Live Fire Testing of the F-22 (1995) / Chapter Skim
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4 SUFFICIENCY OF F-22 TESTING PLANS
4 SUFFICIENCY OF F-22 TESTING PLANS
Pages 44-82
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From page 44... ...
The aircraft has been designed to meet them, and its vulnerability assessment program has been structured accordingly. The following assumptions were made by the SPO in the live fire test program to replicate the threat: .
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From page 45... ...
Sufficiency of F-22 Testing Plans TABLE 4-l F-22 Threat Environment 45 Fighters Air-to-Air Missiles Surface-to-Air Missiles Current Mirage 2000 Gripen MiG-29 Fulcrum SU-27 Flanker Future New Fighters IOC by 2004 SU-35 Improved Flanker Rafale Eurofighter 2000 New (Notional) Fighters Available by 2014 Multi-role Fighter Interceptor IOC 2005-2008 Experimental Fighter Interceptor IOC 2010-2015 Reticle IR Seeker with CCM AA-NOB/D AIM-9M AA-7D Active-Radar Seeker AA-X- 12 AIM-120 Multi-element Seeker AA-11 PYTHON 4 MAGIC 2 Imaging IR Seeker AAM (IOCs in 2004)
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From page 46... ...
. The effects of multiple fragment hits are ignored (consistent with the current state-of-the-art of vulnerability analysis)
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From page 47... ...
OVERVIEW OF THE AIR FORCE VULNERABILITY ASSESSMENT PROGRAM The committee received extensive briefings on the vulnerability assessment program from representatives of the F-22 SPO during its visit to Wright-Patterson Air Force Base in January 1995. Those briefings and communications with the SPO provided the basic information evaluated in this chapter.)
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From page 48... ...
Areas of uncertainty were next mapped against the F-22 design and the results of the vulnerability assessment to identify test issues, areas of the aircraft that needed to be tested, and specific test hardware requirements. The enumerated F-22 live fire tests and locations of the test areas on the aircraft are shown in Figure 4 I.2 As a part of establishing its test program, the SPO made several assumptions (SPO, 199Sa)
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From page 49... ...
6D Win=, Leading Edge 6E Main Wheel Well 6F Wing, Attachment Bay 7 F-1 Fuel Tank 1 1 Aileron Bay 49 3 \ few 6A& 6C 1&2 \ Age \ 6D 1 \,~ ~ 6B & 6E Wk-~;~ (~ 6F 6B 4 &4A-C FIGURE 4-] Locations of the test areas.
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From page 50... ...
These tests would involve ballistic testing of actual AIM-9 and AIM-120 rocket motors with both protected and unprotected bays to determine the effectiveness of protecting the weapons bay against fires using ablative materials. EVALUATION OF THE VULNERABILITY ASSESSMENT PROGRAM This section evaluates the current test program.
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From page 51... ...
The uncertainty in predicting hydraulic ram effects3 in the integral tanks arid Me need for developmental testing of some of these structures were recognized. While the committee agrees that the F-22 structure is predominately of multiple load path design, there are some exceptions.
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From page 52... ...
Also, the aft fuselage booms that support the horizontal tails as well as some of the vertical tad! loads might be considered to be single load path even though Right Hand Aft Boom \~ Of I/ Elm ~ ~/ Pivot Shafts T eft Harld Torizontal Tail
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From page 53... ...
As discussed below, some live fire testing has been done, and more is planned, for this general area. When assessing the vulnerability of the structure to ballistic threats, it is necessary to consider the effects of other potential damage mechanisms in addition to projectile impacts.
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From page 54... ...
Live Fire Testing of the F-22 i/ Access Through Keelson Forward ~ U Rum Outboard ~1 committee is concerned that, if the inner wall were ruptured as a result of hydraulic ram, the second barrier could be penetrated and fuel could leak into the cockpit. Fire could then break out because of the various ignition sources in the cockpit.
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From page 55... ...
Verification of the final wing design is planned in a full-scale-w~ng live fire, residual-strength test program to be conducted between 1997 and 1998. This testing wall be performed at the Air Force's Wright Laboratory, where the wing will be fueled and have simulated Toads applied and air flowing over the wing during live fire testing.
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From page 56... ...
The damage did not appear to be severe enough to jeopardize flight safety should similar damage occur during an operational conflict. No further live fire tests and no residual strength tests are planned for this aft boom structure.
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From page 57... ...
Nevertheless, a major uncertainty is the prediction of damage due to hydraulic ram effects from a ballistic hit. The SPO has recognized this uncertainty and constructed a comprehensive live fire test program to uncover weaknesses in the design.
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From page 58... ...
. Although a hydraulic ram test is planned for the aft boom fuel tank area, the committee is concerned about the lack of a live fire test shot at Frame 6.
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From page 59... ...
projectiles or other ignition sources. Fire in dry bays around fuel tanks caused by projectile or fragment ignition of the fuel spurtback from penetration of the file!
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From page 60... ...
