# Western engine reliability



## Tante Ju (Jan 15, 2013)

Question arose in different thread. Supposedly Western engines had more lifespan than Soviet, German or Japanese engines. I open this thread to find out truth of these engines. What was TBO, how long they lasted in frontline conditions (not training flights or manufacturer sell brochure)



> Merlin engine (Merlin 46)
> 
> However, most of all the technical personnel of the regiments were dissatisfied with the power plant of the British fighter—the Merlin 45 and 46 engines. In particular, the summaries say that the “engines function fully satisfactorily. The strong side of the Merlin engine is the fact that a PRD has been mounted on it, a regulator for the quality of the [fuel] mixture.” The engine had another quality as important to technical personnel as simplicity of service—assembly and disassembly of the engine was simple; there were no particularly difficult approaches to it. The engine started easily, its RZ-5 spark plugs worked for up to 50–60 hours which, as the mechanics noted, was also a good indicator. However, these same spark plugs had a “very weak electrode.”
> 
> ...



Source. Spitfires over the Kuban


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## Tante Ju (Jan 15, 2013)

Allison engine (in P-39)



> A. S. What about the engine in the P-39. Was it weak? They say that it was unreliable, it was never good for the recommended 120 hours, and it “threw” connecting rods.
> 
> N. G. We had Allison engines. They were powerful, but . . . the engines in the Cobras were unreliable, especially early on. These were on the English variants, the Q-1 and Q-2. Their engines were weaker. After the first three or four air combats, all ten Cobras were laid up for engine repairs.
> 
> ...



Part 3

Allison engine in P-40



> N.G. Even during the war I recognized the fact that the Allies considered it inadvisable and almost impossible to conduct aerial combat in the P-40. We considered the P-40 to be a full-fledged fighter plane.
> When we began to use the P-40, we immediately discovered two deficiencies that reduced its value as a fighter. 1. The P-40 was a “slug” in acceleration, rather slow to acquire speed. This weak dynamic resulted in a low combat speed. It had trouble maintaining the speed required for combat. Speed is essential for a fighter. 2. It was weak in the vertical, especially the Tomahawk.
> We compensated for poor acceleration by holding the engine at higher revolutions and cruising at a higher speed. We corrected the second deficiency by removing a pair of machine guns. That was all. The fighter came up to par. Now everything depended on you, the pilot. Keep your head! And work the stick intensively. *It is true that because of our unforeseen operating regime the engines had a limit of about 50 hours, and often less. Normally an engine might last 35 hours and then it was replaced.*



http://lend-lease.airforce.ru/english/articles/golodnikov/part4.htm


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## Tante Ju (Jan 15, 2013)

Griffon engine 


Spitfire trials from 1946. First engine develops rough running after 41 hours. Second engine fails 61 hours.







Trials at boosted setting during war. Engine fails on first flight made.

RAE 1501



> 4.3 Spitfire XIV (Griffon 65)
> 
> Spitfire R.B.176, as received from Squadron, was operating at +19 lb./sq.in. boost and 2,750 r.p.m. (Griffon 65; 5-bladed Rotol propeller). It had a circular external rear view mirror with hemispherical fairing; no ice-guard on the air intake; a whip type aerial behind the hood; a radio mast projecting from the lower surface of the wing forward of the starboard aileron; another mast set in a fairing under the fuselage; small type bulges over the 20 m.m. cannon and the cannon stubs faired; the machine gun ports in the leading edge sealed. The 30 gal. auxiliary fuel tank (slipper type) was removed for the purpose of the tests.
> 
> ...


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## Tante Ju (Jan 15, 2013)

Sabre engine... 

RAE 1501



> 4.1 Tempest V (Sabre II.)
> 
> Considerable difficulty was experienced on this type of aircraft due to unserviceability. Three aircraft were received from Squadron.
> 
> ...




Curiously - it was famous pilot Eric Brown flying one of Tempest. He recalls (also where funny story when he landed).



> About mid-June a crash programme was initated to improve the low-level performance of the Spitfire, Tempest V, and Mustang III by using a specially developed 150 octane aromatic fuel to give abnormally high power for strictly short bursts.*The engine attrition rate would of course be high, but the urgency of the situation demanded drastic measures.*
> 
> I was very involved in these exhilarating trials requiring high speed runs at ground level, during which the Spitfire XIV with its Griffon boosted to +19 lb reached 365 mph, the Tempest V with its Sabre boosted to +10 1/2 lb hit 405 mph, and the Mustang with its Merlin boosted to +25 lb actually attained 420 mph. During these trials I was flying Tempest V JN735 on 26th July at just after 7 o´clock in the evening, and had completed a 5 min level run at 1,000 ft at +9 lb boost, 3,650 rpm, which the airscrew pitch lever fully forward. I then climbed through cloud to 6,000 ft, where the second run was made under similar conditions, for it was known that the V.1 could fly up to almost 10,000 ft.
> 
> ...



The Hawker Tempest Page


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## parsifal (Jan 15, 2013)

Cant help much Im afraid. i do have a secondary source that says the average life expectancy of allied fighters in 1944 was 8 months.


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## Jack_Hill (Jan 15, 2013)

Hi.
Intricated thread indeed.

Bit lost with such an amount of interesting questions, so i stopped reading after third post, but i'll read farther later.
Seems that the two first post concerns Russian testing : Merlins and Allisons.
So, whe may ask a question maybe.
Did testings occured in Russia, Ukrainia, Siberia or anywhere else in Ussr ?
wich season ?
Wich fuel ?
Wich lubricants ?
Did tests occured within usual low alt Russian aerial warfare or else ?
To me, any well designed, high performance engine breaking at 60 hours (of course considering the conditions of use) simply means an overhaul revision at 40 hours of run.
And engeneering hard work to solve that lack of reliability and/or quick availabilty for new engines replacement.
But i may be simplist.


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## Juha (Jan 15, 2013)

Hello Tante Ju
did you miss the last chapter of Zlobin's article

_"It is worth noting that the mastery by the flight crews and technical personnel of the exploitation of the Spitfire and Merlin 45 and 46 engines *was accomplished directly in the regiment*. The senior squadron technicians and regiment engineers by specialty were the basic supervisors in technical training, *despite a lack of special literature on the equipment*. A review of mistakes in use of the equipment was conducted regularly with both the flight crews and mechanics of the regiment. These reviews were important, because *no one in the division or the regiment had any experience in the repair and use of the aircraft and engine.* Thus, every new revelation, after careful discussion and consultation, was quickly implemented on the equipment. In any event, the following conclusion was reached concerning these monthly reviews of the use of the Spitfire: “The regiment’s technical personnel coped well with both exploitation and repair, and in the future, if they had had occasion to service this same type of aircraft, could have completely fulfilled their obligations.”_


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## Shortround6 (Jan 15, 2013)

The Russian pilot being quoted fully admits the Merlin and Allison engines were NOT being run according to manufactures recommendations, which rather affects the expected life of the engine. 

Tomahawks used the early "C" series engines which had a number of problems, The Kittyhawk started with the -39 engine which was an "F" with a number of improvements. Later Kittyhawk's used several newer versions of the Allison P-40Ks used an F4 instead of the F3 and the M/Ns used F20s, F26 and F31 engines. 

"Vees for Victory" claims that F26 was rated at 750 hours between overhauls by the end of the war.


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## davparlr (Jan 15, 2013)

If I remember correctly, Bud Anderson stated he never aborted a mission due to aircraft problems. He flew the P-51 "Old Crow".


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## DerAdlerIstGelandet (Jan 15, 2013)

parsifal said:


> Cant help much Im afraid. i do have a secondary source that says the average life expectancy of allied fighters in 1944 was 8 months.



Yes but was the engine or the airframe?

I do however find it hard to believe that any of the major engines from the major nations (USA, England, Germany, Japan for example, but not to name them all), would last such a short lifetime. Don't take me wrong, I am sure that routine maintenance was required on all of them on periodic limits, but I am sure they could all be measured in hundreds of hours for total lifetime during the war.

Whether the airframe survived the war for a very long time is a whole other problem though.


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## bobbysocks (Jan 15, 2013)

Shortround6 said:


> The Russian pilot being quoted fully admits the Merlin and Allison engines were NOT being run according to manufactures recommendations, which rather affects the expected life of the engine.



the first time the air force personnel witnessed a VVS scramble ( in poltava iirc) they didnt have too many good things to say about their practices. pilots got into planes, as soon as the engines were started they were immediately pushed to full throttle and the plane airborne. neither the pilots or ground crews did any pre-flight checks or engine warm up. the pilots took off in the direction the plane was facing at the time regradless of the wind direction ( cross wind, down wind..didnt matter) or placment of other ac. there was no co-ordination from a tower...ac would often criss cross each other taking off. whether this was a show for the yanks or standard practice...??? but if it was a sample of how vvs treatment of machinery then its no doubt they had a higher attrition rate for ac engines. in contrast to comments i have heard and read about us fighter groups...the planes looked weathered and well used but mechanically they were as goodor better than when they rolled off of the assembly line. a funny story about a vvs pilot...

The Russian Pilot


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## parsifal (Jan 15, 2013)

Im not sure, but would assume its the airframe. I also would find it hard to believe that a complete engine overhaul would be needed after 50-60 hours. I dont have any experience with aero engines, of any kind, but I do have some experience with auto engines, including supercharged and turbocharged engines. Just enough to get myself into trouble......

Its a more believable propoosition that fuel quality issues and overtaxing of the boost, or the use of water methanol or other fuel enhancements might very well burn too hot, or fast, or not fast enough. Its a somewhat different matter with supercharged or turbocharged engines. these systems are basically force feeding the fuel air mixture into the cylinder. If the cylinder is not designed or strengthened to take the additional fuel and air being forced into the pot, there is a real risk of blowing the cylinder heads off the engine. Thats why most turbos have to run on a fairly restrained overboost. In automotive racing it also usually means you have to derate the engine.....reduce the compression ratio and/or the boost rating of the engine. I would expect that an engine being run above its boost levels on a sustained basis, or running a turbo using higher octane rated fuel on a sustained basis is bound to have reliability problems. You can partially offset that risk by using higher standards of construction in the engine build....so called blue printing of the engine. Better stronger components does help if you absolutely need to run the thing over its design specs. 

