Model Engineer issue 4743 **FREE 20 PAGE PREVIEW**

❖❖

LLANELLI SPRING RALLY Join our online community www.model-engineer.co.uk

Vol. 232 No. 4743 17 – 30 May 2024

Oscillators

THE ORIGINAL MAGAZINE FOR MODEL ENGINEERS

Novel design approaches to oscillating engines

Short wheelbase Foden steam lorry

Steam Engine Flying Scotsman Llanelli Trevithick patents his steam engine

Reversing stand for an LNER A3

Popular spring rally at Pembrey Park

687

709

Published by Mortons Media Group Ltd, Media Centre, Morton Way, Horncastle, Lincs LN9 6JR Tel: 01507 529589 Fax: 01507 371066 © 2023 Mortons Media ISSN 0026-7325 www.model-engineer.co.uk EDITORIAL Editor: Martin R. Evans MEeditor@mortons.co.uk Deputy editor: Diane Carney Designer: Druck Media Pvt. Ltd. Club News: Geoff Theasby Illustrator: Grahame Chambers Publisher: Steve O’Hara CUSTOMER SERVICES General Queries and Back Issues 01507 529529 Monday-Friday: 8.30am-5pm Answerphone 24hr help@classicmagazines.co.uk www.classicmagazines.co.uk ADVERTISING GROUP HEAD OF INVESTMENT – Lifestyle & Tractor Publications | www.talk-media.uk Mason Ponti mason@talk-media.uk A: Talk Media, The Granary, Downs Court, Yalding Hill, Yalding, Kent ME18 6AL Investment Manager: Karen Davies karen@talk-media.uk PUBLISHING Sales and distribution manager: Carl Smith Marketing manager: Charlotte Park Commercial director: Nigel Hole Publishing director: Dan Savage SUBSCRIPTION Full subscription rates (but see page 666 for offer): (12 months, 26 issues, inc post and packing) – UK £128.70. Export rates are also available, UK subscriptions are zero-rated for the purposes of Value Added Tax. Enquiries: subscriptions@mortons.co.uk PRINT AND DISTRIBUTIONS Printed by: William Gibbons & Son, 26 Planetary Road, Willenhall, West Midlands, WV13 3XB Distribution by: Seymour Distribution Limited, 2 East Poultry Avenue, London EC1A 9PT EDITORIAL CONTRIBUTION Accepted photographs and articles will be paid for upon publication. Items we cannot use will be returned if accompanied by a stamped addressed envelope and recorded delivery must clearly state so and enclose sufficient postage. In common with practice on other periodicals, all material is sent or returned at the contributor’s own risk and neither Model Engineer, the editor, the staff nor Mortons Media Ltd can be held responsible for loss or damage, howsoever caused. The opinions expressed in Model Engineer are not necessarily those of the editor or staff. This periodical must not, without the written consent of the publishers first being given, be lent, sold, hired out or otherwise disposed of in a mutilated condition or in other unauthorised cover by way of trade or annexed to or as part of any publication or advertising, literary or pictorial manner whatsoever.

SUBSCR & SAVE UP IBE TO 49% See page 66 6

Vol.232 No.4743 17–30 May 2024 668 SMOKE RINGS News, views and comment on the world of model engineering.

669 FLYING SCOTSMAN IN 5 INCH GAUGE Peter Seymour-Howell builds a highly detailed A3 locomotive based on Don Young’s drawings.

for details.

692 THE STATIONARY STEAM ENGINE Ron Fitzgerald tells the story of the development of the stationary steam engine.

696 BUTTERSIDE DOWN Steve Goodbody returns with further tales of the trials and tribulations of a model engineer’s life.

673 LLANELLI’S SPRING RALLY John Arrowsmith visits Pembrey Park to attend Llanelli’s popular spring rally.

678 OSCILLATING ENGINE DESIGN Martin Gearing takes a look at some novel approaches to oscillating engines.

682 LNER B1 LOCOMOTIVE Doug Hewson presents a true to scale fiveinch gauge model of Thompson’s B1.

686 BOOK REVIEW Roger Backhouse reads Simon Martin’s book on the life and work of Sir Nigel Gresley.

700 REDESIGNING A GAS BURNER Graham Astbury modifies T.E. Haynes’s original burner design for a hot air engine to run on propane rather than town gas.

705 AN ADMIRALTY CASE FOR A REGULATOR Adrian Garner shows that making an elegant case for a regulator timepiece does not require sophisticated woodworking skills.

