AHC: the best possible Luftwaffe for 1940

Some comments on issues already raised:

Unpressurized coolant boiling temperature decreases about 1.72 degrees F per thousand feet of altitude. A pure water cooled, but unpressurized system at 18,000 feet, would boil at an indicated 180F. Temperature lapse at altitude would increase the heat rejection to ambient from the the lower temperature coolant, but the engine would still see a 180F internal coolant temperature. Above that temperature coolant would vaporize within the engine and, as steam, be unable to extract enough heat to prevent boil-over and coolant loss.

Thank you. 18000 ft = around 5500 m.
Ju-88A-1, engine Jumo 211B, service ceiling after dropping the bombs was 9350m per manual, pg. 11 of the pdf.

I'm surprised by the comparison photos of the evolving Curtiss P-40. I would have bet that the first version with the relatively clean nose and belly radiator would have been the fastest. The gun fairings might have screwed up prop flow and could have benefited from some tuft testing. The radiator duct appeared like a short, simplistic fairing (tho in the right place) rather than anything incorporating Meredith's teachings.

If there is a report dealing with these mods, I'd love to see it.

The radiator on the 1st XP-40 was probably of same layout as it was on Hurricane or Typhoon's prototype - 'stick it into slipstream' type, with none of radiator's bulk being within fuselage?
 
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Deleted member 1487

2 x 10 kg is large weight increase? The wing bulges were used already on Fw-190A-1/A-2, that used 60rd drum, as well as on the Bf 109E-3 to E-7.
60 rd drum height and width was within a few mm vs. the 90 rd drum.
In the wings it is, especially if it is accompanied by a bulge in the wings to fit it like the FW190. Plus there was no 90 round drum Bf109 I've found.

No, not me. I'd have Ju-88 with, you guessed it, normal bomb bay. He 111 stays as-is - a capable bomt truck, that requires fighter escort to get the job done.
What does normal bomb bay even mean anymore at this point in the convo?

Not as much as for a twin engined A/C.
No, probably not. Though it is hard to tell given the delicacies of the me109s landing and taking off.

For maximum continuous in high S/C gear, the Jumo 211B was to be run at 2100 rpm and up to 0.90 ata under 4.5 km, and at 2300 rpm and up to 1.05 ata above 4.5 km. That is 200 rpm more, not less at higher altitudes.
Wasn't that more to do with the pressure of the atmosphere at lower altitudes?

Germans/DB shot themselves in foot when increasing compression ratio when going from DB 601A to 601N - from 6.9:1 to 8.2:1. For comparison, Merlin was at 6:1, V-1710 at 6.65:1. Greater compression ratio vastly incresses stress the engine must endure, for a small gain in power.
DB reduced CR for DB 601E to 7.2:1.
I'll have to take your word for it, that is an aspect of German engines I'm not familiar with.

Thank you. 18000 ft = around 5500 m.
Ju-88A-1, engine Jumo 211B, service ceiling after dropping the bombs was 9350m per manual, pg. 11 of the pdf.
The service ceiling is where the engine stops working:
https://en.wikipedia.org/wiki/Ceiling_(aeronautics)#Service_ceiling
Not necessarily where the cooling system stops working effectively, requiring a drop in hp.
 
In the wings it is, especially if it is accompanied by a bulge in the wings to fit it like the FW190. Plus there was no 90 round drum Bf109 I've found.

The Bf 109E3 to E-7 already featured bulges for cannon drums. I never said that 109s used 90 rd drum.

What does normal bomb bay even mean anymore at this point in the convo?

Hopefully, 1500 kg capacity. 3 x 500 kg is a nice, round number after multiplication.

Wasn't that more to do with the pressure of the atmosphere at lower altitudes?

I was expecting that you'd say, after all of this exchange, something along 'yes, no Jumo 211 engine ever used open-cycle cooling system'. But, alas.

The service ceiling is where the engine stops working:
https://en.wikipedia.org/wiki/Ceiling_(aeronautics)#Service_ceiling
Not necessarily where the cooling system stops working effectively, requiring a drop in hp.

From your source: " Service ceiling is where the rate of climb drops below a prescribed value. "
Service ceiling is lower than absolute ceiling, that is defined: " The absolute ceiling is the highest altitude at which an aircraft can sustain level flight. " per same source
 

Deleted member 1487

The Bf 109E3 to E-7 already featured bulges for cannon drums. I never said that 109s used 90 rd drum.
Hadn't noticed before, but yes. So I guess it could be done, but at a maneuverability cost. I know you didn't claim they did have them IOTL, just that you'd suggest it.
That'd be fine for bomber killing, but would probably require a fighter escort with lighter loading.

You never commented on my proposition of a lighter equipped Bf109E for fighter hunting and a bomber killer 'heavy' bf109, thoughts?

