Very few South African Flying Records had been ratified by an official body. There are a large number of anecdotal records that are bandied about without any of them have been independently verified. After encouragement from the FAI, SAPFA took on the task of maintaining the documentation relating to speed and altitude records for Class C aircraft.
The record attempts were kicked off at the Overberg Airshow when Dave Stock set the first South African record to be monitored and recorded by SAPFA.
Dave Stock, piloting the Thunder City English Electric Lightning T5 – ZU-BEX, reached 6000m in 70 seconds. The GPS logger placed in the aircraft by SAPFA representatives failed as it was unable to cope with the massive acceleration. The backup manual timing system had to be used.
The Lightning develops 36,000 lbs of thrust whilst burning 500 litres per minute of Jet A1 fuel. The aircraft lifts off the runway at 160 knots and then accelerates to 600 knots (Mach 0.95) before pointing almost straight up to maximise the rate of climb. ZU-BEX was specially prepared for the record attempt and had its external fuel tank removed to reduce weight. In full power with the afterburners aflame the aircraft had only 5 minutes endurance.
Thunder City repeated their assault on the SA Speed and Altitude records at the Ysterplaat Airshow on 3 December 2005. Pilot Dave Stock, Thunder City’s test pilot, was at the controls was accompanied by well known British businessman, John Caudwell. John, a qualified pilot, bought the privilege at a dinner auction for the Caudwell Charitable Trust for £9,000.
The record set was the time to climb to 9 000m record which was completed in 1 minute 43 seconds. This despite the failure of one afterburner.
Ian Pringle, also a Thunder City pilot described the flight profile of the second attempt as follows:
Full power was advanced against the brakes in stages until the wheels started to creep, then full power was selected and the brakes released. The immediate requirement was to check engine rpm and afterburner and, since all parameters were in order, it was GO GO!
On reaching 150 knots the nose was aggressively rotated to the take off attitude. Lift off was achieved at approximately 170 knots, the gear was raised and the aircraft rotated at 2g until the 20 degrees nose up at 200 knots was achieved. The flaps were selected in and passing 250 knots once the gear was up, a rotation forward at 0.2 g was started. Acceleration became the primary focus as the requirement was to go as fast as possible as soon as possible. This was the stage where we caught our breath for the next five seconds or so.
The aircraft was held down until 550 knots was achieved, then a 2 g rotation to 70 degrees nose up was commenced and, once achieving Mach 0.9, the load factor was reduced to 0.4 g, which gives zero pitch rate climb angle was between 70 and 80 degrees nose up.
Passing 12 000 feet, the g was further reduced to 0.3 g with a nose up attitude in excess of 80 degrees in order to maintain Mach 0.9 and the aircraft was rotated to the inverted position. Once inverted, g is maintained at 0.2 g until passing 20 000′. At 20 000′ the aircraft was rotated to erect flight at approximately 60 degrees nose up and a 2 g rotation to the vertical was commenced, the plan being to pass 30 0000′ approaching vertical flight. As 30 000′ was passed the focus was shifted to the recovery where supersonic limits and aircraft handling started to become a concern.
We passed the apex altitude going straight up with speed going straight down and a recovery from the vertical was required. If speed went below 200 KIAS, a compressor stall and after burner flameout was probable. In addition, if the speed was insufficient, the aircraft would perform some sort of oscillatory stall and an auto-rotation and spin were quite possible. The rest was rather simple: recover the aircraft, get the engines back on line and get on the ground with fuel that was probably around the 2000 lb mark.
The next problem was FUEL, FUEL, FUEL or rather, the lack of it – just enough to get on the ground with one overshoot if the chute failed. So it was pull 5g and enter a tight spiral to prevent the aircraft from slipping through the sound barrier with engines at idle. Transfer fuel to the number one fuel tank to ensure that there is sufficient fuel if it becomes necessary to shut down the number two engine. The quickest way down was to keep the speed at Mach 0.88 (avoid Mach 0.93 sonic boom speed), fly for the runway for a low altitude pass, break hard onto downwind to get the speed off, gear and flap down with an approach at 170 knots. Pass over the boundary fence at 155 knots and get the chute out on touchdown. Time to breathe as the entire flight should be less than eight minutes.
Just to confirm what I am sure you already know: one afterburner on the Lightning went out quite early and therefore the time to 9 000 m was about 105 seconds, which is sure to be a South African record – but disappointing as the Overberg flight took just 70 seconds to 6000 m and was a better performance.