gearbox designs for sprung BO-BO or Co-Co bogies

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Simon_S
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby Simon_S » Mon Sep 05, 2016 10:37 am

junctionmad wrote:
PeteT wrote:Thanks. It looks like this clag design is interesting as it drives two axles on each bogie but only needs one transfer box. My concern is that the transfer box then is in the middle of the loco and severely limits the motor size
which is opposite to the whole point of a central motor


I built one of these and can report that there's plenty of room for the motor and a flywheel in a 31. The main problem is that the central transfer box results in short driveshafts to the bogies which restricts their rotation. I got over this by arranging for the transfer box to slide laterally.

If I were to do another project like this, I'd use a central motor with long driveshafts to transfer boxes on the outer ends of each bogie to minimise driveshaft articulation.

Regards,
Simon

junctionmad
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby junctionmad » Mon Sep 05, 2016 10:52 am

Simon_S wrote:
junctionmad wrote:
PeteT wrote:Thanks. It looks like this clag design is interesting as it drives two axles on each bogie but only needs one transfer box. My concern is that the transfer box then is in the middle of the loco and severely limits the motor size
which is opposite to the whole point of a central motor


I built one of these and can report that there's plenty of room for the motor and a flywheel in a 31. The main problem is that the central transfer box results in short driveshafts to the bogies which restricts their rotation. I got over this by arranging for the transfer box to slide laterally.

If I were to do another project like this, I'd use a central motor with long driveshafts to transfer boxes on the outer ends of each bogie to minimise driveshaft articulation.

Regards,
Simon

Thanks a good point

Crepello
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby Crepello » Mon Sep 05, 2016 8:38 pm

Simon_S wrote:If I were to do another project like this, I'd use a central motor with long driveshafts to transfer boxes on the outer ends of each bogie to minimise driveshaft articulation.

You are homing in on a configuration described around 1975 in a P4 Society newsletter. The infuriating thing about 'doing it correctly', based on thinking through the kinematics, in a bogie diesel is the amount of close tolerance components required in 2-,4-,6-,8- or 12-off quantities. The cost quickly goes stratospheric. The current generation of RTR have hit on just about the optimum compromise, bulk and flexibility apart. To adopt it means accepting a semi-bodge in the form of floppy gear meshes.

junctionmad
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby junctionmad » Mon Sep 05, 2016 10:10 pm

Crepello wrote:
Simon_S wrote:If I were to do another project like this, I'd use a central motor with long driveshafts to transfer boxes on the outer ends of each bogie to minimise driveshaft articulation.

You are homing in on a configuration described around 1975 in a P4 Society newsletter. The infuriating thing about 'doing it correctly', based on thinking through the kinematics, in a bogie diesel is the amount of close tolerance components required in 2-,4-,6-,8- or 12-off quantities. The cost quickly goes stratospheric. The current generation of RTR have hit on just about the optimum compromise, bulk and flexibility apart. To adopt it means accepting a semi-bodge in the form of floppy gear meshes.


Hmmm , mousa gearboxes are around 14 quid a pair. , plus some UJ from tubing and the extra transfer gearbox that has to be scratch built. Let's say 20 quid a bogie. Hardly stratospheric, floppy gears I don't beleive are compatible with fully sprung and would more then likely cost more to assemble from scratch

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grovenor-2685
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby grovenor-2685 » Mon Sep 05, 2016 10:25 pm

and the extra transfer gearbox that has to be scratch built.
Why does it have to be scratch built? There have been a variety of designs on sale over the years. I don't think have they all disappeared, High Level has one in his list "TendeRiser!
Regards

junctionmad
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby junctionmad » Tue Sep 06, 2016 5:24 am

grovenor-2685 wrote:
and the extra transfer gearbox that has to be scratch built.
Why does it have to be scratch built? There have been a variety of designs on sale over the years. I don't think have they all disappeared, High Level has one in his list "TendeRiser!
Regards


Keith , you are perfectly correct. There is the high level unit (1:1) . I'm not aware of any others. My own preference is a 2:1 transfer box to keep the axle hung ratios as low as possible and hence small. ( 15:1) . I've been looking at at the Athearne idea of half axles and bushed worm gears

Dave

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jjnewitt
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby jjnewitt » Tue Sep 06, 2016 6:44 am

junctionmad wrote: floppy gears I don't beleive are compatible with fully sprung and would more then likely cost more to assemble from scratch


Nothing wrong with floppy gears in RTR drivetrains, it is the very reason why they can be used sucsessfully in fully sprung bogies. The slop gives room for movement. Personally I would get hold of some RTR gears and make up a drivetrain just like the RTR boys do. The system works really well.

