The Mustang and the Speed of Sound

 

By Bill Wilkinson

 

My stay in Dunedin was the most exciting in my flying life. The crowning moment came on the 1st of May 1954 when I went solo in the Mustang. This was a very inspiring aeroplane to fly. Every time I pushed the throttle lever forward I would say to myself," This is too good to be true." For the next few months I would do one or two flights a week and gradually got the feel of flying New Zealand's front line aircraft.

 

On the 1st of August I was detailed to get some high altitude experience. The take-off and climb were normal. The second stage of the supercharger kicked in at 12,000 feet and I continued the climb keeping a careful eye on the oxygen "eye" on the instrument panel. I made sure that it was blinking at me. Pilots and aircraft had been lost through failure of the oxygen system.

 

My orders were to fly up to the maximum ceiling around 37,000 feet. When I reached this height it was obvious that any further gain was out of the question. The thin air was barely holding the aircraft up. It felt very much as if I was balancing on top of a steeple. The controls were sloppy, not sharp and responsive as in lower altitudes. The outside air temperature was -50°C.

 

I was admiring the view, wondering why I had not brought my camera with me, when the radio came to life, " Red One, we are taking a tea break in a few minutes, are you coming down or will I call you in an hours time?" the Controller asked.

 

"I will be right down," I replied.

 

I glanced at the Air Speed Indicator and saw a reading of about 120 knots. I knew that the readings would be distorted due to the high altitude and low temperatures but I did not know by how much.

 

I pushed the stick forwards and started to dive. There was stiffening in the controls and I looked at the ASI. It read 320 knots.

 

The dive became steeper and the control felt as though it was set in concrete. I tried very hard to pull out of the dive.

 

Nothing happened. I wound the trim back. Still no response.

 

I knew then that I had lost control and that, in less than a minute, I would be part of a very large hole in the ground. The altimeter was unwinding rapidly.

 

I had heard that people who are about to die have their lifetime flash before their eyes. This I disbelieved until now.

 

Almost every event of my life rushed before me. It was as if my brain was looking for a way out of my predicament.

 

My thoughts suddenly locked into an overheard conversation in the Mess at Wigram a few months previously.

 

As usual, after a day's flying we stopped off for a few drinks before dinner. We gravitated into groups clutching our beers.

 

During a break in the conversation I overheard some one behind me discussing flying the Mustang at the Critical Mach Number. He said," Whatever you do, don't touch the trims, throttle back and hang on. At around 5,000 feet, when the air becomes denser, you will regain control." I never saw the speaker.

 

I wound the trim back to where I thought it should be. There was now a very loud noise surrounding me. I glanced at the RPM it was reading 3,700, way over the red line.

 

Just to complicate matters, I had a runaway prop.

 

I hung on and the altimeter continued to unwind. The throttle was hard back.

 

At 5,000 feet the feeling in the controls began to return. I pulled the stick back as hard as I could.

 

I flew over the hangar at less than a thousand feet with a hiss and a roar.

 

The squadron were starting their tea break when the hangar roof went up and then crashed down.

 

The comments that went round were of the nature, "That B*#*# Wilkinson is a noisy sod."

 

What they did not know was that I had been scared witless. It took a half hour sitting in the sun before I became coherent again.

 

My next flight was to take AC2 Keeble up to Oterehua in a Harvard to see the ice-skating. He had never flown before. It was the ideal therapy for me.

 

Later, we worked out that high altitudes and low temperatures ASIs gave very erroneous readings. The 320 indicated was nearer to 600 mph and was up to the Critical Mach Number. At that speed a shock wave forms on all of the aerofoil surfaces and control is lost*.

 

Seven months later Patrick Vowles, one of my friends, was killed in similar circumstances near Lincoln College.

This little episode did not spoil my love for the P51D. I continued to fly with the squadron until March 1955 when these aircraft were declared obsolete.

 

My last flight in a mustang was in 1969 in San Francisco. It was owned by Dr Arthur Duff, an old pal from student.

 

*See page 251 Flight Without Formula, Third edition, by A.C. Kermode