Western engine reliability

[Tante Ju]

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."

Adjustment of the engine itself, according to the testimony of specialists, was simple. The qualities that the pilots liked, and which were very important in aerial combat—transition to various regimes of power of the Merlin were smooth. The engine had good acceleration—it is obvious that this quality substantially assisted Spitfire pilots in combat with Messerschmitts, which thanks to the power of the Daimler-Benz engine had good speed dynamics.

A negative quality of the Merlin was the absence of a two-speed supercharger, which reduced the ceiling [altitude range] of the engine. The engine broke down after 50–60 hours of use, after which it was necessary to change out the piston rings, along with other assemblies: hydraulic systems, fuel pumps, and air compressor. The water pump was very complex in its design and, as a rule, broke during use. "There were cases in the process of use of breakage of piston rings, broken connecting rods, the consequences of the leak of coolant in places where the cylinder sleeves were press-fitted. There is no method for starting the engine from a wheeled vehicle", says a summary of technicians of the 57th GIAP.

Over the course of May 1943, three engines were removed from use. One Merlin-45, because of piston-ring breakage, suffered a failure of pistons and cylinders. The second failed because of high temperature—the oil temperature reached 100–110° C, and the coolant 120–125° C. The same high oil and coolant temperatures also occasioned the removal of a Merlin-46 engine. The observation was made: "shaking [vibration], engine smoking, poor power, result of worn piston rings." At the moment of failure, all three engines had approximately 40–60 hours of use. These engine failures became one of the primary causes of subsequent misfortune in the utilization of aircraft in 57th GIAP and 821st IAP. Appendix 6 presents the average intensity of aircraft sorties—36.1 for one serviceable aircraft, of which there were on average not more than 12. (In the same table, 16th GIAP had 18 aircraft and 42d GIAP had 26 aircraft.) The flight time for one serviceable aircraft was 43.4 hours. 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. For this reason, a portion of the aircraft had to be rebuilt using parts from others. According to summaries, the greatest deficit was in wooden propellers. Over the course of May, the regiment did not receive a single spare propeller, despite the fact that they failed the most often. "Wooden propeller blades fail at airfields that have gravel [surfaces]... A large number of dents prevent proper use of the propellers", it says in the summary.

Source. Spitfires over the Kuban

 

[Tante Ju]

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.

These first Allisons did not deliver even one-half of the recommended engine hours. 50 hours was its limit, and frequently less. Normally 10—15 sorties if they were in combat. They seized, the bearings melted; this happened to me once. I sat out for a while with no engine. They monitored these engines closely. As soon as any metal showed up in the oil, they changed out the engine. The supply of replacement engines was plentiful, but it was not always possible to get delivery of them. Sometimes they brought them in on an Li-2 [Soviet-built C-47], four in a load, such was the demand for new power plants. But just the same, despite our best efforts, there were seizures. True, this engine did not "throw" connecting rods, at least this never happened to us. On type-5 and later models the engines were more powerful and reliable.

Now regarding power settings. In principle the RPMs were regulated by a conventional throttle. In the Cobras there were two regimes of throttle operation, "normal" and "war emergency", which was characterized by increased manifold pressure. The throttle quadrant was mounted in the [left side of the] cockpit and the pilot controlled it. The "war emergency" regime had a lever position that we called "51 inches and 57 inches of boost". If we were flying on Soviet B-95 fuel, then "war emergency power" was set at 51 inches. If we were using American B-100 fuel, then "war emergency power" was set at 57inches. Although it was mounted in the cockpit, on the throttle quadrant, the pilot did not adjust this setting. The position of the "war emergency power" selector was controlled by a piece of wire that could be broken easily with greater forward pressure on the throttle quadrant.

One time I sensed a lack of power (I needed to get ahead of a German) and I thought, "The hell with it"! I broke the wire and selected "57". Then I experienced what "57" meant! My airplane leapt forward! The Germans spotted me from above and dove immediately, which was what we wanted.

American gasoline was better than ours. Not more powerful, but better. The anti-detonation qualities of our gasoline came from the addition of tetraethyl lead. After every two or three flights the engine mechanic had to clean the lead from our spark plugs. If he waited too long, a lead droplet would form between the electrodes. But this was not a special problem. Normally our spark plugs were quickly cleaned after every sortie. But with the American gasoline, this did not happen. Either they used higher octane to begin with and added less lead or they raised the octane rating with benzol [another additive]. Perhaps it was just the benzol. Because our gasoline was pink in color and the American gasoline was dark blue.

Incidentally, the Allison "made metal" on any gasoline. Realistically the Allison engine began to live up to its full 100 hours of use only in 1944. These engines came in the Q-25-30. But by this time the intensity of air combat had already fallen somewhat, and the primary distinction of these types was the perceptible decrease in power output. Therefore we removed the wing machine guns. They were heavy [one Browning .50 caliber under each wing], slowed the airplane down, and their recoil was felt in combat.

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

 

[Tante Ju]

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.

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.

 

[Tante Ju]

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.

The effect of improving the condition of the paintwork was measured on Tempest JN.783. This was a standard series I fighter aircraft (four 20 m.m. cannon projecting from the leading edge of the wing). The gun muzzles were sealed. There were blisters on top of the wings over each gun. A debris guard was fitted in the air intake.

The paintwork was in fairly poor condition. It was badly chipped along the leading edge of the wing. The wing surface was stripped for a distance of about 2 ft. back from the leading edge and repainted. The rest of the wing and aircraft surfaces were rubbed down only. The aircraft could have been maintained in this final condition without any great difficulty under squadron conditions.

