Tender Powered 4-4-0

Kos
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Tender Powered 4-4-0

Postby Kos » Fri Nov 16, 2012 2:10 pm

Hi

Anyone successfully powered a 4-4-0 (6'6" drivers) from a tender mounted motor? Does the drive shaft go under the loco cab floor? What gearbox/drive did you use?

Many thanks, Stuart

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Tim V
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Re: Tender Powered 4-4-0

Postby Tim V » Fri Nov 16, 2012 3:52 pm

Not a 4-4-0, but a 2-6-0 and a 2-8-0. Smaller drivers than your example.

In both cases, the drive went under the footplate. The 2-6-0 had a 16mm can low mounted driving to a worm and wheel on the middle driver. The 2-8-0 had a Canon 1833 motor, through 1:1 spur gears to a gearbox on the third driver. The 18:33 could not be mounted between the wheels like the 16mm can. UJs came from Branchlines.

A 4-4-0 should be easy. Suggest you try various motor shapes and gearboxes over a plan of your loco.
Tim V
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Kos
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Re: Tender Powered 4-4-0

Postby Kos » Fri Nov 16, 2012 4:08 pm

Thanks, Tim.

Unfortunately, larger wheels need higher ratios (say 60:1) and hence bigger gears, lifting the output shaft. I've raised with Chris Gibbon the idea of a separate low ratio primary gearbox (maybe 20 or 30 to 1), coupled thru UJs to a 2 or 3 to 1 spur gearbox to lift the motor to a sensible height in the tender. Are the Branchlines UJs still available elsewhere?

I'm hoping that someone who has successfully powered a 4-4-0 will come forward. Maybe there's a simple solution out there somewhere?

Stuart

Philbax
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Re: Tender Powered 4-4-0

Postby Philbax » Fri Nov 16, 2012 4:19 pm

You could always turn the gearbox over so the drive shaft is underneath.
just a thought

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Tim V
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Re: Tender Powered 4-4-0

Postby Tim V » Fri Nov 16, 2012 4:24 pm

I am told (though have not seen it) that putting a box as you describe in the tender will result in the torque from the motor "flipping" the tender over.

I don't see why you can't use one of Chris's standard 60:1 boxes in your 4-4-0? They are designed to be used separate from the motor.
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Kos
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Re: Tender Powered 4-4-0

Postby Kos » Fri Nov 16, 2012 6:21 pm

That was my first thought, Tim - I've been using High Level gearboxes for some time now. I measured the axle/shaft spacing at 6mm on Chris's GearboxPlanner, which I thought would be a bit high. But looking again, I see I might reduce that by altering the angle of the two parts, though it is max 54:1. Isn't everything a compromise. I need to check with CG that it will work in this mode with the gearbox in front of the axle and the drive shaft going back over the axle. Thanks for ideas. :D

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Tim V
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Re: Tender Powered 4-4-0

Postby Tim V » Fri Nov 16, 2012 6:27 pm

His "Hump Shunter" goes up to 108:1 :!:
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Kos
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Re: Tender Powered 4-4-0

Postby Kos » Fri Nov 16, 2012 6:39 pm

True! But the output shaft is even higher.

I'm going to pursue the RRC+ with CG on Monday - I'm hoping it does the trick.

Unless someone out there in forum-world has the perfect solution?!?

Incidentally the loco is a Pickersgill 4-4-0. The Dunalastair IV I'm currently working on has a motor in the firebox (well, it was my first 4-4-0 ;) ) and it proved tricky to get weight over the drivers. My solution for that problem (after adding as much weight as I could) is to replace the tender chassis with one more amenable to transfering weight to the loco, i.e. twin beam at the rear not the front. The D IV tender chassis then goes under the Pickersgill motor-tender.

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jjnewitt
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Re: Tender Powered 4-4-0

Postby jjnewitt » Fri Nov 16, 2012 9:52 pm

Hi Kos,

I've constructed a few tender drives for steam locos including an LMS 4-6-0 with 6'9" drivers. This uses a 30:1 High Level Roadrunner+ gearbox with D1 drivestretcher and a Canon 1833 motor. Unless you are using a very high reving motor I wouldn't go above 60:1. Depending on the exact motor you may want a lower ratio of 54:1 or even 40:1. High Level have a speed calculator on their website which is useful. A 60:1 gearbox with a motor such as a Mashima 1420 will give a top speed of 63mph with 6'6" wheels. A 1428 will only give a top speed of 46mph so a lower ratio box would be better.

I always use High Level Roadrunner+ gearboxes in mine with a D1 drivestretcher. I haven't found an instance yet where I need a higher ratio than 40:1 but then I always use as big a motor as I can get in the tender, either a Canon 1833 or a Mashima 1630/1430. Once I'm satisfied with the hight of the input shaft into the gearbox I solder the drivestretcher to the gearbox. I certainly wouldn't include a reduction gearbox before the universal joint as the resulting increase in torque will play havoc with the drivetrain.

I always put the driveshaft through the firebox door rather than mess around trying to put it through the dragbox. I don't have any problems with the shaft being visable and it saves having to contrive a new coupling arrangement between loco and tender.

Good luck with the build.

