RE CLIPPER AIRFLOW .................................
Royal Enfield reckoned that their Airflow fairings would improve fuel consumption by 20% and add 5mph to a bike’s top end. Oily Boot Bob experiments with the elements and shoots the breeze…
Royal Enfield reckoned that their Airflow fairings would improve fuel consumption by 20% and add 5mph to a bike’s top end. Oily Boot Bob experiments with the elements and shoots the breeze…
An appreciation for comfort and practicality in a motorcycle has crept up on me almost unnoticed in recent years. I now find myself looking seriously at functional features and designs that I barely gave a second glance ten years ago, such as the Royal Enfield Airflow range, for good reason. It was squarely aimed at the sensible dad market sector, which I have seemingly grown into. The story behind a dramatic black and white photograph intrigued me, particularly as it unfolded only yards away from my workplace. The events took place thirty years before my arrival, where motorcycle and aircraft development very briefly overlapped.
The British defence industry suffered heavily from budget cuts during the 1950s, and had to diversify in order to survive. The Bristol Aeroplane Company (BAC) was keeping afloat by involvement in various civil projects such as motor car bodywork and prefabricated buildings, so it was business as usual when Royal Enfield approached Bristol Aeroplane Plastics Ltd, a subsidiary of BAC, for advice on automating the manufacture of their new glass fibre designs. RE’s chief draughtsman, Reg Thomas, noted that the production trials produced an excess of resin at the edges of the structure, which led to cracking. The time-honoured manual lay-up method resumed.
But the liaison with BAC was not in vain. With a foot in the door of the aircraft works, RE gained access to the air industry’s low speed wind tunnel to get some publicity photographs, and to test their new Airflow design which was already in full production. Royal Enfield was eager to be seen in the modern world of streamlined aircraft.
Mike, a retired head of the wind tunnel facility, takes up the story.
‘It’s actually secondhand information from over 50 years ago, but my memory is good. The tests were carried out by a colleague called Trevor Williams in the late 1950s. I joined them in 1961. At the time I was riding a Velocette Valiant with a fairing, which gave good protection from the wind, but I was not very convinced about its aerodynamic worth and it didn’t seem particularly nice in a strong crosswind. I was talking about it to another motorcyclist in the department, and how it might look in a wind tunnel test, when Trevor joined in and recounted the Royal Enfield episode.
‘ They (RE) wanted some publicity type photos in the wind tunnel of the fairing on one of their motor bikes, showing how well aligned some wool tufts were. You can get a good idea of the airflow over a surface by looking at the behaviour of tufts of wool with one end taped to the surface. We use something more sophisticated now, but it was wool tufts in the 1950s. Royal Enfield wanted to demonstrate how aerodynamic their fairing was, but the results were dreadful. They then wanted to tape the wool tufts down in convincing attitudes and take a photo. We refused to do this, because we didn’t want our good name involved with
such chicanery, and furthermore, I don’t think we ever got paid by Royal Enfield.’ Although the rider and bike are beautifully framed by the wind tunnel intake, the well-used image from the October 1958 photoshoot suggests that any idea of serious streamlining had been abandoned. With the bike perched on the centrestand, the huge front mudguard exposes a gape as big as a basking shark!
My own Airflow experience started with the offer of a fairly tidy and complete Clipper 250, the economy version of the Crusader, via the owners’ club network. Sadly, Peter Gay, an REOC member, passed away, leaving a large collection of Crusader parts and specials for his widow, Brenda to sort out. I was keen to try an Airflow in all the weathers of daily commuting and Brenda liked the idea of it being put to good use, so the deal was done. It came with paperwork listing the six previous owners, starting life at Jordan’s of Hull in March 1962. Unusually, the buff
logbook records early changes of owner like a hot potato – three in the first year. Did it not meet with their expectations? I wonder if ownership stabilised with the arrival of four more horsepower when a Crusader Sports engine was installed, apparently during this early period. The donor bike of the engine came from Shearsmith in nearby York. Recorded as a 1960 sale, it most probably became an insurance right-off shortly after.
