Easybuild DMU power bogie for S7

[Dog Star]

S7 is EASY... or so the saying goes.

Um, this topic has me foxed at the moment. What does the S7 novice do when confronted with the contents of an Easybuild DMU kit as he thinks "Easy to build, should be able to get the motor bogie running by teatime"? What does he see in the box?

* 21mm FS steel wheels on 3/16" OD axles;
* wheel seat of circa 4mm diameter and 2mm journals;
* Delrin sprocket force fit on axle;
* Brass worm wheel retained on axle by grub screw.

Initial inspection suggests that moving the wheels out to S7 B-2-B may be successful, just not sure given that the length of the wheel seat is the thickness of the wheel boss. At this time I have not been able to move one of the wheels along the axle and so the extra B-2-B is taken on one side. Anyone any idea as to how/where the Easybuild wheels are insulated?

If I replace the wheelsets a possible route seems to be:-

* Slater's DMU driving wheels;
* S7 axles;
* 2mm Journal extension screws (because the Easybuild wheelsets run in outside bearings).

If this is possible, then what chance that the Delrin sprocket can be moved from an Easybuild wheelset to the Slater's S7 axle?

Any S7 modeller got an Easybuild DMU running on 33mm track?

Thanks, Graham

 

[Osgood]

And what use is a Delrin sprocket without chain?

 

[SimonT]

Graham,
if you are coming to Steam you can have a look under my 117. Like most of the stock, it is already packed, so photos won't happen until after the show as I am currently trying to solder up a mile of spear point fencing for the island platform.
SimonT

 

[daifly]

Graham
Did you come to a conclusion on how to tackle this?

Simon
Did the bogie undergubbins photos get taken? If so, please can we see them!

Cheers
Dave (EB 121 still in the box)

 

[Dog Star]

Graham. Did you come to a conclusion on how to tackle this?

Simon. Did the bogie undergubbins photos get taken? If so, please can we see them!

At this time the boxes have been promoted to Shelf Queen status or since there are three boxes, "Shelf Triplets". Steph has written about a drive arrangement for 8' 6" bogies, I cannot recall if there was a photo in the relevant topic.

regards, Graham

 

[flexible_coupling]

There was an encouraging photo from Steph using the 14mm Mashima motor, which is relevant to my future interests of building little Simplex locos....

 

[daifly]

Thanks Graham. I was wondering if there was a suitable method of modifying and using the wheels rather than go to the expense of buying new ones. Did you modify the wheel profile and thickness for S7 before consigning the project to the Royal shelf?
Cheers
Dave

 

[Dog Star]

I was wondering if there was a suitable method of modifying and using the wheels rather than go to the expense of buying new ones. Did you modify the wheel profile and thickness for S7 before consigning the project to the Royal shelf?

Dave, nothing has been done on the matter since the DMU kits were promoted to regal status... other than wait on a suitable Steph Dale design. I think that re-profiling of the tyres is possible provided that a suitable mandrel is available.

 

[daifly]

Thanks Graham.

I don't think that the drive is going to be the issue for me. It is the wheel profile and thickness to fit within the bogie frame.

Close examination of my EB driver wheelsets suggests that they are insulated with an insert at each end of the axle.As you know, they have extended journals for outside bearings.

I have also got a Westdale version of the Class 121/2 which again has a 3/16" axle but is insulated by centre insert on one side only. The wheel at the opposite end of the axle screws on to a threaded axle so that the axle is live. They may be these wheels. The Westdale bogie design uses inside bearings. The axles are slightly overlength and with some judicious thinning and packing could possibly be converted for S7 use.

Further thought and investigation required.

Cheers

Dave

 

[Ressaldar]

The unit that Steph has built for me (shameless plug from a very satisfied customer) for my 121 Sandite I think uses Peartree wheelsets and they I believe are also available in S7 - this might therefore be the answer - but check with Steph first.

cheers

Mike

 

[daifly]

The unit that Steph has built for me (shameless plug from a very satisfied customer) for my 121 Sandite I think uses Peartree wheelsets and they I believe are also available in S7 - this might therefore be the answer - but check with Steph first.

I wish that they did, Mike. Sadly, loco wheels are only available in FS. At £5/axle though they do lend themselves to some economical attempts at bodgery!

 

[Ressaldar]

The Peartree advert on page 95 of the current Gazette states Scale 7 wheels for 3'1" 3 hole wagon, 3'7" coach and 3'7" Mansell and lower down says "New manufacturing service for special size wheels and machined parts" so presumably 3'1" wheels for B4 and DMU bogies will fall into that category?

