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The Vanwall Grand Prix engines
Part 4: The 2.5-litre F1 engine

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Who?

Mike Hawthorn

What?

Vanwall VW1

Where?

Monaco

When?

XIII Monaco GP (May 22, 1955)

 Mike Hawthorn, Vanwall, 1955 Monaco GP
Why?

In late 1953, while development of the 2-litre engine progressed, Fox and his team started work on the design and build of the 2.5-litre engine for use in the new Formula 1 starting in 1954 and parts were being ordered. The 2.5-litre engine had the same structural arrangement of components as the 2-litre one but virtually every major part required re-design or change to accommodate the increased capacity and incorporate new thoughts on design.

Cores and patterns of the RR B40 crankcase/cylinder block were again borrowed from Leyland Motors, to enable VP to produce a new crankcase with increased cylinder centre spacing. Into 1954, Fox and Richter worked closely with Norton's Leo Kuzmicki, who was designing key aspects of the cylinder head (camshafts, valves, ports and combustion chamber) for the 2.5-litre engine. The Norton Motors racing department was being run down by the new owners and by late 1954, Kuzmicki would leave Norton and join VP as a research engineer working on Vanwall engine development.

The 2.5-litre engine was naturally still a 4-cylinder in-line design, but with a bore of 96mm combined with the original stroke of 86mm, for a swept volume of 2490cc. The biggest change from the earlier 2-litre engine was the adoption of a 5 main bearing crankshaft and a new cylinder head with a reduced valve included angle. The completed engine was 63.7cm (25”) tall from the top edges of the cam boxes to the sump plates.

Parts were being ordered initially to build two engines, and the key changes from the 2-litre/2.3-litre engines are detailed below.

4.1 Crankcase

To accommodate the bigger bore of 96mm, the cylinder centre spacing had to be increased, so VP produced new cores and patterns to enable new crankcases to be cast which also incorporated the 5 main bearing support of the source B40 unit. Otherwise, the crankcase was similarly proportioned to those used on the first 2-litre/2.3-litre engines, with the same deep skirts extending 65mm below the crankshaft centreline and thick top support for the cylinder barrels; the crankcase casting was 20.6cm deep from top to bottom. Early in 1954 an order was again placed with Aeroplane and Motor Aluminium Castings Ltd. for the new crankcases to be cast in RR53B aluminium alloy.

4.2 Crankshaft

The crankshaft was re-designed to now have five main bearings (as in the RR B40 engine on which it was based) and with wider crankpin spacing to match the increased cylinder centre spacing. There were counterbalance weights on webs 1 ,4 ,5 and 8 which counteracted 87% of the total bending effect produced by the purely rotating parts of the engine, including the rotating weight of the connecting rods (ref. Proc. Instn. Mech. Engrs. [AD] no.2 1958-59). The crank throw was 43mm and the crank webs were 20mm thick.

The same bearing sizes were used as before, 69.9mm diameter main bearing journals and 50.8mm diameter crankpin journals, while the centre and rear main bearings were wider than the others (scaling from photographs, they measured 47.3mm wide while the second and fourth bearings measured 43.5mm wide and the front one 38.9mm wide, the crankpins measured 32.2mm wide). The thrust washer was on the centre main journal. The main bearing caps were very deep and extended down level with the crankcase bottom face, the front and rear caps were located securely within the ends of the crankcase casting, and the feet of the intermediate main bearing caps were set 14mm into their respective crankcase supports.

In early 1954, the crankshafts were ordered from the other arm of Smiths Stampings, Smith-Clayton Forge of Lincoln, to be forged in 1% chrome molybdenum EN19 steel and then on to Laystall Engineering for machining and balancing. Again, surface treatment of the bearing surfaces was carried out by VP.

4.3 Cylinders and Reciprocating Parts

At the end of 1953, Fox ordered eight new cylinder barrels, again from Wellworthy Ltd. in the same spec DTD 485 cast iron as before but with a bore of 96mm. They would be deeply spigoted into the crankcase and also into the cylinder head, exactly as in the 2-litre and 2.3-litre engines.

At the same time, High Duty Alloys were forging new piston blanks of 100mm diameter from which the required 96mm bore pistons could be machined by Hepworth & Grandage. The pistons were still slipper-type with the same ring arrangement as before, but the crown was re-modelled by Kuzmicki, particularly to provide moderate 'squish' areas with the combustion chambers in the revised cylinder head being produced for the 2.5-litre engine.

The connecting rods and gudgeon pins were the same as before.

4.4 Cylinder Head and Valve Gear

With the larger cylinder bore, a decision was made to reduce the valve included angle so as to retain a favourable surface to volume ratio for the combustion chamber. A new cylinder head was designed to accommodate all the necessary changes while still retaining the structural arrangement of the earlier one.

The inlet and exhaust valves were symmetrically inclined at a valve included angle of 60°. The inlet valves were 50mm in diameter and the exhaust valves 43.7mm in diameter. The port shapes and angles still mirrored Norton practice with the inlet ports angled in plan 75° to the engine centreline, to promote swirl in the combustion chamber .The inlet ports also retained the 20° downdraft angle to the horizontal so the total inlet flow angle to the cylinder axis in the transverse plane was again 70°. The inner curve of the port at its junction with the valve seat was not parallel to the valve axis but was at an angle of 20° to it, still insufficient to create any meaningful 'barrel' turbulence, even with the smaller VIA.

The valve operating gear and dual hairpin valve springs were exactly the same as the works Norton “500” and as previously described in part 1.4 for the 2-litre engine.

Typical valve timing was:

Inlet opens 70° BTDC Inlet closes 90° ABDC
Exhaust opens 75° BBDC Exhaust closes 49° ATDC
Valve overlap period 119°

The gear drive to the camshafts was from a similar but suitably modified primary gear case while the secondary gear case on its front drove the magneto by a direct shaft offtake and the fuel pump as before.

The cylinder head castings were again ordered from Aeroplane and Motor Aluminium Castings Ltd in RR50 aluminium alloy and as before they were quite shallow.

4.5 Carburation

The first 2.5-litre engine was equipped with the same 4 Amal carburettor set-up as used on the previous 2-litre and 2.3-litre engines. By this time, Fox and his team had settled on using S.U. float chambers, as they were better able to cope with the engines vibrations.