I don’t think of the Clipper as a non-original bike, but instead an authentic rolling record of upgrades and preferences fitted to a budget motorcycle by the numerous owners over the years, and garnished with the scrapes and knocks of daily life. The Clipper had nonadjustable suspension struts, a fixed rear wheel (would that be slowly detachable?), unpolished cases and much reduced chrome plating to keep the price tag low. Since the speedometer is not original (a trip meter being outside the thrifty specification of the Clipper), the mileage of the bike is unknown. Fitting a trip-equipped speedo isn’t an entirely practical modification. Resetting the
trip toggle requires some dextrous groping through the ‘cubby hole’ – RE’s own name for the void behind the dashboard.
Wheels from one of the sports models have been added to benefit from an extra inch of bite over the feeble 6” brake at the front, and a quickly detachable hub and wheel at the rear. This QD wheel has to be one of the best of the period, whose cast iron heftiness is easily outweighed by its detachability. A few turns of a 9/16” spanner will have the wheel out in a few seconds, leaving the chain, brake and cush drive undisturbed.
The most recent addition is the fully enclosed chaincase, painted and installed by the seventh owner. One of these rare as hen’s teeth extras came my way shortly after buying the bike, an opportunity not to be missed. This two-piece pressing connects to the engine unit with rubber gaiters, completing a sealed environment against rain and road grime. Consequently the bike remains free from the usual mess of far-flung chain lube. A rubber bung is removed from the upper run to perform lube duties, and only the semicircular rear section needs to be disturbed to remove the chain. With a quality German chain installed, I expect to make adjustments about once every leap year.
Avon Universal tyres were the choice of the sixth owner, and a very good choice too. They’re old but usable. With a similar tread pattern to the old style Roadrunners, they were quite the best tyre for the limiting 17” wheels, and it’s a shame they are no longer made.
The Clipper is dressed in the middle size of the three fairings made to fit the complete range of Redditch motorcycles; there was even one to suit the little RE125. Fixed in only three places, the fairing is extremely rigid and so quite heavy when compared to contemporary universal fairings. Crazing of the paintwork is evidence that the bike has tumbled on its side a few times causing the bodywork to flex but not break. But quickly removable it is not. The front wheel must be removed followed by the fork sliders in order to slide the enormous mudguard down over the fork tubes. Only then can the fairing be lowered away. This apparent oversight was deliberate to minimise the size of cutaways in the glass fibre to keep out the bad weather. Thankfully accessibility is good enough to perform even major engine work, making fairing removal unnecessary. So what is it like to ride? The low first gear often criticised on the sports models becomes an asset on the Airflow. It’s extremely useful for getting the extra 25lb of fibreglass moving from a standstill, particularly if you’ve stopped on a gradient. Sixty years after its conception, the benefit of such gearing becomes apparent in urban congestion where one can dribble along with the clutch fully engaged and be overtaken by dog-walkers.
Sitting behind the screen and dashboard on the 29” high seat gives a reassuring feeling of being inside a cockpit, rather than astride a motorcycle. The contoured and very comfortable dualseat is the obvious combination of a single saddle and a pillion seat cushion, providing full backside support, which isn’t too sunken to prevent rearward shuffling for leg stretching purposes. Obvious comparisons with its closest competitor, the Ariel Leader, didn’t occur to me until several weeks of riding had passed. That’s strange, since I covered thousands of miles on one as a teenager. I can only conclude that the ergonomics are very different.
The height of the Airflow’s screen complies precisely with the popular rule of thumb – level with my nose – which sends the prevailing wind and any airborne elements
well clear of my face, allowing me to ride with my visor fully open if I wish. No head buffeting is experienced at any speed. Top gear can be engaged just beyond 30mph on the flat, while the extra weight forces the prolonged use of second gear on an incline. That weight needs to be rolling at cruising speed before the subtle aerodynamic advantage takes over. With almost as much windage as an ocean-going clipper, the Airflow is sensitive to the lightest breezes. The bow wave of a passing car is felt long before it appears alongside, causing that momentary sensation of being grabbed from behind.