View source for Saunders-Roe SR.53

{{Short description|Interceptor aircraft in the Royal Air Force}}
{{redirect|SR 53|State Route 53 or State Road 53|List of highways numbered 53 (disambiguation)}}
{{Use dmy dates|date=December 2023}}
{{Use British English|date=December 2023}}
{{Infobox aircraft
  |name = SR.53
  |image = Saunders Roe SR.53 XD151 FAR 08.09.57.jpg
  |caption =The second SR.53 on display at the September 1957 [[Farnborough Air Show]]
  |type = Interceptor
  |manufacturer = [[Saunders-Roe]]
  |designer =[[Maurice Brennan]]<ref>Wood 1986, p. 57.</ref>
  |first_flight = 16 May 1957
  |introduction =
  |retired =
  |status = Experimental
  |primary_user = United Kingdom
  |more_users =
  |produced =
  |number_built =2
  |unit cost = 
  |developed_from =
  |variants = [[Saunders-Roe SR.177]]
}}

The '''Saunders-Roe SR.53''' was a British prototype [[interceptor aircraft]] of mixed [[Jet engine|jet]] and [[rocket]] propulsion developed for the [[Royal Air Force]] (RAF) by [[Saunders-Roe]] in the early 1950s.<ref name="Flight, 24 May 1957, Mixed Power Intercepter" >{{citation |url=http://www.flightglobal.com/pdfarchive/view/1957/1957%20-%200691.html |title=Mixed Power Intercepter. |journal=[[Flight (magazine)|Flight]] |number=2522 |volume=71 |date=24 May 1957 |pages=697–700}}</ref> As envisaged, the SR.53 would have been used as an [[interceptor aircraft]], using its rocket propulsion to rapidly climb and approach incoming hostile bombers at high speeds; following its attack run, the aircraft would then return to its base using jet propulsion.

Although the SR.53 proved to have promising performance during test flights, the requirement for such an aircraft had been overtaken by rapid advances in [[surface-to-air missile]] technology, leading to reconsideration of the aircraft's purpose. In July 1960, the development programme was formally cancelled, by which time a total of 56 test flights had been performed.<ref name="London p. 34"/> A pair of prototype SR.53 aircraft had been completed and used during flight tests. The second prototype was destroyed during one such test flight in June 1958. The first prototype has been preserved to this day.  It rests on public display at the [[Royal Air Force Museum Cosford]].<ref>{{cite web |url=https://www.rafmuseum.org.uk/research/collections/saunders-roe-sr53/ |title=Saunders-Roe SR53 |work=RAF Museum Cosford |access-date=3 June 2019}}</ref>

==Design and development==
===Background===
The [[World War II|Second World War]] had demonstrated the importance of [[strategic bombing]] to modern warfare, and as the emerging [[Cold War]] developed, the development of new and more effective air defences against large waves of hostile [[bomber aircraft]] armed with [[nuclear weapon]]s became a priority for many nations. During the war, [[Nazi Germany]] had extensively developed its own rocket-powered aircraft to augment its interception capabilities, in the final two years of the war, it had been able to deploy aircraft such as the [[Messerschmitt Me 163]] and [[Bachem Ba 349]] which, via rocket propulsion, had been capable of unparalleled rates-of-climb, enabling them to (at least in theory) rapidly sortie to intercept enemy bombers before they reached their targets. As the performance of these aircraft had become increasingly well known to the Allies, RAF experts were eager to explore and understand the underlying technology.<ref name = "wood 53">Wood 1975, p. 53.</ref>

