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Airscrew Renaissance

The arrival of carbon fibre B1 boats from Bulgaria through Norman Lara, has encouraged even more interest in the airscrew classes that has already been growing over the last few seasons. What is not generally realised is that airscrew boats were not recognised by the MPBA until 1968, making this the 50th anniversary of the F Class becoming an official class in Britain. These 2.5cc airscrew driven boats had been part of NAVIGA for many years but because of a blanket ban by the London County Council and consequent lack of recognition from the MPBA had not been allowed to run legally in this country. That is not to say that there had not been numerous examples running since early in the last century. Where these ‘hydro-gliders’ differed is that they were usually fitted with quite large motors, up to 30cc in some cases or even pulse jets, mounted on equally large hulls and run free. One example had a McCoy 60 on top, so one can appreciate the reluctance of any council or the MPBA to allow these. There were numerous commercial kits and published designs for smaller airscrew driven boats, many of which still turn up on ebay. Vic Smeed in particular tried to popularise these, lobbying the MPBA to accept them.

Hydro Glider Czech B1 line up Jiri Baitler design

On the continent, primarily in Czechoslovakia, Hungary and Bulgaria, they had developed in an entirely different way, having tiny sponsons and even vestigial wings to keep the equally minimal structure out of the water. Allied to the extremely powerful 2.5cc speed motors that were available, the world record was held by Georgi Mirov at 95mph. Werner Papsdorf of East Germany won the first B1 European Championship in 1963 at 105kph, the last time the B1s were slower than the A series boats.

By 1967 and the European Championships in Amiens, where Mike Drinkwater competed for the first time, the hulls were recognisable as what are still in use today, although there were several variations on the theme.

There were twin booms with a single plane, twin booms with steps and a flying tail as outlined by Mike Drinkwater in his article he produced for OTW, and twin front sponsons with a flying tail. The configuration that was to become the norm was the single boom with a riding plane at the bow and a flying tail with two small sponsons at the rear. These were in common use by Horvath from Hungary amongst others, but it was Jiri Baitler’s ‘proa’ style boat with a single tube hull and one outrigger that proved hard to beat. In Amiens, Baitler from Czechoslovakia won the class at 182kph with Mike Drinkwater 6th at 140kph.

Left: 'Matchstick' in foreground

After lobbying following the return of competitors from Amiens, the MPBA relented in 1967 and established the F Class for 1968. Mike Drinkwater demonstrated the class at regattas, using no less than five boats on one occasion, including ‘Matchstick’, his take on the Baitler design. Mike set the British F class record with this boat at 108mph (173Kmh) whilst Baitler won the Europeans at Russe in 69, the first time 200kph had been exceeded in the competition.            Right: A selection of Mike's boats including a fearsome pulse jet

Once the class was established the number of competitors in Britain soon grew with Mike, speed flyer Ray Gibbs who used the Carter Special from his speed model, Pauline Husbands, and Pete Hough competing abroad regularly. Jean Peidnoir who also won the European Championship in 1973 wrote articles for Model Boats in 1974 describing alternative designs, which engendered even more interest in this country. Trevor Biggs, Jim Free and Ian Mander amongst others were all trying to match the best of the continentals.

Mike Drinkwater produced a number of kits aimed at beginners,  whilst Ian Mander started to supply a few top of the range boats, as the F2A technology he was so involved in played a large part in B1 design and construction. Several A series competitors also dabbled, especially in 1975 when the Championships came to Welwyn. A boat imported from Russia with a very rare Kostin motor became the fastest B1 in this country, although the record was never claimed.

Hungarian 'Baitler' boat with aluminuim wing rather than bridle Conventional boat with part wing of carbon

Speeds continued to rise until 1973 when nitro was banned in all NAVIGA classes, yet within a couple of years the ground had been made up and 250kph was in sight. There were inherent problems though, firstly ensuring that the craft was a boat, Ie. it would float when at rest, and secondly touch the water at times each lap. More problematic of all was meeting the noise limit set by NAVIGA, which caused untold disqualifications. Siggi Grasshoff won his European Championship in Amiens with an old Rossi powered boat simply because it was silenced and ran. On occasions entire runs have been completed with the boat feet off the water, but it is a contentious issue that has yet to be satisfactorily resolved and verifying whether a boat has touched the water at 280+kph is far from easy.

Silencer stifled performance Sprung loaded 'washer' Fixed front planing step

The single boom hull with a planning step at the front and a flying wing with two small sponsons or tappers is now standard although all sorts of alternatives have been tried, the oddest being a single front planning step set below the boat and even sprung in some cases.

'Tappers' 2.5cc Profi speed motor

With a Proffi, Kostin, Kalmakov or similar motor, B1s are capable of well over 280kph. We did see Pierre Barbotin and Anna Karavayeva both record identical record speeds of 285.261kph in France, while Jim Free holds the British record at a shade under 250kph.

1970s East German B1. Planes front and back. Rossi motor 2017 Bulgarian production boat

After far too many runs were voided in Championships, NAVIGA relaxed the noise limit on all classes putting restrictions on exhaust sizes instead, but this put British competitors at a distinct disadvantage as they still had to run with silencers in this country. The need to use silencers did see interest waning until a decision was made to adopt the same exhaust outlet rule. Rick Neal with one of the new Bulgarian boats has already exceeded the British record, but only in practice, and with several all carbon boats now in the country, a new record could be in the offing.

In Britain a second airscrew class was introduced B1R (restricted) with a view to keeping costs down by setting a relatively low price limit on the motors that could be used, still less than £100 with the most popular and fastest being the MDS, available from £25 upwards as against the £400-£600 for a Russian 2.5cc motor.

Restrictions were also placed on the propellers and materials that could be used in the construction of the boat. The materials rule was relaxed so that the same hull could be used in both class, now renamed B1S (sport). Even with the cheaper engine option, the B1S is no slouch, with Jim Free regularly recording runs over 120mph.         Right: MDS powered B1S

There is one last airscrew class in this country and that is for Vintage boats, designs and motors that predate 1963, which includes several of Mike Drinkwater’s early boats, many of which are still in existence.

For a more detailed account of Mike Drinkwater's involvement with airscrew driven hydroplanes for over sixty years see the excellent article he produced for OTW.

 Victoria Park regatta May 2018

The lake was heavily weeded so we set up a rope and pulled it clear of the circle. It was a enjoyable day with some good runs.

It was good to see Dave Sheldrake back in the water with his new B1S boat using a Nova Rossi engine and going well. Bryn Colman had his diesel A1 with a ED engine but no luck with it, so it was back to Weston UK to improve the power out of it. Stuart Falconer had good runs with his A2Sport although the A1 proved hard to launch so Pete Dirs showed him how to launch the model.

The lake after de-weeding Pete Dirs awaits the next 'customer' Pit scene at Victoria Park

John Underwood had good runs from both his boats A2 Sport and A1 so was very happy with the day. Rick Neal had a good run with his A1 but on the second launch he broke the wing of the model after a bad launch. Pete Dirs ran his ex David Winter A2 vintage boat and had good runs for the old and original ETA 29 engine

All in all it was a good day and thanks to Doug Ettridge for helping out with the time keeping and answering the questions put to him.

B1S Class Dave Sheldrake 92.23mph A1 Class Rick Neal 89.26mph  John Underwood 80.61mph Vintage Pete Dirs 55.70mph
Sport 40 Stuart Falconer 94.30mph  John Underwood 72.70mph

Thanks to Norman Lara for report, results and photos.