Post Battle of Britain: Luftwaffe/Axis options

[Hood]

'wing plugs' so the U/C legs can be attached further away one from another, while being closer to vertical when extended; not as big a plug as on the 109H probably, though, to keep drag in check; a MG 151/20 in each plug

Sounds a lot like the Me 209 (II). I wonder if the 209 (II) wing could be fitted to a stock Bf 109?

 

[tomo pauk]

Sounds a lot like the Me 209 (II). I wonder if the 209 (II) wing could be fitted to a stock Bf 109?

They probably could, the 209 (II) fuselage was stock 109 fuselage IIRC.

@HoHun - help

 

[HoHun]

Hi Tomo,

Sounds a lot like the Me 209 (II). I wonder if the 209 (II) wing could be fitted to a stock Bf 109?

They probably could, the 209 (II) fuselage was stock 109 fuselage IIRC.

@HoHun - help

I have no deeper insights regarding that question, but it might be worth it to have a look at Me 109 V31, Werk-Nr. 5642, which was fitted with a wide-track landing gear and a belly radiator for test purposes. (According to test report VB-109-15-L-42, available at wwiiaircraftperformance.com, this radiator was virtually identical in terms of effectiveness and aerodynamic afficiency to the standard Me 109 oil and coolant radiators.)

Regards,

Henning (HoHun)

 

[T. A. Gardner]

Sounds a lot like the Me 209 (II). I wonder if the 209 (II) wing could be fitted to a stock Bf 109?

They probably could, the 209 (II) fuselage was stock 109 fuselage IIRC.

@HoHun - help

The fuselage was about 65% common with the G. There were differences in the tail assembly and of course, a whole new nose housing the Jumo 211 engine. The problem with the 209 ii is that as tested it didn't perform any better than the Me 109 and was markedly slower than the FW 190D so there was little incentive to put it in production.

 

[Hood]

My musing is probably academic. The Me 209 (II) undercarriage is better but it still only has one13-20mm calibre weapon per wing, just moved into the wingroot. I suppose this wouldn't preclude external gun pods like some Me 109 variants had, but it's hardly an improvement.
The Me 309 in contrast bristled with guns, perhaps too many.
I wonder if an Me 309 with, say, an Mk108 through the propeller shaft and four wing guns and no pressurised cockpit would have been more acceptable, I'd even go tailwheel if that would help lighten it.

 

[tomo pauk]

The fuselage was about 65% common with the G. There were differences in the tail assembly and of course, a whole new nose housing the Jumo 211 engine. The problem with the 209 ii is that as tested it didn't perform any better than the Me 109 and was markedly slower than the FW 190D so there was little incentive to put it in production.

Looking a bit at the Wikipedia page, it seems to me that a good history of Me 209 II (1943) is yet to be written. Eg. the statement 'It was 50 km/h (31 mph) slower than the Fw 190D and offered no improvement in handling characteristics.' is as cheesy as it is possible - the 190D was not a thing in late 1943 when the 209 was tested.
Then, there was no Jumo 213E in 1943, there is barely the Jumo 213A to be used for testing (there is a major difference between 213E and 213A altitude capabilities).
The Jumo 211 is, by 1943, obsolescent; still, it went to power Bf 109 off-springs post-war.

Unfortunately, the books by Green (and Swanborough) from 1980s/70s left a huge minefield of misinformation about German aircraft, that a lot of people today repeat in their books.
(I acknowledge the authors that actually do the homework)
German Wikipedia states that prioritization of Me 262 is what doomed the 209.

My musing is probably academic. The Me 209 (II) undercarriage is better but it still only has one13-20mm calibre weapon per wing, just moved into the wingroot. I suppose this wouldn't preclude external gun pods like some Me 109 variants had, but it's hardly an improvement.

Mostly the improvement is the ground handling, since there is no wheel and U/C leg angle to fool the novice pilots?

The Me 309 in contrast bristled with guns, perhaps too many.
I wonder if an Me 309 with, say, an Mk108 through the propeller shaft and four wing guns and no pressurised cockpit would have been more acceptable, I'd even go tailwheel if that would help lighten it.

Too many, indeed, up to 7 guns were envisioned. AIrcraft was too heavy for it's small wing (barely bigger thaan on the 109), with the heavy DB 603 in the nose, such a heavy battery of guns & ammo, fuel tankage need to be big...
I'd probably go with a lighter DB 605 instead the 603, and indeed with a reduced weapon setup.

Or - have MTT do a workable 1-engined jet fighter...

 

[HoHun]

Hi Tomo,

Looking a bit at the Wikipedia page, it seems to me that a good history of Me 209 II (1943) is yet to be written.

You might be right. A friend of mine looked into this a couple of years back, and was surprised that the best overview of Me 209 development he could find was written by no-one less than Martin Caidin!

Mostly the improvement is the ground handling, since there is no wheel and U/C leg angle to fool the novice pilots?

To be honest, I believe the Me 109's bad reputation vis-a-vis its contemporaries in this regard is entirely undeserved. I took a hard look at all available statistics, loss lists etc. I could find, and there is nothing in there that suggests the Me 109 was actually less save than the Fw 190. I can well imagine that the Me 109 behaved in a way that had the pilot's hair standing on end after each landing, but there don't seem to have been any more injured pilots or damaged or written-off aircraft when operating Messerschmitts than there were Focke-Wulfs.

This video also takes a look at the topic ....

View: https://www.youtube.com/watch?v=AMYpcegvt50

Too many, indeed, up to 7 guns were envisioned. AIrcraft was too heavy for it's small wing (barely bigger thaan on the 109), with the heavy DB 603 in the nose, such a heavy battery of guns & ammo, fuel tankage need to be big...
I'd probably go with a lighter DB 605 instead the 603, and indeed with a reduced weapon setup.

