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Pic 1, Pic 2, Pic 3, Pic 4, Pic 5,
Pic 1 to 3: These are pictures of an early model Merco 61 sent in by Malcolm Stride, a ME Contributor. The engine needs a thorough clean, but other than that would appear to be ready to go after many years in storage. Pic 4 & 5: Two fine close-ups of the cylinder head and carburettor, again supplied by Malcolm Stride.

Yes guys, itís flash bang month again! From last monthís mixture of reader sourced material, I now move back into familiar cc (cubic capacity) territory - the model engine. It may seem strange to say so, but you would think after so many years in these pages, that there could be no aspect of vintage model boat power that I could have missed, but that would not be so. Weíve delved into petrol and diesel, electric and steam, pop-pop, clockwork and even rubber, but the reason is simply that I write from hands on experience back in the 60ís - 70ís era of straight running and r/c boating and no one could do or own everything.

For one thing, I only ever once built a tethered hydroplane (unsuccessfully I freely admit), and only rarely used glow power, preferring to stick with English made diesel and petrol engines for which spares were quickly and mostly affordably available over the counter in local model shops. Yes of course, there were English made glowplug marine and aero two strokes available in my period at the pondside and well before that even, Frog and ETA for example, but by the 70ís most glow jobs were Japanese, German, US or other imports, for which varying degrees of service and spares support were available.

Letís start with Super-Tigre, Merco And O.S. engines

Other than for the rather exotic Italian Super-Tigre, which always had a name for rapid spares availability through World Engines at Watford, spares supply could be distinctly patchy, but never the case with simple home market diesels like E.D., DC/Allbon and Taplin. A British glow range that always enjoyed the very best of spares and service availability was Merco. During the 70ís, I had an r/c flying friend who was also a garage mechanic with lifelong experience on full size i.c. engines ranging from motorbikes up to and including armoured fighting vehicles. Yet he flew only Merco 61 (10cc) engines in his planes, because of their relative reliability and good spares availability and whenever the model shop I helped out at in those days (John and Jean Hainís Essex Models and Hobbies - EMH in Westcliff-on-Sea, Essex), tried to interest him in something new, heíd always say ĎIf I have a problem I want to be back up there the very next weekend - try that with your latest fancy Jap or German importí. There was a lot of truth in it, especially here in South Essex as Merco (and O.S. as well to be fair) spares were always quickly procurable via your model shop from Keilís at nearby Wickford.

Amazingly when you consider how common they once were, after all these years I had some difficulty finding a decent 49 or 61 size Merco until I contacted Model Engineer i.c. engine columnist Malcolm Stride, who just happened to have an old one and I am thus able to show you his own Merco 61 Marine.

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Pic 6, Pic 7, Pic 8, Pic 9,
Pic 6: Mid fifties advertising for the ETA 29 (5cc) racing glowmotor, here in Mk. 6C format from an advertisement in Aeromodeller. This engine was still hugely popular in 5cc tethered hydroplanes and r/c speed models in the early 1960ís. Pic 7: The earliest ETA 29 test that I could find dates from 1949. It is interesting that the only grumble the reviewer could rake up, was to say that low speed performance was not so good! Remember this was a racing engine and got better and better with development. Data from Engine Tests of Yesteryear by Geoff Clarke. Pic 8: The Merco engines were the biggest selling and most popular British glowmotor range of my period in modelling, whether in the air or on water. Sizes of 5cc up to 10cc were available. Pic 9: The Japanese OS (and ENYA) glow engine ranges imported into the UK by KeilKraft and Ripmax were the first to pressure UK manufacturers. The OS 30 (upper right) is the engine referred to in the text. Picture from KK Handbook c1970.

