function aknots=sound(TdegR)
% function aknots=sound(TdegR)
% Computes the speed of sound in knots
% Units are knots and deg Rankine.
% TdegR can be a vector or scalar. 
% aknots will be the same size at TdegR

R=1716.55;	%ft^2/(sec^2degR)
gamma=1.4;   % nondimensionsl
a=sqrt(gamma*R*TdegR);	%ft/sec
aknots=a*.5925; % knots
