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-   -   Lycoming and Continental Piston Engines (https://www.pprune.org/tech-log/292952-lycoming-continental-piston-engines.html)

camel toe 20th Sep 2007 09:57

Lycoming and Continental Piston Engines
I recently overheard a rather experienced aircraft engineer talking about Lycoming and Continental piston engines used in things like Pipers, Cessnas, Robinsons etc.

He was rather damning of them from his engineers perspective and was of the opinion that they are an old design and I got the impression he felt they shouldn't still be being fitted.

I was just wondering whether there are any other engineers who work with these types of engines who can cast an opinion on the models we see in SEP's as I'm interested to hear more.

I have very little opinion as I'm not an engineer, this is purely a bit of research so I can learn a bit more.


Camel Toe
"Over Macho Grande?"

Pugilistic Animus 25th Sep 2007 16:48

my opinion is that these engine models are well proven well tested and simple to operate. so if it aint broke don't fix it, nothing is too new in aviation...autopilot DC-3 ca 1935 Cat II appch on AP Dc-8 1950's, most all of aerobatics 1929, autoland L-1011 ca 1965?.

anyway these OEM's have produced good reliable engines for a variety of airframes for many many years

fireflybob 25th Sep 2007 18:30

But compare these engines to the improvement we have witnessed with jet engines over the same period which are quieter and far more fuel efficient and use digital control

Lycomings and Continentals may be reliable and proven but they are old technology! When you look at the cost of AVGAS now it's high time we had a more efficient powerplant for light aircraft which are not susceptible to (for example) carb icing.

Maybe we need to go diesel, time will tell.

Say again s l o w l y 25th Sep 2007 18:49

If the pace of design by Continental and Lycoming were followed in the automotive industry, we'd all be driving around in Model T Ford's.

Conti's and Lycomings are rubbish and are outdated. Expensive and actually quite unreliable, especially in the larger models.

New ideas please!

Tail-take-off 25th Sep 2007 19:13

Simple question:

Would you buy a car with an aircooled flat four/six engine with no fuel injection or electronic engine management system? I suspect not.

The problem is the certification process for advances in technology are so expensive & long winded that manufacturers just keep throwing out the same old engines despite advances which could lead to improved safety.

Pugilistic Animus 25th Sep 2007 19:20

the FADEC controlled aerodiesels that use jetA have actually been through their reliabilty problems too, but let us introduce something much more important the bottom line and this new technology is expensive and would raise the cost of flight training in order that they meet aviation reliability [see far 23] if you have the money then there are many options, in fact just get a jet

basically they stopped working on piston recips BECAUSE of the jet engine!!!
also ,simple aircraft such as C-170 etc. are a great deal of the fun when you try to make them into 777 and a330s they just become a mess the systems are simple, the theory is simple and the maintainance is simple, and engine failure is very very rare, for any engine type---it must be so!

BTW my 88 volkswagen has been far more reliable than my 2004 nissan, never compare aviation with automobiles, those things are for the ground---who cares

Jetstream Rider 25th Sep 2007 19:41

The Lycoming aero engine was first designed in 1932 - its a seriously old bit of kit.

It is also heavy, fairly inefficient, noisy and vibrates a lot. The cylinder heads crack, they are prone to shock cooling, often have carburettors that ice up and fail often enough to be a continuous problem in any given year.

On the other had they are proven, easy to maintain and operate, and fitted to almost everything.

Contrast though the more modern engines like the Wilksch and the Jabiru and you can see there are plenty of improvements to be made.

Your car engine of even a few years ago is likely to be much more advanced, especially in terms of noise and vibration.

