Canberra : Early Development

Authors Introduction: This chapter is part of a book that I am attempting to write along with Jagan Pillarisetti,  on the English Electric Canberra in IAF service. We have a blog, please visit there and leave comments by clicking on the "Comment" link near   the title of any blog entry. The author wishes to thank Wg Cdr Vineet Bhalla (Retd) and Wg Cdr Joseph Thomas (Retd) for their help and advice during the preparation of this article.

The English Electric/British Aerospace Canberra first flew on Friday the 13th of May 1949. Yes, that is not a typo - it first flew in 1949 (and they did do the first flight on Friday the Thirteenth)! The Canberra is still operational today with the IAF with 106 Strategic Reconnaissance Squadron (SRS) of the Indian Air Force. This represents a period of 57 years as of 2006! Current plans call for the Indian Air Force to operate their Canberras until May 2007, at which time the type will be 58 years old. To put this longevity in perspective, the World War I Sopwith Camel would need to be operational till 1975 to match this record!

The Indian Air Force (IAF) had by far the largest fleet of “export” Canberras purchasing over a 100 aircraft. Only the RAF and USAF exceeded the IAF in numbers of Canberras operated. The IAF also had the distinction of operating the Canberra “in anger” more often than any other air force. The IAF operates a proliferation of Canberra types, in multiple roles. In this article an attempt is made to describe those types, their technical and operational characteristics and their use in the Indian Air Force.

Early Canberra Development

Design and Development

The prototype English Electric Canberra . (RAF Photo)
The prototype English Electric Canberra . (RAF Photo)

The English Electric Canberra was the brainchild of the brilliant designer W.E.W “Teddy” Petter. Petter was the son of the Managing Director of Westland Aircraft and was initially Chief Designer there. The Westland Wapiti, the first aircraft type operated by the IAF, came from Westland’s stable. Petter designed the Westland Lysander, which 1 Squadron IAF took to war in Burma in 1942 during World War II. Petter seems to have been a favorite designer of the IAF, the IAF operated a representative type for each of the aircraft firms that he was Chief Designer of – the Westland Lysander, the English Electric Canberra and the Folland Gnat! Petter also designed the first and only wholly British Mach 2 fighter, the English Electric Lightning.

The English Electric Company was a locomotive company, and had earned its spurs as a “shadow factory” operator, mass producing Handley Page Hampden and Halifax bombers during World War II. In fact the company’s excellent quality control and prolific output (it produced more Halifax bombers than Handley Page itself) resulted in it being short-listed to build a jet bomber for the RAF in 1944.

English Electric had no design team, so it hired Petter away from Westland. Petter had a reputation for being temperamental and was not getting along with the management at Westland. He had a great opportunity to build a design team from scratch – and he made the most of it! He started work on Air Ministry specification B3/45, which called for high speed, high altitude, unarmed bomber in the tradition of the de Havilland Mosquito.

The aircraft that emerged from the drawing board was designed for a cruising speed of 518 mph at 40000 ft and a service ceiling of 50000 ft – a bar that the Canberra exceeded handsomely. Petter deliberately selected broad chord, low aspect ratio and relatively lightly loaded un-swept wings and decided not to use wing sweep. This gave the Canberra its exceptional handling characteristics at high altitudes and maneuverability at low altitude. The bomber was to be powered by two AJ 65 (Avon) engines, housed in nacelles at about one quarter span and buried in the wings. The horizontal tail was tapered but un-swept. The main undercarriage was inward retracting and mounted immediately inboard of the nacelles. The aircraft had a twin nosewheel. The stressed skin semi-monocoque fuselage accommodated the crew in a pressurized nose section, the design bomb load of 6000 lb and all the fuel. The pilot sat under a one-piece jettisonable canopy and his crew behind him in the fuselage. Every crew member was equipped with an ejection seat. The controls were all manual with spring tabs, being electrically operated for trimming purposes only.