29, 35, 49 and 61 Mercoís

Designed by Ron Checksfield with later involvement by Dennis Allen, the Merco 29 and 35 duo, presaged the bigger 49/61 by a few years and enjoyed a period of popularity in control line aerobatics (stunt) and in early multi channel radio control aircraft classics like Chris Olsenís Uproar as well as being watercooled for use in boats a little later. There were two versions of each with a basic spraybar venturi for control-line stunt use and with an r/c throttle and coupled exhaust clapper for radio control. For a time, these two were the biggest and most popular aero engines in the UK, the 35 being simply a bored out 29. The Merco 49 however was a brand new, top-of-line 8cc design, driven by a fashion arising in the USA for larger and heavier r/c aerobatic aircraft and this in turn, was quickly bored out to give the even more powerful 10cc Merco 61, that in itís ultimate twin plug form, became almost a standard choice fit in the club level radio aerobatic and scale aircraft of the 1970ís and in fast boats when water jacket, silencer, and flywheel equipped. Talking of silencers (mufflers), Merco always had these available (smartly engineered and well cast they were too), as well as simpler exhaust stubs for the marine versions.

Looking back, itís easy to see that the fast revving and mostly imported glowmotor, was already edging out the domestic diesel from about 1967-70 onwards, but this wasnít so easily perceived in the boat world back then. In r/c aircraft yes, but not in boats where the lower weight and higher revolutions of glow engines were not so obviously beneficial. One saw over the model shop counter that the divide was very obvious. Once past the trainer stage, even a club level r/c flyer was buying a Merco for aerobatic and sport and maybe a hot racing imported 40 for a Goodyear style pylon racer. Mr. Ordinary Boater however, mostly clung on to the 2.5 - 5cc diesel he was used to and Mr. Big Boat kept to his Gannet or Taplin-Twin in 8cc or 15cc sizes. However, the better off and more far sighted on the regatta circuit were trying out a Miles, ETA, or Merco glowmotor in lightweight cut down GRP flattie racing hulls and the big performance increases they were getting, even in club level races, were only too evident to those of us who were maybe a bit more conservative. For a while though, glowplug engines were not always great news. For one thing, few were available with proper water jackets and silencers and fast boat modellers were obliged to use makeshift ideas like coils of copper tube sprung around the cylinder fins. Also, one was quick to notice that hotshot glow powered racing boats often cut out after just a few laps allowing Mr. Plodder (yes, thatís your writer ) to sometimes win the day with his slower, but utterly reliable diesel or petrol powered wooden cabin cruiser. However, on a good day, Mr. Glow would certainly see you off with great ease.

I never afforded anything as powerful as a Merco myself, preferring the smaller and more easily transported hulls that came with 2.5 - 3.5cc diesels, though in my later, better off years in r/c boating, I did build a few bigger hulls for second hand Taplin-Twin and Gannet engines that I briefly owned, but my best and happiest times were undoubtedly running medium size, single cylinder diesels like the E.D. Racer, Hunter and especially, my favourite plodding Sea Otter, in hulls like Vic Smeedís Cachalot. While fast-ish, these were not exactly cutting edge, so I was therefore never anything like in the top three, but many happy hours were had all the same.

I guess thatís from where my antipathy to these big, noisy glow engines stems. I watched so many folk struggle to start them using dead or dying dry batteries, duff glowplugs (the man in the model shop never said you needed a spare), wonky or broken glowclip connectors, almost always with much too thin a gauge cable giving a big voltage drop, or stale and water polluted fuel. To make matters even worse, if such were possible, from the 1970ís onwards, many serious race boat enthusiasts started going in for electric starters, ammeters and electric fuel pumps housed with large, impressive looking toolkits, big 2, 6 or even 12 volt batteries and gallon containers of fuel, in elaborate field boxes aped from those seen at the flying field. The model trade loved this of course - so many gizmos to sell! All this unnecessary technology seemed to me to be far more trouble to cart down to the lake than it was worth, once one got there. So a medium sized diesel, a starting cord and a pint of KeilKraft or E.D. diesel, remained my uncomplicated choice and I was not alone in staying low tech.

