unclassified ad number limitation changes · with the xm35 armament subsystem (20mm automatic gun)...

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AD RDTE PROJECT NO. 1X141807D174 USAAVSCOM PROJECT NO. 68-31 USAASTA PROJECT NO. 68-31

ENGINEERING FLIGHT TEST

AH-IG (HUEYCOBRA) HELICOPTER EQUIPPED WITH THE XM35 ARMAMENT SUBSYSTEM

(20MM AUTOMATIC GUN)

FINAL REPORT

NEAL DONALDSON PROJECT ENGINEER

GARY C. HALL MAJ, TC US ARMY PROJECT OFFICER/PILOT

NOVEMBER 1969

DISTRIBUTION THIS DOCUMENT MAY BE FURTHER DISTRIBUTED BY ANY HOLDER ONLY WITH SPECIFIC PRIOR APPROVAL OBTAINED THROUGH THE CG, USAAVSCOM, ATTN: AMSAV-R-F, PO BOX 209, ST. LOUIS, MISSOURI 63166.

US ARMY AVIATION EDWARDS AIR FORCE B

TEST ACTIVITY , CALIFORNIA 83583

·•·

THIS DOCUMENT IS BEST QUALITY AVAILABLE. THE COPY

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REPRODUCE LEGIBLYo

DISCLAIMER NOTICE

The findings in this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.

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US military agencies may obtain copies of this report directly from DDC. Other qualified users shall request through the Commanding General, US Army Aviation Systems Command (USAAVSCOM), ATTN: AMSAV- R-F, PO Box 209, St. Louis, Missouri 63166.

REPRODUCTION LIMITATIONS Reproduction of this document in whole or in part is prohibited except with permission obtained through the Commanding General, USAAVS- COM, ATTN: AMSAV-R-F, PO Box 209, St. Louis, Missouri 63166. DDC is authorized to reproduce the document for United States Government purposes.

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RDTE PROJECT NO. 1X141807D174 USAAVSCOM PROJECT NO. 68-31 USAASTA PROJECT NO. 68-31

ARMY PRELIMINARY EVALUATION

AH-1G (HUEYCOBRA) HELICOPTER EQUIPPED WITH TOE XM35 ARMAMENT SUBSYSTEM (20MM AUTOMATIC GUN)

FINAL REPORT

GARY C. HALL MEAL DONALDSON MAJ, TC PROJECT ENGINEER US ARMY

PROJECT OFFICER/PILOT

NOVEMBER 1969

DISTRIBUTION

IMs document may be further distributed by any holder only with specific prior approval obtained through the CG, USAAVSCOM, ATTN: AMSAV-R-F, PO Box 209, St. Louis, Missouri 63166.

US ARMY AVIATION SYSTEMS TEST ACTIVITY EDWARDS AIR FORCE BASE, CALIFORNIA 93523

iii

ABSTRACT

The Army Preliminary Evaluation of the AH-1G (Hueycobra) helicopter equipped with the XM35 armament subsystem (20inn automatic gun) was conducted at Edwards Air Force Base, California, from 27 November to 20 December 1968 by the US Army Aviation Systems Test Activity. This evaluation consisted of performance and firing and nonfiring stability and control tests. Stability and control tests were also conducted with the turret ammunition bay doors open and loaded to simulate an evacuation mission configuration. No deficiencies were detected during this test program. The shortcomings detected during this test were: decreased range performance with the XM35 installed, fluctuation of airspeed indicator and altimeter during firing, adverse effects on the airframe during firing caused by blast pressure and/or vibration, awkward location of firing contact connector on gun, lack of a linker-delinker tool, and lack of boresighting and harmonizing instructions and equipment. The accuracy, standoff capability, dispersion, noise level and fire control system of the XM35 armament subsystem should enhance the mission capability of the AH-1G helicopter.

iv

FOREWORD

During the conduct of this Army Preliminary Evaluation at Edwards Air Force Base, California, calibrated instrumentation and an instrumentation technician were furnished by Bell Helicopter Company. Armament technical assistance was furnished by General Electric Company.

TABLE OF CONTENTS

INTRODUCTION 1

Background 1 Test Objectives 1 Description 2 Scope of Test 3 Methods of Test 3 Chronology 3

RESULTS AND DISCUSSION 4

General 4 Performance 4

General 4 Level [light Performance 4 Airspeed Calibration 5

Stability and Control 6 General 6 Static Longitudinal Stability 6 Static Lateral-Directional Stability 7 Dynamic Stability 7 Controllability 8

XM35 Pi ring 8 Velocity Never Lxceed (V^-g) Evaluation 9 Miscellaneous 9

Airspeed and Altimeter Pluctuations 9 Reliability of the XM35 9 Blast Deflectors 9 Standoff Capability 10 Accuracy 10 Dispersion 10 Noise Levels 10 Vibration and Blast Pressure 10 Maintainability and Turn-Around 'lime '; Fire Control System 12 Boresightlng and Harmonizing 12

CONCLUSIONS 13

dcneral 13 Deficiencies and Shortcomings Affecting Mission

Accomplishment 13

RECOMMENDATIONS 14

APPENDIXES 15

I . References 15 II . Test Data 16

III. Test Instrumentation 53 IV. Operating Limitations 54

V. Distribution 56

vi

INTRODUCTION

BACKGROUND

1. The XM35 armament subsystem was developed jointly by Bell Heli- copter Company and General Electric Company to enable the AH-1G to have greater standoff capability, better accuracy and more killing power than is available with the 2.75-inch folding fin aerial rockets (FFAR). This prototype system was evaluated during the Army Mili- tary Potential Test (MPT) in which the US Army Aviation Systems Test Activity (USAASTA) participated (ref 1, app I). The Iroquois Project Manager funded a product improvement program to qualify the subsystem on the AH-1G based upon the MPT results and the ENSURE requirement. On 14 June 1968, USAASTA was directed to conduct an Army Preliminary Evaluation (APE) of the AH-1G helicopter equipped with the XM35 armament subsystem (ref 2). During the contractor portion of the qualification program, many unanticipated problems were encountered with the high blast pressures of the SM195 gun. These problems resulted in lengthy delays in the overall qualification program. However, during the contractor portion of the program, measures were devised to overcome the blast pressure problems. On 27 November 1968, USAASTA began the APE at Edwards Air Force Base, California.

TEST OBJECTIVES

2. Test objectives were as follows:

a. To provide quantitative and qualitative engineering flight test data to serve as a basis for an estimate of the degree to which the aircraft is suitable for its intended mission.

b. To assist in determining the flight envelope to be used by Army pilots for future weapons subsystem development tests, service tests and operational usage.

c. To detect and allow early correction of deficiencies, as well as to provide a basis for evaluation of changes incorporated to correct deficiencies.

d. To provide aircraft performance data for operational use.

DESCRIPTION

3. The test aircraft, S/N 67-15532, is a FY 67 procurement production AH-1G tactical helicopter produced by Bell Helicopter Company and was designed specifically for the armed role. It is a tandem, two-place, high-speed helicopter with a two-bladed, door-hinge type main rotor and conventional antitorque rotor. A three-axes stability and control augmentation system (SCAS) is used in lieu of the stabilizer bar to improve helicopter stability and handling qualities. The test helicopter is powered by a Lycoming T53-L-13 turboshaft engine with a military power rating of 1400 shaft horse- power (shp) at sea level (SL) , standard day, static conditions. The power plant is limited to 1100 shp at 314 rpm rotor speed due to maximum torque limits of the main transmission.