Hopefully, 1500 kg capacity. 3 x 500 kg is a nice, round number after multiplication.
It would require a fuselage/bomb bay longer than the Do217E, as they could take 'only' 4x 500kg bombs 2 side by side. Getting 3 in line would require a longer, but as deep of a bomb bay, which is much larger than the OTL Ju88. At best with a more open bomb bay you could get 4x 250kg bombs.

From your source: " Service ceiling is where the rate of climb drops below a prescribed value. "
Service ceiling is lower than absolute ceiling, that is defined: " The absolute ceiling is the highest altitude at which an aircraft can sustain level flight. " per same source
Basically unable to climb higher.
 
you can fiddle with the Luftwaffe aircraft as much as you like but IMVHO unless you completely change the modus operandi of the Nazi party and the senior command of the Luftwaffe the RAF will still win the BoB. Fundamentally change the methodology of the attack and the tactics used and then the Luftwaffe might wrest air superiority from Fighter Command for a short time. However as has been pointed out by other posters the British aircraft industry is out producing the German one regarding replacing losses and unless RAF pilot losses are increased significantly, it is the Luftwaffe who will run into serous problems first.
 
Hadn't noticed before, but yes. So I guess it could be done, but at a maneuverability cost. I know you didn't claim they did have them IOTL, just that you'd suggest it.
That'd be fine for bomber killing, but would probably require a fighter escort with lighter loading.

I don't think that Bf 109E even with extra 100 kg would've required fighter escort.

You never commented on my proposition of a lighter equipped Bf109E for fighter hunting and a bomber killer 'heavy' bf109, thoughts?

Having both light- and heavily-armed 109 will require at least two things - that LW has a considerable numerical advantage in fighters vs. France and UK in same time, and that LW can actually field exactly required sub-version of the 109s against the exact threat/target.

It would require a fuselage/bomb bay longer than the Do217E, as they could take 'only' 4x 500kg bombs 2 side by side. Getting 3 in line would require a longer, but as deep of a bomb bay, which is much larger than the OTL Ju88. At best with a more open bomb bay you could get 4x 250kg bombs.

I'd have two 500 kg bombs one by another in front part of bomb bay, and third behind them.

you can fiddle with the Luftwaffe aircraft as much as you like but IMVHO unless you completely change the modus operandi of the Nazi party and the senior command of the Luftwaffe the RAF will still win the BoB. Fundamentally change the methodology of the attack and the tactics used and then the Luftwaffe might wrest air superiority from Fighter Command for a short time. However as has been pointed out by other posters the British aircraft industry is out producing the German one regarding replacing losses and unless RAF pilot losses are increased significantly, it is the Luftwaffe who will run into serous problems first.

Indeed, Germany needs to produce much more fighters to efficiently battle the RAF in the BoB. As per the table posted earlier, they made perhaps 40% worth of British fighters production historically in BoB - hence my dislike for 2-engined LW fighters for 1939-40.
They will loose more aircraft due to georgaphic-related inability to recover moderately-damaged aircraft. Also much more pilots is needed, both to fill the incresed number of seats, and since they will be seldom rescuing a downed pilot, unlike the RAF that fights over the home turf.
 
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Deleted member 1487

Having both light- and heavily-armed 109 will require at least two things - that LW has a considerable numerical advantage in fighters vs. France and UK in same time, and that LW can actually field exactly required sub-version of the 109s against the exact threat/target.
Given that they historically fielded a ton of different sub-versions at the same time (just look at the E-G series) that shouldn't be too much of a stretch, especially given that we are positing that they'd have eliminated the twin engine fighters, so have a lot more single engine fighters to work with.

I'd have two 500 kg bombs one by another in front part of bomb bay, and third behind them.
Those are very fat bombs and I cannot think of a single German or any other nation's bombers that was laid out in such a way that they could have two side by side up in one segment and only 1 in the section behind it.

Indeed, Germany needs to produce much more fighters to efficiently battle the RAF in the BoB. As per the table posted earlier, they made perhaps 40% worth of British fighters production historically in BoB - hence my dislike for 2-engined LW fighters for 1939-40.
They will loose more aircraft due to georgaphic-related inability to recover moderately-damaged aircraft. Also much more pilots is needed, both to fill the incresed number of seats, and since they will be seldom rescuing a downed pilot, unlike the RAF that fights over the home turf.
For one thing they won't lose so many Bf110s in August in escort missions, which saves a ton of pilots and aircraft over OTL. Given that the Me109s were much more survivable against RAF SE fighters, especially the Hurricane, and may well do even better with a lighter 'fighter hunting' version of the Me109E the Luftwaffe would have a pretty serious advantage over OTL there. Perhaps the savings may be even greater if we suppose that a working wooden drop tank is available in the proposed scenario so fighters don't have to worry about turning back early and they have fewer losses than the Bf110 did IOTL in France due to being more surviveable against enemy fighters and having more fighters overall means less exhaustion for pilots flying lots of missions through May. As it was about 32% of the operational Bf110s were lost in the Western Campaign in May-June 1940.
 