709 BUILDING 3020 CORNWALL IN 5 INCH GAUGE Jim Clark builds a model of Francis Trevithick’s LNWR 2-2-2 locomotive.

687 POSTBAG 712 CLUB NEWS

Readers’ letters.

688 A TWIN TANDEM COMPOUND STEAM ENGINE Graeme Quayle presents an interesting design for a compound winding engine.

Geoff Theasby compiles the latest from model engineering clubs around the world.

715 CLUB DIARY Future Events.

❖❖

LLANELLI SPRING RALLY Join our online community www.model-engineer.co.uk

Vol. 232 No. 4743 17 – 30 May 2024

Oscillators

http://www.facebook.com/modelengineersworkshop

THE ORIGINAL MAGAZINE FOR MODEL ENGINEERS

Novel design approaches to oscillating engines

Short wheelbase Foden steam lorry

http://twitter.com/ modelengineers

ON THE COVER...

A short wheel base Foden steam lorry built from a Steam Tractor World kit by James Dowling (photo by John Arrowsmith).

£5.10

Steam Engine Flying Scotsman Llanelli Trevithick patents his steam engine

www.model-engineer.co.uk

Reversing stand for an LNER A3

Popular spring rally at Pembrey Park

This issue was published on May 17, 2024.

The next will be on sale on May 31, 2024.

www.model-engineer.co.uk

663

SUBSCRIBE AND SAVE Enjoy 12 months for just £68

PRINT ONLY

PRINT + DIGITAL

Quarterly direct debit for £19 Quarterly direct debit for £22* 1 year direct debit for £85* 1 year direct debit for £68 1 year credit/debit card for £74 1 year credit/debit card for £88*

DIGITAL ONLY 1 year direct debit for £50* 1 year credit/debit card for £54* *Any digital subscription package includes access to the online archive.

Great reasons to subscribe >> Free UK delivery to your door or instant download to your digital device >> Save money on shop prices >> Never miss an issue >> Receive your issue before it goes on sale in the shop

( classicmagazines.co.uk/MEDPS 8 01507 529529 and quote MEDPS Lines are open from 8.30am-5pm weekdays GMT

Offer ends December 31, 2024. Subscriptions will start with the next available issue. Direct Debit payments will continue on the agreed plan unless you tell us otherwise.

To view the privacy policy for MMG Ltd (publisher of Model Engineer), please visit www.mortons.co.uk/privacy Please visit www.classicmagazines.co.uk/terms for full terms & conditions.

Following the event, there will be a public running day on Sunday the 1st of September 2024 which all attendees and families are invited to take part.

FMES Rally

MARTIN EVANS Editor

DIANE CARNEY Assistant Editor

Martin Evans can be contacted on the mobile number or email below and would be delighted to receive your contributions, in the form of items of correspondence, comment or articles.

07710-192953 MEeditor@mortons.co.uk

This year the Federation of Model Engineering Society Rally is being held at the Nottingham Society of Model and Experimental Engineers at their Ruddington headquarters on the 31st of August. Set in the Nottingham Transport Heritage Centre in Ruddington, the railway includes a kilometre of 7¼ inch gauge ground level track with gradients of up to 1 in 85 and almost ½ mile of 3½ and 5-inch gauge raised track where gradients up to a maximum of 1 in 115 and tunnels add interest to this attractive railway. The club will also welcome visitors with miniature traction engines and other examples of the hobby to show and enter the Federation Autumn Rally Competition.

The rally is open to all members of clubs affiliated with the Federation. Please visit the club website (www. nsmee.org.uk) for more information on this event.

On the day of the rally, all visitors with eligible models are invited to enter the two competitions that will be held. These are the regular Australian Association of Live Steamers (AALS) trophy and the Federation Autumn Rally Competition. The rules for both competitions can be found on the FMES website (fmes.org. uk/project/fmes-autumn-rallyat-nottingham). For the club to plan the resources properly for hosting visitors, please complete the booking form on the club rally page as soon as possible.

are available. The highlight of each day is the steam road run down into the village to the White Lion pub. Exhibitors are welcome and if you would like to bring along a model, a booking form is available at mmdmes.wixsite.com/home/ steamweekend2024

Bradford Cup

NSMEE

FMES Rally

Whissendine

This year’s steam rally at Whissendine, Rutland, organised by the Melton Mowbray and District Model Engineering Society, takes place on the weekend of June the 1st and 2nd, at the Whissendine Sports Club ground. Entry is free and refreshments and steam rides

Do not forget to vote for the Bradford Cup, awarded each year to the writer of the best article in Model Engineer in the previous year. This year’s nominations are: The Stationary Steam Engine – Ron Fitzgerald Radial Valve Gears Again – Duncan Webster Fire Queen – Luker Please register your vote with me before the end of May – one vote of course per reader.

