Program Planning Report, Project 1794 Extension Program

APRIL 1957 PROGRAM PLANNING REPORT PROJECT 1794 EXTENSION PROGRAM Prepared in accordance wit~ initial Statement of Work dated 18 December 1956 Revised 11 February 1957. Exhibit 1 identified 57MCP5901 SECURITY WARNING This doc.ument is intended solely for the recipient and such persons as have been delegated to use it in the course of their duty and may be used in connection with work performed for or on behalf of the United States Air Force. The transmission, unauthorized retention, destruction, or the revelation of its contents, in any manner, to any unauthorized person(s) is forbidden. Failure to comply with any of the above instructions is an infraction of the Canadian Official Secrets Act and is a violation within the meaning of the United States Espionage Laws, title 18, U.S. G. J sections 793 and 794. This copy has been issued by Avro Aircraft Limited, Malton. Copy No. -1 PROGRAM PLANNING REPORT PROJECT 1794 EXTENSION PROGRAM Prepared in accordance with initial Statement of Work dated 18 December 1956-Revised 11 February 1957, Exhibit 1 identified 57MCP590 1 Supplementary Agreement #3 Chief Design Engineer Special Projects Group Avro Aircraft Limited Issued by: Avro Aircraft Limited Malton, Ontario, Canada Approved by H.G. Moody y Engineering Manager Special Projects Group Avro Aircraft Limited The number of pages in this report including Security Warning Frontispiece, Table of Contents, Illustration sheets and Exhibits is 121. AVNO AINCNAFT LI/UITED PROJECT 1794 USAF PROJECT 1794 Sli'C~ li'T TABLE OF CONTENTS INTRODUCTION 3 DESIGN AND PERFORMANCE 4 AERODYNAMICS PROPULSION 6 STABILITY AND CONTROL 7 STRUCTURES REPORTS AND CONSOLIDATED WORK AND COST CHARTS COMPANY STATEMENTS LIST OF ILLUSTRATIONS Plan View and Section Through Aircraft Cutaway of Aircraft Structure Turbine -Compressor Assembly 1/ A. S . Viper Engine Installation Flame Tube and Final Nozzle Assembly Flow Distribution -Hovering and Ground Cushion Work Chart -Design and Performance Work Schedule Chart -Design and Performance Proposed 1/12 Scale Transition Model 1/6 Scale Model in Tunnel 1/ 6 Scale Model Proposed 1/12 Scale Transonic Reflection Plane Model 2 /25 Scale Air Intake Model 2/25 Scale Air Intake Model Proposed Changes to 2/25 Scale Model 1/40 Scale Sting Mounted Model 1 /40 Scale Sting Mounted Model 1/40 Scale Sting Mounted Model 1/23 Scale Supersonic Model 1/23 Scale Supersonic Model Proposed Changes to l/23 Scale Model 1/ 3 Scale No,zzle Rig 1 / 3 Scale Outer Wing Segment Test Rig LIST OF ILLUSTRATIONS (Cont'd) 26 1/5 Scale Air Intake Model 27 Intake Arrangement 43 28 Ground Effects Rig Ground Effects Rig 45 Work Chart -Aerodynami~s 46 Work Schedule Chart -Aerodynamics 47 Schematic of Propulsion Control System Viper Air Intake 52 Exhaust Fantail Test 37 Viper Air Intake and Exhaust Fantail Overspeed Rig 39 Balance and Overspeed Rig ./ Test House and Six Viper Test Rig 41 Combustion Entry Mach No. 42 Combustion Entry Pressure and Temperature - 43 Estimated Combustion Efficiency and Extinction Limits 62 44 Six Viper Test Rig with Outer Wing and Cockpit 45 Work Chart -Propulsion 4G Work Schedule Chart -Propulsion 71 49 Schematic of Shutter Control System 73 50 Frequency Response Rig No. l 77 51 Frequency Response Rig No. l 78 52 Schematic of Control System Mechanical Analogue LIST OF ILLUSTRATIONS (Cont Work Chart -Stability and Control Work Schedule Chart -Stability and Control Proposed Stressing Reports for P. V. 704 Proposed Stressing Reports for Design Studies Work Chart -Structures Work Schedule Cha-rt -Structures Consolidated Work Chart Manhour and Cost Estimates AI/RO AIRCRAFT LI/141TED PROJECT 1794 1. SUMMARY This document details a planned program for the further development of the Avro Aircraft Limited VTOL aircraft concept, designated Project 1794, with accompanying cost estimates and scheduling,, The program is prepared in accordance with initial Statement of Work dated 18 December 19 56, as revised ll February 1957, Exhibit 1, identified 57MCP'590l. The work proposed parallels the private venture construction of a flying pro- totype presently being undertaken by Avro Aircraft Limited, and data obtained from the latter program, as and to the extent called for in the above exhibit, will be reported as part of the USAF program. A consolidated work chart, in Section 8 of this report, illustrates the tie-in between the company program, designated P . V. 704 and that of the USAF. In order that the significance and context of this program may be appreciated, a brief description of P . V. 704 is given in the Introduction. Following this, the USAF program is presented under six headings and wherein the P. V. 704 planning is concurrently described. Work charts, costs, manhour requirements and scheduling down to and including three digit sub parts of the Statement of Work are also Funding required against the USAF program amounts to the sum of $1, 483, 847 in Canadian Funds. This sum includes $180, 0 00 for the supply of six ASV Viper 8 engines, and $430, 960 for the Design and Development of the Combustion and Fuel Systems as per Statement of Work sub part 1. 