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6 hours ago, 71st_AH_Barnacles said:

G10 and Spit XIV a good idea for collector planes?

we enough 109, give me a Me 410 instead and the Allies a C-47

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Switch the C-47 for an A-20 G and I'm OK with the 410.

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On 5/27/2018 at 4:47 PM, II/JG17_HerrMurf said:

Western pilots did NOT have individual control over convergence. That's not how militaries operate. You can't take two anomalies and turn them into blanket statements. That's not how logic works either. Even your quote about Malan's, "own volition," essentially shows it wasn't normal. Convergence was set by the manufacturer and some units changed convergence based upon their primary mission; such as some American P-47 units focusing on ground attack. Individual lieutenants and captains had no authority to change convergence on a whim. Aces, maybe. German Experten were given some latitude. Average line guys, not a freakin chance. USN pilots weren't even assigned individual aircraft so you know none of them were mucking about with their convergence either. This argument has been hashed out in these forums before. It's not how it worked then and it d@mn sure isn't how it works now.

 

 

Didn't even read your comment before I posted but clearly we are on the same page................

The first screenshot is from the book "Spitfire the Canadians"  and the text is from Bill Reale, armourer of 441 and 402 squadrons.

The second one is from Commander Monroe, armament branch of US Navy. From the book "Report of Joint Fighter Conference".

There is more than anecdotal evidence out there about some personal preferences on harmonisation. At least at squadron level. It seems logical that a fresh new replacement has no says in these matter but section leaders with vast experience may have had more than a say in the way and distance at which they shot at the enemy.

 

20180528_170123.jpg

20180528_172447.jpg

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Me410 is more of an 1943/44 Italy plane surely? They didn't really do anything in the BoBP timeline.

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They look good, that's good enough for me.

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55 minutes ago, HR_Zunzun said:

The first screenshot is from the book "Spitfire the Canadians"  and the text is from Bill Reale, armourer of 441 and 402 squadrons.

The second one is from Commander Monroe, armament branch of US Navy. From the book "Report of Joint Fighter Conference".

There is more than anecdotal evidence out there about some personal preferences on harmonisation. At least at squadron level. It seems logical that a fresh new replacement has no says in these matter but section leaders with vast experience may have had more than a say in the way and distance at which they shot at the enemy.

 

20180528_170123.jpg

20180528_172447.jpg

 

Harmonization and convergence, while closely interrelated, are not the same thing. Neither of those exerpts contradict what I've said. Both articles are about ground crew setting harmonization through boresighting. The second article is about testing to find the best harmonization for the fleet while accepting that different units will likely interpret the process and results differently. Individual pilots do not set their own convergence. There are outliers and exceptions but militaries function on uniformity for a reason. Again, you can't take those outliers and exceptions as the standard. It is a false equivalency.

 

Slightly OT, as an avid distance shooter I can tell you that boresighting is great for getting in the ballpark but you'd never use it for anything approaching precision. You have to put it on the bench and set your dope. Similarly, no one boresights and AC and then says, "Yup, we got it." You put it on a bench, send rounds down range at a known distance, and make adjustments. Lots of pic to prove that. Although, at the moment, I am forgetting the name of that process and what the "bench" is called for aircraft.

p-38-lightning-5.jpg

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On 5/27/2018 at 4:47 PM, II/JG17_HerrMurf said:

Western pilots did NOT have individual control over convergence. That's not how militaries operate. You can't take two anomalies and turn them into blanket statements. That's not how logic works either. Even your quote about Malan's, "own volition," essentially shows it wasn't normal. Convergence was set by the manufacturer and some units changed convergence based upon their primary mission; such as some American P-47 units focusing on ground attack. Individual lieutenants and captains had no authority to change convergence on a whim. Aces, maybe. German Experten were given some latitude. Average line guys, not a freakin chance. USN pilots weren't even assigned individual aircraft so you know none of them were mucking about with their convergence either. This argument has been hashed out in these forums before. It's not how it worked then and it d@mn sure isn't how it works now.

