Locomotive drives

[damienjohnson]

hi,

 

I am just in the middle of designing a new kit GWR Dukedog in N gauge and 2mm.

 

 

 

Now this particular model will be tender driven, front wheels and rear wheels of the tender driven by the gearbox motor combi, the center wheels will be floating.

 

i am wondering what people prefer, engine drive or tender drive?

 

also i am looking at creating a standard set of gearboxes to suit various motors, is this a good idea?

 

all feedback is appreciated

GWR Dukedog Tender.pdf

[Kris]

I would rather have the motor in the tender but driving the wheels in the loco to prevent the lock up of the loco wheels as it is travelling along.

[damienjohnson]

but if your loco wheels is made correctly then they should not lock up, plus you can make the chassis and test it without having a motor fitted.

 

there are some n gauge loco's on the market with tender drives.

 

more weight can be added in the tender to help with traction.

[2mm Andy]

damienjohnson, on 16 Jan 2013 - 17:30, said:

 

also i am looking at creating a standard set of gearboxes to suit various motors, is this a good idea?

 

all feedback is appreciated

 

Provided they're well-designed and flexible enough to suit a range of locos, etc. (and useable for split frame chassis locos) I can't see why they wouldn't be a good idea. Are you thinking of something similar to the gearbox Missy Julia has designed and posted details of on her blog (and which is installed in the Peckett she is currently building)?

 

I prefer loco drive (with the motor in the tender if necessary). I'll be interested to see the design for the Dukedog tender - they're not very tall, so I'm assuming you're using a motor with a shaft each end and two gearboxes to drive the front/rear axles?

 

Andy

[damienjohnson]

Provided they're well-designed and flexible enough to suit a range of locos, etc. (and useable for split frame chassis locos) I can't see why they wouldn't be a good idea. Are you thinking of something similar to the gearbox Missy Julia has designed and posted details of on her blog (and which is installed in the Peckett she is currently building)?

 

I prefer loco drive (with the motor in the tender if necessary). I'll be interested to see the design for the Dukedog tender - they're not very tall, so I'm assuming you're using a motor with a shaft each end and two gearboxes to drive the front/rear axles?

 

Andy

its early days for the gearbox designs but yes i am hoping to make them as easy/common as possible.

 

the dukedog has a 10mm diameter motor fitted geared down on to a long shaft driving front and rear wheels, gearbox is 40:1, the height of the tender has been raised slightly to accomodate.

[richbrummitt]

Drive the loco and put a decent size motor in the coal space. There isn't a lot of space in these things and you will want some weight over the drivers to maximise traction.

[JohnBS]

I think that the tried and tested 2mm SA method of tender-mounted motor, wire cardan shaft drive through the firebox door and a gearbox in the firebox, powering the loco, is the best way forward. A self-contained powered tender just won't have enough space for adequate weight for traction (especially in the smaller 2,500 or 3,000 gallon tenders). I'm sure that you don't want to go down the route of traction tyres, as on most proprietary tender mechs.
If you have structural inside frames (split of course), the same chassis will do for any standard GWR tender, with appropriate cosmetic outside frames attached to the footplate and superstructure.
Motors can be anything you can get in, from 8mm Maxons to 12x19 Portescaps or Tenshodos.

Attached is a Bulldog so constructed, albeit with N-gauge wheels.
John

[damienjohnson]

one idea i have had is drive both tender and loco, its very possible with what i have come up with?

[damienjohnson]

here is the latest image of the chassis i have designed.

 

the motor is a 10/16 Faulhaber motor.

 

it fits right up to the top of the tender top which has been increased in scale height by 6".

 

the intermediate shaft can be extended to add a drive to the loco.

 

 

GWR Dukedog Tender Chassis 2.pdf

GWR Dukedog Tender Chassis 3.pdf

[2mm Andy]

one idea i have had is drive both tender and loco, its very possible with what i have come up with?

 

Why would you want to? If you're driving both loco and tender from the same motor, matching the speed of the loco drive and tender drive is going to be very tricky. You'd have to select gearbox ratios that would give the same track speed to both the large loco wheels and the smaller tender wheels. If you get it wrong, one of the two will be fighting against the other constantly.

 

I can't honestly recall seeing a loco that has featured such an arrangement. That's not to say it's not a good idea, but perhaps you should experiment and report back with your findings.

