2-stroke Diesels better late than never

For years I have moaned about how crappy piston aircraft engines are. They are prohibitively expensive, yet have antiquated technology and are far less efficient and reliable than modern car engines.

THE MODERN CAR NOW has mature technology engine management systems that prevent knocking and detonation. They burn fuel at the optimal stochiometric ratio – so you don’t have to fool around with the all-important mixture. They are well cooled and so don’t need fussy cowl flaps or have the risk of shock-cooling on the descent. I could go on ….. and on.

I used to fantasise about the ideal personal plane – an A36 Bonanza with a V8 BMW petrol engine on the front. Ever since the Rolls Royce Merlin, we have known that aero engines can be made that will turn at an efficient 5000 rpm and so have much better power to weight ratios and longevity than clunky direct-drive air-cooled ‘Lycocontasaureses’.

Water cooling works well – despite those who claim that a water cooled aero engine makes as much sense as an air cooled submarine engine. A good example is Rotax flat fours, which happily spin at 5000 plus rpm for thousands of hours. 12 years ago there was widespread panic that Avgas would be killed off, as it is the last fuel to still use super-toxic tetra-ethyl lead. And as already noted, Avgas is expensive. Why it should be so expensive remains something of a mystery. There’s very little reason for it to be more expensive than car fuel, as it does not carry road users’ tax or the huge Road Accident Fund insurance premiums. Yet it’s about 25% more expensive than petrol.