Poor componentry, overtaxing of the engine, overrated fuel, poor quality fuels are all going to put the engine life at risk. I would expect that this basic understanding would easily apply to aero engines in the same way as they do to high performance auto engines. Fuels usually lead to early burn out of the upper parts of the engine.....particulalry injectors, valves and valve seats, perhaps even cylinder heads and pistons and/or piston rings . Harder to believe that fuel quality would result in failures of the long engine.....the conrods, the bearings or the crankshafts. it is possible though, if the fuel resulted in severe knocking of the engine during the firing cycle.

As the war progressed, all the combatants put their engine types at greater and greater strains, as the very utmost in ppower was demanded of them. Hard to assume that any given design was any worse or better, although older or smaller engines may well have a lower initial design spec. I would however expect the allies to be in a better position overall, as their quality control and componentry were likley to have been better quality at wars end than either the axis or the Soviets.


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## Jack_Hill (Jan 15, 2013)

And climat.
Engines, air inducts, and cooling systems hates ingesting dust and much more, clouds of dust and small stones during dry, hot weathers.
permanent snow is another factor.
Inducing high percentage of water in the mix.
"they didnt have too
many good things to
say about their
practices. pilots got into
planes, as soon as the
engines were started
they were immediately
pushed to full throttle
and the plane airborne.
neither the pilots or
ground crews did any
pre-flight checks or
engine warm up. the
pilots took off in the
direction the plane was
facing at the time
regradless of the wind
direction ( cross wind,
down wind..didnt
matter) or placment of
other ac. there was no
co-ordination"
Hi, Bobbysocks : So you already knows what it is biking along my helder brother !
How can you know it ?


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## Jabberwocky (Jan 15, 2013)

Tante JU, this is very disengenious of you.

1. The Merlins in the Russian Spitifres were neither new nor were they maintained to the same standards as in the UK. You have no idea how much time the engines had on them before they went to the Russians. 
2. The V-1710s in Russian P-40s experianced a similar situation
3. You're using test flights made at high boost with 150 octane engines as representative of regular combat operations. Griffon 65s at +25lbs, Sabre IIs at +11 lbs, Merlins at +25 lbs. Put more stress on these engines and of course the failure rates are going to increase.
4. You're pointing to specific examples and then generalising into a trend. This is dangerous territory.

How about some engines in regular service, well maintained by the airforces of the country that built them? How about more than just a few individual examples?

The R-2800 manual from 1942 suggest a conservative TBO of 350-400 hours. Rolls-Royce suggested a TBO of about 240 hours for the Merlin, but only around 30% of engines actually reached this figure. In service Packard V-1650s had a TBO of 110-180 hours in the Mustang in Nth Africa/Italy. 

An interesting read, if somewhat long, on the Axis History forum, from 2006. Kurfurst and Huck tried exactly this approach and see how far it got them:

Axis History Forum • Reliability of aircraft engines


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## CobberKane (Jan 15, 2013)

When Eric Brown flew the La-7 at the war's end he described it as having excellent performance and handling, with the proviso that it did not appear designed to last as long as US and UK contemporaries. Anecdotally, the Soviets did not seem to expect their aircraft to last too long - a function of the strategic situation, I assume.


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## Jack_Hill (Jan 15, 2013)

www.ww2aircraft.net/forum/modern/mig-21-still-unpleasant-surprise-cope-india-exercise-35208.html
Things seems to have changed.
Not so easy to get into Russian mind.
New tactics ?
But off-topic, sorry.,


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## Shortround6 (Jan 15, 2013)

Rolls was saying in 1939 that a fighter Merlin _could_ go 240 hours and Bomber engine 300 hours. By 1944 they were saying 300 hours and in 1945 360 hours for the fighter engine. Bomber engine life was supposed to be 360 hours in 1944 and 420 hours in 1945. Even if we cut that to 60% for the _average_ that would be 180 hours in 1944 for a fighter engine and 216 hours for a bomber engine. 3 1/2 to 4 times what is being bandied about. 

Modern light plane engines are good for around 1500-2000 hours for Continental and Lycoming engines. It is however, quite possible to have to replace a piston or cylinder well before reaching overhaul. FlyboyJ would know much better than I but running engines _past_ their service life may be frowned on by the FAA no matter how good the oil looks. 

Once again these are _suggested_ MAX lives, not money back guarantees. In peace time if the engines get a reputation for not lasting near what the "brochure" says the airframe company may start fitting a competitors engine. You can only exaggerate so much in your advertising before it blows up in your face. 

Great strides were made in metallurgy and testing during 6 years of war. Post war most of the R&D went into long life rather than power but it seems a bit strange that engines that could only give 50-60 hours of life in 1944/45 could give hundreds of hours of life if not over 1000 hours in post war airliner service. Not so strange if the engines were giving 400-600 hours in the last year of the war. 
Post war civil R-2800s were "rated" to use water injection for take-off, I have no idea how often they actually did it.


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## Aozora (Jan 15, 2013)

The quotes on the Merlin are, as suggested, disingenuous because the conditions under which they were run and the engine handling were all below the normal levels; this statement


> According to the account of Nikolay Isaenko, having begun to fight in August 1943 _in equipment that had been worn in the process of training and ferrying_, the 821st IAP entered combat work with already “problem” engines....Spare parts were in short supply for the Merlin, for the Rotol propellers, for coolant and oil radiators, wheels, and instruments.


 makes it quite clear that the engines were already well worn before reaching operations and had clearly not been serviced properly due to a lack of spares. 






Another Russian opinion on the Merlin in the Hurricane:



> A. S. What about the English engine, they say it was unreliable?
> 
> N. G. *It was a good engine, powerful and sufficiently reliable. The engine worked very clean.* It had exhaust stacks and flame suppressors, mounted like mufflers. This was very helpful because it prevented the pilot from being blinded. In this regard our own aircraft were significantly deficient.



Part 1

So, sure, I'll admit the average life of every Merlin engine built was about 50-60 hours *after* they had been worn out in operational service, subjected to more abuse during training and ferrying, then badly serviced because of a lack of manuals and spares. 

Allison in P-40 



> N. G. The Tomahawks had the Allison engine, not very good, but in itself powerful. As one pushed it to full RPMs, toward maximum output, it would begin to “make metal” [tiny metal particles in the oil]. *But apparently it was our fault because, we were told, we had insufficient “oil culture”. Later the Americans modified the engines and in the Kittyhawks the engines were more powerful and reliable.*
> 
> Our “oil culture” also was improved as oil heaters, filtration devices, and special filler devices appeared. Our oil heater was cleaner than the equipment at the aid station. The regiment engineer was vigilant! Everyone wore white smocks, they used rubber mats, [paving] stone ramps, they constantly struggled with sand and dust and wouldn’t let them close. They filtered the oil two and three times in the oil heater and two more times during the oil filling process. Even the “pistol” [dispenser] at the end of the oil filler hose had two covers, a thin white one and a thick canvas cover over the top of it. *In principle we did need to improve our handling of oil, even while flying the Hurricanes. Its engine also was sensitive to oil, and when the Allisons arrived we had to raise our “oil culture” even higher.*
> 
> ...



 Part 2

P-39 (also left out)



> A. S. Was the engine capable of high altitude?
> 
> N. G. Fully. 8,000 meters without problem, and neither we nor the Germans flew higher than that.
> 
> ...



 Part 3

Guess the Russians had to learn some engine maintenance.


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## davparlr (Jan 15, 2013)

Military pilots, while respectful, for the most part, of their aircraft and operate them within limitations under normal circumstances, have no compulsion against pushing performance past specs if they feel it is necessary for an important or vital maneuver. Fighter aircraft are often reported as over "g" ed and I am sure engines are over stressed as often. Maintenance activity are based on assumed operational environment and maintenance guarantees, like battle strategy, last only until the first shot is fired.


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## bobbysocks (Jan 16, 2013)

and because of that would the airframes have been considered "war weary" long before the engines ( generally ) were in need of overhaul? did they ever "overhaul" an engine? with production going full tilt would they have wasted the time and effort on rebuilding an engine from the crank up or just throw that one in the junk pile and do a complete engine change?

and why does the last word in the first line sometimes get repeated??? lol



Jack_Hill said:


> Hi, Bobbysocks : *So you already knows what it is biking along my helder brother *!
> How can you know it ?



i do not understand what you are asking me, jack. how do i know what? what i posted?


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## Jack_Hill (Jan 16, 2013)

Post #11
"they didnt have too
many good things to
say about their
practices. pilots got into
planes, as soon as the
engines were started
they were immediately
pushed to full throttle
and the plane airborne.
neither the pilots or
ground crews did any
pre-flight checks or
engine warm up. the
pilots took off in the
direction the plane was
facing at the time
regradless of the wind
direction ( cross wind,
down wind..didnt
matter) or placment of
other ac. there was no
co-ordination"
Replace plane or a/c with motorcycle and you'll have the answer.
Just humour, no big deal.


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## parsifal (Jan 16, 2013)

I dont get the issue about east front. Attrition to non-combat related causes for all combatants (with possibly the exception of the Finns) was exceptionally high. German attritional losses on the east front for example, ran at about 20-30% of the force structure every month, depending on the weather conditions and intensity of activity. Soviet losses were similar, so from the point of view of loss rates, engine reliability had little or no effect on Soviet force structures. Neither did it have much effect on operational readiness rates. German readiness rates according to Hayward were typically about 35-50% climbing to 60% occasionally on the eastern front. Soviet readiness rates were certainly no worse than that , usually above 50%. 


Another way to look at this issue on the Eastern Front, might be to look at sortie rates.....how many aircraft were needed in a random sample to fly x amount of missions. if the number of aircraft (attached to the formations concerned) needed is higher to fly say 100 missions, then we can safely assume a lower readiness rate, and by extension, a lower level of engine reliability.

Im not aware of a lower or worse return for the Sopviets in any of these categories.


I think this whole issue is just a big crock......a beat up to try and trumpet superior german technoilogy, or to try and bring allied (and Soviet ) reliability levels back to their own (generally) miserable levels.


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## Shortround6 (Jan 16, 2013)

bobbysocks said:


> and because of that would the airframes have been considered "war weary" long before the engines ( generally ) were in need of overhaul? did they ever "overhaul" an engine? with production going full tilt would they have wasted the time and effort on rebuilding an engine from the crank up or just throw that one in the junk pile and do a complete engine change?