By the way what is the prototype you're proposing thses bogies for, I'm not sure you've said?

In addition to the thread that Russ linked to, and in case you've missed it, I also created a thread on scratch building a pair of fully sprung class 47 bogies.

Justin

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jim s-w
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby jim s-w » Tue Sep 06, 2016 7:34 am

I know this is going to upset the engineering types that measure things with fag papers but floppy is good in diesels. If you take a couple of US diesels like the PA1 (what we had to use to get any form of central motor drive in the old days) you had 2 options. athearn and lifelike. Lifelike seemed to be engineered like a watch with athearn were all rattly and floppy. Fit p4 wheels and athearn was sure footed and would run all day while lifelike was a knightmare. Yes lifelike were dead quiet but then so was athearn if you knocked it off the road!

junctionmad
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby junctionmad » Tue Sep 06, 2016 10:10 am

jjnewitt wrote:
junctionmad wrote: floppy gears I don't beleive are compatible with fully sprung and would more then likely cost more to assemble from scratch


Nothing wrong with floppy gears in RTR drivetrains, it is the very reason why they can be used sucsessfully in fully sprung bogies. The slop gives room for movement. Personally I would get hold of some RTR gears and make up a drivetrain just like the RTR boys do. The system works really well.

By the way what is the prototype you're proposing thses bogies for, I'm not sure you've said?

In addition to the thread that Russ linked to, and in case you've missed it, I also created a thread on scratch building a pair of fully sprung class 47 bogies.

Justin



Thank you Justin , very interesting link. The prototype is not common , CIE Sulzer B101 class ,built by the Birmingham railway carriage and wagon company , engine built by vickers armstrong http://www.derbysulzers.com/cie.html !!

Armchair Modeller
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby Armchair Modeller » Tue Sep 06, 2016 11:28 am

With a w/b of 10ft 6in, you could surely adapt a Class 26/27 chassis or even a High Level Longrider bogie for much less bother - especially if the centre axles are not driven?

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jim s-w
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby jim s-w » Tue Sep 06, 2016 2:20 pm

The 26 is too short but a warship or hymek are 10ft 6 wheelbase overall. You used to be able to get hymek bogies from howes

HTH

Jim

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jjnewitt
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby jjnewitt » Tue Sep 06, 2016 2:58 pm

junctionmad wrote:Thank you Justin , very interesting link. The prototype is not common , CIE Sulzer B101 class ,built by the Birmingham railway carriage and wagon company , engine built by vickers armstrong http://www.derbysulzers.com/cie.html !!


Thanks for the link. Interesting class. Those front cab windows are quite small aren't they, I wonder what forward visability was like? The Bo-Bos are also quite fun, they have an odd expression to them!

I'd echo Jim's idea. If you can get hold of a set of Heljan Hymek drivetrains. There should be enough room between the gears to cut a slot for a centre axle, then mount everything in a set of sprung bogies. Much easier than putting something together with gearboxes, trasfer boxes and U/Js and it will work just as well.

Justin

junctionmad
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby junctionmad » Tue Sep 06, 2016 4:07 pm

jjnewitt wrote:
junctionmad wrote:Thank you Justin , very interesting link. The prototype is not common , CIE Sulzer B101 class ,built by the Birmingham railway carriage and wagon company , engine built by vickers armstrong http://www.derbysulzers.com/cie.html !!


Thanks for the link. Interesting class. Those front cab windows are quite small aren't they, I wonder what forward visability was like? The Bo-Bos are also quite fun, they have an odd expression to them!

I'd echo Jim's idea. If you can get hold of a set of Heljan Hymek drivetrains. There should be enough room between the gears to cut a slot for a centre axle, then mount everything in a set of sprung bogies. Much easier than putting something together with gearboxes, trasfer boxes and U/Js and it will work just as well.