 

 

Didn't even read your comment before I posted but clearly we are on the same page................

But at the same time, those excerpts do not contradict the idea that harmonisation was not set in stone (quite the contrary). And that at the squadron level they often chose their own harmonisation.

That was possible and probably the main limitation was the rank and experience of the pilot (it is clear that at least squadron leaders did it). So don´t see any problem in the player choosing it the same way you can choose your fuel amount, external ordinance or when and how you take off.

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14 minutes ago, HR_Zunzun said:

But at the same time, those excerpts do not contradict the idea that harmonisation was not set in stone (quite the contrary). And that at the squadron level they often chose their own harmonisation.

That was possible and probably the main limitation was the rank and experience of the pilot (it is clear that at least squadron leaders did it). So don´t see any problem in the player choosing it the same way you can choose your fuel amount, external ordinance or when and how you take off.

 

Trying to understand the differences between harmonization and convergence (from what I've read they seem like the same thing) or is harmonization the pattern and convergence the distance? We can already set our convergence in game so I don't see much reason to have much more than that unless there is a big difference that I'm missing.

Edited by Legioneod

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1 hour ago, Legioneod said:

 

Trying to understand the differences between harmonization and convergence (from what I've read they seem like the same thing) or is harmonization the pattern and convergence the distance? We can already set our convergence in game so I don't see much reason to have much more than that unless there is a big difference that I'm missing.

 

Convergence is distance, harmonization is the process of setting the individual guns to the desired distance.

 

Result and method, so to speak.

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6 minutes ago, PainGod85 said:

 

Convergence is distance, harmonization is the process of setting the individual guns to the desired distance.

 

Result and method, so to speak.

 

So basically harmonization is just setting the guns to converge at a specific distance? We can already do this in game so why are people arguing about it above?

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2 hours ago, HR_Zunzun said:

But at the same time, those excerpts do not contradict the idea that harmonisation was not set in stone (quite the contrary). And that at the squadron level they often chose their own harmonisation.

That was possible and probably the main limitation was the rank and experience of the pilot (it is clear that at least squadron leaders did it). So don´t see any problem in the player choosing it the same way you can choose your fuel amount, external ordinance or when and how you take off.

 

That is not individual pilots changing convergence on a whim. Several people are taking a narrow focus on an exception and trying to apply it as a rule. A squadron , wing, or AF would do testing and complete a $#!7ton of paperwork to make those changes - and run it up the chain of command and consult with the manufacturer to get it done. A unit trying to tweak their harmonization at a given convergence is a far cry from 'pilots often changed their convergence on their own.'

 

Which is the thing being argued.........................

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On 5/27/2018 at 8:28 AM, PainGod85 said:

 

Nope, horsepower isn't the same.

 

The DB 605 AM reaches 1800 PS at 1.7 ATA and SL, but around 600 m barometric altitude (just before the hydraulic coupling engages the supercharger), that figure goes up to around 1820 PS as thermodynamics dictate colder air is denser, and thus there's more oxygen to burn for the same manifold pressure.

 

DB605G_MW50_powercurve_viaGGH.jpg

Note how the addition of MW-50 charge cooling contributes 100 PS to the engine's power output.

 

The DB 605 DB, running the same fuel at 1.8 ATA produces 1850 PS at SL, with a corresponding increase in power produced as altitude increases up to the point where its SC gear engages.

 

I couldn't find a power graph for the 605D, but the climb rate indicates the engine behaves the same:

 

Me_109K-4_DB605DB_Climb.jpg

 

This time, the SC gear engages at 700 m, with a concurrent drop in climb rate as engine power is funneled into the supercharger impeller.

Hey PainGod. Nice to see you in the IL-2 forums 😃Could you answer a question of mine? How does the 109 maintain constant M.P. up to 700m if it doesn't engage the supercharger until 700m? 

On 5/27/2018 at 7:57 AM, Makz said:

Wheel covers +10 km/h

Retractable tail wheel +12 km/h

Smooth engine cowling +6 km/h

2000 hp +20 km/h

624 km/h on deck

🤩

IF it gets 1.98ata it'll probably do a little over 600kph at S.L., nowhere near 624. The D-9 should still be slightly faster.

