Cycle News - Archive Issues - 1990's

INJHE.. PADDOCK·. . .: '. .: BM y ichael .Scott he Spanish Grand Prix at Jerez was well-ehosen for the debut of Aprilia's new giant-killing 400cc V-twin. Of all the tracks on the GP calendar, th e Andalusian jog puts the emphasis on hard braking for mainly medium-speed comers, with straights not long enoug h for the factory 500s to reach 170 mph, some 85 percent of their potential. In this territory, an agile bike with only a reasonable amount of poke can circulate close to the ultimate possible lap speed - as can clearly be seen from the fact that, yet again, the top 250cc qualifying time would have pu t its perpetrator, a rampa nt Honda-mounted Loris Capirossi, well up on the second row of the 500cc grid. He was faster, in fact, than Loris Reggiani , on th e "super-250 ", though th e yo u nger Loris was the on ly one of his tribe. Loris the Elder, on the prototype RSV400, was there on the second row of the 500cc grid - in the bike's first outing. He wen t on to a top- 10 finish that was somewha t fort uitous , for as predicted, the little twin couldn't match the factory V-fours . And if the two Yam ahas of Luca Cadalora a nd Daryl Bea ttie hadn't retired, and Shinichi Itoh hadn't crashed out, Regiani would und oub ted ly ha ve been two or th ree places lower. Bu t it was eq ually significant that only one of the non-works V-fours had beaten him tha t ridde n by the redoub ta bl e N iall Mackenzie. An d all this was on a bike in a delibera tely low s ta te of tu ne for re lia bility, yield in g only l O S-od d of the p lanned pea k of 130 horses. Detailed stu dy of th e bike' s performanc e is revea ling, and not entirely as expected . The organizers obligingly produced official section tim es for the last and fa s tes t practice. The first s ecti on included both of Jere z' s short straights; the second was from a hairpin through a medium-speed section; the third through th e daunting fast rights then into th e closing hairpin. Each in its way offered a different type of going. One might have expected the Aprilia to fare worse in the firs t fas ter section, and better in the twistier pair. Not so - all best section times were more or less in line with qualifying positions. (Best section times, of course, do not necessarily come in the same lap.) Reggiani was seventh-fastest through the straights , eighthfastest on the twisty bits, and qualified seven th -fa s test overall. By the same token, Kevin Schwantz was consistentl y the fastest through all sections, and qu alified on pole. Speed-trap times were not SO use ful because the trap had been set up too far T down the straight. At this point, Reggiani would be still tucked in and on the pipes, but the guys on the really fast bikes, with a load more speed to lose, were already sitting up and aiming for the brake lever. For this reason, it was Al ex Ba rros ' s Suzuki at the top rather than one of the clearly- faster Hondas - the Brazilian is known for his demon late b raking. For the same reason, the speed differentia l may have been higher had the trap been a few yards back. Reggian i' s to p-10 speed was 156 mph, while Barros ha d whistled through at 167.6 mph. In fact, Reggiani's speed was much more in line But this is just a side issue. The real challenge of the V-twin is against all the V-four generation, for there is no question but that the breed is currently stagnanl Lap records for the SOOs, when they co me a t all, are b y hundredths more often than tenths. Several still stand from 1992; Malaysia fro m 1991! During th e same period , benefitting from similar tire development, the 250s and 125s ha ve been slashing chunks off their rec ords, th eir lap times n osin g up among the fastest SOOs at tracks like Jerez. The single common ingredient to all tea ms is the arrival of the rid er-friendly with tha t of the faste r privateer V-fours. This w as also in line with on -track observations. Schwantz took the trouble to follow Reggiani, and admired a mid comer speed "far faster than I could hope to carry," but added: "It was no problem to blow by and get four or five lengths on the straigh ts." John Reynolds also tagged on behind, but found th at hi s non-w orks H arris Yamaha was unable to perform the same trick. He felt himself getting sucked into the comers faster than his bike co u ld manage, and was forced to let Reggiani go. Re yno lds, along with Mackenz ie, Sean Emmett, Jeremy