The Jap­pic Brook­lands bred

Nearly 90 years af­ter it went up in flames in France, the Jap­pic is back – in New Zealand.

Old Bike Australasia - - CONTENTS - Story Jim Scaysbrook Pho­tos Garth Thomas and Jim Scaysbrook.

In the mid ‘twen­ties, the mecca of mo­torised sport for both mo­tor­cy­cles and cars was Brook­lands, the huge con­crete cir­cuit south of London. The cir­cuit had been in ex­is­tence since 1907, but af­ter the in­ter­rup­tion of WW1, it re­ally took off there­after. Back then, the few off-the-shelf rac­ing ma­chines that were avail­able were pro­hib­i­tively ex­pen­sive to all but a se­lect few, so the most com­mon method was to build your own. One such cre­ation was the Jap­pic Cy­cle Car – a com­bi­na­tion of car and mo­tor­cy­cle com­po­nents and think­ing, which was ini­tially fit­ted with a 344cc twin-port J.A.P. en­gine, chain-driven via a three-speed gear­box to the rear wheels, which like the front wheels, had mo­tor­cy­cle ori­gins. Only the rear wheels had brakes which were hand op­er­ated by a lever. The Jap­pic was de­signed by Mr H.M. Wal­ters, who had been a very suc­cess­ful mo­tor­cy­cle racer and en­gine tuner at Brook­lands, with the chas­sis and body­work done by Jarvis of Wim­ble­don Ltd. The frame it­self was made from Ash tim­ber, held to­gether with steel flitch plates and tubu­lar cross­mem­bers, and the body con­tained two seats for driver and pas­sen­ger, al­though the lat­ter had to sit side­ways with one arm out the rear. The en­gine sat be­hind the front axle, linked by chain to the gear­box which was lo­cated un­der the driver’s knees.

The rear axle was lo­cated by long tubu­lar ra­dius rods in­cor­po­rat­ing fric­tion dampers at the front an­chor­ages, which were aligned with the gear­box main shaft to avoid vari­a­tion in chain ten­sion and spring de­flec­tion. The Jap­pic was dis­played at the 1925 London Mo­tor Show on the Jarvis stand, and over 150 en­quiries were re­ceived from prospec­tive buy­ers, but Wal­ters had no in­ter­est in pro­duc­ing fur­ther cars. First en­tered at Brook­lands on Easter Mon­day 1925, the ul­tra-light­weight Jap­pic (the driver con­trib­uted one-third of the all-up weight), set a new fly­ing mile class record of 70.33 mph – not bad for a 350, which was pro­duc­ing 42 horse­power run­ning on Cleve­land Dis­col alo­co­hol fuel. The fol­low­ing year Wal­ters re­placed the orig­i­nal en­gine with a 500. Af­ter a few more out­ings, Wal­ters sold the car to Mrs Gwenda Ste­wart, who re-fit­ted the 350 en­gine and re­named the car the Hawkes-Ste­wart (HS). In 1928 Ms Ste­wart drove the car at Month­léry, near Paris and av­er­aged nearly 71mph for 100 miles. The high-banked cir­cuit was very pop­u­lar for rac­ing and record break­ing, and the car’s co-owner Dou­glas Hawkes took one of the per­ma­nent work­shops which were lo­cated un­der the im­mense bank­ings. Un­for­tu­nately in 1932, the work­shop caught fire and the car, along with sev­eral oth­ers, was de­stroyed. Since then, a hand­ful of Jap­pic repli­cas have been cre­ated, one by ex-For­mula 1 en­gi­neer Adrian Ward in Bri­tain, and an­other by Garth Thomas in New Zealand. Garth’s fa­ther Bryan has had his mar­vel­lous work fea­tured many times in this pub­li­ca­tion, but his son is no less tal­ented. Work­ing from draw­ings and pho­to­graphs, Garth spent many hours, be­gin­ning in 2012, mak­ing his own draw­ings be­fore a sin­gle com­po­nent could be made. “Some parts had to be made twice,” Garth ex­plains with a wry grin. “I only found the ac­tual di­men­sions of the

