Hungary steps into the breach.

I agree the condensers are not invulnerable but since they are 'leaky' holing them does not create an immediate issue as with a pressurized coolant system. However there are a few key points in the system that if hit puts the engine out quickly (main reservoir, piping, and electrical system) A few failed pumps (some sources say 22 inline) are not a major issue as they are centrifugal and flow can still continue albeit at a reduced rate.

There is a reference in Air Enthusiast that states that the two wing root guns could be replace by MG151s but I have not uncovered this in any source docs (If my mount i would choose three MG151/15)

I also tried to run to ground a report that a few He100s went to Norway when the Fw187s went there on service trials. The author of that tried to assert that would account for the Hurricane pilots reporting He113s in the area.
My efforts did not produce any evidence.

MÁVAG Héja
MÁVAG Héja - Wikipedia, the free encyclopedia
Two fixed forward-firing 12.7 mm (0.50 inch) Gebauer motor-driven machine guns in the fuselage nose

Why wouldn't a Hungarian produced He-100 be armed in a similiar manner?

krieghund said:

I agree the condensers are not invulnerable but since they are 'leaky' holing them does not create an immediate issue as with a pressurized coolant system. However there are a few key points in the system that if hit puts the engine out quickly (main reservoir, piping, and electrical system) A few failed pumps (some sources say 22 inline) are not a major issue as they are centrifugal and flow can still continue albeit at a reduced rate.

There is a reference in Air Enthusiast that states that the two wing root guns could be replace by MG151s but I have not uncovered this in any source docs (If my mount i would choose three MG151/15)

I also tried to run to ground a report that a few He100s went to Norway when the Fw187s went there on service trials. The author of that tried to assert that would account for the Hurricane pilots reporting He113s in the area.
My efforts did not produce any evidence.

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You have a lot more information than I thought was available. I have seen reference to a 4 gun wing but I don't know if the wing was stretched a bit or something taken out or if they just got better at cramming stuff in

Most of the advocates of the He 100 want to take the performance of the prototypes and use that as the performance of production combat examples or claim that additions can be made with little problem since other aircraft had additions made to them.
few other fighter designs of the time were as tight as the He 100 in regards to space/volume but that is one of the reasons for it's performance. TANSTAAFL.

There are a lot of 'reports' of meeting He 113s

davebender said:

MÁVAG Héja
MÁVAG Héja - Wikipedia, the free encyclopedia
Two fixed forward-firing 12.7 mm (0.50 inch) Gebauer motor-driven machine guns in the fuselage nose

Why wouldn't a Hungarian produced He-100 be armed in a similiar manner?

Click to expand...

What part of " the upper cowling was part of the engine mount" aren't you understanding?

The upper cowling including the surface skin was the structural support of the engine, the He 100 did not use a conventional engine mount. This is the reason it could not be switched to the Jumo 211 engine. Perhaps the cowl/engine mount could be modified to take guns, but it might require more engineering work than they thought was worthwhile.

Shortround6 said:

What part of " the upper cowling was part of the engine mount" aren't you understanding?

The upper cowling including the surface skin was the structural support of the engine, the He 100 did not use a conventional engine mount. This is the reason it could not be switched to the Jumo 211 engine. Perhaps the cowl/engine mount could be modified to take guns, but it might require more engineering work than they thought was worthwhile.

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This is why I believe the He100 was the inspiration for the plan-form Ki-61.

Two more weapons could have been added similar to the side fuselage weapons of the MC205N (early) but then that is more weight and drag.

The number of weapons may not be that crucial as many Russian fighters had only two or three, albeit 12.7 or 20mm.

1918 version of Gebauer MG was chambered for 7.92mm cartridge. During 1930s they made a .50cal version for use on Italian aircraft.

The DB601 engine is made for a prop cannon. I wonder if Hungary would take the Gebauer to the next level with a 20mm version. If they can achieve at least 1,000 rounds per minute you would only need the single hub cannon.

The He 100 might have been a more attractive fighter if the MG FF had proved more reliable in engine mounts earlier, if the MG 131 had matured earlier or if the MG 151 had matured earlier. Two Russian 7.62mm mg synchronized have a rate of fire just under two synchronized and one free firing Mg17s.

The Russian 12.7 gun had a rate of fire as good as the MG 131 while firing a much more powerful round. The Russian 20mm fires about 60% faster than the MG FF.

