Thursday 17 September 2020

Locomotive Profile: Great Western '4575' Class

The influence of George Jackson Churchward (1857-1933) on the history of the Great Western Railway (GWR) was immense. Churchward was assistant to the revered William Dean (1840-1905), Chief Locomotive Engineer of the GWR, for a number of years and in that time he had started to formulate his own policies for equipping the GWR with the finest motive power possible, based on a few standard classes using scientific design principles. When Dean retired in 1902, Churchward became Chief Mechanical Engineer of the GWR, serving in that role until 1922. In a flurry of activity after he took over, Churchward laid down the template for locomotive design which served the GWR until the end of steam locomotive design in the UK.

In 1903, 4-6-0 locomotive number 98 emerged from Swindon works representing the first of his standard designs. It featured two outside cylinders with 10-inch piston valves and represented a maturing of ideas incorporated in 4-6-0 number 100 built the previous year. Two other prototypes for standard designs emerged in 1903, again with two outside cylinders and piston valves - a freight 2-8-0 locomotive number 97 which was the forerunner of the famous '28XX' class and a large-wheeled 2-6-2 tank number 99. Significantly, in a triumph of the foundrymans' art, in all three designs, one cylinder, its valve chest, associated internal passages and half the saddle to support a 'drumhead' smokebox were combined in a single casting. In each case, two castings bolted together on the centreline of the locomotive formed the complete 2-cylinder 'engine'.

Churchward had a cautious approach and these prototypes were intended to run for a couple of years to prove the soundness of the design before further orders were placed but motive power needs meant that a small-wheel version of the 2-6-2 tank, number 115, appeared in 1904 and its success in the West Country and Wales led to ten further locomotives (numbered 3101-3110) being built in Wolverhampton works in 1905-1906. Number 115 was eventually renumbered 4400 and the ten later locomotives 4401-4410.

Further experience suggested an increase in driving wheel diameter would be helpful and twenty more 'Light Prairies' were built at Wolverhampton with 4 feet 7½ inch diameter wheels, with more to follow built at Swindon. Various modifications were introduced to these popular engines - top feed, an extended smokebox, superheaters with boiler pressure raised from 180 p.s.i. to 200 p.s.i. and an extended coal bunker bringing the weight up to around 56 tons 13 cwt. Cylinders were 16½ x 24 inch. 

Preserved locomotive 5542 of the '4575' class has proved popular with both visitors and crews on her various lisits to the Battlefield Line. The Wikipedia article on this locomotive says:-
In 1904 G J. Churchward introduced the 2-6-2T locomotive No 115 that was to be the forerunner of the 45xx class locomotives. The prototype, built at Swindon, very quickly proved most useful, and a further 10 examples were soon constructed at Wolverhampton locomotive works. The new locos sported copper topped chimneys and were originally numbered in the 31xx series but were re-numbered as the 44xx class. They were well equipped for use on the steep and twisting Great Western branch lines, particularly in and around the West Country. They were noted for excellent acceleration but with 4ft 1½in wheels their speed was restricted. Various modifications were soon introduced amongst other things, increased coal capacity, superheated boilers with increased pressure, at that time 180 p.s.i, and greater cylinder capacity.

Locomotive 5526 (also a member of the '4575' class) has proved equally popular on her visits to the Battlefield Line. 

References

[ 1] ‘A Pictorial Record of Great Western Engines’ by J. H. Russell (Oxford Publishing Company Vol. 1 & 2 1975: reprinted as one volume 1978) SBN 0 86093 02 6.
[ 2] ‘Great Western Steam’ by W. A. Tuplin (George Allen and Unwin 1958).

Related posts on other websites

GWR 4575 Class (Wikipedia)
GWR 4575 Class 5542 (Wikipedia)

Related posts on this website

The following posts talk about members of the '4575' class:-

'Cold Turkey Gala' at the Battlefield Line (5526 & 5542)
Preparing 5542 (part 2) 
3 Sep 2018
5542 at the Battlefield Line 28 Aug 2018
More Fish and Chips 15 Jul 2018
Santa Specials at the Battlefield Line 2017 19 Dec 2017
On the Footplate 5 Dec 2017
GWR 'Light Prairie' 5542 22 Aug 2010

My photograph albums

Where necessary, clicking on an image above will display an 'uncropped' view or, alternately, pictures may be selected, viewed or downloaded, in various sizes, from the albums listed:-

5526 GWR Locomotive
5542 GWR Locomotive
5521 GWR Locomotive
5553 G.W.R. Locomotive
4588 G.W.R. Locomotive


Aerobatic Experience

I love flying. Although I've enjoyed a few flying lessons over the years, I decided that it would be too expensive and take more commitment than I was prepared to give to learn to fly an aircraft. But I'm always happy to be taken aloft by a qualified pilot. Only once, though, have I had an aerobatic flight. My friend Jack Upchurch, sadly now passed on, was a passionate aerobatic pilot of competition standard, flying a Stampe bi-plane or a tiny 'Turbulent' monoplane. Some years ago, I accompanied Jack and his wife Rita to Headcorn airfield where the aircraft he flew were based. There was a flying 'slot' available on the Stampe, registration G-AWEF, and Jack invited me to accompany him on a short, local flight. Up close, the Stampe looked very small and fragile. It's a two-seat aircraft: the pilot is at the rear and the passenger (or trainee) in front, each in their own small cockpit.


