I threw this topic in A2A forums, but decided to take it here also, as we may get a little different perspective here. So, my question, or pondering is this (direct quote of my own post from A2A-forums):

 

After reading tons of stuff of old piston engined planes of the history (and flown in simulators of course!), mostly from the WW2 era, I've sometimes wondered, how much better piston engined planes we would be manufacturing today, if that would be powerplant of the choice even during modern times.

 

There are of course many factors considering the developement of the aircraft, both civilian and military. Powerplant is only one of them, but light alloys, electronics and computers (with aircraft design and as part of the aircraft avionics) have changed the flight remarkably since the epitome of best piston engined planes we know them and as some of them A2A represents for us in FSX.

 

There has been technolgical advancements here and there during the decades, some are originating purely from aircraft industry and some, perhaps most are from other fields invented during the decades since the late 40's or early 50's. Still today, for example in Reno Air Races unlimited class' best is full of modified WW2 fighters, not fully custom built piston engined planes. Is it just because it is easier and cheaper to build upon existing airframe along the rules and along the requirements to succeed in the race and not in generally? Perhaps? Probably?

 

This is complicated question IMO, because a lot has changed in not just engines, but also materials, aerodynamics and avionics. We know only one thing: if we would have only piston engined propeller driven aircraft today, sound barrier would remain as a myth or purely a theoretical question, not a tested one.

 

So, this is purely speculative thread where you can approach the subject from the perspective you choose. Whether with modern avionics or without them, with modern weapons systems or without them. Only remaining requirement and constant is a piston engine as a power plant.

 

Where would we be now and how good planes they made back then, is the question?

The big thing is that it costs a whole boatload of money to certify all these things to make pistons more efficient and powerful. The two that I like the most is the electronic ignition and the computers that control fuel and propeller pitch angle to be the most efficient. Here is a little video on the electronic ignition and how this simple change makes the aircraft more efficient. The aircraft would be really efficient if both mags could be replaced.

 

"This is complicated question IMO, because a lot has changed in not just engines, but also materials, aerodynamics and avionics. We know only one thing: if we would have only piston engined propeller driven aircraft today, sound barrier would remain as a myth or purely a theoretical question, not a tested one."

 

One problem is that props can only rotate so fast before the blade tips hit the sound barrier, which makes them very inefficient.

There are ways around the problem of prop tips going supersonic. More blades, bigger props turning slower, tip geometry, etc.

 

I think on the transport side we'd have planes that looked a lot like the piston behemoths of the 1950s. They pretty much reached the limits of what you can do with reciprocating engines on the turbo-compound radial monsters they hung on those things. Those engines just got so heavy and complex ( = expensive) that it only made sense to replace them with turbines.

 

But the move away from pistons at the top end of powerplant development has left us with piston engines in the GA fleet that have changed very little in the last 60 years. Like Chris said, there are some cool new developments, but in small airplanes the payoffs just aren't big enough to overcome the regulatory burdens. It's too bad, in a lot of ways, because pistons have some advantages over turbines in terms of overall efficiency in some low-speed, low-altitude applications, which is why the Voyager was piston-powered. If some good, large-scale piston alternatives were available, they might still make sense for regional airliners.

 

Dave