In the aftermath of the war, German rocket technology was studied extensively by various members of the former Allied nations. Britain had quickly opted to commence a programme to develop [[liquid-propellant rocket]]s with the aim of boosting aircraft during the take-off phase, known within the RAF as [[JATO|rocket-assisted take-off gear]] (RATOG), and during the climb-to-altitude phase of flight.<ref name = "wood 53"/> In 1946, work began on a pair of new British-built [[rocket motor]]s, the [[de Havilland Sprite]] with a maximum thrust of {{convert|5000|lbf|kN|order=flip|abbr=on|lk=out}} and the [[Armstrong Siddeley Snarler]] with {{convert|2000|lbf|kN|order=flip|abbr=on}} of thrust; these rocket motors made use of different propellants, the Sprite used a [[high-test peroxide]] (HTP) [[monopropellant]] while the Snarler harnessed a [[methanol]]/water/[[liquid oxygen]] mix. During the early 1950s, both engines proceeded to the flight testing phase; however, some of the demand for their role to provide fighters with increased performance was soon being met by the increasing prevalence of  conventional jet engines being equipped with [[Afterburner|reheat]] instead.<ref name = "wood 53"/>

In May 1951, faced with reports on the increasingly potential capability of, and thus the threat posed by, the growing [[Soviet Union|Soviet]] strategic bomber fleet and that nation's newly developed [[atomic bomb|atomic weapons]], the British [[Air Ministry]] proceeded to draft an [[Operational Requirement]], [[List of Air Ministry specifications#Post 1949 Specifications and Air Staff Operational Requirements.2FTargets .28OR.2FASR.2FAST.29|OR 301]], which sought a rocket-powered interceptor that could attain an altitude of {{convert|60000|ft|order=flip}} in just 2 minutes 30 seconds. Many of the performance requirement laid out by OR 301 was due to the anticipation of rapid increases in performance by the opposing Soviet aircraft; by the early 1960s, it was suspected that these bombers might well be capable of [[supersonic]] speeds of up to [[Mach speed|Mach]] 2 with a potential operational altitude as high as {{convert|80000|ft|order=flip}}.<ref name = "wood 53 54">Wood 1975, pp. 53–54.</ref> Accordingly, a capable defence interceptor that could form part of the nation's measures to counter this threat would need to be capable of similar speeds and an exceptionally high rate of climb in order to reach high altitude bombers in time.<ref name = "wood 54 55">Wood 1975, pp. 54–55.</ref>

The development of the Sprite and the Snarler had led to the possibility of a more powerful rocket engine being developed as the planned powerplant for a viable "point defence" interceptor.<ref name="London p. 29">London 2010, p. 29.</ref> The requirements of O.R. 301 were considered onerous, including a ramp launch and landing on a skid, and with the compliance of the companies which had approached to tender, the amended [[List of Air Ministry Specifications|Specification]] F124T allowed for a mixed powerplant configuration along with the adoption of a conventional undercarriage.<ref name="London p. 29"/> On 21 February 1951, the revised Specification F124T was circulated to half a dozen of Britain's various aircraft manufacturers to solicit their submissions.<ref name = "wood 54">Wood 1975, p. 54.</ref>

===Submissions and selection===
[[Saunders-Roe]] had not been one of the companies who received the Specification; this is likely due to the [[Ministry of Supply]] not considering them to be relevant, as the firm had typically been involved in the production of [[flying boat]]s.<ref name = "wood 54"/> However, Saunders-Roe was in fact interested in the new requirement, having been already independently conducting studies into high-altitude and high-speed flight. [[Maurice Brennan]], the company's chief designer, had already directed members of the design team to study the prospects of rocket-propelled aircraft capable of flying at altitudes of up to {{convert|100000|ft|order=flip}} and had published a report entitled 'Investigation of Problems of Pure Rocket Fighter Aircraft' at the same time that the Ministry had issued Specification F124T.<ref>Dancey, Peter. ''British Aircraft Manufacturers Since 1909'' Fonthill Media, 2014. {{ISBN|1-7815-5229-0}}.</ref><ref name = "wood 54"/> Saunders-Roe approached the Ministry on its failure to follow conventional policy in not dispatching the specification nor an invitation to tender to the firm; as a result, on 24 March 1951, the Ministry asked the company to submit its designs alongside the other competitors.<ref name = "wood 55">Wood 1975, p. 55.</ref>

