Avro-Curtiss Waterbird Replica (LAA 392-15352)

By Francis Donaldson

In the early hours of a calm Monday morning in June, a hearty cheer went up from a small group of enthusiasts gathered on a promontory on the western shore of Lake Windermere. The cause of the spontaneous outburst was a heady mix of relief and joy at the sight of the replica Avro-Curtiss Waterbird G-WBRD lifting off from the water for the first time and flying steadily for a few seconds before touching down again in a flurry of spray kicked up by the heel of its big flat-sided wooden float. The event, which represented the culmination of a decade-long dream by LAA member Ian Gee, mimicked the first flight of the original Waterbird, Britain’s first seaplane, which made its first and only flights, also from Windermere, in 1911.

Ian had commissioned the replica to be built by Wickenby-based LAA Inspector Gerry Cooper, making use of the clause in the regulations that allows full-size replicas of historic aircraft to be treated as amateur builts even if they are a commissioned build.

The Waterbird was built under the LAA process, and is as close as possible to the original design as can be deduced from the few surviving drawings and components – the rudder and the float. Originally configured with wheels to allow it to be test hopped more easily, the re-engineered replica was the subject of a detailed stress analysis by John Tempest. So after a few further tweaks had been embodied LAA Engineering was able to clear it to be flown, albeit within a very restricted envelope – rather akin to the Permits that the LAA grants for Shuttleworth’s Bleriot and Deperdussin of the same Edwardian era.

After demonstrating that the wheeled Waterbird could fly across Wickenby Airfield under reasonable control, piloted by Gerry, the temporary undercarriage was removed and the aircraft changed to the original Waterbird’s configuration as a single-float seaplane, with design help from Cranfield University. The first flotation test, carried out at the National Water Sports Centre at Nottingham in 2020, showed that with the original size of float the replica Waterbird was woefully lacking in reserve buoyancy, the front of the float dipping under the surface as soon as the aircraft started to move forward under its own power. In the year that followed, the replica moved by road to Liverpool and a new float was made which is about 25% wider and longer than the original. The replica Waterbird was tested on the new float on Windermere in the summer of 2021, now under the supervision of LAA Inspector Bill Brooks, although on this occasion, in the Experimental Category. The 2021 trials revealed that while the craft could now be motored around the lake fairly consistently at a fast taxi speed, attempts to take off were prevented by a violent porpoising motion which was triggered if it was allowed to accelerate further.

Not to be put off, for the 2022 trials, acting on the advice of a number of experts in naval architecture, the steps on the float were made shallower, and the float position was made adjustable, allowing the aircraft to be mounted at a greater angle of attack and for the float to be positioned fore and aft for optimum balance.

According to theory, these changes would allow the aircraft to skim smoothly over the water like a hydroplane, supported by its twin steps. These changes were carried out through the LAA mod process, the aircraft having returned to the fold as an LAA project. Faced with the job of bringing the aircraft from Liverpool and re-assembling it in the Lake District, LAA Inspector Bill Brooks supervised the assembly and testing of the aircraft at Windermere, stepping into the breach at short notice after Nigel Jones was put temporarily out of action by an accident the previous week – though not to be put off, Nigel nevertheless turned out to watch the historic event.

By this time expecting to have a long programme of adjustments ahead of them, the Waterbird’s support team were delighted that the 2022 trial showed the aircraft’s water-borne behaviour to have been transformed at the first attempt, and four successful flights of progressively greater length and height were made on this and the following day, flown by Pete Kynsey. Pete reported that the aircraft flew remarkably well, with plenty of power to spare and good controllability for a craft of this era.

The replica is powered by a Rotec 2800 radial engine, substituting for the original’s 50hp Gnome rotary. The airframe consists of a huge number of struts wires and turnbuckles, and uniquely features bamboo poles for the tail booms. The engine, and its Diatex covering are about its only concessions to modernity.

Ian’s long-term hope for his remarkable aircraft is that from time to time, and when weather conditions permit, it will be able to make further demonstration flights on Windermere as a visitor attraction, and as powerful reminder of Windermere’s aviation heritage.

Above … and airborne!

Below A jubilant team, after the successful first flight.