Doug Reynolds: 50years of Model Engineering Excellence

By now he had a son, John and daughter Janet, but he was to see nothing of them for a further 4 years as he was transferred to the Royal West African Frontier Force, serving in what is now Nigeria and Ghana. Following his demob, he returned to Aerolex and began his long involvement with model engineering. Space was very limited and he overcame this by installing a 3½ in lathe in his son’s bedroom and starting work on the first of the projects that were to bring him such richly deserved recognition over 50 years later.

Whilst the part count for the new 30cc motor was low, the design was to reflect the very latest practice in high performance engines. The rear rotary valve, loop scavenged engine was very compact with weight kept to a minimum. The crankcase with its large bypass was essentially a sculpted block with front and rear housings, cylinder and cylinder head bolted on. A downdraft venturi with a strangler and a conventional needle valve got the fuel into the motor while a single manifold and silencer took care of the exhaust.

Some notes do exist relating to the development of the engine.

"Test run made on Nitro Methane Methanol 10% 65% 25% (oil)" "Rotary valve too much overlap new rotary valve made." "New cylinder head fitted, new piston made of cast iron shell with thin sleeve of Duralumin. Deflector top." (An unusual feature was that the deflector was curved to match the piston, rather than straight as on commercial engines.) "Engine performance well improved on old piston also easier starting. Note Glow Plug needs to be set close to piston at TDC to retain heat".

Running the boats RTP usually took place at Fleet Pond, the home of the Aldershot Club, where Jim Bamford who was to became a lifelong friend was registered as AT1 and Doug as AT2. Before a pylon was installed, it was son John’s happy lot to have to stand in the middle of the pond acting as the tethering point. Engine testing was slightly less fraught but an even wetter experience. The boats were run up, either in a tin bath in the garden, or in the adjacent local river, where Doug would fire up the motor with the boat between his knees and wind it up to full revs with John strategically placed at the bow in case the boat escaped.

Although the boat was destroyed at some stage, the engine from Triton 3 survived. Having retired in 1984 Doug was heavily involved in other pursuits, but returned to his modelling roots in 1992 by systematically working through all his surviving boats and engines, reconditioning as required, making changes where he considered it desirable and bringing all the motors back to good running order.

Throughout September 1992 the 30cc motor underwent major surgery to try and address some of the problems that had been evident in its early days. After an overhaul, a new piston with a conventional deflector was fitted along with alterations to the head to match. Several experiments were tried with differing positions for the glow plug and eventually a completely new cylinder head was machined up.

Whilst on the two-stroke theme Doug produced two more racing engines, one for the 15cc ‘B’ class and a 10cc for the ‘C’ class. Jim Bamford, his club mate and friend, devoted much time, energy and effort to producing competitive flash steam hydroplanes as well as competing with IC engined boats. The most successful of these was ‘JAB 3’ with a George Lines inspired engine. The George Lines rear rotary valve ‘Sparky’ motor was by far the most successful 15cc engine of the time and won innumerable races as well as becoming the most copied engine in hydroplane history. Doug Reynolds set about building a similar motor and for once he mirrored the techniques used on the original as that too had been machined from the solid.

The 10cc motor is a very different matter. Whilst the 15cc class was dominated by engines based on the ‘Sparky’ design, the ‘C’ class was the province of the American Dooling and McCoy motors.

These were very fast, but expensive and difficult to obtain and the Dooling in particular was very fragile, as its die cast crankcase would easily blow apart if it took in any water. Many competitors set about building replicas of the Dooling and some of these were very successful, but they did require complex patterns and cores for the castings. Continuing with his normal method of production, Doug Reynolds machined his Dooling replica from the solid and overcame the difficulty of reproducing the bypass by using a technique from the past. Instead of special tooling and machine set ups, the transfer passage is machined into a separate piece of material and then bolted to the side of the engine. With a steep downdraft venturi that puts the fuel straight on to the big end this was a very handsome engine.

This hull for the 10cc motor represented a radical departure from the style Doug had been using as can be seen from this photo. As well as sponsons, there is a secondary step behind the engine, which is most unusual. Judging by the large weights bolted to the transom the boat was lifting too much at the rear end. During the early 1960s,new hulls were constructed for the 10 and 15cc two-stroke engines.

Both hulls are reminiscent of the later Lines designs that dispensed with a skeg and had an after step with the prop shaft coming out through the transom. Towards the rear of the deeper 10cc hull can be seen an aluminium fin that aids the boat getting away by counteracting the torque reaction from the prop. This was a modification that was used on several of his boats. No bungee launches for Doug in those days! During 1996 this engine also had a bit of a make over with a new venturi and needle valve being fitted. A large lump of lead on the transom of the 15cc boat indicates that the back end was somewhat 'lively'

If you consider that this represents an incredible output, with everything having to be machined from the solid there was yet another major engine building project, a 30cc overhead cam four-stroke for an ‘A’ class boat. Although this engine was again machined from the solid it shared little in common with the previous 15cc OHC motor. The crankcase was split vertically and very short allowing a very short and stiff crankshaft to be fitted. All the other engines he built had overhanging cranks, but for this one a twin flywheel motorcycle crank was constructed. The camshaft was chain driven with the 2:1 ratio sprockets being hand made and the rocker arms using ball races as cam followers. Most unusual for an engine of this size was the piston which was lapped cast iron. This compromised the combustion chamber shape somewhat but was probably done for expediency as one of his work colleagues at Aerolex, Ted Barton, was a precision grinder, and in a recent conversation he recalls grinding and honing several cylinders and pistons for Doug.