By the end of April 1951, Saunders-Roe submitted their detailed proposal.<ref name = "wood 55"/> The proposed single-seat aircraft, designated as the ''SR.53'', was capable of very high speeds, being projected as being capable of a top speed of {{convert|2.44|Mach|altitude_ft=60000}} when at an altitude of {{convert|60000|ft|order=flip}}, and a rate of climb of {{convert|52000|ft|order=flip}} per minute around an altitude of {{convert|50000|ft|order=flip}}.<ref name = "wood 55"/> An auxiliary disposable undercarriage could be used for takeoffs, along with [[cordite]]-based booster rockets. In the event of an emergency, the entire cabin would have originally been jettisoned as a means of providing the pilot with a means of escape; due to the work involved in developing this, it was instead replaced by a more standard [[ejection seat]] arrangement.<ref name = "wood 55 56"/> The firm had quickly identified that the original unpowered 'glide home' approach would be dangerous and expensive; they approached the Air Ministry with their concept of a secondary jet engine for the purposes of powering the aircraft's journey home. The Ministry was enthusiastic on this concept; in May 1951, all interested companies were asked to examine this arrangement.<ref name = "wood 55"/>

The SR.53 was a sleek aircraft with a sharply-pointed nose, [[delta wing|delta]]-like wing, and a [[T-tail]].<ref name = "win 223"/> It was powered by a combination of a single [[Armstrong Siddeley Viper]] [[turbojet]] engine and [[de Havilland Spectre]] rocket engine, the exhausts of which were mounted one atop the other on the rear fuselage beneath the tail.<ref name = "win 223">Winchester 2005, p. 223.</ref><ref name = "wood 55 56">Wood 1975, pp. 55–56.</ref> Saunders-Roe had originally proposed to develop their own rocket motor to power the SR.53, having not been initially pleased with the performance of either the Spectre nor the Screamer; however, it was recognised that this would take substantial development work.<ref name = "wood 55 56"/> By October 1952, the basic outline of the aircraft had been finalised, replacing the combined [[flap (aeronautics)|flap]] and [[aileron]]s of earlier proposed with slotted flaps, the Viper engine was relocated upwards and was to be fitted with a straight jet pipe rather than a [[wikt:bifurcation|bifurcated]] one, the tailplane was also moved to a higher position at the top of the fin.<ref name = "wood 56"/>

On 30 October 1952, the company received an Instruction to Proceed from the Ministry for the completion of three prototypes.<ref name = "wood 56"/> On 12 December 1952, further refinement of the concept led to the release of the defined [[List of Air Ministry specifications#Post 1949 Specifications and Air Staff Operational Requirements.2FTargets .28OR.2FASR.2FAST.29|Specification OR 337]].<ref name="London p. 31">London 2010, p. 31.</ref> The changes of the defined specification mainly revolved around armament changes, adopting the [[Blue Jay missile|Blue Jay]] [[infrared]]-guided [[air-to-air missile]], which replaced the originally-envisaged retractable battery of {{convert|2|in|order=flip|adj=on}} rockets.<ref>{{usurped|[https://web.archive.org/web/20030814195436/http://www.spaceuk.org/sr53/RocketInterceptorHistory.htm "The History of the Saunders Roe S.R.53 and S.R.177"]}}</ref><ref name = "wood 56">Wood 1975, p. 56.</ref> During the first four months of 1953, Saunders-Roe had to perform a structural redesign of the SR.53's fuselage, wing, and undercarriage due to a determination by the [[Royal Aircraft Establishment]] (RAE) that the wing required a greater [[Dihedral (aeronautics)#Anhedral|anhedral angle]] than had originally been designed for.<ref name = "wood 56"/>

