Design description

The complete design was made with the use of CAD/CAM system. The attention was focused at reliability, complexity, simplicity, low weight and affordability.
The governor itself is very compact, shorter then any competitive one. The unique design of relief valve enabled to minimize dimensions and considerably cut weight. Also other parts are optimised in order to keep robust design at minimum weight. The standard governor design is depicted at Fig. 1

Fig. 1

JIHOSTROJ GOVERNOR IS THE ONLY GOVERNOR THAT FITS SMOOTHLY TO NEW ENGINE ROTAX 912 iS

The housing, cover and base are made of aluminium. There are used high quality aluminium forgings. Finished parts are anodised. Drive gear shaft, gear plunger and flyweight are manufactured from hardened and heat treated steel alloys. Speed adjusting shaft and control lever are made from stainless steel.

The body contains the necessary passage to channel oil to the propeller pitch changing mechanism without a need of any plugs. The base is designed to fit the standard AND20010 engine pad – see Fig. 2.

Fig. 2

The governor is available with CW or CCW rotation and as pressure to decrease or pressure to increase type. This is achieved with base, housing and pilot valve plunger arrangement.

Above described design is the basic one which can be modified if necessary for some special installations:

1) Long control head – see Fig.3
This control head arrangement increases governor length what can be useful for instance for retrofit installations.

Fig. 3

2) Speed adjusting shaft with the opposite sense of rotation (available only for standard short cover) - see Fig. 4.
At certain installations can be problematic placement of control cable or push-pull rod with standard governor arrangement. This design reverse rotation of speed adjusting control lever.

Fig. 4

3) Pressure to decrease governor with accumulator connection fitting – see Fig. 5.
This governor was designed for installations where is necessary to use an accumulator - for instance aerobatic airplanes. Housing of this governor is made from machined high quality aluminium bar stock, the connection fitting is made from stainless steel.

Fig. 5

Fig. 6

The unfeathering capability is not incorporated into the governor but is assured with Unfeathering Solenoid Check Valve (USCV) which is operated electrically. This valve is connected between the governor and accumulator – see Fig. 7.

Fig. 7

The USCV is designed for either 14V (CV-04-14/E1) or 28V (CV-04-28/E1) operation. In principal it is a check valve which opens oil flow in accumulator and closes the flow from accumulator when deenergised. When energised the valve is open and oil from accumulator flows in the governor - see Fig. 8.

Unfeathering solenoid valve - function scheme

Fig. 8