YS-11 Water/Methanol panel

Rolls Royce Dart engines have a Water/Methanol (or W/M) injection system to provide additional power during take-off and go-around procedure. The system sprays a mixture of water and methanol to the combustion chambers increasing the available engine power by about 400 shp (depending on local conditions). Procedure usually calls for a wet takeoff (with W/M) when the takeoff weight exceeds 48,000 lbs. or when operating out of runways less than 6000 ft long. It is possible to do dry takeoffs (without W/M) if the runway is long enough (around 9000 ft.) even at high takeoff weights, however, this isn't recommended. Time limit for the continuous operation is five (5) minutes. The consumption rate for the W/M is around 6.6 gallons per minute. The amount of W/M remaining is displayed at the fuel panel.

1. | Water/Methanol pressure lights, one per engine. These lights indicate that W/M pressure is great enough for the system to operate.
2. | W/M master switches, one for each engine. These switches control the shut-off valves that allow the W/M mixture to flow into the engine.
3. | W/M booster pump switch. This switch activates the three booster pumps in the W/M tank.

Both master switch and the booster pump switch must be turned on for the W/M injection to work properly. You can use the W/M injection for one engine only, but that's not recommended. When the system is ready to work, the associated pressure lights are lit.
The actual injection into the combustion chamber starts when the engine speed exceeds 14800 RPM. Likewise, when the engine speed drops below the 14800 RPM the injection automatically stops. Therefore, you can turn the W/M system on in advance without ill effects, but you must remember that the injection starts when the RPM exceeds the above-mentioned limit.