I could see a He 100 with an engine mounted Mg 151/20 and a MG 131 in each wing root but such a machine probably wouldn't show up any sooner than the 109 G with the same guns. And that is part of my criticism of the He 100 in many "what if' scenarios.

Without changing the armament time line ( gun availability) the He 100 is too lightly armed to be as effective as the 109 in the beginning of the war.

Changing the fuel tanks to self sealing is going to be difficult ( weight and capacity) and the cooling system offers an awful lot of area for hits. One rifle caliber hit is probably much less critical than a a similar hit in a conventional radiator but since the cooling system occupies many times the volume of a conventional radiator the chances of multiple hits goes way up. I don't know how many hits in the wing/stabilizer surfaces it takes to equal one hit a conventional radiator.

davebender said:

1918 version of Gebauer MG was chambered for 7.92mm cartridge. During 1930s they made a .50cal version for use on Italian aircraft.

The DB601 engine is made for a prop cannon. I wonder if Hungary would take the Gebauer to the next level with a 20mm version. If they can achieve at least 1,000 rounds per minute you would only need the single hub cannon.

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Only if your gun and engine designer is Dr. Who. The Gebauer MGs were twin barreled weapons. The DB series of engines had a tube through the engine that allowed for maximum of 70mm diameter. Trying to arrange the receivers of two guns close enough together that the outside dimensions of their barrels will be under 70mm is going to be near impossible.

This 70mm tube also limits export appeal any country that has adopted the Hispano gun ( or is favoring it). The Hispano gun has a gas port and gas cylinder under the barrel part way out. while the end of the barrel might fit in a DB engine the gas cylinder will require mounting the gun too far back with the back of the receiver sticking too far into the cockpit.

Another thought towards the armament is the different ballistics in the BF109E in which the Zero has the same problem. In a dogfight as you will encounter this problem as you are turning since the MG17 has a flatter trajectory than the MG-FF you may only be hitting your target with the two MG17. Saburo stated in his books that many of his victories were made with his twin 7.7 MG.

The MG151/15 is available in mid 1940 maybe a tad earlier in the year.

The velocity of the MG151/15 at 600m is the same at the muzzle of the MG-FF and has a very flat trajectory.

The MG 151/15 doesn't show up in the 109 until the F-2 model. First deliveries in Jan 1941. Manufacture started earlier and testing/clearance had to done before that. The gun was tested in Spain in 1938 in the nose of a twin engine aircraft and it may have been mounted in the nose of twin engine aircraft in the summer of 1940 but I would hold to the introduction of the F-2 as the earliest it will show up in a single engine fighter. The F-1 with the MG FF may have been a stand in until the MG 151 was cleared for use in the engine mount.
The other problem with the MG FF and the guns in the Zero were the 55-60 round drums. the guns ran out of ammo in just under 8 seconds. Leaving the fighters with over 20 seconds ( Zero) or 50 seconds ( 109E-3) firing time on the cowl machine guns.

If arming the He-100 is really this difficult then Hungary would probably opt to produce the He-112B which could carry 20mm FF cannon in the wings. However I find it difficult to believe Heinkel would design a late 1930s fighter aircraft that couldn't carry 20mm cannon.

Maybe the other countries who bought the few He-100's couldn't believe that it counldn't be uparmed too. But after looking close realized that and chose not to buy more or produce them.

Maybe the other countries who bought the few He-100's couldn't believe that it counldn't be uparmed too. But after looking close realized that and chose not to buy more or produce them.

Click to expand...

Historically neither the Fw-187 nor the He-100 could be produced during 1939 to 1941 due to a shortage of DB601 engines.

It was difficult to re-engine and up-arm, two big knocks against it.
A nice, pretty little fighter, with no developement potential.

The M151 was available in 1940 and was lent to Heinkel but I don't have that document at hand as to the date. However here is the cover page of the MG151 manual for a turret mount, probably for the BV138 dated Oct 1940.

When comparing the He100 you must do it to its peers and not thru the glasses of history. Of course it can't compete against the P-51 et al but from 1939 to 1941 it put them all to shame and I bet with an order the problems would have been solved as they were not insurmountable.

There was a larger wing of 10.8m span planned and engine upgrades thru the DB601E.

davebender said:

If arming the He-100 is really this difficult then Hungary would probably opt to produce the He-112B which could carry 20mm FF cannon in the wings. However I find it difficult to believe Heinkel would design a late 1930s fighter aircraft that couldn't carry 20mm cannon.

