I got this
radial.axis = -v.vector(5*cos(phi)*s**2, 5*sin(phi)*s**2) # -m*r*omega^2
transverse.axis = v.vector(5*sin(phi)*alpha, -5*cos(phi)*alpha)/(2.1*g) # m*R*alpha
I'm not sure this is correct though, what's happened to m*g being subtracted?
Is that needed?
I know where i was going wrong with the angles now, I forgot that they're measured from the line x=0 to the pendulum bob's position :P