orig­i­nally car af­ter I had started build­ing. I scaled ev­ery­thing off pho­tos, know­ing that the wheels were 21 inch and work­ing from there. The chas­sis is made in two halves from lam­i­nated Ash wood with steel flitch plates used to at­tach the sus­pen­sion and axle com­po­nents. Wher­ever pos­si­ble, I like one bolt to do more than one job. For in­stance one bolt holds the steer­ing col­umn, flitch plates and fuel tank. I thought, ‘Why use two bolts when one will do?’. “The en­gine I found on the lo­cal NZ in­ter­net trad­ing site – Trademe. 90% of the bits were present but in a sad state. It was very for­tu­nate I lo­cated it as JAP dual ex­haust port en­gines are not two-a-penny. The en­gine is a “KOC” with 500 cc 85.7mm x 85mm bore and stroke, I think about 1928. Bryan with some in­put from my­self re­fur­bished it to tip top stan­dard. So that the mag­neto drive would be true to pat­tern, lo­cated at the front of the en­gine (rather than top-rear), I man­u­fac­tured wooden pat­terns, cast and ma­chined the front mag drive; the front mag drives are very hard to come by. The Mag­neto it­self is an N1, with a mod­i­fied points cap which houses a car­bon brush run­ning on the points, wired to a kill switch lo­cated on the gear change lever, the kill switch has two func­tions, to kill the spark and stop the en­gine, the other is to “in­ter­rupt” the spark when chang­ing gear, thus sav­ing use of the clutch. “The gear­box is an Al­bion 4-speed (for­ward), from a Train jig­ger, al­though the orig­i­nal was a Sturmey

Archer 3-speed; these too are very hard to lo­cate (at a rea­son­able price). Hav­ing said that the 4-speed I be­lieve will be bet­ter per­for­mance-matched with the 500cc JAP en­gine. For the body­work, a re­quest went out to Steve Roberts in Wan­ganui – the ‘Plas­tic Fan­tas­tic’ cre­ator. He ac­cepted the chal­lenge and did a bril­liant job, as with ev­ery­thing Steve does. In true 1920’s de­sign, the steer­ing col­umn was fab­ri­cated us­ing bi­cy­cle parts, the head and lower end bear­ings were taken from a bi­cy­cle steer­ing head, us­ing a ped­dle crank as the pit­man arm, the steer­ing wheel hub was CAD de­signed and laser cut, with kahikatea wood glued to the hub and ma­chined with the use of a 1/4 round ra­dius router.” The fuel tank, which came from a J.A.P. sta­tion­ary en­gine, is pres­surised up to 3 pounds by a hand pump op­er­ated by the pas­sen­ger, and Garth has added a sad­dle on a cross mem­ber above the gear­box to stop whip and stress on the chains. The car has an un­usual rear axle de­sign; to sup­port the rear axle cen­tre from flex­ing there is a cen­trally mounted bear­ing sup­ported by a tri­an­gu­la­tion of three ten­sioned sup­port rods. Quar­ter-el­lip­ti­cal springs come from an Austin 7. It is a very tight fit for the driver – so tight that the steer­ing wheel has to be cut away to give leg room. With the cor­rect sized 2.5 inch beaded-edge tyres fit­ted, the Jap­pic mea­sures the orig­i­nal 29 inches to the ground. At one stage threat­ened with de­mo­li­tion, the Au­to­drome de Li­nas-Month­léry, where the orig­i­nal Jap­pic per­ished, is still op­er­a­tional (al­beit in trun­cated form) and holds bi-an­nual Vin­tage Re­vival meet­ings. Garth and his Jap­pic replica plan to be there soon.

Team­work! Wal­ters demon­strates the light­ness of his cre­ation at Brook­lands.

Rolling chas­sis. Twin-port JAP power, just like the orig­i­nal. Un­der con­struc­tion in Garth Thomas’ work­shop in New Zealand.

Rear axle with its cen­tre bear­ing. Tubs for driver and pas­sen­ger.

Gwenda Ste­wart in the car at Month­léry, France.

Swoop­ing ex­haust with oblig­a­tory ‘Brook­lands Cans’. Fuel tank came from a JAP sta­tion­ary en­gine. Al­bion gear­box is sup­ported from cross beam to min­imise flex­ing.

The badge of of­fice.

TOP LEFT Steer­ing wheel is cut away to clear driver’s legs. BOT­TOM LEFT Hand pump pres­surises fuel tank. LEFT Rear brake op­er­ates via link­age to rear wheels. ABOVE Aim for the bank­ing! BE­LOW Garth Thomas with his mas­ter­ful re­cre­ation.

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