In the light of the Herbert K. Weiss armament report I quoted above, I'd say the Fw 190 had excellent firepower against bombers, and the Me 109 could easily leave the job of shooting down bombers to that type while concentrating on providing protection for the Focke-Wulf - a role in which it could make do with less firepower. A MG 151/20 on the centreline, firing mine shell ammunition, was quite a potent weapon against fighters, and the MK 108 that was later introduced could pretty reliably blow up a fighter with a single hit. Not that I'm opposed to a firepower increase, but I believe we both agree that the Me 109 was limited by engine power in the amount of weaponry it could carry, and perfomance was the more important when engaging enemy fighters than firepower.

Regards,

Henning (HoHun)

 

[tomo pauk]

You might be right. A friend of mine looked into this a couple of years back, and was surprised that the best overview of Me 209 development he could find was written by no-one less than Martin Caidin!

Please, do tell

 

[HoHun]

Hi Tomo,

You might be right. A friend of mine looked into this a couple of years back, and was surprised that the best overview of Me 209 development he could find was written by no-one less than Martin Caidin!

Please, do tell

Well, Caidin has a short chapter on Me 109-related projects in his "Me 109". The German edition messes up the engine designations a bit, but unlike the Wikipedia articles on the Me 209, Caidin actually provides the date of the first flight of the Me 209V5, November 3rd, 1943. According to Caidin, the plane flew with a DB 603A at first, but was upgraded to a DB 603G a couple of days later, though the DB 628 two-stage engine had been the power plant originally intended for it. The Me 209V6 was powered by a Jumo 213A instead, but apparently flew only months later.

If the Wikipedia is correct in stating that the Me 209 was cancelled in August 1943, poor performance in flight tests really can't have been the reason for that. I believe Messerschmitt convinced Hitler to allow the continuation of the program, but according to the Wikipedia, the decison on the cancellation was made final in December 1943. I'd say even that is so shortly after the first flight of the type that one couldn't realistically have expected to have a true picture of the type's full potential.

According to a comparative estimate from March 1944, the Me 209 with DB 603G was expected to have a speed of 730 km/h @ 8500 m at climb and combat power (so that's not absolute top speed), which isn't too shabby. However, the same datasheet also shows the Me 262 with a top speed of 874 km/h at the same altitude ...

Regards,

Henning (HoHun)

 

[T. A. Gardner]

Now, this is reading between the lines somewhat, in Monogram Close Up 24 there is some discussion about the Me 209 as it relates to the Höhenjäger requirement by the RLM. This called for a high-altitude fighter and Messerschmitt's initial proposal, the Me 155 (handed over to BuV for further developement) as supplanted by a proposal for a high-altitude version of the Me 209. This went forward as the Me 209A-4 powered by a DB 628 engine. This was submitted to the RLM in Mid-1943.
This plane would be a direct competitor to the Focke Wulf Ta 153. Both the Me 209 and Ta 153 in these proposed configurations were cancelled in the fall of 1943 and replaced by new proposals as the Ta 152H and Me 209A-4 (confusing huh?)

The Me 209A-4 was to use the DB 628 engine, and detail design drawings were finished on October 25, 1943. The DB 605A or AS engine with nitrous power boost was proposed as an alternative if the DB 628 wasn't available. It appears that design continued even as the program was cancelled.

About two months later, Hitler reinstated the Ta 153 / Me 209 program and on 3 Nov 1943 the Me 209 V5 (SP+LJ) flew for the first time with Fritz Wendel piloting. Fitted with a DB 603, the results were satisfactory but pedestrian. Then on January 13, 1944 the program was cancelled a second time.

The Me 209A-4 was supposed to fly in February but Allied bombing damaged some of the components going into the plane. Messerschmitt decided to modify the Me 209V5 that was cancelled earlier to meet the high-altitude requirement. This aircraft became the Me 209H-1 and was to have the DB 627B engine fitted (2,000 hp), but Daimler-Benz couldn't get the engine to work right so...

Messerschmitt adapted the Me 109H wing (43' 6") to this prototype and it was dubbed the Me 209HV1 and had a four-blade prop fitted, along with leading edge radiators in the wing roots just outboard of a cannon compartment. The Me 209HV1 was ready sometime in April 1944 but problems continued to plague the program and if it was flown and what the results were are unknown.

It sounds like the original Me 209 replacement for the Me 109 series was cancelled fairly early on as unpromising and that Messerschmitt kept the 209 program going on a shoestring as an alternative to the Ta 152-153 program. Given the above, it's likely the whole program was dropped sometime in mid to late 1944 as the Ta 152H started to enter service. I could see Messerschmitt being told to put all effort into the Me 262 program instead of an iffy competitor to the Ta 152H.

 

[tomo pauk]

Thank you for all the input.
We (you) are beating the Wikipedia article massively

 

[tomo pauk]

FWIW: I've asked about the 209 mod.1943 (a.k.a. 209-II) at another forum, the replies are worth to read: link

My own conclusion about the 209 pertinent for this thread: have MTT do a jet fighter after the Bf 109. Any other model of for the day-fighter role is a waste of resources.

 

[Desertfox]

If we want more jet fighter sooner, why not keep the He280 and the HeS 8 and HeS 30 going instead?

 

[tomo pauk]

If we want more jet fighter sooner, why not keep the He280 and the HeS 8 and HeS 30 going instead?

It would've give a fighting chance to the LW in late 1943-early 1944.

 

[T. A. Gardner]

If we want more jet fighter sooner, why not keep the He280 and the HeS 8 and HeS 30 going instead?

Because Henkel could never work out the fuel leakage / fire issue along with continued issues with the compressor section on the HeS 8 (001) engine, while the Wagner-Müller HeS 30 (006) was another over-engineered POS as all of his designs were at the time. For example, the HeS 30 was to use adjustable veins on the turbine rotor, a totally unworkable proposition. This was done in an attempt to shortcut problems with the compressor-turbine mismatch that were occurring.

To be fair, this was an issue for all German turbojets at the time, largely due to Germany's aircraft industry having limited experience with gas turbines and once the war started limited access to companies that did have such experience. In Britain and the US the companies that led the turbojet revolution were mostly ones that had vast experience with gas and steam turbines like, Vickers and General Electric. Thus, they had less issue getting turbine and compressor blade profiles that worked together.

