Me-110 Underrated

Like I said, I know it wouldn't have been easy. But the Beau seems like a good place to start, and it was around through the whole war so there was some time to work on it and get it right. Ultimately they didn't have a need for it due to the Mustang or (the fully viable version of) the P-38. But it took a while before those were available.

Some points, by my personal point of view, must be remembered.

A - The evolution of the bomber was favoured by Air Staffs and so, by mid-30s' bombers had a speed similar, if not higher, of that of the contemporary biplane fighters (SM-79 – CR-32, to cite an Italian example), and the amount of strategical damage done by the bombers of that era was certainly enormously over estimated, as Guernica taught certainly false lessons.

B - When the idea of an high performance fighter arose, the engines of that period just permitted tiny aeroplanes with a limited range. The initial specification for MC-200 fighter (840 HP) initially required just one 0,50 MG and one hour of autonomy, increased to two later. Me 109 was designed, like the whole Luftwaffe, with tactical purpose of destroy every possible enemy interference, at a close distances from their bases, when tactical planes like Ju-87 and He-111, where "at work". That proved wonderfully with Poland, France and the first stage of the Russian campaign.

C - In the early-mid '30s, when all these planes ( Spitfire – Me 109 – Me 110) were conceived and designed, the French Army was considered, of course wrongly, as many of the ideas of the period, the strongest in the world, and nobody seriously believed that Wehrmacht could install their bases in the Calais area, almost at a walking distance from England (was not for the sea...)

D -To escort bombers to some particular (tactical) targets, but always on the front scenario, like a concentration of troups of an important airport or rail junction, a fighter with a sufficient range was needed, and that range could only be accomplished, in those times, only by a twin engine plane.

It is not, by my personal point of view, that Me 110 was wrong or underrated. When German soldiers put their feet to soak in the English Channel the war turned from tactical to strategic, a war that Wehrmacht, and much less Luftwaffe, was not at all prepared to fight.

Schweik said:

Basically of our six major aircraft producing powers: Russia, Germany, Italy, Britain, Japan and the US, The European powers focused more on interceptors or short range / frontal aviation types. It was the latter two which seemed to recognize the need for a long range fighter earliest which makes sense given geography. The Japanese initially focused on a long range escort fighter because of their experiences in China. The US foresaw a need to patrol long distances, envisioning the protection of their shorelines and places like the Panama canal.

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I agree that the Americans and Japanese focused on longer range fighters.
However the US never used it's initial long range fighters in combat. Or used very few of them. By the time the US actually got into the war the need for protection, at least in US eyes, trumped the need for range.
P-38 went from 400 gallons internal unprotected to 300 gallons protected. went back to 410 gallons on the P-38J
P-39 went from 200 gal on the prototype ( maybe?) to 170 gals in the YP-39 and P-39C but capacity fell to 120 gallons with the self sealing tanks.
P-40 went from 180 gal to 160gal in the P-40B to 148 gal in the P-40E as better protected tanks were fitted, later P-40s got slightly increased internal capacity although like the P-39, some models had rather restricted capacity in an effort to improve performance. (120 gals on some L's and N's)
Early F4F-3 and -3As had 160 gallons in unprotected tanks, this dropped to 147 gallons with the initial protected tanks and then to 144 gallons with the F4F-4. FM-2s had even less.
The older P-36 could hold 160-163 gallons but performance figures are usually for 105 gallons with the 58 gallon tank behind the pilot being an overload ferry tank.

However for context the US Army specification that lead to the B-26 bomber called for ".... a bombload of 3000 pounds was to be carried over a range of 2000 miles at a top speed of over 300 mph and at a service ceiling exceeding 20,000 feet." Now the B-26 as built didn't come close to that desired range but shows the difficulty any designer of a hypothetical escort fighter would have been up against. The US army was asking for 2000 mile range medium bombers and even longer range heavy bombers in 1939.

Schweik said:

The A6M was actually a stronger airframe than most people give it credit for. It was a carrier aircraft after all, and had a once-piece construction method rather than having the wings bolted on separately. It was very streamlined as well.

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It may have been stronger than many people give it credit for, and it may have stood up fairly well with good pilots. But that does not mean it was as strong as US or other western aircraft. There are two reasons for limiting dive speeds, 1 is the plane has control difficulties at high speeds. the 2nd is that parts start falling off the aircraft. They increased the dive speed of the Zero twice during it's career. If the early all metal Zero was limited to about the same dive speed as the fabric covered wing Hurricane what was the reason if it wasn't strength?

