The OS 70 will fit, but the valve cover will stick out quite a bit. Plus, it's about 111-mm long from the front of the drive washer to the rear of the carb. Add another 11-mm for the supplied nylon motor mounts and you have 122-mm from the firewall to the front of the drive washer. As a result, you will have a fairly large unsightly gap between the front of the cowl and the back of the drive washer.

I took mine up for its maiden flight today, and it flew pretty good. It required two right clicks on the ailerons and a fair amount of down elevator trim to fly level. It's still too early to tell if it's a better flyer than my VQ Zero.