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FMA I.Ae.38

The cargo-plane in Argentina

This airplane is one of the Horten designs i like the most because of its odd shape, its many innovations and its sad story about good design and bad choices by the decision-makers.

It all started with a governement military man who asked Reimar Horten, who went to Argentina after WW2, to design a cargoplane. The wings were similar to those of the HII. Only twice as large. Reimar Horten designed it without vertical surfaces. 

But the Argentian pilots didn't want to fly it if it had no vertical fins to counter yaw in the case of a malfunctioning engine. So Reimer added the demanded fins. They were placed at 80% of the wingspan. They only deflected outwards.

I just wonder ... would it have been possible to fly it on three engines without those fins?

 

The original intended engines had 750 HP each. But they were not available. The officials ordered to use domestic engines and that could only lead to the use of engines with only 320 HP each. It made the airplane SERIOUSLY underpowered.

The testflight by Capt. Ballado. Soon after the 4 testflights the airplane was put on inactive and was stored outside. The elements had their go on it for years before it was finally destroyed by fire (arson?).

The cargo doors were innovating for that time. They could be partly openend in the air too for parachute drops. In these designs the placement of the center of gravity is very important, so it had a device that measured the loading on the wheels to indicate where the CG was during loading. Once CG was within the limits, stability would have been good ... if it was not underpowered.

Securing the load in a cargoplane is also very important. In the USA, the load became unfixed during a testflight of another experimental airplane, the XCG-16. It made the CG go outside the limits and the glider became unstable, crashed, killed all inside. This Horten design had a internal room of 30 m3. 

Clearly visible is the twist in the wing. The airfoils seems to get pointing downwards to the wings tip.

 

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