The Four­nales

Trial Magazine - - NEWS - WORDS: JOHN HULME • PIC­TURE: TOON VAN DE VLIET

The small world of tri­als has wit­nessed over the years some engi­neers whose ideas and dreams had them think­ing out loud and well out­side the box, not con­form­ing with the nor­mal lines of what a tri­als mo­tor­cy­cle should look like. In my early teen years I rode the very for­ward-think­ing Ossa pow­ered MAC – Mac­don­ald Auto Cy­cle – built and rid­den by its builder Dun­can Mac­don­ald. It was years ahead of its time and very much the fore­run­ner of many pro­duc­tion ma­chines we would see over the years; the early Beta Zero springs to mind. Dun­can came from the fam­ily that gave us Vac­uum Form­ers (VF plas­tic mud­guards to the older read­ers) pro­duced along with his late fa­ther John and Brother An­drew. The air­craft in­dus­try has al­ways fea­tured in mo­tor­cy­cle de­vel­op­ment, for ex­am­ple with disc brakes, and it was from this area, land­ing gear on the Con­corde project, that French en­gi­neer Jean-Pierre Four­nales used his ideas and ex­pe­ri­ence to build the Four­nales tri­als ma­chine.

The project came to life over the win­ter months of 1981/1982 as Jean-Pierre had de­vel­oped his own air shock ab­sorber and de­cided to in­cor­po­rate this and his other ideas around a rev­o­lu­tion­ary tri­als mo­tor­cy­cle man­u­fac­tured as a test bed for his many thoughts.

AIR­CRAFT EX­PE­RI­ENCE

The start­ing point would be the en­gine and he chose the Ital­ian Hiro unit de­vel­oped by Sammy Miller. This was maybe not the best choice; he would have pre­ferred to use a Ro­tax en­gine but he was able to pur­chase com­plete Hiro en­gines in sin­gle units at a time. The sit­u­a­tion of the gearbox sprocket ful­crum point was eas­ily ac­ces­si­ble for him to lo­cate the swing­ing-arm pivot to re­move all is­sues of drive chain and sus­pen­sion in­ter­fer­ence when ap­ply­ing power. The ma­chine was built in a small lab­o­ra­tory, where he had ac­cess to many test fa­cil­i­ties he could use to equate the frac­ture points and un­der­stand the stresses in­duced in the frame’s fab­ri­ca­tion.

Mix­ing novel, unique ideas whilst in­cor­po­rat­ing orig­i­nal ones the main frame struc­ture was a cross be­tween a back­bone with brac­ing and an­chor points in­cluded, giv­ing a very ‘space-like’ ap­pear­ance. The steer­ing head as­sem­bly was not as we know it, with a con­ven­tional steer­ing head spin­dle. It fea­tured a clamp as­sem­bly ma­chined by Jean-Pierre from solid bil­let alu­minium, with bot­tom struts lo­cated on the other frame mem­bers to make the head an­gle eas­ily ad­justable.

SIN­GLE SIDED

A heav­ily braced, tubu­lar, sin­gle-sided swing­ing arm was lo­cated di­rectly to the gearbox out­put shaft. The rear air shock ab­sorber was con­nected di­rectly to the swing­ing arm to pro­vide a more pos­i­tive source of feed­back. Rid­den by Pierre Cauquil the ma­chine at­tracted much in­ter­est wher­ever it ap­peared. He com­peted on it in the French cham­pi­onship events as well as a few world rounds.

De­vel­op­ment fo­cused around the rear sus­pen­sion and its big­gest claim to fame was when Pierre cleared the mas­sive step at Bil­stein in the 1983 World Cham­pi­onship round. Rear shock ab­sorber de­vel­op­ment con­tin­ued, and the Four­nales Com­pany can now boast over 37 years of man­u­fac­tur­ing shock ab­sorbers in fields as var­ied as trans­port, in­dus­try, recre­ational sports, com­pe­ti­tion and aero­nau­tics. The com­pany’s know-how is to de­sign and pro­duce in­no­va­tive and ef­fi­cient prod­ucts with op­ti­mum man­u­fac­tur­ing qual­ity in the mod­ern world.

The pic­ture is of Pierre Cauquil in the 1982 Span­ish World Cham­pi­onship round.

Newspapers in English

Newspapers from UK

© PressReader. All rights reserved.