The Inside Story of the Sunbeam "Silver Bullet"
Interest in the Land Speed Record, an undertaking in which Britain was then supreme, was at its height during the 1930s. Consequently, when the Sunbeam Motor Company of Wolverhampton, which had built the cars that first officially exceeded 150 and 200 m.p.h. (and had also built the smallest successful LSR car, a V12 4-litre Sunbeam that did more than 152 m.p.h. and was later used for track and road-racing) announced a new onslaught with the twin-engined, 48-litre “Silver Bullet” in 1929, there was great enthusiasm and acclaim. Louis Coatalen, the famous STD Chief Engineer, had planned the monster, perhaps spurred on to break the “Golden Arrow’s” existing record of 231.446 m.p.h. because this car had been designed by a former Sunbeam engineer, Capt. J. S. Irving, after that engineer had left the declining Sunbeam Company, and it had been driven by Sir Henry Segrave, formerly Coatalen’s top driver. At all events, the “Silver Bullet” left for Daytona Beach, in America, early in 1930 amid a great deal of high-pressure publicity and much optimism, with Kaye Don, the noted Brooklands driver of Sunbeam cars, nominated as its pilot. But although the car was at Daytona for a month and made 18 runs over the official course, its timed speeds ranged from fractionally over 69 m.p.h. to a best of 186.046, over the measured mile. Thus it failed by more than 45 m.p.h. to break Segrave’s record. As Segrave had achieved the 200-m.p.h. target three years earlier after only a single practice run and the “Golden Arrow” had broken the record after making only two trial runs (and a wait of 14 days for suitable weather conditions) the previous year, the “Silver Bullet” was in deep disgrace and, as an American commentator said, “it returned to England with its bulldog tail between its legs”.
What went wrong? The inside story of the 200 m.p.h. Sunbeam having been scooped by a contemporary a few years ago, I am delighted to be able, thanks to the generous co-operation of Anthony S. Heal, the well-known Sunbeam exponent and historian, to answer in Motor Sport this question, which has posed a problem for LSR recorders for more than 45 years.—W.B.
When Louis Coatalen, Sunbeam’s Chief Engineer, decided to re-attack the LSR in 1929, he was faced with the previous findings of his racing and experimental department. The 1927 200-m.p.h. bid had been accomplished successfully (203.79 m.p.h. being officially achieved) with a monster twin-engined 44.8-litre car designed, in fact, by Irving and built economically, using outdated engines and other components, the engines being installed front and back in the chain-drive chassis. The “little” 1926 LSR Sunbeam had been a conventional racing car, with a 4-litre Rootes-supercharged V12 engine. But to go from 150 to 250 m.p.h. would require a very considerable power increase, obtainable only by using a bigger engine. That in turn would result in more drag, so Coatalen realised again that the solution was a really big car, capable of accommodating engines of sufficient size to develop the required power. He used two special V12 light-alloy, roller-bearing power units, with four vertical valves per cylinder actuated by twin gear-driven overhead camshafts over each cylinder block. It has been suggested that these were, in fact, Sunbeam aeroplane engines, or prototypes thereof, but there is evidence from official Sunbeam photographs of this LSR project that these engines were made specially for the car. They each had a capacity of 24,014 c.c., the bore and stroke being 140 x 130 mm. The cylinder banks were inclined at 50 deg., each consisting of two blocks of three cylinders, with dry liners. It is interesting that in spite of Coatalen claiming 4,000 horsepower for the combined installation, the power delivered to the road wheels was 920 b.h.p. This was estimated to be 185 b.h.p. up on the car the “Silver Bullet” had to beat, i.e., the “Golden Arrow” with its non-supercharged Napier “Lion” 12-cylinder engine, and 172 more b.h.p. than the “200 m.p.h.” Sunbeam had developed at its driving wheels, in spite of it being dubbed the “1,000 h.p.” Sunbeam.