For the 006 it wasn't until early 1943 that most of the issues had been worked out but Henkel was persuaded to drop the 001 and 006 in development due to their small size and limited potential for upgrading for the much larger 011 engine instead.

As for the He 280, the plane was really too small for a jet fighter. Its fuel supply was more in line with piston engine planes rather than fuel hungry turbojets, limiting range. The armament was also limited by the small size of the nose. Then the Germans would have to work out who'd make it since Henkel didn't have the spare capacity to go into mass production with it.

 

[Lascaris]

I'm short of surprised no mention at all is made to the Axis minor allies and Italy here. Just a few thoughts in no particular order.

1. Hungary is the sole one were the Germans made their agreement with with Manfred Weiss to locally produce aircraft. So improvements are more on the types frex producing single engined aircraft in place of Me-210. Did Hungary produce engines locally if not why when they did have engine production capacity?

2. Romania received too little industrial support too late. Give it a license for BMW-801 which the Romanians asked for and did not get apparently, with it IAR-80 stays competitive. If that is not practical give DB-605 early. Post that Germany has more machine tools than the rest of the world combined at the time. Don't need very many to improve Romanian production capacity notably.

3. Italy. I'm not entirely certain if the Germans could help with technical issues that delayed license production of DB-601 but the agreement to license build DB-605 was made in late 1941 IMS? Advance it to mid or early 1941, bringing mass production to some point in 1942. With DB-605 do a reverse transfer, the sought after Bf-109 replacement is Fiat G-55 and since the Germans DID want to buy/produce it...

4. Bulgaria. It's aircraft industry while small existed... and was outright refused license production the Bulgarians were asking for like Avia B135. Makes little sense to me. Scratch that makes no sense to me.

Last while we are into industrial standardization, I seem to recall Jumo 211 was overproduced with something to the tune of 10,000 engines left unused? If I remember correctly and this is accurate the obvious question is where could you use these engines to free up DB engines for other uses?

 

[Calum Douglas]

Similar to the post-BoB RAF: what might've Luftwafe/RLM do after Autumn of 1940 in order to improve their standing, both in short-term (next 12 months) and long-term (a few next years). I've also included 'Axis' term here - mostly European Axis countries' air forces/services - since they can be either drain on German resources, or a benefit.
Changes in strategy, tactics, logistics, hardware etc. Attack on Soviet Union, DoW on USA - all happen as per historically.

(killing Goering, Hitler etc. is an old joke)

I`d say they tried to do what their best bet was, which was going to smash russia, then come back for England later.

So I`d say the problem is in the detailed execution of Barbarossa, and not really a change in the "Grand Strategic" plan.

I must admit to not being much of an expert on the ground campaign, but it appears to be to be possible, if well executed to suceed.

As far as aircraft goes I`d be cancelling the Bf109 immidiately and switching all effort to Fw190 production and Me262, and cancelling almost every other aircraft. Slighty better high altitude performance of the 109 is irrelevant on the Eastern Front (certainly at first). From engine perspective all the mad projects need to end immidiatley, Jumo222, all the DB coupled engines, and I`d also turn DB and Jumo into a conglomerate, run out the last needed 605`s until the 213 is ready (hopefully sooner with both firms working on it). Then get the 190-D9 with Jumo going and get BMW on their turbojets for the 262, having cancelled all their mad 802/803 stuff.

You could shuffle about who/does/what a bit, but thats one reasonable way forward.

 

[tomo pauk]

1. Hungary is the sole one were the Germans made their agreement with with Manfred Weiss to locally produce aircraft. So improvements are more on the types frex producing single engined aircraft in place of Me-210. Did Hungary produce engines locally if not why when they did have engine production capacity?

2. Romania received too little industrial support too late. Give it a license for BMW-801 which the Romanians asked for and did not get apparently, with it IAR-80 stays competitive. If that is not practical give DB-605 early. Post that Germany has more machine tools than the rest of the world combined at the time. Don't need very many to improve Romanian production capacity notably.

Indeed, a more focused co-operation at least eases the burden to the Luftwaffe to act as a fire brigade.
M-W might be better used if they make Fw 190s? Historically, they produced 1210 of DB-605s from late 1942 until 1945 - more than Fiat.
Good call for Romania. They've mooted the Jumo 211-powered IAR-80 that went nowhere?

3. Italy. I'm not entirely certain if the Germans could help with technical issues that delayed license production of DB-601 but the agreement to license build DB-605 was made in late 1941 IMS? Advance it to mid or early 1941, bringing mass production to some point in 1942. With DB-605 do a reverse transfer, the sought after Bf-109 replacement is Fiat G-55 and since the Germans DID want to buy/produce it...

4. Bulgaria. It's aircraft industry while small existed... and was outright refused license production the Bulgarians were asking for like Avia B135. Makes little sense to me. Scratch that makes no sense to me.

Bulgaria - perhaps best bet is simply buy German stuff?
Italy - ship the captured tooling from H-S and G&R to Italian factories (A-R, Fiat, Piaggio)?

Last while we are into industrial standardization, I seem to recall Jumo 211 was overproduced with something to the tune of 10,000 engines left unused? If I remember correctly and this is accurate the obvious question is where could you use these engines to free up DB engines for other uses?

The 10000 pcs of the 211s seem too excessive to me. Eg. the Ju-352 was cancelled due to the lack of Jumo 211s. At any rate, production of Jumo engines was switching to the Jumo 213 by early 1944.

 

[HoHun]

Hi Calum,

As far as aircraft goes I`d be cancelling the Bf109 immidiately and switching all effort to Fw190 production and Me262, and cancelling almost every other aircraft.

Hm, didn't you point out in "The Secret Horsepower Race" that the Germans historically capped the Fw 190 strength to a more or less moderate total due to limited availability of C3 fuel? I thought that was a really interesting insight!

