LA-9 vs FW-190A8/9

[Bug_racer]

engineering realities. For me personally, experience setting up and running race engines through various stages of modification (ie. various classes of racing). I stuck with the same engine type through all these so it was instructive particularly about running temperatures vs modification and the role of octane.

I could speak either anecdotally or simply reiterate the engineering guidelines. Increasing octane does absolutely nothing to solve a high running temperature, but it can help with pinging except for one major problem you introduced. You want to raise the octane used by the 601A to C3 fuel and raise the boost for higher climb rating output, to 1475PS at the climb setting no less. Aside from the fact that 605D running C3 can only manage 1300PS at steigleistung, your engine idea still runs just as hot as before, and any benefit regarding predetonation of simply raising fuel octane gets blown out of the water by use of a higher boost.
So you've got an engine which burns pistons under loading, and if it runs at high power settings for any length of time it opens up the seals and bursts into flames, which is just what the 605A used to do on B4.
So let's say you used C3 and didn't raise the boost, it has the same output as before so that's no improvement (raising octane does not improve output by itself) but it won't burn pistons as easy, then again it will be higher maintenance due to the additives being more corrosive in C3 than B4 (stipulated by German wartime fuel production/research documents available on the web). And you've still got the problem about overheat/flaming inherent to the A block. The problem was inadequate oiling for what is basically a 601E with a greater internal capacity. More cubic inches means more cfm means higher operating temperatures.



The overheat problems were never solved for the A block ostensibly until 1945 in the ASB/ASC, which probably uses the bottom end of the D block. The reason for the 605D development was to allow higher boost ratings to be used with the 605 engine, this is not about tensile strength but about operating temperatures. Piston burn was largely solved, but only for the throttle settings used on the 601E which were carried over to the 605A. For a little while it had to be detuned. The way they solved it was reshaping the piston crowns for better excavation of the cylinder, which helps with cylinder temperatures. It still couldn't exceed 1.42ata though, this measure just brought the 605A back to 601E tuning.



It overheated and then started pinging. If it didn't overheat it would run just fine at 1.42ata just like the 601E did. Secondly, even if the pilot carefully controlled the pinging (overheating engines ping worse under loading), like Marsielle did the overheating still caused the seals to open up and the engine flamed. The pilot could die this way, like Marsielle did.
So the motor was derated, I'd say Marsielle's death was the catalyst for this.
Even when piston crowns were improved in various batch redesigns, the engine remained derated for quite some time (it was an on again, off again situation as Kurfürst outlines citing documentation). Even when it was finally cleared for 1.42ata it was still a hot running engine compared to the 605D which has no recorded inherent reliability issues I've seen, and there are plenty of sources which state 1944 605A running with MW50/C3 had a dicey sondernot which could easily damage the engine within a few minutes. I've read nothing other than a reliable 10min sondernot for a 605D on MW50/B4 and a higher boost.
That alone should say something, and it directly infers precisely what I've been saying in mechanical terms.


Hey don't get me wrong, I'll stand corrected as readily as the next bloke, but I'm using clear logic here, with at least some historical reference and see no mechanically sound counter argument.

This has become an interesting engine thread

Increasing octane does absolutely nothing to solve a high running temperature

Wrong : Increasing the octane will allow a slower burning flame front that will produce lower Exhaust Gas Temperatures which in turn will radiate less heat . The combustion temperature will also be reduced . Especially if the engine is close to pre-detonating .



So you've got an engine which burns pistons under loading, and if it runs at high power settings for any length of time it opens up the seals and bursts into flames, which is just what the 605A used to do on B4 :

I dont understand the opens up the seals and bursts into flames bit ?
My assumption : Running higher boost pressures causes the piston rings to warp allowing more combustion pressures to leak past the rings into the oil sump pushing oil out of the breather and probably over the exhaust manifold causing fires ? I doubt the piston would burn a hole before the rings fried first .


raising octane does not improve output by itself : It actually does albeit a small amount . You can lean it out and change the timing on the engine to get the most out of it .

More cubic inches means more cfm means higher operating temperatures :
Raising capacity doesnt mean you have more to cool . A 24l engine running 5:1 compression ratio at 2000rpm will make far less heat than say a 5l engine running 15:1 compression at 10000 rpm . Heat is a factor of 3 main things : Engine size , combustion temperatures (fuel used and compression ratio) and RPM , there are other smaller factors of air flow over engine , radiator size etc


Does anyone know if the Pistons were forged or cast ?

 

[Shortround6]

raising octane does not improve output by itself : It actually does albeit a small amount . You can lean it out and change the timing on the engine to get the most out of it .

Airplane engines are not car engines. While the basic principles are the same some of the details are not.

