The A2A Simulations Community

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?

I apologize, however your wording is somewhat vague right around the actual question itself. However my interpretation says that your question was: "What level of advancement would today's aircraft be at, had modern piston engine technology existed at the time WWII aircraft were designed."

My answer is, not too different. Indeed we have TSIO-550-C flat-six engines with GAMI injectors and electronic ignition, but what does that give us? Lets take a look at arguably the greatest airplane ever built, the Douglas DC-3; she first flew over 76 years ago, 400 still remain in service worldwide, and no other airplane has come to match what it does. This is a plane powered by two Pratt & Whitney R-1830 radial engines (first run in 1932, 80 years ago), it was designed without computers, calculators, just hand-drawn math. It can deliver cargo cheaper than any other plane, flies as fast as any light twin (Beech Baron or Cessna 310), and can carr 25 people. It can land on snow, water, gravel, tarmac, dirt, grass, what have you. Modern engine technology wouldn't have done any good for the DC-3; the Bastler BT-67 turboprops have been made, but the radials are still better. (apologies, its a BT-67, not -17; edited to fix)

Let's look at the de Havilland Beaver, powered by a Pratt & Whitney R-985 (first run in 1929, 83 years ago), it was first flown on August 16, 1947. The Beaver can land shorter than most any production plane, can haul six people, or 2,100 lbs, land on snow, water, or anything in the bush. Although being in service long enough to be on medicare, no plane has matched the Beaver, and the old radial engine is still the best engine for the beaver, although the PT-6 sees limited application. Nothing today would have made the Beaver any better, if it could have, somebody would be out to make a fortune.

Modern technology indeed helps make a single go fast with its gear down, and the autopilot is one of the greatest tools pilots have, but is it really better? We put new avionics in the old airplanes, and voila! We have the best thing money can buy. Our technology makes big airliners more effecient, and for new planes being built for city-slicker general aviation, sure, its great. But when it boils down to being better, a Cessna Corvalis TT doesn't compete with a 50 year-old Baron, except for the highest price.

_________________
© 2011 Peter J. Carlson, All Rights Reserved
"O! for a horse with wings!" -William Shakespeare

No need to apologize. I mostly meant, for example, how much better P-51D NAA would make today, if they would be bound just to piston engine. Or they would have every knowledge then we have today, but perhaps without the avionics or weapons systems: just aerodynamics and materials. Would the result be in the style of Reno Air Race modified planes or something else?

I left the subject vague intentionally and based the question solely on the powerplant: if we wouldn't have jet engine, but pistons, where would we be now?

Edit: And of course piston engines are still good in many GA applications. What I meant was if pistons would be the best powerplant option we have even today to all applications, to military and tubes hauling passengers around the world.

Well a P-51 Mustang with a turbine wouldn't be as good a performer as a Mustang with a V-1650. The turbine engines spool up and down, and aren't snappy like a good ol' piston engine. Lockheed had proposals for a jet-powered fighter around 1939, however the USAAC didn't see any need for a jet fighter. They weren't necissarily 'bound' by the piston engine; yes, jets were in their infancy, but it wasn't the only option.

Piston engines were great for airliners before the baby boomers because kids, because air travel was reserved for the classy, sophisticated, and well to-do people, rather than the common means of transportation. Back then, train, bus and even oceanliner were the commoner's preffered mode of long-distance travel, and planes didn't need to haul as many passengers. However once the baby-boomers had grown up, their parents, the veterans, wanted to show them the world that they had the privelge of seeing during the war. Before WWII, most people stuck to their own country, or region (ie. Europe), and the far reaches of the world were for the politicians, [corporate] businessmen, politicians, and the aristocracy (like the peerage of Great Britain, you know, Downton Abbey sort of thing). But once the American and British soliders (for the most part) had seen the far reaches of the world, they wanted to go back, and show their families. Soon, demand for air travel rose, as people couldn't take a train or bus to China or France...although air travel was still not the common mode of transport. The jet came along as both technology and demand matured, and its ability to fly higher and faster meant that effeciency rose, turn-around time allowed more revenue service, and the jet engine was much more reliable.

If we hadn't gotten the jet engine, we'd have followed the course of the Lockheed Constitution, the Convair XC-99, and the Bristol Brabazon. Those were the massive propliner/cargo transports, of which two, one, and one were made, respectively. We would have seen the advance of large radial engines, improvement in alloys, ignition, injection, and propeller technology, and I wouldn't be surprised if 10,000hp radials would be in service today, had the jet not existed. Nor would air travel have become the main mode of transport, and we would see an airline industry that still catered to the select few, that wasn't a charity like today, and a world with more trains, buses, and oceanliners in service.

