Yes, the tunnel you drill or melt out needs to be large enough that the extension cord with the connector on the end can be easily pulled through. If the wing is thick enough, you can use 1/2 inch pipe to drill the hole. If you use the melting method, the hole will be larger in diameter than the pipe because the heat will melt away the foam a little larger than the pipe itself. When you connect the servo lead to the extension cord, tie a string around them to hold them together inside the wing.