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These are some technical data on 109 K-4, the research source is the great book of airplanes of the second world war page 465. The author of the article is Robert Grinsell

 

" Performance k- at 3100 kg:

 

DB 605 ASCM

 

max speed : 608 km/h sea level ; 727 km/h at 6000 m ; 700km/h at 7500 m

 

initial climb : 24 m/sec

 

time to 5000m : 3 min 0sec

time 10000m : 6 min 42sec

time 12000m: 10min 12 sec

 

service sailing : 12.500m"

 

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Japo publication Bf109K-4

 

DB 605D:

 

515/0

645/8,4

670/9

 

DB 605D with MW50:

 

580/0

710/7,5

 

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8 hours ago, II/JG17_HerrMurf said:

 

That is not individual pilots changing convergence on a whim. Several people are taking a narrow focus on an exception and trying to apply it as a rule. A squadron , wing, or AF would do testing and complete a $#!7ton of paperwork to make those changes - and run it up the chain of command and consult with the manufacturer to get it done. A unit trying to tweak their harmonization at a given convergence is a far cry from 'pilots often changed their convergence on their own.'

 

Which is the thing being argued.........................

What I was arguing is this:

 

On 5/27/2018 at 4:47 PM, II/JG17_HerrMurf said:

Western pilots did NOT have individual control over convergence.

 

As not being accurate.

The anecdotal evidence proved that, at least, some individual had a vote on which harmonisation pattern they want for their planes. At least at squadron level (this being commonplace in the US Navy). How far this reached down the ranks I do not know and probably we´ll never know. But it makes sense that individuals that had the rank, the experience and a few kills under their belts could choose a different pattern that suited better their own style of shooting.

Commonplace (along with the ranks)? I don´t think so. Possible? yes. Same as deciding your external ordinance, your fuel load, your aeroplane painting, your patrol area, being able to take off at leisure......

Convergence is a simplistic representation of patterns. Clod has, in my opinion, a good approximation to this as you can change azimuth and elevation to every single gun in your plane and the result will give you different patterns depending on your values. Some of them really unhelpful.  There is even an excel spreadsheet that shows how complex and how different results you can get by changing the values (still I do not know how close to the real thing but much more complex than the simple convergence model).

 

Captura de pantalla 2018-05-29 07.32.16.png

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5 hours ago, Voidhunger said:

Japo publication Bf109K-4

 

DB 605D:

 

515/0

645/8,4

670/9

 

DB 605D with MW50:

 

580/0

710/7,5

 

 

These look like the specs given in the GLC datasheet for the very early 605DM powered 109K at 1,75ata.

 

Specs and curves for the more commonly used DB 605 DB/DC : http://kurfurst.org/Performance_tests/109K_PBLeistungen/Leist_109K_EN.html

14 hours ago, dogeness said:

Hey PainGod. Nice to see you in the IL-2 forums 😃Could you answer a question of mine? How does the 109 maintain constant M.P. up to 700m if it doesn't engage the supercharger until 700m? 

IF it gets 1.98ata it'll probably do a little over 600kph at S.L., nowhere near 624. The D-9 should still be slightly faster.

 

It does engage the supercharger, only at a lower rev speed - the supercharger on the 601/5 is driven through a hydraulic clutch, which uses oil pressure the to adjust the 'slip' of said clutch and thus the rpm the supercharger is running at.

 

Its made up of two oil pumps, one is constantly providing a base pressure, and provides a fair bit of excess manifold pressure which is then throttled (this is essentially the first speed of the supercharger, indicated by the 'uphill'' curve of the engine charts under 2000 m). It is essentially a fixed speed 1st supercharger gear.