The engine was mounted in a 34½" long hull with outrigger sponsons. These were later removed and adjustable aluminium side planes fitted, as on Triton 2. Several modifications were made to the engine during its life, including a range of different venturis, needle valves and jet arrangements. The hull suffered the ravages of time, but in a joint effort between Doug and son John an exact replica was built and a jig constructed so that the engine could be run on dry land. The engine was also given some attention at this stage and another twin jet R/C type carburetter made and fitted to give better throttle control than a needle valve. Along with the notes detailing the work on the engine is a calculation and admission that with the bore and stroke dimensions chosen; the engine is around 25cc and not 30cc as originally indicated.

From a modern perspective it is very difficult to understand how so much time could be devoted to building engines and boats as well as all the development that went on besides, but it seemed to be the norm for the enthusiasts of the period. Doug’s output was not unusual in the tethered boat world and is indicative of the way the balance between employment and free time has changed over the years. Racing was so much more than just the boats and engines as the very best were no good without props and making these was an essential skill for any competitor.

This almost concludes the story of the hydroplanes and engines, but as mentioned in the introduction Doug Reynolds did not confine himself to hydros and IC engines, although how he found the time is remarkable. While still working on Triton II, the 30cc two-stroke engine and Triton 3 in 1952, he embraced another discipline, that of tethered cars.

Tethered car tracks were becoming rare and so Doug improvised by using an area of road outside his home. As he did not have a pylon, his son John was deputed to hold the line, control line style, while the car sped round. Perhaps John could then appreciate why the Americans called tethered cars spindizzies. As with the boats, the car was also subject to rethinks and development and in the course of the year a recoil starter and clutch were fitted, and the engine was converted to glow plug ignition. With these changes the car was capable of 55-60 mph, but I suspect that lack of a track caused the car to be put away in the shed at the end of the year.

The car was to stay there, untouched, for a further 40 years until in July 92 it was ‘taken down to be looked at’. The engine was gummed with castor oil and rusted so it was stripped down, as was the chassis. It was discovered that the self starter clutch was broken so the engine reverted to a centrifugal clutch and hand starting. "The engine started in about 20 pulls but would not keep running." A number of faults were identified and rectified including the left hand rear tyre parting company with the wheel when the engine got on to full song. Whatever Doug tried though, the engine would only run with the glow battery connected and after a series of frustrations put the car away to concentrate on refurbishing the 30cc boat engine.

Interestingly, amongst the various drawings were a set of Atom 5 blueprints, but on the reverse were plans for a 30" hydroplane hull showing the car engine installed. It transpires that this was the original plan for Triton 1 and the engine was built to go into this boat, later being transferred to the car.

What might seem odd is that there are numerous references to speeds, performance and technical details relating to the boats and engines, but never any reference to competition. To Doug Reynolds it was the design and engineering challenge of the hobby that was important, and while he did attend regattas it was as an observer constantly looking for ideas and ways to improve his own boats and engines. When the Fleet Pond was lost in the late 60s, the boats were put away and he turned his attention, skills and sense of purpose to other areas, until his interest was rekindled in the early 90s.

Vigorous tugging on the starting cord produced nothing except a reddening of the face. Yes there was fuel, but as the tank had sprung a leak the contents were slowly draining into the hull. What about the plug and a glow? Ah no glow, try spare plugs, dead, take one from another engine, yes a glow, well more like a sunspot for a second or so and then a stark realisation. The battery was not a Nicad so it was knocking out 2 volts and knocking out plugs with equal speed, so with our tails between our legs we retired for a cup of coffee.

Not being able to face fighting our way through the local football supporters for a return trip to the model shop we reluctantly gave up the idea and set to photographing and recording the whole amazing collection. Considering that all the engines, boats and the car that are illustrated and described here and all the development that were done on them, originally occupied no more than eight years is a testament to the skills and unremitting hard work that Doug Reynolds devoted to his his modelling.

OTW is extremely grateful to John and Jackie Reynolds for their hospitality and our thanks go to John for all his help, advice, reminiscences and for sharing the collection and information with us.

Doug Reynolds - Update   The recent discovery of Doug Reynolds’ photo album has proved a most exciting ‘find’. Not only has it provided original photographs to add to the existing pages, but more importantly it has provided vital information about the development of each of the Triton boats. The photos, helpfully captioned and dated, have also identified more hulls in the series that were previously unknown, as well as more fascinating material about Doug’s general involvement with model engineering and tethered hydroplanes.

Thanks to John Reynolds for the loan of this fascinating archive of photos and cuttings.

 CopyrightOTW 2007