_________________
© 2011 Peter J. Carlson, All Rights Reserved
"O! for a horse with wings!" -William Shakespeare

Wait, what kind of turbine? The Piper Enforcer, which was developed from the Cavalier Mustang II was a very good airframe. The only reason it didn't go anywhere was because the USAF decided it didn't "need" the airplane, not because it didn't work. With a geared turboprop, the engine response is actually faster than a piston as there is no change in RPM, only prop pitch for changes in power. This actually makes the aircraft better for such work. That's why the OV-10 was such a well respected FAC and light attack aircraft.

Additionally, with FADEC, spool times on small turbine engines has been greatly reduced. Watch an Eclipse 500 or Citation Mustang takeoff, the little Williams FJ44's spool up almost instantly and stabilize accurately well before you can throttle up and stabilize a Merlin. They also don't suffer from "power creep" as the aircraft accelerates because of the FADEC, something you have to be careful of with any high horsepower piston.

As for Reno - it's because by modifiying an existing design they can get certification more easily and nothing more. The aircraft internally are nowhere near stock and the engines they run are very specifically built beasts designed to be massively overboosted versus their original design. Their performance on the course would never be able to directly translate into air combat environment.

Also, Peter, I admire your enthusiasm, but it doesn't help your case when you can't get simple information right. The Basler conversion is the BT-67, not the BT-17. Additionally, it IS a markedly better performer for a lower cost than the DC-3. Not least of which is that they extended the fuselage so it's a longer airplane able to carry more. The PT-6 engines burn less fuel per hour than the R-1830, it flies faster than the stock DC-3, and its maintenance costs are much less. There is a reason that Basler has a backlog of BT-67 conversions.

I think had we continued developing piston engines, we'd see full FADEC for the engines that would make them more efficient for displacement, but I don't know how much further we could've gone because pistons have one problem - the propellers attached to them. Propellers can only go so fast. That's why the change to jet power - it can go faster at a factor that overrides the higher fuel consumption.

_________________

Well if you had the two side-by-side, at your free disposal (leave fuel and maintenance for your costs), yes, the BT-67 is a better performer in speed, and cargo. However you are incorrect with the fuel,as fuel flow in the BT-67 is HIGHER than in the DC-3. Secondly, seeing that the conversion is $6.5 Million per aircraft, that is a large amount of money spent on making an airplane that could otherwise cost between $90-200,000; one could obtain and bring into flying condition several DC-3/C-47's for that cost, heck, you could get a C-46 or two that could have equivalent speed, and carry much more cargo...

References:

Basler BT-67 Specifications

Also, the Piper PA-48 Enforcer was first flown in 1971, far into the development of turbine engines; in 1944, any jet engine of any kind would have been very spool-y.

_________________
© 2011 Peter J. Carlson, All Rights Reserved
"O! for a horse with wings!" -William Shakespeare

1) The What If question is for today, not 1944.

2) You're right, the -67R has a higher fuel consumption per hour. I was going off the old specs. However, considering that you get increase in speed, you end up with a lower fuel per mile usage.

3) I have 3 words for you -

PARTS

PARTS

PARTS

I'll say it again - PARTS. Yeah, $200,000 will get you a flying DC-3. It'll also get you a flying Convair 580 that will carry almost 3 times the payload. But what it won't buy you is the parts needed. R-1830's are getting scarce. Overhaul on one averages about $80,000. Props aren't much cheaper. Hourly operating costs for a DC-3 is about $1800/hr. A BT-67 runs about $1600/hr. That's a big difference and the difference is mainly due to the 12,000 hour TBO on the PT-6 versus the 2,000 hour TBO on an R1830 for the same overhaul cost.

_________________

Indeed parts are becoming harder to come by, but with 173,618 Pratt & Whitney R-1830s made, Im sure there will be enough engine parts to go around for a global fleet of 400 DC-3's for quite some time.

Not so much as to say the DC-3 is better than the BT-67, or vice-versa, but they are of equal 'betterness', so to speak. Indeed you save a certain amount of money per hour of operation, and overhauls and what have you, but operating two DC-3's with a small carrier will be much more cost effective than tow BT-67s, because you'll never reach $6.7 Million in engien overhauls in the DC-3. You must also remember that those TBOs for piston engines are pretty arbitrary, and one should overhaul their engines based on actual wear, data from oil analysis, and other maintence observations as opposed to some pre-set number.