Regards,

Henning (HoHun)

 

[tomo pauk]

As far as aircraft goes I`d be cancelling the Bf109 immidiately and switching all effort to Fw190 production and Me262, and cancelling almost every other aircraft. Slighty better high altitude performance of the 109 is irrelevant on the Eastern Front (certainly at first). From engine perspective all the mad projects need to end immidiatley, Jumo222, all the DB coupled engines, and I`d also turn DB and Jumo into a conglomerate, run out the last needed 605`s until the 213 is ready (hopefully sooner with both firms working on it). Then get the 190-D9 with Jumo going and get BMW on their turbojets for the 262, having cancelled all their mad 802/803 stuff.

Indeed, cancel the 'mad stuff'.
Bf 109, on the other hand? Luftwaffe needs something to flesh out it's fighter units in 1941. Fw 190 is not yet ready, mostly due to the engine woes. Bf 109F/G is longer-ranged than Fw 190A, range is necessary to cover vast expanses of Soviet Union, Mediterranean and N. Africa. Better fuel mileage is less taxing to the German fuel reserves.
Bf 109 provided the superiority against what VVS flew, was well as what RAF flew in N.Africa. It was a reason to the huge losses of VVS fighters trying to intercept the German bombers. So if we want to axe aircraft type(s) from MTT, the Me 210 and 163 are at the top of the list. He 177 begs for the axe. Hs 129, despite all the hype? Hs 126 certainly.
As for the engines - how bad would've been a DB 601/605 with a big S/C, let alone with 2-stage S/C, but with timeline for these engines 'pushed' earlier by 12-15 months vs. historically?

I'd agree with suggestion that Fw 190 gets higher (highest?) priority, and will toss the favorite idea of mine, namely that DB 601/605 is also the engine for Fw 190.

 

[tomo pauk]

Hm, didn't you point out in "The Secret Horsepower Race" that the Germans historically capped the Fw 190 strength to a more or less moderate total due to limited availability of C3 fuel? I thought that was a really interesting insight!

The BMW 801C-powered Fw 190 was still a zippy aircraft, used the B4 fuel.

 

[tomo pauk]

Calum posted the DB engine production data here: link.

 

[HoHun]

Hi Tomo,

Hm, didn't you point out in "The Secret Horsepower Race" that the Germans historically capped the Fw 190 strength to a more or less moderate total due to limited availability of C3 fuel? I thought that was a really interesting insight!

The BMW 801C-powered Fw 190 was still a zippy aircraft, used the B4 fuel.

I'm not entirely sure what kind of power to expect from the BMW 801C, but as far as I can tell at the moment, it had a reduced full throttle height as well as reduced power. At 6 km and above, it would easily lose 50 km/h on a Fw 190 powered by the BMW 801D, I'd say.

You'd be better off with a Me 109, in my opinion.

Regards,

Henning (HoHun)

 

[tomo pauk]

I'm not entirely sure what kind of power to expect from the BMW 801C, but as far as I can tell at the moment, it had a reduced full throttle height as well as reduced power. At 6 km and above, it would easily lose 50 km/h on a Fw 190 powered by the BMW 801D, I'd say.

We can fight under 6 km (= Eastern Front, Mediterranean), leaving the 801D-powered versions in the West.
FWIW, (and with my remark that these speed figures are perhaps without compressibility accounted for) the 801C-powered Fw 190A-1 and A-2 was still pretty fast, especially if the 801C was run at 2700 rpm in high gear: test report.
The BMW 801C was a fuel hog, though, even when compared with 801D, let alone when compared with DB 601E or 605A.

You'd be better off with a Me 109, in my opinion.

I'd be even better with a Fw 190 powered by DB 601E or 605A.
Retains the good features of the Fw 190, less of engine-related problems in 1941 and 1942, has much better payload/weapon/fuel/range capability than Bf 109.

 

[HoHun]

Hi Tomo,

I'd be even better with a Fw 190 powered by DB 601E or 605A.
Retains the good features of the Fw 190, less of engine-related problems in 1941 and 1942, has much better payload/weapon/fuel/range capability than Bf 109.

I'm not sure of that ... please have a look at the attached calculation. I've used DB 605A data with the Cd0 of a Fw 190D-9, a ram efficiency of 60% and a 200 kg reduction in weight over the radial-powered Fw 190A-5.

Regards,

Henning (HoHun)

 

[tomo pauk]

I'm not sure of that ... please have a look at the attached calculation. I've used DB 605A data with the Cd0 of a Fw 190D-9, a ram efficiency of 60% and a 200 kg reduction in weight over the radial-powered Fw 190A-5.

Thanks for the graphs.
Me - being stubborn as always - am/was expecting the speed figures in-between the MC.205 and Re.2005 on 2600 rpm and 1.3 ata, since the Fw 190 have had the wing size in-between the two (yes, wing drag is not the only determinant of the total drag).
The former did 640-650 km/h, the later did 625-630 (all for 2600 rpm and 1.3 ata), hopefully giving at the end 630-640 km/h for our brave new "Fw 190DB".

 

[HoHun]

Hi Tomo,

Me - being stubborn as always - am/was expecting the speed figures in-between the MC.205 and Re.2005 on 2600 rpm and 1.3 ata, since the Fw 190 have had the wing size in-between the two (yes, wing drag is not the only determinant of the total drag).
The former did 640-650 km/h, the later did 625-630 (all for 2600 rpm and 1.3 ata), hopefully giving at the end 630-640 km/h for our brave new "Fw 190DB".

These might be good reference points, having their origin in radial-engined aircraft as well. However, the Fw 190 really was a brilliant design overall, but it was not a low-drag wonder and really needed an engine as powerful as the one it originally had.

Of course, it might be an interesting exercise to try and track the performance losses from the A-1 to the A-5, maybe that shows the path to higher speeds. On the other hand, most of those losses would have been caused by responding to operational requirements, such as the installation of heavier armament, which one can't quite ignore ...

Maybe the Fw 190B would have been a better basis for a DB605A-powered Focke-Wulf, having shed quite a bit of extra weight in the attempt to achieve high-altitude performance.