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It was "PLANNED" to carry a 20mm just as the 109 was "PLANNED" to carry a 20mm through the prop hub. It was just a lot more difficult to get the the 20mm cannon through the Prop to work than they thought at first. Or second....... or third. The Germans started with a large, heavy, slow firing cannon using the same round as the Flak 30 AA gun. The He 112v5 tested this gun in Spain. By the time they got it flying they realized the weight and rate of fire were not was wanted in an air to air weapon. I don't know when work started on the MG 151 but it seems the MG FF was always viewed as an interim weapon. It was installed (or planned for installation) in the engine of the 109C-2 but never produced in any numbers. There is a lot of controversy over engine mounted guns in the 109 series but it boils down to few, if any, ever seeing service despite what was wanted. The Jumo 210 could take ( had the tube for) an engine mounted gun, some Jumo 211s did (depending on gear ratio) and the DB series had the tube. Having the tube and actually getting the gun to function for more than a few shots were different things however. And this is part of what scuttles the He 100 as a practical fighter in 1939-40. Despite what was wanted or specified th eengine mounted guns were not working that well at the time.
The French Hispano engines ( and the Russian offspring) had both the intake and exhaust manifolds on the outside of the V leaving quite of bit of open space in the V. The German system actually only had the barrel in the engine, the rest of the gun was behind but the engine may have blocked airflow or provided ( against the desires of the gun guys) too much warm air to the gun for adequate cooling.

Heinkel may have been let down by the gun makers inability to deliver the gun/s promised in a timely manner.

krieghund said:

The M151 was available in 1940 and was lent to Heinkel but I don't have that document at hand as to the date. However here is the cover page of the MG151 manual for a turret mount, probably for the BV138 dated Oct 1940.

When comparing the He100 you must do it to its peers and not thru the glasses of history. Of course it can't compete against the P-51 et al but from 1939 to 1941 it put them all to shame and I bet with an order the problems would have been solved as they were not insurmountable.

There was a larger wing of 10.8m span planned and engine upgrades thru the DB601E.

Click to expand...

I don't believe I have ever compared it to "P-51 et al". but tried to compare it to it's peers. It did have excellent speed performance, BUT how did it get that performance? By using just about the smallest airframe of it's peers, and by using an unconventional cooling system. It carried less fuel ( somewhat offset by it's lower drag) in the initial versions (350 liters-77imp gallons) and even the planned armament (with the 20mm MG FF) was on the light side compared to it's peers. Most performance figures seem to be for versions with little (if any?) armor or with self sealing tanks. Granted in 1939/early 1940 few of it's peers had such protection either.

Many of these things could have been "fixed" or modified in 1940-41 just as they were for many of it's peers. The trouble is that as these problems are fixed the performance is going to fall, just as it did for many of it's peers. There is no doubt in my mind that a He 100 brought up to the full combat standards of the day would still have a considerable performance advantage over a 109E, (even though it carried 1/2 the cannon armament and 1/2 the 7.9mm machine gun ammo), the question is if it would have a significant performance advantage over the 109F and what are you giving up to get it, like ability to carry drop tank/s or bombs?

As the He 100 "evolved" it seemed to grow supplemental coolers. It grew a fuselage fuel tank to bring capacity up to 420 liters? Granted this may have allowed the often quoted 1000-1000km range. The tail surfaces grew and so on.

A manual published in Oct of 1940 for the MG 151 is consistent with the time line for the MG 151 as I laid it out. The 109F-2 with the MG 151 was not delivered to units until Jan 1941. manufacture of those aircraft had to have started in the end of Nov or start of Dec 1940. Weapons are not going to be installed in service aircraft and issued to units at this point in the war without training manuals and parts backup. (what happened in 1944/45 may be totally different). The MG 151 had been being worked on for a number of years at this point. The fact that the gun may have been approved for use in one application does not mean it was satisfactory in all applications and in any case the manual is only 1-2 months ahead of the gun going into the fighters. Considering the problems they had with the MG FF working in the 109 with the engine mounting despite giving good service in the 110 and in free mounts in other aircraft the fact that the MG 151 was in use in other aircraft doesn't prove it was combat ready in an engine mount for a fighter.

Perhaps you have the performance numbers for the D-1 version and information about the armor and fuel tanks (protected or not?)

I see some fundamental problems with the whole concept of Hungary investing or allowing Germany to invest in her aero industry.