Given that they historically fielded a ton of different sub-versions at the same time (just look at the E-G series) that shouldn't be too much of a stretch, especially given that we are positing that they'd have eliminated the twin engine fighters, so have a lot more single engine fighters to work with.

Going with a heavier armed fighters, you can have 100% or fighters that are both capable of killing either fighters or bombers. Going for, say, 70%+30% division (heavier- vs. lighter-armed), air controllers need to be very sure that lightly-armed types are actually engaging enemy fighters, not bombers. That might be hard to judge from a bunker 200 km away. Not just that, this is a reduction of 30% of fighter force that has an effective bomber-busting weponry.

The MG FF and MG FFM on Bf 109Es and 110s wrecked several several airforces historically, including fighters' component.

Those are very fat bombs and I cannot think of a single German or any other nation's bombers that was laid out in such a way that they could have two side by side up in one segment and only 1 in the section behind it.

The Do 217E-2 carried 2x1000 kg and 2x500 kg in the same time, despite it's less than ideal bomb bay. Even 3x1000kg, two of them side-a-side. Pg. 9 of manual.
Very fat bombs were 1400kg and 1800 kg.
But, in case that 2x500 cannot be seated one by another on 'Ju 88+', then I'd opt for two pairs of 500+250 kg.
 

Deleted member 1487

So another option in terms of fighter armament:
https://translate.google.com/transl....org/wiki/Scotti/Isotta_Fraschini&prev=search

Without the details on the weight and ROF Scotti made a lighter, faster firing 12.7mm HMG than the Breda-SAFAT one from 1933 on. It couldn't be synchronized, but if you have the motor cannon mount and one in each wing you'd have a hard hitting HMG against any fighters of WW2, especially with the German HEI-T round already developed for their 13mm HMG, but without the weight penalty of the Breda as well as a better rate of fire to really take advantage of the belt feed extra ammo and avoid the problems of low rates of fire in aerial combat. Plus apparently unlike the Breda it had an open bolt design which didn't overheat as quickly.

Going with a heavier armed fighters, you can have 100% or fighters that are both capable of killing either fighters or bombers. Going for, say, 70%+30% division (heavier- vs. lighter-armed), air controllers need to be very sure that lightly-armed types are actually engaging enemy fighters, not bombers. That might be hard to judge from a bunker 200 km away. Not just that, this is a reduction of 30% of fighter force that has an effective bomber-busting weponry.

The MG FF and MG FFM on Bf 109Es and 110s wrecked several several airforces historically, including fighters' component.
So what was the point of the entire argument about the Breda HMGs? The MG FFs were already superior by far in their killing ability due to their HE content and adding the 90 round drums, even with the weight penalty, only further makes them a better option if all you care about is individual round killing capacity. At that point you could even remove the regular MGs from the nose mount and use the Scotti HMGs in the motor cannon installation for added hitting power.

The Do 217E-2 carried 2x1000 kg and 2x500 kg in the same time, despite it's less than ideal bomb bay. Even 3x1000kg, two of them side-a-side. Pg. 9 of manual.
Very fat bombs were 1400kg and 1800 kg.
But, in case that 2x500 cannot be seated one by another on 'Ju 88+', then I'd opt for two pairs of 500+250 kg.
Ok? They had still had 4 attachment points for heavy bombs even if they could only fill 3 of them at a time to keep the loaded weight to a reasonable limit.

My point was you can't transition that hard from one very wide section to a narrow one that quickly in an aircraft. If you are going to have one that has a reasonable weight and aerodynamic profile you need to restrict the internal size of the bomb bay and fuselage diameter. If you go up to Do217 size for big bombs then you need Do217 sized engines to maintain performance.
 
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Deleted member 1487

Firing from an open bolt shouldn't change the rate of heating up. It only prevents cooking off a round in the chamber.
Supposedly it allows better air flow in the barrel and chamber. Part of the reason after all that there is a cook off concern is how quickly the weapon is heating up.
 

longsword14

Banned
Supposedly it allows better air flow in the barrel and chamber.
I think the heating up thing is a myth. After all, a close bolt gun must also go through the exact same steps so airflow would not be drastically reduced.
The cook off thing makes much more sense. The Maxim fired from a closed bolt but it also has water cooling.
 