Please note the word "average". For every green pilot that cracked up a plane in it's first week on base another plane had to go *16* months to get an 8 month _average._ 

British had overhaul facilities in several areas around the globe as did the US. There are pictures of a Merlin overhaul "facility" in caves near Cairo, Egypt. Units (squadrons) did not overhaul engines as a general practice, There may have been exceptions. Engine swaps were much more common but the engines swapped into the planes maybe from the factory or from an overhaul facility.

In North Africa the British broke down several hundred ( as many as 600?) Merlins in order to supply the US forces with parts for their Merlin powered P-40s. US planners had only acquired about 20% more engines than complete planes which was considered too low. Many planners thought there should be 50% more engines than complete aircraft. 

I have checked a few figures and it appears in 1942 that Chevrolet in 1942 in addition to supplying 4058 R-1830s also supplied the equivalent of another 16% in spare parts and Studebaker was about the same percentage of parts over and above complete R-1820 engines. Allison was supply a much higher percentage of spare parts.


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## GregP (Jan 16, 2013)

This sounds very funny. Since we build Allisons, we have the books and the records of overhaul ... and we talk with and sell to (mostly used to sell to these days) former WWII pilots who have Allison, Merlin, P&W, Wright, etc. - powered aircraft from WWII. For instance, we did the engines for Lefty Gardner and all the flying P-38's except the Red Bull unit.

According to our information, wartime TBO for the Allison was 250 - 400 hours depending on the dust conditions. Wartime TBO on Merlins was 200 - 300 hours depending on dust conditions. In typical wartime forward area airstrips, typical TBO was 250 hours for both.

Alllisons have cylinder liners that need no maintenance, but the Merlin needs the cylinders tightened up every 25 - 30 hours or so. Nothing tough about it but, if you DON'T do it, the Merlin will experience premature problems due to cylinder leakage. From the Merlins and Allison we operate today, both are very relaible and give plenty of warning when they are starting to want attention except in very unusualy circumstances.

I have had friends with P-51D Mustangs experience issues with a newly-overhauled Merlin at 40 hours ... and other friends who got 450 - 600 hours on them without a problem, but following recommended maintenance procedures and recommended operating procedures. We have some Allison customers with 1,200 hours on Allisons we have overhauled and most get 800+ hours on them if they take care of them and operate them properly. That is peacetime operation.

According to Lefty Gardner, Joe Foss, Bug Mahurin and others the Allisons, Merlins, Wrights, and P&W's were quite reliable and usually lasted to recommended TBO when maintained and operated properly. They almost never lasted LONGER than reconnended TBO because they were military and were taken out of service for overhaul when they reached TBO unless they were in a "squadron hack" in a combat zone.

Yes, you can kill a Merlin, Allison, or ANY big piston by not operting or maintaining it properly, and you can do it in less than 50 hours easily. I can kill an Allison in 20 minutes if I want to. When you give people aircraft and they operate them without training or even reading the book, I have no doubt the engines were a source of trouble. 

At the Planes of Fame, we operate a Nakajima Sakae 21 engine in our A6M5 Model 52 Zero. It is the same engine the aircraft was captured with in 1944 and the same propeller. It was overhauled by Nakajima (now Fuji Heavy Industries) and we operate it per Nakajima recommendations. The people who had a Zero at the end of the war and never took the trouble to learn the book didn't have them long before they were unserviceable.

Engine reliability depends almost entirely on the use and maintenance of same. Dito the propellers and guns.

I flew radio control aircraft for about 18 years before stopping (would like to start again ...). Never had an enguine failure, but saw them regularly by people who didn't know how to run the 'engines. The worst thing I had happen was my tuned pipe fell off because I didn't tighten the bolts properly. I landed the plane (now a LOUD plane), retrieved the pipe, installed new bolts and flew it again within 10 minutes. Never happened again. It works for RC engines, too ... use and operate them correctly and you will have a good experience.

Treat them badly and you will be on the ground watching other people fly.


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## parsifal (Jan 16, 2013)

That is such a good post GP. What engines were designed such that they would have a shelf lif of 50 hours or less. the only types i could think of might be the cutting edge types, like the early jet engines. I would think that nearly all the WWII era internal combustion engines would represent evolutionary changes to existing proven technology. The chances of these engies having an inherent design fault that would reduce their service life to 50 hours or less seems very remote to me.

I believe that the Axis constructors began to suffer serious QA issues as they plunged closer and closer to defeat. The Germans themselves talk about these problems. Would it not be likley that given an engine that, as designed should have a service life of 250 hours, but with dodgy QA in the componentry, might not suffer a higher instance of early failure?


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## GregP (Jan 16, 2013)

Thanks parsifal. You are right about early failures of Axis engines late in the war. Think Ta-152. They were all "prototypes" presed into service due to the wartime situation and never were more than about 25 flyable at one time. They didn't fly long and only two (Ta-152C's) were opertional when the war ended. But the engines might not have been the issue as much as lack of engine maintenance. We may never know. It wasn't the propellers or the airframe and I refuse to believe the Germans couldn't come up with a good radiator. That leaves the powerplant as the main culprit. I suspect maintenance since the Jumo 213 wasn't a bad engine, but DID require maintenace, just as our WWII engines do today.

I have a comment about Soviet engines. They had short TBO and still do. Part of the trouble was the way they were operated and maintained. I have seen film clips of Soviet crewmen filtering aviation gasoline through cotton just to get wood chips out of it! The Soviet gas was low octane for the most part, poorly filtered, and full of contaminants. The containters were not washed between uses and the maintenance was crude. Freezing arctic conditions certainly played a part in this, but maintenence practices practically determined the engine life.

If the Soviets got only 50 hours from an Allison or Merlin, then I have great respect for a Shvetsov radial that went 180 hours! Maybe they ain't so bad after all. If we ran them on good gasoline and maintained them properly, they might live quite well. I have several friends with Russian Yak-50 / 52's and they get VERY good lifetimes from their Vedeneyev M-14 radial, even though the TBO rating is short. I have one good friend who has been flying his for 14+ years and has had only minor issues that were easily fixed. Nice plane! I love it, at least.

One other observation. I have been a Planes of Fame volunteer since 2006. We have an annual airshow with an average of 30 WWII plane flying in it every year for two days straight (Saturday and Sunday), plus practice days before the airshow. Since 2006, in total, we have had 3 aborts. One was for an engine issue on a Tigercat. One was for a hydraulic failure of a wing fold hose on a Corsair. One was for a flat tire. Think about it. That's a total of about 30 aircaft runing from 1 to 5 flights a day for 2 - 3 days, or about an average of 1,800 flights with 3 aborts. 

Not bad, huh?

Bad engine reliability? I don't think so.


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## Denniss (Jan 17, 2013)

The Jumo 213E's main culprit was the high alt supercharger stage, lack of strategic materials for this highly-stressed components led to many failures/non-functionality/power loss. At least this was reported during testing in late44/early 1945, I have no reliable info about what happened with them in later 45.


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## GregP (Jan 17, 2013)

I believe strongly that the German engines were good engines ... but new planes have issues, almost without exception. Personally, I've seen many "first flights," and have never seen one without a squawk when the first flight was over. Ditto for the second flight. You are usually into the 4th or 5th flight before the plane is OK to fly again after s simple refueling, perhaps even farther into flying.

All the Ta-152's were essentially prototypes thrown together in desperation, and I have no doubt that with development, they would have been stellar contributors to the effort ... but never got the chance and were not produced in large enough numbers before the cessation of hostilities to do anything much for the war effort. There was also no pipeline of Ta-152 spare parts and service manuals. There was very little wrong with the Ta-152 ... but it WAS essentially a prototype pressed into service before it was ready for service as a result of the situation.

Wish we could restore and fly the one at the Smithsonian Museum.


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## parsifal (Jan 18, 2013)

I think the main issue affecting German reliability at the end of the war was the spiralling QA that was bound to lead to increased down times for the aircraft. everything was affected, not just aircraft. Thats not a poor reflection on German engineering, its just an acknowledgement that errors go up as the qulaity goes down, and quality was bound to go down as Germany spiralled out of control and into defeat.


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## GregP (Jan 18, 2013)

Spiraling QA? Please explain.

Perhaps slave labor and the necessity to check EVERYTHING?


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## parsifal (Jan 18, 2013)

spiralling, as in descending uncontrollably

Slave labour would contribute to that. As would the undiscriminating draft that saw highly skilled workers in key industries drafted


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## raumatibeach (Jan 18, 2013)

there's been a distinct lack of Tante ju on this thread since it started, it'd be interesting to hear his thoughts on the subject now.


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## parsifal (Jan 18, 2013)

I predict he will corner one of us, probably the least well informed (that would be me), have a little rant, be extremely rude, deny everything and say while he posted good evidence, we have posted nothing and in particular say the RAF and CW contributed virtually nothing to the allied victory and then stomp off. 

i hope he proves me wrong


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## Aozora (Jan 18, 2013)

parsifal said:


> I predict he will corner one of us, probably the least well informed (that would be me), have a little rant, be extremely rude, deny everything and say while he posted good evidence, we have posted nothing and in particular say the RAF and CW contributed virtually nothing to the allied victory and then stomp off.
> 
> i hope he proves me wrong



'Tis a pity that people get so wound up about events that happened 70 years ago- but then there are those who get wound up about events that may, or may not, have happened 3,000 years ago.  

Now, where were we? Apparently the thesis behind this thread was the terrible record of Allied aero engine reliability which, according to Tante Ju, meant that the average life expectancy or TBO for all engines by 1945 was about 50-60 hours. The Merlin was cited as was the Griffon, Sabre and early Allisons ; funny thing is in Europe these engines (apart from the original Allison engined Mustangs) were using 100/150 grade fuel and high boost on operations and experiencing no problems with unreliability or low TBO:










Merlin 66: 9,268 hrs; over 6,000 hrs by two squadrons alone. (Tante Ju cites worn out Merlin 45s in Russian service.)
Griffon 65: 2,000 hrs; 610 Sqn 1,119 hrs. (Tante Ju cites 1 preliminary test and a post war test with no explanation given as to the circumstances behind the failures...)
Sabre: 2,300 hrs at +11 lbs; reducing to +9 without V-1 threat. (Tante Ju cites 1 test and Eric Brown's experience.)