Here is a picture of the trophy, to be awarded to the lucky winner. The picture was taken at the National Railway Museum, York, during the award of the cup to last year’s winner, Steve Goodbody, but which locomotive is it sitting on? No prizes for correct guesses, I’m afraid…

Cock-up Corner In the Club Diary last time, I wrongly claimed the Parklands week at Hemsby would take place during the first week of June. That is incorrect – it will actually take place during the last week of May, starting on May 25th.

Whissendine

668

Model Engineer 17 May 2024

Flying Scotsman in 5 Inch Gauge

PART 59 – REVERSER STAND (CONTINUED)

n the last article we had the reverser ready for brazing but we’re not ready for that stage et e first need to transfer the mounting holes to the reverser stool which, of course, hasn’t yet been made and then work out the exact position of the stool which will sit in between the main and trailing frames.

The stool itself is a simple rectangle of inches made to fit from a length of 7/16 inch steel. Not having anything close to that size I machined from the closest size in stock which was 75mm x 50mm x 12mm - a wee bit of machining required. I used a grinder to get close to size and then machined to size and thickness not a fi e minute job. With the stool machined/ squared to size, the next stage was to machine a channel into the underside creating a U channel. Don states to machine a channel lea ing inch on the side to the trailing frame and a little wider on the other side to give enough metal to tap into once this side has been tapered to match the main frame (photo 1

I

Peter SeymourHowell builds a fine, fully detailed model of Gresley’s iconic locomotive to Don Young’s drawings.

Continued from p.129, M.E.4734, January 12

1

First milling operation on the reverser stool.

www.model-engineer.co.uk

2

One half of the backhead fitted temporarily. o work out the taper first needed to take into account the reverser’s relative distance back from the backhead to allow for heat expansion; Don advises to allow for 5/32 inch.

Before I can do this I needed to place the backhead roughly in position. The backhead sections were cut from steel b d odel ngineers aser some time ago and at the time I thought the plotted holes might need moving but now that I’ve had time to look at this more closely they just needed a little fettling to fit Photograph 2 shows one-half of the backhead temporally held using two 3 mm screws into the mounting bushes kindl fitted b aul outhern oilers td onl need to fit the side of the re erser for now. Note that the two tapped

bushes at the bottom will be fitted with blanking plugs with the corner bush being fitted with a washout plug for boiler cleaning. The outside edge will of course be formed to curve around the outer edge of the backhead.

With the backhead positioned, I could then place the stool roughly in place and sit the reverser on top (photo 3 had left drilling the mounting holes into the stool until this stage just in case I had missed anything (I did details later can now see that I can drill said holes ready for mounting the reverser once bra ed again more on that later. In the photograph I have rested the stool with its finished edge up against the inner trailing frame edge allowing the inch mm gap between the reverser and boiler.

3

Establishing the position of the reverser stool.

669

>>

4

6

Judging the taper required on the frame edge.

5

8

Checking the space behind the backhead for insulation.

9

Drilling the reverser mounting plates in the stool.

7

Six holes transferred from the mounting plate to the stool.

Checking the reverser stool for fit.

Filing the taper on the stool.

With the reverser in place, I could see/judge the taper required on the main frame edge and, as can be seen in photo 4, it’s not a lot. I also noted that I need to either remove a little from the frame stiffener or the stool. I’ll opt for the stool.

I then marked the edge that requires tapering, the plan being to first achie e the correct taper and then remove metal until the stool fits between the frames s ou can see in photo 5 there’s not much to remove and so I did so with a hand file

670

I then needed to transfer the reverser mounting plate holes to the stool. To do this I held the stool in the machine vice along with the mounting plate sitting on top drilled the first hole from this, plotted at zero, and then the rest using the DRO (photo 6 In photo 7 we can see the six holes now transferred. Note that these are at No. 42 tapping size for with the mounting plate holes requiring to be drilled out for clearance No. 34. later.

It was now time to decide on the re erser s final position while checking for Don’s suggested expansion allowance gap. I also needed to be mindful that the backhead cleading will have some insulation sandwiched between it and the boiler s photo 8 shows, there’s not a lot of

room so I have left the cleading mounting bushes as supplied which gives just enough room to clear the copper stay heads and allowance for some insulation material. s mentioned filed the taper by hand and checked for fit photo 9 on s drawing shows that two of the mounting holes into the mainframes are shared with the drag box stiffener. I am not going to use these as fitting them would be more than a little problematic. I have also shaped the rear of the stool to clear said stiffener.

