This electrically powered 100” radio controlled model has been drawn and built from scratch. It has not used other model Hornet plans. Using original drawings and information kindly supplied by David Collins, Jim Butters and others, a drawer full of reference material was accumulated. The plans were then drawn for a model to 1:5.4 scale on three sheets larger than AO size. The 1:5.4 scale was arrived at to use 6” wheels (which cannot easily be made). It also allowed the wing to fit in the car in one piece.
It was designed to have electric power so that it could have loudspeakers in the radiator nacelles giving authentic Merlin engine sound recordings through the grills. I first developed this proportional sound in conjunction with a German Thomas Benedini on an electric powered HE111 in 2004, so the Hornet was an obvious choice of model. This sound product is now commercially available from Thomas Benedini at www.benedini.de
The design has the correct scale fuselage sections, wing incidences, wing areas, washout, wing sections, control throws etc as the full sized Hornet, and it is as accurate as I can make it. Compromises have had to be made with the internal retracting mechanism which is only a two link system, but this is not seen from outside. The legs, struts and wheel hubs etc are very close to scale. Jim Butters and David pointed out that even many plastic kits are incorrect on the wing sections inboard of the nacelles, and Jim kindly provided me a drawing showing the correct radiator sections and elevations.
The construction is predominantly balsa with fuselage ribs of 2mm Liteply and 3/32” balsa sheeting. The fuselage uses balsa ribs but the engine and undercarriage mounting uses 3mm Lite ply. The design took three months and the construction has taken a further 18 months, estimated at approximately 2000 hours.
The Motors are two Hacker Outrunner A60-24s driving contra-rotating 20” x 13” APCe props at 5000 rpm consuming 50 amps.
The batteries are two packs of 5amp hour Thunderpower Lithium Polymer Extreme batteries which give the model a flight time in excess of 12 minutes.
The retracting undercarriage units are mostly scratch built around two bespoke Unitract oleo legs. The legs are retracted by compressed air and the undercarriage doors are opened and closed by servos controlled by a timed sequencer. All three wheels retract and the tail wheel is also sprung. The normal controls are ailerons, rudder, elevator, throttle(s) and flaps, with an auxiliary channel for engine start / stop sound sequence and cannon gunfire sound. A further control channel is reserved for bomb(s) drop.
Vacuforming moulds from mahogany were made for the canopy, spinners and the wheel hubs. These were then delivered to a specialist company who produced the vacuformings.
The pilot has a radio controlled head and looks left and right in conjunction with the aileron control.
Test flights (twelve so far to May 07) have shown that the model has an excellent performance and it is easy to fly. The wide track undercarriage linked with the contra rotating propellers means that it tracks straight on take off and landing and does not nose over. In the air it has crisp responses to inputs and rolls and loops with ease. Flight times have averaged about 9 minutes to date to leave about 40% of battery capacity remaining. It seems to reproduce the reported responsiveness of the full sized Hornets. The following film was taken on the 6th May 2007. It was a very windy day, but the flying was successful.
http://www.youtube.com/watch?v=dAq_dgSyOEg
The sound of the Merlin engines as the model Hornet flies past gives the model that extra realism and also allows gunfire (sound ony!) to be generated from a switch on the transmitter. The full start and stop digitally recorded sequence of the Merlins is coordinated with prop turning to improve the realism effect. It is planned to fit the model Hornet with rockets and droppable wing mounted bombs.
Surface detailing + operational and maintenance markings follow detail shown on de Havilland drawing 3-2G7. Overall green/grey camoflage, with PRU Blue underside, is cellulose matt finish. Aircraft represented is WB909, 'N' from 80 Sqaudron RAF, while based in Hong Kong.