1. 7. Wind Tunnel costs are not included. The contract period wil l be twenty 1nonths, starting 1 Feb- ruary 1957, ending 31 October 1958. AVRO AIRCRAFT LI/IITITED PROJECT 1794 2. INTRODUCTION The Avro VTOL aircraft is essentially a proposal for a high performance supersonic aeroplane in which the entire interior of the wing is utilized for the propulsion system, air and gas flow, having also -due to the characteristics of the propulsion system and the wing planform - a VTOL- STOL capabihty. The concept was developed by Avro to its present form and was reviewed as to feasibility under a study contract with USAF AF. 33( 600) 30161 (supplemental agreement No l), which was completed i n July 1956. This development program, involves further tests to inves- tigate the potentialities of this type of aeroplane, with study of applicati.on to a weapon system, and supplements the Avro Aircraft Limited company program (P. V. 704) which covers the building of one flying prototype. L-rt order that the significance and context may be apprec- iated the general layout of P. V . 704 is given in Figs. 1 through 6 and described as follows: Fig. 1 i.s a plan and section drawing of the aircraft. It is 35. 5 ft. in dian1eter; stands about 2ft. off the ground, measures 7. 7 ft. from the lower surface to the top of the canopy; is approxim.ately symmetrical in section and is expected to weigh about 20, 000 lb. with 5, 700 lb. fuel. Six Armstrong Siddeley Viper turbo-jets -1, 900 lb. thrust, 2~ inch overall diameter, 570 lb. weight each -are mounted ra.dially in the wing, exhausting inward; and used as gas generators t o drive a pair of contra-rotating compressors by means of a radial in-flow turbine. (See the section cut- away Fig. 2). The 8 ft. diameter compressors (Fig. 3), which rotate slowly by comparison with conventional turbo-jets, draw air from the u per and lower intakes {Fig. 2) and force it radjally out through the wing between the Viper engines. Some o .. the a1r thrown out by the compressors is directed back to feed the Viper engines {Fig. 4). The air is diffused in the wing to a high pressu e at the Lame holders ( Fig. 1), where fuel may be added to augment the thrust, and is then exhausted through pneumatical" y AVRO AIRCRAFT LI/JITITED FLAME HOLDERS UPPER AND LOWER INTAKE OUTER WING INNER WING DIFFUSE-R SECTION PILOTS COCKPIT PROJECT 1794 AVRO AIRCRAFT Llfi/TITED PROJECT 1794 AIR INTAKE DOORS PILOTS COCKPIT (HOVERING CASE) FLIGHT CONTROL SHUTTERS TIE RODS EXHAUST DIFF-USER _ENGINE ACCESS PANEL UPPER INTAKE INNER WING FLAME TUBf LOWER INTAKE LOWER COMPRESSOR FIG. 2 CUTAWAY OF AIRCRAI:T STRUCTURE AVNO AIRCRAFT LI/JITITED LOWER BLADE A TTACHMENTS TOP AIR INTAKE ANNULAR FAIRNG CENTRE SHAFT INTAKE ANNULUS EXHAUST GAS OUTLET FIG. 3 TURBINE-COMPRESSOR ASSEMBLY BOTTOM WHEEL HUB AND BEARINGS- TOP TURBINE BOTTOM TURBINE PROJECT 1794 UPPER COMPRESSOR TURBINE BLADING LOWER COMPRESSOR AVRO AIRCRAFT LIMITED ENGINE SUP~ORT STRUTS PROJECT 1794 MAIN ENGINE MOUNTINGS FIG.-4 A.S. VIPER ENGINE INSTALlATION AVRO AIRCRAFT LIIHITED PROJECT 1794 controlled shut-ters or gills (Fig. 5) which direct the jet as it exhausts al around the aircraft periphery; either to raise the aircraft ver-tically off the ground or to propel i in forward flight. This control of the exhaust direction enables the jets to be used for manoeuvring and stabilizing the aircraft in all flight conditions, so that separate addi- tional controls are not required to cater for vertical take -off and hovering. Thus, for instance, to pull up the nose of the aircraft the pilot will control the shutters by means of a conventional stick control to direct the jet out of the top of the wing in the rear sec-tor and thrust the tail down, or to roll he will similarly direct the jet from the top of one wing and from the bottom of the other. For stabilizing, the main rotors and a differential pressure diaphragm at the front of the wing