With the stool in position, I placed the reverser on it using a couple of No.42 drills to hold it in place while I checked the gap; the gap here is just under 5mm so a little larger than Don stated (photo 10

To transfer the inner bolt holes first marked the holes with a fine point pen not easy to reach this area, so transferring holes in the normal wa is not possible and then set the stool up to use the DRO for drilling the holes to match those in the mainframes. With the holes drilled and tapped I made life a little easier by putting a point on the bolts as shown in photo 11.

In photo 12 we see the three bolts fitted tightl and read for marking/drilling the outside mounting bolts. o keep e er thing at for the holes to be transferred/ drilled I bolted the reverser base to the stool ready for marking out the holes. It was here that I discovered an error that had made when fitting the

Model Engineer 17 May 2024

FLYING SCOTSMAN

10

Trial fit of the reverser on the stool.

13

11

12

A point on a 6BA bolt to make locating the bolt a little easier.

14

First three bolts fitted ready for marking and drilling the other side.

15

Accidental misalignment of fixing holes.

Marking the positions of the outside mounting holes. reverser base to the stool. I had placed the base directly on the stool but, actually, it’s offset to the outside. I only noticed this when checking the fit with the base doubler bolted to its base.

No big deal - I just needed to redrill/tap the offending holes but an annoying delay nonetheless. Photograph 13, with the doubler plate held, shows the problem - there needs to be a gap matching the thickness of the frames.

Before taking the base off I first transferred where the holes should be and then marked the frames down from the top edge 9/32 inch for where the outside holes need to be drilled (photo 14 chose to mark where the holes would best be avoiding the spring guards which Don left off his drawings.

I hate drilling into painted parts but if needs be, I’ll have some tidying up to do later. fter drilling a hole placed a spare drill to keep things in place while drilling by hand (photo 15

www.model-engineer.co.uk

Drilling the outside mounting holes.

16

The reverser base mounted on the stool.

Photograph 16 shows the reverser base on its stool which is securely mounted and sandwiched between the mainframes and trailing frames.

To quote the great Don Young: ‘The stand will test both our resolve and patience’. That may be so but then you add nutter’s like me, and many of

you other builders out there who add extra detail to the equation, that at times can test the patience of a saint, I suspect that the reverser will be such an item n wa on with the craziness.

Before getting to brazing the reverser assembly together first needed to decide on how the base would meet the cab oor wo options carefull cut the oor around the base or mount through it.

Cutting around the reverser might make removing the cab oor easier but to do that ou d first ha e to remo e a lot more parts anyway, and it would also leave the front right-hand corner unsupported, so not an option o do plot the holes with precision or do I make life easier, and cut large slots or even remove the middle section entirely? Don states that the reverser on the prototype was very stiff.

Fellow builders of Gresley acifics ha e also warned me

671

>>

17

18

Marking out the floor for accommodating the reverser stool.

19

Clearance slots for the reverser mounting bolts.

20

22

Shelf in its open position.

A simple modification to achieve a hinged shelf.

21

Shelf in its closed position.

672

of this so I will not remove the middle section but cut slots so that the reverser base has more support underneath.

The reason for choosing slots over slightly larger holes for clearance is purely a ‘just in case’ scenario where I might, for some reason, need to work on something on the ou know, when at the track with limited resources.

Enough rambling - on to the job at hand. Before cutting an thing lined up the oor and marked approximately where to start machining fter taking a few measurements I marked

where the hole in the top right centre of the base will be (not the doubler and photo 17 shows where I will set the DRO to zero when held in the machine vice. fter chain drilling rows of holes I used an endmill cutter perhaps a little too large to create slots which gave me far more clearance than I should ever need (photo 18 reverser now has a gear gate…

Do you recall me mentioning a cunning plan for following the prototype more closely but still being able to get access to the mounting bolts? Well, I plan to have the shelf, that sits above

The full-sized reverser showing the shelf (lower left of the photograph). the bolts, hinged so I can get at them. Photograph 19 shows this shelf, which also has a front shield to it. I’ll add that later along with other parts.

This photograph is also useful for something else although not just yet - it just happens to show the indicator arm still attached giving a good idea of its angle and height. This information will become handy er soon modification (photo 20 simpl in ol es filing the shelf fitting tabs round so that the shelf becomes hinged - simple. then did a test fit of the assembly so far. Here the shelf is seen in its lowered position (photo 21 lso clear here is that the washout plug will need the re erser remo ed first for access to be able to clean this corner of the boiler - not really a problem as such an operation won’t be done that often. nd here photo 22 show the shelf raised with a box spanner on one of the more difficult bolts to reach it would be too difficult to reach with the shelf fi ed ote some s had the reverser on the left and some on the right. The set of laser cut parts can of course be assembled with either handedness.