Hungary was prohibited under the treaty of Triannon from having an army stronger than 35000 men, and any airforce. Slowly this restriction was relaxed, though never for German aircraft. After 1920 she was an economic basket case completely dependant on Allied money just to remain a solvent state. worse, the state was rampantly corrupt and socially fractured, with poor access to world markets. so very little of this money could be spent on industry, let alone politically dangerous military industries. Even less likely was possibility of Hungary closely aligning itself prewar with Germany. Sure there were elements of the far right that wanted this, and Horthy's natural inclination was to gravitate toward Germany, but economic and political realities prevented such a move from happening. Germany and Hungary remained more or less politically isolated from each other until after the fall of France

Any move toward rearmament using German manufacturing licences or investment would have left Hungary in the cold as far as foreign aid and investment was concerned, and upset most of her neighbours. She risked the very real prospect of invasion and/or blockade by any one of her much stronger and primal neighbours (especially the members of the so-called "little entente) if she upset them too much......

Moreover, whilst the 109 (and He100/112) were (or potentially could have been) outstanding military successes, as prewar military exports they were less favoured to potential purchasers to the manouver aircraft like the CR 32. Fiat knew the world market much better, and offered products that, whilst we now know were inferior capability wise, were much more saleable in the world market. Hungary was much more closely aligned to italy prewar than she was to Germany, which was acceptabloe to the allies, since italy was not seen as quite as dangerous as the nazis. this explains why Hungary went to war with mostly Italian aircraft, or aircraft of italian origin....the Heja, CR32, CR42 and CA 135 as well as a large number of Italian trainers. There were a few German aircraft all of which were received after 1938, and most of those received were reconnaisance or liason types like the He170 and the He 46. There was one exception, 60 Ju86Ks were more or less given to the Hungarians after Munich. After the outbreak of war the Hungarians received 12 Ju87s and a few over age He111s. In main fighting types, there was a near total lack of success enjoyed by German constructors in selling their product.....

Heinkel He 112 - Wikipedia, the free encyclopedia
7 Sep 1938.
Hungarian Air Force selects He-112B as their new fighter aircraft. Initial order for 36 aircraft.

RLM refused to allow Hungary to purchase 20mm MG FF cannon. Hungary made plans to use the locally designed 20mm Danuvia cannon instead.

5 Feb 1939.
He-112B V9 prototype arrives in Hungary for demonstration purposes.

10 March 1939.
A second He-112B prototype arrives in Hungary.

Apparently there was some debate whether Hungary should build the He-100 or He-112B.

May 1939.
Manfred-Weiss receives license to build He-112B locally.

Hungary replaced MG17 machineguns with locally built 39.M machineguns.

At this point, the engine issue came to a head. It was clear that no production line aircraft would ever reach Hungary, and now that the war was underway, the RLM was refusing to allow their export anyway. Shipments of the Jumo 211 or DB 601 were not even able to fulfill German needs, so export of the engine for locally built airframes was likewise out of the question.

By September, the ongoing negotiations with the RLM for the license to build the engines locally stalled, and as a result, the MKHL ordered Manfred-Weiss to stop tooling up for the production line aircraft. The license was eventually canceled in December.

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Kawasaki (Japan) acquired a license to build DB601 engines during 1937 so I think it's realistic for RLM to grant a similiar license to Manfred-Weiss. Perhaps they just need to provide Milch with a larger bribe, err gift. Local production of the DB601 would allow historical plans for Hungarian production of Heinkel fighter aircraft to proceed. They will be armed with 20mm Danuvia cannon (Whatever that is. Never heard of it.)

davebender said:

Kawasaki (Japan) acquired a license to build DB601 engines during 1937 so I think it's realistic for RLM to grant a similiar license to Manfred-Weiss. Perhaps they just need to provide Milch with a larger bribe, err gift.

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From Wiki, not the best source, welcome correction WITH source.

"Daimler-Benz granted Aichi Kokuki KK, a part of the Aichi Clock and Electric Co. (Aichi Tokei Denki KK), a license to manufacture the DB 600A through D models in November, 1936."

"By early 1938 the Japanese Navy had also acquired the German He 118 V4 two-seat dive bomber aircraft, along with its production rights. "

"By 1939, eleven of the more advanced model DB 601A engines were imported. Manufacturing rights were updated for Aichi and granted to Kawasaki to build this model. The new engine received AE1P as its experimental designation."

I seriously doubt that DB was granting (or the German military was allowing) the licencing of the most advanced version of the DB engine before it even entered full production in Germany.