V-22 Osprey Climatic Testing

Kenneth P. Katz Flight Test Engineer, 1989-1992 Boeing Defense & Space Group

2013 SFTE 44th International/SETP Southwest Flight Test Symposium

October 2013

V-22 Osprey

• Tiltrotor configuration – VTOL and hover capability – High speed and long range in airplane mode

• Joint service • Multi-role • Early program chronology

– JVX program start – 1981 – Bell-Boeing FSD contract award – 1983 – First flight – 1989 – Climatic testing – 1992 – EMD program start – 1992

V-22 Osprey

Climatic Testing Objectives

• Provide input to the Engineering and Manufacturing Development (EMD) program

• Verify system performance

• Identify system deficiencies

• Develop operational and maintenance procedures in climatic extremes

• Evaluate reliability, maintainability and supportability in climatic extremes

Planned Test Conditions

• Hot temperatures through +125 degrees F

• Cold temperatures through -65 degrees F

• Rainfall at 5 inches per hour

• Wind (45 knots) at different azimuths

Test Facility

• McKinley Climatic Laboratory, Eglin AFB

• Insulated hangar

• Extensive heating and cooling capabilities

• Air mass flow capability

• Solar simulation

• Rain simulation

• Wind simulation

Aircraft Installation Requirements

• Resist thrust forces and moments at all nacelle angles

• Restrain aircraft

• Protect facility from rotorwash effects

• Remove exhaust gases from engines and APU

• Electrical power integration

• Communications integration

• Instrumentation and data integration

Aircraft Installation

Aircraft Installation

Wing Mount

Forward Fuselage Restraint

Nosewheel Table

APU Exhaust Duct

Laboratory Floor Plan

Instrumentation and Data Acquisition

• Airborne Data Acquisition System (ADAS)

• Operational Testing Data Acquisition System

• Fiber optic link for flight control system monitoring

• Transducers – Test instrumentation (242 measurements)

– Avionics 1553 databus (145 parameters)

• Umbilical and interface to McKinley Climatic Laboratory displays

Planning and Preparation

• Planning began nine months in advance of the start of testing – Critical scheduling constraint: firm start and end dates

for access to facility

– Close collaboration between all participating organizations

• Preparatory lay-up for V-22A BuNo 163914 – Update systems configuration

– Instrumentation installation

• Comprehensive on-site logistics

Climatic Test Participants

• Boeing Defense & Space Group

• Naval Air Warfare Center, Aircraft Division

• Air Force Development Test Center

• Supporting organizations

– Bell Helicopter Textron Incorporated

– General Motors Corporation, Allison Gas Turbine Division

– Naval Air Systems Command

Aircraft Test Modifications

• Pilot control of weight-on-wheels state

• ECS proof-of-concept modifications

• Extensions for main battery cables

Test Conduct

• February-May 1992

• Intensive effort to meet schedule constraints

• Types of tests

– Shakedown tests

– Simulated mission profiles

– Systems tests

– Blade fold/wing stow tests

Simulated Mission Profile

• Start up – APU start – Unfold proprotor blades – Engine starts – Secure APU – Raise ramp – Exercise NWS and brakes

• Vertical takeoff (70% torque with WOW off)

• Flight control checks • Retract landing gear • Conversion

– 20% torque – Raise flaps – Lower nacelles

• Exercise systems

• Inflight shut down and restart one engine

• Reconversion – Lower flaps – Raise nacelles – 70% torque

• Extend landing gear • Vertical landing (lower torque

with WOW on) • Shutdown

– APU start – Lower ramp – Engine shutdowns – Fold proprotor blades – Lower nacelles – Secure APU

Test Safety

• Formal hazard review

• Egress demonstration

• Shakedown with progressive build-up

• Real-time monitoring of critical parameters

• Fire Department briefings about the V-22

• Safety observers during runs

• Firetruck outside the hangar during all tests

• Fall protection for personnel on the aircraft

Test Operational Restrictions

• Proprotor wash effects

– 70% maximum rotor torque in VTOL mode

– 20% maximum rotor torque in airplane and conversion modes

• Stored quantity of chilled refrigerant

– Limited duration of test at cold temperatures

Other Considerations

• Limited visibility during operations at extremely cold temperatures

• Human performance at extremely cold temperatures

• Commercial support equipment and electronics reliability at extremely cold temperatures

• Temperature stabilization (multi-day soak at test temperature) required prior to test run

Test Operations

-75

-50

-25

0

25

50

75

100

125

2/1/1992 3/2/1992 4/1/1992 5/1/1992 5/31/1992

Temperature (degrees F)

Test Date

Test Operations Summary

Condition Test Events APU time (hours) Rotor time (hours)

