Sorry, I misspoke regarding the "cross brace". I meant the aluminum tube which slides through the wing spars. Now that I re-read the post I have no idea where the idea of a "cross brace" came from.

We've beefed up the spring by inserting a rubber band through the spring. It added a great deal of strength to the spring but I can still foresee the wing pivoting in flight. I'm going to increase the length of the metal "studs" which fit into the fuse sides.

The use of zip ties is a good idea.

Thanks for the reply.