This time Coatalen put both engines at the front of the car, coupled together. The drive then passed through a multi-plate clutch with eventual dog-clutch positive drive, to a three-, speed gearbox, with ratios of 1.125, 1.780 and 2.653 to 1. From this two splayed propeller shafts drove the back axle, via twin final drives of 12/33, the driving seat, which was slung between these shafts, being separately sprung. The chassis was sprung on very stiff i-elliptic springs and an unusual feature for a LSR car was the provision of Lockheed hydraulic four-wheel brakes, with Buxton linings. The wheelbase was 15 ft. 5 in., the car was just over 31 ft. long, and it weighed 2,500 lb., dry. Cooling was by a combination of water and ice tank, the latter holding some 5 1/2 cwt. of ice, ignition was by coil, with accumulators in the tail, charged externally, and there was dry-sump lubrication and compressed-air starting. A big centrifugal supercharger was driven from the rear engine through a train of epicyclic gears, and a friction clutch. This blower was geared to run at 17,000 r.p.m., according to hand-outs from the Sunbeam company, and it drew from two Amal carburetters. Fuel-feed was by an air-pump on the rear engine, pressurising a nose tank holding 25 gallons of petrol.
It is significant, as will he seen later, that originally the engines were to have had four Roots superchargers. Mr. Martinuzzi, who was described as Coatalen’s Secretary on the Daytona visit, came to the Sunbeam drawing-office at Wolverhampton on the “Silver Bullet” project. Remembered as an Anglophile Italian addicted to tweed suits and a Dunhill pipe, Mr. Martinuzzi was a brilliant mathematician. He worked out the complex gear-train needed to drive these four superchargers.
The scheme was dropped, apparently because the new engines gave less power than the aged, non-supercharged, “Matabele” engines used in 1927, which means less than 435 b.h.p. each, and the gear-train was thought to be absorbing their potential. Tests were run, as with the 200-m.p.h. Sunbeam, by coupling a dynamometer to each drive-shaft.
It would seem that a couple of blowers per engine would have solved the problem of feeding both engines from the single, rearmounted centrifugal supercharger, and that the blower that was substituted should have been run twice as fast, to be effective, i.e., at 37,000 r.p.m. or thereabouts.
The body, which had been wind-tunnel tested at Vickers, hugged the tops of the two engines closely. It was made in sections, of 16-s.w.g. aluminium, lettered in red, over steel hoops. The wheels were exposed, but with fairings behind them, and thre were two tail fins and an air-brake. Solid disc wheels with detachable covers carried special Dunlop 37 x 6.00 14-ply cotton tyres, slave wheels being used for low-speed runs.
This giant, but not unduly unconventional, motor car was being brought into being at the Moorfield factory at Wolverhampton in September 1929, the crankcase castings being ready by October 1st and machined the next day. Later that month the bronze gearbox casings and the engine components were being prepared. The crankshafts were turned from single billets of steel on the last day of September and machined, with segmental instead of circular webs, on October 4th. In November the engines seem to have been assembled and although it has been implied that they were sent to Daytona untested, at least one if not both was put on the test-bed at Wolverhampton, although with the water system apparently “back-to-front”, without Coatalen’s knowledge.
What were the prospects of success? Well, the “Silver Bullet” was 190 lb. lighter than the 1927 twin-engined Sunbeam, although 1,650 lb. heavier than the car it had to beat. (Incidentally, Sunbeam’s quoted the target as 231.36 m.p.h., using the lower speed for the “Golden Arrow”, later officially corrected, although it was rather late for a protest!). These, however, were dry weights; ready for action the new monster would be nearly 3/4 of a ton heavier and outweigh the “Golden Arrow” by 0.87 of a ton. Against this, its weight-per-b.h.p. was lower than that of either of those other LSR cars and its frontal area was 6.2 sq. ft. less than that of the 1927 Sunbeam. Moreover, it had been worked out that, at 200 m.p.h., air resistance would be 17 lb. sq. in. less, and even undercut that on the sleek “Golden Arrow” by 13.7 lb. sq. in. At this speed the engines would be running slower than in either of the other cars and the c.-of-g. from the front axle was 45%, against 63.5% and 56% respectively (one wonders how the data for the “Golden Arrow” was obtained!).It was confidently thought that the “Silver Bullet” would be capable of 290 m.p.h., against an “all-out” ability of the other cars respectively calculated as 210 and 250 m.p.h. So what went wrong?
