AHC: the ideal fighter(s) for 1940

Compared to other 20s the MG FF was extremely light and limited to a drum magazine in 1940. However the remove of it's 26kg per wing, not counting ammo, was a significant help. Two MG 17s were lighter than 1 MG FF. The Bf109F's maneuverability enhancements weren't limited to just the removal of armament from the wings, but that was a factor (including the redesign of the wings...but why not the cockpit?). Yes, the 20mm mine shell will kill anything it hits in 1940...the problem is getting it to hit relative to the fire rate and velocity of the regular MG round, which was still quite lethal with multiple hits against a fighter.
A twined MG 81Z is less than half the weight of a MG FF.

Targets of the LW fighters were not exclusively fighters, that includes year of 1940. Cannon can kill bombers and fighters, MGs are less than great in killing the bombers. Two 26 kg MG FFMs are still just as heavy as a single Hispano, while offering twice the rate of fire, and not too heavy for 1000+ HP engine on a monoplane with retractable U/C in 1940. We know that 1st thing people were complaining on the Bf 109F (after the wing & tail problems), was reduction of firepower.
LMG vs. cannon will always offer light weight and RoF, while single LMG it will not match 10% of cannon's destructive power.

With that said - this thread is about ideal fighters (like best possible with then-current tech available) rather than how to improve Bf 109. Thus my proposal for the LW in shape of the V12 powered Fw 190 with the initial small wing, featuring 2 cannons and 4 LMGs, with many advantages vs. a tweaked Bf 109 and far less restrictions.
 
When was the 13mm MG 131 introduced? Would it make sense to replace the MG 17s in the cowl of the FW-190 with these (as was done in later versions) and keep the MG 151/20s in the wing roots? Two 13mm MGs plus two 20mm Autocanons sounds about as good as you can get without added under-wing pods or modifying the wing to house additional guns internally.
 

Deleted member 1487

When was the 13mm MG 131 introduced? Would it make sense to replace the MG 17s in the cowl of the FW-190 with these (as was done in later versions) and keep the MG 151/20s in the wing roots? Two 13mm MGs plus two 20mm Autocanons sounds about as good as you can get without added under-wing pods or modifying the wing to house additional guns internally.
I've seen 1941 on German language sites. English wikipedia say 1940.

Targets of the LW fighters were not exclusively fighters, that includes year of 1940. Cannon can kill bombers and fighters, MGs are less than great in killing the bombers. Two 26 kg MG FFMs are still just as heavy as a single Hispano, while offering twice the rate of fire, and not too heavy for 1000+ HP engine on a monoplane with retractable U/C in 1940. We know that 1st thing people were complaining on the Bf 109F (after the wing & tail problems), was reduction of firepower.
LMG vs. cannon will always offer light weight and RoF, while single LMG it will not match 10% of cannon's destructive power.

With that said - this thread is about ideal fighters (like best possible with then-current tech available) rather than how to improve Bf 109. Thus my proposal for the LW in shape of the V12 powered Fw 190 with the initial small wing, featuring 2 cannons and 4 LMGs, with many advantages vs. a tweaked Bf 109 and far less restrictions.
Ideal for what threat? The perfectly balanced fighter for all threats yes, for the threats a side is likely to face in 1940 then anti-fighter armament is probably better. The problem with the MG FF is low muzzle velocity and low ammo capacity, which hampers it's ability to score hits. No one is going to argue that it wasn't destructive when it hit, the issue is scoring the hits. Well placed MG 81Z bursts with explosive ammo is going to do the job on pretty much all 1940 aircraft; in some ways the MG FF is overkill for the task until 1941 and beyond when the heavies show up.
 
I've seen 1941 on German language sites. English wikipedia say 1940.
So probably not an option for our limitations (1940). I generally agree with @tomo pauk, getting the FW-190 operational in 1940 by any means would give the LW the best possible fighter they could get at the time. The only question is, How? Re-engineering for a V-12 is one possibility although just simply abandoning the fully enclosed "streamlined" cowl on the original radial may be even simpler. Drop that concept a few months earlier and you could have the V5g building in spring of 1940 (rather than late summer/early autumn) and get orders for the FW-190A-0 by Summer. Stick with the original armament of two synchronized MG 17s in the cowl, two synchronized MG 151/20s in the wing roots, and two free-firing MG 17s in the outer wings and you have an absolute beast for the BoB.
 