4. The distinctive features of the helicopter are the narrow fuselage (36 in.), the stub mid-wings (with four external stores sta- tions) and the integral XM28 chin turret. The armament configurations are changed by varying wing stores and/or turret weapons. The pilot can fire all weapons in the stowed position. The copilot/ gunner operates the flexible turret and can also fire the wing stores in an emergency by use of the pilot override. For this test, the XM195 automatic 20 millimeter (mm) six-barrel gun was installed on the left-hand inboard wing stores station. The cyclic rate of fire is 650 to 850 shots per minute (spm). Ammunition is housed in bays one on each side of the lower fuselage extending from the aft cross tube rearward. The ammunition capacity is approximately 1000 rounds. With the armament system installed, the lateral center of gravity (eg) is approximately 2 inches left of center. This weapon system has been designated the XM35.

5. The flight control system is a positive mechanical type with conventional helicopter controls located in the pilot's aft cockpit. The copilot/gunner's forward cockpit is provided with conventional directional controls, sidearm collective and cyclic controls. Con- trol forces are reduced by hydraulic servo cylinders connected to the control system mechanical linkage. The hydraulic system is powered by dual transmission driven pumps. A synchronized elevator is used to improve longitudinal characteristics. The electrically operated mechanical force trim system, connected to the cyclic and directional controls, is used to induce artificial control feel and to provide positive control centering. Ausform armor protection is provided for the crew, engine fuel control and engine compressor section. A detailed description of the helicopter is contained in references 3 and 4, appendix I.

SCOPE OF TEST

6. This test program consisted of limited quantitative performance tests and qualitative and quantitative firing and nonfiring stability and control tests. Limited qualitative and quantitative stability and control tests were conducted at speeds up to 100 knots indicated airspeed (KIAS) with the turret ammunition bay doors open and loaded with ballast to simulate an evacuation mission. During the doors-open portion of the test, the doors were secured by a rigid brace in lieu of the standard flexible cable. Test conditions for each test are discussed briefly in the Results and Discussion section of this report, and the data are presented in appendix II.

7. The flight restrictions which governed this test are presented in appendix IV. A safety-of-flight release for these flight restrictions was issued by the US Army Aviation Systems Command (USA- AVSCOM) (ref 5, app I).

8. Thirty-six flights were conducted during this test at Edwards Air Force Base, California, for a total of 31 test hours during an elapsed calendar time of 24 days utilizing 17 working days.

METHODS OF TEST

9. The engineering flight test methods used are described briefly for each test in the Results and Discussion section of this report.

CHRONOLOGY

10. The chronology of this test program is as follows:

Test directive received 14 June 1968 Test aircraft received 18 November 1968 Tests started 27 November 1968 Tests completed 20 December 1968 Draft report submitted 29 January 1969

RESULTS AND DISCUSSION

GENERAL

11. Quantitative level flight performance tests were conducted in both the clean and the XM35 configurations. The clean configuration range data on this production meUel test aircraft were compared with clean configuration data on a prototype AH-1G undergoing Phase D testing. There was no significant difference in the performance characteristics of these two test aircraft. When compared with the clean configuration AH-1G, the XM35 equipped AH-1G presented a loss in specific range (average 7.5 percent). Optimum cruise speed was reduced approximately 15 knots for the conditions tested.

12. Firing and nonfiring stability and control tests were conducted in the XM35 configuration. Nonfiring stability and control tests were conducted with the turret ammunition bay doors open and loaded with 200 pounds of ballast each to simulate an evacuation mission (hereafter in this report referred to as the doors-open configuration.) No significant deterioration in AH-1G stability and control characteristics was noted except for an increase in vibration levels during firing tests. High vibration blast pressures during firing tests caused airframe cracks and loosened screws. The standard ship's system airspeed indicator and altimeter fluctuated during firing. The firing contact connector on the gun is located in an awkward position. A linker-delinker tool should be provided with the kit. No boresighting and harmonizing instructions or equipment was provided. Standoff capability, accuracy, reliability and dispersion appeared to be excellent.

PERFORMANCE

General

13. Level flight performance tests were conducted in both the clean and the XM35 configurations to determine the change in helicopter performance caused by the XM35 armament subsystem installation.

Level Flight Performance

14. Level flight performance tests were conducted to cover a range of selected thrust coefficients (Cj) which had been flown in previous performance tests on a prototype AH-1G helicopter.

S/N 66-15247. Two speed-power pclars were flown in the clean configuration and three in the XM35 configuration. The nominal conditions for these tests were a 324 rpm rotor speed, a 5000- to 10,000- foot density altitude (H^), a forward and aft eg and an 8000- to '.ilOU-pound gross weight (grwtj. A level flight summary plot showing a comparison of the clean and the XM35 equipped helicopter is illus- trated by figure 1, appendix II. Nondimensional summary plots are presented in figures 2 and 3, appendix II. The clean speed-power polars are presented in figures 4 and 5. The XM35 speed-power polars are presented in figures 6 through 8. Fuel flow information was obtained from the fuel flow specification chart, figure 9.

15. Data show that there is no difference between performance characteristics of the clean production and the prototype AH-1G helicopter.

lb. The XM35 configuration produced a significant decrease in level flight performance when compared with the clean configuration. Specific range was reduced 8.8 percent; and cruise airspeed was reduced 16.2 knots at 9000 pounds, a 5000-foot Hp and a 324 rpm rotor speed. A comparison summary is presented in table 1.

Table 1. Performance Comparison,

Gross Weight

(lb)

Specific Range Nautical Air

Miles Per Pound of Fuel Configuration (Clean) (XM35)

Cruise Airspeed Knots True Airspeed

Configuration (Clean) (XM35)

Specific Range Performance

Decrease (Percent)

7800 .2272 .2145

8400 .2206 .2050

9000 .2132 .1945

140.2 124.3

139.2 123.0

136.3 120.1

5.6

7.1

8.8

Airspeed Calibration

17. Airspeed calibration flights were conducted at an 8500-pound ^rwt, a eg location of 194.1 inches and a rotor speed of 324 rpm to determine the position error of the test (boom) and ship's standard airspeed systems. The ground speed course method was used up to 121

KIAS. From 95 to 168 KIAS, a US Army T-28B pacer aircraft with a calibrated airspeed system was used as an airspeed reference. The test results are presented in figure 10, appendix II.

18. The standard ship's system was not calibrated with the airspeed boom removed. Calibration is not considered to be valid for a standard production AH-1G without airspeed boom and is not presented. All data are based on the test airspeed boom calibration.

STABILITY AND CONTROL

General

19. Stability and control tests were conducted to define the effects of the XM35 armament subsystem and of open ammunition bay doors on the various stability and control characteristics of the helicopter.

