I don't think so.

The 11x7 prop size WAS in the right range, when piped F3A engines of the 1970s and the beginning 1980s peaked on them, in the RPM range of 14,500-15,500. The prop sizes between 11x7 and 11x7.75 would put these .61 pattern engines in the 'meatiest' part of the power curve in flight, while performing their high-speed maneuvers (most pattern planes of that era would fall out of the sky at 50 mph... Not exactly 3-D types...).

Most muffler equipped .61 engines, the Thunder Tiger Pro included, now peak much lower in the RPM band, around 13,000 RPM, and without the tuned pipe; burdened instead by a 'noise regulations' restrictive muffler, produce significantly less torque around their peak.

As such, they typically need a significantly heavier prop to produce their best performance.
A vintage 11x7 would have the engine buzzing beyond its peak HP, for most of the flight, being on the rapidly descending, 'over-run' part of the power curve.

These engines will be close to their peak power in static condition, but with the smallish prop-disk of an 11" diameter prop, would not even make initial acceleration very dramatic...


The 12x6 size will load the engine down and is much closer to exploiting the meaty part of the power curve.
Perhaps a 12x7, or a 12.5x6 would be even better and this size range is the current benchmark for 'sport' .61 engines; not the bygone 11x7.


These 'factory engineers' are wrong, which may explain why TT is not winning too many events...