Happy hunting.

cheers

Mike

 

[Steph Dale]

At this time the boxes have been promoted to Shelf Queen status or since there are three boxes, "Shelf Triplets". Steph has written about a drive arrangement for 8' 6" bogies, I cannot recall if there was a photo in the relevant topic.

regards, Graham

I did (and you 'like'd the post!) it's here: http://www.westernthunder.co.uk/ind...-really-quite-narrow.2445/page-14#post-103461

I wish that they did, Mike. Sadly, loco wheels are only available in FS. At £5/axle though they do lend themselves to some economical attempts at bodgery!

At Mike's suggestion I used Peartree's 3'-ish carriage wheels. The wheel and insulating bush can be pressed off and back on the axle without a huge amount of grief.

Guys,
The 13:1 gearbox for Mashima 14xx and 16xx was not tooled to production as I couldn't imagine an application when I first drew them up. Mike's bogie uses the engineering prototype. I'll refresh the artwork and get them in the next batch of etches, which I imagine will be early in the New Year as it now looks as though they'll be quite popular; I'm even considering using them to drive a Type 1 or Type 2 Bo-Bo (I've got a Steve Beattie 10800 kit) as I suspect the performance would be rather good, especially if I can sort out a decent sprung bogie.
Steph

 

[Dog Star]

The 13:1 gearbox for Mashima 14xx and 16xx was not tooled to production as I couldn't imagine an application when I first drew them up. ... I'll refresh the artwork and get them in the next batch of etches...

Steph,

I am not familiar with either of those motors... so please try to answer this question. What is the likely scale maximum speed of a DMU with your choice of motor and gearbox? Not knowledgeable on these early diesel units so I am not sure of the wheel diameter.

thanks, Graham

 

[Steph Dale]

Hmm, just looked at the data for the application using the Mashima 1430 (11000rpm no load, 3'0" wheels, 13:1 gearbox) and the answer is 88smph at 100% efficiency. If your build is perfect you might get 80mph out of it, but 70smph is a bit more likely. I'm probably assuming that all bearings are ball-races in these estimations, you'll be a bit slower still if you're using plain bearings. Efficiency won't be at all bad at low gear ratios and with ball races...

The slow speed is good too; these are surprisingly good motors and manage very impressive torque for their size, especially under DCC. The smaller motors (1420, 1424, 1426) will go faster and the 1428, 1430, 1628 and 1630 are all much of a muchness as regards performance.

Steph

 

[Scale7JB]

Very interested to see how this goes...

Don't tell anyone, but I do fancy one of EasiBuilds parcels units...!

JB.

 

[Pugsley]

What? A diesel?

 

[Dog Star]

Steph,

Thank you for providing a link to the original posts relating to the DMU 8'6" bogie design. What do you have in the way of cross-section and side-elevation drawings? We are thinking of a four car First Generation DMU set so how many driven motor bogies might be needed for running on a level road?

Richard raised the question of RTR DMU bogies - what do you think about providing such for the Easybuild range?

regards, Graham

 

[Steph Dale]

Thank you for providing a link to the original posts relating to the DMU 8'6" bogie design. What do you have in the way of cross-section and side-elevation drawings?

This is all I did - as I just needed to check clearances over the motor for the Wayoh bogie and its modified pivot:

Width? Well, the gearbox and an unadulterated Delrin sprocket fit comfortably inside an inside-bearing set of frames, so it's not a bulky power pack at all.

We are thinking of a four car First Generation DMU set so how many driven motor bogies might be needed for running on a level road?

That's a question that Mike will be better able to answer - perhaps he can rig something up to do a quick test of how many additional vehicles could be hauled. I suggested to Mike that prototypical performance is quite likely; i.e. two axles driven per motor car and you'd be able to run with an unpowered trailer. The end performance will depend on a whole load of things (including the weight of each vehicle and how well they run), but I've got very heavy whitemetal-bodied HO locos with these motors in and they'll pull the side off a house (like 16 carriages with close couplings on an s-bend up a gradient)...

Richard raised the question of RTR DMU bogies - what do you think about providing such for the Easybuild range?

When the gearboxes are available it's certainly possible. The problem is that different people will want different things, but yes; I'm happy to provide r-t-r. I will be costing a 'Pack price' (Motor, gearbox, delrin drive) for those interested in a solution they can fit themselves. The gearboxes will be available flat (i.e. self-assembly) or ex-works, as preferred.

Steph

 

[Dog Star]

This is all I did - as I just needed to check clearances over the motor for the Wayoh bogie and its modified pivot.

I suggested to Mike that prototypical performance is quite likely; i.e. two axles driven per motor car and you'd be able to run with an unpowered trailer.

When the gearboxes are available it's certainly possible. The problem is that different people will want different things, but yes; I'm happy to provide r-t-r.

Thank you Steph,

The side-elevation suggest that the bogie mount is going to be above floor level... or have I mis-read your solution?

Your suggested performance... one powered motor bogie for one power car and one trailer car - or two power cars plus one trailer car?

I am not sure why I would want something that was different to a solution that is acceptable to Heyside. Do you wish to take this RTR discussion off-line?