Static Longitudinal Stability

20. The approximate conditions for these tests were a 324 rpm rotor speed, a 5000-foot Hp, a forward eg location and an 8100- to 9200- pound grwt. The control position requirements were determined as a function of airspeed during level flight performance tests. The helicopter was stabilized at various trim airspeeds in level flight, and data were recorded to determine the control positions. A con- stant thrust coefficient (Cj) was maintained during these tests by increasing altitude with fuel bum-off. The results of these tests are presented in figures 11 and 12, appendix II, for the clean configuration and in figures 13 through 15 for the XM35 configuration. The collective-fixed static longitudinal stability was determined by maintaining the fixed collective pitch control at a trim condi- tion and then recording control position requirements at stabilized increased and decreased airspeeds from the trim airspeed. The results of these tests are presented in figures 16 through 18.

21. For all conditions tested, longitudinal cyclic stick position gradients were stable. Forward cyclic displacement was required to maintain a higher airspeed, and aft cyclic displacement was required to maintain a lower airspeed. There was a trend noted which indicated that static longitudinal stick gradients decreased with increasing airspeed, but this trend was not objectionable to the pilot. No significant adverse effects on the static longitudinal stability characteristics were caused by either the installation of the XM35 armament subsystem or by the open ammunition bay doors.

Static Lateral-Directional Stability

22. The approximate conditions for these tests were a 324 rpm rotor speed, a 5000-foot Hp and an 8100- to 9000-pound grwt. These tests were conducted by stabilizing the helicopter at a trim airspeed in balanced, zero sideslip flight with collective pitch control fixed at the required trim setting. While maintaining a straight flight path with a trim airspeed, the sideslip angle was increased in in- crements. At each increment of sideslip, the control positions, helicopter attitudes and the sideslip angle were recorded. The test results are presented in figures 19 through 22, appendix II, for the XM35 configuration and in figures 23 and 24 for the doors- open configuration.

23. Static directional stability was determined to be positive from the directional control position gradients with sideslip angle (left pedal required for right sideslip and vice versa) at all conditions tested. Neither the XM35 nor the doors-open configurations caused adverse effects on the static directional stability characteristics of the helicopter.

24. The effective dihedral, as indicated by lateral control position gradients with sideslip angle, was positive for all conditions tested. Neither the XM35 nor the doors-open configuration caused significant adverse effects on the effective dihedral of the helicopter.

25. When operating the AH-1G with the XM35 installed and no balanc- ing store on the right wing, large bank angles were required to maintain zero sideslip at low airspeeds; and attempts t^ fly with the ball of the turn and bank indicator centered resulted in large sideslip angles. This situation could become a problem in low visibility or night operations. It is recommended that a caution note pertaining to the sideslip angles at low airspeeds be placed in the operator's manual (TM 55-1520-221-10).

Dynamic Stability

26. The approximate test conditions for these tests were a 324 rpm rotor speed, a 5000-foot HD, a forward eg and an 8500- to 9100- pound grwt. These tests were conducted by disturbing the helicopter from trimmed stable flight with a 1-inch, 1-second control pulse to simulate a gust input and by recording the resulting helicopter motions. The results of these tests are presented as typical time histories in figures 25 through 27, appendix II, for the XM35 configuration and in figure 29 for the doors-open configuration.

7

27. Analysis of these time histories indicates that neither of these configurations has any adverse effect on the short period damping characteristics of the helicopter for the conditions

tested.

Controllability

28. The approximate test conditions for these tests were a 324 rpm rotor speed, a 5000-foot ll[), a forward eg and an 8500- to 9000-pound grwt. These tests were conducted about all axes by recording the resulting helicopter motions following an abrupt step-type control displacement from trim. Response characteristics are summarized in figures 30 and 31, appendix 11.

29. No significant change in the AH-1C response characteristics was noted during this test.

XM35 PI RING

30. Firing tests were conducted to determine the stability and control characteristics of the helicopter while firing the XM35 armament subsystem. The approximate test conditions for these tests were a 324 rpm rotor speed, a 3500-foot Hp, a forward eg and a 9100-pound grwt. 'Hie helicopter was stabilized on the desired trim conditions, and the controls held fixed while firing the gun and recording resultant helicopter motions. Two typical time histories of aircraft reactions to XM35 firing are presented in figures 32 and 33, appendix II.

31. Reactions of the helicopter about the pitch, roll and yaw axes during 3- to 5-second firing bursts were small and had a negligible effect on the helicopter. This negligible effect applied to all flight conditions tested. The physical location of the 20mm gun on the left inboard wing stores station caused a linear rearward acceleration on the aircraft rather than significant pitching, rolling or yawing reactions. At no time were control margins inadequate or aircraft reactions objectionable due to the weapons firing.

32. During attempts to accurately engage a target, a very slight left yawing tendenc\ was noted. However, the yaw SCAS adequately corrected this tendency, and this characteristic did not significantly detract from the excellent system accuracy. Targets were accurately and consistently engaged from a 1000- to 3000-meter slant range at altitudes from 500 to 3S00 feet above the ground. No

8

detailed accuracy tests were conducted. Subsystem accuracy appears to depend solely on pilot proficiency and ability to accurately es- li.uate ranges. A discussion of other aspects of the 20mm armament iubsystem are included in paragraphs 54 through 44.

.clocitv Never Exceed (V.,,.) Evaluation ■ ML

33. Tests were conducted to evaluate the contractor established V'I^. These tests were conducted by climbing the helicopter to an approximate ll,5ü0-foot Hp and diving at V^JE until recovery was necessary. Vibration data were recorded throughout the dive. These tests were conducted at a forward eg, a 9000-pound grwt and a 324 rpm rotor speed, Tiio results of these tests, for various trim V^g points where vibrations were highest, are presented in figures 34 through 56, appendix II. At no point were the vibration levels considered excessive. The Vjyjp established by the contractor appeared to be realistic.

MISCELLANEOUS

Airspeed and Altimeter Fluctuations

34. The ship's standard airspeed indicator and altimeter flvtu- ated considerably during firing due to either blast pressures or vibration. These fluctuations should be reduced to a minimum.

Reliability uf the XM55

55. The XM35 appeared to be very reliable. No stoppages occurred during the test. Only two incidents occurred during firing of 4900 rounds. The first incident occurred at 1964 rounds fired when the ammunition inspection door retainer spring on the left ammunition can vibrated loose (either from blast effect during firing or from ammunition feeding through the ammunition can during firing). This incident did not cause a malfunction of the weapon. The second incident occurred at 5921 rounds fired when one end of the housing cover lock pin broke off and lodged in the bolt-clearing well caus- ing the bolt to drag as the weapon cleared. This incident did not cause a stoppage and was discovered during reloading operations.

«last Deflectors

36. The blast deflectors had been previously used for approximately 6670 rounds. Prior to firing tests, they were inspected in accord- ance with reference 5, appendix I, and found to be satisfactory.

Three blast deflector clamping bolts were replaced at 1964 rounds at the request of the General lilectric representative. The armament subsystem was inspected upon completion of the test program, and no discrepancies were noted.

Standoff Capability

37. Qualitatively, standoff capability with XM35 is increased considerably over the 2.75-inch rockets. Targets were consistently engaged accurately at the 3000-meter slant range at altitudes up to 3500 feet above the ground.

Accuracy

38. Although detailed accuracy tests were not conducted, it appears that subsystem accuracy depends solely on pilot flying proficiency and ability to accurately estimate ranges; and it is much more ac- curate than the 2.75-inch rockets.

