AERMACCHI CHIMERA................................
Sleek and super-snazzy, this Latin lightweight stole the limelight at its launch. Which just goes to show that the motorcycle press knows absolutely nothing about what the public wants to buy. Rowena Hoseason finds it has considerable classic kudos, howev
Sleek and super-snazzy, this Latin lightweight stole the limelight at its launch. Which just goes to show that the motorcycle press knows absolutely nothing about what the public wants to buy. Rowena Hoseason finds it has considerable classic kudos, however
‘These days it’s considered magnificent,’ says owner Basil Keir, who might be a tiny little bit biased when it comes to the Aermacchi Chimera. He loves its ‘stunning looks and futuristic styling’ but freelyy admits that ‘it wasn’t acceptedp byy the Italian public’ back in the 1950s. Machines like the Chimera still divide opinion today but there are enough enthusiasts around to ensure that any which come on the market are rapidly snapped up. Indeed, Basil paid… well, ‘too much’ for his 175. But most classic bike enthusiasts wouldn’t give you tuppence for such an unconventional contraption – which is a shame, because there’s some solid and innovative engineering lurking underneath that jet-inspired styling.
The Chimera came in two capacities and was built in tiny numbers between 1956 and ’64. There were less than 300 manufactured, just 119 175s and 177 250s. Which means that you’re more likely to fall over an ohv Brough Superior SS100 than you are an Aermacchi Chimera. Talk about rare!
Along with many European motorcycle manufacturers, Aermacchi concentrated on lightweight commuter machines to get them into the post-war civilian game. They’d been building aircraft for four decades and needed a non-military
market for their engineering expertise. Two-wheelers looked like a solid bet in the austerity-driven post-war economy, and their first two-stroke semi-scooter arrived in 1951 after one of Lino Tonti’s designs caught the management’s eye at a trade fair.
Tonti didn’t stick around at Aermacchi for long,g, and the head designer’sg desk was soon filled by Alfredo Biancchi (who was also responsible for the Astoria aand the Parilla). The Chimera was Bianchi’s fifirst project for Aermacchi and it was also the firm’s first fourstroke motorcycle. While Biaanchi handled the mechanicals, stylist Mario RRevelli attempted to unite form and function, aiming for a ‘perfect fusion of industrial necessity and aesthetic grace’ (that’s a verry loose translation from a contemporary Italiann interview). Revelli, an ex-GP bike racer and car stylist, produced a sketch of his ideeal motorcycle, and Bianchi built a bike around that concept.
The finished machine cerrtainly wowed the crowds at Milan. Period pubblications extolled its smooth, flowing design aand considered the Chimera to be the ‘peakk of engineering elegance.’ The Motor Cycle ppositively gushed about how ‘the daring origiinality of line and construction are refreshhingly free from conventional ideas.’
Underneath the striking eexterior, however, lurked an almost eentirely orthodox ohv motor. The 60mm by 611mm, unit construction engine used vvertically-split, aluminium alloy crankcases which provided part of the visual impact; a built-up, roller bearing big end, cast iron barrel and an aluminium cylinder head. Super-sportsters of the time were equipped with overhead cam engines, but Bianchi opted for a pushrod design – cheaper and easier to build, simpler to maintain and more durable for everyday duties.
Bianchi used helical gears to transfer the primary drive – no problem for an industrial aeronautical manufacturer, familiar with working to extremely tight tolerances and tooled up to cut precision gears. Then power was conveyed through a wet, multi-plate clutch to the chain final drive. The kickstart was situated on the left while a right-side, heel-and-toe lever selected ratios in the fourspeed gearbox.
The compact motor was horizontally inclined – establishing a future hallmark of the marque – which meant that the cylinder head faced forwards. ‘ Two of the biggest problems facing the designer of an enclosed model concern engine cooling and accessibility,’ commented The Motor Cycle. ‘Both have been expertly tackled… cooling air enters the open front of the die-cast aluminium alloy engine cowls and impinges directly on the cylinder head. No amount of hard riding produced the slightest symptom of overheating.’
The engine layout also carried the motorcycle’s mass as low as possible to enhance the Chimera’s handling. This appears to have been successful, as owners report that the Chimera corners like it’s a little rocket on rails. The styling hides another of its assets; an early form of hydraulically-damped monoshock suspension with a single rear spring tucked away under the saddle. This, at a time when many motorcycle manufacturers were still selling their lightweights with plunger rear suspension – or no rear suspension at all! Apparently, Aermacchi tested their chassis for months during the model’s development to ensure that the frame would withstand the rigours of regular riding. Motor Cycling reported that ‘huge cams pumped the suspension, and other little devices applied stress at such points as the steering head. It brought out initial weaknesses in the rear suspension spring but I was assured that at no other time had the frame itself failed.’ As confirmed by owner Basil: ‘ The rear suspension is quite advanced for its day and gives it nice handling compared with British contemporaries of similar size.’ The front end appears to be fairly conventional with a pair of telescopic forks, although all the control cables and the handlebars themselves are hidden from sight by a quickly-detachable nacelle (easy for the home mechanic to remove for access to adjust the steering head bearings). But the heavily-valanced front mudguard is anchored to the lower yoke rather than to the 17-inch front wheel, so the wheel moves towards the guard rather than the pair moving in tandem. This was odd enough to discourage
some buyers at the time, who didn’t like the gap between the wheel and the guard – necessary for soaking up bad bumps on Italian byways.
