Matt308
Glock Perfection
And here's the YC-14 write-up from GlobalSecurity.org Part II -
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By December 1975, Langley had negotiated with Boeing to obtain full-scale data on a USB high-lift system. Boeing conducted full-scale powered ground tests of a complete YC-14 wing-flap-fuselage segment at its Tulalip test facility to evaluate the effectiveness and noise levels of its powered system. During the tests, sound levels and pressure distributions were measured by Boeing over the USB flap and the fuselage next to the flap. These data were made available to Langley under the special research contract. Langley's interest was stimulated in part by the fact that the engine nozzle of the YC-14 design incorporated a D-nozzle (a semielliptical exit shape), which differed from the high aspect-ratio rectangular nozzles that had been used at Langley in the full-scale Aero Commander tests previously discussed. With the full-scale YC-14 data in hand, Langley proceeded with a test program to determine the adequacy of subscale models to predict such information, including the development of scaling relationships required for the various technologies involved.
A 0.25-scale model static ground tests of the Boeing YC-14 powered lift system were conducted at the outdoor test site near the Full-Scale Tunnel for correlation with full-scale test results. The model used a JT-15D turbofan engine to represent the CF6-50D engine used on the YC-14. The tests included evaluations of static turning performance, static surface pressure and temperature distributions, fluctuating loads, and physical accelerations of portions of the wing, flaps, and fuselage. Results were obtained for the landing flap configuration over a range of fan pressure ratio for various ground heights and vortex generator modifications.
The USAF YC-14 prototype STOL aircraft, first flight tested in 1976, successfully implemented optical data links to exchange data between the triplex computers. Optical coupling was selected to maintain inter-channel integrity. Each sensor output is coupled t o the other channels so that each computer has data from each of the sensors. Identical algorithms in each computer consolidate the data enabling equalization and fault detection / isolation of the inputs. The computers are synchronized to avoid sampling time differences and to assure all computers are receiving identical data inputs. The optical communication medium was used to eliminate electromagnetic interference effects, electrical grounding loop problems, and the potential propagation of electrical malfunctions between channels.
The behavior of pressure fluctuations measured on the airframe of a prototype high lift jet transport (YC-14) are characterized in terms of a particular jet exhaust flow field idealization, jet mixing noise, and exhaust shock noise. Generalized spectrum shapes and scaling relations for peak level and frequency of peak level were developed, and the frequency is found to depend on jet exhaust velocity and aircraft velocity. Comparisons are made with near-field engine exhaust noise of a conventional jet, and results suggest that the same two exhaust noises are important for both aircraft types. Surface fluctuating pressure data are assessed, and results suggest that the jet mixing and exhaust shock noise source characterizations for the YC-14 have useful applicability to conventionally configured jets.
One quarter scale static ground tests of the Boeing YC-14 powered lift system were conducted for correlation with full scale test results. The 1/4 scale model utilized a JT-15D turbofan engine to represent the CF6-50D engine employed on the YC-14 advanced medium STOL transport prototype aircraft. The tests included evaluation of static turning performance, static surface pressure and temperature distributions, fluctuating loads, and accelerations of portions of the wing, flaps, and fuselage. Results are presented for the landing flap configuration over an appropriate range of fan pressure ratio as affected by several variables including ground height and vortex generator modifications. Static turning angles of the order of 60 deg were obtained. The highest surface pressures and temperatures were concentrated over the upper surface of the flaps in the region immediately aft of the upper surface blown nozzle.
Flow turning parameters, static pressures, surface temperatures, surface fluctuating pressures and acceleration levels were measured in the environment of a full-scale upper surface blowing (USB) propulsive-lift test configuration. The test components included a flightworthy CF6-50D engine, nacelle and USB flap assembly utilized in conjunction with ground verification testing of the USAF YC-14 Advanced Medium STOL Transport propulsion system. Results, based on a preliminary analysis of the data, generally show reasonable agreement with predicted levels based on model data. However, additional detailed analysis is required to confirm the preliminary evaluation, to help delineate certain discrepancies with model data and to establish a basis for future flight test comparisons.
The YC-14 prototype's first flight occurred on August 9, 1976. YC-14 and YC-15 airplane capabilities were evaluated in a flight test program at Edwards Air Force Base in early November 1976. By the end of April 1977, the very successful YC-14 Program had exceeded all its projected goals in terms of flight hours, test conditions accomplished, and data accumulated. The performance goals were met in terms of maneuvering, field length, and touchdown dispersion. Following the flight test program, Boeing demonstrated the YC-14 to U.S. forces in Europe, including an appearance at the Paris Air Show in June. The airplane impressed the crowds at the air show, performing maneuvers formally considered impossible for a medium-sized transport. After the European tour, the YC-14 arrived for a demonstration at Langley Air Force Base on June 18, 1977, where its outstanding STOL capability and crisp maneuvers stunned not only the Air Force observers but many of the NASA-Langley researchers who had participated in USB studies that helped contribute to the design and success of this remarkable airplane.
The YC-14 flight test program ended on August 8, 1977, exactly 1 year after it began. Unfortunately, the anticipated mission of the AMST did not meet with Air Force funding priorities at the end of the flight evaluations (the B-1B bomber was by then the top Air Force priority), and the AMST Program ended. In 1981, the Air Force became interested in another transport, one having less STOL capability but more strategic airlift capability than the AMST YC-14 and YC-15 airplanes. That airplane was ultimately developed to become today's C-17 transport. The two YC-14 prototype aircraft were placed in storage at the Davis Monthan Air Force Base, and one was later moved to the Pima Air Museum in Tucson, Arizona, where it is displayed next to one of the YC-15 aircraft.
