The Saunders-Roe SR.177 Falcon in RAN service

[rickshaw]

The Saunders-Roe SR.177 Falcon in RAN service

In 1952, Saunders-Roe had been awarded a contract to develop a combined rocket-and-jet-propelled interceptor aircraft, which was designated as the Saunders-Roe SR.53. However, as development work on the project progressed, the shortcomings of the design became increasingly evident. Most particularly, as with the German rocket-powered interceptors of the Second World War, the range and endurance of such an aircraft were limited by the high rate of fuel consumption by the rocket engine. However, as turbojet engines developed and became increasingly powerful and efficient, new powerplants were quickly becoming available that would make such aircraft more practical.

Maurice Brennan, the chief designer of the SR.53, had also become convinced of the necessity for an airborne radar unit to be carried by the aircraft, as the SR.53 was reliant upon on ground-based radar guidance and the pilot's own vision to intercept aircraft. In particular, it was feared that pilots would be unable to focus their eyes properly at the 60,000 feet (18,000 m) altitude that the SR.53 was capable of. Out of a combined desire to equip the aircraft with a radar unit and to make greater use of turbojet power, a more ambitious design began to be drawn up. While it had begun as an advanced design concept for the SR.53, upon the issuing of a development contract by the Ministry of Defence in May 1955 (to meet specification F.155), the project was given its own designation as the SR.177.

As work continued on the SR.53, a separate High Speed Development Section was formed by Saunders-Roe to work on the SR.177. Initially, the SR.177 was a straighforward development of the SR.53, sharing much of the same configuration and equipment, and it was envisioned that the first test flight would take place during the first half of 1957. However, in February 1955, an extensive redesign of the SR.177, with the aim of making the type suitable for use by both the RAF and the Royal Navy, was commenced. Of the changes made to the aircraft, major differences included the repositioning of the jet engine to the lower fuselage lobe, which was now fed with air via a large, chin-mounted intake; the wing was also enlarged and blown flaps were adopted. The turbojet engine selected was the de Havilland Gyron Junior, capable of generating 8,000 lbf (36,000 N) of thrust.

Project launch

In September 1955, Saunders-Roe received instructions to proceed on the SR.177 from the British Ministry of Supply. The Ministry also gave instruction for the production of mock-ups, windtunnel tests, and the development of construction jigs for the manufacture of an initial batch of aircraft. From the onset, the SR.177 faced competition in the form of an enlarged derivative of the Avro 720, which had itself been devised as a competitor against the smaller SR.53. Avro promoted the 720 to the Royal Navy, hoping to win favour away from the SR.177, which was by this point had reached the detail design phase. The Ministry ultimately opted to cancel all work on the Avro 720, primarily as a cost-saving measure, as well as to concentrate development work on HTP-based rocket motors, such as those powering the SR.53 and SR.177.

The most significant difference between the SR.53 and SR.177 was the latter's use of a jet engine with nearly five times the thrust of the one adopted for the former. While the SR.53 had relied mostly on its rocket engine for climbing, the SR.177 would be able to add considerable endurance by conserving use of its rocket for the dash towards a target only. It was expected that the added endurance would allow the SR.177 to perform roles other than pure interception; these roles were expected to include strike and reconnaissance missions. The SR.53 design had been considerably enlarged to accommodate the new engine, and the original sleek lines were forfeited for the chin-mounted air intake.

Following the maiden flight of the SR.53 in May 1957, the development of the SR.177 became the main focus of activity at Saunders-Roe. At this point, the project was viewed as having considerable large scale potential, as both the RAF and Royal Navy appeared to be set to be customers for the SR.177. The RAF sought to operate it alongside the incoming English Electric Lightning interceptors while, according to aviation author Derek Wood, the Royal Navy also had considerable interest in the programme. When the development contract had been issued in May 1955, it reflected this dual interest. The Navy's requirements were defined in NA.47 while the RAF's requirements were specified in OR.337, which had been issued by the Ministry of Supply as Operational Requirement F.155. There was optimism that a joint aircraft for the two services could be developed, saving considerable expense, time, and effort.

Negotiations on the exact number of aircraft sought by either service were protracted; but it had been established that there was demand for an initial batch of 27 SR.177 aircraft, and that sufficient tooling should be produced to enable the programme to transition rapidly to full-rate production.  By April 1956, a consensus had emerged that, in order for the first five SR.177s to be completed by January 1958, these aircraft would be produced without any A.I. radar or the ability to support armaments. In July 1956, funding was secured for 27 aircraft to be produced, the first of which being expected to fly by April (later postponed to October) 1958. On 4 September 1956, a formal contract for the 27 aircraft was issued, which was sub-divided into four batches of five, four, four, and fourteen respectively, although the final eighteen were subject to evaluation and were thus pending confirmation. During 1957, a development contract for the SR.177 was announced for its use with the Royal Navy.

By January 1957, the design of the main component jigs was 70 per cent complete while the component assembly jigs were almost 50 per cent complete; the manufacture of a quantity production batch was nearing, which would have likely been subcontracted to another aviation company due to the high level of workload at Saunders-Roe's Cowes facility.  Armstrong Whitworth, who had already taken over work on the basic wing design of the SR.177, had been selected as the second production outlet for the type. The selection of a production center for the SR.177 was complicated by a favourable event; interest in the programme from the West German government. Since 1955, the revived German Air Force had sought a suitable high performance aircraft to equip itself with, and there were hopes that the SR.177 could become the foundation of a collaborative European fighter programme.

The German Defence Ministry had first expressed interest in the SR.177 in October 1955; in February 1956, the British Government Committee on Security consented to discussions being held on the SR.177. The prospects of a large German order for as many as 200 aircraft, and for the SR.177 to be manufactured under licence in Germany by the recovering German aircraft industry, were soon being aired, of which the British government declared its openness towards. In January 1957, the Anglo-German Standing Committee on Arms Supply reported that General Kammhuber, the Commander-in-Chief of the German Air Force, was concerned that, due to a lack of available financing until Aprril 1958, the delivery timetable may not be satisfactory. According to Wood, Germany was keen to issue an order as soon as possible by this point, which they did.  They ordered  194 aircraft from Armstrong Whitworth who were contracting on behalf of Saunders-Roe.

With the German order other nations started to take increased interest in the SR.177 design.  After Germany, Belgium ordered 48 aircraft, Holland another 60.  From outside Europe, the Royal Australian Navy's Fleet Air Arm, anxious to move out of the piston-engined era at last, ordered 36 for service aboard its light fleet carriers, HMAS Sydney and Melbourne.    The Royal New Zealand Air Force ordered 24.  The South African Air Force ordered 60.   The SR.177 was a success commercially, with the total ordered by the RAF (200) and the RN FAA (80).   It served successfully in the Interceptor, Reconnaissance and Fighter-Bomber roles.  Its only combat use was by the RSAF against black rebel groups fighting the Apartheid regime, where it was used to drop bombs and fire unguided rockets.














The Model

The model is the Freightdog SR.177 model.  I added a spare arrestor hook under the rear fuselage and raided the decals box for RAN roundels and titles.   It was pained with a hairy stick using Tamiya flat paints and then Future'd. 

[zenrat]

Ugly little bugger isn't it?
Good job.

[TomZ]

Looks nice.
Could do with an extra light when taking the picture though.......

TomZ

[NARSES2]

Looking good mate 

[DogfighterZen]

Ugly little bugger isn't it?
Good job.

I agree, not the prettiest design but that's nice work, the scheme looks good on it.