Dynam Sukhoi

[RobinA]

Hi,bought me a new Sukhoi 26m and wish to do some 3D.What's the best prop?Very much want to hover this thing..............

Robin

[fhhuber]

Without knowing that specific airplane/motor/esc/battery package...

3D is all about thrust, not airspeed. So you want to go large diameter and low pitch.

Assuming its in the appx 1.2 to 1.4 meter wingspan range, reduce pitch 1 inch and increase diameter 1 inch from whatever came on it to improve 3D. (prop hanging, torque rolls, harriers...) This will also give better airspeed control on vertical down lines. (more prop drag with low or 0 throttle)

3D is also improved by pushing the CG back as far as possible (for your flying skill level). The further below the prop the weight is the easier it is to hang on the prop.
You can take this too far very easily... so move the CG back slowly. Start where the instructions say and push the battery back about 1/4 inch at a time until you need no trim difference upright vs inverted to hold level at about 50% throttle.
The tail will drop as airspeed goes down when you have it right for best 3D performance...
This means you have to train yourself to apply a touch of down elevator on landing approach or the model will stall and spin. (never good for this to happen while trying to land)
Stall-spin recovery will not be just let go of the sticks with the CG this far back. You'll have to find the correct throttle setting, apply elevator to get the nose down and use opposed rudder to stop the spin.

You'll have the plane on the edge of being unstable.

[RobinA]

Great,it's the Dynam SU 26.It has a 13-6 prop now.It's a monster.......................

Robin