Schweik said:

Personally I think the design and engineering challenges could be met by most of the major nations, the bigger issue was the purchasing commissions, corporate bureaucracy, air force leaders and so forth having sufficient vision and prescience to know what they wanted and what was really going to be needed.

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In some cases you may be right however some nations were a tight spot with less than first class engines (France and Italy) and Britain had the double whammy of believing that monoplanes were a passing American fad and variable pitch propellers were the work of Satan.
or at least believing on fighters that the increase in performance of the change in pitch would be canceled out by the increased weight of pitch change mechanism.
If a country believed that a long range single seat, single engine fighter would be out performed (think out maneuvered rather than speed or climb) by the enemy short range interceptor with like power than perhaps building a long range twin engine fighter that could boom and zoom (although not using that phrase) instead of maneuver was a viable alternative.

Shortround6 said:

If the early all metal Zero was limited to about the same dive speed as the fabric covered wing Hurricane what was the reason if it wasn't strength?

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Control forces appear to be the main issue. Also one report stated "Both cylinder head and oil temperatures get too low for safe operation in prolonged dives."

Re: strength ... thread here - A6M3 safe loading factor

Shortround6 said:

I agree that the Americans and Japanese focused on longer range fighters.
However the US never used it's initial long range fighters in combat. Or used very few of them. By the time the US actually got into the war the need for protection, at least in US eyes, trumped the need for range.
P-38 went from 400 gallons internal unprotected to 300 gallons protected. went back to 410 gallons on the P-38J
P-39 went from 200 gal on the prototype ( maybe?) to 170 gals in the YP-39 and P-39C but capacity fell to 120 gallons with the self sealing tanks.
P-40 went from 180 gal to 160gal in the P-40B to 148 gal in the P-40E as better protected tanks were fitted, later P-40s got slightly increased internal capacity although like the P-39, some models had rather restricted capacity in an effort to improve performance. (120 gals on some L's and N's)
Early F4F-3 and -3As had 160 gallons in unprotected tanks, this dropped to 147 gallons with the initial protected tanks and then to 144 gallons with the F4F-4. FM-2s had even less.
The older P-36 could hold 160-163 gallons but performance figures are usually for 105 gallons with the 58 gallon tank behind the pilot being an overload ferry tank.

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All interesting, and fuel capacity is at least one way to try to estimate a baseline for range, but it's probably at least as limited as the USAAF method of levitating to a specific altitude and then measuring the resulting distance. Other factors you and I have mentioned or discussed before already include drag, engine RPM settings, engine critical altitude, and wing efficiency, and in addition to that there are also propeller type and settings and probably other "intangibles". In many cases, the effective range depended on how the aircraft was operated.

One of the best examples of this was with the P-38. Obviously with the high performance turbo-supercharged engine it could be quite the fuel hog. Even with the 400 gallon fuel capacity P-38s still needed to reach far across the Pacific to attack their targets (and to escort bombers). But they were struggling. Enter Charles Lindbergh. In July 1944, Lindbergh, who was something of an aviation genius albeit with some questionable political ideology, made a semi-legal visit to USAAF units in the Pacific, and began flying missions with the 475th Fighter squadron in New Guinea. At the time the P-38 had a flight endurance of 6-8 hours (depending how much high throttle was used) and a combat radius of 300 miles. Crew chiefs noticed that Lindbergh always had much more fuel than the other pilots when they returned. After some investigation and discussion Lindbergh's tweaks increased this to 8-10 hours and 500-600 miles. His method was simple in retrospect: reduce the standard 2,200 rpm to 1,600, set fuel mixtures to "auto-lean," and slightly increase manifold pressures. Conventional wisdom said this would cause detonation but it didn't. And this did not reduce cruise speed incidentally.

Similarly, mere fuel capacity apparently doesn't tell us the whole story with the various single-engined fighters. Though it only had 28 more gallons of fuel, the F4F-3 had a range of 860 miles and a combat radius of about 275 miles (without drop tanks), whereas the P-39D had a range of 390 miles (clean) and a radius of about 120 miles. Hence the constant complaints by US and Allied commanders about the viability of the aircraft. Drop tanks increased basic range to 600 - 700 miles (depending on who you believe), but the aircraft was still considered too short legged to be of much use as an escort or for example as a fighter bomber. I really don't know why the difference was so wide but I would guess that the Wildcat had a more efficient and certainly larger wing.

The P-40 fell somewhere in between with a range of 650 miles and a radius of 250 miles (or 200 miles for the P-40L). With drop tanks and an optimized flying regime they could make 850 miles range and roughly a 400 mile radius with a P-40e in the Pacific.

