It’s actually a hard tank with flood-off. Maybe you can see it in this picture, though the floodoff switch which reduces the load on the timer is on the motor mount on the other side. At this point I had the screws and switch taped to the cylinder and I was just trying to see how it was going to balance.
I didn’t actually start using bladder tanks until a couple of years ago when I discovered the red caps, which work great and you can use them with an ordinary needle valve. Now I use those up to about .29 size engines with the Texas timers mousetrap shutoff, but I still use hard tanks and flood-offs on the bigger airplanes.
The Okie Bird is about 480 sq. in. and the wing structure was designed before schneurle engines, but it is covered with poly span so hopefully it will be stiff enough. I bought the Cox Conquest back in the 70s when it was new and it was on my 500 Witchhawk for years. That airplane is pretty beat up but I may revitalize it or build a new one with a Veco .19 for the special event next year.