A very important performance index is flash temperature. Flash temperature is proportional to µ which is the lubricant viscosity; pm which is the mean pressure between the two surfaces, computed by means of the Hertz theory. pm is computed here according to this formula in which Er and R are the former parameters that have been used to compute the height of the lubricant film in the previous figure; w1 and w2 are two speeds which refer to the relative speed of the contact point with respect to the first surface, which is a cam surface, and the second surface, which is the rocker surface. If I get an observer which is linked to the cam, he sees the point of contact running with speed w1 on the cam, and if I take an observer linked to the rocker, he sees the contact point running with velocity w2 over the surface of the rocket; b is the cross length of the contact surface; a1 and a2 are two heat exchange parameters, which refer respectively to the first and the second surfaces.

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