 

The second pump is engaged at a given barometric pressure (~altitude of the plane, more or less), hence why it is stated that the supercharger is engaged, but what it really means is that it is at maximum slip / minimum supercharger pressure, and from that onwards the amount of oil pumped is constantly adjusted (increased) as the barometric pressure drops (i.e. as altitude increases). The second pump is essentially act as a variable speed gear ratio. This second pump/speed is much more precise than the first one and delivers only a tiny bit more pressure than is needed, which is then throttled down for the desired manifold pressure. Hence there is minimal loss of power above supercharger engagement level, and hence why the DB power curves are as smooth instead of the common see-saw shape seen on other two speed superchargers. 

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6 hours ago, HR_Zunzun said:

What I was arguing is this:

 

 

As not being accurate.

The anecdotal evidence proved that, at least, some individual had a vote on which harmonisation pattern they want for their planes. At least at squadron level (this being commonplace in the US Navy). How far this reached down the ranks I do not know and probably we´ll never know. But it makes sense that individuals that had the rank, the experience and a few kills under their belts could choose a different pattern that suited better their own style of shooting.

 

<snip>

 

Most of the time, most pilots were not allocated an individual plane that they and only they would fly. Senior pilots might get this treatment, but even flight commanders would not be guaranteed a dedicated aircraft. Perhaps in the quiet periods when in reserve or working up for operations plane assignments might work this way, but not in sustained operations. Any time you have more ready pilots than serviceable planes what do you do - take certain pilots off the roster because "their" plane is not ready? Or is a certain plane unavailable for operations because the assigned pilot is on a weekend leave?  No. Pilots have to be able to operate any of the aircraft allocated to their unit.

 

For this reason, if I were a Squadron Commander, I would want a uniform convergence/harmonization for all of the aircraft in the unit.  Uniformity between squadrons would be much less of an issue. Having said that, I am sure there were always exceptions.

 

In game I want to be able to use the Dowding Spread - so that I can blame my poor results on him. 

 

 

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20 hours ago, HR_Zunzun said:

The first screenshot is from the book "Spitfire the Canadians"  and the text is from Bill Reale, armourer of 441 and 402 squadrons.

The second one is from Commander Monroe, armament branch of US Navy. From the book "Report of Joint Fighter Conference".

There is more than anecdotal evidence out there about some personal preferences on harmonisation. At least at squadron level. It seems logical that a fresh new replacement has no says in these matter but section leaders with vast experience may have had more than a say in the way and distance at which they shot at the enemy.

 

20180528_170123.jpg

20180528_172447.jpg

This is an interesting extract from the above:

 

"The pilots all wanted a different cone of fire, because they all flew differently. Some of them wanted a smaller cone of fire, some of them wanted wider".

 

I read that as historical testimony that all Spitfire pilots could have gun range adjusted to create a bespoke cone of fire to suit their fighting style, with pairs of guns from the left and right wings harmonised at a given range accordingly.  The armourer was the technician that performed the task on instructions from individual pilots. 

 

This information regarding pilot preference corresponds with pilot accounts in books that I have read too.  For example, Wing Leader by 'Johnnie Johnson', Chapter 10, Canadian Wing.  When he joined the wing he looked at combat gun camera footage from his pilots and noticed that one of his pilots gun camera films were 'some of the best ever taken'.  So Johnnie Johnson copied that pilot so that his guns harmonised the same.  So he harmonised his guns to give a 'spot concentration' of fire, which he says is a far more lethal method of obtaining a kill than what he calls, a fairly large 'shotgun' pattern, used by some.  I am very pleased that we are able to harmonise our guns for 'spot concentration' in this simulation.  Nice one Jason and team :)

 

Happy landings,

 

Talisman

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19 hours ago, Legioneod said:

 

Trying to understand the differences between harmonization and convergence (from what I've read they seem like the same thing) or is harmonization the pattern and convergence the distance? We can already set our convergence in game so I don't see much reason to have much more than that unless there is a big difference that I'm missing.