Regards,

Henning (HoHun)

 

[tomo pauk]

These might be good reference points, having their origin in radial-engined aircraft as well. However, the Fw 190 really was a brilliant design overall, but it was not a low-drag wonder and really needed an engine as powerful as the one it originally had.

It maybe was not a wonder, but it was a low-drag aircraft when compared with other fighters powered by radial engines, or the Doras when compared with V12-powered fighters. Being small, with fully retractable and covered U/C, as well as the well slanted windscreen = all played the part in shedding the drag to the realistic minimum.

Of course, it might be an interesting exercise to try and track the performance losses from the A-1 to the A-5, maybe that shows the path to higher speeds. On the other hand, most of those losses would have been caused by responding to operational requirements, such as the installation of heavier armament, which one can't quite ignore ...

The guns might need a reassessment.
Eg. the LMGs barely contributed to firepower once the 2, let alone 4 cannons were carried, while adding to drag (not by much). The ammo drum cover for the MG FFM cost some speed. The cowl HMGs were probably the worst - barely making a dent on the aircraft of 1944, yet cost 10+- km/h; the 3 cannon installation on D-12 was less draggy than 2 cannon + 2 HMG on D-9, even though the 30mm was the central cannon. The wing root MG 151/20s will add drag vs. MG 17s in the same space.
Drop tank rack seem to be a ... substantial item sticking out.

A DB-601E/605A powered Fw 190 will do a lot of work even with just 3 MG 151s (or the MG 151/20s combined with MK 108), while not being any slower than a Bf 109F/G with cannons in gondolas.

Maybe the Fw 190B would have been a better basis for a DB605A-powered Focke-Wulf, having shed quite a bit of extra weight in the attempt to achieve high-altitude performance.

Those were supposed to be armed with just 2 cannons, and also lacking protection for fuel tanks?

 

[HoHun]

Hi Tomo,

It maybe was not a wonder, but it was a low-drag aircraft when compared with other fighters powered by radial engines, or the Doras when compared with V12-powered fighters. Being small, with fully retractable and covered U/C, as well as the well slanted windscreen = all played the part in shedding the drag to the realistic minimum.

Hm, the Doras and their drag are a bit enigmatic, but my impression is that they weren't all that much better than the Antons. And accordingly, overall the Me 109 made more speed at the same horsepower, though the Dora was fast because it had more power available (except when comparing special emergency power, perhaps).

The guns might need a reassessment.
Eg. the LMGs barely contributed to firepower once the 2, let alone 4 cannons were carried, while adding to drag (not by much). The ammo drum cover for the MG FFM cost some speed. The cowl HMGs were probably the worst - barely making a dent on the aircraft of 1944, yet cost 10+- km/h; the 3 cannon installation on D-12 was less draggy than 2 cannon + 2 HMG on D-9, even though the 30mm was the central cannon. The wing root MG 151/20s will add drag vs. MG 17s in the same space.

I really wonder why the MGs were kept at all. They might have been desired for strafing, but I'm really puzzled why they weren't made a removable Rüstsatz or something. Two wing-root cannon were plenty of firepower, in a great arrangement close to the centreline ... one shouldn't have needed MGs to go with that, at least not considering the price in drag and weight paid for carrying them. In a time when German engines were behind the curve, eliminating inefficient equipment should have been high on the list of priorities.

A DB-601E/605A powered Fw 190 will do a lot of work even with just 3 MG 151s (or the MG 151/20s combined with MK 108), while not being any slower than a Bf 109F/G with cannons in gondolas.

Well, I believe the MK108 arrived at the scene very late, so you might not want to risk an underpowered aircraft against superior numbers of superior performing Allied fighters. The gondolas were mostly removed from the Messerschmitts too, I believe.

Maybe the Fw 190B would have been a better basis for a DB605A-powered Focke-Wulf, having shed quite a bit of extra weight in the attempt to achieve high-altitude performance.

Those were supposed to be armed with just 2 cannons, and also lacking protection for fuel tanks?

Hermann's book on the Fw 190 Höhenjäger with regard to the Fw 190B states: According to the production planning document dating December 1941, it was scheduled for mass production, starting in June 1942, in parallel to the Fw 190A, for a total of 2991 aircraft until September 1943. Anton output in the same period was to be 1052 aircraft, so the Bertha would have been the primary type.

The Fw 190B-1 was planned to be equipped with:

Enlargend wing of 20.3 m^2 area and 12.3 m span.
External ram-air engine intakes
Pressure cabin - not initially, later to be introduced into the series, 45 kg extra weight
Unprotected fuel tanks for 525 L C3 fuel
Armour - 48 kg engine armour, 16 kg armour glass windscreen. No back armour.
2 MG151 wing root guns
FuG 16 Z

no MG 17 cowl guns
no MG FF wing guns as Rüstsatz
no bomb Rüstsätze installed
apparently, no GM-1 system as it's not listed in the Baubeschreibung

The tank question is a bit puzzling as the capacity is the same as that of the protected tanks. As the "Behälterschutz" (tank protection) is listed under armour, with 50.5 kg, I'm not sure this means the tanks were not self-sealing ... this sounds almost as if the Anton had belly plates normally protecting the fuel tanks. I thought this was a Jabo-specific modification, but I don't really know at the moment. On the other hand, this table lists 20 kg extra fuel, which would come down to about 30 L extra capacity.

The problem with Hermann's book is, it's an editorial mess. On the pages supposed to show the Baubeschreibung from 14 August 1941, there's a data sheet with performance curves dated 28 November 1942 - that really makes me wonder, what else did Hermann mix together? There are certain internal contradiction in the Baubeschreibung chapter, and more controdictions to the chapter about the scheduled series production.

The projected top speed for a fighter apparently equivalent to the by-then canceled Fw 190B-1 in the November 1942 graph is 690 km/h @ 7 km, using take-off/emergency power of the BMW 801D. Using this aircraft as a basis, but increasing weight to 4106 kg like the A-5, and reducing ram efficiency to match the internal intakes on the A-5, I calculate a top speed of 672 km/h vs. the 656 km/h from the data sheet, so the combined effect of the drag reduction from removing nose and outer wing guns and the drag increase from the larger wing was worth 16 km/h speed increase.