When was the 13mm MG 131 introduced? Would it make sense to replace the MG 17s in the cowl of the FW-190 with these (as was done in later versions) and keep the MG 151/20s in the wing roots? Two 13mm MGs plus two 20mm Autocanons sounds about as good as you can get without added under-wing pods or modifying the wing to house additional guns internally.

Seven examples of the MG 131 were tested from 1938 on at Trevemuende. In 1940 the weapon was cleared for series production. Tony Williams stated that it was 1941 when the MG 131 started appearing in flexible installations, and as regular fixed wepapon from 1943 on.
MG 131 installation, with the extra 'roof' above the weapon, was 'guilty' for a 7-10 km/h loss on the Fw 190s where it replaced MG 17s.

So probably not an option for our limitations (1940). I generally agree with @tomo pauk, getting the FW-190 operational in 1940 by any means would give the LW the best possible fighter they could get at the time. The only question is, How? Re-engineering for a V-12 is one possibility although just simply abandoning the fully enclosed "streamlined" cowl on the original radial may be even simpler. Drop that concept a few months earlier and you could have the V5g building in spring of 1940 (rather than late summer/early autumn) and get orders for the FW-190A-0 by Summer. Stick with the original armament of two synchronized MG 17s in the cowl, two synchronized MG 151/20s in the wing roots, and two free-firing MG 17s in the outer wings and you have an absolute beast for the BoB.

I'd go for the V12-powered Fw 190 from the get go. Let's use the Jumo 211 initially in order to circumvent the need for the DB 601, the power egg installation should make the job easier both for design and production phase. Jumo 211 weights less than BMW 139 or 801, so the initial small wing can be retained (again speeds up development and production).
Original armament of the Fw 190 prototypes was two MG 17s and two MG 131s, all in wing roots; no cowl guns. I'd go with wing-mounted MG FF, later FFM, and four MG 17s in the roots.
MG 151/20 is too late for 1940.
 
Ideal for what threat? The perfectly balanced fighter for all threats yes, for the threats a side is likely to face in 1940 then anti-fighter armament is probably better. The problem with the MG FF is low muzzle velocity and low ammo capacity, which hampers it's ability to score hits. No one is going to argue that it wasn't destructive when it hit, the issue is scoring the hits. Well placed MG 81Z bursts with explosive ammo is going to do the job on pretty much all 1940 aircraft; in some ways the MG FF is overkill for the task until 1941 and beyond when the heavies show up.

'Ideal' in a sense that it can offer competitive performance and maneuverability, along with excellent visibility, range, rate of roll and firepower.
MG FF was with low MV, the MG FFM was with decent MV at almost 700 m/s. The MG 131 was barely better at 710-750 m/s, depending on the ammo.
I'm not sure that anyone reckoned the MG FF(M) as overkill in any time. MG 81Z with explosive ammo will not get us anywhere.

Plenty about the MG 131, the pdf docs describing development are at the bottom of the page: link.
 

Deleted member 1487

I'd go for the V12-powered Fw 190 from the get go. Let's use the Jumo 211 initially in order to circumvent the need for the DB 601, the power egg installation should make the job easier both for design and production phase. Jumo 211 weights less than BMW 139 or 801, so the initial small wing can be retained (again speeds up development and production).
The problem with the Jumo 211 in 1940 was lack of ability to do 'sprints' like the BD601/5 and lack of pressurized cooling, which impaired it's performance at higher altitudes. That's not a problem for bombers as much in the period, but is a huge problem for fighters.
https://en.wikipedia.org/wiki/Junkers_Jumo_211
The resulting Jumo 211 was first prototyped at Jumo's Dessau plant in 1935 and started testing in April 1936. Like the 210H, it featured a mechanical direct fuel injection system using small pistons driven off the crankshaft, three valves per cylinder, and an inverted V layout. It also had an open-cycle cooling system, not pressurized, as was the case on the later 213.[2]

A major upgrade was started in 1940 in order to better compete with the 601, following in its footsteps with a pressurized cooling system. The resulting 211E proved to be able to run at much higher power settings without overheating, so it was quickly followed by the 211F which included a strengthened crankshaft and a more efficient supercharger.

