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Flight Test Report on RV-8 N663DX
Test Pilot: David Allen
Builder: Ray Graham
First Flight
26 April 02 10 am local @ Sumter, SC. Conditions = CAVU 75F Winds light favoring Runway 05
Objectives: 1. Safe First Flight IAW FAA AC 90-89A
2. Check all installed systems.
3. Check all Radios except ILS
4. Run engine at 65% or greater for 1 hour.
Flight Narrative:
Took off tailwheel low. Lifted off at 55 mph IAS after approximately 400-ft run as predicted. Joined up with RV-4 chase plane for external inspection. No leaks noted. Checked airspeed and altitude against chase plane, AOK. Flew between 6500 and 10,500 ft checking systems. Max speed 190 mph IAS. Min speed 55 mph IAS (buffet onset). Return for landing, flew final at 85 mph IAS and perform a no flap, wheel landing. At 6500 ft, 24 squared: Oil temp 185, CHT 330, Oil Pressure 82psi, Fuel Pressure 3.5, Voltmeter 15. The following systems operated normally: VOR, Com radio, trim system, fuel system on both tanks, carb heat, mixture, prop control, throttle. Discrepancies noted in the following systems: GPS intermittent, mode C erroneous, flap linkage disconnected on second deployment to full at 90 mph IAS. Flaps retracted for remainder of flight.
Post flight actions:
1. Repair flap linkage.
2. Tighten Loose GPS ant. Connector.
3. Complete post flight inspection.
Flight #2
28 April 02, 10 am Local at Sumter SC. 78F winds 220 at 10-15.
Objectives:
1. Safe flight.
2. Check flap actuation minimum of 5 times.
3. Full stalls power on/off, flaps up/down/partial.
4. ILS check.
5. Airspeed Calibration.
6. Operate engine at least 65% power for 95% of flight.
7. Airspeed 220 mph indicated.
8. Pull +3 and 0 G's.
Flight narrative:
Took off in 2 point attitude, rotated at 65 mph indicated. Climbed to 6500 feet and stabilized at 24 sq.(Oil temp. 185, press. 82 psi, CHT 330, Fuel press. 3.5, Volts 15dc). GPS is now normal.  Slow to 100 mph indicated and raise and lower flaps 5 times. Completed stall series and noted the following results. Power off flaps up stall occurred at 55 mph indicated. Power off flaps down stall occurred at 52 mph. Power on flaps up = 52 mph IAS. Power on flaps down stall occurred at 48 mph IAS. All flaps up stalls were preceded by a 3-4 mph warning buffet and a quick break (usually left) which was controllable with rudder. All flaps down stalls were preceded by a 3-4 mph buffet followed by a sharp left wing drop, which couldn't be corrected with rudder. Recommend a rigging change for a more balanced flaps down stall. Accelerate to 220 IAS, no problems noted. Attempt to pull +3 G's and 0 G's and note that the G-meter is inop. Estimate G loadings. Perform timed runs to Calibrate airspeed indicator. Take vectors to ILS at Shaw AFB. ILS indicates normally in both Glideslope and Localiser. Return to Sumter and perform 3 pt landing.
Post-flight Actions:
1. Uncage G-meter.
2. Recommend rigging adjustment to avoid left wing drop full flap stalls.
Flight #3
28 April 02, 1 pm Local at Sumter SC. 86F winds 220 at 20-25mph.
Flight Objectives:
1. Flight at 230 mph IAS.
2. +5 to -1 G's.
3. Loop.
4. Rolls left and right.
5. Hammerhead stalls.
6. Spins left and right (1 turn).
7. Demonstrate Max Crosswind landing.
Flight narrative:
Practiced min take off roll. Tail low lifted off in approximately 300 ft. Climbed to 8500 ft and level off. Perform 230 mph tests. All controls perform normally with one exception. When the right rudder is deflected at any speed above 225 there is a high frequency metallic "hum" noise. G-meter performing normally. Loop, roll, spins left and right, and hammerheads left and right all as expected. The ailerons have a aerodynamic "ratchet" when deflected past 50%. This is common to all RV's. Estimated maximum roll rate is in excess of 120 degrees per second. This engine is particularly resistant to stalling from negative-g fuel starvation, even though it's not equipped with an inverted fuel system. Return to pattern for touch and go's. Perform 2 pt landing with 25 mph direct crosswind on runway 32 (grass) for maximum demonstrated crosswind component.
