The Australian Roulettes fly the PT-6 as well as a few other countries
I can't think of at the moment. Brazil perhaps? But one has to
remember, what aerobatic teams do, and what happens in an aerobatic
competition aren't identical.

The competition box is one size for all competitions, 1000 square
meters. Changing it would require sancitioning from the FAI. But
creating different sized boxes for different aircraft neutralizes the
spirit behind the competition.

Airshows on the other hand, boxes are determined mainly by the venue.

One of the reasons you don't see many more turbine GA aircraft is
partly due to the lack of certified small turbines. There is a
growing number of turbine homebuilts. Comp Air and Lancair being two
that offer kits designed for them. I've also seen an article on a
turbine RV-4 in Sport Aviation not too long ago. As time goes on,
cheaper and smaller turbines will probably have a greater presence in
the GA market. Don't know what the economics are though, how much
does a hot section cost compared to overhauling a piston engine? And
what does that translate to per hour costs?

No need to get hostile over all this, Holm. Turbines are not the
end-all, be-all of aviation. Jets, turboprops and pistons all have
thier strengths and weaknesses. And their appropriate application.
Aviation pistons right now are just at the top of thier game when it
comes to hardcore aerobatic aircraft. And you wouldn't put a piston
in a commuter airliner.

-j-