Temperate 11 14.3 8.9

Cold 21 35.4 11.8

Hot 3 3.6 1.0

Rain 2 1.9 1.9

Wind 0 – –

Successes

• No effects on graphite/epoxy structure

• No hydraulic or oil leaks due to temperature

• Adequate cockpit heating and cooling

• Consistent APU starts after cold weather procedures were developed

• Drive system lubrication and engagement satisfactory

• Blade folding and unfolding demonstrated to -40 degrees F

• No avionics or flight control failures due to water intrusion or high temperatures

Cold Weather Problems

• Windshield cracking • Hydraulics fluid slow to warm • 15 A-hr battery is too small; pre-warmed 24 A-hr

battery required for starting APU at cold temperatures • Cabin floor too cold and automatic temperature was

ineffective • Engine fuel leaks during starting • Erroneous engine temperature sensor fault • Excessive ICDS bearing vibration at -65 degrees F • Proprotor damage during blade folding • Flight control computer failures at -4 degrees F

Hot Weather and Rain Problems

• ECS Controller failure

• Proprotor mast torque sensor failure in rain

Lessons Learned

• Vectored-thrust VTOL aircraft installation in the McKinley Climatic Laboratory

• Test operations

• Maintenance

• Project scheduling

• Off-duty

Vectored-Thrust VTOL Aircraft Installation in the Climatic Laboratory

• Exhaust gas collection over the full range of thrust vector angles.

• React thrust loads over the full range of thrust vector angles.

• Structural dynamics of the aircraft/installation. • Access for maintenance if the aircraft is installed at a

considerable height above the ground. • Fall protection for maintenance personnel if the aircraft

is installed at a considerable height above the ground. • Routine and emergency ingress/egress of aircraft crew

if the aircraft is installed at a considerable height above the ground.

Test Operations

• Shakedown runs are essential. Plan on doing several of them.

• Thrust limits at various thrust vector angles to avoid installation structural failure and wash problems.

• Limits on engine run time (particular at high power and low temperatures) because of finite supply of chilled refrigerant to cool the air in the chamber.

• Test cards, briefings, debriefings follow standard flight test procedures.

• Limit exposure of personnel to extreme conditions.

Maintenance

• Must be able to conduct maintenance on the aircraft while it is being temperature-stabilized (“soaked”) at extreme temperatures

• Commercial-grade equipment such as laptop computers and lifts don’t work at extreme temperatures. Options are to provide a suitable micro-environment (example: put equipment in insulated enclosure with a heater) or bring in the equipment into the test chamber for short periods only.

• Must have portable heaters because some maintenance cannot be done while wear mittens.

Project Scheduling

• Test window start and stop dates (when the aircraft can be installed in the chamber and when it must be removed) are unchangeable. Everything practical should be done to maximize the use of that unslippable window.

• Thorough planning involving all stakeholders is essential.

• Accomplish as much preparation as possible before coming to Eglin AFB.

• Bring aircraft to Eglin AFB early; accomplish as much preparation as possible before test window start.

Project Scheduling (cont.)

• Must include time (~2 days) to thermally stabilize (“soak”) the aircraft at temperature.

• Humans are less productive at extreme temperatures; maintenance tasks take longer.

• Having as complete an inventory of spares on-site as possible reduces the risk of wasting precious chamber time waiting to spares to be shipped to Eglin AFB.

• Two-shift maintenance and flight test/ground operations engineering support to maximize use of window

Project Scheduling (cont.)

• Schedule must include time for fluid changes and post-change leak checks if the hydraulic fluid and lubricating oil must be changed for extreme low temperature operation.

• Build-up (-down) technique to reach extreme temperatures.

• High-level planning schedule should include 50% contingency reserve.

• Plan should minimize the number of aircraft installations and removals.

• Include time in schedule for aircraft installation, non-airworthy instrumentation installation, instrumentation integration with Climatic Laboratory systems, shakedown runs and aircraft removal.

Off-Duty

• Naval Aviation Museum, NAS Pensacola (minimum of two full days!)

• Air Force Armament Museum, Eglin AFB

• USS Alabama, Mobile, Alabama

• Charter a fishing boat for the day

• Some of the best beaches in the world

• But you probably won’t have much spare time to enjoy these things!

Summary and Conclusions

• Complex and high risk (technical, schedule, safety) test program

• Challenges integrating a novel aircraft in a unique facility

• Extensive planning and preparation were essential

• Test results provided valuable input to EMD program

Dedication

• Brian J. James, Major, USMC • Sean P. Joyce, GySgt, USMC • Gary Leader, MGySgt, USMC • Gerald W. Mayan • Robert L. Rayburn • Anthony J. Stecyk, Jr. • Patrick J. Sullivan, CW4, US Army (retired)

20 July 1992