well. I was considering using some material as a damper.
Regards
David
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I agree with the idea of felt - I use 3mm thick felt and glue it to the wooden cradle with Bostik glue. It works great and does not mark the hull even after a few years. I think the piece if felt that I bought will last me a lifetime.
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Mark,
I agree, I am going the felt route.
Regards
David
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Hi David all looks good. Looking forward to some pictures.
Stan.
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HI David look at this for the Missouri fitting out.
Stan.
https://www.modelboatmayhem.co.uk/forum/index.php/topic,58769.0.html
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I am now looking at the prop shaft, it has a threaded end which I presume the prop mounts on and then an unthreaded end that goes into the universal joint. The prop shaft is 4mm in diameter, my universal joint coupling spindle is for 4mm. It fits on the threaded end but not the unthreaded end. So I guess I have to tap the end to make that also threaded? Help!
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It depends if your coupling is plain or threaded. You need an unthreaded (plain) coupling).
Most shaft inboard ends are unthreaded. The usual practice is to have an unthreaded coupling and perhaps also a collet to place between the couopling and the shaft tube.
Sounds like you need a new coupling.
Colin
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Colin,
I thought that might be the issue. At this rate I am going to end up with a draw full of bits!
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Like the rest of us!
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Al modellers have drawers full of bits but they usually come in useful sometime down the line. My drawers full of bits go back to the 1970s and often solve current problems. I have a whole box full of couplings!
Colin
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You will need to measure the motor spindle as well as the propshaft and order both of the brass inserts - I'm assuming the coupling is a Huco type - they're usually supplied with grub screws. Don't forget the Allen key, if you don't already have one.
I usually order my couplings from Cornwall model boats but there are plenty other suppliers out there.
Regards,
Ray.