During the test, the engine in this aircraft was giving only +7 ˝ lb./sq.in. boost and as a defect was subsequently found, J.N.738 was rejected for further tests at higher boost.

This aircraft was replaced by Tempest J.N.735 but, during the first flight, the engine caught fire and the aircraft had to be abandoned.

The effect of increasing the boost pressure was measured on Tempest J.N.763. This aircraft was a standard series I fighter aircraft, similar in quality of finish and in external equipment to J.N.738, described above, except that it did not possess a debris guard.

A new boost cam and capsule were fitted allowing an increase in boost pressure to +11 lb./sq.in. The 150 octane fuel was used.

Flights were made at +9, +10 and +10 ˝ lb./sq.in. boost respectively (3,700 r.p.m.) One flight at +11 lb./sq.in. boost was made but engine trouble was experienced and in the subsequent inspection, parts of the pistons and piston rings were found in the oil filters.

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 third run was made at 7,000 ft, at which height only +8 1/2 lb boost was obtainable at full throttle, and after 3 1/2 min I detected a slight smell of burning coming from the floor of the cockpit. A quick check of the negine instruments showed zero oil pressure and oil temperature, with the coolant temperature 108 C. Since the engine had never faltered I suspected oil gauge failures, but throttled back to -4 lb boost and 2,900 rpm and asked for an emergency homing on the R/T, which I was given. I flew on this course at the same height and low engine settings as before until I thought I was near base, when I decided to descend through the solid cloud (top 5,800 ft and base 2,300 ft). On entering the darkness of the cloud I could see the whole top engine cowling glowing hot between the two sets of exhausts, although this had been unapparent to me in the bright sunshine. However, the engine was still running, so I continued the descent, but before I broke cloud the engine began to misfire badly and the propeller started to overspeed. I immediately pulled the constant-speed lever back to the fully coarse stop, but the revs. reached 4,200 and then there was a loud bang in the engine, followed by a spray of oil which covered the windscreen.

In order to see out I had to undo my safety harness and peer round the opaque windscreen. The propeller had seized solid, and the fire under the cowling had now burst into intense white flames which were also creeping into the cockpit through the floor near the rudder pedals, so the underside must have been well alight too, a fact which was later confirmed by ground witnesses. The heat round my feet hastened my decision to abandon the aircraft.

I removed my helmet and trimmed the aircraft for level flight at 1,600 ft and 170 mph, then stood up on the seat and put my left leg over the port side of the cockpit before reaching inside to pull the stick hard over towards me, so that when the aircraft reached an angle of bank of about 60 degress I could kick myself free. The altimeter had read 1,200 ft when I glanced at it as I grabbed the control column spadegrip. When I pulled the parachute ripcord I could see I was heading for open fields, but I was hardly ready for the touchdown because I was watching the Tempest, which hit the ground and exploded some 200 yards from a small pond into which I found myself deposited. From this point the drama gave away to sheer comedy.

The pond that received my unexpected visit was shallow and not particularly salubrious, so I moved as smartly as I could to its edge, only to find myself face to face with the only other occupant of the field - a very large unfriendly looking black bull. As I moved a few steps nearer it lowered its head and snorted through its ringed nose. Discretion being the better part of valour, I did a smart about turn and headed for the opposite side of the pond, but I had just got there when I realised that I had bbeb beaten to it by my bovine acquaintance, who was determined to provide a personal reception service. There was nothing for it but to await deliverance in some form or another. Alerted by the exploding aircraft, the local fire brigade and police soon arrived, but baulked at the sight of the bull. There was then a hiatus while the police found the owner, who appeared with a short rope which he passed through the animal´s nose ring and then gently led him off like a poodle. I may be wrong, but I could swear that the bull winked at me as he departed.

The Hawker Tempest Page

 

[parsifal]

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.

 

[Jack_Hill]

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.

 

[Juha]

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."

 

[Shortround6]

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.

 

[davparlr]

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

 

[DerAdlerIstGelandet]

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.

 

[bobbysocks]

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

 

[parsifal]

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.

 

[Jack_Hill]

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 ?

 

[Jabberwocky]

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

 

[CobberKane]

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.

 

[Jack_Hill]

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.,

 

[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.

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.

 

[Aozora]

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.

In horsepower, of course, it would have been nice to have more power in the P-40 air frame. But the genuinely noticeable deficiency of thrust-to-weight ratio became palpable only toward the end of 1943....

A. S. Nikolay Gerasimovich, how would you evaluate the speed, rate of climb, acceleration, and maneuverability of the P-40? Did it suit you?

N. G. I say again, the P-40 significantly outclassed the Hurricane, and it was far and away above the I-16.

Personally speaking, the P-40 could contend on an equal footing with all the types of Messerschmitts, almost to the end of 1943. If you take into consideration all the tactical and technical characteristics of the P-40, then the Tomahawk was equal to the Bf-109F and the Kittyhawk was slightly better.

Its speed and vertical and horizontal maneuver were good. It was fully competitive with enemy aircraft.

As for acceleration, the P-40 was a bit heavy, but when one had adjusted to the engine, it was normal.

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.

A. S. Nikilay Gerasimovich, could the Cobra really contend with the Bf-109G and FW-190 in aerial combat?

N. G. Yes. The Cobra, especially the Q-5, took second place to no one, and even surpassed all the German fighters.

I flew more than 100 combat sorties in the Cobra, of these 30 in reconnaissance, and fought 17 air combats. The Cobra was not inferior in speed, in acceleration, nor in vertical or horizontal maneuverability. It was a very balanced fighter.

Part 3

Guess the Russians had to learn some engine maintenance.

 

[davparlr]

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.

 

[bobbysocks]

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

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?