The F-22 filet transfer lines are located inside Me fuel tanks to reduce the chance of their being hit (SPO, 1995a)
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From page 61... ...
Dry bay fire protection tests are covered later in this chapter. Assessment There is a question of whether OBIGGS generates enough nitrogen to keep the fuel tank ulIage spaces inerted at all times.
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From page 62... ...
· - ~ I" - en ~ \ o / ~1 \ \ Hi.::.
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From page 63... ...
The classic aircraft vulnerability is a single-shot kill of multiple branches of redundant hydraulic, electric, or control systems. Early analysis of the F-22 showed such problems in the electric power distribution centers, the hydraulic system, and the flight control avionics and wiring.
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From page 64... ...
Analyses and Tests ~_ The flight control and auxiliary systems have been subjected to extensive analysis. Live fire testing has been conducted or is planned to explore many of these systems.
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From page 65... ...
Test data must then be incorporated into models suitable for vulnerability assessment. Weapons Bay and Ordnance Description and Attendant Vuinerabilities The F-22 weapons carriage system includes internal arid external weapons, missile launchers, and built-in weapons-Ioading equipment.
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From page 66... ...
Also, the vulnerability of the ordnance has not been Ally established. The ITCG/AS md Joint Live Fire Test Program require further funding to accomplish this task.
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From page 67... ...
The ITCG/AS and the Joint Live Fire Test Program should be funded to assure the completeness of data on the vulnerabilities of on-board ordnance. Engines Description and Attendant Vuinerabilities The F-22 is powered by two FIl9 low bypass ratio, afterbuming turbofan engines adjacently mounted at the rear ofthe aircraft.
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From page 68... ...
No live fire testing is currently planned under the F-22 program on the FIl9 engine or its unique components, although the Joint Live Fire Test Program has an unended test program for such engines. Assessment Modern engines are relatively vulnerable systems with little history of fullup, full-scale live fire testing.
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From page 69... ...
fuel tank, failure of the ejection system, and so forth. Fire in the cockpit area would certainly, if uncontained, result in loss of the aircraft.
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From page 70... ...
Vulnerability of the forward fuel tank to fire or explosion, and the potential impact on pilot or escape system, is discussed elsewhere in this chapter. The committee is not aware of arty planned live fire testing of crew or escape system vulnerability.
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From page 71... ...
The optical fire detection capability is provided by eight optical sensors located in each engine compartment and four optical sensors in the APU compartment. The fire protection module located in the integrated vehicle subsystem controller monitors and processes the status signals produced by the optical sensors to provide fire and fault information (SPO, 199Sa)
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From page 72... ...
Fire detection and suppression is provided for the left and right main landing gear wells and the left and right wing attachment bays aft of the main landing gear wheel wells. Detection and suppression is provided by a dry bay fire protection unit that combines an infrared optical fire sensor and a pressurized Halon-filled cylinder in an integrated unit (an agent to replace Halon is being sought)
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From page 73... ...
Test 6 will examine the synergistic effects of PAO liquid coolant fluid, reduced flammability hydraulic fluid, aircraft fuel, and electrical power in protected and unprotected, cluttered aircraft dry bays. Test 6 will also examine fire detection and extinguishing capability in protected aircraft dry bays of the F-22.
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From page 74... ...
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From page 75... ...
Test 6A will examine the synergistic effects of pressurized PAO coolant lines and PAO-cooled avionics modules and the adjacent powered electrical wiring in the F-22 forward fuselage lower avionics bays. The SPO indicated that it may use the prototype air vehicle fuselage in Test 6A and will include all sources of PAO fluid and electrical wiring in this test (Griffis, ~ 995a)
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From page 76... ...
At China Lake (Navy and Air Force personnel and a consultant to OSD were present) , members of the committee were briefed on recent and planned live fire test programs for Navy aircraft (Tyson and Wise, 1995~.
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From page 77... ...
verifying predictions derived from the current live fire test program and the models used, and (b) testing the effects on the overall vulnerability assessment brought about by configuration and mission changes through the years.
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From page 78... ...
These features include a structural design with largely multiple (redundant) load paths, inerted fuel tanks using OBIGGS, dry bay foam, double-walled barriers between the cockpit and fuel, redundant fuel pumps and cross-feed between tanks, multiply redundant electric power, redundant hydraulics and flight control actuators, separated triple redundant air-cooled mission computers, fault tolerant avionics, dual engines, and engine blade containment.
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From page 79... ...
. Conduct additional live fire testing to determine the `damage that can be expected from a hit in the Frame 6 aft boom attachment area.
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From page 80... ...
Flight Crew . Live Fire Testing of the F-22 Fund the ITCG/AS and the Joint Live Fire Test Program to assure the completeness of data on the vuInerabilities of on-board ordnance.
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From page 81... ...
Live Fire Test No. ~ I, F-22 Live Fire Test Plan, Live Fire Test of Aileron Dry Bay Fire Test Program.
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From page 82... ...
~ 995a. Combat Survivability F-22 Live Fire Test Program.
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