Talk:Free-turbine turboshaft

External images
External images
	Reverse Flow Free Turbine
	Reverse Flow Free Turbine
	Reverse Flow Free Turbine

Aviation

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Need the correct engine graphic[edit]

There are significant differences between a free-turbine turboshaft and a standard turboshaft. Currently, the graphic pictures is of a standard turboshaft, and a grossly oversimplified version of it at that. The entry needs something along the lines of this article.Clepsydrae (talk) 02:06, 28 December 2018 (UTC)[reply]

The image here at present is clearly a free-turbine. Also it's highly simplified, but that's deliberate, so that it clearly shows the functional components. A photorealistic drawing would be no better than a photograph. Andy Dingley (talk) 09:35, 28 December 2018 (UTC)[reply]

reverse flow[edit]

Found this version which explains some turbo prop exhaust. [1] for example Pratt & Whitney Canada PT6 see [2].

--Kitchen Knife (talk) 22:04, 11 March 2019 (UTC)[reply]

Is this in relation to the other threads?

Talk:Gas turbine#Looking for explanation of 'Reverse-Flow Turbine'

Talk:Combustor#Reverse-Flow

Andy Dingley (talk) 21:19, 13 March 2019 (UTC)[reply]

Not really in the case of Turboprops the entire engine is reversed. The hot end at the front and the intake at the rear. See https://www.youtube.com/watch?v=xRnuqQbYur4 & https://www.boldmethod.com/learn-to-fly/systems/how-a-turboprop-engine-works/ it means no long shaft taking power from the back along the length of the engine to the prop and it explains why how some aircraft have the exhausts very close to the prop.--Kitchen Knife (talk) 21:34, 13 March 2019 (UTC)[reply]

Not in all turboprops though. Although for small turboprops, the PT6 has a market leading position, so many turboprops (by count of engines) are of this reversed layout. Andy Dingley (talk) 23:12, 13 March 2019 (UTC)[reply]

The General Electric H80 Diemech TP 100 and the S version of the Motor Sich MS-500V seems to.--Kitchen Knife (talk) 20:57, 15 March 2019 (UTC)[reply]

So what's the main point here? That all free-turbine turboprops are reversed? That all non-reversed engines are single- or sometimes twin-shaft non-free turboprops? You might be right, but does that need a specific source for it, or can it fall under WP:BLUE?

This isn't a point I'd really thought about before, but I think that might well be the case. Apart from the Proteus, the T53 and the TP400, I can't think of that many non-reversed free-turbines (as fixed-wing turboprops - there are plenty as helicopter turboshafts, where a rear shaft is appropriate). It's worth mentioning, but how strongly can we word this? Andy Dingley (talk) 23:54, 15 March 2019 (UTC)[reply]

the bigger and engines see more like to be hot at the rear. Allison Model 250 is even weirder.--Kitchen Knife (talk) 11:25, 16 March 2019 (UTC)[reply]

I think you have it about right It just a far more elegant solution than a long shaft. On bugger engines based on a multi-spool core, there is less of a problem and there may be problems with exhaust ingestion if they are mounted backwards plus you cannot take full advantage of any residual thrust.

Second potential advantage?[edit]

Maintenance on the PT6 series is simplified because the free turbine section can be removed while leaving the gas generator etc. in place. I gather this is made possible by the fact that it is a free turbine design. I assume not all free turbine engines take advantage of this, but it seems like a significant benefit that depends on the free turbine design. Squeakycascade (talk) 18:44, 12 August 2020 (UTC)[reply]