CAD/PAD Laser Ignitability Programs at the Indian Head Division, Naval Surface Warfare Center Mr. Tom Blachowski Mr. Travis Thom Indian Head Division Naval Surface Warfare Center 2010 SAFE – Europe 30 - 31 March 2010
Overview Two laser ignitability programs will be discussed • NACES USRM (MK123 Mod 0/MK124 Mod 0) Effort U. S. Navy – NACES (Navy Common Aircrew Ejection Seat) USRM (Underseat Rocket Motor) Evaluate laser ignitability characteristics of USRM propellents • ACES-II Rocket Catapult Effort U.S. Air Force – ACES-II (Advanced Concept Ejection Seat) New alternative propellent development effort IHDIV, NSWC Current Capability to conduct other laser ignitability efforts
System Function NACES Ejection Seat Test – F-14 Configuration – 15 Sep 1989 – NAWC CL
System Function NACES Ejection Seat MK123 Mod 0 / MK124 Mod 0 Underseat Rocket Motor
Laser Ignitability Test Approach For all IHDIV, NSWC Laser Ignitability efforts, a consistent approach test methodology has been adopted • A Carbon Dioxide (CO ) laser is utilized to supply a uniform heat input 2 to the energetic material under test • For the IHDIV test methodology, four differing laser input power levels are established and then, by varying the laser input pulse duration, assessments of the Time to First Light and the 50% Ignitability Thresholds are completed • The “pass/fail” criteria for the 50% Ignitability Thresholds are a determined if a “Sustained” combustion or an “Unsustained” combustion reaction is apparent at the completion of the laser pulse
NACES Laser Ignitability Test Program • The primary objective of the NACES USRM effort was to evaluate any potential differences between the laser ignition thresholds for KU and Mechanite 19 double base propellents at ambient and at cold temperatures. • Specifically, this evaluation includes comparing both the 50% Ignition Threshold and the Time to First Light (or Ignition Delay) parameters at ambient and cold temperatures for the two propellents. • All tests were conducted at atmospheric pressure. • Cold temperature for this test series was defined as conditioning each sample to -75 F (-60 C) in the dewar and conducting the specific laser functional test within 15 seconds of the dewar and sample being removed from the chamber.
NACES Laser Ignitability Test Program Sample Sample Dewar Cover Dewar Cover Dewar Dewar Holder Holder
NACES Laser Ignitability Test Results Example of a “Go” Test Result Example of a “No Go” Test Result Unsustained Combustion Sustained Combustion The spatial power distribution from the laser was not uniform as evident in the “No Go” sample. However, this aspect was consistent throughout this test program.
NACES Laser Ignitability Test Results Time to First Light vs Laser Flux 100 Mechanite 19 (70°F) Mechanite 19 (-75°F) Time to First Light (ms) KU (70°F) KU (-75°F) 10 10 100 1000 Laser Flux (W/cm^2)
NACES Laser Ignitability Test Results Energy to First Light vs Laser Flux 10 Mechanite 19 (70°F) Mechanite 19 (-75°F) Energy to First Light (J/cm^2) KU (70°F) KU (-75°F) 1 10 100 1000 Laser Flux (W/cm^2)
NACES Laser Ignitability Test Results 50% Ignition vs Laser Flux 1000 Mechanite 19 (70°F) Mechanite 19 (-75°F) KU (70°F) KU (-75°F) 50% Ignition (ms) 100 10 100 1000 Laser Flux (W/cm^2)
NACES Laser Ignitability Test Results 50% Ignition Energy vs Laser Flux 100 50% Ignition Energy (J/cm^2) Mechanite 19 (70°F) Mechanite 19 (-75°F) KU (70°F) KU (-75°F) 10 10 100 1000 Laser Flux (W/cm^2)
NACES Laser Ignitability Test Results • As expected, both the KU and the Mechanite 19 double base propellents exhibited required significantly increased laser input power levels at low temperature to achieve sustained combustion. • And as expected, both the KU and the Mechanite 19 double base propellents demonstrated significantly longer reaction times at low temperature than the reaction times at ambient temperature. Both propellents experienced “quenching” events when tested at -75 F (-60 C) temperatures. “Quenching” is defined as a single test result where the input parameters (laser input power and pulse duration) resulted in a “Sustained Combustion” result; however, when the flame front reached the top of the brass sample holder, the reaction was halted.
