I’ve decided to treat my restored MFA Sport 500 fixed pitch to the latest .40 cu. in. engine from the Sanye works. Not heard of Sanye? You will I’m sure have owned at least one of their products in your modelling career as this is the factory that turns out the SC, Magnum and ASP line of engines. In recent years they have come a long way, although having said that I’ve never had a problem with the past variants. The cure to a ‘bad’ engine is usually change to a better fuel; preferably one without castor oil. Why manufacturers continue to plug away at recommending castor I will never know…..
Compared to the SC .40 MK1 in my Sport 500 Collective, this modern SC certainly looks the part with a meaner squarer profile. It’s also considerably more powerful than the previous version but this comes at the expense of slight increase in size. This engine is bigger in width and the carburettor rake is set at a greater angle. All this equaled to some ‘proper’ modelling to get it to fit my heli.
First job was to grind away the inside edge of the engine mount using my trusty mini-drill until the engine fitted This engine has 4 mm bolt mounts. My first instinct was to drill the mount for 4mm but (thankfully) a quick look at my other collective-pitch Sport-500 revealed that 4mm nuts on the other side would either not clear the main frame or seriously reduce available movement for adjustments. Out with the mini-drill again and some copper tubing was quickly cut into some spacers, neatly converting the engine to accept 3 mm.
Next job was the fan blades. Trimming the edges to clear the carb was the easy bit. Ensuring they are all the exactly the same was harder. In the end I jury-rigged the fan onto a drill and sanded down the blades as per a rudimentary lathe; seemed to work rather well. I used the hydraulic locking method to tighten down the drive nut before moving onto the fan shroud. Thankfully this required hardly any trimming to fit. Job done 🙂