 

Andy

[damienjohnson]

It should be fairly simple to work out as the wheels are a metric size and using metric module gears allowing me to select the correct gear to match the tender drive.

 

I will finish the tender design first as I have done.

 

It can then be an option to kit builders of how they would like to drive the model

[-missy-]

I am finding it VERY hard to not think you are using my ideas and trying to make money from them. First the wheels using 3D printed centers and now a range of gearboxes. I know you have been interested in them because you have been sending me emails asking for more information.

 

I have no problem with people using them for their own use but trying to make money from them? Really?

 

Not happy

 

M

[damienjohnson]

Missy,

 

I'm not using your ideas. They have already been done in all scales, the wheels I had produced for oxford expo 2010 in white metal, 3d printing then was not fine enough, plus my wheels have square holes and I have produced square drive shafts. Gear boxes are used in all scales, my kit designs allow different gears using the same holes to have alternative ratio's, nothing is new its just not been done on a commercial size in this scale. I'm sure the association if they had more money/time and desire would have done things along this route.

 

I hope you are not too disappointed!

[queensquare]

. I'm sure the association if they had more money/time and desire would have done things along this route.

 

 

I'm sure they wouldn't. The accepted 2mm Association methods, as outlined by JBS and his beautiful Bulldog, have been developed over many years as the best way of doing things in this small scale by many highly skilled and talented modellers.

Yet again you  seem determined not to listen to others. A small powered tender will be lucky to pull itself along let alone push a loco and pull a train without traction tyres which are not feasible in 2FS and best avoided in N if possible. Making the tender too tall to try and get more weight in is a backward step and powering the loco and tender is just bonkers - and won't work.

I will be looking to Julia and others in the Association for ideas and innovation. I had great hopes when you first appeared on the scene, particularly as you were promising Midland prototypes but I haven't as yet had the the confidence in any of your products to shell out the cash and give one a try.

I'm sorry if this sounds harsh Damien but, having looked at the latest update on your website, its cuckoo land. You are promising to do all sorts of Kits already covered by the Association, Fencehouses and the RTR manufacturers  - Gresley pacifics, a Schools, NE Q, GWR prairie 2-8-0 (?) etc.

 

Jerry

[2mm Andy]

Damien,

 

Your comments on Julia's external blog here do seem to suggest that her influence was perhaps a little stronger than you suggest.

 

http://modelopolis.blogspot.co.uk/2012/06/3d-printed-wheels-first-attempt.html?showComment=1340695570840

 

(and square-ended axles (not "drive shafts", please!) are not a new idea - Slaters have used them on their 7mm loco driving wheel range for many years)

 

Anyway, I do think that we need to calm things down a bit, otherwise this thread will end-up being locked by the moderators.

 

Andy

[Horsetan]

Intellectual property experts may well take an (academic) interest.....

 

There is no property in an idea, but there is in its expression and the resultant work.

[damienjohnson]

Morning people,

 

Well i do take onboard critisism and i have taken onboard lots of advice since i came on the scene in 2010.

 

Firstly in 2010 i was spoken to in great length from the association chairman at time discussing pre quartered and back to back wheels, but at that time technology was not sufficient to achieve what we have today.  I had tried casting wheel centers and i tried etched centers both of which Julia (missy) commented on in 2011! i have thanked missy for offering me the information of who made her wheels (my quote 'I like your wheels who did them for you? Im still in the design stage of my pre quartered wheels and these may be an easier/better option.') and i then have designed my own prototypes from original locomotive drawings from the national archives, i have not copied her design i have just used the same manufacturing technique.

 

At Warley in 2012 again long conversations were had with association members reference what i had done and many people were very impressed.

 

The reasons why i have done things different to the association is to offer change and to make things easier and offer more variety!

 

You could say we are all copying ideas from the larger scales.

 

Jerry,

 

im sorry you feel this way about my kits, my sales so far would suggest otherwise.  in the early days there were a few design issues which again following advice from many were overcome. 

 

My range of kits has come about from market research from the many people in both 2mm and n gauge worlds saying this is what they would like.

 

There is nothing wrong with making kits already out there, others did it, PECO/farish, Hornby/Bachman!!

 

As for the drive systems, the whole reason for starting this thread, i have been asked by a n gauge customer to produce kits for his business with tender drive.  I asked the question what people prefer so i can offer this kit in various options, again very easy to do.  Why not drive all wheels, it can be done again very easily, surely driving 5 pairs of wheels on a loco & tender is better than driving just 2 pairs of wheels in the loco?!