To be continued.

Model Engineer 17 May 2024

Llanelli’s Spring Rally John Arrowsmith takes a trip to North Wales and a busy spring rally, blessed wit fine weat er.

www.model-engineer.co.uk

his well-established event in the model engineer’s calendar was held at the Pembrey Park site of the Llanelli and District Model Engineers. The weather forecast for the weekend was not encouraging but, as often is the case, after early morning rain on Saturday the remainder of the weekend en o ed some fine sunshine and dry days. The wind was a bit sharp at times but as is the way with true model engineers, everyone just got on with enjoying themselves. Rob Rayner and his fellow members had organised a wide variety of both locomotives and traction engines to take part. The great thing about the location is that the whole area was once a MoD Munitions facility so there is plenty of hard standing and surfaced roads, which means the traction engines and steam lorries were able to make full use of these surfaces. The park itself is large and is open to the general public which ensures there are always plenty of passengers for the railway. In addition, of course, it is adjacent to the lovely beaches of this part of South Wales which is also another attraction. I did take a stroll to the beach which looked superb in the sunshine and the walk really blew the cobwebs away.

Onto the rally itself; it was just getting into its stride by the time I got there, with the busy atmosphere of engines being prepared for work both on the track and the roads. The multigauge 7¼ and 5 inch gauge ground level track extends for about 2/3 mile through tall pines and the usual coastal foliage and is very well laid out with testing gradients to catch out the inexperienced driver.

The ground level in the station area is approximately 2 metres lower than the track on the far side of the route, at Briary Hill

T

Halt, so you can see what I mean about testing gradients.

This railway is supplemented with a multi-gauge raised track of 3½ and 5 inch gauges of approx 1/3 mile in length. This track also has a nice curved tunnel which emerges just below the summit which, again, catches some drivers out as it appears to be level in the tunnel but is, in fact, still on a rising gradient. The track does not have the steep gradient of the main line so it is easier to drive smaller locomotives without difficult The main station is a short distance from the steaming bays so that spectators in the park can see the preparations without impacting the queue for rides. They can also see the engines backing down from the ‘shed’ to pick up their train in the station, which is a good crowd pleaser. The ground level track runs in a clockwise direction with the inner raised track running anti-clockwise; this adds to the passengers enjoyment, seeing passing trains during their journey. The club have a couple of powerful battery and petrol locomotives for these occasions and with

six heavy carriages to pull, plus passengers, they earn their keep. These trains were mixed with a variety of 7¼ inch gauge steam locomotives that were also pulling fi e coaches at times.

On the roadways outside the club’s perimeter fence, the steam road vehicles were busy as well and that lovely familiar atmosphere of steam and hot oil was soon engulfing the spectators. I had a good feeling walking around the different engines being prepared and I was greeted with a good humoured response to questions requesting information about the drivers and their engines. One in particular I found delightful; a driver told me that steam road vehicles always have a mate with them who has to be registered with the vehicle when it arrives. In this case the mate’s name was Bob. I enquired what Bob was doing and the reply was … “ask him!”

I turned to see a lovely Beagle curled up on a comfy chair with two soulful eyes watching my every move (photo 1)! The oden steam lorr was a fine model and was owned by Phil

1

>>

Phil Weston’s lorry’s ‘mate’ - Bob the Beagle.

673

2

3

Another view of Peter’s lorry with the additional water tanks on the side of the flat bed.

Phil Weston with his Foden Steam Lorry.

4

5

The steam up begins with the club secretary and chaplain, Jim Flanagan and son Thomas steaming their LNER tank engine.

Built in six months by a blacksmith without drawings was this 6 inch freelance traction engine owned by Ray Wallace.

7

6

Joel looks happy with his track time.

John Carrol with his 5 inch gauge Manor preparing his engine for the day.

Weston (photo 2). Phil had modified the rear lorr oor b adding two additional water tanks on either side. This had changed the appearance of the

674

model but also provided him with extra capacity and weight on the wheels (photo 3). There were some interesting stories to be heard and seen. The

6 inch scale traction engine owned by Ray Wallace is a case in point, as this engine was built by a blacksmith in the Shetland Isles over a six month period - without any drawings!

Ray has owned the engine for 15 years and it is still going well (photo 4).