But Vandervell was intent on using fuel injection and was working in conjunction with Robert Bosch to develop a system for his engine and mid-year he went to Stuttgart to spend time with Bosch and Daimler Benz where Rudi Uhlenhaut was very helpful revealing details of their experience of high-pressure direct fuel injection. Vandervell, though, had decided on port fuel injection for his engine. Originally, it was intended to use a combination of two of the twin-cylinder production pumps used on the German Goliath car engine but that idea had been dropped and Bosch were making a special four-cylinder injection pump specifically for the Vanwall engine. But it would not be fitted before the first 2.5-litre engine was used in the Vanwall Special.

4.6 Exhaust, Ignition, Lubrication and Cooling System

These systems were exactly as used on the 2.3-litre engine, in particular the use of the special double-bodied B.T.H. magneto. After the Goodwood Trophy race in September, a conventional oil cooler was fitted in the nose (see part 1.8).

4.7 Race Performance and Development 2.5-litre 1954

The 2.5-litre engine (the third engine built) was complete and running on the dynamometer at Maidenhead by August 1954 and it was showing promise; so Vandervell planned to use it in an entry for the Italian GP, to be run early in September. But as already detailed, the engine dropped a valve during endurance testing which caused considerable damage and the 2.3-litre engine had to be used instead.

The 2.5-litre engine was rebuilt and installed in the Vanwall Special in time for the Goodwood Trophy on 25 September. Collins drove and finished second to Moss in a Maserati 250F in the F1 race and Vandervell was very satisfied with the engine's performance, although the extra power showed that the chassis needed more work. Mike Hawthorn drove the car in the Formula Libre race and finished fourth.

Then on 2 October, the 2.5-litre was entered in the Daily Telegraph Trophy at Aintree where it was second in the F1 race but retired in the F Libre race after Hawthorn spun and got dirt in the nose oil cooler causing overheating. After the two drives, Hawthorn commented that at Goodwood the real power didn't come in until about 4,500rpm but above that it was quite fast, while at Aintree he found the engine seemed fluffy over 7,000rpm, possibly due to fuel starvation, he thought.

Vandervell wanted to see the car's international potential so an entry was made in the Spanish GP to be held on 24 October. Before then, the 2.5-litre engine was extensively tested by Arthur Pratt (head of testing at Maidenhead), trying different fuels and various grades of hairpin valve springs which were giving problems with breakages. The chief engineer of spring maker George Slater & Co. Ltd. worked hard to resolve the problem, experimenting with a Grade 1 chrome vanadium En50 steel sourced from contacts at Rolls-Royce.

Shell Mex and BP had produced new blends of fuel for Arthur Pratt to test, all were blends with a base of from 33 1/3% to 65% methanol, with differing proportions of benzol, acetone and aviation fuel. Pratt was searching for the fuel that gave the most power, with the minimum of heat and the lowest fuel consumption. Engine heat was proving a problem and the valve heads were a critical issue, trouble being experienced with the welded in discs in the exhaust valve heads coming out and the supplier, Motor Components, worked hard to resolve the issue.

By the time of the Spanish GP in late October, the engine was giving good results and power and Vandervell hoped for a good showing, but Collins crashed in practice and the car could not be repaired for the race, so the team withdrew and returned to Acton; there was much to do in preparation for the 1955 season.

David Yorke, who had shown his potential for organisation in managing Peter Whitehead when he drove for Vandervell, had now been taken on as team manager of the Vanwall racing team. At Acton, Frank Davis had been moved from the main factory and placed in charge of the racing shop (under Fred Fox) and the racing staff had been increased considerably with the transfer of specialist machinists from the VP tool room. The intention was to run a two-car team in 1955 and Mike Hawthorn had been signed up to drive with the other place going to Ken Wharton, after attempts to sign up Peter Collins had failed.

Engine development was well in hand, with Leo Kuzmicki now working at Maidenhead in charge of engine design and Salters were working on the valve spring problems. Towards the end of the year, Vandervell and Harry Begg visited Robert Bosch and Daimler Benz in Germany to follow up progress with the fuel injection layout to be used on the Vanwalls, while Eric Richter had designed a mounting for the injection pump on the front of the engine's secondary gear case which was heightened and modified to take the final pump design. Bosch delivered the first injection pump late in 1954 and installation of it started on 30 December.

4.8 Engine Development - 1955

The main focus on the engine front was to get the fuel injection system developed and working, and by February the first of the special Bosch injection pumps had been set up on a test engine. The 1955 engines were given the drawing office type no. V254 and numbered V1 onwards and the 1955 cars were now called simply Vanwall with no more reference to 'Special' and were numbered VW1 onwards. The 1954 engines were simply typed '54'.

4.8.1 Adoption of Fuel Injection

The Vanwall had port fuel injection, unlike the contemporary Mercedes Benz W196 and 300 SLR racing cars which had direct fuel injection (some early reports wrongly stated the Vanwall had direct fuel injection).

The Bosch four-plunger 'jerk type' injection pump was mounted on the front of the engine, directly above the magneto, angled on its axis to the inlet side. It was gear driven from the drive shaft for the magneto in the secondary gear case. There was a drilled overhung bracket bolted to the face of the exhaust cam box that supported the end of the injection pump, bracing it against the vibrations of the Big Four.

Four steel pipes connected from the Bosch pump to injectors screwed into bosses on the underside of the inclined inlet ports in the cylinder head. The injectors were aligned horizontally, very close to the inlet valves and the fuel was sprayed onto and across the back of the inlet valve heads.

Fuel delivery was both timed and metered and was injected at a pressure of 450psi (Edward Eaves states 660psi in the VP brochure).The 'rich setting' delivery started 01° ATDC and continued for 120°, but actual injection was 30° later due to friction in the pipes, so at the port it began at 31° ATDC and finished at 29° BBDC.

The injection pump received fuel from the existing belt-driven Ceco fuel pump (mounted low on the side of the crankcase as before) after passing through a Purolator fuel filter.

The Amal carburettor bodies, less jets and needles, were retained to regulate air flow only. Consequently, they only had the slide throttle barrels still activated by the quadrant and cable system previously used. Surprisingly, the inlet trumpets on each Amal body had much smaller radii bell mouths than before, but that would be changed in the future. The original remote float chambers were naturally not needed now.

