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Sunday 20 Sept 2009
0.6 air time
0.6 flt time

Purpose:

Handling tests at mid CG. 75 lb of ballast was well secured in the aft baggage compartment to bring the CG to 82.34" aft of the datum at engine start.

Events:

  1. Static longitudinal stability tests with one-third flap and zero flap at low speed.
  2. Static lateral and directional stability tests with one third flap at low speed.

Results:

  1. The flight was cut short due a buzzing sound that started after one of the early test points. After landing, it was noted that the left wing intersection fairing rubber seal had come loose in a small area near the leading edge.
  2. An interesting event occurred while doing a right wing down, full rudder, steady heading sideslip test with the fuel supplied by the right fuel tank. The sideslip was sustained for longer than previous tests, with 30 degrees of bank required to hold heading - then suddenly the engine stopped, apparently due to fuel starvation - it was very quiet for a few seconds. The engine restarted immediately when the fuel was changed to the other tank. The fuel was left on the left tank for the remainder of the flight so it could be seen how much fuel it took to refill the right tank after landing. Only 4.6 USG of fuel was required to fill that tank. It is hard to fathom how a fuel pickup could unport on a tank that was almost 80% full but I can't come up with any other possible cause of the momentary engine stoppage.

Lessons of the day:#. Do all tests at a safe altitude, to allow recovery from unexpected events.#. Select fuel to high wing prior to sustained sideslips.

New Snags:

  1. Left wing intersection fairing rubber strip has come loose three times. It was planned to use glue to secure the rubber seal to the intersection fairing after the aircraft had been painted. Perhaps it will be necessary to do this now.

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.