_________________
© 2011 Peter J. Carlson, All Rights Reserved
"O! for a horse with wings!" -William Shakespeare

Sure but that's not how it works in the real world. Maintenance is done on hours in the real world. It's more cost effective.
Also it is about parts peter. Just because was 173,618 Pratt & Whitney R-1830s made. Not all that is going to be servicable today. And as the supply of those parts dwindles the price will increase.

_________________

What are you talking about the turbo beaver improves on everything. And there is a ton of them around, you just have to know where to look. With a PT-6 you get an increase on MTOW, range, speed, passengers, and a decrease in take-off, and landing distance. And depending on who does the conversion since multiple companies do it, you can actually get R-985 wheel beaver performance or better on a PT-6 amphibian beaver.

_________________

Not only that, but there's a reason that they're hanging PZL radials on Otters. They still build the things and they give a pretty hefty performance increase. If they weren't building the engine, I'm pretty sure they'd be converting them to turbine as well.

_________________

There were tens of thousands of R3350's made too. There's now less than 200 serviceable units left. Back in the 1950's and 1960's, they threw the things away after a certain number of overhauls. They got melted down or buried. As a result, it doesn't matter how many were made because there are far fewer available now. I've talked to guys who are operating the R-1830 right now, today. I've learned from them about overhauling and the problems they're running into. I've helped replace parts and try to find suitable replacements because the original part is no longer available.



You're right, 2000 hour TBO is arbitrary. It's rare that one makes it that far. In reality, most pistons are lucky to make 1000 hours. Thus, your costs for operation just went up 50%. Yet more case to go to turbine. At Air Tahoma, because Bud had a hard time for a while driving it into the crews that the power settings were to be obeyed strictly, one of the R2800s on the 240's was lucky to make 500 hours. They pulled one after 190 hours of operation (that's about 6 months of flying) for overhaul because half its cylinders were out of tolerance for compression. That finally seemed to make the point to the crews and when they started following the book, the first engine installed lasted 1500 hours. Still short of 2000 hours though, but a lot better.

_________________

One thing I can compare old and new engine tech to is diesel trucks. I started working on them when they just started to use a computer for engine control. Fairly simple at first, get rid of the fuel pump, the injector itself makes the pressure, a solenoid on the injector to control fuel flow thru it, a hand full of sensors, wiring and the computer. Simple and reliable.

Then in the early 2000s, they started with emissions equipment, namely a egr system. Remember autos in the 70s? Ya.
Now we have the diesel exhaust going back into the intake. Diesel exhaust is not very clean, but very "sooty". Now we have a egr valve(s), a cooler for the hot exhaust gas, more sensors, more wiring, more plumming- the cooler is water cooled, a new computer, and all that soot clogging up everything. We are constantly replacing egr valves, wiring, coolers.

In 2008, they came up with an idea to burn the exhaust gas in the exhaust system. We have the regen system. Inject fuel into the exhaust pipe, and it burns the dirty exhaust out of a filter in the exhaust system. Now we have a special exhaust system, filter, more sensors, piping/plumming, wiring, and a new computer(s). Not so simple. Many problems. Requires the driver to manage the system.

Sometime during all of this, the designers decided to replace the simple turbo with a not so simple variable unit. Again, with more sensors, wiring, plumming and such. Our fleet of 100 or so trucks, we go through one about every 2 weeks. The old ones, would last for years.
Also now we have several computers in the trucks, engine, vehicle, brakes, dash, lights, HVAC.

Maintenance is a nightmare. What used to be simple problems, now can take several days to find and fix. Most of the time we just live with the problems, cannot down the truck for days trying to find the issue.

Progress? Is today better? Are the engines cleaner? Are there more headaches?

Most of the problems you point to are due to government regulations being forced on the manufacturers, requiring them to meet unrealistic deadlines or standards in many cases and that ends up with massively faulty solutions.

The biggest problem with diesel engines right now is the Ultra Low Sulfur fuel. Actually, let me be correct about it - No Sulfur fuel. The standard for sulfur now is so low the refineries have to produce No Sulfur fuel to be able to meet the point-of-sale requirements. And once again, we can't do anything "standard" so our ULS Diesel is so much more "Low Sulfur" than the blend used in Europe that we can't import Diesel from anywhere else as a refined product, raising cost even more. At least with auto gas we can import it and then mix in the additives at the distribution facility as needed, preventing us from having to buy special batches from overseas refineries.

_________________

I have a friend up in northern Manitoba who flying beavers and otters for a hunting lodge, she tells me those PZL Otters are really something. The reason they switched to the PZL is because they were having troubles getting parts cheap enough.

_________________