Irbitis MI-02 engine for the VEF I-19 design

Hardrada55

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I've read what I can find about Karlis Irbitis' I-19 fighter design supposedly powered by a 36 litre, 36 cylinder engine allegedly based on three engines slaved or ganged together to make one large air cooled engine. These engines are variously described as 3 de Havilland Gipsy Six engines or 3 de Havilland Gipsy Twelve engines. http://www.secretprojects.co.uk/forum/index.php/topic,4945.msg39198.html#msg39198

But I can't see how these engines add up to the described 36 litres and 1800hp at "take-off" and 1470hp at 3250rpm at 3670m.

Three Gipsy Six engines would amount to 1680ci and 27 litres and if ganged together about 600 hp running at about 2350 rpm. Weight would be about 639kgs or 1405lbs. Not enough horse power.
https://en.wikipedia.org/wiki/De_Havilland_Gipsy_Six

Three Gipsy Twelve engines would amount to about 3363ci and 54 litres and if ganged together would produce about 1275hp at 2450rpm. Weight would be about 1440kgs or 3168lbs. Way too heavy.
https://en.wikipedia.org/wiki/De_Havilland_Gipsy_Twelve

Three Czech Walter Sagitta engines from 1937 would amount to 3363ci and 54 litres and would produce about 1620hp at 2600rpm at 4000m. That sounds more like it in terms of horse power. Weight would be about 1116kgs or 2455lbs. Still kinda heavy.

Three Italian Isotta Fraschini Delta from before WW2 would be around 80 litres or 4885ci and would produce about 2250hp at 2600rpm at 4000m. Weight would be about 1530kg and 3366lbs. Again very heavy.

If three Ranger V-770s from 1940 were slaved together it would provide about 37.8 litres or 2319 ci and would produce about 1560hp at 3150rpm. Weight would be about 992kgs and 2184 lbs.

The Argus As 410. If three of these were more like what Karlis Irbitis envisioned in using they would provide about 35.8 litres or 2187 ci and 1377hp at 3100rpm. Weight was about 945kgs and 2079 lbs. The Argus As 411 was a little more powerful and could provide 1776hp at 3300 rpm with a weight of 1155kgs or 2541 lbs.

Lastly, The Hirth HM 512. Three HM 512 engines provided 35.82 litres or 2186 ci and 1200hp for take off and about 1080 hp at 3000 rpm. Weight was about 810 kg or 1782 lbs.

Three Hirth HM 512 engines ganged together seem to come closer to providing the requisite power than 6 of the Gipsy Six engines or 3 of the Gipsy Twelves. I think the engine for the Karlis Irbitis' VEF I-19 was not a de Havilland Gipsy but was probably a Hirth HM 512 or an Argus 411 or maybe a Ranger V-770. I wonder how the literature on this came to say it was a de Havilland Gipsy engine?
 

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VictorXL188

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It's funny that I was looking at this design earlier today, and when looking at the attached profile view, I thought that the engine that first came to mind, when looking at the twin exhausts on each side, was a Napier Dagger, another combination engine as it were!
 

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WJPearce

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"Of Struggle and Flight: The History of Latvian Aviation" is a book written by Karlis Irbitis, designer of the I-19. The first attachment posted is page 155 out of this book. The last sentence on page 154 says "After returning to Riga I began to consider the possibility of a high-powered fighter with a hypothetical engine having six Ranger-type cylinders."

As you say, the math does not work. But, the designer himself said "Ranger-type" cylinders.

The Gypsy engines were used in his I-15a and I-15b aircraft. The I-16 used a Walter Sagitta.
 
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