On 5 May 1953, an advisory design conference was hosted at the Ministry of Supply focusing on the SR.53; three days later, a formal contract for the production of the three prototypes was received.<ref name = "wood 56 57"/> Due to doubts within the RAF and the Ministry over the correct fuel/motor to select for the aircraft in order to meet the Specification, it was decided to issue a modified specification, and later a development contract, to [[Avro|A.V. Roe]], who commenced work on their own rocket-powered interceptor, designated as the [[Avro 720]]. Of the six companies that tendered proposals, two were selected for development contracts: A.V. Roe with their Avro 720 and Saunders-Roe with the SR.53.<ref name="London p. 31"/><ref name = "wood 56 57">Wood 1975, pp. 56–57.</ref>

===Issues and proposals===
Saunders-Roe, recognising that it would need to outdo the competing Avro 720 if the SR.53 was to be likely to survive, upon having been issued with the contract to build the three prototypes, set a schedule that called for a first flight to be conducted in July 1954, along with a projected service introduction date of 1957.<ref name="London p. 30">London 2010, p. 30.</ref><ref name = "wood 57">Wood 1975, p. 57.</ref> However, Wood observes that this was far too ambitious as it did not leave time to address the complexity of the aircraft, nor did it accommodate room for delays in the supply of the separately-produced Spectre engine.<ref name = "wood 57"/> Unresolved issues with elements of the design caused a series of setbacks, including one notable incident in the form of an explosion occurring during ground tests of the Spectre rocket engine. Construction of the first SR.53 prototype took longer than anticipated, in part due to [[de Havilland]] having problems delivering the Spectre engine on time, installing auxiliary equipment was also time-consuming.<ref name = "wood 60 62">Wood 1975, pp. 60–62.</ref> Accordingly, the [[maiden flight]] of the SR.53 began to fall further and further behind schedule.<ref name="London p. 31"/><ref name = "wood 57"/>

The date of the first flight was first set back to March 1955, and then into 1957.<ref name = "wood 60"/> Unique challenges were posed by the HTP fuel, including the development of suitable storage bags and the fuel flow proportioner.<ref name = "wood 60">Wood 1975, p. 60.</ref> In January 1954, the Ministry reduced its order from three SR.53 prototypes to two, which were constructed side by side at Saunders-Roe's [[Cowes]] facility.<ref name = "wood 61"/> Development with the competing Avro 720 proceeded more smoothly; by 1956, its prototype was virtually complete and was viewed as being capable of flying up to a year ahead of the lagging SR.53.<ref name = "wood 60 61">Wood 1975, pp. 60–61.</ref>

By September 1953, the programme to develop these aircraft came under scrutiny due to a need to implement cost cuts; as a result, the contract for the Avro 720 was eventually cancelled. One of the reasons for preferring the SR.53 was although the aircraft was developmentally behind, its use of [[hydrogen peroxide]] as an [[oxidiser]] was viewed as less problematic than the Avro 720's use of [[liquid oxygen]], which posed a fire hazard.<ref name="London p. 30"/> According to Wood, there was a preference for the HTP approach, as used by the SR.53, alongside an unwillingness to continue to support the operation of two different fuel programmes.<ref name = "wood 61">Wood 1975, p. 61.</ref> However, the validity of this reason is undermined somewhat by the fact that Avro had been proposing to switch to using HTP and the Spectre, the same engine that was used by the SR.53.<ref name = "wood 59">Wood 1975, p. 59.</ref> Another factor that had influenced the cancellation was the hesitancy of the RAF to back either project, the service had apparently wanted to wait until after flight evaluations had been conducted before it was to make any determination on its preference.<ref name = "wood 57"/>