It was also good to see the young engineers from the club involved with the

Model Engineer 17 May 2024

LLANELLI

8

9

Joe Hockley takes his family for a ride on the raised track.

Young member Jacob starts the powerful A2 away from the station with his family as passengers.

11

10

John Williams concentrates on the road ahead as he powers Heilan Lassie around the raised track.

Paul Pavier showing this young visitor the workings of his steam lorry. day’s operations. Driving on both the raised track and the ground level system, all of them displayed composure and confidence in dri ing the available locomotives. he first oung man talked to was Thomas Flanagan who is the son of the club’s secretary and chaplain, Jim Flanagan. Together they were preparing their small 5 inch gauge 0-6-0 LNER tank engine for use on the raised track. It was an engine they had bought but which needed some work to become a reliable locomotive (photo 5).

They soon had it in steam and enjoyed their time on the track where it performed very well.

Whilst they had been working on the steam locomotive, Thomas built a 7¼ inch gauge

www.model-engineer.co.uk

Scamp which was recognised by the 7¼ Inch Gauge Society which awarded Thomas a ighl ommended certificate for his efforts. This augurs well for his future as a good model engineer with the club.

Another good looking locomotive was also being steamed at the same time; a 5 inch gauge GWR Manor 7828 Odney Manor. This engine is now owned by John Carrol who was in the process of learning the best way to drive it (photo ). He is also a member of the Cardiff club.

Two other young members of the club were also enjoying themselves on the track, both with individual engines and then double heading. Jacob and Joel (photo 7) were keen to talk about their involvement

with the club. Jacob was also driving a large 7¼ inch gauge LNER A2 during the day, with all the skill of a seasoned driver (photo 8). With passenger trains in constant demand, it was good to see the raised track being used by both electric and steam locomotives. Joe also enjoyed taking his family for a drive and I think the smiles on their faces say it all (photo 9). It was also good to see how the senior members and visitors interacted with the youngsters during the weekend, helping whenever they could and, in one case, I found Paul Pavier lying across the bed of his steam lorry explaining in detail to a visitor how everything worked. Watched by his mum, this young man showed some real interest in what Paul was saying (photo 10). Perhaps

this little chat will inspire the young fellow to get involved and maybe even pursue a long career in mechanical engineering!

During the weekend there was some spirited running on the raised track with a range of 3½ inch gauge locomotives being put through their paces in some style. John Williams from the Southport club was driving an LBSC design version of Heilan Lassie but, unlike the original, this engine had Baker valve gear and it was absolutel ing around the circuit at some speed, lap after lap (photo 11). My camera has stopped the motion but I can assure you that engine was moving very quickly. Another small engine that was making very light work of the track for a number of hours during the day was a little 3½ inch 0-6-0

675

>>

12

13

Pete Lawson with his K2 takes the train away from the station area out into the country.

Tom Taylor tends the F s fire during a stop at the raised track station.

LMS 4F driven by Tom Taylor (photo 12). This locomotive’s motion was just a blur when it was going. However, not to be outdone by these little engines a 3½ inch gauge Southern Q class 0-6-0, driven by Danny Hayworth, was also making a name for itself with a similar

performance. I had a ride behind Tom and the 4F and my extra weight didn’t seem to reduce the performance one iota. It still just buzzed around the track with consummate ease.

As I mentioned above there was a good selection of 7¼

inch gauge locomotives, both home club engines and visitors.

All took turns at some time during the weekend in hauling passenger trains, but the bulk of the work was done by a visiting LNER K2 locomotive owned by Pete Lawson. This 2-6-0 Mogul worked very well for long periods (photo 13) and, along with the club’s own electric engine working very hard, provided a continuous service (photo 14). Chris

Wilson from the Vale of Aylesbury club had brought his superb example of a GWR Armstrong/Gooch 4-4-0 to enjoy some track time. This beautifull finished locomoti e went as well as it looked and climbing the 1:45/50 incline really made the crisp valve setting stand out (photo 15). nother fine looking engine in steam and operating for long periods was a rarely seen model of an LNER A2. Built

14

The club’s electric engine waits to leave the station with visitors from the Swanley Barn Railway as passengers.

676

Model Engineer 17 May 2024

LLANELLI

15

16

The 7¼ inch gauge A2 starts the climb to the summit with plenty of steam.

Chris Wilson with his locomotive waits departure from the station.

18

17

Double motive power as the 1500 tanks work together around the circuit.

19

The club’s disability train in action during the weekend.