Dispersion

39. Qualitatively, dispersion of rounds on the target appeared to be good.

Noise Levels

40. Qualitatively, the noise levels in the pilot's and copilot/ gunner's cockpits are comparable to those levels experienced in firing the XM28/XM129 twin 40mm grenade launchers. The noise levels are considered acceptable.

Vibration and Blast Pressure

41. Vibration and blast pressure during firing appeared to adversely affect the airframe and instrumentation of the aircraft. After 1964 rounds of ammunition were fired, the left wing tip fairing assembly, S/N 1560-560-1471, came off in flight during firing. It is believed that vibration during firing had caused the hinge pin to wear out. Action should be taken to eliminate the cause of these adverse effects on the aircraft.

42. Upon completion of firing 4900 rounds, the following discrepancies were noted on the aircraft:

a. Plug wires were broken off the gas producer Nj tachometer indicator.

10

b. The rpm warning light was found to have four broken wires.

c. The fuel quantity circuit breaker had popped.

d. Two rivets were missing in the left-hand side fuselage panel below the cockpit.

e. Numerous loose rivets were found in the left-hand side fuselage panel below the cockpit.

f. Two cracks were found in the left-hand side panel below the pilot's cockpit.

g. The accelerometer plug and wires were broken off (located behind the left-hand side panel below the cockpit).

h. The friction assembly on the cyclic stick had vibrated completely loose. No torque was evident on the pilot's cyclic stick friction assembly,

i. Numerous screws in the forward canopy door hinges had vibrated loose.

j. The nut plate on the left-hand side fuselage panel had broken off.

Maintainability and Tum-around Time

43. The following items were noted regarding maintainability and turn-around time:

a. Firing contact connector: Considerable difficulty and delay in turn-around time was experienced by the awkward location of the firing contact connector on the right top side of the gun. This connector should be relocated to the left side of the weapon in an easily accessible location.

b. Inspection port: An inspection port should be provided to observe that the ammunition is seated properly in the feeder.

c. Linker-delinker: A hand operated linker-delinker, 20iran, M26, P/N 77080853, should be provided with the subsystem to assist in linking and delinking ammunition during weapon system loading. This will decrease turn-around time.

11

Fire Control System

44. The fire control system (switching functions) in the test aircraft appeared to be adequate. It was not known if this control arrangement was the production configuration.

Boresighting and Harmonizing

45. No boresighting and harmonizing procedures are currently available. These should be provided in addition to any special equipment that may be required.

12

CONCLUSIONS

GENERAL

46. The following general conclusions were reached upon the completion of the Army Preliminary Evaluation of the XMi>5 equipped AH-1G helicopter:

a. The level flight performance characteristics of clean production and prototype AH-1G helicopters are essentially the same (.para 15).

b. The level flight performance of the clean AH-1G helicopter is reduced by the installation of the XM35 armament subsystem (para 16).

c. The XM35 armament subsystem does not significantly affect the stability and control characteristics of the AH-1G during firing or nonfiring flight (paras 19 through 32).

d. The stability and control characteristics of the AH-1G helicopter equipped with the XM35 armament subsystem are not adversely affected for the conditions tested with the turret ammunition bay doors open and loaded to simulate an evacuation mission configuration (paras 19 through 29).

e. The operation of the XM35 armament subsystem causes adverse effects on the airframe structural integrity and instrumentation of the aircraft during firing (paras 41 and 42).

f. The VNE established by the contractor for the XM35 equipped Atl-IG helicopter appears to be realistic (para 33).

DEFICIENCIES AND SHORTCOMINGS AFFECTING MISSION ACCOMPLISHMENT

47. No deficiencies were detected which would preclude acceptance of the aircraft in the XM35 configuration or in the doors-open configuration within the tested flight envelopes.

48. Correction of the following shortcomings is desirable for im- proved operation and mission capabilities:

a. Reduced performance due to installation of the XM35 armament subsystem (para 16).

b. Adverse effects on the airframe structure and instrumentation of the aircraft while firing the XM35 (paras 41 and 42).

13

RECOMMENDATIONS

49. The following recommendations are made to improve the XM35 equipped AH-1G helicopter for operational use:

a. Action be taken to reduce the adverse effects on the airframe structure and instrumentation of the aircraft caused by firing of the XM35 armament subsystem (paras 41 and 42).

b. The possibility of increasing performance capabilities by incorporating a fairing on the XM159 gun be explored (para 16).

c. The firing contact connector on the gun be relocated to the left-hand side to facilitate ease of maintenance and reduce tum-around time for reloading (para 43a).

d. An inspection port be provided to allow observation of proper seating of ammunition in the feeder (para 43b).

e. A linker-delinker tool be provided to facilitate loading of ammunition and reduce tum-around time (para 43c).

f. Adequate boresighting and harmonizing instructions and equipment be provided (para 45),

g. A caution note pertaining to the sideslip angles at low airspeeds be placed in the operator's manual (para 25).

14

APPENDIX I. REFERENCES

1. Letter Report, US Army Aviation Test Activity (USAAVNTA), Pro- ject No. 68-09, Engineering Flight Test of the AH-1G Hetioopter Equipped with the XM20 Armament Subsystem Automatic 20rm Cannon, March 1968.

2. Test Directive, USAAVSCOM, No. 68-31, "AH-1G/XM35 Army Prelimi- nary Evaluation," June 1968.

3. Technical Manual, TM 55-1420-221-10, Operator's Manual, Army Model, AH-1G Helicopter, April 1967.

4. Specification, 209-947-030, Bell Helicopter Company, Detail Specification for Model AH-1G Helicopter, Fiscal Year 67 Procure- ment, 1 August 1966.

5. Messages, USAAVSCOM, AMSAV-R-EF, 12-1313 and 12-1328, subjects: Flight Release for AH-1G Flight with Ammunition Doors Open, and Safety of Flight Release for the AH-1G/XM35 Configuration ATA PROJECT 68-31, 11 December 1968 (unclassified).

15

APPENDIX II. TEST DATA

16

fiouRE m. 1 LEVEL FLIOHT SOMttRT

AH-lQ/».35 U.S.A. S/M 67-1^32

DEXSITT ALTITÖDE- 5000 FEET ROTOR SPEED* 321» RPM

.26

• .2li

^ .22

It .20

.16

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81

160

150

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130

120

110

100 7000

CLBAI

ARMED (111-35)

CORVP 0BTAI1BP fBOM FIOTOIS 2 ARD 3

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ARMED (»-35)

7U00 7800 8200 8600 9000 (BOSS WEIOMT T LB.