Of the three, only the P-38 came close to the combat radius of the A6M (up to 600 miles with the external tank), and only with the tweaks from Lindbergh. But both the Wildcat and the P-40 had considerably better range than most of the European or Russian fighters.

However for context the US Army specification that lead to the B-26 bomber called for ".... a bombload of 3000 pounds was to be carried over a range of 2000 miles at a top speed of over 300 mph and at a service ceiling exceeding 20,000 feet." Now the B-26 as built didn't come close to that desired range but shows the difficulty any designer of a hypothetical escort fighter would have been up against. The US army was asking for 2000 mile range medium bombers and even longer range heavy bombers in 1939.

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The Marauder was also required to carry a couple of tons of guns and ammunition. The more lightly armed Martin Maryland II (updated from French to British standards) had a range of about 1,200 -1,300 miles with armor and could make over 310 mph. And of course the early war B-17, originally designed to patrol the Coasts of the United States, also had quite a good range too. So it did make sense to have some long legged fighters.

It may have been stronger than many people give it credit for, and it may have stood up fairly well with good pilots. But that does not mean it was as strong as US or other western aircraft. There are two reasons for limiting dive speeds, 1 is the plane has control difficulties at high speeds. the 2nd is that parts start falling off the aircraft. They increased the dive speed of the Zero twice during it's career. If the early all metal Zero was limited to about the same dive speed as the fabric covered wing Hurricane what was the reason if it wasn't strength?

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Sometimes the issue with dive speed limiations is construction strength so to speak (arguably this was the case with some of the Russian fighters), sometimes it's more the shape and size. One thing the early Zero (A6M2) and Hurricane had in common was big wings. The A6M2 had a span of 39' 4". The Hurricane had a span of 40'. I think that had something to do with speed limitations, as the later marks of the zero had shorter wings, the A6M5 had a 36' span.

Not that wing span alone would account for speed limitations or problems at higher speeds but I don't think either the Zero or the Hurricane were designed with such high speeds in mind (so much faster than the engine could take them in level flight), or the problems which came with it, whereas later fighters were designed to deal with such problems. On the P-40 and some other aircraft, I think they just lucked out with wing designs which worked well at higher speeds. And high speed in a dive turned out to matter a lot for escape.

I'm not sure what the dive speed limitation was for the F4F.

In some cases you may be right however some nations were a tight spot with less than first class engines (France and Italy) and Britain had the double whammy of believing that monoplanes were a passing American fad and variable pitch propellers were the work of Satan.
or at least believing on fighters that the increase in performance of the change in pitch would be canceled out by the increased weight of pitch change mechanism.

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I could be wrong but I think France was well on their way to making some quite powerful variants of the old HS 12Y engine. No telling how they would have worked out of course. And needless to say, every nationality had their blind spots in terms of predicting what the machines of war would actually need.

If a country believed that a long range single seat, single engine fighter would be out performed (think out maneuvered rather than speed or climb) by the enemy short range interceptor with like power than perhaps building a long range twin engine fighter that could boom and zoom (although not using that phrase) instead of maneuver was a viable alternative.

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Without a doubt. The problem in that case basically came down to making a two seat fighter that took advantage of it's larger size to achieve greater range, which the Bf 110 basically didn't manage to do very well, and which was faster than the single seat types, which it was up to the Battle of France but fell behind on by the BoB, and never caught up.

I should add regarding the wings, that they had NACA data to go by in the US and this was also used I believe with some European aircraft.

Schweik said:

I should add regarding the wings, that they had NACA data to go by in the US and this was also used I believe with some European aircraft.

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By quite a few European aircraft, including most of Messerschmitt's.

This book has an article by an USAF major who gives an interesting baseline at a particular snapshot in time, November of 1943. By this time drop tanks were standard and cruise speed and other best practices had been worked out, improving range substantially. He lists the following combat radii:

P-39 - 310 miles
P-40 - 445 miles
P-38 - 575 miles
P-47 - 445 miles

There was a perceived need in the Pacific Theater to improve range for a "well armored fighter" to at least 600 miles. On some extreme fuel / endurance regime, P-38s were able to fly much longer missions up to 900 miles (such as by using huge 330 gallon drop tanks), but this was not routine.

