Here's Airdale's site http://airdale.com/
There's contact info there. Try calling but email might be best as I know Steve goes to England a lot but keeps up with his mail. Hope all this is current. Last year I met a guy that was towing his Avid at a rest stop. Steve had just helped him finish assembly, covering, and mounting an E-81. It looked to me like some fine work and the guy told me Steve really knows his stuff. The engine was from Stratus. Good luck & please keep us posted.