Forum Options

« Back to Engines and Rolling Stock Topics

Sign In above to begin adding replies.
 

Romulus Valve Gear

Northerner

Joined: 12-04-12

Topics: 1

Replies: 6

Posted: Sun 20th Oct 2013, 12:27pm
Romulus Valve Gear

I have a Romulus 2-6-0 with Hackworth valve gear and would love to convert it to Walschaerts would anybody have any information or drawings on conversion.

Many thanks
Martin Sams
 

Replies To This Post

Rob Walker

Joined: 25-10-10

Topics: 6

Replies: 12

Posted: Mon 21st Oct 2013, 9:17pm

Hi Martin,

Could i ask if the 2-6-0 Romulus you have was built by drawings from the following website?

http://www.co2.pwp.blueyonder.co.uk/PAGE1.html

my father and i recently finished one with walschaerts if you look at the gallery page they are on there, at present on pages 22 (Katie & Merlin) and 26 (2-6-0 Romulus)

Regards

Rob
 

Xz

Joined: 1-01-92

Topics: 17

Replies: 244

Posted: Sun 27th Oct 2013, 4:01pm

Several members have done this successfully. There is currently a Romulus for sale on Preston Services site that was built by Harold Pearson in Cambodia, to the design drawn up by Don Ashton and printed in M.E.
 

Northerner

Joined: 12-04-12

Topics: 1

Replies: 6

Posted: Tue 29th Oct 2013, 11:24pm

Hi Rob and Xz
Thanks for your replies.
The loco described in the link is mine, which I purchased last year, don't ask how much work it need to run reasonable!.

I have managed to get the Hackworth valve gear to run in forward to an acceptable standard however reverse is another matter due to misalignment of the weight shaft, so I thought rather than do more work with the present gear I would change to Walschaerts. Would there be any chance of a copy of the valve gear layout and sizes Rob?? any costs involved I would pay for.

Merlin looks very smart.

Kind regards
Martin
 

Xz

Joined: 1-01-92

Topics: 17

Replies: 244

Posted: Wed 30th Oct 2013, 11:53am

You say misalignment of the weigh-shaft?? The correct position will depend on several factors. A line drawn between the axle centre and the weigh-shaft centre should be at right-angles to the centre-line of the cylinder. That should give the same movement into forward and reverse. The angle of the cylinder should allow its centreline to pass through the drive axle centre at running level. My thoughts are (without have seen it), that it would be a lot easier to correct any errors in the existing, rather than embark on another long road. There are some other factors to take into account for the Hackworth, but it is a simple, strong, very reliable valve gear, even if it does have it's detractors.

If you wish to discuss it further, feel free to give me a ring.

Bob Gray.
 

Peter Beevers

Joined: 9-10-01

Topics: 3

Replies: 134

Posted: Wed 30th Oct 2013, 4:51pm

I can only agree with Bob - simplicity is King here. Hackworth and Heywood valve gears aren't the best on the block but they're close enough are and SO simple.
 

WembleyLion

Joined: 1-01-87

Topics: 2

Replies: 34

Posted: Mon 4th Nov 2013, 10:51am

Hackworth valve gear is not only effected by the position of the weigh-shaft on the frame but also by its height above the axle centre. The loco moving on its springs will have a significent effect on the valve timing, especially in long cut-offs. Often locos with Hackworth gear have rubber block suspension on the rear axle to overcome this problem.

No valve gear other than gear driven rotary cam gear is perfect in both forward and reverse positions and even in full size the gear on tender engines was set to the best events in forward gear; tank engines were a compromise of the best events available in both directions.

John
 

WembleyLion

Joined: 1-01-87

Topics: 2

Replies: 34

Posted: Mon 4th Nov 2013, 10:23pm

Martin,

Just a thought; I remember that many moons ago the late Rodney Weaver penned an article in the News regarding errors in the Romulus valve gear. If I remember correctly he stated that the vibrating link and or return crank pin centres were incorrect and offered his reasons.

Knowing Rodney's quest for accuracy I suspect his calculations were right but I doubt this information was transferred to the drawings.

It might be worth looking this article up; it may save you a lot of work.

John
 

Xz

Joined: 1-01-92

Topics: 17

Replies: 244

Posted: Tue 5th Nov 2013, 7:04pm

Unfortunately I found Rodney's article of little assistance, when correcting a poorly made example, last year. The height of the weigh-shaft is determined in conjunction with the proportions of the vibrating link, which is further determined by the ride height and therefore the stiffness (or otherwise) of the rear suspension. Over-stiffening the suspension does not correct anything, merely disguises it. Lengths and heights are only part of the equation. Suffice to say that I got my head around the problems and the afflicted loco now runs very sweetly.
 

Northerner

Joined: 12-04-12

Topics: 1

Replies: 6

Posted: Tue 5th Nov 2013, 10:45pm

Gentlemen
Many thanks for all the information you have posted. One of the many things I had to do to this loco was stiffen the springing, it rolled like the a ship on a rough sea, this did alter the valve gear alignment, which was then reset however I still have a desire to fit Walschaerts, maybe I just like work, I now have a computer valve gear program and plan to attempt the design myself next year.

Still would like to find drawings though

Martin
 

Xz

Joined: 1-01-92

Topics: 17

Replies: 244

Posted: Sat 9th Nov 2013, 7:25pm

From a design point of view it would ride better if the leaf springs were on the rear, or better still all round. Leaf springs have an element of self damping which of course coils do not. To convert to any other type of valve gear is a job for its own sake, and will no doubt be very satisfying, once completed. As a base for such experiments there is probably none better than a Rommy, either four or six wheeled. Good luck with your endeavours, this game is about doing what you enjoy. It might be nice if you were to do a write-up for the mag afterwards.
 

Northerner

Joined: 12-04-12

Topics: 1

Replies: 6

Posted: Sun 10th Nov 2013, 10:06pm

Thanks for your comments Xz. I put coil springs in which are virtually solid as I did not have time to make new leaf springs, this improved the handling and the valve timing, in other words I now do not have to guess which way the fire box door is going to leap. I might be tempted to put finger to keys, but don't hold your breath as I am going to warmer climates for a little while.

Martin
 
 
« Back to Engines and Rolling Stock Topics

Web design by Slingshot