Designed by engineer and professor José Ortuño Garcia and built by the INTA media, it provides interesting ideas with a view to obtain a reduction in specific consumption and lowering the exhaust noise level of aviation engines. This was in 1994.

“MCD-2E concept”

“Ortuño engine, general view”

-It has two rows of three cylinders each and is air cooled.

-It gives 140 hp at 1,500 rpm. This engine expands the gases in a more effective way as it is double.

-It is known with reference MCD-2E that indicates “Motor de Carreras Distintas - Doble Expansión” (Motor of Different strokes - Double Expansion).

"Scheme of interior kinetics"

- (1) As shown in the figures, the crankshaft journals describe a 3-lobe hypocycloid curve generated by a point linked to a pinion that rolls inside a ring gear concentric with the center of the engine shaft or of the propeller.

- (2) This curve has 3 axes of symmetry at 120° and from the same point there are connecting rods that actuate each piston placed on 3 offset axes at an angle of 4° with respect to the 3 axes of symmetry of the curve.

- (3) Each piston has 2 Top Dead Centers (TDC): one for compression S ”and a higher one for total expulsion S of burned gases. And two Bottom dead Centers (BDC): one at end of intake I and another lower one at end of expulsion I ”with double length of the intake stroke.

- (4) Because the expulsion of burned gases is total, due to having this higher top dead center of the piston, it is not necessary to cross valves, and filling and power is improved as all the burned gases are expelled from the cylinder.

-Author's Note: The last four paragraphs (1 + 2 + 3 + 4) are a literal translated copy of the description of the engine that exists at the Cuatro Vientos Air Museum in Madrid.

“The Ortuño at the Cuatro Vientos Museum”

From Appendix 7: We located patent 249247 of the "Different Stroke Engine" as mentioned in the specification.

-This idea was exposed in a similar way in another previous patent, 230551.

-As an INTA engineer, he was able to build a prototype that today is is exposed at the Cuatro Vientos Air Museum. The main idea was to make the expansion stroke greater than the admission stroke. Almost double, by taking advantage of the law of motion referring to the mechanisms used.

"From the mentioned patent"

“Section schematics”

-Another patent for a "New Explosion Engine" was Patent 230551, filed in 1956.

-It had opposed pistons in one cylinder, they are synchronized by means of a shaft and bevel gears.

"Schematics of the New Explosion Engine"