It has been a busy week. On Wednesday 8 Oct, I flew to Wichia for some avionics testing on the Hawker Beechcraft T-6B prototype. I flew three flights, finishing on Saturday, and came back home on Sunday. The T-6B has the same airframe and engine as the T-6A, but the avionics are all new, including a full glass cockpit, HUD, IRS, etc. Very nice aircraft.
Back home in Ottawa, I flew flight 7 on the RV-8 on Monday, concentrating on cruise performance testing. Flight 8 was on Tuesday, concentrating on airspeed system calibrations from 110 KIAS to 180 KIAS. The raw data shows about a one kt error at all speeds. The recorded data seems to confirm that. This afternoon I flew flight 9, doing a whole bunch of circuits with about a 5 kt left crosswind, sideslip tests, stalls, cruise power experimentation and a WAAS approach.
Flight 9 summary
Purpose: 1. Circuits, 1. SHSS build up.
1. Stall characteristics, 1. Min trim speed investigation1. Cruise power experimentation1. WAAS approach test
Snags:Turn coordinator needle does not move when the aircraft is yawed. The flag does remove when power is applied to the unit, so it seems that the gyro has died. Or, is it possible that there is some kind of shipping lock that I forgot to remove - I'll stick my head behind the panel to see if there is anything moveable on the other end of the instrument.
Results:No data was recorded, as the planned tests did not need it.
Circuits - 8 touch and go and one full stop landing were completed with approximately a 5 kt left crosswind. A final approach speed of 70 KIAS on the analog ASI was used, with full flap on all landings, except the final landing. The final landing was completed with 1/3 flap and a 75 KIAS approach speed. No handling issues were noted.
Stalls - with flaps up, at idle power, it seems that the aircraft cannot be completely stalled at full aft stick. Buffeting starts at 65 KIAS (EFIS) with full aft stick at 62 kt. There is no nose drop or wing drop, with aileron control still available. With full flap, there is buffet coincident with the stall at 51 KIAS (EFIS) The stall is identified by a nose drop, followed by wing rocking if the stick is held full aft. The ailerons remain effective.
SHSS build-up - idle power, full rudder steady heading sideslips were conducted at 80 and 70 KIAS with flaps up and with full flap. With flaps up, there is strong buffeting of the tail surfaces at approximately 90% rudder travel. The characteristic is the same in left and right sideslips. There is no buffeting out to full rudder with full flap. In principle, full rudder sideslips are only normally used if an approach is too high, so that would imply that full flap had already been selected.
Min trim speed - with full flap, and idle power, a small amount of aft stick force is required even at VFE.
Cruise power experimentation - the fuel flow system is still not completely calibrated, so no formal tests were conducted. It was noted that at 9500 ft, 2500 rpm and full throttle (21.2 in HG MP) and mixture leaned to 50 deg F LOP gave about 170 kt TAS (based on the EFIS IAS), and an indicated fuel flow of approximately 8 USG/hr.
A GPS Rwy 24 approach was conducted. The GNS 430 gave the expected indications, and the vertical guidance was present on the CDI. No anomalies were noted.
Total air time is now 12.7 hours, more than half way through the required 25 hours testing. I'm looking for some decent ballast to start moving the CG aft.
