ON SLOW-BARTLETT'S TRIALS SPECIAL

ONSLOW-BARTLETT’S TRIALS

SPECIAL–continued f rant page 182 How is this V-twin engine married to the chassis ? It is as ingenious as the rest of the Bartlett-Speeial. The crankease has a spigot for the attachment of a car-type clutch bell-housing but. this Onslow eschews, although the J.A.P. is transversely-mounted. Instead, he drives by a short shaft to an exposed Ford Ten flywheel and clutch assembly. TI ie flywheel has been lightened by 44 lb., the standard starter ring is retained, and it all works admirably. Between two vertical plates along the chassis backbone is mounted a layshaft carrying two sprockets. From the flywheel another short shaft, with a Ilardy-Spieer universal joint at each end, conveys the drive to

this layshaft. A •;!, in. by in. chain couples the layshaft to the •input shaft of a Ford Eight gearbox carried at the end of the chassis backbone below the layshaft. The use of two sets of sprockets enables a high or a low ratio to be used, changes of chain being possible in about 25 minutes. Incidentally, Bartlett uses dural sprockets of his own manufacture and experiences no undue wear providing adequate lubrication is provided, as it is by drip feeding oil to thern from a onepint tank. The gearbox is slightly inclined to the near side to enable the substantial rod which couples it to the forwardplaeed remote gear-lever to clear the ehain and front layshaft mounting plate. The normal top and bottom gear-ratios are, respectively, 4.5 and 16.6 to 1, using 6.00-17 rear tyres.

Further ingenuity characterises the back axle, which is of swing-axle type to give independent rear suspension. A Ford V8 differential easing is bolted direct to the back of the gearbox. From this easing the half-shaft tubes have been removed. Ford half-shafts, cut down and splined, take the drive on each side to a liardy-Spieer universal joint and from these run further eat down Ford halfshafts adapted to Ford Ten hubs. Parallel outer casings enclose these driving-shafts and Find Ten back-plates and brake drums are used. As atthe front of the CUT, these brakes have been converted to 2 LS Lockheed hydraulic actuation, and here Girding linkage also couples to an outside brake lever and sit rd ” parking ” lever. Each back-plate carries a mounting for a vertical coil spring, the upper end of which is carried by the chassis, the wheels being located by radius-arms running forward and cheekcables to control lateral movement. Ilillnum Minx phase 3 springs are used, and by screwing them into or out of their threaded top mountings their action can be varied and the gratind-eletiranee lowered or raised. Ni, shoek-absotbers are required. Minor controls are IT Bowden cables to Bowden levers for air and ignition and foot (r.h.) accelerator for the throttles. Six cables are reduced to three in a junction box on the front of the engine. The clutch is also cable-operated. A small panel on the cloissis backbone carries magneto cut-out and starter buttons, Lucas Itunp.s-switelt, and combined speedometer and rev.-counter. There is a second starter-button on the g air-lever –useful in special tests ! Believe it or not, the Ford Ten starter on the off RitiV.,

which has been rewound to take 12 volts nod rotate in the reverse direction front normal, coinnienees the lusty J.A.P. without recourse to the usual half-cornpression device. A Ford Ten dynamo on the near side of the engine is driven by whittle-belt.

A simple nose-piece and engine cover, with rigidly-mounted rear wings, all in 18-gauge aluminium alloy, comprises the body. A sheet. of gauze between engine and occupants comprises the flameproof bulkhead and Onslow lopes it passes some air—but is rather dubious. Due to its position behind the seats, the engine doesn•t get notch air and we were shown a typically-Bartlett innovation intended for summer use—-a 12-volt fan to blow air Onto the cylinders !

The front wheels are Ford Ten, drilled to save 1 lb. on each, shod with 4.50 by 17 tyres, and the rear wheels carry 6.00 by 17 Oxborrow retreads–Bartlett Will use nothing else for trials. 5.75 by 16 rear tyres were tried at first but. .a higher overall gear-ratio was deemed advisable, as well as greater grip-a -further change I o 6.00 by 18 is contemplated. This Bartlett-Special is rather heavier than its creator would wish—10i cwt.., ” wet,” by whiell I ‘mean with. three gallons of fuel and lots of Hampshire mud, the weighing being done after the -Soutlisca President’s Trophy Trial !

It. is certainly a very cleverly-conceived vehicle, and looks like being as successful as it is ingenious. But its famous builder of so many ” specials ” isn’t likely to let this be his last. Ile lots plans for a 500-e.e. rear-engined trials car, using a de-tuned ” double-knocker ” Norton engine. Amt in case air-cooling palls, he toys with the idea of a 40-b.h.p. Vauxhall Twelve engine, in the same place. Apart from his love of the trials game, Leslie OnslowBartlett is addicted to rallies, in which he has driven Fords and Sntibeani-Talbots in the past. Ile is likely to share one of the latest Inter. 195 Ferij in this year’s Alpine and Tulip Rallies.–W.B.