If recips were made nowadays

PWR4360-59B said:

It is on the Continental diesel engines. And offered on some of the gasoline ones as well. Personally not sure if I would want electronics controlling the engine in a plane I'm flying, but thats me.

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In automobiles, the electronics seem more reliable than the mechanical systems they replaced.

swampyankee said:

In automobiles, the electronics seem more reliable than the mechanical systems they replaced.

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All fine and dandy till a nice EMP hits them, or that rare all electrical failure.

swampyankee said:

In automobiles, the electronics seem more reliable than the mechanical systems they replaced.

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Those mechanical systems were the main source of failure in the engines, and required constant maintenance the remain serviceable, which opened up another potential source of failure.

gumbyk said:

Those mechanical systems were the main source of failure in the engines, and required constant maintenance the remain serviceable, which opened up another potential source of failure.

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All engine are mechanical devices they are a mechanical system. There is no such thing as an electronic engine. Most all failures in cars and especially heavy highway trucks is because something went wrong with the electrical's.

PWR4360-59B said:

All engine are mechanical devices they are a mechanical system. There is no such thing as an electronic engine. Most all failures in cars and especially heavy highway trucks is because something went wrong with the electrical's.

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Most all failures in aircraft piston engines are because something went wrong with the mechanical accessories

gumbyk said:

Most all failures in aircraft piston engines are because something went wrong with the mechanical accessories

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And what does that tell us? Maybe they need to borrow some engineers from the old Chevy 235 days. Only thing to keep up on was points corrosion. Rare that anything else mechanical ever gave a problem.

PWR4360-59B said:

And what does that tell us? Maybe they need to borrow some engineers from the old Chevy 235 days. Only thing to keep up on was points corrosion. Rare that anything else mechanical ever gave a problem.

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yeah, nah...
I understand that you're sceptical of this 'new' technology, but times have moved on. The old magneto ignition as used on aircraft piston engines went out of automobile use over half a century ago. That Chevy 235? It had more modern ignition that your Lycoming 235...

PWR4360-59B said:

All fine and dandy till a nice EMP hits them, or that rare all electrical failure.

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The threat of EMP is largely imaginary. You should be more worried about the pilot spontaneously combusting. Modern computer controls are far more reliable and require far less maintenance then there mechanical for bearers.

The people in my parents' generation talked about valve jobs after 35,000 miles,

PWR4360-59B said:

All fine and dandy till a nice EMP hits them, or that rare all electrical failure.

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Short of a lightning strike or a nearby nuclear explosion, EMP is a really unlikely failure mode.

High performance and simplicity were pretty much at the opposite end of the spectrum using "old" technology.

And then you have redundancy. Modern computer controls in aircraft have a back-up, for commercial aircraft it may be triplicated.
Chances of both (or all three) computers failing at the same time are extremely remote.

One of the "old" fire trucks I drove had a V-12 gasoline engine with dual ignition for "reliability". two plugs in each cylinder with two twelve cylinder distributors. Each distributer would run the whole engine. However each distributor also had dual points and dual coils. Each set of points served 6 cylinders.
There was no problem with the engine running, getting it to run right was another story Just timing the two distributors and making sure the points were gapped the same was much more complicated job than tuning up an old Chevy 6.
The engine was a flat head, and certainly no powerhouse compared to it's size and weight.

from Speedville Home - Speedville
Back about 1970 I worked for while with an older gentleman who used to race flathead Fords in the early 50s. He said he had 4 engines. One in the race car, one ready to go in the race car, one in his street car being broken in and one on the shop floor being rebuilt. They just kept rotating the engines.
SOme of those old Flathead Fords needed a complete overhaul (not just a valve job) at 20-30,000miles.

Edit, my mistake, the LaFrance V-12 was not a flat head. What is was something out of left field.

Combustion chamber was a tall, narrow slot above the center of the piston.
Please notice that it was possible to remove the plates holding the spark plugs and remove the valves and grind the valve seats without removing the heads from the engine.

I guess my screen name means nothing. How about timing 4 mags?
I have a back ground with electronics, and numerical control machine tools, believe me I know what kind of faults happen with electronics. It was worse in the days of core memories but still not in the god territory these days. When you have a few atom separation between components in a chip it just doesn't take much to disrupt it. I would think the Fadec is a CAM system due to the environment with in an aircraft? So how many new cars suffer from electrical problems?
One real scary aspect of FADEC is hacking like has been done with some cars. I guess though in a plane the battery master would shut it off, well and the engine as well.

PWR4360-59B said:

I guess my screen name means nothing. How about timing 4 mags?
I have a back ground with electronics, and numerical control machine tools, believe me I know what kind of faults happen with electronics. It was worse in the days of core memories but still not in the god territory these days. When you have a few atom separation between components in a chip it just doesn't take much to disrupt it. I would think the Fadec is a CAM system due to the environment with in an aircraft? So how many new cars suffer from electrical problems?
One real scary aspect of FADEC is hacking like has been done with some cars. I guess though in a plane the battery master would shut it off, well and the engine as well.

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Why would you expose the engine controls to the web?

PWR4360-59B said:

I guess my screen name means nothing. How about timing 4 mags?
I have a back ground with electronics, and numerical control machine tools, believe me I know what kind of faults happen with electronics. It was worse in the days of core memories but still not in the god territory these days. When you have a few atom separation between components in a chip it just doesn't take much to disrupt it. I would think the Fadec is a CAM system due to the environment with in an aircraft? So how many new cars suffer from electrical problems?
One real scary aspect of FADEC is hacking like has been done with some cars. I guess though in a plane the battery master would shut it off, well and the engine as well.

