Saturday 25 Sept 2009
1.5 air time
1.6 flt time
1.1 hrs to go to finish the official flight test phase

Inter-flight activities:

  1. Reinstall rubber sealing strip at left wing root fairing. Added pieces of duct tape on the bottom in an attempt to hold it in place.
  2. Checked elevator trim tab position. It had been left in the position required for trim at VNE with aerobatic aft CG from the previous flight. The plan was to adjust the elevator trim tab travel so this angle was achieved at the nose down limit, thus potentially allowing increased travel in the nose up direction. But, it was found that the tab was only a fraction of a degree from the stop, so there was little to be gained by an adjustment.


  1. Stability and control tests at aerobatic aft CG.


  1. Static longitudinal stability tests at idle and high power, at low and high speeds, with flaps UP, 1/3 and DOWN.
  2. Static lateral and directional tests at idle and high power, at low speed, with flaps UP, 1/3 and DOWN.
  3. Stick force per g tests at VA and VH.
  4. Two landings with 8 to 10 kt crosswind.


  1. Stick free static longitudinal stability is positive at high speed, at idle and high power.
  2. Stick free static longitudinal stability is weakly positive at low speed at idle power.
  3. Stick free static longitudinal stability is negative at low speed at high power. If the aircraft is trimmed at Vy with flaps up, 1.2 Vs with 1/3 flap, or 1.3 Vs with full flap, and the speed is reduced, a push force is required to stabilize at any lower speed. If the stick is released, the aircraft will decelerate to the stall. While there is little risk of stalling with max power if flying in VMC conditions, pilots flying at aft CG in IMC conditions should be aware of this adverse characteristic.
  4. Strong buffet with full left rudder sideslip with full flap at 1.3 Vs. The horizontal stabilizer tips move up and down several inches. Fortunately, there is so much discing drag at idle this prop that there should be no need for full rudder sideslips.
  5. A strong nose down pitching moment is seen at full rudder with 1/3 flap at 1.2 Vs with max power, likely indicating that the downwind side of the horizontal stabilizer is affected by disturbed airflow from the vertical stabilizer or aft fuselage.
  6. Stick force per g is on the order of three pounds per g.
  7. Static directional stability is strongly positive under all conditions.
  8. Static lateral stability is positive under all conditions tested.

Existing Snags:

  1. Max rpm still decreases late in the flight.
  2. SD-8 Alternator - must run power wire to regulator.
  3. Small amount of right rudder pedal force needed in cruise. Need to add a wedge on the left side of the rudder trailing edge.
  4. Pitch trim speed of movement is slow during a touch and go. Need to try it with the pitch trim speed governor removed.