Kos
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Re: Tender Powered 4-4-0

Postby Kos » Sun Nov 18, 2012 6:19 pm

Thanks for info Justin,

I've just made a Dunalastair IV 4-4-0 with a Mashima 1626/1426 and 54:1 RR+ on the rear axle and with the sides of the gearbox cut back to clear the backhead. With the smokebox and part of boiler full of lead, this is nose-heavy - not a problem in itself with Exactoscale sprung hornblocks on the bogie and twin beams on drivers. But the amount of lead I can get in the boiler above the motor limits its pulling power. Without the lead above the motor, it could just about pull the tender.

Before I go for a drive thru the firebox (I've just re-read that bit and it sounds quite surreal), I have been exporing options. Clearly a drive between cab floor and above footplate does bring its own problems. And I'm now aware of potential torque problems I hadn't thought about before.

After another chat with Chris G I may opt for a RR Compact+ tho I don't want to rush the decision.

p.s. what UJs do you use?

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jjnewitt
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Re: Tender Powered 4-4-0

Postby jjnewitt » Sun Nov 18, 2012 8:17 pm

I use Version 2 Ultrascale U/Js with 1/16" drive shaft. I'd post some pictures of the arrangement but I'm in the middle of moving house. My models and the hard drive containing what useful pictures I have are in a different place to the laptop and internet connection!

One of the big advantages of tender drives to me is the ability to achieve better weight distribution within the loco by filling the top of the firebox with lead. I'm sure that would be very helpful with tackling a 4-4-0.

Philbax
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Re: Tender Powered 4-4-0

Postby Philbax » Mon Nov 19, 2012 12:38 pm

Have a look at the exactoscale gearboxes, they are compact. I have used one in a Bradwell Auserity and the driveshaft from the tender is under the footplat


Phil

hollybeau
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Re: Tender Powered 4-4-0

Postby hollybeau » Thu Nov 22, 2012 8:58 pm

I am currently building a Kirtley 0-6-0 tender loco (OK not a 4-4-0 but some of what follows may be relevant). In many ways it is quite normal fare - Comet sprung chassis (made for the 4F but the axle spacing is correct) and Gibson wheels (but my favourite brass-centred ones with the crankin bosses cut out as this is an outside cranked loco) . Where it differs somewhat from the norm is the use of a tender-mounted Portescap motor fitted with an in-line Maxon gearhead. The latter reduces the motor speed down by 16 to 1. This is connected to a Slaters UJ set up with the normal 2mm connecting rod thinned down to 1mm (using bushes at either ends) and this in turn is connected to a 3 to 1 floating gearbox driving the centre axle. At this ratio the gearbox is very efficient (although it cannot be "back-driven")and quiet. It is from a Rivarossi BIg Boy and bought for less than £5 off Ebay (from Dave Franks as it turned out!). I have had this running along a test track (can't run it on the layout yet as I don't have a decoder fitted) but initial impressions are that it is smooth, powerful and relatively quiet. There is some noise from the planetary gears but I hope they will quiten down when they are bedded in.
The drive shaft is (just) above footplate level, mainly to make life simple and keep everything in line as far as possible. Once the crew are added and some coal piled up in strategic spots I don't think it will be too noticeable. After all if it was good enough for the late great Sid Stubbs (see his Kirtley in MRJ 99 - the article that inspired this pale imitation), then it is certainly good enough for me.
My main reason for posting, other than to offer some general help to the OP, is to comment on the idea that a high level of torque in a tender mounted motor is sufficient to "topple" the tender. That may have been the case with big, heavy iron motors such as Romfords or Triang X04s but small modern coreless motors do not literally throw their weight about. I have gone from full speed one way to the other and there has not been a tremor, let alone a wobble.
The motor by the way was bought from a chap calling himself "The Motorman" operating from the US and contactable via his Ebay web site. Helpful chap and although the motors and gearboxes are not dear (in my opinion) by the time you have added in postage and tax they can be expensive. So far however it seems good value to me.

Here are some photos.

Bryan
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Tim V
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Re: Tender Powered 4-4-0

Postby Tim V » Thu Nov 22, 2012 9:22 pm

Very nice....
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Horsetan
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Re: Tender Powered 4-4-0

Postby Horsetan » Thu Nov 22, 2012 9:23 pm

hollybeau wrote:.....The motor by the way was bought from a chap calling himself "The Motorman" operating from the US and contactable via his Ebay web site. Helpful chap ....


Very good source of Maxons. They are generally more robust than Escaps, and have quite a lot of grunt.
That would be an ecumenical matter.

Kos
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Re: Tender Powered 4-4-0

Postby Kos » Thu Dec 06, 2012 8:38 pm

Thanks everyone for responding to my request for information and ideas. The outcome is as follows:

Loco 1 Dunalastair IV 4-4-0:

Currently running nose-heavy with not enough weight over the motor, which itself is over the drivers. Motor/gearbox = Mashima 14/1626 and High Level RR+ 54:1

Next job is to provide a new tender chassis with twin-beam over middle/trailing axles, and sprung leading. With enough weight added this will be connected so that weight is transferred to the loco.

Loco 2 Pickersgill 4-4-0:

This loco will have a Mashima 14/1626 in the tender with the drive shaft passing through the tender and loco coal holes to a High Level RRC+ 54:1 and a firebox and boiler otherwise filled with lead.

The tender will use the Dunalastair's current tender chassis, which has twin-beam on leading/middle axles and rocking rear axle.

Both locos have/will have sprung bogies and twin-beam compensated drivers.


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