NACES Laser Ignitability Test Results Ash Ash Unburned propellant Unburned propellant Brass sample holder Brass sample holder Example of a “Quenched” Test Result
NACES Laser Ignitability Test Results Sample Quenching Events KU Propellent Mechanite 19 Propellent 10W of 8 None of 9 20W of 10 None of 10 30W of 10 None of 9 40W of 10 of 9
NACES Laser Ignitability Test Summary • For both the Mechanite 19 and the KU double base propellents, significantly higher laser input levels were required to achieve sustained combustion and the Time to First Light (Ignition Delay) times were significantly longer at cold temperature that at ambient temperature • The Mechanite 19 propellent results exhibited higher standard deviations than the standard deviation of the KU propellent test results • The propellent “Quenching” event was unexpected and it has been recommended that further investigation into this event be conducted
ACES-II System Operation ACES-II Ejection Seat F-16 Thunderbird Ejection 14 Sep 03 Cockpit Video Pilot was not seriously injured
ACES–II System Operation Video of CKU-5C/A Test – F-15, 600KEAS, HMTF – 10 Jul 04
ACES-II System Test Operation CKU-5C/A Rocket Catapult Test – HMTF 18 June 2009
ACES-II System Test Operation CKU-5C/A Rocket Catapult Test – HMTF 18 June 2009
ACES-II System Components A - Advanced ACES-II C - Concept Ejection Seat E - Ejection S - Seat IHDIV, NSWC manufactured IHDIV, NSWC manufactured ACES-II Ejection Seat currently in use on USAF A-10, F-15, F-16, B-1, & B-2 aircraft
ACES-II System Function ACES-II Ejection Seat CKU-5C/A Rocket Catapult
ACES-II System Function • Gas Inlet at Breech Actuates CCU-22B/A Impulse Cartridge CCU-22B/A Impulse Cartridge • Dual Firing Pins and Primers Installed in the CKU-5C/A • BKNO Charge 3 • Composite Propellant Grain produces High Pressure • Internal Locking Mechanism releases Catapult Tubes • Catapult Extends Lifting Seat from Cockpit
ACES-II System Function • Catapult Gas Initiates Auxiliary Igniter • BKNO and Propellant Chips in Nozzles 3 High Density Polyethylene Cup • Rocket Motor Propellant Grain ignites and Produces Sustaining thrust • Catapult Booster Tube Separates and Remains in the Aircraft Rocket Thrust Exhaust
CKU-5C/A Catapult Effort Primary Objective of the Laser Ignitability effort for the ACES-II CKU-5C/A Rocket Catapult Alternative Propellent was: • To establish the 50% Ignition Threshold and Time to First Light values for each differing composite (HTPB) propellent configuration These data points provided the system design engineers a rapid, low-cost preliminary evaluation to various differing HTPB propellent configurations
CKU-5C/A Laser Ignitability Test Results Laser Spot Laser Spot Example of CKU-5C/A Propellent Example of CKU-5C/A Propellent “Sustained” Reaction - GO “Unsustained” Reaction – NO GO
CKU-5C/A Laser Ignitability Test Results Example of CKU-5C/A Propellent – “Sustained” Combustion
CKU-5C/A Laser Ignitability Test Results CKU-5 Laser Ignition Time to 50% Ignition 100 y = 7757.6x -1.0801 R 2 = 0.9989 (msec) 10 0020 Baseline 1 100 1000 Laser Power (watts/cm 2 ) Example of Typical Results of CKU-5C/A Propellent Testing
CKU-5C/A Laser Ignitability Test Summary Summary: Over 10 alternative propellent formulations were evaluated utilizing this laser ignitability methodology (800+ tests). One of these propellent batches (IHDIV S/N -0020) very nearly matched the Time to 50% Ignition performance of the older CTPB propellent Therefore, the Sensitivity (or the 50% Ignition Threshold) and the Reactivity (Time to First Light or Ignition Delay) of this new propellent batch very nearly matched the performance of the older CTPB propellent Based on this data, in addition to other elements, sub-components and full-scale CKU-5C/A Rocket Catapults, utilizing the new HTPB propellent were fabricated and tested at IHDIV, NSWC All of these test results, both sub-component and full-scale, demonstrated that the selected HTPB propellent was capable of achieving system requirements
Upgraded Capability 200W CO 2 Laser 200W CO 2 Laser New Laser New Test Cell Test Chamber Test Chamber
Conclusions • The IHDIV, NSWC Laser Ignition capability has successfully contributed to a series of design programs and on-going investigations • NACES USRM double base propellents (KU and Mechanite 19) exhibited consistent laser ignitability characteristics at ambient and at low temperature – “Quenching” effect requires additional investigation • ACES-II CKU-5C/A Rocket Catapult, utilizing new HTPB propellent, successfully introduced into fleet • The IHDIV, NWSC Laser Ignition capability has been upgraded and is being continually utilized to support a wide range of CAD/PAD efforts
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