9^00 9800

17

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PIOURE NO. 2 NUN-DINKRSIONAL LhvEL FI.IGHT PKRFDRIUMCl

AH-10/IM-35 USA S/M 67-15532

NOTES: 1. SHADED SYMBOLS OBTAINED FROM FIODRES 1* AID 5 2. OPEN SYMBOLS AID BROKEN LINE OBTAINED FROM FICWRES 6

THROOOH 8 3. SOLID LINE OBTAINED FROM PHASE D TEST DATA (USAAVNTA

PROJECT 66-06, AH-10 USA S/N 66-1521*7)

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52 2. OPH SIMBOLS AID BBOXEI LIME OBTAIMED fHOH 2 THÖWM 6

• 3. SOLID LIME OBTAIMED FROM PHASE D ^ TEST DATA (QSAAVMTA PBOJBCT 66-06,

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2b 28

26

2b

CM

50

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bb

U2

bo

38

36

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32

30

28

26

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/

38 bo b2 bb 16 b8 50 52 5b 56 58 60

CTX

19

101» <M /OkfßH) 7 11 (A

FIODRB K>. k ixfiL ruom mrom*a

IH-lO/feO* Ü.S.A. S/K 67-15532

(BOSS MBIOHr- 7925 LOW». CO. STiTBW- 199.6 DI (AFT) UT. CO. STATIOI- 0.0Ü IN (LT) DBHSITT ALTITD1B» 5160 FBT TSBUST OOKrnCIHIT» 0.001(590 OOlinaöRATIOR- CLKiM

.99 MAI. NAMPP- 1200

1100

1000

900

800

CO 700

600

5oo

CURVE OERIVBD FROM PIOURE 9

REOOMBailÄD CBBISB SPEKD

CURVE mivn FROM noorats 2 ARD 3

UOO 20 UO 60 80 100

TRUE AlRSPEEDi/KROTS

120 1U0 160

20

$00

FIOQRE NO. 5 LXTCL njORT PIRFORMANCE

AH-lQ/XM-3$ U.S.A. S/M 67-l$332

CROSS WSIQRT« 8317 LB LOW. CO. STATIOK- 19U.2 IN. (FWD) UT. CO. STATIOH« O.Olj IN. (LT) EOiSlTT ALTITUDE- 1065? FDCT HOTDF SPEED- 32h RPM THRUST OOEFFICIEKT- 0.005710 OONFIOORATIOK- GLEAM

.99 MU. NAMPP—x

1200

1100

1000

900

800

700

600

CORVtt DERIVED FROM PIOORE 9

REOOMMENDED- CKUISE SPEED

.25

.20

li .0$ 53 j

.00

CURVE DERI7BD PROM FIOURES 2 AND 3

Uoo 20 Uo 60 80 100

TRUE AIRSPEEIVv KNOTS

120 mo 160

21

FTGUP.E NO. 6 LEVEL fUOHT PERFORMANCE

AH-10/IM-35 U.S.A. S/N 67-W)2

OROSS WEICWT- 8205 LB LONO. CO. STATION- 193.7 IN (PWD) LAT. CO. STATION- 1.76 IN (LT) DENSITY ALTITUDE- ?97£ FEET ROTOR SPEED- 32h HFM THRUST OOEFFICIENT- O.OOlili^O CGNFIGURATIÜN-XM-35

1200

1100

1000

900

2 800 8

OT 700

60C

500

hoo 20 iiO

,99 MAX. NAMPP

CUKVE DERIVED PBDM FIOTÜE 9

HEOOMMENDED CRUISE SPEED

CURVE MRIVED FROM FIQURES 2 AND 3

.25

.20

.15 U

•io s^

.00

60 80 100 120

ThUK ADiSPEED-v KNOTS

IhO 160

22

nOÖRl 10. 7 LEV1L FUOHT fEUKUKKM

AH-10/IM-35 O.S.A. S/I 67-1^532

(BOSS WKÜHT- 8181 LB IDNQ. G.G. STATB«- 19U.2 IN (FWD) ULI. G.G. STATIOW" 1.77 11 (LT) DOTSITT ALTITUDE- UB95 FEET ROTOR SPEED- 32h RPM THRUST GOEmciEIT- 0.00Ji7OO (X)HFiaöRATIOH-I«-35

1200

1100

1000

900

800

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w TOO

600

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CÜR?E 1ZUIVED FROM nOÜRES 2 AND 3

.00

1Ö~ ' SO 100 120

TRDE AIRSPSED^ODTS "mo" ISO

23

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FIOUH*; NO. 8 IHB Kuam PUPWRMAMCK

AH-1Q/XM-3S '-'.S.A. S/N 6T-15532

08035 rtlÜHT- 839U LOMO. CO. STATION* 191.9 IN (FWD) UT. CO. STATION- 1.72 Di (LT) DKNSITY ALTITUDE- 791Ö FEET ROTOR SPEED- 32I4 :1PM THRUST OOBFYICiENT- 0.üüi>290 OONFIOC'KATION- XM--35

1200

1100

,99 MAI. NAMP

CO

1000

900

800

700

600

-IT OTR?E DERIVED FROM PIOURE 9

REOUMMSNDED -— TJIUISK SPEED 0

y

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CURVE DBUVED FROM FI0ÖRES 2 AND 3

Ä-'-O

UOO 20 uo 60 30 100

TftUE AIRSPEEi-KNOTS

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o -J ft,

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o

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to

—* I

« X

<

3

10 to

i

U

§ §

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25

■

is UJ i-i

FIGURE NO. 10 AIRSPEED CALIBRATION

AH-IG/XM-35 USA S/N 67-ISS32

GROSS DENSITY ROTOR WEIGKT LONG. CG. LAT. f.G. ALTITUDE SPEED CONFIGURATION

GROUND 8A35 194.0 O.Wl 1309 324 XM-35 PACED 8635 194.2 0.782 5999 324 XM-35

O GROUND SPEED COURSE USED AS

BOOM SYSTEM AIRSPEED REFERENCE D CALIBRATED PACER AIRCRAFT USED

AS AIRSPEED REFERENCE -» B~

; T • ■■

10

0 e—%—<6r-T9—■-«-

30 40 60 70 80 90 100 110 120 130 140 ISO 160 INDICATED AIRSPEH) » KMOTS

(CORRECTED FOR INSTRUMENT ERROR)

.

FIGURE NO. 11

CONTROL POSITIONS IN LEVEL FLIdHT AH-1G/XM-35 USA S/N 67-155331

GROSS LONG. G.G. LAT. G.G. DENSITY »»EIGHT STATION STATION ALTITUDE

LB INCHES INCHES FEET 7988 199.5 0.4 LEFT 4934

CONFIGURATION CLEAN o.oJ

\ X

H-. a u,

^60|

40

8 y ^ 20 a.

I i

Q M Z U) V] W

K

§ ol

KSOI

S 60f 9

3 40^ K

H -"ZO*

FULL COLLECTIVE STICK TRAVEL-8.63 INCHES

-«—e—e-

FULL DIRECTIONAL PEDAL TRAVEL«6.08 INCHES

O O o &~9 9 0——^-

..:.

,..^4-

.. ...

Ö £80|

\ g g P g 6(J i -§ 1 2 a ■J

-3 4«

5 tu CU £

j20l

260,

2Sis «I

o s*: u =3 z u cc &. O i-< «J 2 M E

i 20

1^ i d 20

FULL UTERAL STICK TRAVEL-9.49 INCHES

-e—© cr

FULL LONGITUDINAL STICK TRAVEL-9.49 INCHES

40 60 80 100 120 140 160

.

CALIBÄATBD AIHSPEBD - KNOTS

27

;

■T i

FIGURE NO .riO.JE-. CONTHOL POSITIONS IN iEVHlj f|i

AH-1G/XM-35 USA S/M 67-lSii

... .