After Lindbergh's assistance and new methods had spread, (he cites Sept 44 here) he says the P-38 range for routine missions was improved to 795 miles when doing fighter sweeps or medium bomber escort missions (carrying 425 gallons of fuel internally and 330 in external tanks) and 690 miles for heavy bombers (due to having to climb to higher altitude? Or due to lower cruise speed? I'm not sure) He also mentions they could fly a bombing mission carrying two 1,000 lb bombs and 425 gallons of internal fuel for a radius of 375 miles. For extreme range missions using 165 gallon and 330 gallon fuel tanks, they managed to reach as far as 1,400 miles.

By this point P-47's range had increased to the point that they had a radius of 690 miles carrying 370 gallons internal and 330 external. Apparently they sometimes flew missions with one external wing fuel tank and one bomb (!) which gave them a reach of 518 miles, or they could manage 320 miles with two 1,000 lb bombs.

This invites a very crude comparison. If you combine internal and external fuel for the basic / fighter sweep ranges,

P-38 755 gallons / 795 miles (1.05 miles per gallon)
P-47 700 gallons / 690 miles (1.01 miles per gallon)

... it looks like the P-38 was a bit more fuel efficient. That makes sense to me because in spite of having a greater wingspan and being a bit larger, I think the P-38 is more streamlined and probably less draggy. At any rate I think this implies that fighters consumed fuel at different rates, not that it should be a surprise.

There is a lot more data in there about fuel consumption and methods of fuel conservation (which were more complex than I earlier suggested) for P-38s.

Shortround6 said:

I agree that the Americans and Japanese focused on longer range fighters.
However the US never used it's initial long range fighters in combat. Or used very few of them. By the time the US actually got into the war the need for protection, at least in US eyes, trumped the need for range.
P-38 went from 400 gallons internal unprotected to 300 gallons protected. went back to 410 gallons on the P-38J
P-39 went from 200 gal on the prototype ( maybe?) to 170 gals in the YP-39 and P-39C but capacity fell to 120 gallons with the self sealing tanks.
P-40 went from 180 gal to 160gal in the P-40B to 148 gal in the P-40E as better protected tanks were fitted, later P-40s got slightly increased internal capacity although like the P-39, some models had rather restricted capacity in an effort to improve performance. (120 gals on some L's and N's)
Early F4F-3 and -3As had 160 gallons in unprotected tanks, this dropped to 147 gallons with the initial protected tanks and then to 144 gallons with the F4F-4. FM-2s had even less.
The older P-36 could hold 160-163 gallons but performance figures are usually for 105 gallons with the 58 gallon tank behind the pilot being an overload ferry tank.

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I didn't know the fuel loads were so substantially affected by self-sealing tanks, though they clearly provided a very useful role and allowed us to take a great deal of abuse compared to Japanese aircraft.

As an aside, I remember a system the USSR developed that involved pumping engine exhaust into the tanks to help inert them -- how did that work compared to self-sealing?

However for context the US Army specification that lead to the B-26 bomber called for ".... a bombload of 3000 pounds was to be carried over a range of 2000 miles at a top speed of over 300 mph and at a service ceiling exceeding 20,000 feet." Now the B-26 as built didn't come close to that desired range but shows the difficulty any designer of a hypothetical escort fighter would have been up against. The US army was asking for 2000 mile range medium bombers and even longer range heavy bombers in 1939.

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It seemed that the option for a twin-speed supercharger wouldn't have been available in the time-table, but it would have jacked the altitude up past 20000' without difficulty. I guess as a short-term goal, one could have fitted the plane with a single-stage twin-speed supercharger until a twin-speed arrangement was ready, but it would have required boldness.

Injecting CO2 into the tanks was a common method (but I think mostly used in bombers) to help prevent flashover and explosions. It was more of an addition to having self sealing tanks though not an alternative.

Zipper730 said:

I didn't know the fuel loads were so substantially affected by self-sealing tanks, though they clearly provided a very useful role and allowed us to take a great deal of abuse compared to Japanese aircraft.

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Self-sealing tanks were bulky due to the thick material used to seal the tank when punctured.
Different nations used various methods, but all variations added weight and reduced capacity.

Most ended up being basically a rather thick layer of rubber or something similar inside the tank which is why it reduces internal volume. Earlier attempts coated the outside of the tank but they didn't seem to work as well.

Schweik said:

Injecting CO2 into the tanks was a common method (but I think mostly used in bombers) to help prevent flashover and explosions. It was more of an addition to having self sealing tanks though not an alternative.

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The A6M injected exhaust gasses into the fuel tank.

Interesting, I wasn't aware. Didn't seem to help that much...

