raven

When I was young, Limbach, Germany, took air-cooled VW car engines and converted loads of them to safer yet more powerful aircraft engines mainly due to their initial light weight and opposed design. Many were produced although a batch of dual ignition magneto's caused a bunch of engine outs including our plane, a stol Protech. I believe they were popular for some time. Subaru engines did not prove to have the reliability from what I saw back then. Going forward, the moment battery technology can 'halve' the weight of lithium batteries, electric motors will take off like mad I believe as the compact size, massive torque, cooling, noise, no flammable liquids etc etc make them far superior. In motorcycles, last year, saw some of the first weight-matching, distance-matching battery/elec bikes. Quick release battery swap cassettes for light aircraft would obviouly be necessary at many locations.

Agree with some of your physics but generally disagree...In the airforce, our twin engine aircraft saved lives with many engines having to be shut down over the years as they were powered correctly...experimental aircraft are often not set up with enough power per engine and i agree, people not set up their fuel systems and other correctly

Interesting about twins ruling...what is their reasoning?

Yamaha's inline 4 cylinder options like the 100-150hp may be considerable. If a person is designing a light, twin engine machine, consider the ktm 890 twin engine from their adventure bike ...ULTRALIGHT per kw/hp, designed for constant speeds, good torque, bulletproof, efi, altitude compensation, suitable sump design, its radiors go straight across to the airframe, throw on a belt and pulleys and the sound is magnificient. and yes, 1 on each wing. Serious

As an aircraft technician and after years around kit aircraft, I say you are right on the money skippydiesel...these yamaha outboards, particularly the new 2024 model 350hp V6, could be the ultimate high speed kit aircraft engine for many reasons... * these engines are designed for incredible durability and years of service without deep rebuilds * the core engine's power to weight is impressive * the torque at low rpm is very suitable for a modern, swept, carbon prop * considering its great torque curve, there would be no need to rev it above 4500rpm often * would work great with variable pitch prop * cooling system can be relatively easily converted to a aircraft radiator * lots of gearbox choices out there for high speed sport aircraft * need to look into the sump oil pick-up point/design more but how aerobatic are you going?...outside loops may be a drama. * altitude fueling compensation considerations also but there are options and lots more good reasons but above all, safety, from the inbuilt durability so boaties don't get stuck way out to sea Just my opinion of course, but I am seriously thinking of converting the 350 or 450 V8 for a bigger aircraft application....mmmm a scaled mustang with the 5.6 litter 450hp Yamaha V8...sounds sexy right? Safe flights boys!!