'Ideal' in a sense that it can offer competitive performance and maneuverability, along with excellent visibility, range, rate of roll and firepower.
MG FF was with low MV, the MG FFM was with decent MV at almost 700 m/s. The MG 131 was barely better at 710-750 m/s, depending on the ammo.
I'm not sure that anyone reckoned the MG FF(M) as overkill in any time. MG 81Z with explosive ammo will not get us anywhere.
The MG131 was firing faster bullets and much lower weight. But that was far less than the 7.92 bullet being fired at 850m/s.
The Luftwaffe used explosive 7.92 ammo historically:
  • B - Beobachtung ("observation") — The German Luftwaffe 10.85 grams (167.4 gr) B (Beobachtung—"observation") high-explosive incendiary ball bullets contained phosphorus and "had a pellet in it which exploded on contact with any target, however frail".[20] The projectile featured an internal floating firing pin mechanism that automatically armed during firing and detonates a small capsule of tetryl which in turn ignites the white phosphorus in the nose of the projectile during sudden deceleration producing a clearly observable amount of flash and smoke. It had a muzzle velocity of 800 m/s (2,625 ft/s) and an operating pressure of 300 MPa (43,511 psi). The B bullet was like any other high-explosive or incendiary bullet, illegal for anti-personnel use according to the Hague Conventions. "The Germans maintained that it was used mainly for observation and range-finding, but observers report having seen them in rifle clips and machine gun belts".[20] The regular German infantry units were not allowed to use this round; however German snipers on the Eastern Front were permitted by Adolf Hitler in February 1945 to use these rounds that caused horrendous wounds as the projectiles tended to detonate after 100 to 130 millimetres (3.9 to 5.1 in) penetration in human tissue. Karabiner 98k service rifles handled these cartridges without issues.[34] This cartridge can be recognised by the black primer sealant, yellow bullet. This ammunition was also produced in a B-v high-velocity or "v" ammunition variant that added 110 m/s (361 ft/s) muzzle velocity to the normal B variant.[33]
All verbesserte (v) ("improved") high-velocity ammunition variants were loaded to a 50 MPa (7,252 psi) higher operating pressure than the corresponding normal ammunition variants. This increase in operating pressure resulted in a noticeable increase in muzzle velocity and barrel wear.[33]

 
The problem with the Jumo 211 in 1940 was lack of ability to do 'sprints' like the BD601/5 and lack of pressurized cooling, which impaired it's performance at higher altitudes. That's not a problem for bombers as much in the period, but is a huge problem for fighters.
https://en.wikipedia.org/wiki/Junkers_Jumo_211

High-pressure cooling system (no aircraft engine used cooling systems that were open-ended) can allow for smaller coolers. Altitude performance of the Jumo 211B/D was on par with DB 601A - at 5 km the 211 was making 930 PS, the 601A with early S/C 900 PS, 601A wth later S/C 960 PS.
 

Deleted member 1487

High-pressure cooling system (no aircraft engine used cooling systems that were open-ended) can allow for smaller coolers.
This book from the wikipedia quote says otherwise:
  1. Christopher, John. The Race for Hitler's X-Planes (The Mill, Gloucestershire: History Press, 2013), p.78.
Altitude performance of the Jumo 211B/D was on par with DB 601A - at 5 km the 211 was making 930 PS, the 601A with early S/C 900 PS, 601A wth later S/C 960 PS.
Got a source backing that up? Also weren't the Germans using 601Aa and 601N as of 1940? Plus there is the supercharger issue and ability to sustain higher RPMs for extended periods.
 
