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Lycoming and Continental Piston Engines

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Lycoming and Continental Piston Engines

Old 30th Sep 2007, 14:59
  #21 (permalink)  
 
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missingblade,

Its time for the old technology to be replaced. The fact that they have millions of hours behind them do not make them efficient.
That may be so, but it doesn't make the engines mentioned above unreliable either! Solid, reliable, easy-to-service bits of kit IMHO.
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Old 20th Feb 2016, 21:40
  #22 (permalink)  
 
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Question Oil analysis

Dear Pantload (yes, replying your post of 2007 if I see it well)..

Can you recommend a "good starting point" educational video (on youtube or elsewhere) about oil analysis, that a non-engine-overhauler pilot can also understand ? In general, what can we learn about oil analysis ? How is it done, and - importantly - how can I determine, whether the person or workshop who (claims) is doing it well, really does a professional job ?

Thank you,
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Old 21st Feb 2016, 18:33
  #23 (permalink)  
 
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Originally Posted by Rocker_7 View Post
Dear Pantload (yes, replying your post of 2007 if I see it well)..

Can you recommend a "good starting point" educational video (on youtube or elsewhere) about oil analysis, that a non-engine-overhauler pilot can also understand ? In general, what can we learn about oil analysis ? How is it done, and - importantly - how can I determine, whether the person or workshop who (claims) is doing it well, really does a professional job ?

Thank you,
This video should get you started

EAA Video Player - Your Source for Aviation Videos

Google Mike Busch and oil for more, quite a bit of information out there from him on all sorts of things. I would echo the comments others have made that really proper care and handling of the engine is key to longevity (even the awesome GO-480).
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Old 23rd Feb 2016, 06:58
  #24 (permalink)  
 
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Lycoming/Conti engines may be proven, reliable, etc., but so are hydromechanical fuel control units and horse carts.

FADEC engines will admittedly increase complexity but so are lots of other gadgets we have come to accept in the interest of economy and safety. And some possibilities of FADEC controlled engines actually reduce complexity, like replacing two magnetos geared to the engine with permanent magnet alternators and electronic ignition (or no ignition at all with Diesel engines).

("simple" carburetors have their quirks too. A club airplane lost engine power because of a stuck outflow valve (due to a broken valve hinge bearing) causing a buildup of pressure back into the induction system which effective killed the whole air/fuel mixing.)

For added complexity FADEC control would allow for single-lever power management which we have come to accept as standard in turbine engines, allowing optimum RPM/MP combination and reducing handling errors.

Current engine design owes to a time when there was no alternative to lots of displacement to turn props slowly. Today Rotax engines have run hundreds of thousands if not millions of hours with geared 4-cyl engines (admittedly of only up to around 125hp) and the Diamond Katana with its Rotax engine has captured a good percentage of the training market not least because it uses half the fuel of an O-200-powered C-150.

Liquid cooled engines would allow for more efficient cooling designs, theoretically even wing leading edge cooling providing de-icing would be an option (at least for larger engines).

Lastly it will become increasingly unfashionable (at least outside the US) to use something for recreation or transportation that uses an outdated amount of leaded fuel.

Even if we wouldn't mind using a poisonous additive in our fuel, lead content makes it more expensive to distribute AVGAS at least in the US because it has to be kept in separate distribution and storage facilities from non-leaded fuel, so it can't be pumped through Pipelines but has to be trucked or moved by barge (which then cannot be used for non-leaded fuels without cleaning AFAIK.) Coupled with a fringe market, this makes production of AVGAS unattractive for refineries, all factors increasing Price.

Honda finished their HondaJet after almost 20 years of designing, so maybe they'll come up with an aero engine some time.

