Looking for info on rudder dimentions

[fdisk]

I'm looking for some information about rudders and how their size, shape and orientation effects flight.

I have one scratch built plane that, althought it turns almost too well, I still wonder if I have the rudder optimized.

I also have a bashed (in more ways than one) Koyosho Cessna that doesn't seem to have enough rudder for enjoyable flights. It might be scale, but if so is the flight handling then real flights must be a little weird.

My primary interests are height and length characteristics and what a diagonal trailing edge like the Cessna does.

[Sparky Paul]

The vertical fin size affects flight as you expect.. but you're somewhat unclear as to what you don't like about the way the plane is flying.
More details?

[fdisk]

I just realized the mechanical throws on the Cessna were way down so I upped them to max. Maybe that will be enough.

I'm still a greenhorn, so maybe this is even supposed to be the way things are. The problem I have is that it won't turn without up elevator. Left or right seems to do nothing, but pulling up with left or right gives instant gratification. Steering is acomplished by pointing the top of the plane in the direction of the turn and yanking the elevator. I imagine that is how alierons feel except I bet they roll the plane without having to pull up. I tried down elevator to see if it worked the same, but Koyosho left very little room for down so I can't really tell.

My parkfliers can roll +/- 45 degrees and sort of steer like a motorcycle. A little up ele might be needed to hold height, but the roll is induced by rudder alone.

I should point out that I am trying to bully a 42 oz Cessna plane with a 550 motor and 8x4 prop around in an area the size of a soccer field. Maybe they aren't supposed to do that, but it is all ready doing pretty well aside from zero roll ability.

[Sparky Paul]

For good performance, a rudder plane (no ailerons) needs a lot of dihedral.
The lower the dihedral the poorer the response is.
Try more dihedral.