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The objective of this one-year program was to develop and demonstrate emission abatement technology sufficient to obtain a 50% overall reduction in gas turbine engine mass emissions (CO, CxHy, NOx and smoke) with no increase in any individual pollutant when tested over a typical Army light observation helicopter (LOH) duty cycle. The selected baseline was the Army T63-A-5A gas turbine engine combustor. Seventeen potential low-emission combustors, each incorporating one or more of the selected concepts, were tested to determine their emission performance. Experimental results indicated that several designs had the potential for meeting the program objectives. Two combustors selected for final experimental evaluation were the 'Prechamber' and 'Modified Conventional.' The low-emission feature in the 'Prechamber' combustor was premix/prevaporization. The 'Modified Conventional' combustor incorporated four low-emission features: airblast fuel atomization, delayed dilution, convection cooling, and variable geometry. Both of these combustors met the emission reduction objectives. Experimental results indicated that both of these liners can be developed to meet all other conventional T63 combustor requirements, i.e. , light-off, temperature profile, durability, etc. The estimated development time for the 'Prechamber' is longer than for the 'Modified Conventional.' However, the 'Prechamber' combustor has better emission reduction potential when both combustors are designed as either fixed or variable geometry combustors.

Consumable electrodes of the alloys were arc melted into a water- cooled copper crucible (skull casting) to produce a molten pool of the metal. The liquid metal was subsequently poured into tungsten interfaced shell molds. These molds were produced by the REMET process in which initial tungsten slurry dips provide the non-reactive refractory surface. Thirty-four molds are scheduled in the program to optimize shell design, mold preheat temperatures and, finally, to produce usable castings for the properties testing phase. Configurations include the fluidity pattern, stress rupture bars, oxidation- thermal fatigue paddles, and Lycoming first stage T55 turbine nozzle vanes. Columbium alloys WC-3015 and B-66 were selected for study. Practice pours of columbium alloy CB-752 and program pours of alloys B-66 and WC-3015 indicate that these materials can be melted and cast into threaded test-bar shapes. Surface quality and soundness of these preliminary castings were acceptable. Surface contamination was not detectable for two of the alloys and only slightly so for the third.

The purpose of the program is to determine the feasibility of investment-casting columbium alloys. Thirty-four castings are scheduled to be produced, using consumable-electrode arc-melting and tungsten interfaced molds to prevent mold-metal reaction. Phase I of this program concerns the optimization of mold design and preheat temperature. Phase II envisages the production of sound test specimens, followed by coating, and an environmental and mechanical testing effort., See also Quarterly progress rept. no. 3, AD711930.

The purpose of the program was to advance the technology of small Auxiliary power units, using the secondary power system requirements of a hypothetical fighter aircraft of mid-1970 as a goal and an auxiliary power system as a test bed for exploratory development. The APU was 10 in. in diameter by 24 in. long, and the design-point performance goal was 300 equivalent shaft horsepower at 2200F turbine inlet temperature and sea level, 130F ambient conditions. Other design-point goals included an 11:1 cycle pressure ratio, 55- lb/min bleed-air at 6:1 pressure ratio, and a total system weight under 200 lb, including the starting system. The program resulted in technological advancements in the axial-centrifugal compressor, including variable inlet guide vanes, uncooled 2200F combustion, an advanced radial in-flow cooled-turbine, uncooled columbium nozzles, and an advanced high-speed torque converter with lockup feature.

Verifying the reliability of engines for prolonged service life by conducting protracted tests for a given service life does not assure rapid rates of growth of service life. To accelerate the rate of growth of service life and check on the capabilities of engines for prolonged service life it is necessary to conduct accelerated tests according to a program which will assure equivalence of the loading of units and parts for a given service life. In the report the basis for a program of accelerated equivalent tests of engines, compiled from analysis of the factors that exhaust the service life of units and parts is given., Edited machine trans. of Problemy Prochnosti v Mashinostroenii (USSR) n10 p14-19 1970, by John Miller.

This volume (Part X) contains detailed descriptions and operating instructions for two computer programs, HLMHLT and REFINE. Together, these programs comprise a numerical method of solution of a model of combustion instability in aircraft engine afterburners and duct burners. The model was developed in Phase 1 and is described in AFAPL-TR-68-142, Part XII, Unsteady Combustion in Duct Burners, Propulsion System Flow Program (Dynamic), Phase 1, Final Technical Report. Computer program HLMHLT consists of a general acoustics analysis of cylindrical and annular ducts with heat addition and with acoustic losses (or gains) at the boundaries. This program is applicable to a wide variety of problems, including those involving unsteady combustion. Computer program REFINE determines the effects of unsteady combustion and through-flow on the basic acoustic characteristics of the duct. These effects are used to modify the results of the acoustics analysis provided by Program HLMHLT. (Author)

This volume, Part VIII of ten parts, contains detailed instructions for operation of the computer program described in Part VII of this report. The program computes performance for a fan/compressor for any specified bypass ratio. Program subroutine listings and example runs are also presented. Some results of the program and comparisons of program predictions with test data which are summarized in Part VII are discussed in greater detail in this volume. (Author), Prepared in cooperation with Northern Research and Engineering Corp., Cambridge, Mass., Rept. no. NREC-1133A-2 and Pratt and Whitney Aircraft, East Hartford, Conn. See also Part 7, AD-866 554 and Part 9, AD-866 555.