This book from the wikipedia quote says otherwise:
  1. Christopher, John. The Race for Hitler's X-Planes (The Mill, Gloucestershire: History Press, 2013), p.78.
What does it say?

Got a source backing that up? Also weren't the Germans using 601Aa and 601N as of 1940? Plus there is the supercharger issue and ability to sustain higher RPMs for extended periods.

I may know where a power chart/table or two are located ;)
For example, the pg.19 of the manual for the Jumo 211 B and D contains table where power values at certain rpm and boost are listed: link
DB 601A power chart with initial S/C: link
DB 601A, with improved S/C: link
DB 601Aa was a version of the improved 601A with a bit improved low-alt performance, sacrificing a bit hi-alt perf.
601N was used sparsely in 1940.

Supercharger was nothing great on the 211s before the 211F, however the power delivered to the prop is what counts. 2400 rpm for 30 min on such a big engine is no small feat.
 

Deleted member 1487

What does it say?
The resulting Jumo 211 was first prototyped at Jumo's Dessau plant in 1935 and started testing in April 1936. Like the 210H, it featured a mechanical direct fuel injection system using small pistons driven off the crankshaft, three valves per cylinder, and an inverted V layout. It also had an open-cycle cooling system, not pressurized, as was the case on the later 213.[2]
Same thing I quoted from wikipedia before.

I may know where a power chart/table or two are located ;)
For example, the pg.19 of the manual for the Jumo 211 B and D contains table where power values at certain rpm and boost are listed: link
DB 601A power chart with initial S/C: link
DB 601A, with improved S/C: link
DB 601Aa was a version of the improved 601A with a bit improved low-alt performance, sacrificing a bit hi-alt perf.
601N was used sparsely in 1940.

Supercharger was nothing great on the 211s before the 211F, however the power delivered to the prop is what counts. 2400 rpm for 30 min on such a big engine is no small feat.
The big different is the Kampfleistung for the Jumo 211D was 5 minutes. The max Dauerleistung for the DB601A lasted for 30 min (900hp) and was substantially higher than the max Dauerleistung of the Jumo 211 (790hp). That's just the 601A not the 601Aa.

The 601N had several hundred examples in use during the BoB and was certainly in use in 1940, while the Jumo 211E/F wasn't in use until 1941. It's just hard seeing the Jumo 211D for a fighter engine having much success in 1941. You'd really need a DB601 to get the needed fighter performance.
 
The resulting Jumo 211 was first prototyped at Jumo's Dessau plant in 1935 and started testing in April 1936. Like the 210H, it featured a mechanical direct fuel injection system using small pistons driven off the crankshaft, three valves per cylinder, and an inverted V layout. It also had an open-cycle cooling system, not pressurized, as was the case on the later 213.[2]
Same thing I quoted from wikipedia before.

Reading the 'Flugmotoren und Strahltriebwerke' by Von Gersdorff et, pg. 86 being part of describing the Jumo 211s, refutes the claim that Jumo 211 ever used open-cycle cooling system (my bold):
Die Bauereihen A bis H hatten eine geschlossene Druckkuehlanlage,
Or, roughly:
Series from A to H have had closed pressure cooling system,

Wherein with the F it was introduced over-pressure cooling system (Ueberdruckkuehlanlage), that allowed for max temperatures of 115°C at sea level (later 120), vs. 95°C for the earlier series, thus allowing for greater power all-around. The change also allowed for smaller coolers. (all per same source)

The big different is the Kampfleistung for the Jumo 211D was 5 minutes. The max Dauerleistung for the DB601A lasted for 30 min (900hp) and was substantially higher than the max Dauerleistung of the Jumo 211 (790hp). That's just the 601A not the 601Aa.

The 601N had several hundred examples in use during the BoB and was certainly in use in 1940, while the Jumo 211E/F wasn't in use until 1941. It's just hard seeing the Jumo 211D for a fighter engine having much success in 1941. You'd really need a DB601 to get the needed fighter performance.

