Sovietwarplanes

Great Patriotic War Aviation => Sukhois => Topic started by: warhawk on August 16, 2016, 10:45:30 PM



Title: Su-2 Engine position in cowling
Post by: warhawk 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?

(http://www.airwar.ru/image/idop/bww2/su2/su2-2.gif)


Title: Re: Su-2 Engine position in cowling
Post by: Massimo Tessitori on August 17, 2016, 11:51:26 AM
Hi,
maybe for a long reduction gear?
Regards
Massimo


Title: Re: Su-2 Engine position in cowling
Post by: John Thompson 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


Title: Re: Su-2 Engine position in cowling
Post by: learstang 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


Title: Re: Su-2 Engine position in cowling
Post by: warhawk 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...  ;)


Title: Re: Su-2 Engine position in cowling
Post by: 66misos on October 31, 2016, 08:25:25 AM
Hi,
not direct answer for your question but this photo nicely shows Su-2 engine:

(http://www.modelforum.cz/download/file.php?id=1245339)

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

regards,
   66misos


Title: Re: Su-2 Engine position in cowling
Post by: Massimo Tessitori 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


Title: Re: Su-2 Engine position in cowling
Post by: 66misos 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


Title: Re: Su-2 Engine position in cowling
Post by: Graham Boak 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.