Engine Thrustline:
With a DA-150 and 32 x10 carbon propeller the Pitts requires 0° degrees‚ or just a very little
UPthrust, maybe 0.5°. Right sidethrust was set at 2° and has proved to be very close to perfect
on the prototypes. Of course, final settings can be fine-tuned to your liking after the first few
flights, and will ultimately depend on your motor/propeller set up.
Control Throws:
Aileron and Rudder measurements are at the root/trailing edge position. Elevator measurements
are at the widest chord position.
Elevator
All controls should be set with a dual rate switch. On high rate the elevator should really be at
maximum, up to 50 degrees up and down (approx. 170mm/7”), but in this case with 50% expo-
nential. Low rate should be approx. 90mm/3.5" both sides. This is the perfect throw for nice and
crisp snaps. If you like you can add about 20% exponential to the low rate setting as well.
Rudder
Set the high rate to maximum throw (about 200mm/8”) both sides, and at low rate reduced to
about 150mm/6”. Check your linkages and closed-loop cables and make sure that there is NO
slop at all.
Ailerons
High rate aileron throw for both top and bottom wings is 60mm up and down. Use at least 30%
exponential for high rate. For low rate you should decrease the throw to the
top
to 45mm, and
the bottom to 50mm. Yes, this is a reversed differential due to the hinge line being in the top skin
instead of on the centre line. You will have to finalise this differential figure during flight. At high
rate, for 3D manoeuvres, this doesn’t effect the rolling too much, so you can maximize the throws
to whatever is mechanically possible, even more up than down if you wish.
In General
Your Pitts S12 has very large control surfaces, which makes it very sensitive and reactive. It is
always possible that these huge control surfaces can flutter at high speeds if the assembly, servo
installation and linkages are not made perfectly. So please do yourself a favour, and make sure
that you only use the best servos available, as we have recommended, and take the utmost care
making your linkages. Check every linkage regularly for slop, and rather reduce the maximum
throw than risking a high speed flutter due to sloppy servo gear or linkages.
We hope that you enjoyed the final assembly of your Pitts S12. Please let us know, if you think
that any hardware is missing or inadequate. We have tried to make this airplane as complete as
possible, and with good feedback from customers you will help us to continue making good
things even better. We appreciate your comments very much.
Email: [email protected]
Thank you!
Your Composite-ARF Team
Composite-ARF Pitts S12
15
Mike C (26 April 2005)
Mac