Alasdair Sutherland's own design, the Sonas 40
Featured as a free plan in RCMW Aug 2002
The Sonas 40 plan #2935 is available from Traplet Pubs.
Alasdair Sutherland wrote this report for the March 2005 edition of Aviation Modeller International :Fridays always have lovely weather it seems, and so it proved this weekend. It was a bit disappointing to have cloud cover on the Saturday and a bit of a breeze, but the wind direction was acceptable (onshore) and there was just a light rain shower. In spite of dull, damp, windy weather, an entry of 33 pilots, most bringing several models, was an encouraging turnout. I had a good collection of models to try, but I left the lightweight and low powered electric models and the brand new untested Northstar, in the car and flew the good old faithful Irvine 40 powered Sonas all day.
Another Sonas 40 powered by a Saito 45 FS was flown by John Ross. He built it from my plan, but used built-up wings for lightness and even built-up floats, covered with transluscent Profilm to show off the structure. His model weighs 5lb 4oz including floats. My plan shows foam wing templates, but John fed the root and tip sections into the Profili program (downloadable from www.profili2.com) and produced a set of blended rib shapes. John also flew his Laser powered Jenny and a 35" span 'bitsa' model with a 30 year old Enya 09.
Tom Bennett had a Kingfisher, from the Dennis Tapsfield plan, powered by a ST 3000, but it struggled to take off in the rough conditions. Having a big model helps in these conditions, but it does not guarantee success. It is wise to have a well proven model with well designed floats and a good reserve of power, like my Sonas.
John Campbell progressed from a profusion of of Northstars to Canadian designer Laddie Mikulasko's latest offering, the Arrow. It is superficially like his Northstar, with a delta wing and pylon mounted engine, but has a different fuselage and no tailplane. He too, struggled to get it airborne from Loch Insh's troubled waters and resorted to a hand launch from Phil Davies. Even that proved far from easy but the model did get a flight.