As supplied, the Bosch injection pump regulated the amount of fuel to be injected as a function of induction pressure and engine speed, by the combination of a venturi throttle and aneroid sensors to ensure the correct air/fuel ratio was maintained (as used on the Mercedes Benz production 300 SL). This was tried on the Vanwall engine and gave good results on the test bed, but was rejected because of poor throttle response in circuit testing. In its place, a purely mechanical system was devised by Kuzmicki and Vandervell that linked the injection pump's control rod rack (which regulated the amount of fuel delivered by each plunger) directly to the four air slide throttle's operating shaft, located on top of the inlet cam box. This was achieved by a complex arrangement of pull-rods, a rotating shaft and lever arms that extended around to the front of the injection pump and connected to the fuel control rod rack. The rotating shaft (or 'control rod') was an intermediate component that connected the linkage from the air throttle shaft to the linkage connecting to the injection pump rack and it was located alongside the injection pump. It pivoted at one end in an extension off the side of the camshaft gear drive tower and at the other end in a perforated support plate off the end of the injection pump.

The fuel injected 2.5-litre engine weighed 163kg. complete with clutch and the adoption of fuel injection had given an increase in power, although again no figure was officially released. A fair estimate would be 270bhp. The compression ratio was 12.5:1.

All through the early months of 1955 there was intense work to have two cars fitted with fuel injection ready for the new season. Considerable work was also done on the suspension and chassis to better cope with the engine's power and improve roadholding. But when Hawthorn tested the car early in April at Odiham airfield, he found there was still a large flat spot between 4,000 and 5,500rpm but plenty of power above that; more work was needed and 1955 would prove to be a difficult year.

4.8.2 Lubrication System

The engine's external oil lines were replaced with Super Metalflex stainless steel flexible pipes, with the oil feed to the camshafts via a distribution block on the right face of the gear drive tower and flexible pipes.

4.8.3 The Competition

1955 was the first full year that the Vanwall competed with its definitive 2.5-litre engine.

The opposition was formidable, the straight-8 Mercedes Benz W196 driven by Fangio and Moss developed 290bhp by year's end and dominated the season to give Fangio his third World Drivers Championship. The Italian teams provided a strong challenge to the Mercedes, particularly the V8 Lancia D50 cars of Ascari and Castellotti until the team withdrew mid-season because of financial difficulties. Ferrari fielded its 4-cylinder 625 F1 and 555 Supersqualo cars and scored a fortunate win at Monaco when the lead Mercedes and Lancia retired. The 4-cylinder P25 BRM didn't appear until later in the year and although it showed speed it lacked reliability and development. Connaught's B-type car with its Alta-based 4-cylinder engine was hindered by lack of finance and had a limited season, but showed its potential by winning the non-championship Syracuse GP against the works Maserati team at the end of the year. The French team of Gordini with its 6-cylinder Type 16 and 8-cylinder Type 32 cars also lacked finance and development and were only midfield runners.

4.8.4 Vanwall Race Performance

The revised cars with fuel-injected engines were ready by April, and Mike Hawthorn and Ken Wharton had been signed on as drivers.

The first race appearance in 1955 was at the International Trophy meeting at Silverstone on 7 May, where Hawthorn set equal fastest qualifying time to Salvadori on a Maserati 250F. Hawthorn's race lasted 15 laps before stopping with an oil leak from the gearbox (the gearbox was pressure fed oil from the engine). Wharton, who started on the third row, had to pit twice because the throttle linkage was not opening fully, but then crashed when he attempted to un-lap himself and pass Salvadori's leading Maserati .The car caught fire and Wharton was injured.

For the next race, the Monaco GP on 22 May, only Hawthorn was entered. He found the cars handling wasn't up to the standard of the frontrunners but still qualified on the fifth row of the grid, 4.5 seconds off Fangio's pole time of 1.41.1 in a Mercedes. In the race, the car only lasted 23 laps when a ball joint in the throttle linkage came adrift and the engine stopped. The car was retired.

Only Hawthorn was entered for the Belgian GP at Spa on 5 June. He qualified ninth, a telling 14.9 seconds slower than the pole Lancia D50 time of 4.18.1, and retired from the race on lap 9 with an oil leak from the gearbox.

After the problems with the throttle linkage in the first two races, Vandervell approached Rolls-Royce for advice in combating the vibration-induced problem .They suggested using Hoffman ball bearings in the end supports of the control rod and also gave advice on how to install a fail-safe washer into the linkage joints.

Kuzmicki wasn't happy with the state of the inlet and exhaust valves after the Monaco race and worked closely with Motor Components on the matter of nitriding and problems of the valve stems 'picking up'. Motor Components felt it was possible that the cylinder head was distorting at high temperatures, which could be the cause of the valve stem problems. Problems had already occurred with the cylinder head sealing rings because of this. Kuzmicki had started work on redesigning the cylinder head to incorporate bigger valves around this time and these were all matters for consideration in the design of the new head.

Another serious problem on the engine front was that bench testing and track running had revealed that the flange mounting of the Bosch fuel-injection pump was fracturing. Bosch made modifications incorporating a flexible coupling in the drive but they eventually concluded that the problem was caused by the engine's high frequency vibrations and not the pump itself. These vibrations were adversely affecting the throttle linkage too and with the overhang on the pump, it was found that vibrations built up in the linkage causing movement of as much as ½ inch (12mm). The first rods used in the linkage were quite small in diameter (the pull rods were very slender) and thicker and thicker rods were tried, but they still broke. Concurrently, VP and Bosch worked on improving the actual fuel injection process, with advice on nozzles and spray angles coming from Daimler Benz.

Hawthorn had cancelled his contract with VP after the Belgium GP and Harry Schell was taken on to partner Ken Wharton. Two cars were entered in the British GP at Aintree on 16 July where Schell qualified on the third row, 3.4 seconds off Moss' pole time of 2.00.4 in the Mercedes, and Wharton started 15th, 8 seconds off pole. In the race, Schell stalled at the start but got going and made good progress passing the Ferrari team, only to retire when he pushed the throttle pedal off its mounting. Wharton had to pit to repair a fractured oil pipe when Schell took over but still finished last.

In the aftermath of the Le Mans disaster many European GPs were cancelled, so Vandervell entered his cars in some of the smaller British events. Schell drove in the International Trophy race at Crystal Palace on 30 July, winning Heat 2 (the first win for a Vanwall) and came second in the final, the car running trouble-free.

Then Schell and Wharton competed in the Redex Trophy at Snetterton on 13 August, coming first and second in the F1 event, beating Moss on his private Maserati. In the F Libre race only Schell competed and he had to retire while leading because of a fuel tank leak.