The guns can be harmonised for example by setting the left and right wing inner guns to converge at the same range (250 yards for example) and the left and right wing outer guns to converge at the same range (275 yards for example).  There are many variations of harmony of convergence range that can be achieved.  The more guns you have the more permutations of convergence harmony will be available to create shot-gun like cones of fire and kill zones of different patterns.  For example, some pilots simply harmonised all guns to converge at the same range, rather than different ranges; this type of harmony gave a 'spot' concentration of fire and was a far more lethal method of obtaining a kill.  I am grateful that this combat simulation allows us to use 'spot' harmonisation :)

 

Happy landings,

 

Talisman

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17 hours ago, dogeness said:

Hey PainGod. Nice to see you in the IL-2 forums 😃Could you answer a question of mine? How does the 109 maintain constant M.P. up to 700m if it doesn't engage the supercharger until 700m? 

 

Simple, up to that point the ambient air pressure is still sufficient for the engine's induction system to maintain peak MAP. Essentially, until the supercharger engages, the DB 605 is an aspirated engine.

 

E: Disregard, Kurfürst is almost certainly correct.

Edited by PainGod85

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3 hours ago, VO101Kurfurst said:

 

It does engage the supercharger, only at a lower rev speed - the supercharger on the 601/5 is driven through a hydraulic clutch, which uses oil pressure the to adjust the 'slip' of said clutch and thus the rpm the supercharger is running at.

 

 

 

The supercharger of the Db60x series is driven basically by a hydraulically-operated clutch.

 

This clutch allows the ultimate supercharger drive speed to be very high at low density altitudes (to provide a reasonable critical altitude), and also to be driven at more appropriately lower speeds when at higher density altitudes. This avoids huge parasitic powertrain losses from needlessly over-driving the supercharger impeller.

 

However, such a setup does not address the fact that there is no second stage, thus no intercooling, and thus more intake air heating and less efficiency than two-stage supercharger designs. Also, the impeller design must compromise some efficiency at both the high speeds and low speeds to deal with the wide range of RPM operation. There is also a maximum impeller speed allowable, given that the efficiency loss is quite dramatic as the blade tips reach supersonic speed - this limits the maximum achievable critical altitude for any single-stage supercharger as compared to a multi-stage setup (in which multiple superchargers can be used, each sequentially compressing the intake charge, each specialized for its role and the higher-speed s/c able to be switched in/out of the circuit as altitude changes).

 

It is a clever design which optimizes a single-stage, single-gear supercharger. It does not approach the ultimate efficiency of a multi-stage, multi-gear supercharger. It is much cheaper and lighter than a multi-stage design. Ultimately, the Db605 series engines and its supercharger were designed around the compression limitations of the 87-oct B4 fuel. Even at 1.9ata (which required MW50 to avoid detonation), this is equivalent to 57" Hg or so and the allied superchargers went much higher on the pressures and at much higher altitudes too - because the fuel available could support such design.

 

Obviously the Germans could have used higher octane fuels, but it is debatable whether it would have had any impact on their engine performance - as most of their aircraft and engines were simply not designed for higher boost levels.

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3 hours ago, Venturi said:

 

The supercharger of the Db60x series is driven basically by a hydraulically-operated clutch.

 

This clutch allows the ultimate supercharger drive speed to be very high at low density altitudes (to provide a reasonable critical altitude), and also to be driven at more appropriately lower speeds when at higher density altitudes. This avoids huge parasitic powertrain losses from needlessly over-driving the supercharger impeller.

 

However, such a setup does not address the fact that there is no second stage, thus no intercooling, and thus more intake air heating and less efficiency than two-stage supercharger designs. Also, the impeller design must compromise some efficiency at both the high speeds and low speeds to deal with the wide range of RPM operation. There is also a maximum impeller speed allowable, given that the efficiency loss is quite dramatic as the blade tips reach supersonic speed - this limits the maximum achievable critical altitude for any single-stage supercharger as compared to a multi-stage setup (in which multiple superchargers can be used, each sequentially compressing the intake charge, each specialized for its role and the higher-speed s/c able to be switched in/out of the circuit as altitude changes).

