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Arrow Pilots:Jan Zurakowski

Jan Zurakowski:
Test Flying the Arrow. pg3

And Other High Speed Jet Aircraft.

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TEST FLYING THE ARROW

and other high speed jet aircraft.
Jan Zurakowski

Arrow Rollout
A large crowd attends the roll-out cerimony. Oct 4, 1957.


continued from page 2,

     Second example. A heating and air conditioning system was designed for the CF-100. A specification was raised for the manufacture of a unit delivering a specified amount of air per minute at a specified temperature and engine speed. The aircraft was instrumented to check this system and flight tests were carried out according to the design office programme. Their technical observer was very happy: the system delivered everything as designed, and in spite of my objections the results were considered as satisfactory.

     From my own experience I was sure that the system was poor. The cockpit heating and air conditioning system was designed for maximum cruising power (very close to maximum power) at the highest altitude, but at the most economical cruising speed engine power was so low that the temperature in the cockpit was around the freezing point.

     I managed to squeeze in one more test. Before the flight, however, I secretly put on two sweaters and two pairs of thermal underwear, without saying anything to my satisfied observer. After a one-hour cruise, my observer was so stiff from cold that upon landing he had to be pulled out of the cockpit. After a half-hour defrosting he agreed that the system required considerable improvement.

     Third example. One of my last flights at Gloster was for canopy jettison on the two-seater Meteor Mk. 7. During jettison a canopy, weighing about 160 lbs and more than six feet long, had to be lifted by the airstream, pivoting at the rear hinge and, after reaching about 30deg, be disengaged automatically to then pass clear over the tailplane. The test was recorded from another aircraft by cine camera.

     The CF-100 had a similar size and shape canopy, but to my surprise the hinge pin at the back of the canopy was a bolt of 1/8" or 3/16" thickness, whilst on the Meteor it was half an inch. Because the cabin of the CF-100 was pressurized I expected loads to be much higher, so I suspected that something was wrong. I was assured that ground tests were satisfactory, but when a test report could not be produced I requested a test.

     More than twenty ground jettison tests were carried out, but results were none too satisfactory. Somebody arrived at the conclusion that ground simulations of the air loads are not representative enough, so the only answer was to test the system in flight.

     I was sure that if something doesn't work on the ground it was unlikely to work in the air, but we started jettison tests. I jettisoned more than ten canopies over Camp Borden. The system was modified step by step, but results were not satisfactory and it was considered too risky to try at higher speeds.

      One day I was sent to Los Angeles for a three-day course about new missiles. I was surprised that the course was about storing and maintenance of Falcon rockets. On my return to Malton I was informed that in the meantime a meeting had been held between representatives of the design office and the air force. Canopy jettison was presented as satisfactory; the air force was convinced and agreement was reached that no more work was needed. I had lost a battle. My own opinion was that Canada, being a rich country, could afford a higher safety for flying crew.

     Maybe these battles were useful. On the new design, the Arrow, crew emergency escape system was developed to a very high standard for a much wider range of speed. For cockpit air conditioning, a ground testing rig was built to develop and prove the system and I had no serious problems in flight.

     I would like to stress here that although I am making critical remarks about some design features, or some persons, I was fully aware of the problems facing the design office and as a whole I was very impressed by the work done.

     An experimental test pilot is not a popular person in the design department. Most of the designers are highly optimistic about their own design, and it is not a pleasant task after a flight to explain or to prove that optimism is just not justified. Quite often the reaction of the designer is to say that everything is excellent, that the pilots are simply too fussy, that they want to have their own way, or that they have the prima donna complex.

 

But if everything was so excellent, why then, for example, did such a successful aircraft as the Meteor require more than 1500 airframe modifications during its development and more than 500 engine modifications, of which about 30% had to be developed and proven in flight?

     Maybe because of the continuous effort to improve the Meteor and its engines, the speed and ceiling of the aircraft was increased by more than 20%, range and armament doubled, with continuous improvement of reliability. Four Gloster test pilots lost their lives on this work.

     In the production department, the experimental pilot again is not a popular person. Nearly every production manager would like to set up his assembly line, establish a schedule, and then run the production smoothly without any interruption. He is furious when every week five or more modifications have to be incorporated somewhere on the assembly line, and worst of all when the aircraft is ready for acceptance flight.

     Who is to blame? - Of course, the test pilot. Why didn't he discover trouble before? Is modification really necessary? Why did it take so long to prove modifications in flight? - And so on.

     The department of technical sales and public relations was usually the only one which was not always cross with test pilots. But when priority was given to an urgent development flight and not to a demonstration of an aircraft for some important or not so important guests, relations were strained quickly.

    In September 1952 the A. V. Roe Company purchased a jet engine plant at Malton from the government, later known as Orenda Engines. I would like to mention that, due to their high reliability and serviceability, the Orenda engines in the CF-100 and the Sabre were a great asset in speeding up the development flying. In 1956, if I remember correctly, the RCAF sent four CF-100's to the U. S. A. for comparative armament trials at Eglin Air Force Base. The tests were carried out by U. S. Air Force crews. During our visit there, one of the American officers said to me: "Your armament is the best we have ever tested, but actually I want to congratulate you Canadians on the design of your engines: simple in operation and reliable."

     Nineteen fifty-four was an unlucky year for me. The Air Force requested an investigation into heavier armament for the CF-100, and a proposal was put forward to install 50 rockets in the fuselage in a special pack which would be lowered for a fraction of a second to fire the rockets, followed by immediate retraction. Initial tests indicated that lowering of the square pack produced very strong vibrations, buffetting of the aircraft, and strong change of trim.

     The Engineering Division insisted on measurement of stability at all speed ranges with the pack up and down, so that an automatic correction system to the controls could be designed to eliminate any change of trim occurring at the critical firing moment. During one of these tests, an unexplainable explosion occurred at 5000 feet in the rear of the aircraft, which locked the flying controls in a position that forced the aircraft to turn and dive. I jettisoned the rocket pack and prepared to abandon the aircraft. After jettisoning the canopy I heard another explosion and assumed that my observer John Hiebert had ejected. Then I used my own seat ejection. When my parachute opened I realized that my right ankle was probably fractured. I landed on my left foot in a hard field near Ajax.

     In the hospital I learned that the second explosion was not the ejection of my observer, but rather another explosion which probably damaged his ejection mechanism or incapacitated him. He was killed in the crash.

     My impression was that the cause of the accident was probably ignition by an electric spark of fuel spilled in the rear fuselage from fuel lines fractured by excessive vibration of the aircraft with the rocket pack down.

     The daily press stories that I was trying to save populated areas by directing the aircraft to open fields have no relation to the facts. After the first explosion I was unable to move the controls even a fraction of an inch.

     My second accident in 1954 was a bit strange. After a routine experimental flight in the CF-100

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