For instance on many aircraft engines of the time the timing was fixed. If the specs called for 20 degrees before top dead center that is what it was set to and that is what the engine ran at. 600rpm idle or 3000rpm. 1500rpm cruise at 5,000ft or 3000rpm at 30,000ft.
Supercharged aircraft engines are not leaned out for power. At full throttle in many cases they are being fed 30-50% more fuel than they can actually burn in the air available. The extra fuel acts as an anti-detonat in the intake tract (not available to most German engines) by cooling the intake charge due to evaporation. it also acts like an internal coolant in the cylinder, again by absorbing heat but now it is carrying it out the exhaust system. A reason that many aircraft engines trail black smoke from the exhausts at or near full throttle.

Then there is the whole dual number rating thing. Some allied fuels acted like 100 octane (or performance number)when lean and acted like 130 when running in a rich condition. This is not automatic, it depends on the composition of the fuel. before this was fully understood there were actually a few batches of fuel delivered to the US (who had a different fuel spec on the amount of allowable aromatics than the British) That actually would up performing at a lower octane rating when running rich than running lean.

 

[vanir]

Wrong : Increasing the octane will allow a slower burning flame front that will produce lower Exhaust Gas Temperatures which in turn will radiate less heat . The combustion temperature will also be reduced . Especially if the engine is close to pre-detonating .

Not on an open exhaust with good cylinder excavation, and altering boost will get a much greater impact on EGT anyway. (edit) and actually now I'm thinking about it, a higher EGT is actually desireable for lowering combustion chamber temperatures, it helps excavation quite a bit.
In my race engines raising octane didn't solve high running temperatures, I had to get the head reflowed (ports were slowing excavation at the greater cfm). Also I had to increase the radiator volume and was told my setup was oversize for the oil journal drilling of the basic block (I tried bigger sump and playing with the oiling as best I could). This was for the same engine bored/stroked but tuned to the same spec, a good parable for the DB-601E to the 605A trying to run the same tuning. Raising octane didn't help running temperatures one bit, I tried it.

Raising octane did help with the pinging I got with the bigger capacity on 105 grade (I took it up to ~120 grade for track work), but it still ran just as hot and that was killing off a ton of horsepower (~15%). In fact, and this is an entirely anecdotal statement, I swear black and blue it ran even hotter on the higher octane but did ping less (I could control this on the throttle, since I used vacuum slide valve carbs, and also by reducting intake). Proof of this was the fact I had to run cooler plugs on high octane in track tuning than I did for street cruise and pump grade (much more retard though, you're right for that). Also if it helps I used a mechanical ignition system pretty much identical to a aero magneto setup.
So as it turned out I was actually less competitive with a bigger capacity than I was at the smaller one (which had nicer harmonics at high rpm), until I solved the high running temp. Fixing that was what made all the difference, hence my view is the 605D was the proper development of the larger capacity version of the 601 and the 605A was only halfway there.

I dont understand the opens up the seals and bursts into flames bit ?

It opened all the block seals (eg. mainseal) with overheating if run at high boost settings for an extended period, spraying oil backwards over the exhaust and flaming. This is documented.
If you took comprehensive guaging of the temperatures, the oil would run high from the word go, the water would run high at normal power settings and the cylinder head/block temperature would go through the roof at high power settings. A lot of the heat problem in the cylinder is coming from the crank and pistons (not from the combustion chamber), due to inadequate oiling as a cooling effect. The journals were drilled for the 601 cfm flowing 1200-1300PS and not the 605 cfm flowing 1350-1475PS (not to mention it was always intended that it would be taken out to at least 1550PS).

I am saying categorically, a point of which to my mind there is absolutely no question. High combustion chamber temperatures in the 605A are caused by high block/piston temperatures and not high intake temperatures, poor excavation or high EGT. The fact it even flows 1475PS suggests an excellent excavation.
Hence I am equally adamant the primary difference between the 605A and 605D blocks are the oil journal drilling (water jackets are only going to help cylinder head temp, which doesn't solve our oil seals issue).

raising octane does not improve output by itself : It actually does albeit a small amount . You can lean it out and change the timing on the engine to get the most out of it .

Incorrect. Raising octane reduces output by a slight amount in point of fact. I can model this for you if you like and show you the difference in graph. All high output engines run at the lowest possible octane to get the most horsepower (race engine building 1:01 dude), but predetonation and usable/ideal ignition timing dictates the minimum octane. What raising octane allows you to do is advance the ignition more for a lower rpm torque band, but if you're already running an ideal torque band/rpm range then this is no good. It also lets you raise boost or dynamic compression for a total net gain even though the initial raising of octane actually lowers your base output.