During late 1953, Saunders-Roe commenced work upon a derivative design, which was designated the ''[[Saunders-Roe SR.177|SR.177]]''. Brennan considered the lack of an onboard [[radar]] on the SR.53 and the Avro 720 to have been a vital flaw despite it not being a requirement of the specification, leaving the pilot dependent on his own vision and direction being provided by ground-based radar control.<ref name = "wood 57"/> Brennan had also been dissatisfied with the use of the turbojet engine; he believed that a larger jet engine should match the steady supersonic cruising speed of the aircraft, and that the rocket motor should be mainly used for high performance climbs, turns, and rapid acceleration instead. Accordingly, the SR.177 was a much larger and sophisticated aircraft that would provide for more range and overall superior performance to the SR.53.<ref name = "wood 57 58">Wood 1975, pp. 57–58.</ref> It was sized to be able to carry a useful airborne radar, which Brennan had deemed to be essential for interception at the high altitudes at which the new fighter was meant to operate. The new, larger aircraft was also to be developed into separate versions for maritime use by the [[Royal Navy]] and for West Germany as well as for the RAF.<ref name="Jonesp35 38">Jones 1994, pp. 35, 38.</ref> Saunders-Roe worked on both the SR.53 and SR.177, the latter being worked on by a newly formed High Speed Development Section.<ref name = "wood 58">Wood 1975, p. 58.</ref>

==Operational history==
[[File:Saro SR.53.png|thumb|right|Drawing of the first SR.53]]
In October 1951, Saunders-Roe obtained facilities at [[RAF Hurn]], [[Dorset]], to support the site's use as a base for test flights of the SR.53.<ref name = "wood 62">Wood 1975, p. 62.</ref> This measure had been necessitated by a lack of suitable airfields on the [[Isle of Wight]], where the company was based and typically conducted development from. To this end, the firm constructed a HTP storage facility at the Hurn site; specialised radio aids were also installed and initially tested using a specially-modified [[Gloster Meteor]] which had been lent by the Ministry of Supply.<ref name = "wood 62 63">Wood 1975, pp. 62–63.</ref> This setup would ultimately remain unused as flying trials were centered at [[MoD Boscombe Down|RAF Boscombe Down]] instead.<ref name = "wood 63"/>

On 28 June 1956, the completed first prototype, XD145, was dispatched for assembly by the [[Aeroplane and Armament Experimental Establishment]] at RAF Boscombe Down.<ref name = "wood 63">Wood 1975, p. 63.</ref> On 16 January 1957, the first installed ground run of its Spectre engine was performed; on 16 April 1957, this was followed by the first installed ground run of its Viper engine. On 9 May 1957, XD145 conducted the type's first ground taxiing trial.<ref name = "wood 63"/>

On 16 May 1957, [[Squadron Leader]] [[John Stanley Booth|John Booth]] [[Distinguished Flying Cross (United Kingdom)|DFC]] was at the controls of XD145 for the first test flight, following up with the maiden flight of the second prototype XD151, on 6 December 1957.<ref name="London p. 31"/><ref name = "wood 63"/> Test results indicated "...an extremely docile and exceedingly pleasant aircraft to fly, with very well harmonized controls".<ref name="London p. 29"/> Both prototypes flew a total of 56 test flights, with Mach 1.33 speeds being obtained.<ref name="London p. 34">London 2010, p. 34.</ref>

While testing at RAE [[Boscombe Down]], XD151 crashed on 5 June 1958 during an aborted takeoff on its 12th flight. Running off the runway, the aircraft struck a concrete approach light, exploding on impact and killing its pilot, Squadron Leader Booth.<ref>Winchester 2005, p. 222.</ref><ref name = "wood 63"/> The remaining prototype continued to fly with Lt Cdr Peter Lamb taking over the flight test programme.<ref name="London p. 34"/>

==Cancellation==
It was 1957 before the first SR.53 took to the air,<ref name="Flight, 24 May 1957, Mixed Power Intercepter" /> just over a month after the infamous [[1957 Defence White Paper]] had been published outlining the British government's policy to largely abandon piloted aircraft in favour of concentrating on missile development. At the same time, jet engine development had progressed a long way in the six years since the SR.53's initial design. Combined with the fact that improvements in [[radar]] had meant that any incoming bomber threat could be detected much earlier, the need for an aircraft like the SR.53 had disappeared, and the project was cancelled on 29 July 1960, with the third prototype (XD153) never built.<ref name="London p. 34"/>