If it ain't broke, don't fix it - well my cart works fine thanks, think I'll ignore these shiny new "motor carriages" - they'll never catch on.....:}

Pugilistic Animus 25th Sep 2007 19:54

Remember also that preflight refers to checking for conditions conducive to carb or induction icing---yes I know the caveats due to the adiabatic cooling which can take place with ALL induction systems, but still, icing can take place in newer aerodiesel if the specific humidity is high enough and the cooling in the induction circuit is sufficient to reduce the temp to freezing. but as you know all GA planes with boots or a hot wing is certified to linger in known icing for hours!:rolleyes:

ATC Watcher 25th Sep 2007 21:18

Recent debate in my club : replace the Lycoming of a C172 for 15.000 euros or change it for a modern Thielert/Diesel for 30.000 euros.

Diesel Advantages : uses diesel fuel / jet A1 at less than half the price of Avgas, slighly less consumtion as well. FADEC/ single throttle management.

Disdavantages : no-ne knows the real potential of the engine 1000- 2000 Hours ? Electric failure and the engine stops ( it happens ) , Various reliability problems , recent change of engine block , no retrofit . when using Diesel, temparature limitations. ( but not with Jet A1) Weight limitations ( with full tanks the 172 becomes a 3 seater, etc...

This combined to the fact that Lycomings are very, very reliable ( after they pass the first 100 hours ) you can see why many are still replacing Lycomings instead of going for far newer technolocy engines.
But one day, someone will come with a good new engine , as 20l/h of leaded fuel per 100 HP is a bit old fashionned in the 21st century.
But reliability is what you want above all in a single engine.

barit1 25th Sep 2007 21:49

There is no more comfortable engine to ride behind than the Wasp Jr.


Just keep it supplied with fuel and 40-weight.

Shaft109 25th Sep 2007 21:56

Honda Aero Engine
I recently saw an article about Honda (being the world's largest engine OEM) working on an aero engine.
They did some research and the optimum layout was a flat 4 pushrod design! but with modern fuel injection technology, lightweight components FADEC etc. The basic layout it seems is still valid, but technology in general has moved on and should be encompassed.
Can't remember any figures so will have a root around.


27/09 25th Sep 2007 22:22

Interesting Discusssion

Comparision with auto engines is flawed. Yes, auto engines have shown great advances in technology, but look at the vast difference in the market size to spread the developement costs over.

Some of the technology on the auto engine doesn't operate quite so well in the aviation environment. Show me one auto conversion that has worked reliably in an aircraft? I don't count the Theirlet as successful yet, they have their issues.

Auto engines don't go to 100% output every time they operate and then run a 75% of rated power for hours on end.

Yes, your standard Lycoming or Continental isn't as smooth as your twin overhead cam 4 valve per cylinder electronic fuel injected chariot. The main reason is because the aero engine is a large capacity engine, this a product of the need for high power at low RPM. Why not run a gear box you say? Take a look at the reliability (low TBO) of gear boxes generally on aero engines of less than 9 cylinders.

A Lycoming or Continental may be old technology, genuine failures are rare and they generally go to or past TBO.

They don't stop when the gear is retracted either as happened to a Theirlet equipped aircraft recently. I know there were contributing factors, my point is they are simple and work well.

I understand that Lycoming has plans for a diesel engine but I suspect that until avgas prices get to much higher prices in the USA that progress wont be fast.

411A 26th Sep 2007 02:00

The right engine on my private aeroplane is a Continental GTSIO520 model.
340 BHP, spur geared propellor drive, fuel injected,turbosupercharged.
It was overhauled in 1990 by Butler Aviation in Tulsa, and after 1100 operating hours, still runs like a fine watch...very smooth and quiet.

I would have to say that it has provided quite good service for its age, I certainly have no complaints.
Overhaul cost?
Depending where it's done, the price would be anywhere from $25,000 to $38,000, including accessories.
The best part about flat six aircraft engines is that if cylinder problems are found, just bolt a new one (or more) on, and continue to operate.
The bottom ends of (especially) TCM Continental engines are very reliable.
How reliable?
PrinAir holds the record, set long ago.
This small airline operated 17 deHavilland Herons years ago, re-engined with TCM IO-520 engines.
FAA allowed time between overhauls?
4000 hours.
Close attention to detail by pilots and ground engineers allowed this long overhaul period.