It's like this, on a say 300hp engine you drop to 293hp raising octane but what you do is raise boost from 1 bar to 1.2 bar for a net return of 330hp.
Alternatively on an engine producing 400ft/lbs at 3000rpm but 250ft/lbs at 2500rpm you raise octane and advance timing for 385ft/lbs at 3000rpm and 300ft/lbs at 2500rpm. Much quicker in acceleration off the mark but you might lose a touch coming out of fast turns (picking it up coming out of slow turns, you get the idea).

Also you don't lean out when raising octane if you're in it for the output (you could do that for cruise efficiency, you'll get more out of a tank), what you do is advance the timing (or raise your dynamic compression).

Raising capacity doesnt mean you have more to cool .

More cfm means more heat. The easiest way to get more cfm is more cubic inches. This is a rule of thumb. Generally speaking larger capacity engines are a larger external block, so that solves the higher running temperatures with having more meat.
It becomes a problem with stroker engines, or raising swept capacity on a common block. It's elementary.

 

[Bug_racer]

Not on an open exhaust with good cylinder excavation, and altering boost will get a much greater impact on EGT anyway. (edit) and actually now I'm thinking about it, a higher EGT is actually desireable for lowering combustion chamber temperatures, it helps excavation quite a bit.
In my race engines raising octane didn't solve high running temperatures, I had to get the head reflowed (ports were slowing excavation at the greater cfm). Also I had to increase the radiator volume and was told my setup was oversize for the oil journal drilling of the basic block (I tried bigger sump and playing with the oiling as best I could). This was for the same engine bored/stroked but tuned to the same spec, a good parable for the DB-601E to the 605A trying to run the same tuning. Raising octane didn't help running temperatures one bit, I tried it.

Raising octane did help with the pinging I got with the bigger capacity on 105 grade (I took it up to ~120 grade for track work), but it still ran just as hot and that was killing off a ton of horsepower (~15%). In fact, and this is an entirely anecdotal statement, I swear black and blue it ran even hotter on the higher octane but did ping less (I could control this on the throttle, since I used vacuum slide valve carbs, and also by reducting intake). Proof of this was the fact I had to run cooler plugs on high octane in track tuning than I did for street cruise and pump grade (much more retard though, you're right for that). Also if it helps I used a mechanical ignition system pretty much identical to a aero magneto setup.
So as it turned out I was actually less competitive with a bigger capacity than I was at the smaller one (which had nicer harmonics at high rpm), until I solved the high running temp. Fixing that was what made all the difference, hence my view is the 605D was the proper development of the larger capacity version of the 601 and the 605A was only halfway there.



It opened all the block seals (eg. mainseal) with overheating if run at high boost settings for an extended period, spraying oil backwards over the exhaust and flaming. This is documented.
If you took comprehensive guaging of the temperatures, the oil would run high from the word go, the water would run high at normal power settings and the cylinder head/block temperature would go through the roof at high power settings. A lot of the heat problem in the cylinder is coming from the crank and pistons (not from the combustion chamber), due to inadequate oiling as a cooling effect. The journals were drilled for the 601 cfm flowing 1200-1300PS and not the 605 cfm flowing 1350-1475PS (not to mention it was always intended that it would be taken out to at least 1550PS).

I am saying categorically, a point of which to my mind there is absolutely no question. High combustion chamber temperatures in the 605A are caused by high block/piston temperatures and not high intake temperatures, poor excavation or high EGT. The fact it even flows 1475PS suggests an excellent excavation.
Hence I am equally adamant the primary difference between the 605A and 605D blocks are the oil journal drilling (water jackets are only going to help cylinder head temp, which doesn't solve our oil seals issue).



Incorrect. Raising octane reduces output by a slight amount in point of fact. I can model this for you if you like and show you the difference in graph. All high output engines run at the lowest possible octane to get the most horsepower (race engine building 1:01 dude), but predetonation and usable/ideal ignition timing dictates the minimum octane. What raising octane allows you to do is advance the ignition more for a lower rpm torque band, but if you're already running an ideal torque band/rpm range then this is no good. It also lets you raise boost or dynamic compression for a total net gain even though the initial raising of octane actually lowers your base output.

It's like this, on a say 300hp engine you drop to 293hp raising octane but what you do is raise boost from 1 bar to 1.2 bar for a net return of 330hp.
Alternatively on an engine producing 400ft/lbs at 3000rpm but 250ft/lbs at 2500rpm you raise octane and advance timing for 385ft/lbs at 3000rpm and 300ft/lbs at 2500rpm. Much quicker in acceleration off the mark but you might lose a touch coming out of fast turns (picking it up coming out of slow turns, you get the idea).

Also you don't lean out when raising octane if you're in it for the output (you could do that for cruise efficiency, you'll get more out of a tank), what you do is advance the timing (or raise your dynamic compression).