There's another performance diagram on page 24, but it's so closely cropped that all the important information necessary for understanding the diagram is missing. That's why I hate Hermann's books ... great sources prevented in a way that makes them close to useless.

The Fw 190B-1 re-engined to the DB605A (and lightened by another 200 kg to account for the lighter engine) would be sort of comparable to the Me 109G using the same engine, I presume. However, Me 109G performance really is a can of worms all of its own (and the Me 109 did have rear armour, so the comparison isn't entirely fair.)

Regards,

Henning (HoHun)

 

[tomo pauk]

Hm, the Doras and their drag are a bit enigmatic, but my impression is that they weren't all that much better than the Antons. And accordingly, overall the Me 109 made more speed at the same horsepower, though the Dora was fast because it had more power available (except when comparing special emergency power, perhaps).

This is the best source wrt. drag of the 190s & 152s that I'm aware of: table.
Table is also quoted by D. Lednicer when he wrote the article about the drag of Fw 190A, 190S, P-51D and Spitfire. The high speed drag (ie. Cd0) is stated as the 'equivalent flat plate', ie. in square meters. The 190A-8 has the 'Schnellflug Cw0' (w = wiederstand = drag; Cw0 = Cd0) value of 0.485 m^2; the 190D-9 is at 0.444. So the A-8 has 10% greater drag than D-9.
Further look at the table shows why the D-9 had lower drag. The section 'Widerstandsenteile' ('drag dsitribution', roughly) notes the greater drag of the fuselage ('Rumpf') and also greater cooling ('Kuehlung') drag of the A-8. Both items were related to the engine type and it's frontal area.
The D-9 also has lower weapon-related drag ('Waffen'; it has two cannons less), something that can further decrease if the HMG installation is avoided all together, replaced by a motor cannon, as seen by the D-12 data in the table.
D-9 has had greater empenage drag, as well as a draggier ram air intake per table.

I really wonder why the MGs were kept at all. They might have been desired for strafing, but I'm really puzzled why they weren't made a removable Rüstsatz or something. Two wing-root cannon were plenty of firepower, in a great arrangement close to the centreline ... one shouldn't have needed MGs to go with that, at least not considering the price in drag and weight paid for carrying them. In a time when German engines were behind the curve, eliminating inefficient equipment should have been high on the list of priorities.

Agreed all the way.

Well, I believe the MK108 arrived at the scene very late, so you might not want to risk an underpowered aircraft against superior numbers of superior performing Allied fighters. The gondolas were mostly removed from the Messerschmitts too, I believe.

Engines (or, their altitude power) needs indeed to be sorted 1st. That, along with introduction of jet fighters.
The '190 DB' will still be plenty enough to work at Eastern front, in any time between 1941-45.

The Fw 190B-1 was planned to be equipped with:

Enlargend wing of 20.3 m^2 area and 12.3 m span.
External ram-air engine intakes

The external ram-air intake was really the low-hanging fruit for the Fw 190 series. Those were offering +15 km/h at 7-8 km, and still +10 km/h at 9-10 km of altitude (these intakes were also draggier, so at lower altitude the speed was slightly decreased). RoC was also improved.
The only change was the type of cowling, that was later used when filters were needed for the Jabo 190s.

 

[HoHun]

Hi Tomo,

The 190A-8 has the 'Schnellflug Cw0' (w = wiederstand = drag; Cw0 = Cd0) value of 0.485 m^2; the 190D-9 is at 0.444. So the A-8 has 10% greater drag than D-9.
Further look at the table shows why the D-9 had lower drag. The section 'Widerstandsenteile' ('drag dsitribution', roughly) notes the greater drag of the fuselage ('Rumpf') and also greater cooling ('Kuehlung') drag of the A-8. Both items were related to the engine type and it's frontal area.
The D-9 also has lower weapon-related drag ('Waffen'; it has two cannons less), something that can further decrease if the HMG installation is avoided all together, replaced by a motor cannon, as seen by the D-12 data in the table.
D-9 has had greater empenage drag, as well as a draggier ram air intake per table.

Hm, I hadn't looked at that table for a long time. There's a second table (attached), which looks like it might belong to the drag table since it follows the same structure, but the date is two months earlier, and the flying weights don't quite match.



Using the performance data from the second table, here a comparison between the drag table values and those I calculated:

Type - Drag Table - My value

Fw 190A-8 - 0.485 - 0.475
Fw 190D-9 - 0.444 - 0.435

However, in addition to the data basis for performance and drag data probably being different, my values might also deviate from the drag table values because if you work from top speeds, the exact results depends a lot on the engine curve, and what effects you take into account when computing in-flight performance from the static power curves, not to mention the hard-to-find exhaust thrust curves.

Especially the Jumo 213A data was subject to continuous revision, and if the power graph isn't exactly the same Focke-Wulf used for their calculations, my drag value is going to be different. In combination with the power graph, I still can make quite realistic performance estimates anyway, as the known top speed values serve as calibration points.

People often consider zero-lift drag coefficients a bit of the holy grail, but they don't really exist independendly of the calculation formulae, and to a certain degree are artifacts of the mathematical modelling you use. If you've seen Dr. Hoerner's drag analysis of the Me 109, you can see that he works his way backwards from a top speed and an assumed engine power/exhaust thrust combination as well, and of course, these affect the exact value for Cd0 he ends up with.

The external ram-air intake was really the low-hanging fruit for the Fw 190 series. Those were offering +15 km/h at 7-8 km, and still +10 km/h at 9-10 km of altitude (these intakes were also draggier, so at lower altitude the speed was slightly decreased). RoC was also improved.

Well, I'm not sure ... I think there are several reports on them that don't all agree on their effectiveness and efficiency. Maybe they were not introduced because the reports were they looked worse were the more realistical ones.