 

It is a clever design which optimizes a single-stage, single-gear supercharger. It does not approach the ultimate efficiency of a multi-stage, multi-gear supercharger. It is much cheaper and lighter than a multi-stage design. Ultimately, the Db605 series engines and its supercharger were designed around the compression limitations of the 87-oct B4 fuel. Even at 1.9ata (which required MW50 to avoid detonation), this is equivalent to 57" Hg or so and the allied superchargers went much higher on the pressures and at much higher altitudes too - because the fuel available could support such design.

 

Obviously the Germans could have used higher octane fuels, but it is debatable whether it would have had any impact on their engine performance - as most of their aircraft and engines were simply not designed for higher boost levels.

 

Indeed that is the purpose - superchargers consume hundreds of horsepower, so improving their efficiency (cutting back on losses) is large potential gain in what you get at the propeller. 

 

Its worth pointing out though two things - firstly that the German, French and Russian engines (the latter often being deriviatives of the former) had ample of swept volume and thus higher boost pressures - all that comes with it, extreme supercharging, intercoolers, two stage superchargers, high octane fuel - were not really necessary. Western Allied inline designs like the Allison or the Merlin had less swept volume, and compensated for it by higher RPMs and higher boosts, making their designers far more supercharging conscious. 

 

The G-14 for example runs at 1,7ata - this is barely +7 lbs/sq. inch in British units, roughly the equivalent of the boost pressure of the first Spitfires when running on 87 octane. On the other hand, its higher compression ratio engine with far higher swept volume. Bothering with heavier and bulkier two stage systems was probably never judged to worth it, simply because the loss of efficiency from these factors (added weight and drag) would likely outweight any efficiency gains in the supercharging. When higher rated altitude was wished for, simply fitting a larger supercharger solved the issue. Hence the fitting of the beefier DB 603 supercharger on the DB 605, creating the 605AS and D engines.

 

All in all, its different engineering approaches to the same goal: higher power. However, it was a given. Countries finished the war with the same basic design that they started the war with, there simply not enough time to develop new engines. So existing designs were improved upon. 

 

As for the German fuels, they did have high octane from the start of the war, in fact the knocking ability of their fuel (cc. 145-150 grade, from 1943) far exceeded the actual needs of their engines and superchargers.

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13 hours ago, VO101Kurfurst said:

 

It does engage the supercharger, only at a lower rev speed - the supercharger on the 601/5 is driven through a hydraulic clutch, which uses oil pressure the to adjust the 'slip' of said clutch and thus the rpm the supercharger is running at.

 

Its made up of two oil pumps, one is constantly providing a base pressure, and provides a fair bit of excess manifold pressure which is then throttled (this is essentially the first speed of the supercharger, indicated by the 'uphill'' curve of the engine charts under 2000 m). It is essentially a fixed speed 1st supercharger gear.

 

The second pump is engaged at a given barometric pressure (~altitude of the plane, more or less), hence why it is stated that the supercharger is engaged, but what it really means is that it is at maximum slip / minimum supercharger pressure, and from that onwards the amount of oil pumped is constantly adjusted (increased) as the barometric pressure drops (i.e. as altitude increases). The second pump is essentially act as a variable speed gear ratio. This second pump/speed is much more precise than the first one and delivers only a tiny bit more pressure than is needed, which is then throttled down for the desired manifold pressure. Hence there is minimal loss of power above supercharger engagement level, and hence why the DB power curves are as smooth instead of the common see-saw shape seen on other two speed superchargers. 

Oh, ok. So before 700m it runs on a single-speed supercharger that has to be throttled, which is why power gradually increases in this range. Then at 700m it engages the variable-speed supercharger. That makes sense. Thanks!

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Quote

Bothering with heavier and bulkier two stage systems was probably never judged to worth it, simply because the loss of efficiency from these factors (added weight and drag)

 

Except that the supercharger system is neither terribly heavy or draggy - especially compare to a larger engine or the complexities of fitting an additional chemical injection systems (which is also another element to fail). Anyway, did not the 605, 603 have 2-stage supercharger variants under development? So clearly it was worth considering as a way to increase power at altitude. Arguably, superchargers are relatively low-risk way of improving power for an existing engine, though you are quite correct in their robbing hp. Turbos are more efficient but a little more complex.

