/* Lewis formula for gear tooth strength
Copyright 2005 by Dale Heatherington (coded Oct 4 2005) */

function lewis(dataform,S,F,P,Y,RPM,T)
{

	var y = new Array(34);
	
	y[0] =  0.201;
        y[1] =  0.226;
        y[2] =  0.245;
        y[3] =  0.264;
        y[4] =  0.276;
        y[5] =  0.289;
        y[6] =  0.295;
        y[7] =  0.302;
        y[8] =  0.308;
        y[9] =  0.314;
        y[10] =  0.320;
        y[11] =  0.330;
        y[12] =  0.337;
        y[14] =  0.344;
        y[15] =  0.352;
        y[16] =  0.358;
        y[17] =  0.364;
        y[18] =  0.370;
	y[19] =	 0.377;
        y[20] =  0.383;
        y[21] =  0.389;
        y[22] =  0.399;
        y[23] =  0.408;
        y[24] =  0.415;
        y[25] =  0.421;
        y[26] =  0.425;
        y[27] =  0.429;
        y[28] =  0.433;
        y[29] =  0.436;
        y[30] =  0.442;
        y[31] =  0.458;
        y[32] =  0.463;
        y[33] =  0.471;
                
	S = S / 3 ;  
	
	var W = (S * F * Y)  / P ;
	if(T == "Rack") T = 300;
	var PD = T / P;
	var V = 0.262 * PD * RPM;
	W = W * (600 / (600 + V));
		
	dataform.W.value = W;


 }