The
Herald also used water-methanol when extra power was needed from the two Darts. The tank held up to 80 kg, and we seemed to carry it around quite often in case it was needed? That's equivalent weight to an adult, which seems a bit wasteful.
In hot summer weather (well, hot by UK standards
) we could actually be WAT-limited at sea-level. So with a full pax load out of Southampton - even just to get to Jersey or Guernsey - we had to do a flapless, water-meth take-off.** To an outside observer, the Dart seemed to make a sort of flapping noise with water-meth.
** [only for those not familiar with Performance]
To improve the single-engine initial climb gradient. The runway at SOU was just long enough to permit the higher take-off speed involved.
Digital Pocket Calculators
Prior to smartphones, the handiest one I ever had was solar powered, but in practice also worked indoors with normal room lighting. Like JW411, I've always been paranoid and bloody-minded about retaining my mental-arithmetic skills, even if it only involves achieving an approximate result. The latter is invaluable for checking that, in the 8-figure result from the calculator, the decimal point is in the right place...
We early users were sometimes sceptical on reliability, and I wonder if anyone else used this test:
0.9 X 12345679 = 11111111.
Going back to about 1970, before such things were cheaply available, the Dart Herald's fuel-quantity gauges were calibrated in imperial gallons, whereas the flow-meters and fuel-used counters were in kilograms. At the end of each sector, prior to refuelling, we would log the arrival fuel in both indicated and calculated amounts. (The "calculated" would be the recorded departure fuel minus the burn-off recorded by the two flowmeters.)
As every schoolboy knows, the SG of kerosene is about 0.8, so an imperial gallon weighs about 8 lb or 3.6 kg. We therefore needed to divide the burn-off in kgs by 3.6. The trick is to divide it first by 4. Then you first add a tenth of that to the result, then an extra hundredth, and (if you really want to!) an extra thousandth.
Who needs calculators?
