I have the two notebooks that were used by Dave Braun during the time frame that B-TR was revived in California by Ken Smith and the local guys. It includes the handwritten equipment rules, eligible planes, etc.
When there was a brief revival more recently (2005ish), it was thought that modern available engines would be needed if there was to be much interest. The old engines were grandfathered by allowing a .29 as long as it was single bypass, baffle-top--but then the displacement for a modern engine was set at .28. So you could run the old stuff but the guys running new stuff would have to lose in the pits for you to win. As it was, a modern .25 pumped out enough horsepower to make it a pretty spectacular event for pilots flying 3-up. Unless an exceptional amount of effort was taken to keep the plane light, it was still a "strong arm" event.
I suppose I have more "arrested B-TR construction projects" than anyone else has admitted. I have the very cool "Heinz 57" Dawson original, which is actually complete. It is a biplane hollow log and I think we flew it maybe a half dozen times. It got away from us on one launch and torque rolled into a balsa confetti storm. Fortunately, Dawson was able to piece it all back together. It was a handful when powered by an OS .25FX.
I have a Firecracker that has most of the woodwork done, and maybe all of the systems figured out. It is set up for the Webra .28. Considering the tight cowling on this, switching to something else would probably require a new fuselage.
Most recently, I was working to finish a Veco team racer. Before too many other projects got in the way. It was just going to be a sport flyer. It is set up for an old OS .25FSR, with all of the systems figured out, but final assembly not begun.
I think I have a couple of other kits too. Thankfully, they are still in the box and I don't have to admit that they are partially built, too....
Probably won't race any of them, but they are fun to run, beautiful to look at (at least if it's not one that I painted myself) and more interesting than yet another profile racing class.
For guys that think the rules are too complicated, it would seem that they should be looking somewhere else. Personally, I think that is what makes the event interesting:
--Beauty gets you pit choice, which can help a lot if windy or if the pilot skill levels are not uniformly high.
--The use of limited fuel supply practically defines this event, with no required pits.
--Unrestricted fuel composition lets you develop your system for the sprints vs. the feature race.
There are more racing strategies in B-TR than others. I think that makes it much more interesting. That said, you can simplify things by using standard fuel, fixed venturi size, run of the mill finish and not worry about pit location, etc. But complicated? No. Just that they are not profile planes, and yes, you have to have a shutoff that works. And even a pilot head. Oh, the horrors...!
The Divot McSlow
Ref. NCLRA B-TR Rules
5. "Any single bypass up to .29 cu. in., or any engine up to .28 cu. in."