Saunders Roe SR A1
Fighter flying boat designed in the early 50s. This example is housed in the Solent Sky Museum, Southampton.
A friend of mine was having a sort out and came across a part kit of this aeroplane by Wilmot Mansour. Designed by AA Judge for two Jetex 50s. He was kind enough to send it to me as I thought it was different and interesting.
Two Jetex 50s? You are having a laugh with this! I had enough trouble with one Jetex. So I dug deep into my "Man fund" and purchased two K&P 18mm ducted fans, 2x6amp ESCs, a K&P flight profiler and a 300mahr Lipo battery.
Most expensive 20" span kit ever!
The build is reasonably straight forward but I made a couple of changes. The wings are knock off using 1/32nd ply "biscuits" These are not fixed in place and can be removed and replaced quickly if damaged.
The floats are made from 3 layers of tissue paper glued over a blue foam mold, removed when dry and sanded smooth and doped.
The plan has an auto rudder to compensate for any asymmetric thrust from the 2 Jetex motors but this was not fitted.
The ducted fans are mounted in balsa tubes at the rear of the inner wing trailing edge.
The "electrics" are on the floor of the fuselage with the battery in the nose. This restricts the airflow somewhat so cheat holes were cut in front of the fans under the wing roots.
On the underside, the boat part was covered with thin paper to make it more durable against grass stubble etc.
The model was covered with medium Jap tissue. Watershrunk and then brushed with a thin coat of dope and then 3 coats of banana oil.
A thin spray of Spectrum silver. Just enough, so the covering is not see through.
The markings are made with inkjet waterslide transfer paper. From the internet, I copied a transfer sheet from a plastic kit and resized it to match the size of the model. The model was sprayed with clear gloss acrylic lacquer to seal the transfers and produce a reasonable surface texture.
The model is a tad heavy with all the electrics but the noise it makes is the most extraordinary sound that I have ever heard from a model. If you run it indoors it hurts your ears. Fantastic!!!
The model flies well with the battery well forward and just a tweek of rudder offset.