For phase 1 flight testing we developed a spread sheet model that tabulates performance versus altitude. Inputs included LIV and test parameters. Model performance was made to reflect test performance by tweaking lift efficiency, propeller efficiency and parasite drag coefficient. The result was a model specific for our normally aspirated N304R.  Application to a turbo version would only require the addition of engine altitude performance.

Data collection was made easy through use of Cloud Ahoy. This free service provides runway and flight tracking data that includes wind, ground speed, TAS and ROC. The only flight data that’s needed to be recorded was pressure altitude, OAT and IAS.

This model was useful for converting test data to the standard data required for the POH. For example we were able to do better than commercial manuals by providing climb data for various weights and speeds. For example I was able to generate the following climb and cruise data versus weight.

N304R CLIMB AND CRUISE@ 2500 RPM, FULL THROTTLE WITH CLIMB @ 135 KIAS
WEIGHT LB	CEILING* FT	BHP %	GPH	CRUISE KTAS	NM/GAL
2500	17200	54.3	11.5	197	17.1
2900	15300	59.3	12.3	196	15.9
3300	13300	64.7	13.2	195	14.8

·         ISA Altitude for 300 ft/min ROC

Carl

carlscheid@att.net