More cfm means more heat. The easiest way to get more cfm is more cubic inches. This is a rule of thumb. Generally speaking larger capacity engines are a larger external block, so that solves the higher running temperatures with having more meat.
It becomes a problem with stroker engines, or raising swept capacity on a common block. It's elementary.

and actually now I'm thinking about it, a higher EGT is actually desireable for lowering combustion chamber temperatures, it helps excavation quite a bit.

There is a desired egt at which the engine operates at its most efficient . If you run too higher egt your probably pinging/predetonating . Its kind of like the same as engine operating temperature . The desired water/coolant temp is around 90-100 , any more than that becomes damaging to the coolant system .
Raising octane is to help in the combustion temperature , not engine operating temperatures . Combustion temperatures should decrease slightly . The effects are minimal though . Dumping more fuel in to cool the combustion chamber down would be more effective , as would water/meth injection .



Raising octane did help with the pinging I got with the bigger capacity on 105 grade (I took it up to ~120 grade for track work), but it still ran just as hot and that was killing off a ton of horsepower (~15%

This shows you your egt's are too high which affects your hp . When searching for hp there are safe limits , go beyond these limits you just loose power and run too hot . My personal opinion , back the timing off a few degrees and run it a bit richer and you'll probably run cooler and make the same if not more hp . Are you running carbs ? What ignition system ?




It opened all the block seals (eg. mainseal) with overheating if run at high boost settings for an extended period, spraying oil backwards over the exhaust and flaming

This to me says there are more issues with the breather system than anything else . Im not too sure what system they used but some pics of it would be nice .



Incorrect. Raising octane reduces output by a slight amount in point of fact. I can model this for you if you like and show you the difference in graph

I dont understand how this is possible when there is more energy per volume with higher octane fuels ? The effects I admit are minimal anyway so its a waste to just run high octane fuel without making any changes .





All high output engines run at the lowest possible octane to get the most horsepower (race engine building 1:01 dude),

Im sure you mean it the other way round ! Highest possible octane available for the class ! Have you noticed how many racers are converting to ethanol or E85 now that its more widely available ? yes you need bigger injectors and more fuel (almost as much as Methanol!) But its still considered pump gas and has octane of 110 or so .


It's like this, on a say 300hp engine you drop to 293hp raising octane but what you do is raise boost from 1 bar to 1.2 bar for a net return of 330hp.
Alternatively on an engine producing 400ft/lbs at 3000rpm but 250ft/lbs at 2500rpm you raise octane and advance timing for 385ft/lbs at 3000rpm and 300ft/lbs at 2500rpm. Much quicker in acceleration off the mark but you might lose a touch coming out of fast turns (picking it up coming out of slow turns, you get the idea).

I think your getting compression ratio confused with octane here . If you lower the compression ratio of an engine and run the same boost pressure you will loose peak power and torque , say your running a turbo (I dont think it will affect a supercharged engine the same ) , your boost will come on later and you will have less , but you can raise the boost pressure and run the same octane rating of fuel to gain an overall raise in the amount of power . Lowering the compression ratio also adds to the longetivity of an engine . In regards to the timing it really depends upon the cams etc as to what works best . You can though add more advance with higher octane fuels .



More cfm means more heat. The easiest way to get more cfm is more cubic inches. This is a rule of thumb. Generally speaking larger capacity engines are a larger external block, so that solves the higher running temperatures with having more meat.
It becomes a problem with stroker engines, or raising swept capacity on a common block. It's elementary.

If the engines dont have problems with cooling standard then they usually can handle the extra volume from boring / stroking . Its rpm/compression increases that really give issues with heat . The issues your probably seeing with extra heat from boring/stroking are probably engines still injecting the same amount of fuel before the modification and having extra airflow causing them to run too lean

 

[Vincenzo]

Hello Vincenzo
As I wrote, the number of serviceable single engine fighters was 980 according to Price, see Luftwaffe Order Of Battle on 17 May 1943 - The Air Combat Wiki
My memory made a trick on date , the right one is 17 May 43, Price usually gives July figure but not for 43.

But you are right that LW had in its first line units 1849 single-engine fighters on 30 June 43 according to Williamson Murray. If the Price's figure is correct, LW serviceably rate was even worse than I remembered, c. 55% (I used 31.5.43 strength figure as a base) 27 May was a bit bad date for LW, for ex JG 77 was in very bad shape. On 31 Aug 43 serviceable rate was 64,4% (1019 out of 1581 according to Williamson Murray.