==Aircraft on display==
The first SR.53 prototype, ''XD145'', is preserved at the [[Royal Air Force Museum Cosford]] near [[Wolverhampton]].<ref>[http://www.rafmuseum.org.uk/cosford/collections/aircraft/saunders-roe-sr53.cfm "Saunders-Roe SR53 ."] {{webarchive|url=https://web.archive.org/web/20100112135423/http://www.rafmuseum.org.uk/cosford/collections/aircraft/saunders-roe-sr53.cfm |date=12 January 2010 }} ''rafmuseum.org.'' Retrieved: 8 August 2010.</ref>

==Operators==
;{{UK}}
*[[Ministry of Supply]]

==Specifications==

{{Aircraft specs
|ref=The British Fighter since 1912<ref name="Mason, Fighter, p401">Mason 1992, p. 401.</ref>
|prime units?=kts
<!--
        General characteristics
-->
|crew=1
|length ft=45
|length in=0
|length note=
|span ft=25
|span in=1.5
|span note=
|height ft=10
|height in=10
|height note=
|wing area sqft=274
|wing area note=
|aspect ratio=<!-- sailplanes -->
|airfoil=RAE 102<ref name="Selig">{{cite web |last1=Lednicer |first1=David |title=The Incomplete Guide to Airfoil Usage |url=https://m-selig.ae.illinois.edu/ads/aircraft.html |website=m-selig.ae.illinois.edu |access-date=16 April 2019}}</ref>
|empty weight lb=7400
|empty weight note=
|gross weight lb=18400
|gross weight note=
|max takeoff weight lb=
|max takeoff weight note=
|fuel capacity={{convert|11000|lb}}, including {{convert|500|lb}} reserved for turbojet engine <ref>{{Cite web|url=https://www.spaceuk.org/sr53/sr53%20data.htm|archive-url=https://archive.today/20181109175148/http://www.spaceuk.org/sr53/sr53%20data.htm|url-status=dead|archive-date=9 November 2018|title=Data|website=spaceuk.org}}</ref>
|more general=
<!--
        Powerplant
-->
|eng1 number=
|eng1 name=[[Armstrong Siddeley ASV.8 Viper 8]]
|eng1 type=[[turbojet]] engine
|eng1 lbf=1640
|eng1 note=

|eng2 number=1
|eng2 name=[[de Havilland Spectre]]
|eng2 type=[[liquid-fuelled rocket]] engine
|eng2 lbf=8000
|eng2 note=
<!--
        Performance
-->
|max speed kts=
|max speed note=
|max speed mach=2.2
|cruise speed kts=
|cruise speed note=
|stall speed kts=
|stall speed note=
|never exceed speed kts=
|never exceed speed note=
|range nmi=
|range note=
|combat range nmi=
|combat range note=
|ferry range nmi=
|ferry range note=
|endurance=7 minutes at full power (jet + rocket)
|ceiling ft=67000
|ceiling note=<ref name="McPhee">{{cite web |last1=McPhee |first1=Andrew |title=unrealaircraft.com - unrealaircraft Resources and Information. |url=http://www.unrealaircraft.com/classics/sr_53_177.php |website=www.unrealaircraft.com |access-date=9 May 2020 |archive-date=2 January 2007 |archive-url=https://web.archive.org/web/20070102155909/http://unrealaircraft.com/classics/sr_53_177.php |url-status=dead }}</ref><br />
*'''Maximum speed:''' Mach 2.2 at {{cvt|52800|ft|0}} (M1.34 achieved)
|g limits=<!-- aerobatic -->
|roll rate=<!-- aerobatic -->
|glide ratio=<!-- sailplanes -->
|climb rate ftmin=52800
|climb rate note=
|time to altitude={{cvt|50000|ft|0}} in 2 minutes 12 seconds
|lift to drag=
|wing loading lb/sqft=67.2
|wing loading note=
|fuel consumption lb/mi=
|thrust/weight=0.52

