U.S. NAVAL TEST PILOT SCHOOL FLIGHT TEST …

1 USNTPS-FTM-No. NAVAL TEST PILOT SCHOOLFLIGHT TEST MANUALROTARY WING PERFORMANCEA pproved for public release; distribution is AIR WARFARE CENTERPATUXENT RIVER, MARYLANDR evised 31 December NAVAL TEST PILOT SCHOOLFLIGHT TEST MANUALUSNTPS-FTM-No. 106 ROTARY WING PERFORMANCEThis FLIGHT Test Manual, published under the authority of the Commanding Officer, Test PILOT SCHOOL , is intended primarily as a text for the pilots , engineers and flightofficers attending the SCHOOL . Additionally, it is intended to serve as a reference documentfor those engaged in FLIGHT testing. Corrections and update recommendations to this manualare welcome and may be submitted to:Commanding NAVAL Test PILOT School22783 Cedar Point RoadPatuxent River.

2 MD 20670-530431 December 1996 ITABLE OF CONTENTSROTARY WING PERFORMANCECHAPTERPAGE1 INTRODUCTION12 PITOT /STATIC SYSTEM PERFORMANCE23 ENGINE ASSESSMENT34 ENGINE PERFORMANCE45 HOVER PERFORMANCE56 VERTICAL CLIMB PERFORMANCE67 LEVEL FLIGHT PERFORMANCE78 CLIMB AND DESCENT PERFORMANCE8 APPENDIXIGLOSSARYIIIREFERENCESIIIIIFIGUR ESIIIIVTABLESIVVEQUATIONSVVISTANDARD ATMOSPHEREVIVIILEVEL FLIGHT WORKING Manual Chapter FLIGHT Demonstration Practice Exercise FOR PERFORMANCE FLIGHT Mission Specification Handbook TO PERFORMANCE FLIGHT Safety/Risk Incremental Quantitative and PERFORMANCE DATA VERSUS TEST DAY WING ONEINTRODUCTION1 . 1 OBJECTIVEThe Rotary Wing Performance FLIGHT Test Manual (FTM) is intended to serveprimarily as a text for the pilots , engineers, and NAVAL FLIGHT Officers attending the Test PILOT SCHOOL (USNTPS).

3 Additionally, it is intended to be a referencedocument for those engaged in rotary wing performance FLIGHT testing at USNTPS, theNaval Air Warfare Center Aircraft Division (NAWCAD), and other military and civilianorganizations interested in helicopter performance FLIGHT testing. A manual with such broadaims may fall short of its intended mark for some future users, however, in thedevelopment of this manual, the primary purpose was a SCHOOL manual is not intended to be a substitute for textbooks on , it is intended to summarize the applicable theory, show therelationship of the FLIGHT test variables to the theory, describe the FLIGHT test techniques, andaid in the data management required for each FLIGHT test.

4 The Rotary Wing PerformanceFTM is not intended to replace the FLIGHT Test and Engineering Group Report WritingGuide as the guide to correct reporting, but does contain a discussion on the missionsuitability or effect on mission performance of the various performance parameters and adiscussion of specification compliance where manual contains examples of performance parameters discussed in narrativeand graphic format. The examples in this manual show trends, contain examples of currenthelicopters, and are in the format currently used in the USNTPS Helicopter PerformanceTesting, Data Reduction WING FTM, since it is a text for USNTPS, contains information relative tooperations at USNTPS and NAWCAD; however, it does not contain information relative tothe scope of a particular USNTPS syllabus exercise or to the reporting requirements for aparticular exercise.

5 Detailed information for each FLIGHT exercise will vary from time to timeas resources and personnel change and will be briefed separately to each individual . 2 ORGANIZATION1 . 2 . 1 Manual OrganizationThis manual is organized into individual chapters. While an attempt is made to treateach subject chapter completely and independently, that is not always possible due to thevery nature of the interdependence of performance parameters. For example, engineperformance data (power available) influence hover ,poweravailable data and level FLIGHT power required data influence climb performance. Whereapplicable, reference to a preceding chapter will be made to show the 1 is an overview of the 2 is concerned with pitot and static system performance.

6 The source ofsystem errors is discussed along with some methods of reducing those of measured course, trailing bomb, trailing cone, tower fly-by, paced, and spacepositioning are 3 covers the area of engine assessment. Discussion includes engine/rotorcontrols and displays; engine/rotor operating procedures; engine/rotor start, run-up, andshutdown characteristics; engine acceleration characteristics; engine trim response;engine/rotor stability; torque matching; engine limiting characteristics; and powercontribution in 4 covers the area of engine performance characteristics. This chapterincludes the relationship of corrected engine parameters: corrected engine shafthorsepower, corrected engine gas generator speed, corrected fuel flow, corrected powerturbine inlet temperature, and specific fuel consumption.

7 Inlet recovery is discussed alongwith specification 5 covers hover performance and establishes the relationship betweenengine performance (power available) and airframe performance (power required). Bothtethered hover and free- FLIGHT test methods are covered in this chapter. Test methods for thefree- FLIGHT hover performance include ground reference using the hover height measuringdevice (HHMD) and air reference 6 covers vertical climb. This chapter deals with both test day vertical climbperformance and generalized vertical climb relationship ofpoweravailable and hover power required are brought together in the vertical climb. Groundreferenced and air referenced methods are 7 discusses level FLIGHT performance.

8 This chapter deals with both test daydata and generalized level FLIGHT performance. Again, this chapter draws together engineperformance (power available) with airframe performance (power required) and developsimportant aircraft performance parameters (range, endurance, and maximum level flightspeed). The test method using the constant weight to pressure ratio (W/ ) and rotor speedto temperature ratio (NR/ ) is compared to the constant weight to density ratio (W/ ) 8 discusses climb and descent performance. This chapter covers test daydata as well as generalized climb and descent performance. The chapter brings togetherengine performance (power available) and airframe performance (power required in levelflight) to predict aircraft performance parameters (rate of climb or descent).

9 Test methodsof power correction factor (KP), weightcorrection factor (KW), generalized climbperformance, and test day performance are . 2 . 2 Chapter OrganizationEach chapter has the same internal organization where possible. Following thechapter introduction, the second section gives the purpose of the test. The third section isa review of the applicable next section discusses the test methods andtechniques along with the data requirements and safety precautions applicable to thosemethods. The fifth section discusses data reduction, both manual and computer aided aspresently performed in exercises at USNTPS. This section is not intended to replace theUSNTPS Helicopter Performance Testing, Data Reduction Programs, butrather toROTARY WING it.

10 The sixth section is the data analysis. The seventh section covers therelevant mission suitability aspects of the performance parameter. The eighth sectiondiscusses the relevant specification compliance issues. The ninth section is a glossary ofterms introduced in the chapter. Finally, the tenth section is a listing of . 3 PERFORMANCE SYLLABUS1 . 3 . 1 OverviewThe performance syllabus at USNTPS consists of academic instruction, flightbriefings, demonstration flights, practice flights, exercise flights, reports, and evaluationflights. The performance phase of instruction culminates in a group Technical Evaluation(TECHEVAL) and an individual performance evaluation FLIGHT . The culmination of trainingat USNTPS is a simulated Developmental Test IIA (DT IIA).