The Record Attempt
The “Silver Bullet” received good coverage in the Press during the opening months of 1930. Its makers had issued a hand-out booklet describing it and listing the 38 firms who had helped specifically with its construction. These included Specialloid for the pistons, Wellworthy piston rings, Ferodo for the supercharger and main clutch linings, Hallite jointing, Avon for rubber tubing, a Dover steering wheel (separate drag arms on each side of the car from Marles steering gear were used, obviating a transverse track-rod, the base of the steering wheel being horizontal to clear Don’s legs), Hardy Spicer twin-propshafts, Rotax batteries, KLG plugs, Andre-Hartford shock-absorbers (damping springs that moved only about 1 1/2 in.), a Cox windscreen, Cornercroft “Ace” wheel discs, Smiths and Jaeger instruments, Moseley pneumatic cushions, Miller jacks, Minimax fire-extinguishers, BP fuel and Castrol oil. Curiously, the Dunlop tyres were not listed. In February the car and its packing case for the journey across the Atlantic were shown to the Press, in the presence of Louis Coatalen, Kaye Don, Mr. Kay, the draughtsman, and Mr. Rose, the Production Manager.
We come now to what this attempt was costing Sunbeam share-holders. Cyril Posthumus, in quite the best book about the LSR ever written, includes a table showing the cost of some of the cars, down the years. These range from approx. £225 for Eldridge’s 300 h.p. Fiat to £900,000 for Donald Campbell’s gasturbine “Bluebird”, the 200 m.p.h. Sunbeam being quoted at £5,400. In fact, that report previously referred to adjusts this to approx. £7,000, with another £3,000 charged to Segrave for the journey to the USA, as he refused to run in England.
The “Silver Bullet” cost a total of £15,557.60, divided up as £2,975.18 for materials, £7,794.63 for labour, £4,658.09 for on-cost, and £129.75 for outwork/special expenses. To this, the unsuccessful record bid was to add another £4,102.80. These figures are quoted in decimals but are in 1930s currency and value. Coatalen claimed that much of this was covered by sponsorship.
On February 26th all were ready to leave for the great adventure, the car in the charge of Mr. H. Wilding. He left from the Low Level Station at Wolverhampton with Messrs Garrison, Harrison, Broome, Howard, Astbury and Wood, Mr. Rose seeing them off on the 12.21 express for Southampton. At Birmingham they took on Baguley, a Dunlop mechanic. On arrival they took a tram to the Alliance Hotel, where Cunard had arranged accommodation. That evening Mr. Wilding and Mr. Harrison enjoyed themselves renewing acquaintance with friends they had made in 1914/18 when working at the Sopwith seaplane sheds.
Next day Mr. Kay arrived with Mr. Howlett and Mr. White in the works’ service car, a black Sunbeam Twenty Weymann saloon (one wonders if it has survived—Reg. No. UK 7029), which was used to convey all baggage and personnel to the “Berengaria”. The “Silver Bullet” was already on the boat, weighing 6 tons 14 cwt. 3 qr. 11 lb. in its crate. It had been brought down on a sixwheeled Dennis bus chassis, and a four-wheeler Dennis bus chassis carried the 24 cases of spares. These had left Wolverhampton on the afternoon of Feb. 24th and arrived at 13.15 hours on the 25th. Mr. Wilding was sorry to note that valuable advertising space on these lorries had gone to a competing firm— presumably Dennis of Guildford….
Sailing day was Feb. 26th and before 10.00 hours Coatalen and his party, and Don and his party, were on board. The Mayor of Southampton made a short speech, to which Kaye Don replied, but again Mr. Wilding was sorry that the name Sunbeam was never mentioned; how much better, he thought, had the car been called “Sunbeam II”. Company Directors Iliff, Gen. Huggins, Kay, and the Sales Manager, Cozens, and several racing drivers, including Eyston, Eldridge, etc., were among the party seeing the adventurers away. The “Berengaria” was under her own steam within two minutes of leaving her berth…
Travelling were Mr. Coatalen with his Secretary, Mr. Martinuzzi, Mr. Wilding, in charge of the car, T. Harrison, Foreman, A. Broome, racing mechanic, and three fitters, J. Howard, A. Astbury and F. Wood. Kaye Don was accompanied by his sister, Mrs. Rita Liversay, his Secretary, Miss Peggy Roberts, his personal Doctor, his own journalist Laurie Cade, and carburetter expert, Mr. Saunderson; in America his Manager was Mr. Sturm. This is interesting, because although Malcolm Campbell sometimes took his wife and family on LSR attempts, Segrave seems to have gone alone. As the sea crossing went on Mr. Martinuzzi and Mr. Saunderson came from their first-class quarters to meet the mechanics and buy them drinks. Later very rough weather was met. Speed had to be reduced from 25 to 14 1/2 knots, then to 12 knots; Coatalen was said to be really ill and some of the mechanics missed meal-times.