• i

■i r

GROSS

WEIQKT

LONG. CG. UT. C.G. DENSITY

STATION STATION AiTlTUDE INCHES INCHES FEET 194.9 0.4 LEFT

-as i

rra—r-r

CmfflGURATION C

FIGUHL NO. 13 'XJNTKOi »»OSITiÜNS IN lEVfcL FLIOrr

AH-1G/XM-35 USA S/N 67-JSS32

CROSS WEIGHT

Lb

8169

LONG. G.C. STATIOK

INCHES 194.0

LAT. C.G. STATION

INCHES 1.70 LEFT

DENSITY ALIITUOE

FKbT A940

CONFIGURATION XM-35

CT 0.OOA7O

CL 3 Wh

| 40 H fi 5 Ü H H S UJ ■— Z -J to _ —i 10 -I c ■.,-'

^

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a. ; S 20

u & 80j 2 ? (—1 V I m o a. t WJ

»—I Uj -3 H H 3 S^ b;

u ..) Ul o U -J 4(1 t- S ci 5 < UJ U- -3 J.

FULL COLLECTIVE STICK TRAVEL=8.63 INCHES

TJ *

FULL DIRECTIONAL PEDAL TRAVEL=6.Ü« INCHES

<r -cr ■« ©—cr

I-ULL LAitRAL STICK TRAVEL-g^'J INDIES

<=> O fl> &- -e—«» Q- n Q fit » p

S 2d

-J Ö > < -. x fr- JT -, ■.»( k-l a. J- a g

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-'■■

: o

FULL LONGII DINAL STICK TRAVEL*9.49 INCHES

..r 60 80 100 120 140 160

. CALIBRATED MRSfEED - KNOTS

29

h

FIGURE NO. 14

CONTROL POSITIONS IN LEVEL FLIGHT AH-1G/XM-35 USA S/N 67-15532

GROSS

WEIGHT LB 8190

LONG. CG.

STATION INCHES 193.5

LAT. CG.

STATION INCHES

1.71 LEFT

DENSITY

ALTITUDE FEET 3038

CONFIGURATION XM-35 0.00445

58 UJ

U Ui

_; O

^60

U. A.

f- 5 Ul -I

OC 3 OJ U. S

40

20

s

FULL COLLECTIVE STICK TRAVEL«8.63 INCHES

•

1

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i

§

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60

40

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FULL DIRECTIONAL PEDAL TRAVEL-6.08 INCHES

JQ ©—® 9 o-

FULL LATERAL STICK TRAVEL=9.49 INCHES

-©—o © ©-

z < M

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u.

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40

20

E 0 20

FULL LONGiWDINAl STICK TRAVEL*9.49 INCHES

40 60 80 100 120 140 160

CALIBRATED AIRSPEED - KNOTS

FIGUR1: NO. 15

CONTROL POSITIONS IN LEVEL FLIGHT AH-1G/XM-3S USA S/N 67-15532

GROSS LONG. C.G.

WKIQIT STATION LB INCHES

8409 191.5

LAT. C.G. DENSITY STATION ALTITUDE INCHES FEET

1.64 LEFT 7857

_; i , , ;

■

CONFIGURATION

XM-35 0.00529

o-bO 3

LU J § >• B LL. | 40 G H 8 UJ f—< ^: _J Ji LU -4 20 —J 5 u —; rj a. PC u 3 u.

Q 0

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^ .-) ■U p u -i 40

x cc 5 < JJ Lu -J

«;

£ 520

560 -J 5 S < HH o 2

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2D

B iv Bl 3 P

? 20


© ß1-« ©-

FULL DIRECTIONAL PEDAL TRAVEL=6.08 INCHES

&—-4t UÖ- ©- -^—0. I

- • ■

FULL LATERAL STICK I1AYEL-9.49 INCHES

<i- ^ « O- -» ■! ' I

FULL LONGITUDINAL STICK TRAVELS.49 INCHES

40 60 80 100 120

CALIBRATED AIRSPEED KNOTS

31

140 160

ga UJ H r- M

• r z o H W Oi U- O u. u & -2

— 2; -.1 < W —) o u z> (U ü^ u. a. UJ

a.

GRQSS WEIGin

IB 872«

felO

§10

r- 70

60

50

•340

FIGURE NO. 16 SfTAi'IG LONGITUDINAL STABILITY

AH-1G/XJ4-55 USA S/N 67-15552

LONü CG, STATION

INCHtS 104^

IAT C.G, STATION

INCHES 1.66 LEET

DENSITY ALTITUDE

FEET S322

e«r 99h& **^fH~*

CONFIGURATION <y

XM.3S 0.00473

SHADED SYMBOLS DENOTE TRIM POINTS.

FÜLL DIRECTIKNAI PEDAL TRAVELS.08 INCHES

g^-a^* GO

A

:

(A O X ■■* a. o * w u. 2 "^ H '~1

ü ui 3 tu u u. " n

a. ? 3

z

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i

0,50 5

40

30

*20

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t. ^ 60 ai ■-;

g E !250 Dk.

£60

50

40

30 i

• 30 i- 0


00 0 »

HULL LATERAL STICK TRAVELS.49 INCHES

0 fcjj# -- ■- * ^ O O

A A A A A A

PULL lONGITUOINAL STICK TRAVEL«9.49 INCHES

Nu. Bag

o >>

. .

; ;

.

A A^

- 20 40 60 80 100 120 140 160 180 200 220 240

CALIBRATED AIRSPEED ^KNOTS

32

FIGURE NO. 17 STATIC LONGITUDIKAL STABILITY

AH-1G/XM-35 USA S/N 67-15SS2

GROSS WEIGHT

LB

8927

LONG CG. LAT G.G. DENSITY CONFIGURATIOW r STATION STATION ALTITVDE . T

INCHES

192.2

INCHES

0.730 LEFT

FEET

413S ;

Q □ tu QC

E

>

S **> —

S

öS Sä O a.

S52 a)

a. 10

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50

40

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TRACE INOPERATIVE SHADED SYMBOLS DENOTE TRIM POINTS.

FULL DIRECTIONAL PEDAL TRAVEL »6.08 INCHES


*-» *—■ im T~» *~t V V ▼ V V

FULL UTERAL STICK TRAVELS.49 INCHES


! ..

0 JO 40 60 80 100 120 140 160 180 299 220 240

CALIBRATED AIRSPEED^KNOTS .

:

FIGURE NO. 18

STATIC LONGITUDINAL STABILITY

AH.1G/XM-35 USA S/N 67-15532

GROSS LONG C.G. LAT C.G. DENSITY WEIGHT STATION STATION ALTITUDE

LB INCHES INCHES FEET

9253 194.4 0.73 LEFT 3010

CONFIGURATION

XM-35 DOORS OPEN

0.00502

5 5 H h <

g '.3

Q

a. 5

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SHADED SYMBOLS DENOTE TRIM POINTS.