The Allison V-1710-91, fitted in P-38Ls, was cleared to use the fuel after being run continuously at high boost for 7½ hours (generating 2,000 hp.) 
http://www.wwiiaircraftperformance.org/p-38/Allison_V-1710-91_ENG-57-531-267.pdf

As was the R-2800:





(all WWII Aircraft Performance)


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## parsifal (Jan 18, 2013)

fantastic material, well done


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## 69TA (Jan 18, 2013)

Conflicting information it seems. Have to ask about the origin and autentizy of the three typed documents you presented Aozora?


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## Aozora (Jan 18, 2013)

69TA said:


> Conflicting information it seems. Have to ask about the origin and autentizy of the three typed documents you presented Aozora?



Have to ask?? From your other postings I see you have an attitude problem regarding source material that people have gone to the time, trouble and expense to search out and present on the internet so, no, I am not _compelled_ to answer. Be satisfied that the material is genuine and leave it at that.


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## 69TA (Jan 18, 2013)

Wow. I asked a simple question and you talk about an attitude problem! Maybe you need to look at yourself for a while?

So, do I have to assume You made those piece of papers up or do you have some kind of "source"?


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## Aozora (Jan 18, 2013)

Just for interest, the modifications needed to allow engines to run on 150 grade:

http://www.spitfireperformance.com/JL165-Rolls-Royce.pdf

http://www.wwiiaircraftperformance.org/150grade/cross-channel-ops.jpg

http://www.wwiiaircraftperformance.org/150grade/cti-1659.pdf

and the problems which affected reliability of the V-1650 but not the R-2800-57s in P-47Ms:

http://www.wwiiaircraftperformance.org/150grade/atsce-28march45.pdf


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## 69TA (Jan 18, 2013)

Thankyou


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## Milosh (Jan 18, 2013)

69TA said:


> Wow. I asked a simple question and you talk about an attitude problem! Maybe you need to look at yourself for a while?
> 
> So, do I have to assume You made those piece of papers up or do you have some kind of "source"?



Did you miss the 'WWII Aircraft Performance' source in Post#34?


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## Aozora (Jan 18, 2013)

69TA said:


> Wow. I asked a simple question and you talk about an attitude problem! Maybe you need to look at yourself for a while?
> 
> So, do I have to assume You made those piece of papers up or do you have some kind of "source"?



You can assume anything you like. Members of this forum are entitled to post documents, information and even material from websites _in good faith_, without having to always explain their authenticity or provenance except where there are compelling reasons to believe that the material isn't cocher. A compelling reason could be that you or someone else has seen the original document/material and knows and can prove that the one presented is faked. 

Why Good faith? Because long experience has shown that otherwise interesting and informative threads rapidly deteriorate into bitter, angry arguments over the authenticity of all such material as soon as someone starts questioning the "authenticity and provenance" of someone else's contribution: with the large numbers of knowledgeable and informed people on this forum, altering or presenting a bogus document is risky, because chances are someone will have accessed the original or has material which exposes the fake. You have been warned by a moderator to show more respect -  take his advice.


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## DerAdlerIstGelandet (Jan 18, 2013)

parsifal said:


> I think the main issue affecting German reliability at the end of the war was the spiralling QA that was bound to lead to increased down times for the aircraft. everything was affected, not just aircraft. Thats not a poor reflection on German engineering, its just an acknowledgement that errors go up as the qulaity goes down, and quality was bound to go down as Germany spiralled out of control and into defeat.



I can agree with this. Between slave labor and a lack of skilled labor (With most men of fighting age on the front, this was bound to happen.), you are going to have quality issues. Add that to the fact that they were having to produce large quantities at a very fast rate.



parsifal said:


> spiralling, as in descending uncontrollably
> 
> Slave labour would contribute to that. As would the undiscriminating draft that saw highly skilled workers in key industries drafted



I see we actually agree completely....

Saying the same thing.



parsifal said:


> I predict he will corner one of us, probably the least well informed (that would be me), have a little rant, be extremely rude, deny everything and say while he posted good evidence, we have posted nothing and in particular say the RAF and CW contributed virtually nothing to the allied victory and then stomp off.
> 
> i hope he proves me wrong



Considering he has not done it yet, why make a statement that will certainly put flame on the fire and instigate it? 

Seriously? 

You guys love confrontations. You claim otherwise, but you all do it. Very tiring, very old...



Aozora said:


> Why Good faith? Because *long experience* has shown that otherwise interesting and informative threads rapidly deteriorate into bitter, angry arguments over the authenticity of all such material as soon as someone starts questioning the "authenticity and provenance" of someone else's contribution: with the large numbers of knowledgeable and informed people on this forum, altering or presenting a bogus document is risky, because chances are someone will have accessed the original or has material which exposes the fake. You have been warned by a moderator to show more respect -  take his advice.



Long experience?

How long has your experience on this forum been? Were you a member before with a different username????


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## GregP (Jan 18, 2013)

Getting back to it a little late but parsifal, I agree with you on the spiraling QA. I can tell you from experience that the Japanese radials are VERY reliable and very well made ... at least the Nakajima Sakae 21. Ditto the props that were license-built Hamilton Standard units. The Japanese HAD the license and were legally entitled to make the props. Their own prop designs weren't bad, either. The airframes are well-constructed and well designed using their own criteria. In the USA, we wanted more pilot and aircraft protection, but the Japanese workmanship is very good ... no complaints

The Me / Bf 109 was well made and stout, and whether it be a Spanish Ha-1109 / 1112 or a real Me / Bf 109, the workmanship is excellent. I have seena real Fw 190 and it, too, was well made.

Personally, I haven't see any short-life engines or bad workmanship in the palnes that have survived. Perhaps they bad ones simply didn't survive ... kinda' makes sense to me anyway.

About the infighting in here ... I apologize to anyone I have offended and hope to be more tactful in the future. I confess that when I am attacked, I tend to "fire back." I think most of us do that. Human nature. Sometimes the reply doesn't look so good in the morning and I try to say that when I notice it. I'd MUCH rather discuss and trade information than insults. If I don't agree with a particular point, it is not intended as an insult, just a simple, "I think it might be otherwwise and here is why I think that." Sometimes it doesn't come across quite that way, does it?

At least we all have a common interest in WWII aviation. That makes us all interested in the same subject ... and SHOULD be a source of a desire for interchange, not argument. OK, off my soapbox and back to an Old Frothingslosh Ale, the pale, stale ale with the head on the bottom.


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## DerAdlerIstGelandet (Jan 18, 2013)

GregP said:


> About the infighting in here ... I apologize to anyone I have offended and hope to be more tactful in the future. I confess that when I am attacked, *I tend to "fire back."*



To everyone:

Don't, all it does is stoke the fire and make it worse. It actually ruins threads, because the informative exchanges tend to stop then. Just step back, let us know, and let us Mods take care of it.  Believe it or not, we are watching. Sometimes we miss things and sometimes it might take a while because we have lives outside of the forum as well (shocker huh? ).

As for the above situation, that I commented on above.

Why even say something like that?

1. It has nothing to do with the thread.

2. It only stokes the fire.

3. It is counterproductive. 

4. If anything, all it is doing is instigating a fight. If the said person was not going to fight, he will do so now, because he is offended by the post. 

If anything, it sounds like the person was trying to entice him into a fight. Almost daring him to do so. Why? Are we adults here? Sometimes I wonder?


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## GregP (Jan 19, 2013)

Well said DAG (long name ...) ... perhaps I can emulate your poiltical nature and not "fire back," perhaps not. I'll try ...


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## parsifal (Jan 19, 2013)

> Considering he has not done it yet, why make a statement that will certainly put flame on the fire and instigate it?


He has not shown much restraint to date. ignoring him is like appeasement....hoping he will be nice. My comment was designed to try and make hime think a bit. Wasnt deswigned to inflame him, but Im not prepred to watch him pedal his wares unchecked either. Maybe I should



> Seriously?
> 
> You guys love confrontations. You claim otherwise, but you all do it. Very tiring, very old...



You could not be more wrong in my case. I loathe confrontation. But neither wil i roll over and play nice to some of the attrocious and outrageous things that are said in this place. You have known me for five years now Chris. Im not perfect by a long shot. I have a limit to patience. I admit all that. usually I am the one trying to promote patience and tolerance. And some people absolutely detest that. which is why they come after me so many times.

And no, i am not defying you, or looking to get my head blown off. Im not that silly. If i could get peace in this place, without having to sell my soul for it, trust me i would do it. And that doesnt mean "if i could get my way all the time i would be happy"......


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## Aozora (Jan 19, 2013)

DerAdlerIstGelandet said:


> Long experience?
> 
> How long has your experience on this forum been? Were you a member before with a different username????



Not long on this forum, but I have experienced other forums where threads got nasty once people started the "you tell us the provenance of that document or else" crap, plus I have had a look around here and, while finding found the likes of  this thread , my overall impression is that good faith over posted documents etc is expected - or am I mistaken? And, no I have never been banned from any forum - like parsifal I loath wasting my precious leisure time on stupid, pointless arguments: that said I also value the right to take the time and trouble to post relevant material without having someone else demanding that I prove their authenticity and provenance - As it is please note I usually post my sources. 

You'll have also probably noticed that us "Colonials" (from OZ and NZ) can be blunt and direct - that's just the way we are.


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## Tante Ju (Jan 19, 2013)

Aozora said:


> Apparently the thesis behind this thread was the terrible record of Allied aero engine reliability which,



Made no such statement.



Aozora said:


> according to Tante Ju, meant that the average life expectancy or TBO for all engines by 1945 was about 50-60 hours.



Made no such statement. Most of these engines TBO we do not know, thread is open to find out what was realistic TBO, as said. Western engines did not last more than about 50 hours in Soviet service - fact shown. This may be due to conditions, as shown validly - but then comparison and claim was made with Soviet engines 'relatively poor' TBO times - is it not equally valid that those Soviet engines were operated under same primitive conditions of Eastern Front airfields? Serviced by same mechanics? Filled with same oil? Word disengenious can be equally applied.

Soviet pilot here says for example.
Interview with Vladimir Mukhmediarov

_'I finished the war on Yak-9U with M-107 engine. Its engine life was 50 hours only. There also were a lot of accidents with this airplane. At high power connecting rods would break.'_

So explain me please how 50 hours from Merlin 46 engine is different from 50 hours from M 107 engine. Operated by same skilled mechanics, using same oil, under same conditions.