To each his own. All who enjoy operating vintage machinery shall do so as long as they like but there should be a more modern option to keep GA flying viable into the future.
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Old 23rd Feb 2016, 12:54
  #25 (permalink)  
 
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Folks,
There is one vital point missed in all this, the aircraft that are piston powered, as new build aeroplane, are built in small numbers.
If there was a real market for a "modern" piston engine with all the bells and whistles, they would emerge.
There have been a few tries recently, an small HP Jet A diesels are being built in small numbers, for the small number of aircraft, to which they are fitted.
A lot of money has been lost by the original developers.
Auto comparisons are just plain silly, not only because the operating conditions are so different, but far more importantly, motor car engines are built in the millions, justifying the development costs.
Tootle pip!!
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Old 23rd Feb 2016, 13:13
  #26 (permalink)  
 
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"Auto comparisons are just plain silly, not only because the operating conditions are so different, but far more importantly, motor car engines are built in the millions, justifying the development costs."

So how hard would it be to take one of the most reliable engines and qualify it for GA flight?

I read an article a few years back about a Honda Fireblade engine (918cc, 120hp) which they ran for a million miles. When they stripped it, all tolerances were within limits.

Now I appreciate this is on a test bench and the atmosphere controlled, but I would expect that many of the advances in plating, injection, cooling, materials etc. would be perfectly applicable to GA.

Why develop from scratch if you can take something built in the millions and just tweak it for your environment and qualify it...?
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Old 23rd Feb 2016, 14:27
  #27 (permalink)  
 
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Because the work loads of a car engine and an aircraft engine are quite different.
Most likely just some tweaks won't do it.
Apart from that, if you want to use an engine on an aircraft it has to be CERTIFIED. And that means a lot of paperwork with HUGE costs for the manufacturer.
Is there a market big enough to offset those costs? Unlikely.
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Old 24th Feb 2016, 15:31
  #28 (permalink)  
 
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.............

Last edited by Radix; 18th Mar 2016 at 03:10.
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Old 25th Feb 2016, 00:40
  #29 (permalink)  
 
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I'm curious how great the efficiency gains from things like electronic ignition and fuel injection are on an aircraft engine. On a road vehicle, the computer makes a big difference be ensuring that mixture, timing, etc. are optimized all the time.

But it shouldn't be that hard to set up old-fashioned carburetion and ignition for maximum efficiency in one condition -- cruise flight. Once you have that, how much more will a bunch of silicon add?
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Old 25th Feb 2016, 00:46
  #30 (permalink)  
 
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In the commercial world, and upper-end business aircraft, VERY HIGH reliability and ever-improved fuel burn are paramount, because of their effect on operating costs. Airlines effectively underwrite the engineering and certification costs of manufacturers to achieve these ends.

In the private/training aircraft market, the cost pressures of the airline market just don't exist; ergo no such underwriting of the manufacturer's costs.

(Just send me a freshly overhauled R-985, an 85+ year old design, and I'm happy!)
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Old 25th Feb 2016, 10:13
  #31 (permalink)  
 
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But it shouldn't be that hard to set up old-fashioned carburetion and ignition for maximum efficiency in one condition -- cruise flight. Once you have that, how much more will a bunch of silicon add?

A lot more reliability for one thing, and better starting and power delivery in the take-off and climb for another. ECUs optimise the ignition timing and the charge in the cylinders hundreds of times a second, and the engine therefore runs at peak efficiency and reliability at all power settings and atmospheric conditions.

Carburettors are very crude mechanical devices and are prone to icing and malfunctioning. Can any piston aircraft manually adjust their ignition timing whilst airborne?, I've not heard of that, but have only flown SEP and MEP Cessnas and Pipers etc

Of course, efficiency is of little concern to the SEP and MEP world, and a simple, large displacement magneto engine will run with no external electrical power, which has a certain advantage.

It was similar in the car world, where we used to have large capacity engines to ensure sufficient power in all conditions. Nowadays with electronics we have engines half or a third of those capacities but which are just as powerful, and more reliable and cleaner. In addition they will adjust themselves to prevent pre-ignition (knock) and will not allow themselves to be overrevved etc.
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Old 26th Feb 2016, 17:53
  #32 (permalink)  
 
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Lycosaurus and ContiRex may be thought of as old and outdated, but I have to admit - I do like to fly them.

They do what I tell them to do and when I tell them, they are real easy to run and maintain by anybody with common sense, I am able to understand how and why they function, even guess quite quickly when they don't. The carb will give me direct feedback on environmental conditions, where already the injected engine is mysterious as my girlfriend.