|more performance=<!--<br />
*'''Take-off run:''' {{cvt||ft|0}}
*'''Take-off distance to {{cvt|50|ft|0}}:''' {{cvt||ft|0}}
*'''Landing run:''' {{cvt||ft|0}}
*'''Landing distance from {{cvt|50|ft|0}}:''' {{cvt||ft|0}}-->
<!--
        Armament
-->
|missiles=2 × [[de Havilland Firestreak]] infra-red guided missiles

|avionics=
}}

== See also ==
{{Portal|Aviation}}
{{aircontent|
|related=
* [[Saunders-Roe SR.177]]
|similar aircraft=
* [[Avro 720]]
* [[Republic XF-91 Thunderceptor]]
* [[SNCASE SE.212 Durandal]]
* [[SNCASO Trident]]
|lists=
* [[List of aircraft of the Royal Air Force]]
}}

==References==

===Notes===
{{Reflist|30em}}

===Bibliography===
*Buttler, Tony and Jean-Louis Delezenne. ''X-Planes of Europe: Secret Research Aircraft from the Golden Age 1946-1974''. Manchester, UK: Hikoki Publications, 2012. {{ISBN|978-1-902-10921-3}}
* Jones, Barry. "Saro's Mixed Power Saga". ''Aeroplane Monthly'', November 1994, Vol 22 No 11 Issue 259. pp.&nbsp;32–39. London:IPC. ISSN 0143-7240.
* London, Pete. "Saunders-Roe's Rocket Fighters." ''Aircraft'', Vol. 43, no. 7, July 2010.
* Mason, Francis K. ''The British Fighter since 1912.'' London: Putnam, 1992. {{ISBN|1-55750-082-7}}.
* Winchester, Jim. "TSR.2." ''Concept Aircraft: Prototypes, X-Planes and Experimental Aircraft''. Kent, UK: Grange Books plc., 2005. {{ISBN|978-1-84013-809-2}}.
* Wood, Derek. ''Project Cancelled: The Disaster of Britain's Abandoned Aircraft Projects''. London, UK: [[Jane's]], 2nd edition, 1986. {{ISBN|0-7106-0441-6}}.
* {{citation |url=http://www.flightglobal.com/flightpdfarchive/view/1957/1957%20-%201200.html |title=Britain's Combat Rocket |page=288 |journal=Flight |date= 30 August 1957 }}
* Buttler, Tony. ''British Secret Projects: Jet Fighters Since 1950.'' Midland Publishing, 2000. {{ISBN|1-8578-0095-8}}.
* Wood, Derek. ''Project Cancelled''. Macdonald and Jane's Publishers, 1975. {{ISBN|0-356-08109-5}}.

== External links ==
{{Commons category}}
*{{usurped|[https://web.archive.org/web/20040827002349/http://www.spaceuk.org/sr53/SR53%20OR.html Text of Operational Requirement 301]}}
*[http://worldatwar.net/chandelle/v1/v1n2/saro177.html Rocket interceptors and S177]
*[https://web.archive.org/web/20070930165232/http://www.britishaircraft.co.uk/aircraftpage.php?ID=242 British Aircraft Directory]
*[http://www.unrealaircraft.com/classics/sr_53_177.php Unreal Aircraft] {{Webarchive|url=https://web.archive.org/web/20070102155909/http://unrealaircraft.com/classics/sr_53_177.php |date=2 January 2007 }}
*{{usurped|[https://web.archive.org/web/20030814195436/http://www.spaceuk.org/sr53/RocketInterceptorHistory.htm Text of official history of SR.53 project]}}

{{Saro aircraft}}

{{DEFAULTSORT:Saunders-Roe Sr.53}}
[[Category:1950s British fighter aircraft]]
[[Category:Mixed-power aircraft]]
[[Category:Rocket-powered aircraft]]
[[Category:Saro aircraft|SR.053]]
[[Category:Cancelled military aircraft projects of the United Kingdom]]
[[Category:Mid-wing aircraft]]
[[Category:Aircraft first flown in 1957]]
[[Category:Aircraft with retractable tricycle landing gear]]