Juha

good link, ty, i checked with ww2.dk and there are some minor wrongs (as unit with 109 indicated with 190 but maybe a wrong from web compilator).
i thinked that our difference came from different status, strenght or ready planes and so i've asked you but you don't replyed me.
we have in 17 may around 280 ready fighters (2,26 (but I/26),1 and II/11 and 11/54) with a 370 fighters strenght

for serviceablity i can add that for 17th may we have 1493 strenght fighter and 1032 serviceable so 69%
se serviceable are 980 (this is w/o jabos and fighters in reforming unit) the strenght it's 1355 and serviceability rate go to 72%

 

[Kurfürst]

Nothing to do with the title of this thread but
IMHO British had Fw 190A more or less under control in 43. On 1.1.43 RAF had in first line sqns in UK 162 Spit IXs, c. 200 Typhoons and a bit under 250 Mustang Is/IAs. LW had against them, IIRC, c. 250 109Gs and Fw190As. So especially in low level fighting RAF had a/c to combat LW fighters. During 43 RAF got longer range radars for fighter control over France and improved its tactics, so it's not surprising that with increasingly powerful and effective USAAF in its side RAF began gaining upper hand during the later part of 43. On 30 Jun 43 RAF had c. 170 first class Spits (IXs, XIIs and VIIs), c. 350 Typhoons and c. 250 Mustang Is/IAs in first line sqns in UK, With 8th AF that was clearly enough against LW fighters stationed alongside NW Europe coastal areas.

Juha

Interesting figures Juha, the RAF first line strenght remains somewhat of a mystery, although we can gauge fairly accurately to ratio of moden and semi-obsolate fighters during 1943 from the number of Squadrons operating them.

Do you have perhaps even more detailed figures for all types of fighters and their servicability at that date, ie. the number of Fives and their servicibilty etc? It would be really nice to see actual figures for both sides.

Ie. the 162 Spit IXs in January 1943 agrees well with 10 Spit Mark IX Squadrons listed operating them. Theoretically the 10 Squadron establishment should around 200-220 Spits present, of which there appears that ca 160 could be maintained. British practice was also different from German - Squadrons had an establishment of 20-22 planes per fighter Squadron, but these included the Sqn's immidiate reserve aircraft, and in practice, without exception 12 or sometimes 13 aircraft would fly mission from a Squadron. There's no doubt that the RAF had enough fighters to against the small "guerilla" JGs stationed in France (which had no importance to the Germans), but the mission logs I've seen it appears that Mark Vs continued to fly the majority of the sorties until the end of 1943. Tiffies and Allisonstangs flew as well, but primarly as fighter bombers to my knowledge - save for anti-Jabo Tiffies of course.

 

[claidemore]

Interesting figures Juha, the RAF first line strenght remains somewhat of a mystery, although we can gauge fairly accurately to ratio of moden and semi-obsolate fighters during 1943 from the number of Squadrons operating them.

Do you have perhaps even more detailed figures for all types of fighters and their servicability at that date, ie. the number of Fives and their servicibilty etc? It would be really nice to see actual figures for both sides.

Ie. the 162 Spit IXs in January 1943 agrees well with 10 Spit Mark IX Squadrons listed operating them. Theoretically the 10 Squadron establishment should around 200-220 Spits present, of which there appears that ca 160 could be maintained. British practice was also different from German - Squadrons had an establishment of 20-22 planes per fighter Squadron, but these included the Sqn's immidiate reserve aircraft, and in practice, without exception 12 or sometimes 13 aircraft would fly mission from a Squadron. There's no doubt that the RAF had enough fighters to against the small "guerilla" JGs stationed in France (which had no importance to the Germans), but the mission logs I've seen it appears that Mark Vs continued to fly the majority of the sorties until the end of 1943. Tiffies and Allisonstangs flew as well, but primarly as fighter bombers to my knowledge - save for anti-Jabo Tiffies of course.

Just looking at the sample of combat reports on Mikes site I see 8 squadrons with MkIXs in January 1943. From Mikes sampling of combat reports for the year 1943 I count 22 different squadrons using Mk IXs. This is not a total list, just a sample, and units would have rotated in and out of front line service.
According to the 2TAF order of battle only one 'front line' squadron, Czech 310 was using MkV's during June 1944. They flew some ground attack at Normandy from Tangmere, and never did operate out of a European base. This was basically a reserve squadron.
June 1944 there were 25 Spit IX squadrons on front line service, 5 Spit IX squadrons in reserve, and 7 Spit V squads in reserve. Two Tempest V squadrons, 6 Mustang III squads, 17 Typhoon squads, two Spit XIV squads and a few miscileaneous squads flying Spit IXs, Vs, etc.
One of the 7 Mk V squads was 402, which according to squadron history was flying Mk IXs at that time. Ditto for 501 Sq. All the other Mk V reserve squads had converted to either Mustang II's, Mk IXs , Mk XIVs or Tempest V by August of 44.
Here's a link that shows RAF squadrons and types with dates. RAF Fighter Command Index Shouldn't be too hard to add up the MkIX and MkV squadrons during 1943 using that site.

