He 112 vs. Hungarian recce aircrafts, Truth or legend...?

According to some data posted on the internet, during the “1940 Transylvanian crisis” between Romania and Hungary (pre-September Vienna Diktate), there were several unsuccessful attempts of the Romanian Heinkel He-112s of the 51st fighter squadron to intercept the Hungarian reconnaissance aircrafts which flown recon/photography missions over Transylvania. The failure was supposedly caused, according for example to Wikipedia (http://en.wikipedia.org/wiki/Heinkel_He_112 ), by He-112's modest speed. Moreover, lacking more able fighters in the area, the FARR Command relegated, for a short while, the Heinkel He-111 bomber for the role of interceptor (!) to the Hungarian reconnaissance missions. When, a while ago, I manifested my surprise that a relative modern fighter plane could have been slower than contemporary recce/bombers, Denes explained that the limitations were actually referring to the fighter’s maximum ceiling, compared to the planes it was destined to fight with (thanks again, Denes). But what continues to intrigue me is that, according to some sources, even this explanation seems to be questionable. Conforming to the mentioned sources not only that the He-112 was (nominally) faster then the recon-bombers available to Hungary during 1940 (Junkers Ju-86 and Heinkel He-70 K), but also its service ceiling was (probably) higher. On the other hand, He-112's both speed and ceiling were superior (or equal, in the case of ceiling) to those of He-111, so this raises the question “why would one think to use the later instead of the former for interception missions?”

Here are the technical data:

Heinkel He-112 B: max. speed: 510 km/h; service ceiling: 9.500 m - http://en.wikipedia.org/wiki/Heinkel_He_112 , 8.500 m - http://www.warbirdsresourcegroup.org/LRG/he112.html (8.500 for He 112 B1 and 9.500 for He-112 B2, according to www.worldwar2.ro )

Heinkel He-111 H3 (in use in FARR in 1940): max. speed: 406 km/h - www.wolrdwar2.ro , 415 km/h - http://www.warbirdsresourcegroup.org/LRG/he111h3.html ; service ceiling: 8.501 m – www.worldwar2.ro, 7.800 m - http://www.warbirdsresourcegroup.org/LRG/he111h3.html
[Heinkel He-111 H6: max. speed: 400 km/h - http://en.wikipedia.org/wiki/Heinkel_He_112 ; service ceiling: 8.390 m (http://en.wikipedia.org/wiki/Heinkel_He_112 ]

Junkers Ju-86 E1: max. speed: 325 km/h (R1 - 420 km/h); service ceiling: 6.800 m (R1 - 13.000 m) - http://www.warbirdsresourcegroup.org/LRG/ju86.html
[E - standard version with 800 or 880 hp BMW engines, G - modified version with round, glazed nose, K - export version with 905 hp Mercury engines, P and R - high altitude recon upgraded versions with 1.000 hp turbocharged Jumo engines]
Note: according to the same site, Hungary used 66 domestically build aircrafts (K-2 model). It did not buy/built the P/R high altitude version, so even if the speed/ceiling of the Hungarian Ju-86 could have exceeded the characteristics of the E1 model presented above, most probably they would not parallel those of the P/R models. In order to conclude that it is enough, I think, to compare the Mercury engine of the K models with the BMW used on the Es and with the Jumo used on P and Rs.

Heinkel He-70 F-2: max. speed: 360 km/h; service ceiling: n/a - http://en.wikipedia.org/wiki/Heinkel_He_70 , http://www.warbirdsresourcegroup.org/LRG/he70.html
Note: Hungary license-built the K fast-reconnaissance model (also known as He-170 A), having a more powerful 910 (1.000, according to some other sources) hp radial engine instead of the 750 hp “regular” one. So, there must have been a higher maximum speed for the He-70 K. But even so, I don’t think that its performances could have exceeded (by a visible margin) that of the He-111, which was considered its successor and which, in turn, was clearly inferior to He-112 in speed and inferior (or at best equal) with it in service ceiling. Not to mention aspects such as maneuverability and agility when comparing a dedicated interceptor with a two-engine medium-heavy bomber.

So, where lies the truth? Any sources or rational/reasonable explanations fot these two "myths"?

