On the trip back from Geneseo with Clive in 2010 I was leafing through a book on post-war civil aircraft when I came upon a photograph of the Portsmouth Aerocar for the first time. I thought it would make an interesting rubber twin, but didn't hold out much hope of finding a 3-view for such an obscure aircraft (only one prototype was manufactured). Well, all credit to Portsmouth Aviation, who are still very much in business and have an interesting history section on their web site, including an excellent history of the Aerocar, with a 3-view and many photos. It took a while to get a plan drawn up, but I managed to get the model finished in time to take it the 2012 FAC Nats.
Wingspan is 28" and the model structure was based on my successful Argosy, though the fuselage was rather simpler, being slab-sided. 1/16" balsa was used for most of the model, including the fuselage box, as I wanted to keep the weight down as much as I could. The wing is cracked rib construction using two spars, with removable outer panels. The booms sit high on the wings, and the high thrust line means there there is just room for the rubber to pass over the wing spars on the way to the rear peg. It is just possible to swing a pair of 7 inch props - they just miss the cockpit. As on my other muti-engined models I used commercial plastic props (these are standard Peck items) both rotating the same way.
The model is covered in Esaki tissue - all white, apart from the fuselage in black, so that it would look dark when you look through the windows. The window material is from two large boxes of Tesco fresh cream doughnuts (!) I don't know what it is, but is thin, light, and has a good stiffness. Only the two upper corner windows are stretch moulded - all other panels are cut from flat sheet and attached with Formula 560 canopy glue. Paper patterns were cut first to get the shapes right.
The paint finish is Xtracolor RLM Silver enamel, thinned with dope thinners and all markings are cut from painted decal film. Final weight came out at 77 grams without rubber or noseweight.
First flights were made at Geneseo after the static judging, and after adding quite a bit of noseweight (I'm very glad I built a noseweight box into the bottom of the nose block) it flew pretty well. Ideal power seems to be one loop of 1/8" and one loop 3/32" rubber in each nacelle. It does tend to stall a bit when the power runs out, so I will be playing with the rudder trim tabs and sidethrust to see if I can get a circling glide, rather than a straight one. Flights so far have been between 30 and 40 seconds, but I'm sure there is more to come.