New York was made on March 4th. Kaye Don was seen to be “walking about like someone bewildered” as it was thought at first that the Customs papers for the car and spares were missing: Coatalen pulled himself together when these were said to be in the shipping manifesto but he wanted the £500 lost with the Customs on spares in 1927 to be remembered! The usual preliminaries followed, such as introductions to Mr. Sturm. the Indianapolis Speedway PRO, opening the cases of spares, each with contents’ lists tacked to the lids for the benefit of the Customs officials, and taking taxis to the New Yorker Hotel. The mechanics’ rest was disturbed there by messages that Coatalen and Don might need them to stand-by to take the “Silver Bullet” to Wanermakers’ showrooms for publicity purposes, but this was a false alarm. A “cooper” helped with the spares’ cases, the Dunlop ones being of new wood but Sunbeam’s of decayed scrap that, once opened, threatened to stay apart! There were further shocks for Wilding over the high American hotel charges (136.60 dollars for four rooms for three nights). Coatalen was installed in the Savoy Plaza and Sturm at the Pennsylvania, which were presumably even more exorbitant. Eventually the car was ofl on the train, taking some 15 hours to get to Daytona. The black attendants on the train looked for tips, Wilding notes….
At Daytona the working crew slept at the Hotel Dunham and ate at Wisteria View. The City Corporation lent a truck for taking the spares and towing the “Silver Bullet” to Shaw & Wingate’s San Juan Garage, which was situated some 1 1/2 miles from the rail head, 2 1/2. miles from the beach. On Sunday morning, March 9th, the car was taken out of its crate and steered by Don to the garage. It was found to be rusty where grease had been washed off, presumably by sea spray. The following day the tail-fins were fitted, the cushion and seating altered, and a wood block fitted by the accelerator, presumably’at Don’s request. Various small items were attended to, and the ignition accumulator was removed for charging.
The next day all wheel nuts and the ignition controls were eased and fuel tank and air-lines tested. The day after this the air-intakes, with support, and the accumulator were fitted. On March 13th the engines were started, after some trouble, as the compressed-air distributors were leaking. Don operated the throttles. The oil-release valve on the front engine was leaking, necessitating removal of undershields to fit a new rubber hose. Finally, the engines were run at 1,250 r.p.m. and appeared satisfactory.
On March 14th the great day had arrived. The silver monster was towed via South Bridge to the beach. Since it had become customary to travel to Florida for LSR attempts there was no prior testing at speed.
Now Don was ready to see what would happen Official photographs were taken in the morning and Don’s sister christened the car, but Don showed signs of becoming nervous and irritable. No timing gear was available, the Indianapolis machine not having arrived and the Daytona gear being u/s and without traps, although all the AAA top-brass was present, including Odis Porter, the official timekeeper. The “Silver Bullet” was towed off the beach at 14.30 without having being run.
Next day, the Saturday. the engines were run-up in the garage for three minutes, On K.L.G 417 long-reach plugs, and a petrol mixture containing 1/40 mineral oil for the supercharger. The Judy gear had arrived but Mr. Myers, Director of Timing and Scoring, would not be there until the Monday Kaye Don said he would do a practice run at 13.30, arrived 40 minutes late, and was clocked by stop-watches to do 144 m.p.h., estimated to be a genuine 133.33 m.p.h. over the mile. Half-an-hour later the car returned, running north, but it wasn’t timed and the engines back-fired. It was thought that Don might have been doing 150 to 160 m.p.h. past the Tower, the car steering well over the rough beach, but bumping badly. The first snag now arose. Don told Wilding he had seen 1,900 r.p.m. at 3/8 throttle. This was regarded as excellent, so no change of gear-ratio was contemplated. Hindsight suggests that Don over-estimated the speed, with unfortunate results (2,400 r.p.m. were said to equal 248 m.p.h.).
