Motor RPM

[thetrainkid]

I am planning to kitbuild an 04 shunter chassis to fit the Dapol plastic kit, and have settled on the High Level option.

However how do I choose a motor and gear ratio to match the slow speed of these shunters? I am relatively new to the hobby and under 15 so I am not prepared to scratchbuild any gearsets or anything like that.

[thetrainkid]

I may need a chart for this (like how much rpm will need how large a ratio).

[Barclay]

Hi have a look at the High Level Kits website - there's a whole section on the size and ratio of their gearboxes to help choose the right one. They are furloughed right now due to scarcity of component parts but worth the wait!

 

Ratio wise a diesel shunter should be nice and slow - 40:1 is good enough for the slowest of motors such as the square 6 pole Minebea that is obtainable from China via ebay but for most model motors 80:1 or even more will give good results. Having said that the High Level 03/04 chassis kit comes with a gearbox, 108:1, so you just need to get a motor and Chris will help you with that as well.

[ikcdab]

Going slightly off topic, I have always been intrigued by the Dapol 04 kit. I've never bought one. How good is it and how does it compare to more modern offerings? 

Having asked the question, what I am sure about is that all the Dapol kits give an excellent and cost effective start in the hobby.

[DCB]

I have Airfix and Dapol 04 Kits and the Airfix is superior in all respects, the Dapol moulds must be tired by now as the Airfix mouldings are much crisper and are black so can be left unpainted.  The Dapol is grey so needs painting..  Some of the kits just aren't "Square," the old Airfix Pug ften as distorted rear cab sheets which make te cab lop sided but the 04s seems pretty much ok

The Bachmann body is a much better starting point.    I used 60 to 1 gears on my Wrenn 08 shunter on a Ring Field motor and it sounds ready to explode at a scale 30.   That is a very solid rigid chassis. I woudn't recommend less than 40 to 1 on a lightly built chassis and woud use a two stage for more than 40 to 1 where rigidity s suspect.     These  204 hp shunters have a low tpp speed around 28mph, but a narrow rev range and a 5 (?) speed gearbox so they were not that great at slow running, you don't often see them at walking speed, a quck trot is more likely light engne, loaded the torque converter allowed them to move really slowly, or not at all if overloaded with the engine bellowing.  Off topic but  That needs a really decent  DCC sound system to replicate and I don't know of anything avaiabe commercially that can achieve this. 

[thetrainkid]

On 27/04/2021 at 08:56, ikcdab said:

Going slightly off topic, I have always been intrigued by the Dapol 04 kit. I've never bought one. How good is it and how does it compare to more modern offerings? 

Having asked the question, what I am sure about is that all the Dapol kits give an excellent and cost effective start in the hobby.

I have one and it was simple to put together with Tamiya Extra Thin. I am only 12 so that shows you how easy it was!

Transfers come included for the late BR crest and nos D 2300  and D 2277

[ikcdab]

1 hour ago, thetrainkid said:

I have one and it was simple to put together with Tamiya Extra Thin. I am only 12 so that shows you how easy it was!

Transfers come included for the late BR crest and nos D 2300  and D 2277

Thats really helpful, thanks!

[thetrainkid]

How do you fit a flywheel to a motor and what does it do?

[Barclay]

A flywheel adds to the mass of the moving parts of a motor, so it softens the motor's response to control inputs, and allows a small amount of 'run-on' when the power is shut off. This can help the loco to run over dead spots, but it also helps to replicate the feeling of mass and momentum that real loco's have and our small models don't have much of. In practice it can make a loco feel smoother to drive. 

 

Some say they don't notice an effect, especially with smaller flywheels, but I still think they are worth fitting. 