Jack and Jan chatting before the flight (Photo: Rita Upchurch)

As instructed, I stepped carefully onto the lower wing and levered myself into the front seat.


Jan in the front seat before the flight (Photo: Rita Upchurch)

Jack followed into the pilot's seat, wearing flying overalls and World War II leather flying helmet incorporating earphones and facemask with microphone, with the cable held in his mouth, presumably to prevent it from becoming trapped as he sat in the restricted space.

Jack boarding the cockpit (with headset lead held in his mouth) before the flight (Photo: Rita Upchurch)

The gentleman serving as ground crew arrived with the 5-point safety harness, trussed me into position and supplied me with a modern version of the flying helmet with miniature earphones and a boom microphone.


Ground crew arranging Jan's harness and headset before the flight (Photo: Rita Upchurch)

Once the headsets were plugged into their jacks, there was two-way speech between Jack and I.


Jack and Jan before the flight (Photo: Rita Upchurch)

The Stampe has open cockpits, with a small windscreen in front of each to give some protection from the airflow. The ground crew carried out the final checks before closing the hinged access flaps on each side of the cockpit which had been lowered to allow access on the ground. When raised and latched, they offer some protection from the airflow.


Ground crew carrying out final checks before the flight (Photo: Rita Upchurch)

Checks complete, the De Haviland Gipsy Major 10 engine was started and Jack taxied the aircraft to the grass runway 10/28. The take off run was a little bumpy on grass but what impressed me, more used to larger jet aircraft, was how quickly the aircraft seemed to float off the ground without effort. As Jack climbed away from the runway, I was expecting a sightseeing trip. When one wing dipped to point to the ground, it seemed a good way to admire the countryside - the view ahead in level flight didn't show much of the ground. But, with increasing horror, I realised that Jack was continuing the roll so that my harness suddenly tightened as the seat, unaided by gravity, failed to support me as we flew inverted. I experienced terror as I realised that the five straps of my harness were all that prevented me from plunging to earth. Jack rolled the aircraft right way up and immediately started a steep climb which again involved being inverted at the top of the loop.

After the flight, I discovered that Jack was executing a standard series of what he called 'simple' aerobatic manoeuvres, accurately timed and positioned in a three-dimensional 'box'. But at the time, the assault on my senses was almost overwhelming and I started to feel sick. I think it was only the humiliating thought of actually throwing-up in the aircraft (no sick bags were provided) which allowed me to control the urge. I considered using the intercom to ask Jack to stop but my curious thought was 'if he stops now, I'll never have the confidence to attempt it again, so I'd better keep quiet'. On the rare occasions Jack spoke to me on the intercom, I somehow managed to reply in a fairly normal voice, suppressing my feeling of panic. I have no clear recollection of the various manoeuvres Jack executed but new (and unwelcome) sensations kept occuring as we moved through the programme. I remember at one point Jack saying "There's Leeds Castle" (about six miles from Headcorn) and dropping a wing to give a better view. I don't think the manoeuvres lasted long before we entered a period of 'staight and level' flight. At first, I was very relieved but I soon started to think how boring it was, compared with the preceding excitement which had so terrified me. We were soon back at Headcorn and made a gentle landing.


Pilot's view on approach to Runway 28 at Headcorn (from Headcorn Aerodrome website)

When the engine stopped, I felt completely disorientated. Getting into the aircraft hadn't been easy but getting out almost defeated me. Once I was finally back on the grass, my sense of balance had almost deserted me and for some minutes I staggered about as if inebriated. My deception on the intercom had been convincing and Jack said he had no idea of the terrors I had experienced. After a few more minutes, I felt completely recovered and found myself saying "When can we go again?". Jack checked on the bookings for the rest of the day, but there was no availability and, to date, that remains my only aerobatic flight.


Map of Headcorn Aerodrome, ICAO designator EGKH (from Headcorn Aerodrome website)

The Stampe SV.4 Aircraft

The Stampe SV.4 was a Belgian design in 1933 by George Ivanov for Stampe et Vertongen of Antwerp as a tourer and trainer. 35 aircraft were built before closure prior to World War II. Post-war, successors Stampe et Renard built a further 65 plus 940 built under license by SNCAN in France and an Algerian firm. There's a Wikipedia article on Stampe here

The aircraft I flew in is a post-war model SV.4C

Engines used on Stampe aircraft

The Stampe SV.4 uses a 4-cylinder, air-cooled in-line inverted aero engine. For aircraft use, the engine crankshaft must be high enough off the ground to give the propellor clearance under all conditions. In a inverted engine, the cylinders are placed underneath the crankshaft, allowing the pilot an unobstructed view ahead. Renault engines were commonly used but the De Haviland Gipsy Major was also used.

I believe the aircraft I flew in is equipped with Gipsy Magor 10 Mark I.There's an article on the Gipsy Major engine here.

Pictures
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