 

[Vincenzo]

as already writed there were 20 squadrons with Spit IX in 1st jan '44 (was not uncommon that a squadron with IX back to V ) and 9 in january '43 (+2 mixed with V and VI) this only in british islands.

 

[VG-33]

Sorry, I can't see any more similarity beyween these two aircraft, and any other two radial engined, low-winged fighters of the time:

but, from the website of the company that performed the restoration: August 2003



Not sure how htis would compare with the FW-190 though, but it would give some indication of the climb performance from a real-world experience.

As a whole, i agree with you.
I just want to point at a detail:

Unlike the La-7, the La-9 had no combat slats that are represented at your draw. The reason is that he had a laminarised TsAGI wing and fin profiles, that explains also it's Mustang-like square wing tips. It's difficult to keep laminar conditions on rounded shapes. Carrying much more fuel the plane was heavier 3675 kg unstead 3250 but it's range was 1 735 km instead of 635/990. The La-7 in turn was a pure Close-in tight high -G frontal fighter, with no escort mission ability.

This sovietmade kind of "mustang" was intended to use a Shvetsov M-83 engine, reaching 725 km/h with it, since the serial La-7 was able to give only 701-705 km/h using the same one. Even qualified at state trials this engine for some valuable reasons and some not, was never to be mass-produced.

Even without it, using the old M-82T and without combat slats, from Mark Hannah and french collectors opinion like Christophe Jacquard, Jean Salis, Didier Chables and others it's one of the nimbliest warbirds ever flown...At least at Spitfire level, except for roll that's much better of course for the soviet plane.

So it could outurn and outfight the FW-190A-8 with ease when reduced to the La-7 weight, the better manufacturing quality and some improvements in the late M-82 FN engine allowed to consider the "forsage" output as a nominal one : 640 km/h at SL at 1850-1870 hp. 600 km/h at ~ 1615 hp at SL in nominal power "max continuous course" by soviet standards.

Regards

 

[Juha]

Hello Vincenzo
thanks for your effort, I'm now too busy to make my own calculations, so I just took some ready figures from a couple good sources that first came into my mind. I had seen Price's figures in net a rather long time ago and decided to give the link to you and googled LW OoB and found that Wiki page It wasn't the site I was looking for but seemed interesting, I'll look it again later for its late OoBs.

Hello Kurfürst
I calculated those figures from OoBs in Foreman's FC War diaries Jan 42 to June 43 plus made some cross-checking with my decades old notes on info on RAF a/c stocks. It would be easy to add the info on Mk Vs if I had time but that is scare now.

IMHO Mk Vs could well be used in 43 at least as close escorts to British medium bombers. They lacked some acceleration but turned almost as well as Mk IXs and rolled as well and that was IMHO what was needed for the rather passive role of close escort. Their use in a more active role as escort cover was more problematic. IMHO Mk V with +16in boost was OK against 109G at height band 6500-13500ft and against 190A-5 at height band 10000-13500ft. The duty of Mk IX sqns was to protect escorts from attacks above as high escort cover and also try to disrupt LW attack formations and engage them before they could attack other escorts and /or bombers. I also think that in at least early 43 most of the escorts were Mk Vs, say 4 close escort sqns plus 2 escort cover sqns, only 2 high escort cover sqns had Spit IXs, or at least that was fairly typical case IIRC. RAF clearly could have used more Mk IXs if it has had them. Clearly MTO at that time sucked Merlin 60-series Spits away from FC but it also sucked in LW fighters.

Again IIRC 43 was the year when Typhoon's role chanced from fighter to mainly fighter bomber. Mustang Is/IAs made mostly tac recce and long range nuisance raids relying mostly strafing. But its long time ago when I read on RAF's use of Allison Mustangs.

Juha

 

[Milosh]

RAF total strength of Merlin 45 type and 60 type Spitfires as of 3rd September 1943.

3,312 Spit V and VI
1,525 Spit VII, VIII, LF VIII, IX and LF IX

via Niel Stirling

Data for end of November 1943, including Ergänzungsgruppen:
1397 Bf109 (all subtypes)
563 Fw190 (all subtypes)

via yogy

 

[Knegel]

It overheated and then started pinging. If it didn't overheat it would run just fine at 1.42ata just like the 601E did.

The 601E did overheat on 1.42ata, thats why it was limited to a few miniutes on this setting, called WEP.
All engines overheat on WEP to a stage where detonations happen, the normal way to be able to run on the same setting for longer time was to use higher octan fuel.

A side from the fact that 605D running C3 can only manage 1300PS at steigleistung,....

Thats not a fact, thats wrong!! The 605DB with C3 fuel, without MW50, could run on 1.8ata on WEP and it had 1430PS combat/climb.