 

To fit a flywheel, you first need the room in the loco body, and a motor with a shaft at both ends. then the flywheel bore has to match the motor shaft diameter but that's OK as most are either 1.5mm or 2mm. It may not push on easily and need easing slightly with a drill bit or reamer. Otherwise push it onto the motor shaft at the opposite end to the gearbox and secure with Loctite or superglue - very little and applied from the rear making sure it doesn't get close to the motor bearing. A flywheel does add load to the motor's bearings so push it as far down the shaft as possible i.e. close to the motor, leaving just enough room to reach the bearing for oiling purposes.

[thetrainkid]

On 04/05/2021 at 14:51, Barclay said:

A flywheel adds to the mass of the moving parts of a motor, so it softens the motor's response to control inputs, and allows a small amount of 'run-on' when the power is shut off. This can help the loco to run over dead spots, but it also helps to replicate the feeling of mass and momentum that real loco's have and our small models don't have much of. In practice it can make a loco feel smoother to drive. 

 

Some say they don't notice an effect, especially with smaller flywheels, but I still think they are worth fitting. 

 

To fit a flywheel, you first need the room in the loco body, and a motor with a shaft at both ends. then the flywheel bore has to match the motor shaft diameter but that's OK as most are either 1.5mm or 2mm. It may not push on easily and need easing slightly with a drill bit or reamer. Otherwise push it onto the motor shaft at the opposite end to the gearbox and secure with Loctite or superglue - very little and applied from the rear making sure it doesn't get close to the motor bearing. A flywheel does add load to the motor's bearings so push it as far down the shaft as possible i.e. close to the motor, leaving just enough room to reach the bearing for oiling purposes.

 Saw it here

 

[thetrainkid]

Also does anyone have suggestions for good motors? Branchlines market Mashima ones but they seem really expensive compared to not long ago.

[Barclay]

15 hours ago, thetrainkid said:

Also does anyone have suggestions for good motors? Branchlines market Mashima ones but they seem really expensive compared to not long ago.

Since Mr. Mashima passed away his motors are now at a premium, especially since there is no obvious successor.

 

High Level supply small motors both conventional and coreless. I have tried one of their iron cored ones and it seems to work well. Really only suitable for smaller prototypes. The Mitsumi M15N is a decent cheap motor of about Mashima 12/20 size that runs quite slowly and is available very cheaply direct from China via ebay. You do sometimes have to remove an existing gear from the shaft and there is talk of fakes. Cambridge Custom transfers sell genuine ones for about £7. The mounting holes are diagonal so if you want the motor to sit level you have to re-drill your gearbox or just solder it on. Otherwise search ebay for 12v dc miniature motors and see what there is - I have tried Minebea 15mm square 6 pole rotor motors, again very cheap. 2mm shaft, very slow revving and very strong. I also have some other faster revving ones with no brand name but a 5 pole skew wound armature. Mike Edge appears to have used the same one and found it OK. It's not as easy as it used to be....

[Quarryscapes]

More info and datasheet for Mitsumi here https://shop.coastlinemodels.co.uk/product/mitsumimotor/

 

There are indeed fakes out there, with a stupidly high start voltage and zero controllability, quite unsuited to model locomotive use but fine for constant RPM scenic stuff. I have a couple I bought for comparison purposes with the real deal. I can supply the real thing with or without worm from stock. 

[bécasse]

When he reopens tell Chris Gibbon at High Level what you want the motor and gearbox for and he will be able to suggest the optimum combination. It is probably best to ring him. Note that he does a chassis kit for the 03 which can also be used for the 04, but you don't, of course, have to take that option.

[thetrainkid]

1 hour ago, Quarryscapes said:

More info and datasheet for Mitsumi here https://shop.coastlinemodels.co.uk/product/mitsumimotor/

 

There are indeed fakes out there, with a stupidly high start voltage and zero controllability, quite unsuited to model locomotive use but fine for constant RPM scenic stuff. I have a couple I bought for comparison purposes with the real deal. I can supply the real thing with or without worm from stock. 

Saw your profile. I'm modelling Wales too! Although I am unsure whether the 04s made it to North Wales...