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Marton X/V (RMI-8)

iverson

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Thank you for doing the scaling. It tends to confirm my suspicions.

Note how close the rear propeller of the "RMI.8" is to the horizontal stabilizer when compared to the Fokker and how the tail booms are almost identically sized in each, despite the enormously greater power andsignificantly greater weight of the "RMI.8". And note how the DB605 fills up the space between the engine and the cockpit that, on the Fokker, with its smaller Walter engines, holds the main fuel tank. The "RMI.8" would equires significantly greater volume for fuel than the Fokker. So where would it go? The wing and vertical tail surfaces of the "RMI.8" have slightly more area than the Fokker's, but given the extra weitght and power, the wing loading would have been significantly greater than the Fokker's and controllability might well be worse..

Perhaps most damning of all, where are the radiators for the two DB605s? The Walter engines were air-cooled. But for the DB605s, we need at least enough radiator area to match what we'd see on an Me210/410. But the Winkler sketch shows only a small scoop under the rear engine. What at first looks like a Bf109E radiator under the wing in the profile turns out to be a large flap when compared with the plan view. So I think that whoever created the sketch drew it based on the Fokker and forgot the crucial difference between air- and liquid-cooled engines.
 

blackkite

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I thank very much for your very sharp opinion.
 
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blackkite

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Hi!
 

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leaded50

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RMI -8 .. copy of SAAB J-21 with an extra motor in front?
 

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Justo Miranda

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Fokker D.XXIII​


The lack of indigenous aircraft engines was the main limitation of the Dutch aeronautical industry. When Fokker started the design of the successor of the D.XXI at the end of 1937, he made it taking into account that, in any future European war, it would be difficult to access the powerful 1,000 hp engines that were already being manufactured in Germany, France and Great Britain.

It was decided that the Fokker D.XXIII would be powered by two 500-700 hp engines, allowing to increase the CAP range using only one of them. A twin tail booms airframe, with short wingspan and tandem engines, was then chosen to obtain a fast aircraft. This configuration neutralised the gyroscopic coupling of the propellers and the power plants torque effect, giving the D.XXIII superior manoeuvrability compared to the Bf 110 and Potez 63 conventional twin-engine fighters. The D.XXIII could indistinctly use air-cooled engines of the types Walter Sagitta I.S.R. (528 hp), Isotta-Fraschini Delta (700 hp), Gnôme-Rhône 14 M-4 (700 hp) or liquid-cooled Rolls-Royce Kestrel V (755 hp), Hispano-Suiza H.S.12 Xcrs (690 hp) and Junkers Jumo 210 Ga (745 hp).

The project Ontwerp 156 was also considered. It was a version of the D.XXIII propelled by two 1,030 hp Rolls-Royce Merlin II which would have been the fastest fighter of its time.

The D.XXIII prototype flew for the first time in May 1937, surpassing the 500 kph and 9,000 m ceiling, propelled by two Walter Sagitta. Hit by a bomb on 10 May 1940, it never flew again.

The construction system of the airframe was the same than that of the D.XXI, but the idea was to use a wing entirely built of metal for the production version. It was armed with two 7.9 mm (synchronized) machine guns in the fuselage and two 13.2 mm FN/Browning heavy machine guns in the tail booms.
 

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Justo Miranda

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Marton RMI-8 XV-01​

When the Germans allowed the manufacture under license of the Messerschmitt Bf 109 G. The availability of the DB 605 engine induced engineer Dezső Marton of the Aviation Technological Institute to design a twin-boom push-pull heavy fighter based on the Fokker D.XXIII. The construction of the prototype, called Marton RMI-8 XV-01, with wooden wings and metal fuselage, started in 1943 but was destroyed by a bombing on 13 April 1944. It was expected to have reached a maximum speed of 580 kph and a ceiling of 11,500 m.

The armament would have consisted of a 30 mm Rheinmetall-Borsig MK 108 cannon, firing through the propeller hub, two 20 mm Mauser MG 151 installed in the boom leading edges and two 8 mm Gebauer machine guns fitted in the front fuselage. The aircraft was to have an ejection seat powered by a spring.
 

sienar

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The nose and rear fuselage of the RMI 8 drawing/s were probably taken from the Bf 109G, which had the same engine. A little artistic license would also have been needed to accommodate the retractable nosewheel (whose position is noticeably further forward than on the cutaway drawing).

Look carefully at the front gear leg, in particular the hinged wheel flap. It is an awful lot like the 309.
 

steelpillow

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Look carefully at the front gear leg
Note how close the rear propeller of the "RMI.8" is to the horizontal stabilizer when compared to the Fokker

In which drawing/s? Everybody's renderings vary, none is genuine. For example these criticisms do not apply to the comparative cutaway I reposted earlier, while that has other flaws.

From what people say here the RMI programme does seem to be genuine, though nobody has offered any sources free of Winkler's hand. But the RMI-8 is so dominated by fantasy that any reality is undermined.
 

steelpillow

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On the Fokker D. XXIII, Justo's story is, sadly, part of the fairytale.

The only D.XXIII ever built had thick-chord wooden wings to speed manufacture. The production D.XXIII was to have had metal wings and to be armed with two 7.9 mm and two 13.2 mm Browning machine guns. Nor did the prototype fly until 1939, two years later than in the fairytale. Only 4 hours flying were achieved before the programme was forcibly terminated by hostilities. Engine cooling problems were experienced (as almost always happened with fuselage-mounted pushers).

The maximum speed reached is not reported. We may note that the two Sagitta engines delivered a total of just over 1,000 hp, about the same as the contemporary Merlin I. The rear prop would have lost significant thrust operating in the turbulent wake of the front prop (as Dornier experienced with the Do 338). Moreover the D.XXIII had a thick wooden wing and twin tailbooms. Expecting it to go faster than the Hawker Hurricane I's 508 km/h was and remains wholly unrealistic. I'll eat my hat if it beat the 500 km/h mark during those 4 hrs of flying engine trouble.

Given the peripheral status of the RMI in the Nazi war machine and the dire problems Germany was having in getting viable aero engines to stay in the air, making examples of a state-of-the-art front-line type available to the RMI would certainly have been discussed at a high level by the German command and industry. Records of their discussions survive and the RMI is conspicuous by its absence. The thing may or may not have been proposed by Marton, but that it was carried out beggars belief.

Seriously, most of this thread belongs in a What-If forum, not here in Secret Projects.
 

Tzoli

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Sadly László Winkler who held these drawings and possibly documents died in 2001 (born 1926) so getting the official materials will be difficult.
There is a book mentioning the Varga RMI-8 aircraft:
Bonhardt Attila - Sárhidai Gyula - Winkler László (1989 and/or 92): A Magyar Királyi Honvédség fegyverzete.
Zrínyi, Budapest. pp. 450–451. ISBN 963-327-182-7

And an online article downloadable here:

or the first google found here:


Both are in Hungarian Language. If requested I can translate the pdf's associated part for the RMI-8 (pp 20-26)

And some comments in this forum might provide extra info as the wegiths associated with the aircraft most likely be for the lighter test aircraft not the final would had been production plane:
Again I can help with translation
 
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