______________________________________________
By December 1975, Langley had negotiated with Boeing to obtain full-scale data on a USB high-lift system. Boeing conducted full-scale powered ground tests of a complete YC-14 wing-flap-fuselage segment at its Tulalip test facility to evaluate the effectiveness and noise levels of its powered system. During the tests, sound levels and pressure distributions were measured by Boeing over the USB flap and the fuselage next to the flap. These data were made available to Langley under the special research contract. Langley's interest was stimulated in part by the fact that the engine nozzle of the YC-14 design incorporated a D-nozzle (a semielliptical exit shape), which differed from the high aspect-ratio rectangular nozzles that had been used at Langley in the full-scale Aero Commander tests previously discussed. With the full-scale YC-14 data in hand, Langley proceeded with a test program to determine the adequacy of subscale models to predict such information, including the development of scaling relationships required for the various technologies involved.
A 0.25-scale model static ground tests of the Boeing YC-14 powered lift system were conducted at the outdoor test site near the Full-Scale Tunnel for correlation with full-scale test results. The model used a JT-15D turbofan engine to represent the CF6-50D engine used on the YC-14. The tests included evaluations of static turning performance, static surface pressure and temperature distributions, fluctuating loads, and physical accelerations of portions of the wing, flaps, and fuselage. Results were obtained for the landing flap configuration over a range of fan pressure ratio for various ground heights and vortex generator modifications.
The USAF YC-14 prototype STOL aircraft, first flight tested in 1976, successfully implemented optical data links to exchange data between the triplex computers. Optical coupling was selected to maintain inter-channel integrity. Each sensor output is coupled t o the other channels so that each computer has data from each of the sensors. Identical algorithms in each computer consolidate the data enabling equalization and fault detection / isolation of the inputs. The computers are synchronized to avoid sampling time differences and to assure all computers are receiving identical data inputs. The optical communication medium was used to eliminate electromagnetic interference effects, electrical grounding loop problems, and the potential propagation of electrical malfunctions between channels.
The behavior of pressure fluctuations measured on the airframe of a prototype high lift jet transport (YC-14) are characterized in terms of a particular jet exhaust flow field idealization, jet mixing noise, and exhaust shock noise. Generalized spectrum shapes and scaling relations for peak level and frequency of peak level were developed, and the frequency is found to depend on jet exhaust velocity and aircraft velocity. Comparisons are made with near-field engine exhaust noise of a conventional jet, and results suggest that the same two exhaust noises are important for both aircraft types. Surface fluctuating pressure data are assessed, and results suggest that the jet mixing and exhaust shock noise source characterizations for the YC-14 have useful applicability to conventionally configured jets.
One quarter scale static ground tests of the Boeing YC-14 powered lift system were conducted for correlation with full scale test results. The 1/4 scale model utilized a JT-15D turbofan engine to represent the CF6-50D engine employed on the YC-14 advanced medium STOL transport prototype aircraft. The tests included evaluation of static turning performance, static surface pressure and temperature distributions, fluctuating loads, and accelerations of portions of the wing, flaps, and fuselage. Results are presented for the landing flap configuration over an appropriate range of fan pressure ratio as affected by several variables including ground height and vortex generator modifications. Static turning angles of the order of 60 deg were obtained. The highest surface pressures and temperatures were concentrated over the upper surface of the flaps in the region immediately aft of the upper surface blown nozzle.
Flow turning parameters, static pressures, surface temperatures, surface fluctuating pressures and acceleration levels were measured in the environment of a full-scale upper surface blowing (USB) propulsive-lift test configuration. The test components included a flightworthy CF6-50D engine, nacelle and USB flap assembly utilized in conjunction with ground verification testing of the USAF YC-14 Advanced Medium STOL Transport propulsion system. Results, based on a preliminary analysis of the data, generally show reasonable agreement with predicted levels based on model data. However, additional detailed analysis is required to confirm the preliminary evaluation, to help delineate certain discrepancies with model data and to establish a basis for future flight test comparisons.
The YC-14 prototype's first flight occurred on August 9, 1976. YC-14 and YC-15 airplane capabilities were evaluated in a flight test program at Edwards Air Force Base in early November 1976. By the end of April 1977, the very successful YC-14 Program had exceeded all its projected goals in terms of flight hours, test conditions accomplished, and data accumulated. The performance goals were met in terms of maneuvering, field length, and touchdown dispersion. Following the flight test program, Boeing demonstrated the YC-14 to U.S. forces in Europe, including an appearance at the Paris Air Show in June. The airplane impressed the crowds at the air show, performing maneuvers formally considered impossible for a medium-sized transport. After the European tour, the YC-14 arrived for a demonstration at Langley Air Force Base on June 18, 1977, where its outstanding STOL capability and crisp maneuvers stunned not only the Air Force observers but many of the NASA-Langley researchers who had participated in USB studies that helped contribute to the design and success of this remarkable airplane.
The YC-14 flight test program ended on August 8, 1977, exactly 1 year after it began. Unfortunately, the anticipated mission of the AMST did not meet with Air Force funding priorities at the end of the flight evaluations (the B-1B bomber was by then the top Air Force priority), and the AMST Program ended. In 1981, the Air Force became interested in another transport, one having less STOL capability but more strategic airlift capability than the AMST YC-14 and YC-15 airplanes. That airplane was ultimately developed to become today's C-17 transport. The two YC-14 prototype aircraft were placed in storage at the Davis Monthan Air Force Base, and one was later moved to the Pima Air Museum in Tucson, Arizona, where it is displayed next to one of the YC-15 aircraft.
Another time where my mind and my fingers are not cooperating.