Justin


hmm , I think Id prefer to go down the floating gearbox route , its not expensive

junctionmad
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby junctionmad » Tue Sep 06, 2016 4:10 pm

jjnewitt wrote:
junctionmad wrote:Thank you Justin , very interesting link. The prototype is not common , CIE Sulzer B101 class ,built by the Birmingham railway carriage and wagon company , engine built by vickers armstrong http://www.derbysulzers.com/cie.html !!


Thanks for the link. Interesting class. Those front cab windows are quite small aren't they, I wonder what forward visability was like? The Bo-Bos are also quite fun, they have an odd expression to them!



CIEs early Sulzers Bo-bo( only two built ) were the last engines basically built at Inchicore and very very quirky , The B101 series was much more standard and proved good engines lasting quite late ( in to the late seventies )

when I was 15 I got to drive one of the B101s down a short length of siding, ah the days before H&S

Terry Bendall
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby Terry Bendall » Fri Sep 09, 2016 7:00 am

junctionmad wrote:The prototype is not common , CIE Sulzer B101 class ,built by the Birmingham railway carriage and wagon company


Which presumable means that the track is 21mm which makes things even more interesting. Is there/will there be a layout for it to run on?

Terry Bendall

junctionmad
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby junctionmad » Fri Sep 09, 2016 8:02 am

Terry Bendall wrote:
junctionmad wrote:The prototype is not common , CIE Sulzer B101 class ,built by the Birmingham railway carriage and wagon company


Which presumable means that the track is 21mm which makes things even more interesting. Is there/will there be a layout for it to run on?

Terry Bendall



21mm yes. The layout hasn't been decided , maybe my p4 test plank will be this

image.jpeg
image.jpeg (288.33 KiB) Viewed 3793 times

(Copyright Eiretrains)

Gort Station , Co Galway in the early 70s , it's was reopened in a the last frw years and while most of the track is gone, all the primary structures remain ( water tower , goods shed and station house ) signal cabin is gone

However the layout is still a twinkle in the eye.

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Horsetan
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby Horsetan » Wed Oct 12, 2016 10:48 pm

jjnewitt wrote:... If you can get hold of a set of Heljan Hymek drivetrains. There should be enough room between the gears to cut a slot for a centre axle, then mount everything in a set of sprung bogies. Much easier than putting something together with gearboxes, trasfer boxes and U/Js and it will work just as well.


I'll declare an interest as I also have a CIE 101 to run on 21mm gauge. This is the Studio Scale Models resin body with its own underframe etch, designed to take Lima Deltic bogies as a quickie option.

I did this a while ago with some Heljan spares, and found there is only just enough room in the Heljan Hymek bogie for a central axle to run under the geartrain, just missing the gear teeth. There is no room for it to rise any further.

On the face of it, you could try using the Penbits sprung Hymek bogie kit, but it has brackets in the exact spot where the central axle would be, so quite a bit of redesign would be required to make it suitable for a CIE 101
That would be an ecumenical matter.

junctionmad
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Re: gearbox designs for sprung BO-BO or Co-Co bogies

Postby junctionmad » Wed Oct 12, 2016 11:01 pm

Horsetan wrote:
jjnewitt wrote:... If you can get hold of a set of Heljan Hymek drivetrains. There should be enough room between the gears to cut a slot for a centre axle, then mount everything in a set of sprung bogies. Much easier than putting something together with gearboxes, trasfer boxes and U/Js and it will work just as well.


I'll declare an interest as I also have a CIE 101 to run on 21mm gauge. This is the Studio Scale Models resin body with its own underframe etch, designed to take Lima Deltic bogies as a quickie option.

I did this a while ago with some Heljan spares, and found there is only just enough room in the Heljan Hymek bogie for a central axle to run under the geartrain, just missing the gear teeth. There is no room for it to rise any further.

On the face of it, you could try using the Penbits sprung Hymek bogie kit, but it has brackets in the exact spot where the central axle would be, so quite a bit of redesign would be required to make it suitable for a CIE 101



I have begun to mill the new frames and work up the cad for the new gearboxes


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