Couple of small details:

In the late 70s, the Control Line speed record was over 200mph. Not by much, but over it. It was held by a Jet and was something like 205 or 210mph. The fastest piston model was a D Speed class model and it's record speed was tenths over 200mph. BTW, D Speed at that time was only flown by Open members if I remember correctly.

It's real hard to identify a speed model by looks. They really did all look alike. They'd discovered early on that the event was all about the engine and the prop. And the deal was to get the fuel right for the pressure, temp the day your were flying. The flyer would mix it right there on the line. Seems that the amount of nitro versus alky effectively changed the timing.... when the "explosion" happened. And of course, the other deal was to get the needle right for that run.

I CD'd a portion of the UnitedStatesC.L.Championships that were in North Carolina in the 70s. We had some small problems sorting out where to put the speed circles and dealing with the "posts". If you've not seen speed flown, there is a steel post at the center of the circle. The flyer takes off with the control handle in one hand, and usually with the other hand on the post. His first priority is to get the airplane out of the dolly. Then to not crash while getting the handle into the yoke that's on the top of the post. The yoke would swivel while holding the handle. And lastly, to fly the airplane without falling down.... grin.

Around that time, FORMULA 40 (a beginner's event) was clocking over 150mph. The class A's were doing better than 170mph. An .049 is a 1/2A because it's half the displacement of an A class engine. The half-A's were doing better than 110.

I think Doolings were gas weren't they? If I remember correctly, the spark plugs didn't give much trouble, but most speed runs ate the glow plug, so that hatch on the pictured airplane would have been quite functional for a glowfuel engine.