are used to sense when the aircraft pitches in a gust and use is made of the jet controls to correct~ it. Stabilization through the controls is essential on this aircraft since the centre of gravity is in the middle of the wing at half the chord from the leading edge, whereas the aircraft would only be stable in pitch without using the controls if the centre of gravity were about at the quarter chord position. The change in jet direction as the aircraft pitches performs the same function as the fixed stabilizer of a conventional aircraft.. For a detail explanation of the stabilizer system see Section 6. In operation, to take-off, all the shutters on the top of the wing are closed and the shutters on the bottom are opened wide. Without adding fuel to augment it, a total of about 20, 000 lb. thrust is produced by the jets pointing downward all around the wing together with the central nozzle; how- ever, this jet-around-wing configuration produces a power- ful take-of ground cushion so that the lift on the aircraft is, in fact, increased to possibly 30, 000 lb., and the aircraft rises to about 17ft. (Fig. 6) where the ground cushion effect falls off rapidly. For vertical take -off the thrust must be greater than the weight and thus without after- burning the fuel capacity will be restricted to approximately 3, 500 lb: if afterburning to 1200K proves feasible statically, approximately 30, 000 lb. thrust can be produced, or 45, 000 lb. lift within the ground cushion. It is envisaged that trans- ition to forward flight will normally be from the ground cushion. By operating a transition control the pilot leans the jets backwards gradually, to accelerate the aircraft, and raises the nose; with the thrust less than the weight, the aircraft can accelerate and rise into free air a short distance from the starting point. AVRO AIRCRAFT LI/IITITED EXHAUST NOZZLE FIG. 5 FLAME TUBE AND FINAl NOZZLE ASSEMBLY PROJECT 1794 AVRO AIRCRAFT LI/IITITED PROJECT 1794 FIG. 6 FLOW DISTRIBUTION -HOVERING AND GROUND CUSHION AVRO AIRCRAFT L.I/'141TED PROJECT 1794 In forward flight ram pressure is collected into the air ntake, which progressively increases the afterburning pressure ratio and thermal efficiency. For supersonic speed, augmentation wiU always be necessary and because of the large mass of air the impellers can handle, a very large thrust and high top speed is possible. The large installed thrust also leads to a high thrust-to -weight ratio which makes a very high ceiling possible. The efficiency of the airframe at supersonic speed appears good and that of the engine reasonable, so that a long supersonic cruise rang~ is also forecast. For landing, a fully vertical descent will usually be made, with or without thrust augmentation from a hot main jet. Transition to the landing condition from in-flight is similar to the take -off transition. The nose is raised and the jets transferred to the undersurface and leaned downward col- lectively to rapidly slow the aircraft down; as the speed falls close to zero the nose is lowered and the aircraft brought down into the ground cushion. The pilot must then close the throttle to reach the ground. Tests completed under contract AF33(600)30161 (Supplemental Agreement No 1 ), have largely confirmed the performance potential and basic feasibility predicted for this new type of aircraft and confirmed Avro Aircraft Limited in their resolve to risk the building of a prototype in the shortest possible time. The tests have also, however, inevitably shown up the need for further test work in certain areas. Additionally in this phase of work it is desirable to cover other areas not pre- viously investigated, such as the transonic speed range and the very low speed transition regime. Furthermore in the previous program effort was confined to design study of a research type aeroplane and it is also desirable to include study of the application of the aircraft to a weapon system in the next development phase. These considerations form the basis for the detail proposals which The work proposed is described under the following headings: (a) Design and performance. (b) Aerodynamics. AVRO A,RCRAFT LhWITED PROJECT 1794 (c) Propulsion. (d) Stability and controL (e) Structures. Every effort has been made to outline the proposed course of work in detail. It is however likely that in the course of a twenty month program additional items not now fore- seen will appear essential, and others now planned may become relatively unimportant. Any changes to the planned USAF program will be with the prior approval of the USAF and will be reported in the bi-monthly progress reports required in Section 8. These will also record any changes in the P. V . 