Post flight actions:
1. Rudder: Determined that the rudder hum when deflected right at speeds 225 mph indicated and above is most probably due to an area of skin on the left side of rudder that is "oil-canning". Recommend reducing redline to 220mph until repaired/replaced.
2. Adjust flap rigging to alleviate left wing drop during flaps down stall.
3. While performing the rigging adjustment, it was noticed that both aileron rod end bolts were slightly bent. Since we are unable to determine exactly when they were last straight we have replaced and will closely monitor for duration of flight test period.
Flight #4
2 May 2002 11am @ Sumter SC. 82 degrees/winds 230@15.
Flight Objectives:
1. Increase TO weight to 1700 lbs.
2. Move C.G. aft of center.
3. Check Stalls after rerigging flaps.
4. Check ILS.
5. Fly 2 hours.
6. Pull 3g's to check aileron bolts.
7. Check fuel consumption.
Flight Narrative:
Took off and climbed to a block of 6500 - 8500'. Remained within 5NM of Sumter. Performed full stall series. The stall characteristics are now much better. The plane still tends to drop the left wing with the flaps down, but it is now controllable with the rudder/aileron. All radios except mode C are working correctly. Pulled +3 g's and reached 220IAS.
Post Flight Recommendations:
1. Install armrests and leg supports/padding to ease fatigue on longer flights.
2. Install padding on edge of glareshield above panel for safety.
Flight #5
8 May 2002, Sumter SC. Temp 75, wind 230@5.
Objectives:
1. Max gross weight tests.
2. Min TO and Landing rolls.
3. Climb tests at 70, 90, and 120 IAS.
4. Speed runs at 75% power.
5. Stall and Spin series.
Flight narrative:
After coordination with ground crew to measure distances down side of runway performed minimum T.O. and landing runs. Max power while on brakes. Release brakes and hold tailwheel down. With no flaps lifted off in 530' with 30% flaps lifted on in 475'. Landed with full flaps in a 3 point attitude. Used 60mph IAS and max braking without tire slippage and stopped in 485' from threshold. Climbed to 12,000' at 70mph, 90mph and 120mph IAS. Terminated the 70mph test at 9000' due to high engine temps. Performed 75% power true airspeed tests at 3500'(168ktas), 6500'(166ktas), and 9500'(161ktas). I expect that the gear leg pants and wheel pants will increase these speeds approximately 10mph.
Post flight recommendations:
1. Install gear fairings for more precise flight test data.
Flight #6
8 May 2002 @ Sumter SC. Temp 85 light winds.
Flight Objectives:
1. Evaluate Aft CG limit flight characteristics.
2.  Stalls/spins.
3. Various Landing configurations.
Flight narrative:
T. O. normal, climb to 6500' @ 120mph IAS. Monitor all systems in green. A/C feels less stable in pitch. At speeds above 120mph IAS the plane is only slightly positively stable. It is almost neutral. As I slow down the plane becomes negatively stable in pitch. At any speed below 100 mph IAS when you pitch the nose up and let go of the stick it continues to pitch up at approximately 5 degrees per second until stall. Upon stalling, the nose pitched down normally. This was consistent at all flap settings. Performed stalls and 1 turn spins both left and right. Stalls and spins would both recover, but seemed to require a significant push on the stick rather than the usual "release" of back stick pressure. Spin entries were also unusual. The entry was "normal" up to approximately 1/2 a turn. From 1/2 to 3/4 of a turn the aircraft seemed to try to recover itself. Bank angle, pitch, and rotation all lessened dramatically. Then after approximately 2 seconds and just as dramatically the aircraft would "snap" into the spin again. The "second" entry was faster and steeper than the first. Recovery was initiated at this point and required a stick push. These characteristics were more pronounced to the left than the right. I cut short the stall spin testing at this point. Returned to Sumter and had a normal wheel landing.