Next was the Italian GP on the banked Monza track on 11 September and three cars were taken, one as a spare, showing the team was getting established. Schell qualified 11th, 9 seconds off the pole time of 2.46.5, while Wharton qualified a further 4 seconds slower. In the race Wharton retired on the first lap when the steel bracket supporting the fuel-injection pump fractured and the pump came away from its mounting, while Schell retired on lap 8 with a broken De Dion tube.

The team next entered the Gold Cup race at Oulton Park on 24 September with cars for Schell and Titterington (replacing Wharton who wasn't fit). There was a strong Italian entry but Schell retired on lap 17 when fourth due to a rear driveshaft failing, Titterington finished third behind a works Maserati and a Ferrari-entered Lancia D50.

The final race of the season was a small meeting at Castle Combe on 1 October, the Avon Trophy, where Schell won both events.

In November, Stirling Moss test drove VW2 and found the engine was flat below 4,700rpm and had a misfire at 6,800-7,000rpm. Two weeks later, he tested VW1 against a BRM and a Connaught and found the Vanwall fastest and much improved.

During the year it was found that in hot weather, such as encountered at Monza, the fuel-injection unit was prone to vapour-lock when the engines were switched off after running. The Vanwall mechanics would often have to swath the injection pump with rags soaked in cold water to avoid this, both in practice in the pits and on the grid when waiting to re-start the engines, at the one-minute signal.

Back at Maidenhead, Kuzmicki was pressing on with engine development and by September he had drawn up a 20-point programme for the winter months, aimed at getting more power and improving reliability for 1956. Key aspects targeted were endurance testing of new inlet and exhaust valves to cure the problem of retaining the welded in discs in the heads of the exhaust valves; testing a new combustion chamber design with the inclined valves offset from the cylinder centre-line; design of an improved secondary gear case with better mounting points for the injection pump and magneto; the use of rubber oil seals on the short 'pushrods' (tappets) of the valve gear to stop oil leakage from the cam boxes and a comparison between the port injection used and direct fuel injection. Vandervell didn't approve all 20 points targeted and most of the work was focussed on camshafts, cylinder head design, fuel injection control and exhaust systems. Kuzmicki did carry out experiments with direct injection on the now un-used 2.3-litre engine, but they decided to continue with the port fuel injection system already adopted.

4.8.5 1955 in Review

4.9 Engine Development - 1956

1956 was a pivotal year for Vanwall, over the winter of 1955-'56 Vandervell had engaged the services of Colin Chapman of Lotus fame to design a proper space-frame for his cars and to carry out modifications to the suspension to improve roadholding. He had also asked Frank Costin, who worked at the De Havilland Aircraft Company in charge of aerodynamic testing, to design a low-drag body to clothe the car. Costin produced a distinctive aerodynamic shape that set new standards for GP cars, a shape that set the Vanwall apart. It was smooth, high-tailed, with an elongated nose and low drag (cd abt. 0.6) and although it had more frontal area than the opposition at 1.16 m2 (12.5 ft2), the new-shape Vanwall only required 51.5bhp to achieve 100mph and had a top speed of 175mph with the 275bhp available.

The proven Goodyear-derived disc brakes were carried over and the gearbox was modified by Porsche to have 5 speeds with synchromesh.

The already powerful Vanwall engine was further worked on with significant detail changes to complement the new car and increase power and improve reliability. Kuzmicki now had three mechanics working with him on the test beds at Maidenhead.

4.9.1 Cylinder Head and Valve Gear Changes

Harry Weslake, the engine gas flow expert who knew Vandervell well, was now involved with engine development and worked with Leo Kuzmicki through the winter on the design of modified cylinder heads and by early 1956, Aeroplane and Motor Aluminium Castings were making the new heads. These heads still had the valves set symmetrically at an included angle of 60°, but the intersection point of their axes was offset 4.3mm (0.17”) to the exhaust side of the cylinder centre-line (rather than on the centreline as before) to provide room for a larger inlet valve.

The cylinder heads were otherwise the same as before, very shallow, measuring only 100mm from the top face to the fire joint. The camshaft gear drive was altered to align with the revised camshaft positions.

The inlet valves were 53mm in diameter with 48mm ports and the exhaust valves were 45mm in diameter with 43mm ports. Motor Components Ltd. experimented with nitrided and un-nitrided exhaust valves to try and overcome the problem of the welded disc in the hollow valve heads failing, but one of them broke after 11 hours running on the test bed, so more work was required.

4.9.2 Crankcase Changes

The bottom end of the engine had proved very reliable, but modifications were made to the crankcase to ensure it would continue to cope with the increases in power being realised. The crankcase was modified in several ways, and one was to accommodate a larger front main bearing.

The other modification was to positively secure the ten engine tie bolts to the crankcase, where they passed through it. This was achieved by incorporating ten circular steel dowels inserted horizontally into openings formed in the upper part of the crankcase faces, two at each end and three to each side, positioned in-line with the tie bolt passages. The dowels had vertical threaded holes through which the necked tie bolts were screwed (they had a threaded mid-section). Small grub screws in the dowel's centres secured the fixing. This arrangement meant the tie bolts were now secured to each of the components they passed through, making a very rigid structure, clamping the heads to the cylinder barrels, crankcase and main bearing caps.

To suit the new space frame, the crankcase no longer had the cast mounting 'feet', instead tubular steel frames were bolted to each corner of the crankcase, extending out to mountings on the chassis frame.

By March, new castings had been made by Aeroplane and Motor Aluminium Castings, incorporating these changes.

4.9.3 Engine Induction Changes

As installed in the new Costin-bodied car, the engine's air intake was much improved. The inlet trumpets on each of the Amal air throttle bodies were given much larger radii bell-mouths similar to those used in 1954. These intakes were sealed in a rectangular sheet aluminium plenum box, fed outside air by an aircraft-type NACA duct, set into the bonnet top, as part of Costin's attention to low drag. The plenum box was flush with the underside of the bonnet and had a detachable lid. Later in the year the plenum box would be fabricated in glass-fibre. Interestingly, some visiting aerodynamicists from the Royal Aircraft Establishment at Farnborough thought the use of a sunken NACA duct in the double curvature Vanwall bonnet was not effective and recommended a raised air intake (like that used previously), but based on his experience of motor racing requirements, Costin stuck with his design. (In 1984, Costin recounted how he was summoned by Vandervell to Maidenhead at 3am one morning to hear an engine running and that GAV was the only 'bloke' who could give the final magical tweak to the Bosch injection system.)