704 program. AI/NO AIRCRAFT LI/HITED PROJECT 1794 3. DESIGN AND PERFORMANCE 3. l Design Study A de.sign study will be made to apply the Avro Aircraft VTOL design concept to one of the following# whichever is considered the most suitable: (a) Special reconnaissance weapon system. (b) Interceptor weapon system. (c) Fighter bomber weapon system. The study will include general assembly drawings, instal- lation drawings for equipment and stores carried and weight and performance data with supporting information. In addition, a general design specification for a USAF research aircraft based on P. V. 704 will be submitted. MIL-D-80 34 and MIL-C -50 11A will be used as a guide in presenting information. Design information will include investigation of the following: (a) The effect of temperatures on the structural strength and rigidity of the aircraft including the effect due to aerodynamic heating, gas generator exhaust and outer wing combustion. (It is antic- ipated that this will form part of the required stress analysis,. the ' SPoP,e of which_ls .deiined in more detail in SectiorlS .:t;f:t~t~ prqgram). (b) Crew escape procedures and systems. (c) The ground handling requirements of the aircraft including take-off and landing surface require- {d) The range of fuel stowage compartment temp- eratures, and the provision of suitable stowage conditions. (e) Cooling and pressurization requirements of crew equipment and structure. AVRO AIRCRAFT Llfi/TITED PROJECT 1794 (f) Performance trade data for the aircraft in respect of such items as range, payload, ceiling, maxi- mum speed, etc. It is generally understood that only information relevant to design proposals will be presented, whether for components, sub systems o or any other items; comprising a list of equip- ment with description and artist's conception drawings. Performance or design specifications for any new suggested items of equipment will not be included. It is, however, understood that the design study for the weapon system will include a model specification to the format outlined in specification MIL-I-6252, to the extent called for in MIL- It is visualized that drawings will be provided approximately as follows: (1) A three view_general-ar.ra11g.ement of the~complete aircraft tabling its leading particulars and a numerical list of the subsidiary study drawings. (2) A three-view arrangement containing an inboard profile of the aircraft, a diagram of the compon- ent breakdown, and a diagram illustrating internal flow of gases. {3) A geometry drawing of the complete aircraft defining major dimensions and wing l?rofile. (4) Drawings of the cockpit arrangement showing pilot's equipment and furnishings, instrument panels and consoles, aircraft and power plant controls, navigation and communications equip- ment, crew entrance and escape, cooling and pres suxization equipment. (5) Drawings of the engine installation showing air intake and gas exhaust system, auxiliaries gear- box arrangement, controls and services pro- (6) A drawing of the centra 1 turbine-compressor showing main shaft and bearings, fixed and .Sub Parts AVNO AIRCRAFT LIHAITED PROJECT 1794 rotating structures~ typical ring and blade assem- blies with adjacent stators and seals, and lubri- cation system. {7) A drawing of the centre aircraft structure show- ing integral fuel tank and mid wing assembly, including alighting gear and its attachments. (8} A drawing of the aircraft outer wing structure showing installation of combustor cans and acces 7- sories together with hot gas exhaust shutters. (9) A drawing of the aircraft upper and lower intake structure showing ramp and entry arrangement, hovering doors, internal vanes and cascades. (10) A diagram of the aircraft control system depic- ting the pilot s central control valveo trim and hovering valves J shutter valves and jac~s, after- burner valves, and associated pneumatic sys- (11) A diagram of the aircraft fuel system depicting tank pressurization, tank_interconn<1cts and vents, fuel filling arrangeme:rlts, anti ' G provisions, supply to engines and combu_stor systems. (12) Drawings showing ground handling arrangements including removable _co-wl:!:_ng S-.and .:access doors:~ engine replacement, turbine-compressor removal, a ircraft towing picketing and hoisting attachments, external charging connections. {13} A diagram showing electrical power source a