On the Sunday Coatalen arrived and endeavoured to cure some in-built maladies. To improve streamlining the exhaust pipes of the “Silver Bullet” had been recessed within the sides of the body. The heat from these had melted the rubber hoses on the side water. pipes, a temporary cure being attempted with extra clips and insulating-tape. Coatalen insisted on short exhaust outlets being taken through a cowling immediately behind the front engine. While this was being done the ice-tank was raised to give more clearance to the ignition controls, the air-brake was fitted, and the rear shock-absorbers were tightened six turns, the front ones 2 1/2 turns, in spite of the bumpy ride! It was hoped that a run could have been made to test these modifications, and the National Guard was Called out to police the course. However, the weather worsened and practice was called off.
So we come to Match 17th, with the timing gear laid out. There were nine miles over which the “Silver Bullet” could accelerate, make its bid for the World’s f.s. kilo., mile and 5-mile records, and pull up for the required reverse-direction runs. Don was to make a trial run south and then go for the records from that end of the beach, as Segrave had done in 1927 and 1929. At 16.22 all was ready, although visibility was very poor indeed. At first Don appeared to be doing about 150 m.p.h. but the car slowed, to stop at the Tower (station-5), the times giving 85.476 m.p,h, for the kilo., 69.111 m.p.h. for the mile. After hasty repairs the car was push-started, and finished the course. It began the return run but stopped twice and was towed away at 17.20. The trouble was that the very long induction pipes that fed the engines from the rear-mounted supercharger were heating-up the mixture until it ignited before reaching the inlet valves, the resultant back-firing damaging the supercharger casing.
This was a virtually incurable defect. It seems surprising that Coatalen had specified a single blower, necessitating these long inlet tracts. The Lockhart Stutz used similar blowers but it was of only 3-litre capacity. One wonders whether the “Silver Bullet” might not have taken the record unblown for although it was estimated that 333 h.p. were required to combat wind-drag alone, at 250 m.p.h. the power absorbed by the very high-speed blower and the poor volumetric efficiency implied by the exceedingly hot inlet pipes must have reduced the output very considerably. The previous seven records had fallen to non-supercharged engines and Campbell did not need to install a super-charged Napier “Lion” in “Bluebird” until he was seeking to exceed 240 m.p.h.
From this point onwards the “Bullet” was doomed. But Sunbeam’s were committed and had to do what they could. The mechanics worked most of the night, presumably patching up the s/c casing, and Don was ready at 14.55 the next day. The weather was excellent but the beach bad. Don said he would feel things out but did 168.1 over the mile and a minutes later returned, going slightly faster. The two-way kilo speed was 171.019 m.p.h. Don tried again but stopped out of sight, causing some anxiety. A float-chamber connection had broken away from the n/s carburetter, so the car was towed away. A new Amal was fitted, the battery recharged, and new carburetter securing straps fitted. These were repairs. But a bid for more speed was also made, by welding scoops to the air intakes, with balance pipes from these to the float-chambers. The blower was thought to boost at around 7 lb. sq. in., and this seems to have been a futile attempt to gain more boost.
Heavy rain hampered things next day so, Don gave his timing session to a Cummins Diesel but this, too, abstained. Opportunity was taken of the lull to lubricate the “Silver Bullet’s’ prop.-shafts with Spicer’s special grease, which involved lowering the rear air shields and drilling holes through armoured plate to reach the oiling apertures( !) Vents were also cut above the blower to release fumes, with other vents directed to force them out and the driver was given a cooling airvent. The battery was recharged. By now things were becoming rather desperate, for it was six days since the big Sunbeam, proudly displaying the American and British flags on its nose and wearing Union flags on its fins had made its first runs.
On March 20th, weather good, but the beach very bad. Don was off at 16.35. But the bumps were so severe that less than 91 m.p.h. was clocked for the mile. The car stopped on its return run. After carburetter adjustments the kilo. was done at 105.316 m.p.h.. Don bouncing around in the cockpit. Rather more than 109 m.p.h. was achieved on the return run but carburation was still amiss.
