Very informative memo from Pat Johnson.
Bob,
Here is one perspective about the Strega. In fact from the one who
actually drew the plans for both Windy and Brodak. That plane was
specifically designed for the ST60 and was no doubt adequate to say the
least with that engine. I have had the Saito 56 in planes that formerly
had the ST60 and could find little difference between the two. That was
even using a somewhat smaller venturi by far than is compared to the
stock R/C carb. I suspect that the .62 should be totally great in the
Strega. Possibly just about perfect. However, that being said, the 72
and OS70 both have the capacity of swinging 14" of prop and if a person
wants buckets of torque, they will work. I designed Shadow Cat for
David Gresens for his 72. He turns a 14-5 wood Zinger Pro series prop,
and it flew in some pretty nasty winds last Nats with no difficulty.
The weight is a little under 70 ounces. This and the Strega are very
close to the same size of plane, so there is a reference.
One little observation is that I felt that the four strokes performed a
little better at cooler temperatures and the difference between winter
and summer was definitely more intense between the four strokes and a
two cycle engine.
Feel free to post this memo if you like. If anyone wants plans to
Shadow Cat, I have them available.
Pat