From TargetWiki

Contents 1 How To Test Flight Models 1.1 Cruising Speeds: 1.2 Climb tests: 1.3 Turn Performance: 1.3.1 Chandelle or Combat Turn: 1.3.2 Instantaneous Turn: 1.3.3 Sustained Turn: 2 General Considerations 3 References

How To Test Flight Models

(From GHLieste)

Cruising Speeds:

• Set engine to give max continuous power (RPM and MP as POH).
• Either hand fly or use autolevel to create zero slip, zero climb rate, non-accelerating, non turning flight.
• Use trims to relieve control forces where available. Note whether trim has sufficient authority to eliminate stick forces.
• Make note of control deflection required in the absence of trim, and any residual control deflection required after full control application.
• Make note of IAS/TAS/Mach and Altitude of test, AOA and Weight of aircraft, plus any payload carried.
• Prop AOA, engine thrust, cooling adequacy at 0, 30% 100% if required - noting at what temperature the engine will stabilize.

• Repeat for a moderately fast cruise at an intermediate power setting, and for the minimum power required to sustain flight - noting what that power and IAS/TAS is, and fuel flow rates.
• Don't forget to use lean/rich as appropriate and to use proper blower stages for high power at high altitude - you should find better performance without at equal low powers however.
• Repeat for Full Power and WEP conditions.

Climb tests:

• Start below your target altitude, with aircraft configured appropriately for the climb, and at slightly higher than the desired climbing speed (IAS).
• While increasing power to your aircraft's listed climb power, gently initiate a climb, aiming to stabilize a climb rate at your chosen constant speed and at your target altitude.
• Repeat tests for a variety of speeds and weights.
• Test with cowl flaps open and closed, noting whether cooling is sufficient under climb power over a long climb at recommended and max rate/best climb speed.
• Repeat tests for climbs at reduced power and and full power.
• Repeat tests at takeoff power with full flap and gear and cowl flaps full open at low altitude.

Turn Performance:

Chandelle or Combat Turn:

From max level flight speed, perform a high-rate oblique climbing turn, aiming to smoothly alter direction by 180 degrees while converting excess energy to altitude. The turn should be completed wings level just above the stall facing 180 degrees from entry direction. Note handling problems encountered, and height gained.

Instantaneous Turn:

Note turn rate while holding the minimum of full back stick, buffet boundary, autorotative wing stall, and ensuring climb rate is near zero, and slip is near zero. Note rough times to complete each turn, 'g' and the rate at which speed is lost.

Sustained Turn:

For each weight and power combination desired, apply sufficient back stick to hold speed constant, while holding slip and climb rate at zero. Bleed speed by increasing turn rate, relaxing it for next test speed. Note power setting, weight, IAS, altitude, 'g' and turn rate for each test condition.

Note that some of this can be extracted by the FMtest applet, but there is a place for qualitative testing at the same time. Even with the automated testing, it can take hours to map the envelope of a single aircraft. And of course, all these steps must be repeated for left engine out and right engine out for twins to check single engine handling.

General Considerations

Remember though, none of that is worth anything if you can't fly accurately, or use the wrong parameters.

There is a huge amount of data required for the test to be worth anything as an input for FM evaluation, and all of it will require analysis for materiality and potentially re-testing whenever anything alters in the FM or test conditions. For confidence multiple tests under manual flight conditions should be taken for a couple of testing conditions that are representative. The variation, both magnitude and scatter of subsequent results will be of interest for tests of, e.g.,

• time to height - 'constant' speed climb at climb power between two specified heights ...
• max speed at a given power setting.
• sustained turn rate and time for a 'given' speed.

Interesting is the performance variation between two pilots on identical acm/scn. In testing I was consistently getting 3-4 degrees per sec faster times than my co-tester on one acm. (14 dps vs 10.5 or thereabouts). In this case a value of about 12 dps was appropriate for the maximum sustained turn rate, as the concentration level for the accuracy required to attain the higher rate was total.

References

• Amateur-Built Aircraft and Ultralight Flight Testing Handbook

Although beware some of the simplfied descriptions are incorrect on the FAA flight procedures, and following them without some interpretation would get you into trouble you could avoid. (from GHLieste)