This post has been edited by Agarici on May 01, 2007 04:57 pm

Here are the detailed datasheet for both aircraft types in use with the MKHL in 1940, mentioned by Agarici in his post:

AIRCRAFT SPECIFICATION

DESCRIPTION: fast reconnaissance

SHORT HISTORY: He 70 ‘Blitz’ was designed as a fast mail and passenger airplane. Aerodynamically very clean, and with a retracting undercarriage, in April 1933 the first prototype (He 70a) attained top speed of 377 km/hour, faster than any of existing fighters at that time. He 70c began the first military version. In 1937 appeared He 170 (70K), in German documents also recorded as ‘He 70 Ungarn’, export version fitted with a radial engine, delivered to Hungary between September 1937 and February 1938. Retired from first-line MKHL service in 1942.

Type: long-range reconnaissance plane
Manufacturer: Ernest Heinkel Flugzeugwerke, Rostock-Marienehe
Manufacturer's Designation: He 170K (‘He 70 Ungarn’)
Years of Production: 1934-1937
MKHL Designation: He 70K távolfelderítö repülögép
Number in Inventory: 18
Air Ministry Type number: 24.01
Military markings: F.401 – F.418 [earlier HA-HTA – ‘HTS]

Wingspan: 14.80 m
Length: 11.70 m
Height: 3.10 m
Wing Area: 36.50 m2
Empty Weight: 2,300 kg
Take off Weight: 3,540 kg

Number of Engines: 1
Engine Type: WM-14A, 14-cylinder radial
Engine Output: 910 HP
Maximum Speed: 455 km/hour
Ceiling: 8,300 m
Climbing rate: 4530 m in 2.5 min.
Range: 900 km

Crew: 3
Armament: 1 x 8.00 mm Gebauer 34M GMK MG on flexible mount in rear cockpit

Note: for its time a very modern airplane of all-metal construction (structural parts made of light Duraluminium, while the metal skin of Aluminium and Magnesium alloy), retractable undercarriage and revolutionary clean aerodynamic lines, including elliptically shaped wings. The He 70 set up new standards in aerodynamic constructions.

* * *

AIRCRAFT SPECIFICATION

DESCRIPTION: medium bomber

SHORT HISTORY: the Ju 86 was designed from the beginning as both bomber and civilian transport. It flew first in 1934, and was used in various variants up to the late forties by the Swedish air force. Hungary obtained its remotorized aircraft in 1937-1938, and used them up to 1944, first as bombers, later in the war as reconnaissance and transport planes. Three were relegated to training role (relegated to transport role in 1940), while two were rebuilt for long-range reconnaissance duty in 1939, by adding an extra 3000-litre fuel tank, mounted in the bomb bay, and by fitting them with two photo cameras (type C5A and C10A), each. Their new ceiling was 7,400 m, while range was 1,460 km. Relegated to transport role in 1943. Two G-1s arrived in 1943, used as courier airplanes to the Eastern Front.

Type: medium bomber
Manufacturer: Junkers Flugzeug- und Motorenwerke AG, Dessau
Manufacturer's Designation: Ju 86K-2
Years of Production: 1935-1940
MKHL Designation: Ju 86K-2 nehézbombázó repülögép
Number in Inventory: 63+2
Air Ministry Type number: 53.01
Military markings: B.301 – B.363 (earlier HA-JBA, ‘JLA, and ‘JDA)
three trainers G.211 – G.213, two long-range reconnaissance airplanes G.214 – G.215, two courier airplanes (G-1) G.308 – G.309

Wingspan: 22.48 m
Length: 17.88 m
Height: 4.70 m
Wing Area: 82.00 m2
Empty Weight: 5,025 kg
Take off Weight: 8,000 kg
Number of Engines: 2
Engine Type: WM-Gnome&Rhône 14Kirs, 14-cylinder radial
Engine Output: 900 hp each
Maximum Speed: 385 km/h
Ceiling: 6,000 m [7,400 m for the recce version]
Climbing rate: 6,000 m in 6.9 min.
Range: 840 km
Crew: 4
Armament: 3 x flexible 8 mm GEM MG, 1,000 kg of bombs
(64 x 10 kg, or 16 x 50 kg, or 4 x 250 kg)

Note: the Ju 86 had a modern stressed aluminum skin all-metal construction. Originally designed for Diesel engines, the export models used engines specified by the customer. The Hungarians used licensed French radials, manufactured by Weiss Manfréd.