Post Flight Recommendations:
After consulting with the owner and builder of this aircraft and calling Van's chief engineer, Ken Kruger, it was determined that the C.G. was actually farther aft than was calculated preflight. The actual C.G. was 2 inches aft of the aft limit. We calculated the C.G. preflight by using the Van's supplied numbers for the moment arm for the rear seat passenger. We used bags of cement mix strapped into the rear seat for the weight. When we got out the tape measure post flight, it appeared that the Van's supplied numbers for the rear seat passenger were much farther forward than our ballast. When I asked Ken Kruger at Van's aircraft how they determine the rear passenger moment arm I learned that they did it by having a passenger get into the back seat of a RV-8 which was on scales. They then calculated the passenger's actual C.G. moment. While this is correct for a person in the back seat seated on seat cushions and having their legs extending forward to the main wing spar, it is not correct for bags of ballast sitting on the rear seat. Our ballast has no legs and was not sitting on the cushions so it's moment arm was about 5 inches farther aft than the factory supplied rear seat passenger moment arm.
Flight 7 & 8
May 2002, 80 degs. 1300lbs CG Middle.
Flight Objectives:
1. Obtain fuel flow numbers for climb and cruise.
2. Fly to local airport for Mode C check.
3. Obtain accurate time to climb numbers from 70 - 100mph
4. Fly 2.5 hours.
5. Perform all previous acro.
Flight Narrative:
Took off from Sumter on with full fuel on left tank and performed a cruise climb at 25 squared to 3500ft using 1.2 gallons. Switched tanks to right and cruised at 25 squared for one hour at 3500ft using 10.3 gallons. Performed several stabilized climbs and determined L/D max to be 85mph. Landed at nearby airport and had Mode C transponder worked on. Took off and cruised climbed at 25 squared to 9500' using 2.5 gallons. Switched tanks and cruised at 2500 RPM and full throttle and leaned out for 1.5 hours using 11.8 gallons (8 gph). Performed numerous rolls and loops. Everything performed normally except for Mode C which was determined to need replaced. Post flight inspection revealed that both aileron bolts were bent again even though we hadn't stressed the airplane beyond 4 G's.
Post flight recommendations:
1. Replace mode C.
2. After consulting with Van's Aircraft again on the bent aileron bolts the following actions were taken, first, the aileron stops were installed. Second, larger diameter bushings were obtained locally and installed.
Flight #9
June 2002, Sumter SC 85 deg winds 230@15.
Flight objectives:
1. Test aileron bolt modification by performing all approved acro combinations.
2. Pull +5 G's and -1 G.
3. Perform 5 turn spins both left and right.
4. Fly until 25 hours are on hobbs.
Flight Narrative:
Took off normally and climbed to block altitude 6500' to 9500'. Performed Loop, Aileron Rolls left and right, 4 point rolls left and right, Snap Rolls left and right, Immelman, Split S, Cuban 8, Reverse Cuban, Cloverleaf, Vertical rolls, Hammerheads left and right, and level +5 G turn (sustained for 5 seconds). Spun aircraft 5 turns left and right. Returned for several patterns and full stop landing. Post flight inspection revealed no bending of aileron bolts.
No recommendations.
__________________________________________________  Flight Test numbers for N663DX
(Max gross weight at sea level with a proficient pilot)
Stall speeds: 55mph IAS Flaps up Power off
52 mph flaps up power on
VSO = 50 mph flaps down and power off
48 mph flaps down power on
VX = 70 mph IAS
VY = 85 mph IAS
Glide Speed = 90 mph IAS
VNE = 220 mph IAS
Normal Approach = 75-80 MPH
Short Field Approach = 60 MPH
Cruise climb = 120 MPH
Minimum T/O Distance = 475 ft.
Minimum Landing = 485 ft.
Max Demonstrated crosswind = 25 kts.
Maximum level flight speed = 180 KTAS
75% Cruise = 170 KTAS @ 3000' 10gph
165 KTAS @ 9000' 8gph
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