Such was Petter’s foresight in design that the basic configuration of the airplane did not change in 20 years of production. Crew accommodation configuration changes, wing fuel, powered controls, extra wing surface and more powerful engines were all added but the aircraft remained recognizably like the prototype Canberra throughout its life. Even the configuration changes were facilitated by the fact that Petter had designed the Canberra to be of modular construction – with five independent primary structures which could be mixed and matched to meet any role type. These five structures were – front fuselage, centre fuselage, rear fuselage, mainplane non-anti-icing, mainplane anti-icing with integral fuel tanks.

The Early operational marks

The first mark in operational service was the Canberra B Mk 2 – the initial order specifying 5 different marks of the Canberra – tactical bomber, blind bomber, target market bomber, long range PR aircraft and trainer. There were only four B Mk 1s and they were built with solid noses. The radar for the “blind bomber” was not forthcoming so a visual bombing version with a Plexiglas nose with accommodation for three crew members (pilot, navigator and bomb aimer), was built as the B. Mk 2. There was no armament other than the bomb load, and the bomber was to rely on its high speed of 0.8 Mach at 45000 ft to evade any fighters attempting to intercept it. There was a lot of criticism of this change from the radar bombing role to a visual daylight bomber – critics charging that the Canberra was obsolete for that role from the beginning. The operational characteristics of the Canberra however made it adept at performing multiple roles, and that was responsible for its success operationally rather than any single characteristic. The early operational marks – the B Mk 2, P.R. Mk 3 and the T.4 all shared primary characteristics. They were powered by the Rolls Royce Avon Mk 1/RA 3 engine of 6500 lb thrust each. They carried fuel in the fuselage and jettisonable wingtip tanks but did not have any fuel in the wings. Total fuel capacity was of the order of 1,874 gallons with wingtip tanks fitted. The B.2 was a day bomber and could carry 10000 lbs of bombs. The Photo reconnaissance PR.3 had an extended fuselage and could carry up to 7 cameras for both day and night photography and had an extra fuel tank in the fuselage giving it a fuel capacity of 2417 gallons. The T.4, the dual pilot trainer version, will be described with the other IAF specific marks. By the time the Indian Air Force expressed interest in the Canberra, a new “generation” of Canberras had emerged.

Canberras for the Indian Air Force

The Indian Air Force first expressed its interest in the Canberra officially during a visit of the Secretary of Defence in June 1956. A few Indian Air Force pilots had already flown the Canberra by then including the Indian Air Attache to the UK Gp Capt (later Air Chief Marshal and Chief of Air Staff) Moolgavkar. He had flown the Canberra as early as 1954 as part of an evaluation team led by Air Commodore P C Lal. Most ETPS (Empire Test Pilot’s School) courses by then had one or two Indian test pilots under training. Gp Capt Kapil Bhargava, then a Flt Lt and a trainee at ETPS, flew a Canberra T.4 trainer several times as part of his training (see inset).

My brief flirtation with the Canberra

Gp Capt Kapil Bhargava (Retd)

I first flew the Canberra T-4 WJ-867 at the Empire Test Pilots School on 4 Apr 56 with my test pilot instructor Sqn Ldr AE (Al) Marriott. It was in fact a test of the aircraft after some important servicing. That 50 minute dual flight was considered enough to qualify me on the aircraft. My next two flights in the same aircraft (- it was the only Canberra at ETPS) on 30 Apr and 1 May 56 were as pilot in command with Flt Lt AL (Larry) Nelson (Royal Canadian AF) in the co-pilot’s seat. He had similarly done just one flight in the aircraft before these. Our exercise was the calibration of the out side temperature gauge corrected for adiabatic compression temperature rise at different speeds. It was not a very exciting exercise or flight. The next flight as second pilot to Lt Cdr DA (Dave) Cribbs (USN) was a slow cruise climb though only for 1hr 25mts. I next flew the aircraft as pilot in command with Flt Lt HO (Hugh) Field (RAF) on the same exercise of slow cruise climb on July 20 for 1hr 30mts. My final 45mts Canberra T-4 flight at ETPS was on 1 Nov 56 with an intrepid RAF doctor sitting in the co-pilots seat. He obviously had more courage than sense to fly with someone who had only 3hrs 50mts including dual and second pilot sorties. Or, perhaps ignorance was bliss. With the final flight at ETPS I had acquired a grand total of 4hrs 35mts on type. 