McWilliams, Bernard Garcia and Laurent Naveau, rides a top privateer Yamaha, with a bigbang engine and a frame hardly too different from the Roc unit used by the factory team. The fact that the Ap rilia had their measu re serves to illustrate, if an ybody didn't know already, how wide is the remaining gulf between a real works Yamaha and a close copy. It is a matter of trick everything: motor, suspension, fuel, and most importantly, tires. These little things add up to a significant difference that makes Mackenzie's Jerez ride to a fighting eighth all the more impressive. Big Bang close-firing-order engin e. These lack the exp losi ve burst of the earlier en gin es - which gave blazing lap times but left tires and nerves shredded - but th ey relia bly yield faster averag e race tim es by better p reserving both rubber and rider. But this is not eno ugh, in itself, to explain the lapse. It's more tha t the V-fours have run up against a brick wa1l. They are too powerful, obliging them to wear over -wide rea r tires that hinder their tracking through the comers and drop comer speed. These engines a lso n eed large radiators, th at d rag through the air like the proverbial bam door at higher speeds, requiring yet . more po wer for any progress. This last factor is further aggravated by the one-size-fits-all streamlining dictated by the rules. The "dolphin" fairing d at es back to 1958, a nd was imposed after a number of accidents were blamed on the reaction of dustbin fairings to cross-winds. rlns tea d of encouragin g designers to make a better dustbin, they were banned a nd rules drawn up that still dictate the stubby bodywork of a modem GP racer. (Improvements to the r u di men ta ry streamlining are now sought by sewing foam-ru bber hunchbacks in to th e riders' leathers. Bizarre, really, when the goal of engineering s hould be towards refinement and efficiency rather than perve-club prosthetics. Pe rhaps strap-on bottom-fairings will be next, or even Silicon buttock implants. The rules forbid bodywork from extending much beyond the back axle lin e, but there's nothing said about the rider's anatomy.) This illus tra tes the case. It is the rules that dictate racing bike design, not an y engineering ideal. It is the rules that created the Aprilia 400 too. The Italian firm's chief d esigner Jan Witteveen is quite open. "I was a big sup porter of the rule change that allowed a lower weigh t limit for a twin, because I had the id ea of th is bike in my m ind alre a dy," sa id th e Italy-ba se d Dutch en gineer, who served two-str ok e time with Gilera off the road before making a GP w inner for Ap rilia based on the discvalve Rotax engine. In pro totype guise, the challenger is over the minim um weigh t limit by some five kilograms - the limit is 100 kg (220 lbs.) to 130 kg (286 lbs.) for four-cylinder bikes - as well as below targe t power. In this form, runnin g between the works and private V-fours was a strong debut, even given that the track suits its nature. Things will surely be different at the next two tracks, the fast Salzburg ring and Hockenheimring, where al most any Vfour running on all cylinders should find that the territory above 156 mph is theirs to play with . Asked how they would mod ify the bike for these tracks , Reggiani joked: uWe will p ut more screws in the fairing, so it doesn't get blown off as they come past," With its di sc valves, the Aprilia is well-suited to crankcase fuel injection - it jus t needs somebody to develop a system. Honda's now-withdrawn PGM-F1 is really a glorified electronic carburetor, and they have, in an y case, withdrawn it for the present. Disc valves, however, can be tricky at part throttle, coming onto the po wer more bru tally than the reed valves used by all the V-fours. And since 500s spend almost all their time at part-throttle, th is could dent the Aprilia's advantage of being easier to ride. . There is something more im po rtan t, however, in the forthcoming battle. The Aprilia did better in practice than in the race, in sp ite of being helped by retirements. A clean fast lap is one thing, mixing it wi th bigger bikes that are faster in a straight line - and in your way through the comers - is quite another matter. And while the first rival to the d ominant Vfou rs scored a d ir ect hit in its sha kedown r un, th at hurdle will al ways ~ remain. 1 : ·:· LObi

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