 

The Merlin 100 series for the Hornet (for example) was 2,000 hp at t/o without significant increase in weight or mass. The Griffon with 37l and 1,900 lbs  - similar to a late 605 (36l and c. 1,700lb) - managed over 2,000hp without chemical additives (and the weight that such a system imposes), with the Spit XIV and K-4 being highly comparable.

 

BTW, as the devs are looking to extend BoBp to March '45 then there is a good case for the 1,98 ata on the K-4 as an option, alongside a 25lb Spit IX (and possibly a Sabre IIB Tempest V)

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15 hours ago, VO101Kurfurst said:

As for the German fuels, they did have high octane from the start of the war, in fact the knocking ability of their fuel (cc. 145-150 grade, from 1943) far exceeded the actual needs of their engines and superchargers.

 

Again with no documentation to back up a statement. Some Me110s and few Me109s used C3 fuel late in the BoB. C3 fuel wasn't available in any real quantity til It was required for the BMW801 powered Fw190A.

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13 hours ago, MiloMorai said:

C3 fuel wasn't available in any real quantity til It was required for the BMW801 powered Fw190A.

 

Yup. The bottom line is that it is very resource-intensive to raise octane above a certain point with synthetic fuels (which, all car-oil branding aside, are not inherently superior to natural oils). I've posted on this before here, but basically the Germans had to produce synthetic oils and fuels from coal as they for the most part, did not have natural sources (excepting the Romanian oil fields). This is "synthetic", and highly energy-intensive: https://en.wikipedia.org/wiki/Coal_liquefaction

 

You can add tetraethyl-lead or other knock suppressants, but only up to a point. You need a "base" octane rating as high as it's possible to go, first - to end up with a high total "performance number" or... octane rating equivalent... like 130 etc. Germany could do it, but it cost - and with oil and fuel output already pressured by war demands, it didn't make a whole lot of sense to go crazy on the high-octane fuel, when really the only aero engine they used which was designed for it anyways, was the BMW 801D...

 

So like everything else about the 109, including the clever but by mid-late war, rather straightforward supercharger design and the easily-constructed and simple airframe, the fuel requirements were such that many fighters could be made without overt drain on national resources. There's a reason over 30,000 were able to be made.

 

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5 minutes ago, EAF19_Marsh said:

 

And they never managed to produce in useful quantities, if I recall my Tooze.

 

Several million tons of avgas does strike me as 'useful quantity'. Essentially the whole Luftwaffe run almost entirely on synthethically produced avgas.

 

Coal liquefaction is an old technique that originally was developed at the beginning of the 20th century.[1] The best known CTL process is Fischer-Tropsch(FT) synthesis, named after the inventors Franz Fischer and Hans Tropsch from the Kaiser Wilhelm Institute in the 1920s.[2] The FT synthesis is the basis for indirect coal liquefaction (ICL) technology. Friedrich Bergius, also a German chemist, invented direct coal liquefaction (DCL) as a way to convert lignite into synthetic oil in 1913.

Coal liquefaction became an integral part of the German industry and helped to fuel its military during World War II. Coal liquefaction was an important part of Adolf Hitler's four-year plan of 1936.[3] In the mid 1930s, companies like IG Farben and Ruhrchemie initiated industrial production of synthetic fuels derived from coal. This led to the construction of twelve DCL plants using hydrogenation and nine ICL plants using Fischer-Tropsch synthesis by the end of World War II. In total, CTL provided 92% of Germany’s air fuel and over 50% of its petroleum supply in the 1940s.[1] The DCL and ICL plants effectively complemented each other rather than competed. The reason for this is that coal hydrogenation yields high quality gasoline for aviation and motors, while FT synthesis chiefly produced high quality diesel, lubrication oil, and waxes together with some smaller amounts of lower quality motor gasoline. The DCL plants were also more developed as lignite - the only coal available in many parts of Germany - worked better with hydrogenation than with FT synthesis. After the war, Germany had to abandon its synthetic fuel production as it was prohibited by the Potsdam conference in 1945.[3]

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Several million tons of avgas does strike me as 'useful quantity'. Essentially the whole Luftwaffe run almost entirely on synthethically produced avgas.