Still, the failure to exploit ram effect to a greater degree looks very much like a missed opportunity, and it's worth noting that many years ago, Flugzeug Classic published a photograph of what I think might have been a prototype for the Fw 190A-10 that showed ram air intakes for the BMW 801 that were integrated into the wing roots (protuding forward a bit, so I'm not sure the air actually entered the original wing). I thought that this could be seen as an indication that the cheek intakes weren't really such a good solution.

Regards,

Henning (HoHun)

 

[tomo pauk]

Using the performance data from the second table, here a comparison between the drag table values and those I calculated:

Type - Drag Table - My value

Fw 190A-8 - 0.485 - 0.475
Fw 190D-9 - 0.444 - 0.435

Thank you.
The ~10% advantage for the D-9 can be noted per both data sets. We might recall that a 10% improvement in drag nets a greater speed advantage than a 10% increase of engine power. The D-9 is notably faster with 'Kampfleistung' (~1480 PS at 6.6 km) than the A-8 with 1440 PS at 6.3 km ('Notleistung').

However, in addition to the data basis for performance and drag data probably being different, my values might also deviate from the drag table values because if you work from top speeds, the exact results depends a lot on the engine curve, and what effects you take into account when computing in-flight performance from the static power curves, not to mention the hard-to-find exhaust thrust curves.

Pinning down the exact drag value is not the kind of math I'm favoring - there is a lot of other people and original data for me to read, rather than to compute
Some exhaust thrust curves are easy to find: Jumo 213A ; BMW 801D
Long story short: Jumo 213A have had 145-150 kg of exhaust thrust at 5.7 km, where the BMW 801D had 120 kg. It also had about 100 PS more at 5.7 km than BMW 801D's 1440 PS. Jumo 213A as-installed also used the ram effect better due to the non-restricted intake, 'elevating' the rated altitude by ~1000m, vs. ~600m for the BMW 801D with 'normal' intakes.

People often consider zero-lift drag coefficients a bit of the holy grail, but they don't really exist independendly of the calculation formulae, and to a certain degree are artifacts of the mathematical modelling you use. If you've seen Dr. Hoerner's drag analysis of the Me 109, you can see that he works his way backwards from a top speed and an assumed engine power/exhaust thrust combination as well, and of course, these affect the exact value for Cd0 he ends up with.

Hoerner's calculation takes in account, unfortunately, the draggiest Bf 109.
His top speed figure of just 610 for 1200 PS at 22000 ft, provided by DB 601A (sic!) is ~15 km/h lower than what GL/C sheet gives for 'Kampfleistung' power setting for the G-6.

Cd0 is not be all end all, but it is more than just a good start. It does favor aircraft with big wings, though, the Bf 109 was not such an A/C.

 

[HoHun]

Hi Tomo,

The ~10% advantage for the D-9 can be noted per both data sets. We might recall that a 10% improvement in drag nets a greater speed advantage than a 10% increase of engine power.

Agreed, the absolute values aren't that important actually.

Pinning down the exact drag value is not the kind of math I'm favoring - there is a lot of other people and original data for me to read, rather than to compute

Well, the original data was only computed anyway, based on tests that were conducted with real-life engine whose altitude performance, due to production variance, you couldn't actually establish with great accuracy. Few engines used for performance tests were even bench-tested for performance, and calculating altitude performance from bench-test performance was difficult too. So the drag table data, while original, is not necessarily more accurate or more useful than data we can compute for ourselves.

Some exhaust thrust curves are easy to find: Jumo 213A ; BMW 801D

You're right, but these have only been available online for 15 years or so The Jumo 213A graph certainly was very welcome when first published! I've been using these values for my own calculations, so these should not be the reason for the difference between the drag table and my calculated values. However, such power curves were frequently revised, so the drag table data might have been based on a different revision.

In more general terms, such curves are really rare though - I've not seen similar gaphs for engines from other countries than Germany, though a few Merlin data points are provided by Hooker's "Performance of the Supercharged Aero-Engine". And even for German engines, power graphs showing only shaft power, but not exhaust thrust, are the rule rather than the exception.

Hoerner's calculation takes in account, unfortunately, the draggiest Bf 109.
His top speed figure of just 610 for 1200 PS at 22000 ft, provided by DB 601A (sic!) is ~15 km/h lower than what GL/C sheet gives for 'Kampfleistung' power setting for the G-6.

Yes, and he has chosen some nice round values for making a textbook example to teach the analysis method, I don't think it was even meant to be accurate (though it certainly is realistic). He probably also meant to impress on his pupils the value of meticulous attention to aerodynamic detail.

Regards,

Henning (HoHun)

 

[tomo pauk]

You're right, but these have only been available online for 15 years or so The Jumo 213A graph certainly was very welcome when first published! I've been using these values for my own calculations, so these should not be the reason for the difference between the drag table and my calculated values. However, such power curves were frequently revised, so the drag table data might have been based on a different revision.

In more general terms, such curves are really rare though - I've not seen similar gaphs for engines from other countries than Germany, though a few Merlin data points are provided by Hooker's "Performance of the Supercharged Aero-Engine". And even for German engines, power graphs showing only shaft power, but not exhaust thrust, are the rule rather than the exception.

The exhaust thrust chart for the Jumo 213E can be seen here. Please note that this is with 'Sondernotleisung' restricted just for the 1st two S/C speeds.
Expressed here in horespower equivalent is the exhaust thrust ('Strahlleistungen in PS') of the DB 601A at 600 km/h, maxing at about 120-130 PS at 4.5 km. From what I can gather from there, a well-executed exhaust on the engine of the day adds the horsepower equivalent of ~10% at 3 km of altitude, and ~15% at 7 km.
Not bad, for what is basically 'free power'.

 

[Pioneer]

tomo pauk said:
A DB-601E/605A powered Fw 190 will do a lot of work even with just 3 MG 151s (or the MG 151/20s combined with MK 108), while not being any slower than a Bf 109F/G with cannons in gondolas.