This part of the report describes the dynamic simulation used to evaluate the RA-5C accommodation control in accommodating potentially dangerous disturbances which might jeopardize the normal operation and compromise the performance of the propulsion system. A dynamic analysis is necessary to verify the effectiveness of an accommodation control concept in taking corrective action in response to a disturbance. (Author)

Part IX describes a theoretical investigation of combustion instability in aircraft engine augmentors. Included is a general description of the analytical model and its digital computer solution. The model determines the frequencies, amplitudes, and spatial distributions of self-excited pressure oscillations in an afterburner or duct burner. The results of a parametric investigation of combustion instability in two turbojet afterburners are also reported. Good agreement between computed and observed trends has confirmed the conceptual validity of the analytical model. The parametric study also confirmed the utility of the computer programs in evaluating design modifications for suppressing or eliminating combustion instability. The computer programs are recommended for use now in engine design projects, but more advanced treatment of some of the input quantities, in conjunction with experimental data, will doubtlessly refine the accuracy of the solution. (Author), Prepared in cooperation with Northern Research and Engineering Corp., Cambridge, Mass., Rept. no. NREC-1133B-1-Vol-1 and Pratt and Whitney Aircraft, Hartford, Conn. See also Part 8, AD-866 499 and Part 10, AD-866 556.

The analytic concept and capabilities of a computer program for predicting performance of a fan/compressor with arbitrary flow division are described in this volume, Part VII. It further presents comparisons of YTF-33 fan/compressor test data with program predictions. Finally, the results of parametric studies to evaluate the effects of the front fan and the splitter lip on the compressor performance at different bypass ratios are presented. It was concluded that the program is a valuable tool for predicting fan/compressor performance at off-design conditions, and for determining modifications that would improve performance. (Author), Prepared in cooperation with Northern Research and Engineering Corp., Cambridge, Mass., Rept. no. NREC-1133A-1 and Pratt and Whitney Aircraft, East Hartford, Conn. See also Part 6, AD-866 553 and Part 8, AD-866 499.

The textbook supplies the necessary information for planning the basic systems of a modern aricraft power plant with an air-breathing jet engine. The aspects of engine operation in an aircraft are compared with the conditions of its operation on a stand, and the general requirements that apply to the power plant and its systems are derived. Separate chapters are devoted to the fuel systems, air intake and exhaust systems, and systems for scavenging and engine cooling. (Author), Edited trans. of mono. Silovye Ustanovki Letatelnykh Apparatove s Vosdushno-Reaktivnymi Dvigatelyami, n.p., 1965 pl-261.

While the units and subassemblies can be assembled both in an assembly shop and in the assembly sections of the combined and machine-assembly shops, the overall assembly of an engine is done only in an assembly shop. The overall assembly of engines, just as the assembly of units, consists of the preliminary intermediate and final assembly operations. In the process of conducting these operations, a check is made of the mutual arrangement of the parts and units; the axial, radial and diametral clearances and fits are established. These must comply with the technical specifications for the overall assembly of engines. The report discusses the overall assembly of three types of gas-turbine engines (GTE), differing significantly in design of basic units; therefore the preliminary intermediate and final assembly processes differ in respect to the methods used in these processes. (Author), Unedited rought draft trans. of mono. Sborka Aviatsionnykh Gazoturbinnykh Dvigatelei, Moscow, 1969 p257-340.

During the quarter, two pours of alloy B-66 were made into fluidity molds having two tungsten layers. One pour was made into an unheated mold, and one pour was made into a mold preheated to 1160 F. Preheating of the mold resulted in greatly improved fluidity with no serious contamination. Based on the eight B-66 fluidity castings produced so far in this program, two-layer molds preheated to 1400 F were selected as the optimum for the production of Phase 2 test specimens and vanes. One additional pour of alloy WC-3015 was made in a one-tungsten-layer fluidity mold preheated to 1300 F. No improvement in fluidity was seen compared with previous preheated two-layer molds. Based on the eight WC-3015 fluidity castings made in this program, two-layer molds preheated to 1400 F were selected as the optimum for Phase 2. (Author)

In turbines operating at a variable rotational speed large variations in operating conditions are connected with large losses in energy. The losses in ordinary adjusting stages substantially affect the overall efficiency of the turbine irrespective of the partial recovery of heat in the subsequent stages. The present article describes the results of the theoretical and experimental investigation of double-rim control stages with the second rim by-passed at higher loads. The material refers to turbines in which the characteristic number of the adjusting stage varies within a wide range depending on the operating conditions. Graphs cover the internal efficiencies, relative heat drop across the by-pass, the relative magnitudes of the kinetic energy, and the peripheral efficiency., Edited trans. of Energomashinostroenie (USSR) v11 n9 p7-9 1965, by W. Pearson.

The major objectives of the program are to evaluate newly developed structural materials of potential Air Force weapons-system interest and then to provide data-sheet-type presentations of these data.

Hydraulic transmissions for railroad trains, consisting of a closed pair of gears, a reversing reducter and two coaxial hydraulic converters rotating in one direction, the pump wheels of which are mounted on a common shaft with all of the parts being enclosed in a single block are known to exist. The common shaft is connected to the engine. The turbine wheels are mounted on a common hollow shaft which encloses the pump shaft., Trans. of Patent (USSR) 209 520.