As Dave ever so reluctantly went glow!

So just what is my experience with model glowmotors you might reasonably ask? Well, err, um, not so much really! For a few years I owned and raced an O.S. 30 (5cc), in a fibreglass E.D. Krak-a-Long and found it reliable, if not that much more powerful than Viking and Sea Lion diesels of the same capacity, though that O.S. was certainly more pleasant to operate from a vibration point of view. I never warmed to the blessed things though. For one thing they were more complex and tricky to start needing a big 2v accumulator. I know Iím repeating myself, but I lose count of how many novices I saw at the pondside struggling with a silly little 1.5v dry battery, which were always a complete waste of time, not to say a very expensive one. The accumulator had to be on fully charged top form for a quick start to occur, owing to the huge current drawn by the plug and for another, many glowplugs seemed to suffer from blowby leakage and finally, the poorer clothes-spin style glowclips were prone to fall off and even apart.

Anyone who has ever tried to start a glow boat single handed, will know that it is all but impossible. You had the boat gripped between your lower legs as you pulled the cord over and over and then just as the thing did start up, off would pop the glowclip due to vibration and she promptly stopped! In reality, you needed a pal to hold the boat down anyway and it was essential that once started he transferred one paw from boat to glowclip until the engine had warmed up sufficiently and you were ready to launch. Even then, removal of current from the plug would often cause it to stop, and of course the fuel itself was nasty old stuff to mix and use. Even back then we all knew that methanol could be absorbed through the skin and with nitromethane added to the hotter brews, both were really bad news for oneís liver, but then you could say the same of some nitrated diesel mixes. Talking of which, even with all the extra gear serious glow fans routinely carried by 1970 or so, they often resorted to a shot of diesel fuel squirted into the upper cylinder for easier winter starting. In case you doubt me, just try this modellerís easy start trick for yourself, because it really works. So, frankly my recollection of operating glow engines in boats is enough to give me a methanol headache, even sitting at a desk, they were that much of a pain. Even on the diesel scene back then, we had one quite famous club member using especially potent fuels, the exact recipe of which was almost a state secret! When he ran up his modified ETA 15 (with the Oliver Tiger, possibly the joint best 2.5cc British diesel ever offered for sale untuned) powered airscrew hydro in the great old pole racing days at Southchurch Park, he was surrounded by a strange smelling, swirling coloured mist - allegedly from nitro-benzene and other dodgy nitrates. Even as a stupid, mad keen, devil may care youngster, I knew this could only be bad news from a health wise point of view.

I often wonder if dear old ĎGadgetí is still modelling out there somewhere. The words health and safety had yet to be joined together by jobsworth/officialdom back in those Ďjust do ití days, when you could buy even the most dodgy chemical cocktail over the counter of any chemist shop. So yes, some things just had to change and rightly so, though other health and safety changes are harder to justify or understand.

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Pic 10: A boat for a glow? How about Harmonie III in a picture sent by keen reader John Tarvin of Burnaby MBC in Vancouver.

Though he still prefers his diesels

For example, I have a modelling friend in West Canada who tells me that one cannot buy model diesel fuel over there anymore, as the ether that a compression ignition engine depends on for starting, is now a banned substance. I was amazed and think this is a very nanny state. A way over the top over reaction, but itís what they have to put up with over there. As a result, a harmless easy to operate and cool running engine type is history for them - just mad. No doubt the same safety folk are quite happy with hot running glow engines, using nitromethane and methanol which are much nastier substances. Itís a mad, mad world readers, with just a trace, one suspects, of the not invented here syndrome being thrown in for good measure. Of course, I accept that i.c. fuel is not safe for human consumption. Just try drinking petrol, meths and paraffin, or inhaling propane or butane gas if you doubt wise old uncle Dave! On second thoughts donít try drinking or inhaling, otherwise we are all in trouble! All you need is common sense.

