Saunders-Roe SR.53

infobox Aircraft
name = SR.53
type = Interceptor
manufacturer = Saunders-Roe



caption =
designer =
first flight = 16 May 1957
introduced =
retired =
status = Experimental
primary user = United Kingdom
more users =
produced =
number built =2
unit cost =
developed from =
variants with their own articles = Saunders-Roe SR.177

The Saunders-Roe SR.53 was a prototype interceptor aircraft of mixed jet and rocket propulsion developed for the Royal Air Force in the early 1950s. Although its performance was promising, the need for such an aircraft was soon overtaken by surface-to-air missile development, and the project was cancelled after forty-two test flights.

Development

The Second World War demonstrated the importance of strategic bombing to modern warfare, and as the Cold War developed, devising effective air defence against large waves of enemy bomber aircraft became a priority for many nations. Nazi Germany had looked to rocket-powered aircraft to fill this niche, with machines like the Messerschmitt Me 163 and Bachem Ba 349, which were capable of unparalleled rates-of-climb, enabling them to (at least in theory) rise to meet and intercept enemy bombers before they reached their targets. German rocket technology was studied extensively by the Allies in the aftermath of the war, and in light of the threat of the growing Soviet strategic bomber fleet and that nation's newly-developed atomic weapons, the UK's Air Ministry drafted an Operational Requirement O.R. 301 in May 1951 for a rocket-powered interceptor that could reach an altitude of 60,000 ft (18,300 m) in just 2 minutes 30 seconds. This was circulated to the nation's aircraft manufacturers the following February.

Of the seven companies that tendered designs, two were selected for development contracts, A.V. Roe with their Avro 720 and Saunders-Roe with their SR.53. The SR-53 itself was a sleek aircraft with a sharply pointed nose, delta-like wing, and a T-tail. The jet and rocket exhausts were mounted one atop the other in the tail.

By September 1953 the programme to develop these aircraft came under scrutiny due to cost cuts, and the Avro 720 was abandoned, although it seemed almost ready to fly at this point. 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. Nevertheless, a series of setbacks, including an explosion during ground tests of the engine, saw the aircraft's first flight fall further and further behind schedule. At the same time, Saunders-Roe began work on a derivative design, the SR.177, adapting the SR.53 design for maritime use by the Royal Navy and the German Navy.

It was 1957 before the aircraft was to take to the air, 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, unsurprisingly, the project was cancelled. The first SR.53 prototype, "XD145", is preserved at the RAF Museum at Cosford near Wolverhampton. The other, "XD151", crashed on 5 June 1958 during an abandoned take-off whilst testing at RAE Boscombe Down, killing its pilot, Squadron Leader John S. Booth DFC. [ [http://www.testflyingmemorial.com/1946-70.htm Test Flying Memorial website] ]

Operators

;UK
*Ministry of SupplyFact|date=April 2008

pecifications

aircraft specifications
plane or copter?=plane
jet or prop?=both
ref= [http://www.britishaircraft.co.uk/aircraftpage.php?ID=242 British Aircraft Directory] ]
crew=One, pilot
capacity=
payload main=
payload alt=
length main= 45 ft
length alt=13.72 m
span main=25 ft 1 in
span alt=7.65 m
height main=10 ft 10 in
height alt=3.30 m
area main= 274 ft²
area alt= 25.45 m²
airfoil=
empty weight main=6,635 lb
empty weight alt= 3,016 kg
loaded weight main=18,361 lb
loaded weight alt= 8,346 kg
useful load main=
useful load alt=
max takeoff weight main=
max takeoff weight alt=
more general=
engine (jet)=Armstrong Siddeley Viper 8
type of jet=turbojet
number of jets=1
thrust main= 1,640 lb
thrust alt= 7.3 kN
thrust original=
afterburning thrust main=
afterburning thrust alt=
engine (prop)=de Havilland Spectre
type of prop=rocket
number of props=1
power main= 8,000 lbf
power alt=35.7 kN
power original=
max speed main= Mach 2.35
max speed alt= 1,334 mph, 2,135 km/h
cruise speed main=
cruise speed alt=
stall speed main=
stall speed alt=
never exceed speed main=
never exceed speed alt=
range main=
range alt=
ceiling main= 67,000 ft
ceiling alt= 20,420 m
climb rate main= 24,000 ft/min
climb rate alt= 7,317 m/min
climb rate more=: 2 min 12 sec from brakes to 50,000 ft
loading main= 67 lb/ft²
loading alt=328 kg/m²
thrust/weight=1:2
power/mass main=
power/mass alt=
more performance=
* Endurance at full power: 7 minutes
missiles=
* 2 × de Havilland Firestreak infra-red guided missiles
avionics=

ee also

aircontent
related=
*SR.177
similar aircraft=
*Avro 720
*Sud Ouest S.O.9000
*XF-91 Thunderceptor
sequence=
lists=
* List of aircraft of the RAF

References

External links

* [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]
* [http://www.britishaircraft.co.uk/aircraftpage.php?ID=242 British Aircraft Directory]
* [http://www.unrealaircraft.com/classics/sr_53_177.php Unreal Aircraft]
* [http://www.spaceuk.org/sr53/RocketInterceptorHistory.htm Text of official history of SR.53 project]