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If I remember, the only car hacks have required physical access.

FLight engineers memories of the R-4360. http://www.enginehistory.org/Operations/R-4360Ops/r-4360ops1.shtml

a picture of the flight engineers station is there.
Planes that used the R-4360 used an early form of electric/electronic engine analyser to check ignition system.

According to a story on this website.
Any Airworthy R-4360 Wasp Major Engines? - Airliners.net
The R-4360 needed a compression check every 200hrs and they checked the timing and the valve timing at the same inspection.

a few more insights to the R-4360 are there too.

not quite the whole station.

FLYBOYJ said:

Not true - depending on the base the USAF FOD programs are huge, this I know as a fact, I'm the airfield FOD monitor at USAFA (among other things!)

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I agree with you. From being a young airman spending every morning doing FOD walks to Expeditor/Pro Super ensuring these were done, USAF takes FOD quite seriously.

I've read through that airliners.net thread, he has a few inaccuracies. And his funky valve timing settings are not documented in any airforce or manufactures manuals, maybe it worked who knows.
FADEC I'm sure since the manufactures of the large plane turbines have constant radio / satellite link to monitor the engines that they also have a way to also operate and tweak the fuel controls remotely. Hacking is not just an internet deal, when hacking into cars it can be done many different ways, some have done it remotely through the entertainment system, and then there is the onstar system that gives people remote control and diagnostics remotely, so proof it can be done by way of onstar too. And the hacker can be miles away. And on cars you have no way to shut it off.
I'm sure I will get an argument over that one. Do a good search on push button start systems, and how the computer runs everything. New cars are spooky things. Sure don't need aircraft in that boat.

Going back to the original question (sort of) I think it can be broken down into three parts.

1. Given modern material and knowledge what power levels ( or reliability/longevity goals) could be gotten out of new 'equivalent" engine to the last of the big piston engines, using the same fuel, as nothing better has been developed since for aircraft or ground vehicles.

2. Since 115/145 and 108/135 no longer exist (in commercial quantities) and even 100/130 and 100LL look like they are on the endangered list what sort of engine could be made using lower performance number fuel or alternative fuel?

3. Would any such engine be a viable commercial product in today's aviation market (using the fuel likely to available in the next 3-10 years) and at which levels of the aviation market?

Going back to 1, there should be little doubt that a more durable/reliable engine could be made using today's knowledge/technology/materials. It should be possible to improve somewhat on the power to weight ratios. Getting more power out of the same or similar displacements gets a lot harder. Those engines were already using about all the boost (supercharger pressure) the fuel would allow so increasing the boost very much is out. That leaves 2 other avenues. Increasing displacement by either using bigger cylinders or more of them. Bigger cylinders runs into problems real quick, the flame front in the cylinders only burns/travels so fast regardless of the year. Modern technology can't do anything about that (except perhaps using 3 spark plugs in each cylinder) and larger cylinders are harder to cool. You have more volume (amount of fuel being burned) to the area of the cylinder walls, head and piston top ( and the piston gets rid of a lot of it's heat to the cylinder walls). Adding cylinders adds weight, bulk and introduces a whole new magnitude of vibrations problems (22 cylinder version of the R-3350, two rows of 11?, 5 rows of R-44360 cylinders?) but with computers that may be easier to solve.
Comparing these big aircraft engines to motorcycle engines and thinking you can get the same power density overlooks a number of things. The small engines can rev much higher and make power that way, Their small piston are much lighter and don't travel anywhere near as far per stroke. They have a much better surface area to volume ratio for cooling. For example the old Kawasaki Z1 ahd a 1000cc engine that was good for 94hp when introduced. But each cylinder was only 15cu in in displacement while a R-4360 (or R-2800) used cylinders of 155cu in, over ten times the volume. The motorcycle turned 8000rpm which is just about 3 times the R-4360 rpm of 2700 (dry they let them go to 2800rpm wet) but the R-4360 was supercharged to 60in or double the atmospheric pressure the motorcycle was using. Disregarding intake losses the big engine was burning 2/3s the fuel per cubic in per minute the motorcycle was. trouble is the motorcycle had about 22.3 sq in of cylinder wall to get rid of the heat through while the big aircraft engine had only 108 square in of cylinder wall. or 15 cu in volume times 3 for the rpm means 45 cuin of fuel-air burned to 22.3 in cylinder wall, the aircraft engine was burning 155 cu in times 2 (for the supercharger boost for 310 cuin of fuel air with only 108 square inches of cylinder wall. A lot more heat has to leave each sq in of cylinder wall on the big aircraft engines. Granted I leftout the they cylinder head area (over square motorcycle engine, under square airplane engine)but this gives the basic idea.

The last way to make more power is higher rpm. I will get to that next time.

Diesel engine would be about the only option as you can push boost levels a lot higher.

Ryanjames17 said:

Diesel engine would be about the only option as you can push boost levels a lot higher.

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True but diesels have a problem with weight.

see: http://www.continentalmotors.aero/diesel/engines/cd300.aspx

300hp (actual 296.4?) is very good for a 182.3 cu in engine (3 liters) but the thing weighs 547.8 lbs.

You could get 300hp from a 550lb engine running on 91/96 (or even 80/87) back in the late 1940s.

Please note they are telling you the speed of the propshaft, they are not telling you the rpm of the engine.

Given a military budget and no "regs" as in F1, huge improvements. Ceramics could keep all the heat in the chamber without actually getting hot for example so lower cooling drag and higher power.