 

My kits are designed as accurately as possible in size and scale,

 

Jerry, your comment that i dont listen is a strange one when regarding a 'small powered tender' suprises me as you suggested i used maxon/faulahaber motors when we chatted at Oxford 2010 & Warley 2012, hence the design of the kit will allow the fitment of a 10mm diameter motor, which does even allow space for mashima as well.

 

I'm sure this topic has raised many questions/answers and thankyou all for the input, i will continue to engineer what i am doing with advice that people offer.

[2mm Andy]

As for the drive systems, the whole reason for starting this thread, i have been asked by a n gauge customer to produce kits for his business with tender drive.  I asked the question what people prefer so i can offer this kit in various options, again very easy to do.  Why not drive all wheels, it can be done again very easily, surely driving 5 pairs of wheels on a loco & tender is better than driving just 2 pairs of wheels in the loco?!

 

Not necessarily, for the reasons I stated in my earlier reply. If you're designing a 4-4-0 tender loco, I'd be equally concerned about weight distribution and pick-up (assuming you're doing 3D printed wheels for it) as well as transmitting power to the wheels. If you have the 2mm magazine back-number dvd, it's worth reading Nigel Ashton's article on the building of his Dukedog.

 

As regards the Dukedog tender, is there any reason why you're not using an 8mm dia. motor? Surely this would mean that you don't have to increase the height of the tender sides by 1mm (which is a pretty big compromise in 2mm scale!) but retain the longitudinal layshaft drive to front and rear axles.

 

I'll be interested to see how your planned range of kits develops - as Jerry has commented in more general terms, designing yet another 8F kit when there are 2 existing 2mm kits (and an N gauge model, albeit not up to current standards) seems somewhat nonsensical when there are plenty of other fantastic loco designs to choose from.

 

I admire your desire the challenge the norms, but there are often very good reasons why 2mm product development has gone the way it has.

 

One thing I would say is that it would be nice to see a gallery on your website to showcase the models built from your kits by others. Obviously it needs people to send photos to you, but it's something used to great effect by other kit manufacturers in the various scales.

 

Andy

[queensquare]

Jerry,

 

im sorry you feel this way about my kits, my sales so far would suggest otherwise.  in the early days there were a few design issues which again following advice from many were overcome. 

 

My range of kits has come about from market research from the many people in both 2mm and n gauge worlds saying this is what they would like.

 

There is nothing wrong with making kits already out there, others did it, PECO/farish, Hornby/Bachman!!

 

As for the drive systems, the whole reason for starting this thread, i have been asked by a n gauge customer to produce kits for his business with tender drive.  I asked the question what people prefer so i can offer this kit in various options, again very easy to do.  Why not drive all wheels, it can be done again very easily, surely driving 5 pairs of wheels on a loco & tender is better than driving just 2 pairs of wheels in the loco?!

 

My kits are designed as accurately as possible in size and scale,

 

Jerry, your comment that i dont listen is a strange one when regarding a 'small powered tender' suprises me as you suggested i used maxon/faulahaber motors when we chatted at Oxford 2010 & Warley 2012, hence the design of the kit will allow the fitment of a 10mm diameter motor, which does even allow space for mashima as well.

 

I'm sure this topic has raised many questions/answers and thankyou all for the input, i will continue to engineer what i am doing with advice that people offer.

 

Morning Damien,

 

thanks for your reply. Firstly, can I say I wish you every success and I'm glad sales are going well. I greatly welcome entrants in 2mm with your obvious drive and ability. That said I stand by my comments.

 

I did advise you to use Maxon/Faulhaber motors, the biggest you can fit in, not the 6mm you originally used. I wouldn't advise increasing the size of the tender by 6 scale inches to get a 10mm one in.

 

Driving all wheels of loco and tender simply won't work - if it was easy it would have been done before.

 

Loco drive is the way forward in my opinion, either with the motor in the loco if room or in the tender driving the loco via a shaft. Bachmann did experiment with tender drives on some locos but had problems (skidding drivers, lack of adhesion etc) and have now reverted to loco drive.

 

I'm surprised your market research has led you to the conclusion you need to duplicate a lot of what is already available but its your money supporting the R&D so best of luck.

