[RICE RACING]

Found this quote from a pilot in regards to water methanol injection on planes he used to fly:

"Hi Gents,

May I make a contribution regarding the merits of water methanol injection in piston engines.

My back ground is in aviation, both as an engineer and pilot. Many years ago, I spent a lot of time on Lockheed Neptune aircraft. This aircraft was equipped with both piston and jet engines.

The piston engines were Curtis Wright R3350 Turbo Compound 18 cylinder radial engines. The number 3350 referred to their displacement in cubic inches. The rated horespower at take-off was 3700 at 2900 RPM.

Two types of take-off power could be used. The first was a 'dry' take-off, using no water methanol and 61.5" MAP (Manifold Absolute Pressure). The horsepower produced was 3400.

The second type was the 'wet' take-off, using water methanol, and 59" MAP. The horse power produced was 3700.

The reason for the 300 HP increase was due to the cooling effect of the water methanol on the combustion temperature within the cylinder. This allowed the air/fuel ratio to be leaned slightly from a rich 11:1, to a best power ratio of 12:1.

In ordinary circumstances, the best power ratio of 12:1 could not be used in a 'dry' take-off configuration, because the engine would have suffered from detonation. Thus, the primary benefit form the water methanol was the avoidance of high combustion temperatures at high MAP leading to detonation. The methanol also lowered the freezing point of the water, preventing icing within the water tank at the higher altitudes.

The fuel being used was AVGAS 115/145. If a meaningful increase in power (auto engines) is required using water injection, then it will come from an adjustment (auto-lean system) to the fuel mixture at high power, whilst the water is flowing into the cylinders. Some trial and error would be involved, I would imagine. In any case, an air fuel ratio leaner than 12:1 (with water injection) would not be adviseable).

Incidentally, as a member of a group which still flies two Neptunes and a Lockheed Super Constellation, both of which are equipped with R3350 engines, we have had to resort to slightly lower maximum power values. This is because AVGAS 115/145 is no longer availble, as we can only obtain AVGAS 100/130 or AVGAS 100. Nevertheless, the performance / power is still impressive.

Cheers,

Kim."