I wanted more flight time than the 2 minutes allowed by the stock Cox tank. A custom 1/2oz tank will be mounted in the fuse which should easily allow 5 minute runs of the TD .020. That's more like it! Another benefit of that setup is that it allows use of the backplate to mount the engine to the firewall. This cleans up the front end by moving the engine back to where it should be with the prop just in front if the cowl cheeks.