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Author Topic: Su-2 Engine position in cowling  (Read 2327 times)
warhawk
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« on: August 16, 2016, 10:45:30 PM »

Hi,

I've been looking at some Su-2 cutaways, and one thing that struck me odd was the position of the engine - why is it so deep inside the cowling, and not nearer to the edge as usual?
Or the other way around - why isn't the cowling (and the prop axis) shorter?

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Massimo Tessitori
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« Reply #1 on: August 17, 2016, 11:51:26 AM »

Hi,
maybe for a long reduction gear?
Regards
Massimo
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John Thompson
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« Reply #2 on: August 17, 2016, 04:51:52 PM »

I don't know a lot about Russian aircraft engines, but it seems to me that all of the Shvetsov M-8X series of engines had this long reduction gear housing. If you look at cutaways of them, the various Lavochkin fighters using the ASh-82 (or M-82, if you prefer) show the same setback of the engine cylinders within the cowling, like the Su-2 with its M-87 and M-88. Radial engines like the M-62 with direct drive and therefore no gearing were installed much closer to the cowling face.

John
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learstang
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« Reply #3 on: August 17, 2016, 06:31:45 PM »

In the case of the ASh-82 (M-82), it may have had something to do with the very streamlined cowlings these engines were installed in, as with the La-5, the La-7, and the Tu-2. Having the engine set back from the opening allowed for a more tapered cowling.

Regards,

Jason
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warhawk
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« Reply #4 on: August 17, 2016, 09:11:32 PM »

Thanks for the explanations.

Having the engine set back from the opening allowed for a more tapered cowling.

But why doesn't it taper then on early Su-2s?
Guess we'll never get inside the minds of 1940s aircraft designers...  Wink
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66misos
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Absence of evidence is not evidence of absence.


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« Reply #5 on: October 31, 2016, 08:25:25 AM »

Hi,
not direct answer for your question but this photo nicely shows Su-2 engine:



Note part of the engine cowling on the ground behind the main landing gear.

regards,
   66misos
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Massimo Tessitori
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« Reply #6 on: November 01, 2016, 08:37:44 AM »

Hi Misos,
really a good one. Thank you for sharing it. What is your source?
All those thin rods to keep the frontal ring into position are noteworthy.
Regards
Massimo
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66misos
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« Reply #7 on: November 02, 2016, 09:31:24 PM »

Hi Massimo,
I have found it at Czech Modelforum, unfortunately without any description.
I wonder how clean is that engine.
Regards,
   66misos
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Graham Boak
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« Reply #8 on: February 28, 2017, 11:43:26 AM »

A couple of possibilities.
The long reduction gear housing could be partly to allow for fitting of a cooling fan or shutters.
The shorter nose on early Su 2s could be because they didn't have the M-82.
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