Treat your piston aircraft engine right, and it will last quite a long time.
Do otherwise...expect large repair bills.

zlin77 26th Sep 2007 06:17

Following up on 411A's reply: I flew the DH-114 in Australia many years ago, ours were refitted with Lycoming IO-540's 290 hp. We operated at about 60% power in the cruise ie. 22"mp. & 2,200 rpm. Overhaul life was set at 3,000 hrs. and they were extremely reliable. Also operated Queenairs with the Lycoming GSIO-540, 380 hp.These were a different story for reliability but reasonable TBO's could be achieved with correct operation by the pilots. In nearly 6,000 hrs. of piston operations the only problem I experienced was a dropped valve in a Queenair.

PBL 27th Sep 2007 11:04

Originally Posted by 411A
The right engine on my private aeroplane is a Continental GTSIO520 model.

I think we knew that, didn't we?

Complex-system reliability is an art, not a science. I count IC engines as complex; I count a door, with hinges, as non-complex, although they can be quite as frustrating and unreliable.

I sat behind an IO360 for many hours, in mountains in winter, in weather, over ocean. (Well, not *that* many hours.) Cracked a cylinder, lost a mag. Ever worried? No.

These pieces of art have huge amounts of data behind them to tell you what they do. And they do their job as well as it can be done. Like a safety razor. Like a well-balanced kitchen knife.

Those are the reasons, and they are reasons that no "newer technology" can hope to match for a few decades yet.

The quandary is: how do we then progress? While answering that question, one might well remember that neither progress nor stasis is a necessary condition.


PantLoad 27th Sep 2007 12:05

No Preference
I've operated both Lycoming and Continental, and I've found both to be good, solid engines.

Currently, I operate a Lycoming IO-540 (300 HP) in my private aircraft (Cherokee Six). I fly night IFR over mountains...and most people think I'm an idiot (for that reason and possibly for others, as well...:)).

But, I believe that engine failures are due, primarily, to poor maintenance and improper operation. If you maintain the engine properly, do regular checks (including oil analysys, etc.), operate the engine as per manufacturers' recommendations, give it fuel and oil, etc....it usually won't quit. You have much higher probabilities of crashing for reasons other than engine failure.

In fact, I've never had an engine failure on a piston airplane. Had a rough-running Continental one time, but eased the aircraft to the nearest airport, made a safe landing, had the repairs made, and off I went never to have any further problems.

In most cases, engine failures are due to no fuel, contaminated fuel, no oil, intake icing, a destroyed and ingested air filter (due to poor maintenance), etc. Seldom does a well-maintained and properly operated engine just up and quit. And in the very few cases where it does, it was telling you for some time that it wasn't feeling well, and you simply weren't listening.


barit1 27th Sep 2007 12:44

There's a VERY interesting discussion here.

MrBernoulli 30th Sep 2007 00:01

Ooer! Have I been lucky? I have flown 1200+ hours on single engine pistons; about 1000 hours on twin pistons - all using Lycomings and Continentals. I have also flown 1000 hours on P&W Twin Wasps. Never had an engine failure on ANY! EVER!

Now flying ruddy great GE90s and RR Trent 895s ...................

missingblade 30th Sep 2007 03:25

Its time for the old technology to be replaced. The fact that they have millions of hours behind them do not make them efficient.

ForkTailedDrKiller 30th Sep 2007 03:59

Hmmm! There is some complete drivel posted in here.

Show me any other engine that can match the IO520 in my Bonanza for the combination of proven reliability, power to weight ratio, cost effectiveness, fuel economy at or below 10,000' over 500 nm - apart from a similar Continental or Lycoming!

My V35B trues 160 kts at 10,000' on 48 L/hr. There is no doubt I could get that back to 45 L/hr if I had an all cylinder engine monitor and ran LOP.

There is a very good reason they are still putting them in new aircraft.

Sure, FADEC would be nice but when the price is reasonable and the reliability is there.

Dr :8

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