S70

60 z Q f- TI a: u. O U< W a. -J

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FULL DIRECTIONAL PEDAL TRAVELS.08 INCHES

□ a boo

a a.

|

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40

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50

40

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20 40 60 80 100 120 140 160 180 200 220 240

CALIBRATED AIRSPEED ^KNOTS

34

FIGURE NO. 19

STATIC LATERAL-DIRBCTIOJIAI, STAHUTY AH-1G/XM-35 USA S/N 67-15552

GROSS LONG. C.G. WEIGHT STATION

LB INCHES

6183 193.9

►4

u O V) p w H UJ »-« CC

H tu < Q

^20

20«

LAT. C.G. DENSITY ROTOR CALIBRATED STATION ALTITUDE SPEED AIRSPEED INCHES FEET RPM KNOTS 1.78 5173 324 107.0

CONFIGURATION XM-35

20i

Q. P UJ

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60

40

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QO n t Q ^^


FULL LATERAL STICK TRAVEL«9.49 INCHES

FULL COLLECTIVE STICK TRAVELS.63 INCHES

QO O •—O 008

FUL DIRECTIONAL PEDAL TRAVEL=6.08 INCHES

20 10 0 10 20 LT RT

ANGLE OF SIDESLIP - DEGREES

FIGURE NO. 20 STATIC LATERAL-DIRECTIONAL STABILITY

AH-1G/XM-3S USA S/N 67-15552

GROSS LONG. CG. LAT. CG. WEIGHT STATION STATION

LB INCHES INCHES

8378 193.5 1.73 LEFT

DENSITY ROTOR CALIBRATED ALTITUDE SPEED AIRSPEED

FEET RPM KNOTS CONFIGURATION

3178 32A 158.0 XM-35

g nr.

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<

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■ee©

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s a. Hi Z

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£80

60

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FULL DIRECTIONAL PEDAL TRAVEL»6.08 INCHES

20 10 0 10 20 LT RT


FIGURE NO. 21

STATIC LATERAL-DIRECTIONAL STABILITY AH-lü/XM-35 USA S/N 67-15532

-1 'J ui

O M

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<

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5 u ^ u 2 u o:

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(..ROSS LONC. C.G. WEIGHT STATION

LB INCHES

9182 195.0

fe20.

Ui

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UT. C.G. DENSITY ROTOR CALIBRATED STATION ALTITUDE SPEED AIRSPEED

INüiES FEET RPM KNOTS CONFIGURATION

1.54 LEFT 9167 324 107.0 , i JCM-35

e-o o ♦ e o-&

FULL LONGITUDINAL STICK TRAVEL=9.49 INCHES

» o -e-^

FULL LATERAL STICK TRAVEL«9.49 INCHES

j> z a: ^ ZJ 60 H- o u. Jt

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FULL COLLECTIVE STILK TRAVEL»8.63 INCHES

Q O O • O O O

FULL IBJAL PEDAL TRAVEL*6.08 INCHES

20 10 0 10 20 l.T RT


37

EU a

s Q EU Ci

0

120

FIGURE NO. 22

STATIC LATERAL-DIRECTIONAL STABILITY

AH-1G/XM-35 USA S/N 67-1SS32

GRUSS LONG. CG.

WEIGHT STATION LB INCHES

8982 195.3

^20

LAT. CG. DENSITY ROTOR CALIBRATED

STATION ALTITUDE SPEED AIRSPEED INCHES FEET RPM KNOTS CONFIGURATION

1.58 LEFT 9167 324 156u0 XM-35

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yj o S z M O

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20 10 0 10 20 LT RT


MOJRIi NO. iU STATIC LATERAL-OtRBCTtONAL STABILITY

A1I-1Ü/.\M-3S USA S/N (17-1SS32

LUNG. C.G. STATION INCHES

192.9

LAT, C.G. STATION INCHES

0.914

DENSITY ALTITUDE

FEET

4850

ROTOR SPEED RPM

324


74.8

CONFIGURATION

XM-35 DOORS OPEN

(ZV

H20. —

o o o—»000

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4(11

FULL LATERAL STICK TRAVEL «9.49 INCHES

58 H at H ►-I u. L,

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40

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20 LT

10 0 10


20 RT

39

GRÜSS WEIGHT

LB

b20

S

tu

HI a

;2o

FIGURE NO. 24

STATIC LATERAL-DIRECTIONAL STABILITY

AH-1G/XM-55 USA S/N 67-15532

LQNG. CG. STATION

INCHES

193.i

LAT. C.G. STATION INCHES

0.75 LEFT

DENSITY AITITUDE

FEET

4850

ROTOR SPEED RPM

324


106.1

CONFIGURATION

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FIGURE NO. 30 LONGITUDINAL RESPONSE

AH-1G/XM-35 USA S/N 67-15532

o 3 SO

20

10

GROSS WIGHT 9091 9052 9231 8965

< w

g 110

20

§30

u 2 W)

^ I $ iiü I

eji 0

LONG. C.Q. 195.1 191.5 191.7 191.4

LAT.

CG. 1.56 0.75 0.84 0.87

DENSITY ALTITUDE 4755 5000 4690 5280

ROTOR SPEED 324 324 324 324

CONFIGURATION XM-35 XM-35

XM-35, DOORS OPEN

m-jVt DOORS OPEN

SYMBOL CALIBRATED

AIRSPEED - KNOTS

0 O

O

75.5 158.5 77.0

106.5

• i

u tu en

i a.

^30

20

10

10

20

§30 2 10 12

FWD AFT

LONGITUDINAL CYCLIC STICK DISPUCEMENT - INCHES*FROM TRIM

46

T UTIML CYCtIC StICK DI8PLACBMÖIT

47

f-i—I'lii' I'»)!'1—i—» , , , :

"■| I'l"'"! ! Kip -"-f i

i

t

i■■ — •"s. 1S122« _ ■ ** iMKUf mi m M n •i~' ^■^<V ■■Ml Bt 1 T^T^^ ^^L ' *

mam v

■

rv • ft 9 « s ■ ai • -

.. 1

1..

:. H • f Pit ■

,1. .

» R « * S A 3 * * % f A i 3 • r* H

UT

tuTman i « « 5 ä ti« 'BMU " 7 7

i^Ku

mu an smunatn

— ■

^ ^___-i_i-

•k-

FIGURE NO. 54 VNE EVALUATION

AH-1G/XM-35 USA S/N 67-15532

16000

U€0O

12600

16000 bi

| M 8000 H 3 E on

«000

4000

2000

S.L.

NOTES: 1. SOLID SYMBOLS DEMOTE SELECTED

TRIM POINTS.

2. NUMBERS UNDER SHADED SYMBOLS INDICATE 2/REV VIBRATION LEVEL(gs)

3. OPEN SYMBOLS DEMOTE V^ EVALUATION (ACCELERATTü DIVE)

O

(REP. TM 55-1520-221-10

WITH XM-159) N^

(REF. TWX NO. 12-1328 "SAFETY OF FLIGHT RELEASE FOR THE AH-1G/XM-35 PROJECT") S^

RIF. TK 55-1520- 221-10, W/0 XM-159)

60 80 100 120 140 160 180 200

CALIBRATED AIRSPEED ^ KNOTS

0.25

0.20

0.1S

o.ia

0.05

0.0 V)

«0.25

Sz H 50.20 , »-4 »-4

i | o-.is Ul tu

»go.10

«0.05 | So.o >

0.25

0.20

0.15

O.ifr

0.05

0.0 60

L _.