SwampTiger

Banned
A quick perusal of Wiki shows the introduction of the Me 110 D-1 with 900 liter/238 gallon drop tanks and an 85 liter oil drop tank. These were available should the Luftwaffe decide to utilize them. The drop tanks for the Me 109 E were 300 liter/79 gallon tanks. Could the Me 109 E variants handle the heavier 900 liter tanks?
 

Deleted member 1487

I think the heating up thing is a myth. After all, a close bolt gun must also go through the exact same steps so airflow would not be drastically reduced.
The cook off thing makes much more sense. The Maxim fired from a closed bolt but it also has water cooling.
The difference is between bursts the chamber is open and clear, but in a closed bolt it would be closed and filled with a round.
 

Deleted member 1487

A quick perusal of Wiki shows the introduction of the Me 110 D-1 with 900 liter/238 gallon drop tanks and an 85 liter oil drop tank. These were available should the Luftwaffe decide to utilize them. The drop tanks for the Me 109 E were 300 liter/79 gallon tanks. Could the Me 109 E variants handle the heavier 900 liter tanks?
No it was only rated for the 300l tanks, which increased the range to 840 miles.
 

SwampTiger

Banned
I think the heating up thing is a myth. After all, a close bolt gun must also go through the exact same steps so airflow would not be drastically reduced.
The cook off thing makes much more sense. The Maxim fired from a closed bolt but it also has water cooling.

The heating of the barrel and chamber promotes cook-off, which is caused by an overly hot chamber lighting the powder charge. The hot barrel also warps, reducing accuracy and velocity.

Thanks, wiking, I was wondering if a greater range increase was possible. May take a larger aircraft.
 
So another option in terms of fighter armament:
https://translate.google.com/transl....org/wiki/Scotti/Isotta_Fraschini&prev=search

Without the details on the weight and ROF Scotti made a lighter, faster firing 12.7mm HMG than the Breda-SAFAT one from 1933 on. It couldn't be synchronized, but if you have the motor cannon mount and one in each wing you'd have a hard hitting HMG against any fighters of WW2, especially with the German HEI-T round already developed for their 13mm HMG, but without the weight penalty of the Breda as well as a better rate of fire to really take advantage of the belt feed extra ammo and avoid the problems of low rates of fire in aerial combat. Plus apparently unlike the Breda it had an open bolt design which didn't overheat as quickly.

Like every device, it has it's pros and cons. If indeed it was lighter (and smaller) - perhaps install 2 per wing for 4 guns total?
As always - API all the way for HMGs :)

So what was the point of the entire argument about the Breda HMGs? The MG FFs were already superior by far in their killing ability due to their HE content and adding the 90 round drums, even with the weight penalty, only further makes them a better option if all you care about is individual round killing capacity. At that point you could even remove the regular MGs from the nose mount and use the Scotti HMGs in the motor cannon installation for added hitting power.

I prefer a situation with greater firepower vs. a situation with lower firepower.
The HMG firing API adds armor-piercing feature to the firepower. so we might kill enemy pilot instead of have him slightly wounded by shell fragments. Also means retaining ability to fire at enemy once the 90 rd drum is emptied somewhere over Midlands.

Ok? They had still had 4 attachment points for heavy bombs even if they could only fill 3 of them at a time to keep the loaded weight to a reasonable limit.

My point was you can't transition that hard from one very wide section to a narrow one that quickly in an aircraft. If you are going to have one that has a reasonable weight and aerodynamic profile you need to restrict the internal size of the bomb bay and fuselage diameter. If you go up to Do217 size for big bombs then you need Do217 sized engines to maintain performance.

I will not narrow down the aft part of bomb bay. You can note that 250+500 kg bombs side-a-side are narrower than 500+1000 kg.
Same as Do-217, the Ju-88A-1 and A-5 was wide enough to carry 4 rows of 50 kg bombs. Manual, especially pg. 31.
Reduced to 2 rows with A-4 and it's offsprings.

A quick perusal of Wiki shows the introduction of the Me 110 D-1 with 900 liter/238 gallon drop tanks and an 85 liter oil drop tank. These were available should the Luftwaffe decide to utilize them. The drop tanks for the Me 109 E were 300 liter/79 gallon tanks. Could the Me 109 E variants handle the heavier 900 liter tanks?

Even if 900L can be carried, once the tank is dropped the user might found himself much further away from the friendly base than it has fuel for to return. For combat missions, fighters usually carried 50-100L extra of fuel in drop tanks for each 100L they held in internal tanks
 

Deleted member 1487

Thanks, wiking, I was wondering if a greater range increase was possible. May take a larger aircraft.
There was a limit of the lifting capacity of the aircraft (the Bf109E had probably with some bombs too) and there was also the question of the ground clearance ability of the landing gear with the tank. I think the 900l model was just too big and heavy.
 
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