Secondly, even if the pilot carefully controlled the pinging (overheating engines ping worse under loading), like Marsielle did the overheating still caused the seals to open up and the engine flamed. The pilot could die this way, like Marsielle did.
So the motor was derated, I'd say Marsielle's death was the catalyst for this.

Aha, so you have more information on why Marsailles engine did fail??
Afaik Marsaille dont had enemy contact while his last flight, so i doubt that he did use WEP at all.
I think you have a misunderstanding and mix up the behaviour of a car/bike engine vs a plane engine. A propeller never reach the extreme counter forces like a wheel, as such there is not that much of a high loading difference, and the pilot cant do that much to it with a constand speed propeller, appart from flying faster, what is a must with WEP anayway.

I've read nothing other than a reliable 10min sondernot for a 605D on MW50/B4 and a higher boost.
That alone should say something, and it directly infers precisely what I've been saying in mechanical terms.

Yes, this say something, it say that the MW50 damage the oil film on some parts after a while, so they limit it at once to 10 minutes. Thats why they need to shut it down, not the temperature. They also need to shut MW50 down after 10 minutes, when they use it only as Ladeluft Kühlung(MW50 + 1.42 ata). That why all MW50 boosted engine have this 10 min limit, not just the german engines.

I absolutly dont see any reason why the DB605A in late 1943 shouldnt be able to run longer time than WEP, when using C3 fuel.
The Merlin66 had same trouble like the DB605A when running on low octan fuel, and later they could run on a way higher presure by using 150 octan fuel, still the engine did overheat on the same high presure using 130 octan fuel.

I never did read that the DB605A was a extraordinary hot engine, its initial WEP limitation was related to a bad bearing and some other things that got fixed mid/late 1943. From that point onward, the engine was able to run on WEP, the limitation was the same like the Merlin running on WEP. I have no doubt that the presure could get raised, same like in many other engines, by using higher octan fuel.

Greetings,

Knegel

 

[claidemore]

Totally off the La9 topic, but the thread seems to have sprouted this rabbit trail.

Spent the evening going through the RAF Fighter Command plane types for Europe during 1943.
10 squadrons flew the Spitfire Mk IX exclusively in 1943.
5 squadrons flew the Mk V exclusively during 1943.
28 squadrons flew both the Mk V and the Mk IX,( majority of those flew the V early in the year and switched to the IX during the middle months of 43. There were a few who started 43 with IXs then rotated back to Mk Vs.)
Several other squadrons flew Mk VI, VII or XII Spitfires, combinations of Mk Vs and Mustangs etc.
Total of 51 squadrons flew Spitfires of various marks during 1943 (a few squadrons were renamed so there are some duplicates in that number)
Add to that 20 squadrons flying Typhoons.

Note: these are for Fighter Command, Northern Europe and does not include other theatres unless I missed a squadron that moved out of ETO during 43.

 

[Juha]

Hello Kurfürst
made a quick check on Typhoons and yes it was only in autumn 43 when conversion from fighter to fighter-bomber duties began in earnest, before that their offensive work was mostly fighter sweeps, circuses etc even if the first two Typhoon fighter-bomber sqns were formed tiwards end of 42.

Juha

 

[Vincenzo]

Totally off the La9 topic, but the thread seems to have sprouted this rabbit trail.

Spent the evening going through the RAF Fighter Command plane types for Europe during 1943.
10 squadrons flew the Spitfire Mk IX exclusively in 1943.
5 squadrons flew the Mk V exclusively during 1943.
28 squadrons flew both the Mk V and the Mk IX,( majority of those flew the V early in the year and switched to the IX during the middle months of 43. There were a few who started 43 with IXs then rotated back to Mk Vs.)
Several other squadrons flew Mk VI, VII or XII Spitfires, combinations of Mk Vs and Mustangs etc.
Total of 51 squadrons flew Spitfires of various marks during 1943 (a few squadrons were renamed so there are some duplicates in that number)
Add to that 20 squadrons flying Typhoons.

Note: these are for Fighter Command, Northern Europe and does not include other theatres unless I missed a squadron that moved out of ETO during 43.

this are the squadrons with IX alone in jan '43: 64,122,306,315,331,332,340,402,611, so you conted 10 you can tell me what's the 10th? (i've 403 with both V and IX, and 124 with VI IX)
as that 1st january '44 there are 20 Spit IX squadrons and 10 or 9 has IX in january '43 we have that of the 28 only a part go to V to IX for remain with IX

 

[Kurfürst]

RAF total strength of Merlin 45 type and 60 type Spitfires as of 3rd September 1943.