The table from the Jumo 211B - D plainly states that Kampfleistung is allowed for 30 min. The Max Dauerleistung was also 860 and 800 PS, not just 760. But we can also use the 2400 rpm setting in high gear, for 1100 PS at 4000 m: link.
'My' ALT Fw 190 with Jumo 211 D can be in service from 1st Jan 1940, not the case for anything with 601N onboard.
 

Deleted member 1487

Reading the 'Flugmotoren und Strahltriebwerke' by Von Gersdorff et, pg. 86 being part of describing the Jumo 211s, refutes the claim that Jumo 211 ever used open-cycle cooling system (my bold):
Die Bauereihen A bis H hatten eine geschlossene Druckkuehlanlage,
Or, roughly:
Series from A to H have had closed pressure cooling system,

Wherein with the F it was introduced over-pressure cooling system (Ueberdruckkuehlanlage), that allowed for max temperatures of 115°C at sea level (later 120), vs. 95°C for the earlier series, thus allowing for greater power all-around. The change also allowed for smaller coolers. (all per same source)
Thank you for the information and source, that does clear up the confusion from the wikipedia source.

The table from the Jumo 211B - D plainly states that Kampfleistung is allowed for 30 min. The Max Dauerleistung was also 860 and 800 PS, not just 760. But we can also use the 2400 rpm setting in high gear, for 1100 PS at 4000 m: link.
'My' ALT Fw 190 with Jumo 211 D can be in service from 1st Jan 1940, not the case for anything with 601N onboard.
So why was the Jumo 211 never used for a fighter?
 
So why was the Jumo 211 never used for a fighter?

Who knows? My guess is that Germany needed to make choices. So they went with DB 601/605 on fighters, Jumo 211 for bombers, some of them obviously needing twice as much as the fighters. For example, from Wikipedia entry about the Ju-88:

Dr. Heinrich Koppenberg (managing director of Jumo) assured Göring in the autumn of 1938 that 300 Ju 88s per month was definitely possible. Göring was in favour of the A-1 variant for mass production.

That would mean that Jumo needs to produce 7200 engines + parts per year just for that programme. Plus the later 601s, like the E and 605s were better at altitude (while Jumo went between the rock and hard place with the 222). We also have the BMW 139 and 801 in design phase, that no major aircraft was slated to use apart the Do 217, so the Focke Wulf got it for the 190.
The Ta-154 was to use the Jumos, ironically engine failures were to blame for half of prototype crashes.
 
So, where are we at? Have we reached consensus for any Nation yet?

What about USSR, Italy, and Japan?

On a public forum consensus is someties hard to reach :)
I take it that it would look like:
-Germany - Bf 109 with bigger/better wing and cooling system; He 100 with same; my pick will be Fw 190 with V12 engines and small wing. Daimlerized Fw 187.
-UK - Spitfire III with either mixed or all-cannon armament. Merlin Whirly.
-USA - (X)P-38, (X)F4U-1.
I'd also add the push-pull fighters, all of the coutries used pusher V12 engines in 1930s so it's not much of a stretch.

No much talk re. other countries. By your's truly, plus Archibald:
-Japan - Ki-27-lokalike with retractable U/C and 6 LMGs. Twin with 12 LMGs and as good radial as it gets.
-USSR - 2 cannons, engine AM 34, though the M103 looks decent for 1940 (they almost got the I-17 in production OTL). Proposing the M103- or AM-34-powered 'classic' twin with 4 cannons.
-Italy - the 'MC.201', sporting the Asso engine and 4 HMGs; I'll also propose the ALT Ro.58 with Asso and 6 HMGs.
-France - improved D.520/555, VG-33. Proposal for HS 12Y-powered twin with 4 cannons.
 

Driftless

Donor
Since this is AH, last minute entry from Poland: the PZL.50 Jastrub (designed in 1936, prototyped in 1939) It should have been fairly comparable to other radial-engine fighters from the mid-thirties, like the Seversky P-35, Curtis P-36, Macchi C.200, etc
 
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