Father and son, Gareth and Andrew Williams have the Sweet William going well as it departs the station. some years ago to work for the Walsall Model Railway Society, they had it for about 20 years before it went into private hands. Colin Palin from Nottingham has had it for about six months. This is the engine that young club member, Jacob was handling like a seasoned model engineer (photo 1 ). A father and son duo, Andrew and Gareth Williams were driving a very good looking Sweet William 0-4-2; both are members of the

www.model-engineer.co.uk

Pembroke Model Engineers and were enjoying their time on the track (photo 17).

Two 15XX tank locomotives owned respectively by Bob Thompson and Mike Pearce, both members of the Salisbury club, were also doing sterling work during the weekend and combined to double-head their train which provided a powerful combination. They had no trouble with the track gradients (photo 18 ne final train was that which contained

the disability car. This vehicle can accommodate both a wheelchair and a couple of passengers so that almost any disability can be catered for. It was used a number of times during the weekend giving rides to people who without it could not have enjoyed a ride on the train (photo 19).

It was a most enjoyable weekend with plenty of good natured banter and hospitality.

Guests were well fed and watered by two excellent vendors supplied by the country park. There was a continuous supply of tea and coffee available from the club which kept the drivers and club visitors happy.

Overall, the event was a happy time, enjoyed by everyone, with good weather and some excellent operating by the club and their visitors - and also by the general public who contributed to the overall atmosphere of the weekend. My thanks as usual to Rob Rayner and all the members of the Llanelli club who organised the event and to all the people I spoke to for their warmth and help with information. The weekend was a shining example of what can be achieved in these days of national doom and gloom.

Thank you all.

ME

677

Oscillating Engine Design Martin Gearing explores different approaches to the design of oscillators.

read David Fulton’s article in Model Engineer (ref 1) on the background to the design of his very neat looking ‘Forerunner’ oscillating engine and was struck that his method described in the ‘Moving Diagram’ section would be able to overcome the error in geometry of the drawing shown in fig for the setting out of the porting in an oscillating

I

engine attributed to Greenly and arris owe er the difference between the two methods in actual geometry of the port positions wasn’t highlighted and ha ing seen the two items a beginner might be confused making for a high chance they would miss a golden opportunity when building an engine of this genre from scratch. Although the

PART 1 engine will doubtless run when finished sadl it will not be as good as it could/should be!

The underlying design considerations of the group of engines with ‘oscillating’ (or ‘wobbling’ - the term used on the other side of the ‘pond’) cylinders are generally overlooked or perhaps overshadowed by the fact that it is most commonly seen in

1

Wapiti, a 5-inch gauge locomotive with oscillating cylinders.

678

Model Engineer 17 May 2024

OSCILLATORS

use as the power source for the cheaper end models better described as to s where the were usually of the simplest single acting form. hat being so there can be very few people that would not actually be able to recognise one and as is often the case with commonplace things few people actually take a great deal of interest in the detail. first encounter as a child was with a little vertical double acting Stuart Turner single that had initially seen life inside a steam powered model boat before passing through several owners’ hands and then arriving in mine. By that time the threads securing the lower cylinder cover had been stripped but this had been overcome by soft soldering the two parts together. The gland nut thread had worn so badly that the nut presumably wouldn’t remain in place so that had been removed leaving the engine without a piston rod gland of any sort. These features did nothing to detract from the fact that it had been given to me and was therefore m first engine Various sources and varieties of invisible gas were used to power the engine which I won’t describe suffice it to sa that it never experienced steam until man ears later when the need for the missing gland to be replaced in some form was displayed beyond doubt!

Looking at various old texts of commercial oscillating engines (in the same way as hot air engines the seem to have had a brief period of popularity for installations requiring some cheap simple means of rotation - until both were displaced by the electric motor as electrical supply became available. The one place they were suited to was in e plosi e atmospheres usually running on air until replaced by the more advanced designs as industry hunger for power grew more voracious.

There were exceptions howe er such as powering sea going ships and as disco ered later also full si e industrial railway locomotives.

www.model-engineer.co.uk

One example of this came in the form of a 5-inch gauge (2½ inch scale) locomotive at Andover Model Engineering ociet called Wapiti that had run very successfully for in excess of 50 years before the boiler recently failed due to corrosion.

Wapiti had been built by Gordon Howell (ref 1 a dynamic founder member of the club after he’d experienced driving Reg Dimmer’s oscillating cylinder locomotive at Durrington.

Gordon asked Reg to design something similar for him. rom what can disco er Wapiti would appear to be a fairl true cop of a full si e inch gauge ton locomoti e typically built by Dewey rothers of enter treet oldsboro orth arolina America.

