There are not many infos on the web about this mechanic and i thought that the SSW were only a prototype for the SST Eagle (Super Stunt Trainer). But it is not. It is a Hirobo mechanic released (in the second half of '80), in collaboration with another japanease company, before the SST Eagle only for F3C conpetitions and available only on special order. So no stock in the shop. These infos has been confirmed from the guy who sold me the SSW in Japan. I asked also to Fabio Livi who has been an official Hirobo Pilot for many years (won several nats championship in my country and always in the fly-off during the World) ; he replied me that he flew SSW in the 1987 before the SST Eagle.
The kit is really a piece of art; the main transmission has two reductions; the first by belt the second with spur gears. It is similar to modern Kyosho/Quest Caliber 60/90.
It was available only in built version and with only the frame kit. So pilot could choose a competition head, tail and trasmission. Usually the Hirobo pilot used a DDF head others chose a Kalt or TSK head.
It was a very expensive kit; only the frame kit was 150.000yen (street price was 120.000y). In every case this frame kit was more expensive of full SST Eagle kit (see an attached pic of advertising of a shop in the japanease magazine "RC TECHnique" of 1988 with some prices). So you had to add also the price for a head (so about 35.000yen), a tail rotor (other 20.000yen), drive shaft and a body so final price could reach 250.000yen for the hely (without engine and elettronics). So in TSK helicopter's range.
With this mechanic you had to use an engine with normal head because the hely head was integrated in the aluminium fan (a true masterpiece) like you can see in the pics. My kit is complete with his manual and decals.