Aozora said:


> The Merlin was cited as was the Griffon, Sabre and early Allisons ; funny thing is in Europe these engines (apart from the original Allison engined Mustangs) were using 100/150 grade fuel and high boost on operations and experiencing no problems with unreliability or low TBO



Serious engine troubles during testing with high power - shown. An example of Griffon 65 engine lasting between 40-60 hours post war was shown. If you have other _practical_ figures for Griffon engine - show. We all learn...

Also reports made by Allies themselves differ of your opinion.



> 3. At the time the 150 grade fuel was first used all three fighter types listed above were in operational use by this Air Force. Shortly after June 1 P-38 units were re-equipped with P-51 type aircraft so that experience with 150 grade fuel in P-38 aircraft is limited. Gradually, conversion of P-47 outfits to P-51s took place during the Summer and Fall of 1944, and as of approximately 1 November only one P-47 group remained in this Air Force.
> 
> 4. Maintenance difficulties can be summarized as follows:
> 
> ...




Last paragraph is interesting as it cites practical TBO 100 to 180 hours of life with 150 grade fuel (1.5 TEL) before completely destroying valves and requiring engine change.



> Merlin 66: 9,268 hrs; over 6,000 hrs by two squadrons alone. (Tante Ju cites worn out Merlin 45s in Russian service.)
> Griffon 65: 2,000 hrs; 610 Sqn 1,119 hrs. (Tante Ju cites 1 preliminary test and a post war test with no explanation given as to the circumstances behind the failures...)
> Sabre: 2,300 hrs at +11 lbs; reducing to +9 without V-1 threat. (Tante Ju cites 1 test and Eric Brown's experience.)



Soviet Merlin 46s were not worn out. They did not last more than about 50 hours - yes this 50 hours includes familiarisation, as usual. 

Two Squadrons contain about 45-50 aircraft in British practice. 6000 / 50 = 120 hours per plane. What is not known - how many engine changes in meantime?
610 Sqn 1,119 hrs Griffon 65 - about 46 hour per plane in avarage (note post war trial Griffon 65 lasts about this long before engine change is needed...). How many engine changes in meantime?

We must not lose focus on question. What was practical TBO of Western engines under field conditions? Any source Welcome. We all learn.


----------



## Tante Ju (Jan 19, 2013)

First I like to ask for excuse to take so long to answer thread. Different committments..

So, in order.



Jabberwocky said:


> Tante JU, this is very disengenious of you.
> 
> 1. The Merlins in the Russian Spitifres were neither new nor were they maintained to the same standards as in the UK. You have no idea how much time the engines had on them before they went to the Russians.



Source posted shown that they were repaired before sent. In any case, engine life time is not difficult to find - these are precise written in engine log every time (see Griffon source). When Russians say 50 hours, its 50 hours in engine. Its logged in book, simple as that everywhere, since overhaul or built, engine run that much, as recorded everywhere.



Jabberwocky said:


> 2. The V-1710s in Russian P-40s experianced a similar situation



No, 50 hours in book is 50 hours. It seems Russian P-40s Allisons were sensitive to oil condition, dust and maintaince. But no more different than a Yak.

My point is, if you want to dicriminate Allison lifespan because it was Russian mechanics who serviced them, with Russian oil, in Russia conditions, why are some still insists to make comparison with Yakovlev

Allison serviced in good condition vs a Klimov engine serviced in bad conditions? Sure Allison will last longer, it is very correct to point this out by GregP, SR6 and others, but it is everything but a fair comparison, when you want to rule out P-40s in the desert, because they were in harsh conditions (side point - aren't war fighters supposed to be and need to be capable of operated in such conditions?) but at same time it is somehow fair to cite bad TBO for a German/Russian engine with bad supply in the end of the war, for a Russian engines with poor sandy conditions in the Steppe and winter reachinmg -50 Celsius? How fair is it to rule out P-40's cite TBO in North Africa because 'sand is bad for engines you know' but be entirely fine with citing TBO in North Africa for Axis engines. Take for example DB engines in mid war. I am not sure how much pracitcal TBO was, I read about 100-150 hours, but these TBOs were achieved where DB engined planes (109, 110 etc) were deployed to: Africa and Russian steppe most of the time. 

I am sure P-40s lasted longer in nice hangers in mainland USA than Yakovlevs near winter Leningrad, or Spitfires in Crimea. But what is point in such comparisons? 



Jabberwocky said:


> 3. You're using test flights made at high boost with 150 octane engines as representative of regular combat operations. Griffon 65s at +25lbs, Sabre IIs at +11 lbs, Merlins at +25 lbs. Put more stress on these engines and of course the failure rates are going to increase.



I agree at high power, boosted engines etc. failure rates are going to increase. This is whole point of contention - Shortround claims many hundred hours for these later war engines, which seems very very unlikely in view of evidence posted and common sense. But we need to find accurate data to find this out.



> 4. You're pointing to specific examples and then generalising into a trend. This is dangerous territory.



I am not generising. I am collecting information to find out what the truth is. Certainly much less dangerous to do that than simply saying: Western engines were much better. Without any source. Contrary to source. 



> How about some engines in regular service, well maintained by the airforces of the country that built them? How about more than just a few individual examples?



That is exactly what I am hoping to find, as said in first post. Regular engine lifespan, in field. Not manufacturer's selling brochures, with many many disclaimers like R-R papers. 

'Oh our engines last 240.... provided: 1, We only speak 1 in every 3 engine 2, no sand comes near to them 3, high power we note in brochure is rarely used etc.'

Such conditions make TBO figures paper like, as no engine is operated this way in combat aircraft. You cannot compare R-R paper figures with this diclaimers burdened to practical field conditions achievable, yet some do. 



> The R-2800 manual from 1942 suggest a conservative TBO of 350-400 hours. Rolls-Royce suggested a TBO of about 240 hours for the Merlin, but only around 30% of engines actually reached this figure. In service Packard V-1650s had a TBO of 110-180 hours in the Mustang in Nth Africa/Italy.



Can you post these sources please? I am not doubting it, but would like to see.



> An interesting read, if somewhat long, on the Axis History forum, from 2006. Kurfurst and Huck tried exactly this approach and see how far it got them:
> 
> Axis History Forum • Reliability of aircraft engines



Thank you very interesting thread indeed. Lots of noise from everyone, and I am not sure if EKB there did not have an agenda. Still, information is useful, from both parties. I see there were some cases of R-2800 lasting about 700 hours, other time, only 80 hours. Two opposites of extreme ends.




Shortround6 said:


> Rolls was saying in 1939 that a fighter Merlin _could_ go 240 hours and Bomber engine 300 hours. By 1944 they were saying 300 hours and in 1945 360 hours for the fighter engine. Bomber engine life was supposed to be 360 hours in 1944 and 420 hours in 1945. Even if we cut that to 60% for the _average_ that would be 180 hours in 1944 for a fighter engine and 216 hours for a bomber engine. 3 1/2 to 4 times what is being bandied about.



Yes, selling brochure figures.. Rolls was bandied about its engine _could_ go 240 and 420 hours Merlin TBO but it seems _they did not_. In service shown 50 hours they lasted. I am will to see other figures, but none shown since.
Griffon lasted about 50 in Canada. Allied reports show after about 100 hours, valve is destroyed with high TEL fuel.. was Rolls saying 420? Then what? Engine did not last that long in service. 



> Great strides were made in metallurgy and testing during 6 years of war. Post war most of the R&D went into long life rather than power but it seems a bit strange that engines that could only give 50-60 hours of life in 1944/45 could give hundreds of hours of life if not over 1000 hours in post war airliner service. Not so strange if the engines were giving 400-600 hours in the last year of the war.



Show me source that these engines lasted 400-600(!!) hours in the last year of the war practice please.




GregP said:


> This sounds very funny. Since we build Allisons, we have the books and the records of overhaul ... and we talk with and sell to (mostly used to sell to these days) former WWII pilots who have Allison, Merlin, P&W, Wright, etc. - powered aircraft from WWII. For instance, we did the engines for Lefty Gardner and all the flying P-38's except the Red Bull unit.
> 
> According to our information, wartime TBO for the Allison was 250 - 400 hours depending on the dust conditions. Wartime TBO on Merlins was 200 - 300 hours depending on dust conditions. In typical wartime forward area airstrips, typical TBO was 250 hours for both.



Thank you for your posts, very useful, fair and insightful IMHO.

Do you have exact sources of conditions, and could you post them please if I ask?



GregP said:


> Engine reliability depends almost entirely on the use and maintenance of same. Dito the propellers and guns.



Very much agree. IMHO one of most important things to learn and remember from this discussion.


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## Tante Ju (Jan 19, 2013)

Merlin 266 was appearant less reliable than British produced engines. C. Shores: 2nd TAF volume II, page 342.


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## Tante Ju (Jan 19, 2013)

I think this concludes and closes thread part of discussion deciviely. 

V 1650 avarage TBO: 133 - 154 hours for example.






So much for brochure figures...


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## parsifal (Jan 19, 2013)

I stand corrected


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## DerAdlerIstGelandet (Jan 19, 2013)

parsifal said:


> He has not shown much restraint to date. ignoring him is like appeasement....hoping he will be nice. My comment was designed to try and make hime think a bit. Wasnt deswigned to inflame him, but Im not prepred to watch him pedal his wares unchecked either. Maybe I should
> 
> 
> 
> ...



You know I have nothing but respect, but all you are doing is instigating at the moment.

I am sorry but I will not tolerate instigating, just like I wont tolerate rude behavior. Save both those those things for the school lunch room.

How about you let us do out jobs, and not make it more difficult by adding fuel to the fire.


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## Juha (Jan 19, 2013)

Tante Ju said:


> ...Soviet pilot here says for example.
> Interview with Vladimir Mukhmediarov
> 
> _'I finished the war on Yak-9U with M-107 engine. Its engine life was 50 hours only. There also were a lot of accidents with this airplane. At high power connecting rods would break.'_
> ...



Firstly, M-107 is known to have more than its fair share of problems, on Merlin. again, look my message #7, they didn’t have manuals nor anybody to teach them on Merlins.

Juha


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## Tante Ju (Jan 19, 2013)

So how much time Merlin 46 had in British service before requiring overhaul?