 

Given they needed getting on for 10 million barrels per month for the Wehrmacht and IIRC from 1942 Speer started to review the programme as too costly (both nput and opportunity terms) I would say that no, they never managed to make it work in useful quantities. PnL, old son; you need to consider this in your historical analysis.

 

But - I know - the Germans never made a poor decision or failed in any way 😉

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The alternative for synthetic fuel was no fuel at all.

 

Germany simply did not control any significant portion of the oil wells available to the World at the time - there was some old WW2 article I have seen and something like 95% of the then accessible oil output of the World was in the hands of Allied countries - but they had, on the other hand, an abundance of coal and lignite, and the technology to convert it into avgas, even if it was more costly than refining natural crude oil. You can't refine natural crude oil that you do not have access to. 

 

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Sure they have made poor decisions, but investing heavily into synthetic fuel plants before the war and thus largely overcoming a very serious strategic weakness was certainly not one of them.

 

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Sure they have made poor decisions, but investing heavily into synthetic fuel plants before the war and thus largely overcoming a very serious strategic weakness was certainly not one of them.

 

Starting a war with the major economies of Europe while being in said limited fuel situation, then enlarging it to the other great powers when you still have not solved this problem (attacking your major provider) and remain limited by poor access to fuel and other key resources (and no feasible plan to win said war) was a very poor decision. Given the known / predicted fuel requirement of the Wehrmacht, the weakness of synthetic fuel production (high opportunity cost, technical complexity) then suggesting that getting into that very situation while lacking a decent supply of POL was somehow not a poor decision is a strange way of looking at things (brings to mind P. Carrell analysis). At the risk of taking Jeschonik out of context, the 'we don't need any more' mentality is part of a wider symptom that lead to dependence upon this sort of process because adequate strategic thinking was largely absent (Barbarossa being perhaps the most glaring example).

 

They did the best with what they had. It was not enough. The conflicting demand on what they lacked to sustain the war they started have (food, nitrogen, coal, power, fuel) was indicate of the hopeless muddle that characterized their entire planning strategy. The synthetic plants may have provided several million tonnes, but that was nowhere near enough - hence my response about not managing output in meaningful quantited and thus they remained starved of fuel to the war's end.

 

By the time they were dependent on these plants the situation was hopeless and they were  a response akin to a man on his way to the gallows planning to spread his feet wide when the trap-door drops.

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59 minutes ago, EAF19_Marsh said:

 

Starting a war with the major economies of Europe while being in said limited fuel situation, then enlarging it to the other great powers when you still have not solved this problem (attacking your major provider) and remain limited by poor access to fuel and other key resources (and no feasible plan to win said war) was a very poor decision.

 

This goes deeper than just having no feasible plan... The goals were... um... non-existing or unpractical if not outrageous, at best.

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13 minutes ago, Ehret said:

 

This goes deeper than just having no feasible plan... The goals were... um... non-existing or unpractical if not outrageous, at best.

 

Quite. Investing in autarkic fuel production is certainly not without merit, but the investment vs return given the outlay required - and continuing with a strategy that depended at base on significantly more fuel than these plants could possibly produce - is not a good idea. Did they produce fuel? Yes. Did they add to German stocks? Of course. Did they produce a sizeable stock given the requirements of the Wehrmacht? Nope. Not given requirements in 1941 and certainly not when they were supposed to reach peak production 1943-44.

 

I might take on a second job to increase my income, but it would likely not be a sizeable increase to support my fleet of vintage Ferraris, which leads any analysis to question the wisdom of my Ferrari vs. income strategy.

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Well the plan was to get to Azerbaijan's oil but a silly man got distracted by a city that had no tactical importance just because it was named after some other silly man that the first silly man didn't like. Kinda lost an army and never took a step forward after that.

 

Darn I forget the name of that city though????

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