 

As I said to you at Warley, self quartered wheels are not a priority. Quartering wheels is not difficult once shown how to do it - as those at the loco building workshop Julia and I mentored at discovered. What is crucial is that wheels are strong and accurate, I'm not convinced FUD printed wheels provide this yet. Julia, who is leading the way with these experiments, has had problems and continues to try new approaches and techniques. She has the good sense to realise that whilst this new technology has great potential for the perennial problem of wheels in 2FS, we are not there yet. I do however think that in the long run printed wheel centres will provide the answer.

I am going to build one of her Peckett kits using the FUD wheels and I'll be interested in how the wheels perform.

 

Jerry 

[rope runner]

Drive the loco and put a decent size motor in the coal space. There isn't a lot of space in these things and you will want some weight over the drivers to maximise traction.

 

This is definitely the right way forward...

 

Also, any compromise in tender height will mean you won't sell. Accuracy is clearly key in 2mmFS

 

With regards to any question of "ideas" regarding gearboxes, a quick glance at the 4mm market (which really has seen it all) tells you what will work and what won't, and from what I've seen it's all pretty "standard" design wise.

 

Just my 2 cents

 

Paul A.

[Chris Higgs]

but if your loco wheels is made correctly then they should not lock up, plus you can make the chassis and test it without having a motor fitted.

 

there are some n gauge loco's on the market with tender drives.

 

more weight can be added in the tender to help with traction.

 

There are locos on the market with tender drive, but they don't pull enough, even with traction tyres. I played around a lot with a Farish Jubilee tender when we were trying to produce replacement wheels. Without traction tyres it could hardly move itself and the loco (which had a fair bit of friction), and even with tyres was nowhere near what a Jubilee should be able to handle. It was a lot of fiddle to adjust.

 

Fleischmann locos are another question. German tenders have a lot of space for weight (and gear trains), and so they run very well, but again only with lots of traction tyres. And you still get the issue of the loco wheels jamming up once they pick up the slightest bit of dirt.

 

Unless you are going to fill it with Plutonium, there is no way a small GWR tender has enough room for weight.

 

I honestly think you will get a lot of grief going down this road. Loco drive for me.

 

Chris

[Chris Higgs]

here is the latest image of the chassis i have designed.

 

the motor is a 10/16 Faulhaber motor.

 

it fits right up to the top of the tender top which has been increased in scale height by 6".

 

the intermediate shaft can be extended to add a drive to the loco.

 

Surely you can get a 10mm motor into the design without increasing the size of the tender sides, but placing the motor in the coal space of the tender, so the only thing needed is an (over) generous load of coal.

 

Chris

[Chris Higgs]

I'm surprised your market research has led you to the conclusion you need to duplicate a lot of what is already available but its your money supporting the R&D so best of luck.

 

Personally, I think that the list of kits proposed is so long that we will never see most of them happen. And even if we do, we will have no time to build them all.

 

Chris

[Pixie]

Hi Damien,

 

Interesting thread and I'm certainly one for experimentation outside of the accepted guidelines. For something like joint loco and tender drive, the maths behind it is relatively simple but I would be worried about the real world constraints that such a model would bring along - differing frictions, etc, etc. I think it would be worthwhile building a prototype to get the plan sorted out and highlight the limitations and pracitcalities of building the idea. If it works - ace, bring it on. If it doesn't - it was a good learning exercise.

 

From a kit design perspective, I think a big can motor in the tender would be my preference (larger the better) to give plenty of power with drive via a universal joint to the driving wheels. I'm unsure of the costings, but the option of a whitemetal boiler would be great or perhaps 3D printed with a designed void for lead weighting. The weight dristribution would need to be looked at to try and get the weight over the driving wheels, rather than the front pony truck.

 

Please, please, please do not compromise accuracy for features though. The Hornby 4mm diesels with their flappy doors and opening vents and the Peco Collect Goods with the iffy tender are good exampels of this!

 

From a punter point of view, and I don't mean this as a personal dig, the list of your promised products is gigantic and does make me wonder how much will actually happen and when. My skepticism is derived from the droves of suppliers who've promised the world and delivered very little - to your credit you at least have several kits under your belt.

 

Cheers,

 

Pix

[Chris Higgs]

My range of kits has come about from market research from the many people in both 2mm and n gauge worlds saying this is what they would like.

 

From quite a bit of experience selling coach kits what people say they would like and what they actually put their hands in their pockets for are not the same thing. In fact, the answer to the question would you like 'xxx' is almost always yes. I always follow it with, 'give me a cheque as a deposit then'.