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## Juha (Jan 19, 2013)

Tante Ju said:


> So how much time Merlin 46 had in British service before requiring overhaul?



I don't have any good source at hand but from recent messages here:
http://www.ww2aircraft.net/forum/av...s-bf-109-k-4-vs-la-7-vs-yak-3-a-13197-26.html

…
01-15-2013, 06:26 PM Shortround6 

"_…Engine "life" was not a guarantee the engine would make it that long. It was the MAX life of the engine, If the engine actually made it that far it was supposed to be pulled from service at that point and over hauled and NOT run any further. 

Rolls Royce claims that from 1942 on 35% of engines passing though repair organizations had reached their expected service life. They also claim that the average life of the engines passing though repair organizations from 1942 onwards was about 60% of the "nominal" life for the type. 

While the repair organizations couldn't count engines lost in service they were repairing some battle damaged and crash damaged engines._"


http://www.ww2aircraft.net/forum/aviation/western-engine-reliability-35560-2.html

…
01-15-2013, 09:51 PM Shortround6

"_ Rolls was saying in 1939 that a fighter Merlin could go 240 hours and Bomber engine 300 hours. By 1944 they were saying 300 hours and in 1945 360 hours for the fighter engine. Bomber engine life was supposed to be 360 hours in 1944 and 420 hours in 1945. Even if we cut that to 60% for the average that would be 180 hours in 1944 for a fighter engine and 216 hours for a bomber engine. 3 1/2 to 4 times what is being bandied about._"

I would make a quess from 144 hours to 180hours, if I must give one figure I'd say 155 hours on average.

Juha


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## Tante Ju (Jan 19, 2013)

Thank you. It is a pity there is no such report available to us than American above.

Perhaps Guassian curves can be applied to brochure figures, with known 30% success...


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## Shortround6 (Jan 19, 2013)

And so much for the claim of western engines lasting 50-60 hours. 


Companies whose "brochure" figures don't at least come close to reality tend to get little repeat business and go out of business fairly soon. 

The soviet engines, which you seem to think were a close equal, had an awful lot of trouble making 100 hours on test stands. 

on the M-107

"According to the plans, the engine's servicing interval was to be increased to 100hr by 1 May 1941. Series production was to be started, and 2000 M-17s were to be completed by the end of the year. However bench testing revealed vibration, oil leaks which lead to decreased oil pressure, failure of the spark plugs, breakdown of the crankshaft bearings, and leaking of the gas seals. Overheating was also a problem. After some refinement the M-107 successfully passed it's its 50hr test. During 1941 twenty-nine engines were manufactured, these being used for various tests. Series production started in 1942. Certain versions were manufactured until 1948 at factory No. 26 in Ufa. ...... Owing to drawbacks in the design, manufacture was halted several times (in September-December 1945 and April-October 1946). In total 7,902 M-107/VK-107s of different versions were built." 

"*M-107 (M-107P)* The first series-production version of 1941. Power rating 1,300/1,400hp, weight 765kg (1,687lb). This version suffered from failures of con-rods, pistons and crankcases. During 1941-42 686 M-107s were manufactured."

"*M-107A VK-107A)* A 1942 version with variable-incidence blades (Polikovskiy's blades) in the GCS guide vanes. Power rating 1,500/1,600hp, weight 769kg (1,695lb). This engine was in series production form the endo fo 1942 (forty-one were built in 1942). According to the plan, engine service life was to be brought up to 50hr by mid-November 1942, and up to 100hr by the end of the year. In fact, its service life reached 50-60hr. During December 1943-January 1944 the VK-107 was flight tested in a Yak-9U fighter, in April-November 1944 in a Yak-3, and in April1944 in a Pe-21 high speed bomber prototype. The VK-107 remained in production until 1948........In 1946 the reduction gear ratio was changed, the maximum rpm was limited and an additional oil oil pup was fitted ( similar to the one used on the VK-108 ). These modifications allowed the engine to demonstrate a 100hr service life during the check tests."

from Page 143 "Russian Piston Aero Engines" by Vladimir Kotelnikov. 

This has been said before but it seems to _NEED_ repeating. The "brochure figures" are _ maximum_ engine life _*NOT* minimum or guaranteed._

You seem to be implying that the western engine makers were indulging in a dishonest practice. 

What they were saying is that _after_ the "brochure" life figure the chances of inflight failure are going to go up and they are _strongly_ recommending the engine be taken out of service at this point regardless of how well it seems to be running or what points of wear that can be seen without dismantling the engine, show.

Now if you are buying engines for an airline or airforce and Company "A" says the MAX life of their engine is 240 hours and company "B" says 150 hours and company "C" says 100 hours which one are you gong to buy? Maybe company "C" _is_ being more honest and 90% of their engines make it to 100 hours. If 1/3 of company "A"s engines make to 240 hours and the"average life (including prop stikes) is 150 hours how far ahead are you?

If company "A"s engines turn out to have a life under 100 hours Company "A"s reputation will be ruined. Reputation was very important to Western companies because they often "sold" (took deposits on) new engines well before they actually flew. Or airframe makers designed planes to use "new" engines based on promised performance and initial drawings for installations. Stick them with non-performing engines too many times and they won't use the unreliable company's engines in future designs.


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## Tante Ju (Jan 19, 2013)

Shortround6 said:


> And so much for the claim of western engines lasting 50-60 hours.



They did last 50-60 hours in Soviet service. Same as VK 107 - which was a poor engine no doubt for reliability.

Note that even in much more favourable conditions than Soviet front, V-1650 (Merlin) did not seem to last more on avarage than 130 hours. The vast majority, say 80-90% was performed at low cruise ratings, this certainly helped to prolong engine life - 8 hour sorties at low powers escorting bombers did not put nearly big as strain as Soviet practice of flying max. 1 hour sorties near frontline as fast as possible. 

BTW Merlin also had 'awful lot of trouble' completing 100 hour tests on bench. Well known from history.

Griffon did last 40-60 hours in post war Canadian service it seems.

I am curious how long Sabre lasted. I think 40 would be very generous assumption, given plague history of engine.

And as much as you like kick Soviet engines for developing about 50% of their brochure figures in service, I wonder how that compares to Allisons 700+ hour claims vs. 150-180 hours in practice..

PW engines seems best, though statistics may be somewhat unfair as many had duel (fighter-bomber) applications, and bomber use tends to improve statistics.


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## Aozora (Jan 19, 2013)

Tante Ju said:


> Soviet pilot here says for example.
> Interview with Vladimir Mukhmediarov
> 
> _'I finished the war on Yak-9U with M-107 engine. Its engine life was 50 hours only. There also were a lot of accidents with this airplane. At high power connecting rods would break.'_
> ...



You have no idea of the condition, the relative skills of the mechanics, or what type of oil or fuel was being fed to the Merlins; also you seem to be forgetting, there were no servicing manuals for the Spitfires or their engines...







Plus you obviously haven't read your own extracts so let me refresh your memory...



> According to the account of Nikolay Isaenko, having begun to fight in August 1943 in equipment that had been worn in the process of training and ferrying,_ the 821st IAP entered combat work with already “problem” engines.
> _
> Taking into account that the fighter was an imported item, which began to experience shortages of spare parts for various assemblies from the beginning of use and especially of combat work, it was unavoidable that these shortages would have an impact on the material condition of the aircraft. Spare parts were in short supply for the Merlin, for the Rotol propellers, for coolant and oil radiators, wheels, and instruments.



Also noted you haven't mentioned the fact that another Soviet pilot thought the reliability of the Merlins in the Hurricane was okay.



> A. S. What about the English engine, they say it was unreliable?
> 
> N. G. It was a good engine, powerful and sufficiently reliable. The engine worked very clean. It had exhaust stacks and flame suppressors, mounted like mufflers. This was very helpful because it prevented the pilot from being blinded. In this regard our own aircraft were significantly deficient.



This was the more complex Merlin XX with a two-speed supercharger.



Tante Ju said:


> Serious engine troubles during testing with high power - shown. An example of Griffon 65 engine lasting between 40-60 hours post war was shown. If you have other _practical_ figures for Griffon engine - show. We all learn...








So, let's have a look at that extract from a Canadian report shall we? First engine 5672/590356 removed due to rough running and vibration, no cause shown, so that proves nothing - it was not engine failure: note: Carburettor serial No. RGA 194

Next engine 1752/334548 installed - Carburettor serial No. RGA 231. engine failed, cause noted in Sec. 201 - not shown by Tante Ju. Why did that engine fail? Was it related to damage caused by the vibrations from the propeller removed during the first stages? Do you have Sec. 201? Show us so we can all learn.

First engine 5672/590356 reinstalled with same carburettor as second, serial No. RGA 231, indicating first problems were carby related, not engine. Test session ended. 
Some questions, to put this extract from a report, and the report itself, into context:
*What was the purpose of the tests? Was it the engines being tested or the airframe?
*What mark of Griffon was being tested?
*What were the concluding remarks of the test? I have to assume that if the conclusion stated that the Griffon was unreliable and showing a tendency to fail at low hours that conclusion would have been added to this thread.

Without knowing what the tests were for and what the concluding remarks were, plus the comment on the total engine failure there is no context, therefore using this to prove poor reliability is a waste of time.

As for this:


> 4.3 Spitfire XIV (Griffon 65)
> Spitfire R.B.176, as received from Squadron, was operating at +19 lb./sq.in. boost and 2,750 r.p.m. (Griffon 65; 5-bladed Rotol propeller). It had a circular external rear view mirror with hemispherical fairing; no ice-guard on the air intake; a whip type aerial behind the hood; a radio mast projecting from the lower surface of the wing forward of the starboard aileron; another mast set in a fairing under the fuselage; small type bulges over the 20 m.m. cannon and the cannon stubs faired; the machine gun ports in the leading edge sealed. The 30 gal. auxiliary fuel tank (slipper type) was removed for the purpose of the tests.
> The paintwork was in poor condition. Parts of the leading edge and inboard surfaces of the wings were very badly chipped and scored. The leading edge was stripped of paint and repainted. The rest of the aircraft was rubbed down only.
> The engine was then modified to give +25 lb./sq.in. boost and one flight was made. Only two level speed measurements were obtained, as the engine became suddenly rough after about two minutes of the high boost on each level. Subsequent inspection showed that a blow back had occurred, damaging the air intake. The reduction gear was also found to be cracked and no further tests could be made with this engine.