With respect, from all that I've read over the years, as powerful as the MK 108 30mm cannon was against allied bombers, it was not as effective against allied fighters because of it's lower rate of fire when compared to the 20mm. As much as it's true that most of the Luftwaffe's priority was to engage and destroy allied bombers by this stage of the war, their fighters still needed to contend with the ever growing number of allied long-range escort fighters. So, I would think the MG 151/20 would have been the better jack of all trades weapon.

Regards
Pioneer

 

[tomo pauk]

tomo pauk said:
A DB-601E/605A powered Fw 190 will do a lot of work even with just 3 MG 151s (or the MG 151/20s combined with MK 108), while not being any slower than a Bf 109F/G with cannons in gondolas.

With respect, from all that I've read over the years, as powerful as the MK 108 30mm cannon was against allied bombers, it was not as effective against allied fighters because of it's lower rate of fire when compared to the 20mm. As much as it's true that most of the Luftwaffe's priority was to engage and destroy allied bombers by this stage of the war, their fighters still needed to contend with the ever growing number of allied long-range escort fighters. So, I would think the MG 151/20 would have been the better jack of all trades weapon.

Regards
Pioneer

Please note that alternative LW airborne guns were also suggested in this thread. I'd favor the in-between 30mm cannon, ie. something mid-way between the low MV MK108 and high MV MK 103. Talk 700+ m/s vs. 500 for the MK108 and 900+- for the MK103.
Alternatively, a 23-25mm weapon perhaps?

 

[Pioneer]

tomo pauk said:
A DB-601E/605A powered Fw 190 will do a lot of work even with just 3 MG 151s (or the MG 151/20s combined with MK 108), while not being any slower than a Bf 109F/G with cannons in gondolas.

With respect, from all that I've read over the years, as powerful as the MK 108 30mm cannon was against allied bombers, it was not as effective against allied fighters because of it's lower rate of fire when compared to the 20mm. As much as it's true that most of the Luftwaffe's priority was to engage and destroy allied bombers by this stage of the war, their fighters still needed to contend with the ever growing number of allied long-range escort fighters. So, I would think the MG 151/20 would have been the better jack of all trades weapon.

Regards
Pioneer

Please note that alternative LW airborne guns were also suggested in this thread. I'd favor the in-between 30mm cannon, ie. something mid-way between the low MV MK108 and high MV MK 103. Talk 700+ m/s vs. 500 for the MK108 and 900+- for the MK103.
Alternatively, a 23-25mm weapon perhaps?

I would think that German war industry would be at its wits end, having to re equip to manufacture and facilitate another cannon round by this stage of the war. Logistically commonality of manufacturing was the name of the game as far as Albert Speer was concerned.

Regards
Pioneer

 

[HoHun]

Hi Pioneer,

With respect, from all that I've read over the years, as powerful as the MK 108 30mm cannon was against allied bombers, it was not as effective against allied fighters because of it's lower rate of fire when compared to the 20mm.

Well, Tony Williams has the MG 151/20 at 12 rounds per second, and the MK 108 at 10 rps, so the difference really is nothing to write home about:

WORLD WAR 2 FIGHTER GUN EFFECTIVENESS

At the same time, the MK108 shell has about 4 times the destructive power of the MG 151/20's, so it's clearly a more effective weapon.

Tony in "Rapid Fire" (or maybe "Flying Guns") also mentions British trials to establish the effect of the MK 108 shell on target aircraft, using derelict Spitfire and Blenheim airframes. If I remember the data correctly, 9 out of 10 Spitfires were certain kill from a single MK 108 round, the last one was a probable. With regard to the Blenheim, I believe there were "only" 7 certain kills from a single round, and I'm not sure if there was any one in the remaining 3 that was not considered a "probable".

In any case, against fighters the MK 108 had a very high probability of a kill with a single hit, so a rate of fire giving 9 or 10 chances of that sort every second isn't what I'd consider an indication of an "ineffective" gun

Regards,

Henning (HoHun)

 

[HoHun]

Hi Tomo,

Please note that alternative LW airborne guns were also suggested in this thread. I'd favor the in-between 30mm cannon, ie. something mid-way between the low MV MK108 and high MV MK 103. Talk 700+ m/s vs. 500 for the MK108 and 900+- for the MK103.

Muzzle velocity is not a big deal, as you either have a non-manoevring target, which you can shoot at medium ranges with good chances of success regardless of muzzle velocity, or a manoeuvring target, which requires you to close to a very short range anyhow.

If you're closing to short range with a manoeuvring target, it's no longer just range that's a problem, but geometry as well, as you have to achieve a firing solution that you can sustain for a long enough time to actually destroy the target.

If you have a low-velocity cannon capable of destroying a target with a single hit, this problem is actually easier to solve than with a high-velocity gun that requires a lot more hits, as you can achieve the single hit even with a brief firing solution, such as when momentarily pointing the nose at the target, while for a lower-firepower weapon, you are pretty much forced to fly yourself into a position that gives you a sustained tracking shot.

Everything else staying the same, a higher muzzle velocity is obviously preferrably, but realistically, you'd have to make some compromises to build a gun to replace the MK 108, but using the same technology as the MK 108. If you sacrifice shell size to raise muzzle velocity, you might gain a 20% increase in hit probability for a 40% decrease in probability of kill, for example ... that would not be an improvement, overall. If you raise muzzle velocity using the same shells, you might end up decreasing rate of fire while increasing weapon weight ... that's the path from the MK 108 to the MK 103. Again, the original MK 108 was the better weapon for fighters, overall.

Not to say it would impossible to come up with a better 30 mm cannon than the MK 108, but I wouldn't expect any great leap ahead even in the best of cases. In the "post Battle of Britain" context, I would rather try to get the MK 108 into service earlier, instead of risking delaying the introduction of a new cannon by trying to build a different weapon instead.

Regards,

Henning (HoHun)

 

[tomo pauk]

I would think that German war industry would be at its wits end, having to re equip to manufacture and facilitate another cannon round by this stage of the war. Logistically commonality of manufacturing was the name of the game as far as Albert Speer was concerned.

The mid-power 30mm needs to be in service at least by Spring of 1943. That probably means no MK 108 and no MK 103 - fine by me.