The self-sealing material was usually natural rubber, rubberized leather or rubberized cloth placed on the outside of the tank, not inside as the rubber swells when it gets in contact with the fuel, sealing the hole or greatly reducing fuel loss if the object hitting the tank was larger than rifle caliber.

Soviets also fed cooled exhaust gases into the fuel tanks in many of their combat a/c. Don't know how common self-sealing tanks were.

You have two different things going on.

The introduction of inert gas to the fuel tank lessens the risk of fire in a partially empty tank.
It does nothing to reduce the risk of fire from leaking fuel and does nothing to help preserve the fuel for the trip home or at least to friendly territory.

A lot of the high fuel capacities of the early American fighters are the result of integral tanks. Most of which, or all, could not be made self sealing and required actual tanks to be installed in the aircraft. These tanks could then have either external or internal protection.

My understanding is that most of the self-sealing fuel tank protection by the mid war was internal.

Schweik said:

Crew chiefs noticed that Lindbergh always had much more fuel than the other pilots when they returned. After some investigation and discussion Lindbergh's tweaks increased this to 8-10 hours and 500-600 miles. His method was simple in retrospect: reduce the standard 2,200 rpm to 1,600, set fuel mixtures to "auto-lean," and slightly increase manifold pressures. Conventional wisdom said this would cause detonation but it didn't. And this did not reduce cruise speed incidentally.

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Lindbergh gets a lot of credit, how much is deserved I don't know. Tony Levier was doing similar demonstrations in Europe in the summer of 1944 (?) and while Conventional wisdom might have said it would cause detonation that is NOT what Allison was saying at the time and it was NOT what Lockheed was saying at the time. But what did they know, they only built the engines and the aircraft and could not possibly be as smart as the Army Air Corp instructors.
BTW the British had figured out the low rpm-high boost thing back in 1941 or 42. Maybe other people had done it even sooner?
A Spitfire MK V could cruise at 10,000ft at 281mph true at either 2650rpm and +2lbs boost or 2000rpm and +3 3/4lbs boost, the first used 47imp gallons an hour and the 2nd use 42imp gal/hr. British published a number of altitude-speed rpm and boost numbers for various conditions.

Schweik said:

Similarly, mere fuel capacity apparently doesn't tell us the whole story with the various single-engined fighters. Though it only had 28 more gallons of fuel, the F4F-3 had a range of 860 miles and a combat radius of about 275 miles (without drop tanks), whereas the P-39D had a range of 390 miles (clean) and a radius of about 120 miles.

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Please make sure you are comparing like to like. especially combat radius at that has all kinds of conditions.
http://www.alternatewars.com/SAC/F4F-4_Wildcat_ACP_-_1_July_1943_(Tommy).pdf

range on internal fuel 860 statute miles at 161mph at 5,000ft.
combat radius on internal fuel 105 nautical miles.
Conditions for combat radius are given on page 2.

Point of bringing up the B-26 is to show what the planers were looking for, not what the actually got. The original B-26 requirement didn't have the top turret,it had a five man crew and four .30 cal guns. By the time the plane actually flew it had the twin .50s up top and a single .50 in the tail and could carry two 2000lb bombs, It was also much faster than the original requirement but much shorter ranged.
But note that the requirement that lead to the B-26 was put a couple of months before the P-40 (no letter) was even ordered. With the engines of early 1939 (or what is promised) what kind of fighter do you build for a 2000 mile mission? please remember that 100/130 fuel is almost science fiction. The US is just turning to 100/100 fuel (as later tested) from 91 octane fuel.

I don't necessarily see Lindbergh as an innovator here, so much as someone being sent to spread best practices. Needless to say somebody as wealthy, well-connected, and publicity seeking as Charles Lindbergh may well have embellished the story and some of his friends may have gone along with it. They certainly covered up some of the things he was up to. Patriotic exploits in the Pacific can help offset some of his highly questionable antics at the beginning of the war.

Pre-war they still thought that the bomber always gets through so they may not have been thinking so much of the need for escort fighters. That became increasingly apparent however to people who were paying attention as the war warmed up from the regional conflicts in Spain in Manchuria, Ethiopia, etc and moved into Poland, France, Greece. And Britain.

By then, it was clear there was a need.

But already in the very beginning of the war the Americans had some medium ranged fighters, and they did come in handy.

As for the specific combat radius of the Wildcat, my understanding is that combat radius increased through a combination of adding a bit more fuel sometimes with better engines, better flying practices / flying optimization. I believe I can find some sources to back up my numbers for the wildcat, I already provided one for the army fighters.