* * *

I hope this helps. If you will use this material, please quote me as the source, as these data are included in a book manuscript of mine.

Despite the theoretical performances allowing the Rumanian interceptors to catch the Hungarian intruders, the fact is that this never actually happened. The Hungarian recce crews could map the entire Transylvania for an upcoming war in 1940, which actually never happened.

Gen. Dénes

This post has been edited by Dénes on May 01, 2007 06:39 pm

Prompt as always… Thank you very much, Denes!

But are there any suppositions about why this didn’t happen (insufficient training of the pilots, political reasons)?

A somehow off-topic question: in some aviation modeling representation (see bellow), the Romanian He 112 have a 2-blade propeller. Was that the case? From what I know, the "original" German Heinkel machine (and those examples used in Spain and, for a short period, in the Luftwaffe) had a "modern" 3-blade propeller.

If the representation is correct, what could be the reason for which (as, for example, in the case of the PZL 24 story with the same 3 and 2 blade propellers) the Romanian aeronautics (apparently) willingly ordered, accepted or put in use downgraded versions of the imported/license built planes?

And a side/preliminary aspect: is, in basic theoretical terms, a three (four) blade propeller more modern/efficient than a twin-blade one, all the other things being equal?


http://sites.google.com/site/mgc151184/he-112bnr.15

http://sites.google.com/site/mgc151184/he112nr.4

http://sites.google.com/site/mgc151184/he-112bnr.10

No series-manufactured He 112 was fitted with a three-blade propeller, only two-blade (incl. those that were briefly used by the Luftwaffe and those exported to Spain, Japan, Hungary and, of course, Rumania).

More details and photos you can also find in my book on this aircraf type, published by Squadron/Signal, in Texas, USA, in 1995, IIRC.

Gen. Dénes

It is a common misconception that the Aeronautica Romana was equipped with poor/obsolete aircraft.

At the time when particular aircraft were purchased, such aircraft were reasonably adequate and fairly up-to-date for the time. For example PZL24 was an all-metal aircraft at the time when many contemporary aircraft (let's say the Hurricane) were made of wood and fabric.
These aircraft became obsolete as the war moved on, and by that stage they were replaced with more up-to-date aircraft. Aeronautica Romana constantly upgraded/updated their aircraft throughout their involvement in the war.

You must also consider that at the time when Romania purchased the He112, it was a better aircraft than its contemporary Bf109B. The Bf109 was chosen as the main fighter for the Luftwaffe for a number of other reasons (such as ease of construction and repair as well as Willy Messerschmitt's political connections). With ulterior improvements, the 109 superseded the 112 which received no further improvements and was abandoned. One can only speculate what would have happened were the 112 chosen as the main Luftwaffe fighter and went through all the improvements that the 109 went through.

Aerodynamically, adding more blades to the propeller of an aircraft without changing any other characteristics (such as power or weight) will not improve performance. Adding an extra blade will actually increase drag and slow it down. Picture the spinning propeller spinning in the air - the blade covers every position of the arc at more or less the same time, and this creates what can be described as a relatively dense "shield". As the air is pushed back by the propeller and the aircraft moves forward, this "shield" also meets the oncoming air and actually behaves as a brake. Adding an extra blade to the propeller will actually increase the density of this "shield". However, as the weight and power of aircraft increased due to extra armament, ammunition, fuel, the power had to increase and in order to distribute this power more efficiently, the number of propeller blades also had to increase, which in turn increased the drag that had to be compensated by more power which in turn had to be distributed to a propeller with more blades and so on in a never ending vicious circle. By the end of WW2, the technology of propeller-driver aircraft had been pushed to a limit that could not be exceeded.
Theoretically speaking, the only way to reduce this drag is to reduce the number of blades as much as possible. Hence the jet engine...

HTH
Radu

Denes, thank you for your prompt feed-back!

Radub, thank you very much for taking your time to write such a detailed answer!