Something drastic was clearly called for. As bad conditions made further runs impossible the following day, Wilding took off with Mr. Harrison for Coatalen’s hotel, to suggest changing axle and supercharger ratios. He was told that Mr. Martinuzzi had informed Coatalen that no improvement would be gained. It could be that Martinuzzi was simply acting as interpreter for Coatalen was known to be very busy at this time and probably out of touch with the L.S.R. car. (Previously, when seeking information about it, The Autocar had reported that “When his vila and open-air drawing-office on the Island of Capri had been invaded he had just left for Paris; when enquiries were made in Paris he was out testing some of his devices. He was almost run to earth at his London office, but had just left for Wolverhampton; at the works he was invisible—particularly to journalists!”…
Rain fell on March 22nd. so, expecting an improvement on the morrow, the undershielding on the car was removed so as to inspect the shock-absorbers and brake shoes. the ignition was advanced 5 deg. to suit a new grade of plug, petrol pressure was set at 2 lb. to obviate Don having to use the hand-pump, no doubt difficult owing to the rough ride, and improvements were made to the ice-tank. Mr. Coatalen seems to have lived up to my suggestion that he was out of touch, because he told Wilding to run the engines to 2,400 r.p.m.. with 1st gear engaged, decelerate to 1,500 r.p.m., and then pull the gear-lever into neutral. This proved impossible. But Coatalen insisted on three attempts, until the first-speed shaft was strained. As Don never used 1st gear, the operation was quite pointless!
The weather remaining bad the next eight days saw more fooling about in the garage. Cleaning the car, and its clutch and lubricating the s/c bearings was routine. Extending the front exhaust pipes by 9 1/2 in., to blow out lower down the body sides, and drilling small holes in the clutch housing to allow oil to be flung out (slip was being experienced), were permissible mods, to a car untried before it came to Daytona. Coatalen’s instructions that a pusher-bar was to be made up, for starting the “Bullet” by pushing on the rear of its wind-brake, was sensible. But then he told Wilding to paint the silver car red! Later he changed this to painting the nose to the second body panel, and tins to that panel, red. A painter was found and they worked all night. The temperamental Louis loved the resultant cobalt contrasts. Alas, the local and AAA officials then said unless the car was silver, no further runs would be timed—presumably the car was registered with them as silver and silver it had to remain. The painter had to go 100 miles to Jacksonville to find suitable paint and another night was spent reverting to silver. It is difficult to conjecture what was in Coatalen’s mind. Did he think red lucky, as Segrave’s big Sunbeam had been all red? Or was this a sop to Kaye Don, whose racing cars were usually that colour? (One wonders what Robert Kersley & Co. Ltd.. who supplied the original body paint, presumably free, and may even have subsidised the venture, thought of this Coatalen, foible!) More usefully, the shock-absorbers were tightened, at Don’s request (Coatalen had one checked for tension) and wheel-changing was practised, four extra mechanics having been engaged. The best pair took 3 min. 40 sec., the slowest 4 min. 10 sec. (The LSR regs. called for a turn-round within a given time, hence these precautions.) Coatalen was now taking an interest, to the extent of saying the water-circulating pipes were completely ill discordance with the engine design. All compressions were tested, and found correct.
The weather relented after a wait of 11 days ( Segrave had to wait 14) and a serious bid was organised. The seat and cushions had been altered in an attempt to give Don a better time, a strap securing the seat cushion. Two lorries carried spares to the turn-round points, two cars were crammed with a dozen mechanics, the jacks, planks, 10 gallons of fuel, 20 gallons of water and 3/4 cwt. of ice were prepared, and the car was on the beach with 1 1/2 hours to go before low tide. A drill had been worked out. Don was to go to Station-9 on slave plugs and stop on full-throttle to burn off oil.
The “Bullet” would be turned by hand, or pulled round by the tyre lorry. Wilding, Harrison, Bowen and Bradshaw would then put in the racing plugs, tyres be changed for the special ones, and ice put in. 20 men then would push Don off, all mechanics except one returning to the zero point, where the push-truck waited. After making its first timed run the car would be man-handled round downhill, pulled away from the beach uphill by the posh-truck, which would later push-start it, staying always in low gear, after the plugs had again been changed and eight men had changed the wheels, two men per wheel.