4.9.4 Exhaust System Changes

The exhaust system was similar to that used in 1955, with four primary pipes grouped together feeding into a collector, but the pipes were angled up more, so that the four grouped pipes exited in the bonnet top where they were recessed into a trough and were flush with the bodywork to reduce drag, only the tail pipe was proud of the car's body.

4.9.5 Lubrication System Changes

The oil tank was now positioned in front of the engine, sitting beneath the top transverse chassis tube that braced the car's front spring towers. The tank was formed to fit into the trapezium-shaped space across the chassis at this point. The filler for the tank was on the back left-hand side and the tank held oil for the common use of both the engine and gearbox. The oil filter was to the right of the engine. Later in the year, a small chamber was mounted on top of the tank, possibly a de-aerator. The integrated oil/water cooling arrangements are described in the next part.

4.9.6 Cooling System Changes

A ducted Marston cross-flow radiator (with the air vented out underneath the nose) was fitted ahead of the oil tank. The radiator core was in three individual but integrated horizontal sections, the top and bottom ones were each only about 14% of the total core depth, much smaller than the main middle core. The top core was for engine oil cooling and flowed from right to left. The middle larger core was for engine water cooling and flowed from left to right. The lower core was for gearbox oil cooling and flowed from left to right. Because the cores were combined there was also a degree of heat exchange through the matrix, from the hotter oil to the water as well as the primary heat exchange to the air. The top and bottom feeds both returned their cooled oil to the oil tank. There was a scuttle-mounted water header tank.

4.9.7 Engine Output

A power curve recorded by Weslake in 1956 showed the engine had a good spread of torque from 4,500rpm-7,000rpm and developed a maximum of 276bhp at 7,350rpm (equivalent to a bmep of 195.9 psi). Maximum torque was 218.2 lb ft at 5000rpm, equivalent to a peak bmep of 216.7 psi. Impressive. The mean piston speed at maximum power was 21.07m/sec (4158ft/min).

4.9.8 The Competition

Daimler Benz had withdrawn from racing at the end of 1955, so in 1956 the Vanwalls were faced with the Ferrari-modified V8 Lancia D50s (gifted to them after Lancia's withdrawal), with the team led by Fangio, and the works Maserati team with developed 250Fs and Moss on the team. The Italian teams dominated the season with Fangio gaining his fourth World Drivers title. The BRM again showed speed but lacked reliability while Connaught was limited because of lack of funding but showed potential. Again Gordini struggled in midfield.

4.9.9 Vanwall Race Performance

By mid-March, the first of the new cars was tested at Goodwood and Harry Schell and Maurice Trintignant had been signed on as drivers. A two-car entry had been made for the International Trophy race at Silverstone on 5 May 1956, and Stirling Moss took Trintignant's place, as the Maserati team weren't entered. Moss and Schell dominated practice and Moss went on to win ahead of the Ferrari team, but Schell retired with a fractured injection pipe. A promising debut for the new Vanwall, but a worry about reliability.

The next event was the Monaco GP on 13 May with Schell and Trintignant driving. The cars weren't as suited to this circuit but nevertheless Schell qualified fifth on the grid, 1.6 seconds off the pole time of 1.44.0, with Trintignant equalling his time for sixth on the grid. In the race, Trintignant retired with a cracked cylinder head when damage to the nose intake caused overheating and Schell crashed avoiding another car.

Meanwhile engine research continued and a decision was made, following discussions between Vandervell and Rudi Uhlenhaut of Daimler Benz, to try pistons manufactured by the German firm of Mahle .Up till then, Vanwall pistons were modelled on the works Norton racing pattern, forged by High Duty Alloys in RR59 and finished by Hepworth & Grandage. Now based on this experience, VP evolved a new design which incorporated the use of a special wire circlip for retaining the gudgeon pins as used in the Mercedes-Benz racing engines. This design was sent to Mahle who suggested numerous changes based on their experience and although not all of these were accepted by VP's drawing office, a final design was agreed upon and an order placed. The Mahle piston would be 16 grams heavier than a Hepworth & Grandage one but Mahle claimed it would be stronger, withstand higher temperatures and have less friction, but they would not be ready until later in the season. Mahle used their own alloy Mahle 124, which they said was equal to RR58.

The problems encountered in sealing the cylinder head fire joints, with the high compression ratio used and the considerable bmep developed, were finally solved by adopting a stainless steel and Nimonic 75 material ring joint manufactured by Coopers Mechanical Joints Ltd., consisting of a pack of narrow corrugated and flat steel rings encased within a spun and folded outer casing. This fitted around the cylinder barrel where it spigoted into the cylinder head, sitting between the top flange of the barrel and the cylinder head face and was compressed when the head was torqued down. This proved very effective, although some problems would reoccur, caused by overheating when using Avgas in 1958.

The cars were next entered in the Belgian GP at Spa on 3 June. Deficiencies in their handling showed up in the high-speed corners of the circuit but their straightline speed was impressive. Schell qualified sixth 9.2 seconds off Fangio's pole time of 4.09.8 with Trintignant seventh fastest. In the race Schell ran well and finished fourth but Trintignant retired with fuel injection mixture problems causing a misfire.

For the French GP at Reims on 1 July, Vandervell entered three cars but Trintignant couldn't drive as he was contracted to debut the Bugatti Type 251. As BRM hadn't entered, Hawthorn reached agreement to take his place and Colin Chapman was engaged to drive the third car. In practice Hawthorn and Schell showed how fast the Vanwall was with Schell qualifying on the second row 2.8 seconds off the pole time of 2.23.3 with Hawthorn next fastest, but Chapman was out as he crashed into the back of Hawthorn and the car couldn't be repaired in time. In the race Schell retired his car because of gearbox problems which caused him to over-rev the engine, so he took over Hawthorn's car, caught up to the lead Lancia-Ferraris and raced head to head with them easily matching their speed until a problem with the fuel injection control rod linkage caused him to pit for repairs. He then went on to finish tenth.

