Cleaning & gapping lower spark plugs

8/13/16, Tach: 91.6, Hobbs:102.2

Cleaned and gapped 4 bottom spark plugs since the engine has gotten harder to start. This difficulty to start (now when cold) seemed to occur right after re-setting the timing to 25 BTC on each mag. On the prior maintenance, i noticed the timing had drifted to 27 BTC on one mag, and 29 BTC on other mag. Resetting this to 25 & 25 did make an appreciable difference in lowering my CHTs (TODO: find dates & download before/after logs).

I borrowed Adrian’s gap measuring tool (TODO: buy), and all 4 plugs were worn (or were never originally set) to gaps larger than 0.022. The acceptable range is 0.016 to 0.021. Some folks have said plugs wear 0.001 to 0.002 in 100 hours. This would seem to indicate mine were not gapped to start with or they wore very fast.

Flight #22

6/2/16

Added 40 more pounds of water. This time to the baggage compartment. I’m walking the CG backwards a bit at a time from the 80.04 empty to the rear limit of 86.8. Takeoff for this flight was CG=84.3.

Basic Empty Weight LBS Arm Moment
Left Main

435

93.96

40872.6

Right Main

435

93.96

40872.6

Nose Wheel

296

39.11

11576.6

Empty

1166

93321.8

Empty CG

80.04

Max Limit LBS

1868.0

Max Limit Aero

1600.0

CG Limit Min

78.7

CG Limit Max

86.8

CG Limit Max Aero

84.5

Pilot Station

97.5

Passenger Station

97.5

Main Gear Station

94.0

Nose Gear Station

39.1

Fuel Station

80.0

W&B this flight @ takeoff:

Full Dummy 3
Empty Weight

1166

93321.8

Pilot

250

97.48

24370.0

Passenger

80 Water

97.48

7798.4

Fuel

252

80.00

20160.0

Baggage

40 Water

126.78

5071.2

Weight

1788

150721.4

CG

84.30

Left Main

736.5

Right Main

736.5

Nose Gear

315.0

Due to a visual on heavy rain to the west, decided to takeoff and stay in the pattern for 30 minutes. After 30 minutes of doing 8 takeoffs and landings in the pattern, it appeared the rain wasn’t moving in or getting any worse so I picked up the flight plan and departed to the west. Wind was from the east and keeping the rain to the west from approaching. Experienced rain in the RV for the first time deliberately during this flight since I could dart into and out of the showers (this was light rain falling from clouds high above). No apparent leaks. Flew along the edge of a line of rain with clear to the east (Fredericksburg) and rain showers to the west (Madison/Greene). Darting to the North allowed me to get out over Rappahannock to the west and circle Mom’s house for a bit.

Upped the G’s to 2.83 G’s max during a few maneuvers.

Times: 33.4/36.1 Before; 36.3/39.1 After

Flight Data

Flight Map

Rain pictures from the flight:

W&B @ Landing:

Landing Dummy 3
Empty Weight

1166

93321.8

Pilot

250

97.48

24370.0

Passenger

80

97.48

7798.4

Fuel

73.8

80.00

5904.0

Baggage

40

126.78

5071.2

Weight

1609.8

136465.4

CG

84.77

Left Main

670.1

Right Main

670.1

Nose Gear

269.7

Flight #21

6/1/16

Preflight, removed front air dams in front of the #1 and #2 cylinders. Still missing air inlet ramps. 80 lbs water in the passenger seat.

Starting Fuel: 40

Starting Time: Engine: 31.6, Total: 34.2

Flight Data

Flight Map

Increased G loading to ~2.7 G’s

Flew with 80 lbs in the passenger seat (2x 5 gallon jugs of water)

Ending Time: Engine: 33.4, Total: 36.1

Totalizer: 19.3 Used, 20.7 Remaining

Dip 11L/10R

Fill 18.9 Total

Flight #20

Preflight: Removed elevator bell crank inspection ports on both sides to inspect the elevator push/pull tube, jam nut, and bolt holding the elevator horns together. All was nominal. Added torque seal to the jam nut and elevator horn bolt so I can see if it ever moves. Reinstalled two inspection ports (7 #6 screws each).

Fuel starting was 20L/20R. Totalizer remaining: 40.

Oil was above 6.0.

Preflight: Engine: 29.9, Total: 32.4

I installed the passenger seatback which had been removed for many flights. I filled a 5 gallon gas jug with water (40 lbs), and strapped it to the passenger seat. Slowly beginning to increase the weight to explore the CG envelope. I did some stalls at 0, 1/3, 2/3, and Full flap settings near the beginning of the flight while the tanks were still relatively full. The stall behavior is slightly sharper, but still very benign. The AoA audio tone warning beeps are now active since I calibrated the AoA gauge last flight and it is a very nice feature.

I also spent a bunch of time leaning the engine and watching EGT readings…see the flight data link below and plot EGT, RPM, FF, and MAP.

Post flight: Engine: 31.6, Total: 34.2

Time: Engine: 1.7, Flight: 1.8

Fuel ending was: Gauge: 15L/13R. Dip 12L/10R. Fill: 7L/9.9R (16.9 total)

Fuel totalizer used: 16.9

Remaining: 23.1

Flight Data

Flight Map

The totalizer seems to agree well with the fuel truck. The gauges seem to read 2-3 gallons too high in the mid range.