1960s Stunt U-Control Fix-Up

[larry cottrill]

Two rugged and docile stunt U-controllers from the mid 1960s. I built the Super Ringmaster when I was 16 or 17; it is actually my second build of this model. I built the Junior Ringmaster a few years later, when I realized I needed something smaller and cheaper (and easily repaired) for practice flying. These will do about anything you want, though they are not as smooth in the maneuvers as ships that have a full stunt flap on the wing. The engines are McCoy Redhead stunt mills, engines so cheap they are almost regarded as junk engines. Good enough for a high school kid of limited means, though. The one on the Super is a .35 cu.in. engine; a .19 engine powers the Junior. Both these planes are plenty fast for stunt ships.

The Super has been kept out in the garage for years and is in terrible condition - the wing is covered with Japanese silk, completely filled with butyrate dope. It is as brittle as paper. There is a lot more damage hidden inside. The Junior was paper covered, and has been crashed and re-built (usually after a cursory inspection) too many times to remember.

Just so you young bucks will have some idea as to what it was like to do this stuff in the 1960s: The Super Ringmaster kit came in at $ 3.95 US and the engine was a whopping $ 4.95, brand new at the hobby shop. Of course, in those days a dollar was something. Ha.

L Cottrill

[larry cottrill]

Peeling off the top fabric of the Super Ringmaster outboard wing, I found:
- Mouse tunnels through several wing ribs
- An astonishing assortment of seed husks

However (and strangely, in my opinion) there was nothing I would describe as nesting material. I guess the critter thought the wing was a nice place to visit, but didn't want to live there. Kind of odd, I think, but we know from our pet experiences that rodents have odd habits.

I should have mentioned before that the wingspan of the Super Ringmaster is 42 inches (just a bit over one metre).

L Cottrill

[larry cottrill]

Here's how the repair of the Junior Ringmaster was handled. Wingspan of this model is just under 32 inches.

As mentioned, EVERY sheet balsa rib was cracked or split in some way. Some of the ribs were knocked completely loose from the hardwood spar. First the ribs were hit with a small amount of woodworker's glue, especially those that needed re-gluing to the spar. Then, each rib received two hand-cut strips (about 3/8-inch wide) cut from 1/16-inch hard sheet scrap balsa. These were fitted as two diagonals on one side of each rib, using plenty of glue. Making them diagonal creates a kind of "plywood' effect to strengthen the rib. You can see them clearly in the near wing structure in the first photo. These had to be carefully located to avoid interfering with the lead-out wires running through the inboard wing. They were much easier to fit on the outboard side since there I could just sort of "slap them in".

A couple of months later, I had settled on white iron-on fabric as the covering of choice, even though I had never used anything like it before. Once I figured out the right setting for the iron, I found it really quite easy to use. You first tack it down around the edges, then seal it down really well all around. Finally, you go over the whole surface with the iron, which shrinks the fabric tight enough to smooth it all out nicely. The hardest part is where you have to pull it down over the wing tips. The last photo shows minor wrinkling that I never could quite work out on the inboard wing tip (it's complicated by the fact that you have to notch it around the control lead-out wires). But, that's a very minor flaw - it will be hardly visible after a couple coats of aluminum dope go on. So, I thought this went really well for my maiden voyage in using it, and I'll certainly use the same material on the Super Ringmaster to replace that brittle well-aged silk.

L Cottrill

[larry cottrill]

I did manage to finish up the Junior Ringmaster this winter, and now I finally have a couple of photos. Haven't been able to fly yet, mostly because of windy weather. While this ship has plenty of power and speed (around 50 MPH in level flight), it is very light and does not hang out on the control lines very hard. So, in any kind of wind at all, you have to be always ready to step back to pick up slack in the control lines (45 ft of braided SS cable).

All the Ringmaster line were great flyers, though not as smooth in some maneuvers as the real "contest" stunt ships, which feature a full-width "stunt flap" along the rear edge of the wing (flap motion is less than and opposite to elevator travel). But the Ringmasters are a blast to fly, and will instantly do anything you can think of. They were also often used for "combat" contest flying by attaching trailing paper streamers.

- L Cottrill