Canberra T.4 flown by Gp Capt Bhargava (Steve Bond)
Canberra T.4 flown by Gp Capt Bhargava (Steve Bond)

I had started the ETPS Course as my first posting after getting married and it was our honeymoon. But the course was only ten months long and the Government of India did not foot the bill for the wife’s travel unless the stay was longer than one year. At the initiative of the Indian High Commission, I was attached to Short Brothers in Belfast for test flying duties where the company had to pay nothing for my services. There was not a lot of flying available but the company was manufacturing Canberra B(I) 8s for the RAF. As a recently qualified test pilot, the Ministry of Supply authorized me to flight test and accept any aircraft of any type on its behalf offered for eventual delivery to UK’s armed forces. I also had the authority to ferry it to its destination. This type of blanket clearance actually surprised me though I could not make full use of it. I got only two aircraft (XH 228 and XH 231) to test for a total of five flights adding up to 3hrs 40mts.

Meanwhile, the contract to acquire Canberra aircraft by Indian Air Force included a clause that one in every seven aircraft would be tested and accepted by an Indian test pilot. Wg Cdr Suranjan Das working on the Gnat at Follands was asked by the High Commission to do this test flight for the first such acceptance. He promptly passed the job on to me. This was to be the first flight by any IAF pilot in an IAF Canberra. On 28 May 57, I was to take our Devon from Hendon and fly to Salmesbury to test and accept the aircraft on behalf of IAF. The aircraft was B(I)58 IF-904. Flt Lt Joseph (N) asked me to take him along so that he could become the first navigator to fly in an IAF Canberra. Our departure from Hendon was almost a fiasco. After getting airborne, the undercarriage would not retract. I landed back and asked for technical help. This involved simply putting the master air valve in on position. Sheepishly, I thanked the mechanic for his expertise in solving my problem so quickly. He gave me a withering look, which said it all.

On arrival at Salmesbury, I asked the local chief test pilot for a copy of the production test schedule and a form to fill in the results of the flight. I had done this for two aircraft at Short Brothers and was familiar with the requirements. I also borrowed a copy of the blue (RAF type) Pilots Notes. Little did Joseph know that he had an onerous duty coming up. He got a shock when I asked him to read out the various checks and the starting procedure. I then wanted him to read what it said about taxiing. Finally, after lining up I demanded that he should read out what the notes said about take-off. He was horrified. Immediately after take-off he said to me, “Kapil, the way you are flying the aircraft, any fool could do it”. I at once agreed with him and asked him why ever did he think I wasn’t one.

There were some minor snags to be recorded after flight. The only criticism I had for the company test pilots was their short cut for the elevator trim check. Early Canberra pilots will remember that delivery and in fact all flying of the type had been interrupted due to trim runaway to fully nose down leading to some accidents. The cure was a metal strip about 2cms wide fitted at right angle all along the trailing edge of the elevator. The idea was that at forward C of G, the full nose down trimmer setting should be equal to that for the clean aircraft flying level at 450 knots. The top or bottom edge of the new strip was to be ground down to trail the elevator to the correct angle to meet this requirement. The test pilots had cut the corner by combining this with flying with tip tanks and speed at 425 knots. Even though I did not approve of this, I let it go thinking that if needed we could recheck this back at home. My request to ferry the aircraft to India was turned down flat by the High Commission presumably due to “lack of experience on type”. On return to India I got to do only two flights in Canberra IF-924 while working as a test pilot in HAL. I remember deciding not fly it one day after it had been parked in the sun. It was too hot to handle. A measurement of air temperature in the cockpit showed that it was 52°C.