Three cars were entered for the British GP at Silverstone on 14 July for Schell, Trintignant and a one-off drive for Froilan Gonzalez. Pole went to Moss on Maserati with a time of 1.41, with Gonzalez and Schell on the second row three seconds slower. Trintignant was a further four seconds slower on the fifth row. In the race, a universal joint in one of the halfshafts snapped on Gonzalez's car at the start and both Schell and Trintignant suffered fuel starvation caused by blockages in the fuel system and had to retire (Schell was second fastest on Hanger Straight to Hawthorn's BRM). The fuel problem was caused by small deposits from the fuel tank sealant coming away and blocking the very fine filters necessary for the Bosch injection system. The sealant would not be used in the future, instead relying on the accuracy of tank assembly to avoid leaks.

No entries were made for the German GP on 5 August as the cars couldn't be prepared in time.

Vandervell entered three cars in the Italian GP at Monza on 2 September, for Schell, Trintignant and Piero Taruffi who qualified fourth, 2.8 seconds off the pole time of 2.42.6. Trintignant and Schell were on the fourth row and although Schell held second place in the race for quite some time, all three cars retired, Schell and Taruffi with leaking gearboxes and Trintignant with a broken front coil spring mount. Mahle pistons were used for the first time. (The underfunded Connaughts took impressive third and fifth places.)

By September, Leo Kuzmicki had left the Vanwall team and moved to Humber Ltd. as a senior development engineer, while Eric Richter had also left. So there was now no resident engine development engineer at VP.

Harry Weslake became more involved now and discussed with Vandervell the potential for more power for the coming season by using oxygen-bearing fuels such as nitro-methane mixed with ethyl alcohol instead of methanol. Shell Mex and BP blended new fuels for experiments on the engine test beds, using an ethanol/nitro-methane mix as suggested by Weslake. The fuel was called BPV/E, with 36% ethanol, 27% benzol, 27% aviation petrol and 10% nitro-methane. There was another fuel, BPV/D, which used methanol in place of ethanol. Vandervell sought further help in this field of expertise and contacted Joe Craig, who had retired from Norton and had a lot of experience in using these type of fuels in the works engines. Kuzmicki was still in touch in a consultant role, even though he was now with Humber. So in effect, there were three experienced engine designers that Vandervell could call upon.

Engine development now focused on better reliability, especially in the valve gear. The hairpin valve springs had suffered numerous breakages, notwithstanding the efforts of suppliers, George Salter & Co Ltd. and Herbert Terry & Sons Ltd., and Rolls-Royce's help with materials (requested by one of its engineers who had joined VP). So Fred Fox contacted the German firm of S. Scherdel KG and sent them Rolls-Royce's recommended specification for the springs to be wound from chrome vanadium wire to DTD 4A or En.50 material (this wire was centreless-ground and polished and supplied in straight lengths) and the German firm took up the task with enthusiasm.

At the end of October, it was announced that Stirling Moss had signed with Vanwall for 1957 and by November Tony Brooks had signed up alongside Moss. Vandervell budgeted for five cars and seven engines for the next season.

Throughout December, new engine parts were under test at Maidenhead and 285bhp at 7,300rpm was now the normal output and work continued to ensure this power could be maintained for long periods. This figure represented a peak power bmep of 203.6 psi. There was nothing wrong with the engine's design. The cooling effect of alcohol fuel was necessary to produce this level of power, but the Vanwall (and Ferrari) fuel blends had a much lower proportion of alcohol than that needed by rivals Maserati, Connaught and BRM.

During this testing, one of the new Mahle pistons broke and it was sent back to the manufacturer for examination. Mahle traced the failure to the notch in the gudgeon pin hole which was used for dismantling the gudgeon pin circlips and they proposed to delete this notch from future pistons. Fred Fox wasn't overly convinced that the pistons were made from the best possible material, notwithstanding Mahle's assurances that their alloy was equal to RR58. Hepworth & Grandage made their pistons from RR59 alloy whose main attribute over Mahle124 was that it was stronger, 24 tons/sq.inch compared to 18.3 tons/sq.inch. So both firms went ahead with their contracts and duplicate stocks were built up, while test bed work evaluated both types.

4.9.10 1956 in Review

4.10 Engine Development - 1957

The four main areas for engine development in 1957 were to address the problems of valve and valve spring breakage, and the long running problems of fuel injection pipe fracture and throttle linkage breakage. Bosch and Daimler Benz had both suggested that these last two issues were caused by the big four-cylinder engine's high-frequency vibrations w hich were particularly bad at 4,500rpm and 7,000rpm.

The German hairpin valve springs made by S. Scherdel KG were not proving any better than the British-made ones. The decision to follow Norton and Ferrari/Thin Wall practice of using hairpin valve springs was proving to not be the best idea. To try and alleviate the problem before any springs were used in an engine they were run on a test-rig using an inlet camshaft as activator for one hour at 2,000rpm, then ten minutes at 7,000rpm and finally 50 minutes at 4,000rpm. This cycle was repeated over 15 hours and then the springs were fitted to an engine which was then run on a test-bed. Failures still occurred both on the test-rig and on the test-beds, but some improvement was made. Pat Black who had joined the Acton engineering department from the De Havilland Aircraft Company (having previously been with ERA) was heavily involved in this testing.

Although the number of engines hadn't increased (there were nine in total: the 2-litre, the 2.3-litre and seven 2.5s) engine components such as cylinder heads were built in larger numbers to replace damaged ones and for experimental use. At this stage, engine numbers ran to V7 (later to V9 with replacements for two destroyed in crashes) while cylinder heads were beyond number 40. Several were cut open to study port shapes and casting quality while one with Weslake had the four combustion chambers and their porting modified in four different ways for evaluation. Quite a few were scrapped after problems with overheating had cracked the castings. The high standard of workmanship available from the VP tool rooms meant that parts could be made fully interchangeable to simplify assembly and repairs.

A nice touch for 1957 was the name Vanwall now inscribed into the cover plate of the exhaust cam box of the engine.

4.10.1 Lubrication System

A cylindrical de-aerating chamber was mounted vertically on the top of the oil tank (in front of the chassis cross tube) to separate air from the oil before it was drawn from the tank by the engine pressure pump.

This was replaced for the last race entered in 1957, the Moroccan GP, by a long cylindrical de-aerating tank mounted horizontally above the oil tank and attached to the top bodywork support frame. This supplementary tank was connected to the top of the oil tank and had the engine's hot water offtake plumbed through it before that pipe connected to the radiator .This does not appear to have a functional purpose, rather it seems to be that space limitations caused by the de-aerating tank's position meant that there was no other route for the water pipe. This new tank allowed more oil to be carried, helping to alleviate the load on the lubrication system that served both the engine and gearbox. The integrated oil/water cooling arrangements were as before.

