I walked out of the performance exam 23 minutes after I walked in. It was somewhat to the surprise of the invigilators and the result of the most incredible bit of luck. I needed a pass in four days from scratch to get my first job and 3 quid for a fast track marking saw me on Channel Airways' DC3 training by Thursday. ARB's pre-passed on a mass of aircraft thanks to "Pop Speller's notes."
Despite seemingly having a natural ability with graphs, I had an instinctive belief that Performance A was a total nonsense. While on an extended vacation in Texas I stayed in aviation pioneer Col Carl Crane's* cabin in the Texas hills. He invited me to test fly his blind landing prototype on numerous occasions. While looking through his work I noticed a patent he held which advised pilots of the distance remaining/passed of the runway during T/O or Landing. I realised that his notion of selling receivers worldwide was unnecessary, as most aircraft had 75MHz receivers which fed audio to the pilots. I further realised that the tone could be replaced with not only the audio of distance readout, but a code which could be fed into a performance computer. I came back to the UK with an agreement that he would have the American market and I would have the rest of the world.
I sent extensive text and plans to the ?? government development board ?? (something like that.) They typically put in 50% on such projects. After some weeks I was knocked back to be told that they were already funding a project that was too similar to allow my application - which they were otherwise intrigued by. Quite a blow.
Co-location of DME's would have seen a quick end to multi lobe 75MHz transmitters. I smile now at my naïveté.
It seemed there was a BAC 1-11 charging up and down a runway somewhere using Doppler to measure the progress. It seems it worked . . . until it didn't, losing all reference to the progress. IIRC, their readout was a second needle on the ASI. Rather more basic than my making use of a multi-functional radar screen. I'd gained Marconi's interest in that at a science display in Alexandra Palace. Not many people were interested in TV screens in aircraft back then but there was a lot of redundancy in the radar unit's capabilities - not least of all a continuous wind velocity vector during approach.
The BAC 1-11 project devoured funds and was wound up.
Every so often over many years I would experience bewildering issues with performance. One vivid memory was being with my Fleet Manager, so it must have been a windless and fine day. We left Spit on what I deemed to be a marginal runway but the concrete slabs were so misaligned/heaved, that the crashing vertical input was thunderous. I pushed the power to the stops about half way along, and called V1 as we staggered over the rocks. The concept of energy-sucking vertical 'noise' being introduced was not in any graph I remember. Nothing was done. Nothing was ever said.
Forty years later I'm still reading of fence-scraping take-offs. It's not just my misguided gut feeling is it? So many V1 calculations have to be nothing short of ludicrous.
*There's a lot about Col Carl Crane on t'net. He fell out of the clouds in a biplane with a senator's son on board. He devoted much of his life after that teaching people they can't fly in cloud without instruments. He was a guest speaker at Randolph Advanced Instrument flying school in Texas where his talks left the young pilots spellbound.