I was lucky to do two flights on the Canberra F-1189 April 27 and 28 ‘72 to test and clear the HAL developed UHF on it. Hopefully, it or its derivative worked well on the aircraft later in service. My farewell flight on the aircraft was a very pleasant one – Bangalore to Kanpur in the same aircraft on June 22 ‘72 taking 2hrs 40mts. It was the best way to travel – bypassing airlines and trains. With this flight my brief love affair with Canberra (T-4, B(I) 8 and B(I)58) ended with 10mts short of 19hrs on the beautiful aircraft type. One can only wish it had been longer!

Copyright © Gp Capt Kapil Bhargava

English Electric must have felt very confident that they would receive an order; they started work on the IAF Canberras before the order was finally placed in early 1957. The order was for 80 aircraft – and was by far the largest export order placed for the Canberra. The amount was £20 million. Some of this money was offset by the debt that the UK government owed the Indian government for services rendered during WWII and reparations. Even so it seems like the Indian negotiators drove a good bargain – £20 million being approximately $250 million in today’s currency. Seems like a small amount compared to what India is paying for the BAe Hawk today (approximately $1.7 billion for 66 aircraft!).

The orders were for 65 English Electric Canberra B(I)58 aircraft, 8 PR.57 aircraft and 7 T.4 aircraft.

The B(I)58 was equivalent to the RAF’s B(I)8 “interdictor bomber”. The PR.57 was the equivalent of the RAF’s PR.7 photo reconnaissance version. The T.4 was the same mark as the RAF trainer version. It is erroneously reported that the IAF trainers were T.54s but there was no such designation given by either the factory or the IAF. The Indian Air Force never referred to the trainers by any other designation – they were always referred to as T.4s. This was in contrast to the B(I)58 and the PR.57 – those marks were referred to with their full IAF designation.

Being master negotiators, the Indian procurement team had been very wise in prescribing equipment fit – they had included a number of modifications that the RAF pilots wished they had in their equivalent marks! These included a radio altimeter, improved navigation kit and an autopilot.

All the Canberras were to be “new build” aircraft, though 24 were diverted from an RAF order for B(I)8s. One of the these diverted aircraft, a B(I)8 IF-906 (ex-WT388, which is still flying as an Electronic Warfare aircraft with 106 SRS) was modified by Bolton Paul Aircraft to act as the trials installation aircraft for the IAF’s additional equipment. Deliveries of the aircraft started in April 1957.

The IAF marks will be described in detail, but first a small detour into the evolution of the Canberra from the B.2 and PR.3 described above.

The second generation Canberras

In 1951 the RAF issued a new specification B22/48 for a target marker Canberra with improved radar and improved low level performance. English Electric responded with the Canberra B Mk 5. This introduced major changes to the Canberra – the biggest of which was the introduction of the Avon Mk 109 (RA.7) engines. Each of these engines gave 7400 lbs of thrust which was 900 lb more on each side than the Avon RA.3 fitted on the B. Mk 2, PR. Mk 3 and the T.4. Another major structural change was the addition of integral wing tanks which gave a total of 900 gallons additional fuel. Dunlop “Maxaret” anti-skid braking units were introduced. The changes increased range to 3,400 miles and the maximum speed increased by 10 mph. The Avon RA.7 had anti-icing protection and was more resistant to compressor stalls and surging. The radar desired for the Canberra B Mk 5 did not materialize and this resulted in the visual bombing Canberra B MK 6 being produced instead. The Canberra B Mk 6 was a B MK 2 bomber incorporating the improvements introduced by the B Mk 5. The B Mk 6 was essentially what all the IAF Canberra marks (except the T.4) were based on.