4.10.2 Cooling System

The same three-segment radiator for water and oil cooling was used with a scuttle-mounted water header tank, but a thermostat with by-pass was now fitted into the engine's hot water offtake pipe, upstream of the radiator.

4.10.3 Engine Output

A VP power curve of race-winning engine V4 tested before the 1957 British GP at Aintree showed:

The apparent lack of increase in power over that recorded by Weslake in 1956 could be down to differences in the dynamometers and testing procedure at Weslake and VP, or, as the power was the same as that for engine's set-up for the 1957 Monaco GP where peak power was sacrificed for more mid-range punch, it could be that this engine had a similar set-up (see part 4.10.5). The mean piston speed at this maximum power was 21.21m/sec.

Autocar magazine of 28 March 1958 quoted a reliable source as stating that peak power achieved during 1957 on free fuel using approximately 60% methanol was 290bhp at 7,400rpm on a compression ratio of 12.5:1.

4.10.4 The Competition

In 1957 the steadily improving Vanwalls took the challenge to the opposition. Maserati fielded a modified development of the 6 cyl. 250F which would give team leader Fangio his 5th World Drivers’ Championship, they also produced a 60o V12 engined T2 version of the 250F that was tested during the year and raced once ,it produced 310 bhp and was possibly the only engine to develop more power than the Vanwall 4 cylinder engine that year. Ferrari fielded a final modification of the V8 Lancia-Ferrari, the tipo 801, which was slimmer without the previous faired-in pontoons along the sides and Hawthorn and Collins were part of a large team of drivers. At the end of the season Ferrari raced a new 2.4 litre V6 246 F1 car on AvGas , in preparation for the 1958 regulations. BRM started to produce better results and in a portent of changes to come, Cooper produced a rear-engined car powered by a 1.96 litre 4 cylinder Coventry Climax FPF engine, which performed well on the tighter circuits. Connaught had developed its B-type and a new C-type (not to be raced) but by mid-year the works team was withdrawn and closed down because of a lack of funding and the same happened to the Gordini team, earlier in the season.

4.10.5 Vanwall Race Performance

The first race entered in 1957 was the Syracuse GP in Sicily on 7 April where Moss qualified third 0.8 seconds off pole time, with Brooks next, 0.5 seconds slower. Moss and Brooks were running first and second early in the race when the injection pipe to the no.1 cylinder broke on Moss's engine and he had to pit to have it replaced. He fought on to finish third behind the Ferraris. Brooks retired when the water offtake pipe split, causing misfiring and overheating, which cracked the cylinder head. Brooks found the Lancia-Ferrari had an edge in acceleration.

It was clear something had to be done to cure the persistent problems of broken injection pipes and throttle linkages and Fred Fox had made contact with Palmer Aero Products Ltd. in London regarding the use of their Palmer Silvoflex high-pressure flexible rubber fuel lines, which were guaranteed to withstand the 450psi delivered by the Bosch pump to the injectors. Vandervell realised that part of the problem was the overhung mounting of the injection pump on the front of the engine, and with the benefit of hindsight it should have been mounted elsewhere (this would occur in 1960, when the engine was adapted for a rear engine mounting). Also Rose Brothers (Gainsborough) Ltd. had produced spherical universal joints to fit in the throttle linkages, in an attempt to address the problem.

While Palmer were working on developing the new fuel pipes, two cars were entered in the Glover Trophy at Goodwood on 22 April. In practice Moss pulled 7,700rpm (under load 7,900 to 8,000rpm was the absolute limit according to head mechanic Norman Burkinshaw). The Vanwalls led the race until both retired when the control rod between the throttle linkage and the injection pump control rack broke. This was attributed to the same high-frequency vibrations that caused the fuel injection pipes to fail, and Vandervell felt that this should have been revealed in bench testing or in practice, but frustratingly, it only happened when the cars were competing.

Soon after the Goodwood race, an engine fitted with custom-made Palmer flexible injection pipes had completed five hours on the test-beds without problems. Palmer's engineers had also suggested that their Silvoflex pipe was sufficiently strong in torsion to be used as a flexible joint in the control rod to the injection pump that had broken at Goodwood. A section was fitted in the middle of the control rod and found to work perfectly, so the team was now confident that these problems were at last solved.

The apparent high oil consumption in the Syracuse GP, caused by leakage from the short pushrods in the camboxes, had been cured after Fox had sought the help of Francis Beart, the famous Norton motorcycle tuner.

While this was happening, Moss had made suggestions for changes for the upcoming Monaco GP. One aspect was to improve the engine's mid-range power to better suit the low-speed nature of the track. This was achieved by a change of camshafts and different valve timing, so that the engines gained better torque lower down in the rev range and a wider power band for the loss of 10bhp at peak rpm of 7,300rpm from the normal 285bhp. The engines in the two race cars developed 275bhp and 276bhp respectively while the spare engine gave 271bhp, the closeness of these outputs reflecting the high standards of VP engine preparation.

The Monaco GP was on 19 May where Moss qualified third on the front row 0.9 seconds off Fangio's pole time of 1.42.7, with Brooks next. Moss led the first three laps before crashing out, Brooks moved up to second place and held it to the finish. The cars had been fitted with shorter noses to reduce the risk of damage and improve cooling.

Several European races had been cancelled and during this lull the FIA had announced that from 1 January 1958, pump petrol was to be used for all GP championship races, although no definition of what constituted pump petrol had been issued. It was the oil companies that had pushed for this change, so that they could advertise that a race was won using a fuel similar to that which they sold at the pump.

Naturally, Shell Mex and BP were aware of this impending change and had been blending fuels with more and more aviation petrol of 115/145 octane (military spec AvGas) and less and less methanol, reducing it to as low as 25%, while raising the benzol content to 50%, the AvGas making up the remaining 25% .This fuel was called BPV/M while another with less benzol and more AvGas and a percentage of nitro-methane plus 0.5% of Halowax oil was coded BPV/L. Both these fuels were tested in the Vanwall engines on the brake at Maidenhead.

During this lull in racing, the team at Acton was busy preparing and developing the cars. One of the things investigated was the use of titanium to reduce weight and increase performance. In particular the possibility for the engine's connecting rods to be made from titanium. William Jessop & Sons Ltd. of Sheffield offered much useful information on their Hylite 50 specification titanium alloy material, but nothing came of the idea for its use in the engine, although it was tried experimentally for suspension and brake parts without success.