The one I fly frequently now, already turned well over 50 years old and is still going strong on 3rd overhaul with no end in sight. I don't see a real progress in piston engine development either. I have to admit, I neither trust the car derived Fadec piston engines, nor things like Jabiru (which I would not call blessed with reputation anyways).

Maybe I have to fly too much turbine and jet, but I would like to see the old basic flying available for a long time. Call it sentimental, I call it joy of flying.
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Old 29th Feb 2016, 06:46
  #33 (permalink)  
 
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What we are realy interested in is the fuel consumed to create the horsepower ie the specific fuel consumption.

For a Lycoming IO-520F operating leaned to peak at 74% power the SFC is 0.413 lbs/HP/hr

For the R-3350, which is claimed to be one of the most fuel efficient spark ignition engines, the figure is somewhere between 0.409 and 0.398 depending on whose figures you use

Using the best figures I was able to find for a BMW 328i the figure is 0.446 for highway motoring, where it is only using 24 of its available 250 horsepower

So I would say the Lycomings/Continentals are not doing too bad. Spark advance (electronic?) and GAMI injectors to properly balance fuel distribution between cylinders would be about the only advancements possible IMHO. The stuff hanging off a car engine these days is mostly to satisfy pollutant control. I'm told they can't be operated at LOP because of the catalytic converter and O2 sensor, not much use to aviation where LOP is standard fare for the knowledgeable and properly equipt operator.
as 20l/h of leaded fuel per 100 HP is a bit old fashionned in the 21st century
If you can build an engine that puts out 100HP with a 20 litre fuel burn you've just found a way to print money, as that represents a SFC of 0.313, an absolutely unheard of number. .38 is about the lowest achieved, with .35 being talked about.

Last edited by megan; 29th Feb 2016 at 07:12.
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Old 2nd Mar 2016, 11:41
  #34 (permalink)  
 
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The notion that car/automotive engines are not up to standard for aviation use is now incorrect. Austro on the Diamond DA62 uses a 2 liter diesel engine made by Mercedes. The block, crank, conrods and pistons are unchanged form the car version. Todays modern automotive engines ith gasoline and diesel are pushing out hp and torque numbers unimaginable 10 years ago in consumer engines. Just look at Mercedes new 4 litre V8 in the AMG GTS. That specific power level was F1 territory 20 years ago.

The engine you buy today from Continental or Lycoming, while at face value looks unchanged for 50 years, the detail design and metallurgy means the engine is vastly different from its predecessors. 10 years or more Continental offered a blue printed line of engines at extra cost. That standard is now the norm.

However, diesels will ultimately kill of spark ignition engines for aviation, then they will be ale to standardise on 1 fuel type for the whole of aviation. Jet fuel.

Interestingly though Mazda has been experimenting with a compression ignition gasoline engine with a compression ratio of 18:1. It apparently has some super fuel injection system.
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Old 2nd Mar 2016, 12:04
  #35 (permalink)  
 
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Just have a look at the "lycosausus small brother", the Rotax 912.
This engine has water cooled cylinder heads to eliminate the thermal shock/cracking issues, it now also is available with a FADEC, fuel injected, with a computer controlled ignition.
At full power, the carburretor equiped version (which has a lot of issues with the carbutterors, wear, synchronisation...) still performs better.
Electronic fuel injection is great where automotive engines are operated, at low to moderate power. If you go full throttle / high power carburretors are not that bad. Same for ignition, if you go high rpm / high power you are anyway at a fixed timing, no need to do that with a computer.
Looking at the SBs and ADs the Rotax had over its life, our Lycontisaurs are damn reliable machines!

Production quality and price are the only real issues with our traditional engines, which were at times 40 year ahead of the automotive industry... It is just since the mid-80s that they have become much advanced, but mostly with respect to low power efficiency and emmisions. Even now you can still buy cars that not have hydraulic lifters compensating for valve expansion under heat...