*How many hours did the Griffon have on it before being tested at the RAE? Doesn't say.
*How often had it been put under strain possibly chasing V-1s? No mention of the engine's service life.
*Paintwork in poor condition meaning this aircraft had seen considerable service and possibly been through some debris from V-1s?
Engine blowing back "popping" into air intake? Several possible causes, not all directly engine related see below:





Engines vibrating or not delivering power:








From:








Tante Ju said:


> Also reports made by Allies themselves differ of your opinion.



And, clearly, from yours, http://www.ww2aircraft.net/forum/av...4-vs-la-7-vs-yak-3-a-13197-26.html#post975423



Tante Ju said:


> Last paragraph is interesting as it cites practical TBO 100 to 180 hours of life with 150 grade fuel (1.5 TEL) before completely destroying valves and requiring engine change.



And far higher than the 50 hours you assert here...http://www.ww2aircraft.net/forum/av...4-vs-la-7-vs-yak-3-a-13197-26.html#post975423 

Not forgetting that is at high boost pressures using 150 grade fuel.



Tante Ju said:


> Soviet Merlin 46s were not worn out. They did not last more than about 50 hours - yes this 50 hours includes familiarisation, as usual.



So prove it, show us all solid documented evidence that this was so, apart from your opinion.



Tante Ju said:


> Two Squadrons contain about 45-50 aircraft in British practice. 6000 / 50 = 120 hours per plane. What is not known - how many engine changes in meantime?
> 610 Sqn 1,119 hrs Griffon 65 - about 46 hour per plane in avarage (note post war trial Griffon 65 lasts about this long before engine change is needed...). How many engine changes in meantime?



Had there been problems leading to a higher than average incidence of engine failure that would surely have been mentioned. The report doesn't mention a high incidence of engine changes.


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## Aozora (Jan 19, 2013)

Tante Ju said:


> BTW Merlin also had 'awful lot of trouble' completing 100 hour tests on bench. Well known from history.



Well then, provide some evidence that this blanket assertion applies to all Merlins, and not just the early developmental prototypes.



Tante Ju said:


> I am curious how long Sabre lasted. I think 40 would be very generous assumption, given plague history of engine.



Up to you to prove - there's no doubt Sabres were thoroughly unreliable until Bristol stepped in and helped Napier with the sleeve valves, after which there were no major problems.


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## DerAdlerIstGelandet (Jan 19, 2013)

Aozora said:


> Not long on this forum, but I have experienced other forums where threads got nasty once people started the "you tell us the provenance of that document or else" crap, plus I have had a look around here and, while finding found the likes of  this thread , my overall impression is that good faith over posted documents etc is expected - or am I mistaken? And, no I have never been banned from any forum - like parsifal I loath wasting my precious leisure time on stupid, pointless arguments: that said I also value the right to take the time and trouble to post relevant material without having someone else demanding that I prove their authenticity and provenance - As it is please note I usually post my sources.
> 
> You'll have also probably noticed that us "Colonials" (from OZ and NZ) can be blunt and direct - that's just the way we are.



You also will have possibly noticed that we Mods are getting sick and tired of all the stupid bickering by people that want to do "He said, she said BS" internet fights and arguments. 

Instead of calling people out, let us Mods do our job. If you have a problem with someone, instead of stoking the fire, let us know, and we will assess it and handle it. 

One can debate with pointless name calling and rudeness, and instigating fights. Even if you think that something is pointless. I am not taking sides, I don't care if you are like parsifal or not. Parsifal knows that I have nothing but respect for him, and that we actually see eye to eye on most topics. I have defended him and taken his side enough for him to know this, but that does not mean I am not sick and tired of it. 

So don't start doing it as well. 

Is that okay?


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## Shortround6 (Jan 19, 2013)

Actually the Sabre was a troublesome engine until almost the end of the war (if not forever?). 

Fair is fair.

Little has been said about the Hercules though. Not sure how the war time models were but the post war versions certainly racked up some impressive TBOs.


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## GregP (Jan 20, 2013)

Hi Tante Ju,

We have a museum flying event on the first Saturday of every month. We have had these events for 40+ years. Since MOST of our aircraft are fighters, the vast majority of our events are about fighters, with appropriate speakers. We fly American, British, Russian, and Japanese engines, with the occasional French engine thrown in (we even have an Antonov AN-2). We fly Allison V-1710's, Merlins, R-1820's, R-1830's, R-2600's, R-2800's, a Nakajima Sakae 21, the Bristol Centaurus, the GE-IA, the GE-I16, the J33 and several others up to and including the J-47, together with a few smaller engines.

The fighter pilots who give talks on a very ragular basis tell us of their experiences with the fighters. They don't spend a lot of time on conditions since most of the visitors attending these events aren't really interesed in conditions ... they want combat stories. Almost none of the pilots who have spoken over the years had bad things to say about the engines or aircraft. Most of the sudden stoppages were due to combat damage.

So, a relatively large cross section of WWII pilots who flew combat LIKE the Allison, the Merlin, the DB 601/3/5, and the various radials. The Japanese pilots liked their radials, but not their inlines. The Germans liked their engines, too, both radial (BMW 801's, etc) and inline (DB 601/3/5 and Jumos). The conditions on the Russian Front are responsible for the lousy engine life in Russia. They didn't experience that elsewhere except in very dusty conditions (think Malta and Coral dust in an aircraft not running an air cleaner at all).

While all these engines don't require excessive maintenance, they DO require maintenance. Ask FlyboyJ or DerAdlerIstGelandet (how the hell do you pronounce that?). They know. If you don't DO it, they will probably all fail at about 40 - 80 hours. You have to do the maintenance to keep them running well. Our own Allison V-1710's with 1,200 hours on them would never make it that far without normal maintenance. You have to change oil, oil and fuel filters, plugs, set valves, torque cylinders on the Merlins, and a host of other small but vital maintenence actions. I am working right now at changing the lower oil lines on a P-47's R-2800. They haven't failed but are due to be changed. If you don't, and if they then fail, the fault is YOURS, not the engine's.

Sorry, the Allisons and Merlins that died at 50 hours were killed by unskilled users and maintainers; they weren't bad engines. Ditto for DB, BMW, Nakajima, Mitsubishi, Alfa Romeo, Junkers, etc.

I hate to make the obvious point, but bad engines usually never made it into production due to their excessive failure rate. The exception was the R-3350, which was awful when introduced, but turned into the most reliable big radial ever after the war due to developed operating and maintenance procedures.


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## wuzak (Jan 20, 2013)

GregP said:


> DerAdlerIstGelandet (how the hell do you pronounce that?).



Boss.....





GregP said:


> I hate to make the obvious point, but bad engines usually never made it into production due to their excessive failure rate. The exception was the R-3350, which was awful when introduced, but turned into the most reliable big radial ever after the war due to developed operating and maintenance procedures.



Vulture. Sabre. Db 606 (or was that more specific to the installation in the He 177?).


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## Aozora (Jan 20, 2013)

wuzak said:


> Vulture. Sabre. Db 606 (or was that more specific to the installation in the He 177?).



I don't know if I'd quite lump the Sabre in with the Vulture or DB 606/610, considering the numbers of Typhoon and Tempest pilots who put their lives on the line behind the beast. That said they did initially have a very short service life:





The Vulture had inherent design flaws, in particular the star-shaped conrod assemblies, and the use of which Rolls-Royce weren't able to deal with until too late:











The revised design, too late:








(Robert Kirby; Avro Manchester: The Legend Behind the Lancaster. Midland, 1995 83-84, 103-104) Avro Manchester: The Legend Behind the Lancaster: Amazon.co.uk: Robert Kirby: Books (excellent book


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## wuzak (Jan 20, 2013)

Aozora said:


> I don't know if I'd quite lump the Sabre in with the Vulture or DB 606/610, considering the numbers of Typhoon and Tempest pilots who put their lives on the line behind the beast.



I would, in that the Sabre was in production before it was quite ready.


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## Aozora (Jan 20, 2013)

wuzak said:


> I would, in that the Sabre was in production before it was quite ready.



Definitely from that perspective - an average life of 25 hours was lamentable.


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## Marcel (Jan 20, 2013)

GregP said:


> Sorry, the Allisons and Merlins that died at 50 hours were killed by unskilled users and maintainers; they weren't bad engines. Ditto for DB, BMW, Nakajima, Mitsubishi, Alfa Romeo, Junkers, etc.


 
Not knowing enough to participate in this technical discussion, I still might make an observation? Seem to me when reading Tante Ju's comments that he is actually not claiming that these were bad engines, although the title of the thread suggests otherwise? His claim seems to me that the Russian engines were not so bad as everyone thinks. The short lifespan of these engines seem to be caused by the conditions and lack of maintenance in Russia. And he tries to prove that by showing that, western engines did not do better under the same conditions. I think you all agree that the maintenance in Russia left a lot to be desired. in this case comparing western engines under western conditions and Russian engines under Russian conditions seems to be non-informative in my eyes. So I'm wondering what the heated discussion is all about. 

But I'm not a native English speaker and I usually miss the subtilities in the language. And I also have not followed the discussion that triggered this thread. So I might have understood it wrongly.


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## meatloaf109 (Jan 20, 2013)

GregP said:


> DerAdlerIstGelandet (how the hell do you pronounce that?).


The Eagle Has Landed in english. But to be on the safe side call him "Sir". Same with FLYBOYJ.


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## Denniss (Jan 20, 2013)

DB 606/610 were not unreliable but the engine installation in the He 177 led to many problems - maintenance was a nightmare. Due to tight installation the mechanics could not access all vital parts without a heavy crane to dismount the engine.


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## parsifal (Jan 20, 2013)

Tante I want to congratulate you on your excellent response. Well done. You proved me wrong, and Im happy. 

Thats the good news. The bad news is that I still am not convinced. Others have taken you to task on that. You dont need me to spoil your day.


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## tomo pauk (Jan 20, 2013)

I must thank to Aozora in providing the excerpts.

Agreed with Dennis, at least DB-610 developed no known issues/problems.


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## Shortround6 (Jan 20, 2013)

We maybe having language problems. I speak only English (and maybe not to well at that  so I am not sure how well somethings translate. 

When dealing with engines were have two characteristics we are dealing with. 