This company was formed in b harles assisted by his brothers George W. and rnest ewe taking over a former business. Due to the growth in the area the company built between and se eral small industrial locomotives around tons mostl or configuration powered b oscillating cylinders directly connected to the wheels describing them as a ‘Four Wheel Connected Locomotive’.

These used the conventional cylinder pivot placement in the mid bore position with the ports on a at side face Production of this type of locomotive stopped about the same time as the company introduced its new geared type. nother compan iler tower of ilwaukee made similar si e locomoti es BUT with the whole cylinder containing the piston and rod assembl ha ing an e e cast integral with it swinging about a trunnion fi ed across the frame containing the required porting. Both companies supplied the engines mainly to the lumber industry.

Wapiti was built by Gordon in fifteen months ha ing two inch bore b inch stroke cylinders and small wheels which with the 90 psi boiler

gave it a reputation of being able to ‘pull a house down’! n its first steaming after ‘debugging’ with Reg Wilkins ilkie as he is also known and still a club member) as test dri er it did laps non stop miles to pro e its worth fter ears the steel fire tubes were replaced with copper (photo 1).

Gordon is probably remembered for his eet of oscillating engine powered models including a inch bore by 2 inch stroke engine powering a six wheel Atkinson truck that ran on pneumatics After that Gordon built another this time a 2 x 2 inch compound oscillating engine using it to power a four wheel orkshire steam tractor also on pneumatics. t ears of age he then produced a oad ailer as a compromise feeling he d ‘…not enough time left to make a proper 7¼ inch gauge loco’. by adapting the Yorkshire road tractor as the power unit within a entinel t pe shunter loosel based on the form of an 0–6–0 built for the omba aroda entral ndia ailwa s removing the wheels from the road tractor it could be lowered onto the locomotive chassis and then run on 7¼ inch tracks.

This engine successfully ran at man locations e ents running for the morning in the oad ractor configuration and the afternoon in the ‘Sentinel hunter configuration on the track at Guildford. Another

Fig 1

time at a Southampton track celebration it was mentioned in a review by Ted Joliffe in Model Engineer ( ).

Gordon later made the comment ‘This may not be everybody’s idea of a 7¼ inch gauge loco but ha e had a lot of fun and enjoyed many interesting conversations!’.

Handsome looking examples of oscillating/wobbler engines are still being designed and built. One such example seen recently was in an excellent series of six articles on the building of a good-looking hori ontal twin double acting engine in Live Steam & Outdoor Railroad by Pat Jorgensen and Ken Kroeker (ref 3).

I was struck by the brilliant method of achieving the exhaust and inlet ports by radial milling of the fi ed face port block rather than by the conventional method of plugged drilled holes as demanded by a double acting oscillating cylinder ( 1). gain in the bar stock interpretation of the same basic design as the Green Twin by James Donnelly ( 4) made to m e e a neater arrangement by having the two circular port faces facing inboard.

The downside to the radial port method was that it significantl adds to the force needed to keep the port faces in contact/sealed because of the increased area under suppl pressure owe er if a thin sandwich plate with only

Bearing block having radially milled inlet & exhaust cavities connecting upper & lower port locations

Conventionally ported cylinder

Fig.1. Oscillating Engine Porting As Used On Green Twin >>

Green Twin - radially milled ports.

679

Fig 2

3

Ported plate - when attached to the ‘manifold’/bearing block, by reducing the surface area exposed to pressure of the working gas, reduces the force required to seal the port faces

Fig.2. Oscillating Engine Porting Plate Oscillating engine - porting plate. the required port hole drillings is secured over the radial slots of the fi ed face it gi es the best of both worlds – ease of manufacture and retaining the very neat circular appearance ( ).

Use of a solid thrust washer n the same sub ect ha e found the conventional method of using a spring to provide the force (often unnecessarily excessive) that is required

Wooden oscillating engine.

2

Traction engine with an oscillating cylinder.

to maintain a seal of the port faces as used in the ames onnelle bar stock ersion would be better replaced by the use of either a Nylock or pair of lock nuts against a thrust washer as used in the earlier original cast version of Green Twin by Pat Jorgensen and Ken Kroeker. This will almost certainly allow the bar stock engine to run with less friction and hence a greater efficienc Just to prove that nothing is new I stumbled across this method described in a design of an oscillating feed pump by ETW (Edgar T Westbury)! (ref 5) The proof of this design came about when I explored methods of reducing unnecessary friction in what is best described as oscillating engines of ‘Limited Power’. The first was in the form of a small model traction engine powered b compressed air intended for operation by young children

680

Model Engineer 17 May 2024