And if the front end arrangement dissuaded the casual browser, then you can bet they weren’t at all inspired by Revelli’s jet-inspired styling job. Like the Ariel Leader (and most scooters) it attempted to ‘clean up’ the motorcycle’s appearance. Everything had to be uncluttered and sleekly sculptured. All the untidy mechanical aspects – cables, oilways, fuel pipes, drive chain and even electrical equipment – had to be hidden from sight behind the sweeping pressed-steel enclosures.
This might seem to be a radical notion, one which conflicts with the understanding that most motorcyclists are interested in the engineering that underpins their form of transport. Classic riders in particular tend to like looking at their engines. But if in the 1950s motorcycles were to become mass transport, so the reasoning went, then they needed to be less mechanically intimidating. And a lot less oily.
Hence the fashion for full enclosures as adopted by most British manufacturers, and Ariel’s full-scale pursuit of a mainstream market that never developed.
The Leader and its ilk were left high and dry… well, until three decades later when another generation of designers would do this all over again with the Ducati Paso, Morini Dart and Honda’s CBR600F. They also attracted a fair amount of flak from motorcycle enthusiasts…
Mind you, the Chimera always had a solid core of admirers. It still attracted favourable comments in the mid-1980s when Cyril Ayton, editor of Motorcycle Sport, was surprised to note that the Chimera’s bodywork ‘contrived to look rather elegant… sleek and gentlemanly.’
You can certainly see the jet-engine inspiration in the way the two cream centre-sections meet under the petrol tank at the front of the machine to enclose the horn. The red trim around the aluminium engine casings definitely brings a sense of the streamliner. Think De Havilland Comet and you probably get the sense of what Aermacchi were aiming for – minus the metal fatigue, of course.
Nor was the Chimera an impractical proposition. The bodywork, like the instrument nacelle, was designed to be rapidly removed for regular maintenance. Owners of a fully-clad Norton Dominator Deluxe might wonder how on earth they could flood the carb, but on the Chimera all the necessary openings and apertures were designed in to the pressed steel panels, which also housed a three-way petrol tap and a lockable toolbox.
The Aermacchi’s spark plug was positioned towards the front of the combustion chamber at an angle, so it could be extracted using the long spanner supplied without removing the engine cowl. Likewise, you didn’t need to strip off the bodywork to get at the engine oil dipstick or contact breaker points. The standard equipment even included a type pump.
The Chimera could also clip along at a reasonable rate for a motorcycle which carried a lot of pressed steel around with it. The 175 started out with an 18mm Dell’Orto carb; the 250 ended up with a 22mm item.
The 13bhp produced by the 175 engine gave it an absolute top whack of 68mph and the ability to cruise at 60 for extended periods. The 250 version, equipped with different gear ratios but otherwise much the same as the 175, could just about touch 75mph – which put it ahead of Ariel’s two-stroke Leader. In part that’s because the Chimera weighed around 25lb less than the Leader. And once you stripped away more of the mass, as Aermacchi did in the years that followed, the 175 and 250 engines more than proved their mettle as lightweight racers. When it became obvious that customers weren’t stampeding to the showrooms, Aermacchi re-worked the Chimera to produce a range of more conventionallooking dual-shock roadsters with classic café racer styling. The 18bhp Ala Verde 250 ran slightly higher compression than the Chimera, and was equipped with a dual, 8-inch front brake to match its 80mph performance. Even so, Aermacchi’s venture into motorcycle production didn’t bring the commercial success they’d sought. Enter HarleyDavidson who bought half of Aermacchi in 1960 – and so the spirit of the Chimera lived on in the Sprint 250 and then 350. A later development even enjoyed success on the Isle of Man, finishing second in the Junior TT in 1969 and ’70.
The Chimera continues to wow a certain segment of the classic world, and its prices reflect its rarity. While £3000 will buy you a fully restored Ariel Leader, that’s the lowest possible price you’ll pay for a barn-find Chimera (if such a thing actually exists), missing some components and in need of a complete overhaul. Engine and ancillary spares aren’t hard to come by, but you’ll need a bodywork whiz to bring its panelling back to perfection. Or you can scour the sales – when an immaculate 1958 175 was offered at an auction in London last year, the asking price was £15,000. Please don’t choke on your chips.
Looking at the photos of this imaginative experiment, I can’t help wondering where we might be today if yesterday’s motorcyclists had embraced such a bold vision of tomorrow. What would our 21st century motorcycle be like, if the innovators and engineers of the 1950s had been rewarded by commercial success? We used to dream of riding jet-bikes across a clear blue sky – but instead we bought BSA Bantams and remain firmly earthbound.