_Durability_

_Reliability_

Durability is how long the engine (or major parts of it) will last.

Reliability is how likely the engine is to complete a given mission or, upon being called to start-up, can under take a mission on a given day. 

For instance the DB 610 may have just as _durable_ as the DB 605 but it's reliability would be lower, in part just because you have twice as many parts, in part because servicing is harder, in part because heat in the installation may affect smaller accessory parts. 

Many engines had problems with magnetos, carburetors, pumps and other bits and pieces stuck on the out side that affected over all reliability. 

Some other engines were known for putting rods through the side of the block or having the gear case fail and loosing their propellers well before their rated service life was up. One might say that in those cases durability did affect reliability  

One also has to be careful in using some of those General over haul charts. To take the Allison engine, which was pretty well built chunk of engine overall( and it did change quite a bit over the years). In Europe and the MTO in US service it was used in 3 aircraft, the P-40, the P-39, and the P-38. The First wide spread combat use was in North Africa with the "F" series engines. Lots of sand and dirt, How much over boosting on the P-40s. P-38s had [/I] reliability problems due to the turbo installation AND had durability problems due to the turbo. Wartime pilots (in many air forces) didn't really understand how their engines worked. They were told (instructed) to do such and such and they did it. P-38 pilots for a long time were being "instructed" to fly (cruise) a certain way which was against the recommendations of both Allison and Lockheed. They were being instructed to fly/cruise at high rpm and low boost. Which is sort of like driving a 4 speed car in 3rd gear on the highway. It will do it, it will do it for hours or thousands of miles but it uses more fuel and _will_ wear out the engine quicker. You also have a strange fact with the P-38s, If the pilots abuse an engine in a P-40 and blow it up they usually don't get back to base to have the engine replace/sent for overhaul. P-38s could blow up one engine and bring it back so it showed up in the statistics.

The overhaul statistics are good information but they show the engines that made it to the overhaul facilities. They may or may not give the reasons for the engine going to the overhaul facility. In the case of the Merlins and R-R it was the average of _ALL_ engines going threw the repair organization which includes battle damage and crash damage (prop strikes). If you get in one engine with 10 hours and a prop strike and one engine with 300 hours and just worn out/hit service life limit you have a 155 hour average. Rolls-Royce and the repair organization had had worked out a particular repair for Merlins that had cracked the main gear case due to a prop strike or crash. The cracks were welded and a steel strut was added that ran from the top rear of the gear case on an angle down and back to the crankcase (not cylinder blocks). Since the engine _had_ to be torn down for inspection it only made sense to do the small amount of extra work to do a complete overhaul.
Engines could be sent for overhaul for a variety of reasons. Low oil pressure (which changing the pump/s doesn't cure), metal showing up in the oil filters/strainers are two main ones. Some engines didn't tolerate over revving very well. "Power" diving had the potential to wreck engines. The Merlin was rated at 3600rpm in a dive but at part throttle (1/3 or 1/4?). Using large throttle openings while diving could wreck the engine. A malfunctioning propeller could also affect the life of the engine. Some propellers didn't change pitch when they were supposed to (or did after a delay) and allowed the engine to over rev. 
Some of the difference between bomber and fighter engines may be due to factors like these. While bomber engines didn't have to put up with over boost much or lots of _large_ throttle changes, they often had to put out full take-off power for 4-5 minutes to get off the ground and get the gear up followed by 20-30 minutes at max climb power to reach altitude. Fighters, unless carrying large external stores, could often throttle back a bit sooner.


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## DerAdlerIstGelandet (Jan 20, 2013)

meatloaf109 said:


> The Eagle Has Landed in english. *But to be on the safe side call him "Sir".* Same with FLYBOYJ.



Not necessary. Don't say such things, some might believe you. 



parsifal said:


> Tante I want to congratulate you on your excellent response. Well done. You proved me wrong, and Im happy.
> 
> Thats the good news. The bad news is that I still am not convinced. Others have taken you to task on that. You dont need me to spoil your day.



And you keep picking...


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## GregP (Jan 20, 2013)

Some great replies in there since my last post.

Marcel, I believe the Soviet engines WERE pretty good, expecially considering the conditions and skill of the maintainers and pilots using them. I have many stories of how they were able to operate, including building a fire under the engine after the gas and oil had been drained to keep it warm! ... and in a wooden aircraft! As I said some time before, I have several friends with Vedeneyev M-14 radials that absolutrly love them ... and they seem to last very well. Your remarks are interesting and give pause for thought.

Same for Shortround's excellent post. Relaibility and durability ARE two different things, and many people never realize it.

I am well aware of the Sabre's shortcomings and the same for some of the German experiments, but I didn't bring them up since I already had an example. I believe that there were never very many He 177's built (600 total before they realized it was a turkey?) compared with 10,000 - 20,000 of other, better designes and over 30,000 Me / Bf 109's. Still, I will admit that definitely qualifies as production of a powerplant that was hopeless. And they DID finally "fix" the Sabre. If there was one around today, I'd probably not opt to fly it if the opportunity became available simply because I'd have no way of knowing if was one of the "fixed" units or not. The knowledge has withered away on the Sabre to the point where, world-wide, I am not aware of one that is runnable. Perhaps there IS one or even several, but they aren't exactly wide-spread and I don't know of a shop that claims to be able to overhaul one.

One the other hand, we regularly fly the Merlins, Allisons, various radials, and there are enough DB 601/3/5's around that they CAN be overhauled and made to run. Finding a VDM propeller is another story ...

So, I suppose my point is that the reliable and durable engines survive to be flown today, and some of these were being touted as 50-hour engines. I beg to differ on that score, not entirely (there well might have been 50-hour Allisons and Merlins, but not many) but as a general statement. The discussion is very interesting with good information being exchanged.


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## meatloaf109 (Jan 20, 2013)

DerAdlerIstGelandet said:


> Not necessary. Don't say such things, some might believe you.


Yes, Sir!


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## Juha (Jan 20, 2013)

Marcel said:


> Not knowing enough to participate in this technical discussion, I still might make an observation? Seem to me when reading Tante Ju's comments that he is actually not claiming that these were bad engines, although the title of the thread suggests otherwise? His claim seems to me that the Russian engines were not so bad as everyone thinks. The short lifespan of these engines seem to be caused by the conditions and lack of maintenance in Russia. And he tries to prove that by showing that, western engines did not do better under the same conditions. I think you all agree that the maintenance in Russia left a lot to be desired. in this case comparing western engines under western conditions and Russian engines under Russian conditions seems to be non-informative in my eyes. So I'm wondering what the heated discussion is all about.
> 
> But I'm not a native English speaker and I usually miss the subtilities in the language. And I also have not followed the discussion that triggered this thread. So I might have understood it wrongly.



I frankly doubt that, if one wants to make a reasonable comparison between the reliability of Soviet and Western aeroengines, IMHO right way would be compare e.g M-105 series engines to DB 601/605 series and RR Merlins, all main V-12 inline engines of respective nations. Compare M-107 known to have been problematic and Merlins which were maintaned by mechanics who didn't have access to manuals and not even had somebody who had previous knowledge of the engine to give advise. And that in a regiments which previous a/c had been powered by an aircooled radial. And then draw a sweeping conclusion on average reliability of Merlin in front-line use from that.


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## Juha (Jan 20, 2013)

IMHO Sabre was reasonable reliable engine once Bristol was persuaded to help Napier with sleeve valves and Napier was put under control of the EE Group and AM finally was ready to accept paper gaskets.

Juha


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## Shortround6 (Jan 20, 2013)

The Russian engines may have been better than we give them credit for. However there is another aspect of engine durability/reliability that comes into play. 

Quality of construction/quality control. 

There has been a lot of ink and internet band width used up trying to claim that Rolls (or Ford of England or???) made better engines than Packard or vise versa. 

This a totally different subject than faulty ( or perhaps underdeveloped?) design. faulty design can be parts (Con-rods, Crankshafts, crankcases, etc) to small/weak to handle the expected loads. It can be other things like inadequate cooling in spots, like one bearing running hotter than others because of a difference in oil flow. 

Quality of construction/quality control can be the fit and finish of parts. How well do pistons match each other in weight, How well are they matched to the bores. How well do the bearings fit. How good is the finish on the bearing surfaces. How well are things like con-rods polished. A polished con-rod will often last much longer than one with a few surface imperfections because fatigue cracks often start at the surface imperfections. 

The quality of the work force and inspectors plays a big part here as does the provision of test/inspection equipment. Quality control changed for some nations more than others as the war went on, some got better, some got worse. Raw material shortages can also come into play. Japanese may have plagued by this. If you are short of certain elements/alloys that go into a design substitutes are often tried, sometimes they work and sometimes they don't. Or they work but not as long. Material shortages _may_ come and go. 

Peace time built engines *should* be more reliable even if of the same design. material shortages should no longer be a consideration. The push for maximum production is no longer there. In some countries during the war too many engine failures could get the plant managers shot or sent to the front as infantrymen. However failing to meet assigned production quotas could result in the same fate. A fine line between keeping up quality or quantity. 

High power aircraft engines were on the very cutting edge of technology of the time. Time and again they introduced new alloys, new heat or surface treatments, new manufacturing techniques. Sometimes it took a while for some of this new technology to get passed around. Post war engines benefited from much of the development done during the war.


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## DerAdlerIstGelandet (Jan 20, 2013)

meatloaf109 said:


> Yes, Sir!



Arse...


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## tyrodtom (Jan 20, 2013)

I remember when I called the drill sergant "sir" when I was going thru Army Basic, he said " Don't call me sir, my parents were married". He said this with the 2nd LT. training officer within earshot.
At the time I didn't think it'd be very smart to ask him if his parents were married to each other.

In that era, you only used sir when speaking with officers, and it's stuck with me. It still get's under my skin a little if someone addresses me as "sir".


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## Aozora (Jan 20, 2013)

Just a word on TBO (Time Between Overhaul), which has been used quite a bit (and this kind of works in with Shortround's postings); an engine which has reached TBO isn't necessarily in need of an overhaul:


_View: https://www.youtube.com/watch?v=tyJiAdMD8AM_


_View: https://www.youtube.com/watch?v=nv2x6RQxFDo_


_View: https://www.youtube.com/watch?v=5__b34cEORE_


_View: https://www.youtube.com/watch?v=ZUnun6QmVXk_


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