3,312 Spit V and VI
1,525 Spit VII, VIII, LF VIII, IX and LF IX

via Niel Stirling

Data for end of November 1943, including Ergänzungsgruppen:
1397 Bf109 (all subtypes)
563 Fw190 (all subtypes)

via yogy

I think the RAF strenght is something different, including aircraft in storage (having some of those tables provided by Stirling, there seems to be lot of retired Spit Is etc. appearing in those), whereas the LW strenght is aircraft issued to units (including the OTU Ergänzungseinheiten), but not reserves, storage, retired aiframes etc.

 

[Kurfürst]

apparently not in practise. The document I read specified dramatic reduction in engine life with these setups (dozens of hours), and was quite literate about the ten minute limitation on use being unrealistic, and for extreme emergencies only. The cooldown period was ten minutes.

I am not sure if I have seen those, could you share it?

I'm well aware of this, although the tuning changes are important (higher boost, different magneto setups). For simplicity sake the B4/MW50 or straight C3/1550PS are referred to as the DB motor and the C3/MW50 setup as the DC. This follows general notation.

Do you know perhaps the exact tuning changes required?

What I said is true for the point there is no evidence the 605D ever used C3/MW50 in service, and there is similarly no evidentiary support for the ASC engine ever being fitted (which ostensibly follows the same rules ASB/ASC).

I am not sure about the ASB/ASC, though some sources like Prien claim this, however the 605D/C3/MW50 case is pretty clear, it was used. See:

This wasn't my preferred assumption, I in fact argued that it is likely field use differed from red tape bureacracy particularly during the last months of the war. I cited there was no reason to my mind field mechanics could not get any G-10 or K-4 in the field and tweak it for use of C3 stocks held for 190A's, thus there is no reason there might not have been individual examples of 2000PS Me-109's running around. But the counter argument was this does not appear in any documentation, that the 605D or ASB were never cleared for use of C3/MW50 (ie. 1.98ata) in the field by the administration.

Let me put it another way for simplicity sake, saying exactly the same thing. The highest boost rating cleared for the Me109 was 1.8ata,

Of course it was. The december 1944 DB 605DB/DC manual notes 1.98ata as the maximum for the 605DC configuration

as well as the January 1945 Daimler-Benz records noting it was cleared for service, but it was recalled in January due to some problems, which I believe were spark plug QC related. It was then successfully tested in Rechlin, field tested by II/JG 11, and cleared for service by March 1945 the latest, see: Kurfrst - OKL, GdJ-Grp. Qu-, Br. B. Nr. 1561/45 g.Kdos. von 20. Mrz 1945.

this other business was about reiterating that C3 could not be used with an A block without MW50 because it already ran hot and burned pistons on B4 fuel, and it was a problem unrelated to predetonation (but in fact caused it).

The 605AM manual notes that C-3 can be used without MW-50 in an emergeny at full boost, but you are probably right about higher temperatures; however its not fuel related (the advantage of using C-3 was that it could sustain higher boost without pre-detonation), but the fact that MW-50 injection apart from its charge cooling benefits also gave the engine a tremendeous cooling boost as the water evaporated in the combustion chamber and draw heat away. In fact the DB datasheets show that cooling requirements of the 605A at 1800 PS/1.7ata with MW-50 injection are actually lower than the cooling requirements of the engine at 1310 PS/1.3 without MW-50 injection!

Just curious Kurfürst, what exactly do you think the difference is between the 605A and the 605D specifically, aside from the supercharger and larger oil cooler? Over 30 months of redevelopment, were they smoking joints in the back room?

I don't know all details, but know that the 605D used several other parts from the DB 603, and the compression ratio was also higher, 8.5 vs 7.5. But I don't have a document comparing the A-series and the D-series. Also keep in mind, the D-series was under development parallel to the DB 605A, being initially a variant using C-3 avgas as opposed to B-4. It went through quite a lot of changed between 42 and 44.

 

[claidemore]

this are the squadrons with IX alone in jan '43: 64,122,306,315,331,332,340,402,611, so you conted 10 you can tell me what's the 10th? (i've 403 with both V and IX, and 124 with VI IX)
as that 1st january '44 there are 20 Spit IX squadrons and 10 or 9 has IX in january '43 we have that of the 28 only a part go to V to IX for remain with IX

Hi Vincenzo, I have 403 squadron converting to Mk IXs January 43, and continuing with the IX and XVI till wars end. They might have had a few Mk Vs early in the year.
124 Sq I have with IX and VIIs (not VI's).

 

[Vincenzo]

Hi Vincenzo, I have 403 squadron converting to Mk IXs January 43, and continuing with the IX and XVI till wars end. They might have had a few Mk Vs early in the year.
124 Sq I have with IX and VIIs (not VI's).

i've 403rd flying with V until january '43 included so maybe they has the V early in jan and not in late jan.
for the 124th i've VII only form march '43 and VI until july '43