By the end of June, the new Vanwall transporter based on a Leyland Royal Tiger chassis had been completed and now complemented the existing Bedford SB transporter.

Racing resumed at the French GP at Rouen on 7 July but Moss was ill and Brooks was recovering from injuries sustained in a crash at Le Mans, so Roy Salvadori and Stuart Lewis-Evans were recruited in their places. Salvadori qualified sixth, 3.6 seconds slower than Fangio's pole time of 2.21.5, while Lewis-Evans qualified tenth. Salvadori retired from the race with broken (German-made) valve springs, while Lewis-Evans retired with a cracked cylinder head that had allowed combustion gases to over-pressurise the cooling system.

A week later was the non-championship Reims GP and Salvadori and Lewis-Evans drove again. Lewis-Evans showed his potential and qualified second to Fangio on a Maserati, 0.2 seconds slower. Salvadori was further back, 7.9 seconds slower. In the race, Lewis-Evans took the lead and easily held it for 20 laps until the sustained high speed on the long straights caused piston ring blow-by and oil mist escaped from the crankcase breathers and affected the rear brakes causing him to ease off, but he still finished third on the same lap as the leader, while Salvadori finished fifth.

After this performance, Vandervell arranged to sign up Lewis-Evans as the third driver on his team.

In preparation for the British GP at Aintree on 20 July, four cars were readied along with two spare engines. One of these engines had a new cylinder head with modified porting that improved breathing in the lower rev range, giving more power between 3,500 and 5,000rpm, while developing the same power at 7,200rpm (it isn't clear whether this engine was used in the race). All of the engines were fitted with Hepworth & Grandage Hepolite pistons, as the use of the German Mahle pistons had finally been abandoned in favour of the British-made ones in RR59 alloy.

In the race, Moss and Brooks started on the front row (Moss on pole) sandwiching Behra's Maserati, and Moss took the lead on the first lap, easily out-accelerating the Maserati down the longest straight. Moss led for over 20 laps before pitting with a misfire caused by a faulty magneto. Moss then took over Brooks' car, rejoining in ninth place, and fought back to win Vanwall's first World Championship race, after Behra's leading Maserati retired. Lewis-Evans had throttle control troubles and was disqualified for driving without a bonnet after he had stopped on the circuit to effect a repair.

Then came the German GP at the Nürburgring on 4 August and the Vanwalls were all at sea on the daunting mountain circuit. Brooks qualified fifth, 10.5 seconds off Fangio's pole time of 9.25.6, while Moss qualified seventh, 5.1 seconds further back, with Lewis-Evans ninth on the grid. In the race Moss finished fifth (pulling 7,600rpm in top down the long Tiergarten straight), with Brooks ninth, while Lewis-Evans spun and crashed after oil from his gearbox breather got on his rear tyres.

The Italians were allowed a second World Championship race, the Pescara GP held on 18 August on a long road course on the Adriatic coast. Moss qualified second, 10.1 seconds slower than Fangio's pole of 9.44.6. Brooks was on the third row. Moss took the lead on the second lap and went on to convincingly win the race, leading Fangio's Maserati by over three minutes. Brooks retired with a seized piston and Lewis-Evans finished fifth.

Meanwhile at Maidenhead, the team was busy doing endurance running of the engines, using nitro-methane blended fuels and fuels containing greater quantities of Avgas. Information and advice on using nitro-methane fuels was sought from Air Commodore Banks, CB, OBE of the Bristol Aeroplane Company, an old friend of Vandervell who had worked on Schneider Trophy aircraft racing engines. He confirmed Weslake's view that it was better to use ethanol rather than methanol as the main constituent of the fuel mixture due to its greater calorific value, especially considering the long 500km races being contested. The nitro-methane blend fuels were delivered to Acton in 50-gallon drums marked Vancomp and Vandervell referred to the fuel as 'Rod Banks cocktail'.

On the test beds, the Vanwall was developing 295bhp on nitro-methane blended fuel, but the safety margin on the pistons was marginal in endurance running.

For the Italian GP at Monza on 8 September, Vandervell was out to beat those 'bloody red cars' on their home ground. The Vanwalls dominated practice, their relatively quiet and smooth sound belying their speed and contrasting with the blare of noise from the eight megaphone exhausts pipes on each of the Ferraris. The Vanwalls filled the first three spots on the grid (Lewis-Evans on pole) with Fangio making a fourth in his Maserati. Moss went on to easily win the race while Brooks finished eighth after pitting with stuck throttles and Lewis-Evans retired with a leaking cylinder head core plug.

Work continued at Maidenhead on developing engines to run safely on blends of fuel with up to 10% of nitro-methane for a full race distance. They wanted more power but without adversely affecting reliability, driveability or consumption and this was achieved by Pratt and his team. To control internal temperatures, the engines were fitted with sodium-filled inlet valves, matching the existing sodium-filled exhaust valves and power was increased by 9-10bhp in the useful rev band of 6,000-7,000rpm without increasing the fuel consumption. Before the year was out, for a brief moment on the test bed, they had seen 308bhp from one engine and Vandervell would have preferred working over the winter on maintaining that level of power for a race distance in 1958 rather than adapting the engines to the mandated 'pump petrol'. (On the assumption that this power was developed at the usual level of 7,400rpm, it represented an astonishing peak power bmep of 217psi.)

A last-minute addition to the race calendar was the non-championship Moroccan GP held outside of Casablanca on 27 October, and David Yorke convinced Vandervell to enter to gain experience for when it became a Championship race in 1958. Three cars and three spare engines set up to run on the nitro-methane blend fuel were taken as an experiment. In the first practice the nitro-fuelled engines were used and Yorke telegrammed Vandervell that 'cars ran on cocktail, but am putting them back on beer', indicating that the standard engines were going to be used in second practice .At this race, the cars had been fitted with supplementary cylindrical de-aerating oil tanks mounted just in front of the engine hatch above the oil tank (see 4.10.1). The Vanwalls again dominated practice with Brooks on pole, Moss third fastest and Lewis-Evans fourth fastest. But Moss took ill and his entry was cancelled. Brooks retired on lap 12 with a faulty magneto but Lewis-Evans took second place to Behra's Maserati.

It appears that the Vanwalls never raced using the nitro-methane blend fuels and that these fuels were possibly only ever tried in practice.

4.10.6 1957 in Review