21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-1.1.1

PERFORMANCE FLIGHT TESTING OF AN F-111 C AIRCRAFT

Brian G., Woodyatt B., Bramley K., Snowden A., Morris C.*, Russel T.*
Aeronautical and Maritime Research Lab., Australia; *RAAF, Australia

Keywords: performance, flight testing, f-111 c aircraft

The Royal Australian Air Force (RAAF) expects to be the sole operator of F-III aircraft after 1998. To maintain reliable operation of the ageing F-III C fleet, the aircraft's Pratt and Whitney (P&W) TF30-P-103 engines are being replaced with higher performance P&W TF30-P-109RA engines. This will result in a unique variant of the F-III aircraft. A flight trial was conducted by the RAAF to characterise the change in performance of an F-IIIC aircraft installed with TF30-P-109RA engines. Traditional performance test techniques, dynamic manoeuvring and mathematical modelling were used to evaluate aircraft performance and airframe lift and drag characteristics. The take off and climb performance of the trial aircraft were found to closely match data for the F-IIIG variant. Descent performance of the trial aircraft did not match F-III G data, and this was attributed to the Mach Idle Bias controllers fitted to the TF30-P-109RA engines. Lift and drag characteristics were verified with manufacturers data, permitting cruise and combat performance to be estimated using mathematical models of the airframe aerodynamics and installed engine performance. The F-1I1C/TF30-P-109 aircraft has been approved for operational flying as a result of the trial.

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