FIGURE NO. -3S V«. EVALUATION NE

AH-1G/XM-35 U.S.A. S/N 67-15532

COPILOT VERTICAL

AV«. GROSS WEIGHT=9270 LB. LONG. C.G. STATI0N=193.8 IN. (FWD) LAT. C.G. STAri0N=1.57 IN (LT) AVG. DENSITY ALTITUDE«8480 FEET ROTOR SPEED=324 RPM

O

o

80

1/REV. (5.4 CPS)

O

O

O O o#

o o 00 o o

2/REV. (10.8 CPS)

O

0 oo0 0

CO

4/REV. (21.6 CPS)

o

0

o 0 G o o o 0 o

0

100 120 140 160


51

180 200

FIGURE NO. 56 V^ EVAUÄTICR

AH-16/XM-35 U.S.A. S/N 67-15532 COPlLBT VfiftTICAL

0.25

0.20

0.15

0.10

0.05

0.0 ©

6/REV. (32.4 CPS)

O 0 0 0© 00o ©eP

0.25 ? ^0.20

^20.15 >— H

a, 5 130. io

05 g^O.

-o.o §

60

l/REV. (43.2 CPS)

0 © © O 0 OG %©

U.^ii

0.20

0.15 10/REV. (54.0 CPS)

0.10

0.05

0.0 at . „a 9 © o <? nQ© cr^p - — so 100 120 140 160 180 200


5?

APPENDIX III. TEST INSTRUMENTATION

ENGINEER'S PANEL

Free air temperature Fuel counter Oscillograph counter Oscillograph switch Standard system airspeed Standard system altitude

PILOT'S PANEL

Angle of sideslip Boom airspeed Boom altitude Control positions Normal acceleration Oscillograph counter Sensitive rotor tachometer

OSCILLOGRAPH

Angle of attack Angle of sideslip Collective stick position Copilot/gunner's vertical acceleration Delta torque Directional control position Lateral cyclic stick position Rotor blip Longitudinal, lateral and directional SCAS actuator position Longitudinal stick position Pitch, roll and yaw attitude Pitch, roll and yaw rates Rate of fire Throttle position Vertical eg acceleration

53

APPENDIX IV. AH-16 OPERATING LIMITATIONS

LIMIT AIRSPEED (VL)

XM35 Configuration

Zero to 170 KIAS at 6000-foot ilf) or below

Above a 6000-foot Ilf), the VL reduced 6.7 knots per thousand feet to 12,000 feet

Ammunition Bay Doors Open

Zero to 100 KIAS

GROSS WEIGHT/CENTER OF GRAVITY ENVELOPE

Do not exceed 9500 pounds

Forward center of gravity limit:

Fuselage station (FS") 190 at 7000 pounds or less

FS 192 at 9500 pounds with linear decrease to FS 190 at 7000 pounds

Aft center of gravity limit:

FS 201.0 up to 8270 pounds with linear decrease to FS 200.0 at 9500 pounds

SIDESLIP LIMITS

Eight degrees at 170 KCAS with linear increase to 20 degrees at 60 KCAS

NORMAL ACCELERATION

Maximum 3.5 g

Minimum -0.5 g

54

RPM LIMITS (Steady State)

Power on:

Engine rpm 6000 to 6600

Rotor rpm 294 to 339

TEMPERATURE AND PRESSURE LIMITS

Engine oil temperature 930C

Transmission oil temperature 110oC

Engine oil pressure 25 to 100 psi

Transmission oil pressure 30 to 70 psi

Fuel pressure 5 to 20 psi

Torque pressure 50 psi

T53-L-13 ENGINE LIMITS - INSTALLED

Normal rated (maximum continuous) 400 to 6250C

Military rated (30-minute limit) 625 to 6450C

Starting and acceleration (5-second limit) 6750C

Maximum for starting and acceleration 760oC

Torque pressure 50 psi

55

UNCLASSIFIED Security CI»i«ific«lion

DOCUMENT CONTROL DATA R&D (Smcurlty ctmiMillcmtion ot till», body of mb»lr*€l and Indexing annolmtlon mual 6g mntmrmd whmt tit* ovf// f porf It etmiglllodj

I ORIGINATING ACTIVITV (Corpormlt »ulhor)

US Army Aviation Systems Test Activity (USAASTA) Edwards Air Force Base, California 93523

aa. RCPOBT (CCURITV CL *$firic* TION

lb. GHOUP UNCLASSIFIF.n

J REPORT TITLE

ARMY PRHLIMINARY EVALUATION AU-1G (HUEYCOBRA) HELICOPTER EQUIPPED WITH THE XM35 ARMAMENT SUBSYSTEM (20 MM AUTOMATIC GUN)

4 OESCRIPTIVE Horts (Typ» ol npon and lnelu»l¥t daf) FINAL REPORT, June 1968 through November 1969

s SÜ THORIII (WIM HSm, mlddl» Inlllal, MM nam«;

NEAL DONALDSON, Project Engineer GARY C. HALL, Maj , TC, US Army, Project Officer/Pilot

a REPORT DATE

November 1969 Tm, TOTAL NO. OP

J2_ 7b. NO OP RCPI

•a. CONTRACT OR GRANT NO.

b. PROJECT NO

M. ORIGINATOR*» REPONT NUXaERItl

RDTE Project No. 1X1418G7D174 C.

USAAVSCOM Project No. 68-31 d.

USAASTA Project No. 68-31 •b. OTHER REPORT NOIS) (Any othar nuaiban Mar Mr

till» nport)

N/A

ba m»ml0i»d

10. DISTRIBUTION STATEMENT

This document may be further distributed by any holder only with specific prior approval obtained through the Commanding General, USAAVSCOM, ATTN: AMSAV-R-F, PO Box 209, St. Louis, Missouri 63166.

it. SUPPLEMENTARY NOTES 12. SPONSORING MILITARY ACTIVITY Commanding General US Army Aviation Systems Command, ATTN: AMSAV-R-F, PO Box 209, St. Louis, Missouri . ! Üüüd

The Army Preliminary Evaluation of the AH-1G (Hueycobra) helicopter equipped with the XM3S armament subsystem (20 mm automatic gun) was conducted at Edwards Air Force Base, California, from 27 November to 20 December 1968 by the US Army Aviation Systems Test Activity. This evaluation consisted of performance and firing and nonfiring stability and control tests. Stability and «"ontrol tests were also conducted with the turret ammunition bay doers open and loaded to simulate an evacuation mission configuration. No deficiencies were detected during this test program. The shortcomings detected during this test were: decreased range performance with the XM35 installed, fluctuation of airspeed indicator and altimeter during firing, adverse effects on the airframe during firing caused by blast pressure and/or vibration, awkward location of firing contact connector on gun, lack of a linker-delinker tool, and lack of boresighting and harmonizing instructions and equipment. The accuracy, standoff capability, dispersion, noise level and fire control system of the XM35 armament subsystem should enhance the mission capability of the AH-1G helicopter.

DD fMM I MOV •• 1473 UNCLASSIFIED

Security CUsairication

UNCLASSIFIED Security Classification

K EV WORD!

Army Preliminary Evaluation AH-1G (Hueycobra) helicopter XM35 armament subsystem (20nim automatic gun) Performance Firing and nonfiring stability and control Ammunition bay doors open and loaded Simulate evacuation mission No deficiencies detected Shortcomings detected

UNCLASSIFIED Security Classification

unclassified ad number limitation changes · with the xm35 armament subsystem (20mm automatic gun)...

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