The best thing you can do to improve our engines is to learn how to operate, especially how to lean them. That gives you more advantage than the car industry had in 30 years.
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Old 3rd Mar 2016, 00:22
  #36 (permalink)  
 
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I shall have the dissenting voice then....
They're heinously outdated pieces of equipment.
160HP-180HP out of 360 cubic inches? That is as bad as a late 70-ies Corvette.
4 pistons the size of saucers running 2300rpm?
40l/hr at 120kts? That's 18.3 l/100km...atrocious.
My claim to fame?
Non stop flight from just outside Boston to Naples, FL in a DA-42 Twinstar with 65 gallons used. 250 liters for 2200km for 11.4l/100km in a twin engine aircraft.
I've always liked the 1.7L more then the 2.0L Thielert.
In any case these engines are the Mark 1.0..lots of room for improvement still.
But for fuel consumption and noise levels...wow.

http://www.pprune.org/private-flying...flights-2.html
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Old 3rd Mar 2016, 01:14
  #37 (permalink)  
 
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A few thoughts:

It's true that most older aircraft have 'atrocious' fuel consumption, but that's as much to do with the airframes as the engines. I've heard it said that Rotaxes are not really much more efficient than Lycosaurs and Continentals in the cruise, but that their advantages lie in climbs and circuits... Where admittedly a lot of aircraft spend a lot of time. Particularly training aircraft.

WRT car engines... if you take an engine and run it at 20% of peak capacity, it's not surprising if it lasts for many thousands of hours with little wear. But what if you put it in your aircraft and run it at 100% for minutes at a time, then spend the rest of the time at 75% power?

There are older aircraft that allow you to advance/retard the ignition; presumably it was felt that 4 levers (throttle, carb heat, mixture, pitch) was already enough for any mortal to get their head around.

Certification may not prevent engine development, but aircraft certification prevents you from just bolting a 100hp rotax to anything that is designed for a 100hp continental. Contrariwise, if you were to buy a new aircraft, would you want an engine from an unproven manufacturer who might go bust at any moment - thereby grounding the whole aircraft potentially forever - or would you get an engine from a vendor who's been around for the best part of a century and for which 3rd party manufacturers supply approved parts? If an aircraft cost £10,000 and was expected to last 10 years you might well chance the modern engine with a slightly lower fuel burn, but as a new Cessna costs fifty times that and might be expected to last 50 years, knowing that the powerplant is likely to be supported for decades to come is a big issue.

Personally I fly behind a VW engine which, five decades after it was made, is likely to have parts support for many years to come.
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Old 4th Mar 2016, 12:59
  #38 (permalink)  
 
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Rocket, this will help you

http://www.lycoming.com/portals/0/te...s_11261971.pdf

http://ehfc.net/LycomingEngines.pdf

I cannot fault Lycomings and Continentals, true they burn more fuel, but they have decades of use behind them, they are known, simple and reliable, what more could you want.
As for some of the later diesels, they are none of the above.
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Old 6th Mar 2016, 18:41
  #39 (permalink)  
 
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I have flown many pleasant hours behind Lycoming and Continental engines as well as with Pratt&Whitney and Wright radial engines, but their time is drawing to a close. If you wish to fly in the Artic regions, you may have great difficulty in finding AVgas at any price. You may find that the green fiends have made it impossible to add any lead content to your Avgas, and that your engine actually needs just a touch to keep running.

There are new diesel engines on the horizon that are capable of using a wide range of turbine/diesel fuels. My personal favorite is the DeltaHawk engine which has been under development for the last 20 years.
It has been a painful process to watch from the outside and has cost a small fortune, but they are drawing very close to the certification target. It is not enough to have a brilliant concept. In the end, you need to develop a wide base of engineering knowledge, qualified suppliers, proper industrial methods, proper trust from the certifying authority, etc. A very daunting gauntlet for a start up company. I wish them well.
DeltaHawk DH180A4 | DeltaHawk Engines
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Old 7th Mar 2016, 07:28
  #40 (permalink)  
 
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Unleaded Avgas

The target FAA certification date for unleaded avgas remains 2018. We'll see. According to an AOPA article from about 6 months ago, progress has been steady. So probably there is no need to worry about gasoline burners going the way of the dinosaur on account of leaded gas! Running unleaded is going to solve more than one problem.

The arguments for and against EECs for aero piston engines are well-known and long established, though perhaps somewhat less so than the tried and true magneto itself.
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