The beach was wavy, and Don was advised not to try. But he made a test run at 178.66 m.p.h. (mile) and the proper wheels, more ice, and the KLG 464 plugs were put in, for a real bid. The kilo was covered at 182.16 m.p.h. On the return (southwards) run tin speed improved to 186.046 m.p.h. (mile). It was thought the car was doing 188 beyond the measured section. Don made another run but reported carburation problems and sent for the Amal man. However, tyres and six oily plugs were changed, ice added, and he was off again. But back-firing continued, reducing the mile speed to approx. 97 1/2, the kilo. to approx. 105 m.p.h. The tide was now coming in, so the car was ordered off and was towed away on its slave wheels. It had done 54 miles, that day.
A post-mortem showed s/c trouble at 1,700 r.p.m.; its front cover had distorted and the high-speed bearings collapsed. Fortunately, the original cover had been re-welded and machined, locally. The original 30 deg. airintakes were re-fitted. Working all night the new supercharger was fitted, with a drive ratio of 2.62 to 1 against the former 2.14 to 1. Next day Don was out on a had beach, to test the mods. At 70 m.p.h. the carburetters flooded, but after they had been drained the car got away better than ever before. But premature opening-up caused popping, so Don cut the switches, afraid of more s/c damage. The front cover had, indeed, distorted; the repaired cover was fitted, strengthened by three steel strips.
That was April Fool’s Day. At last, on April 2nd, the axle-ratio was changed, to 2.92 to 1. instead of 2.75 to 1. The external air-intakes were deleted and the holes used with the scoop-type intakes blanked off. Three large louvres were then cut in each side of the top cowling, to enable the carburetters to work in still air, with short intakes. Porosity in No. 4 plug hole was cured with an adaptor. It seems that Mr. Martinuzzi had insisted on scoop intakes being fitted at Daytona, contrary to test-bed findings!—see previous comment. But now the “Bullet” should have been truly ready, axle and s/c ratios corrected, new air-intakes fitted, and lagging round its exhaust manifolds to counteract the damaging flames from the s/c blow-off valves.
It was now April 10th, and Kaye Don’s luck did not improve. His windscreen became so badly misted up that close objects were a blur, the slave plugs got very hot and some of the 464s oiled up, and the engines again popped back. The induction tracts were full of fuel which the blower release-valves couldn’t cope with and the s/c cover had distorted 5 1/2 mm., in spite of the steel supports. The old cover was re-fitted. Surprisingly, the “Bullet” then ran as well as it had ever gone, reaching 175.72 m.p.h. (kilo.), speed increasing towards the mile, on a nasty surface. Next day the beach had improved considerably but Warren Baker said it would not allow for more than 150 m.p.h.
Then it all fizzled out. Reports of abandonment were imminent but Wilding travelled to New York to obtain confirmation from Coatalen. Don was on the train and the AAA officials were pulling out. A postponement until early 1931 was forecast. On April 13th, an unfortunate date, Wilding and Don went to the Savoy Plaza to see Coatalen. Don thought it advisable to go in alone but later Wilder, the Cummins’ man, insisted on Wilding being present. He went into one room in the Suite and found a very tired-looking Martinuzzi busily talking. Then Coatalen came in and Wilding was instructed to have the “Silver Bullet” packed up and shipped to England immediately. It was 47 days after it had left Southampton. . . .
Thus it all wound up, the car returning on the “Berangaria”, with three of the men. Prior to this Coatalen and Don had Sailed on the “Acquitania”, travelling first-class, with Wilding, Broome, Wood, Bagulay and “Dunlop Mac” in second-class quarters. The car got to Southampton on April 28th.
Postscript —The Press, having been generous with descriptions and what news there was of the project, naturally wanted to know what had gone wrong, and Mr. Wilding thought it best to hurry back to Wolverhampton, out of the way! He had compiled a full technical report which, thanks to Mr. A. S. Heal, I have been able to consult. There were stories of acrimonious sessions between Don and Coatalen and Don was accused of cowardice by some American reporters. It seems, however, that he did what he could, under very difficult circumstances. While the car steered and handled well, Don was badly bruised by the hard ride and the steering column pressed on his legs. Although as an historian I cannot overlook a report on the 18th run by Wilding that reads: “Don had stated that he would go as fast as the beach would permit, and there is no doubt that he did otherwise”, I think this can be disposed of as an unfortunate choice of words and that Mr. Wilding meant the exact opposite of what is implied. For Don did nearly 176 m.p.h., on that occasion, with the surface only good for 100 m.p.h., his goggles and screen misting-up, the engines popping and boiling….
