Hi there:

I just want to know: why the pitch on pattern propellers are so high?

Happy Landings

Increasing propeller pitch increases the speed of the model. Classic pattern planes were designed to fly large maneuvers at high speeds.

David

Actually, Classic pattern planes normally used 11 x 7.5 running at 14k+ rpms 110-120 mph was the norm.

Modern pattern (2M) run 10 or 12 pitch because they are running much lower RPMs, the increased pitch tends to make for the same airspeed up, down and sideways.

Current pattern competition has sound limits placed on the models. So, it all comes down to noise, which comes down to limiting RPM to reduce the prop noise (which is the major factor on total sound levels). But pattern guys like smooth maneuvers, which require some speed (unlike 3D flying). To get the speed with low RPM requires fairly high pitched props.

Mark

Thanks, another question: what propeller do you recomend for pattern in a Saito 82?

The first increase in pitch away from the 11x7 Rev-up type props was to reduce noise. At the same time soft mounting started to come into play. My first soft mounts were on an Atlanta, home made from a design stolen from Dean Pappas. That with D&W 11x9 wides on a YS short stroke gave the same performance as the 14K+ Rev-ups with much less noise. Later higher pitched props were used on long strokes for both noise and speed reduction as turn-around came into place.

Stuart C.