In many ways, the world or some of the more stupid people in it, would appear to have gone barking mad. For instance, I hear you mustn't use nicad batteries now, as cadmium is considered nasty, although old fashioned lead-acid technology and its delightful and perfectly safe fizzing sulphuric acid is still quite ok, I note with some amazement. I could go on, but will desist. Jobsworths as a word, might well describe this nanny industry quite perfectly. So guys, maybe Iím not the worldís greatest glowplug fan which is why this little feature is not illustrated with too many photographs. But, if I could have just a couple of mint and/or boxed classic glowplug engines in my collection, because I have none, they would be two fine British engines that I coveted as a young man, knowing I would never ever be able to afford either of them. They being, an ETA 29 5cc (see feature ad. from Aeromodeller - November 1959), and a Frog 500 Red Glow. The latter even better to own in its spark ignition form. If just one? Then it would have to be the ETA plus a big brass bedknob KLG plug to go in it! Iím especially taken with the ETA, as although around as early as the fifties, it was still powering 5cc hydros and r/c speed craft well into the sixties and I always thought it a most satisfactory piece of proper mechanical engineering , as indeed were their diesels. From the mass of similar and near identical German, Italian and Japanese imports there is pretty much nothing Iíd want, though I admit that the first O.S. 60 four stroke was a significant engine, but not in a high power way and anything from Rossi was always something special. A sort of model Ferrari!

From the many fine products of the USA, a K&B could be the nicest to own. Their Torpedo 40 was certainly the engine of choice of the scale Goodyear era before the FAI took a hand and ruined the pylon racers near scale looks. For that reason alone, any glow collector ought to own one. K&B had a hot line in racing marine outboards as well of course and not many sane engine collectors would turn down one of those. McCoy and Fox engines were pretty nice too and sold well stateside. Both deserved better here I always thought.

I donít think you can discuss glowplug engines from the USA without mentioning Ray Arden who invented the concept and 1970ís U.S. manufacturer Cox, who just must surely have designed, made and sold more glowmotors than anybody else in the world (maybe even the rest of the world put together ), though all at the smallest possible end of the spectrum and often in toys. Itís easy to dismiss Cox engines on those grounds and lots do, but do look closely at a Pee-Wee, Tee-Dee or any of them. They are little jewels really, even if their glowheads (as opposed to normal glowplugs), were an expensive pain beloved only of shopkeepers. Cox had simply hordes of imitators, but none ever approached Cox for sheer quality of finish and sales appeal. Iíve always thought that a collection of COX engines would look really lovely and take little space. An idea to consider?

And a nice boat for your engine

Iím closing up this month with a really nice old boat suitable for a vintage glowplug engine, Harmonie III built by reader John Tarvin out in British Columbia. Harmonie III was built from plans and is a typically top quality example of the sort of cabin cruisery much favoured by Dave. ĎI just received August 2006 MBí said John, going on ĎI had a shock when I saw Gwen Eagle in your column. I thought it was mine until I read the text. I built both this and Harmonie III from Model Shipwright plans.í Just the job for a Frog 500 petrol or red glow Iíd think, or even a marine Merco 29/35 if kept throttled back a bit. What do you think John? I think an ETA would be a tad too much BHP!

Over the next two months this long series finally closes, with a last Christmas Special in our January issue which is on sale in December. Join me then, just twice more, here at Model Boats. You wonít get another chance, though I might be appearing in these pages with a short run of mini vintage editions along Collectors Corner lines. My thanks again must go to ME columnist Malcolm Stride for pictures of his Merco 61. This is not the condition that I recommend you keep your engine in, but it is very typical of what collectors can be offered, or just stumble across. Fully overhauled, it is of course just as capable of powering a fast multiboat as it would have been back in the 1970ís or 80ís. Thanks again Malcolm - how about giving this game old lady a bit of a polish? (I can confirm that a mini series is in hand and will be published starting late Spring 2008 Ė Editor.)