Don might have been criticised by the uninitiated for cutting-out whenever the engines popped back. Apart, however, from the very unpleasant aspect of sitting at over 150 m.p.h. immediately behind a high-speed blower that was likely to split its casing at any moment and carburetters that were likely to catch fire, Don, as he said, realised that if the supercharger burst the car would be useless.
The post-record-bid findings were that the blower was too experimental to be any use, giving nil efficiency, escaping oil affecting the sparking plugs, and that its castings were too weak.
It should have run at 34,000 r.p.m. or so, to be effective. Coatalen’s criticism of the submerged exhaust manifolds was upheld, and there was severe criticism of the positioning of the ice-tank, “designed by someone not connected with the racing department”, as it obstructed the ignition distributors and water cocks. The s/c induction and branch pipes were of a size and length that caused a great build-up of fuel in them. causing the engines to cut out every time the driver changed up.
Oil from the blower epicyclic gears heavily fouled the racing KLG 464 plugs. This was at first attributed to engine oil pressure being too high, at 25 lb. sq. in., but a reduction to 12 lb. sq. in. failed to effect a cure. There was confusion over the air-intakes. With the two scoop-types, supplied by the Detail Department just before the .car’sailed, best results in Don’s view were obtained after 75% projecting area had been removed. Harrison then found sand in the intakes so Coatalen had them made flush with the cowling sides. This was useless, so Coatalen had the scoops re-fitted, with balance-pipes. This was difficult to do with the experimental Arnal carburetters and caused black smoke to belch from the exhausts. Coatalen was clearly not at Daytona all the time, as then “he wired instructions” to use under-cowl intakes, as arranged on the test-bed, until Martinuzzi intervened.
Surprisingly, the bad bumping was attributed to the “Bullet’s” long wheelbase, and was confirmed by Wilding when he drove a short-wheelbase Buick over the course, which was very nice compared to a longer-base Lincoln he tried. The shock-absorbers didn’t effect a cure. Spring movement was said to be a mere i-of-an-inch. The brakes gave no trouble but Lockheed’s said leverages Were too high and Don said they were very heavy. The clutch was “solid” until Coatalen had those holes drilled and it slipped over 20% of the course, until the dogs engaged. (This pleases me because as a boy I suggested a dog-clutch on LSR cars, in a letter to The Autocar.) The gearbox 1st speed gear seized on the mainshaft as reported, and it would have taken four days to rectify this.
Magnetos and twin-plugs-per-cylinder would have helped the mechanics; it is odd that the fuel lines were casually fitted, with no flexibility and not a single tap! There was no means of checking oil-level in the gearbox and the wheel discs flew off at speed….
Altogether a sorry story, for this was Sunbeam’s last competition exploit. It is sad that a few years later the old Sunbeam Co. had been taken over by the Rootes Group and Coatalen was a mental wreck. Freddie Dixon (with visions of multiple carburetters?) and Jack Field tried to tame the “Silver Bullet”, but without success. There is a fine picture in Posthumus’ book of Field fighting a fire around the cockpit, which sums up the whole matter… (The car might have taken the British speed record, while this was held by Thomas at 171 m.p.h., for if the Welshman could cope at Pendine with his crude brakes, the 4WB “Bullet” should presumably have been Safe at a slightly higher pace. But in 1929 Campbell had done 217 1/2 m.p.h. at Verneuk Pan, S. Africa, a British record, so only local honours were within reach.)—W.B.
The RAC has qualified their roll-over bar regulations which prompted readers to protest vociferously in last month’s issue. Pre-or post- 1/1/65 standard production cars, whether open or closed, will be exempt from the 1976 change of rules making roll-over bars mandatory in sprints and hill-climbs. The RAC’s Speed Events Committee says that it was never their intention to force such cars to fit roll bars.