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PostPosted: Tue Jan 02, 2018 1:01 pm 
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Yeah, I got that the first set of descriptors were talking about an X-12 rather than a V-12 or straight 12 engine. It was the combination of that with the turbine that threw me.

Is it possible that the turbine part refers to the super/turbo charger?

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PostPosted: Tue Jan 02, 2018 1:07 pm 
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Parsing it, what about a "gas turbine supercharger", similar to a rocket engine pump.

Spin up a small gas turbine, something like 10 or 30 hp, set up as a turboshaft. Grab the intake air from the intake manifold, dump the exhaust into the main exhaust. Use the power shaft to drive a supercharger for the main engine. I'd have to work through the compression ratios to see how effective it would be, and there would likely be some degree of turbo lag, but it would be a neat single box solution to compressing the intake air. Just provide a gas line and electrical power for starting, instead of having to fiddle with a PTO for a normal supercharger or exhaust manifold hi-jinks for a turbocharger.

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PostPosted: Tue Jan 02, 2018 9:52 pm 
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I realize the Stryker armored fighting vehicle is not a tank but one variation of the Stryker family is the M1128 Mobile Gun System. Can the experience with this weapon system be applied to an evaluation of the T-14.

https://en.wikipedia.org/wiki/M1128_Mobile_Gun_System


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PostPosted: Tue Jan 02, 2018 11:52 pm 
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KDahm wrote:
Parsing it, what about a "gas turbine supercharger", similar to a rocket engine pump.

Spin up a small gas turbine, something like 10 or 30 hp, set up as a turboshaft. Grab the intake air from the intake manifold, dump the exhaust into the main exhaust. Use the power shaft to drive a supercharger for the main engine. I'd have to work through the compression ratios to see how effective it would be, and there would likely be some degree of turbo lag, but it would be a neat single box solution to compressing the intake air. Just provide a gas line and electrical power for starting, instead of having to fiddle with a PTO for a normal supercharger or exhaust manifold hi-jinks for a turbocharger.


I'm probably wrong but it sounds like its using some of the same concepts of the turbo-compound engines post-WW2? Instead of the reciprocating engine driving the compressor you have a mini gas turbine doing it. https://en.wikipedia.org/wiki/Turbo-compound_engine

What kind of advantages would this design have over the standard gas turbine?


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PostPosted: Wed Jan 03, 2018 1:48 am 
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I'd assume it'd be fuel consumption. Gas turbines are thirsty, thirsty buggers (note Stu's comments on why gas turbine propulsion for merchant ships has never caught on aside from LNG tankers, which use burnoff that would otherwise be 100% wasted for fuel), and as I recall the Abrams takes a significant range penalty on account of said thirst.

If you have a turbine-compound supercharger, it lets you 'cruise' with piston-engine efficiency, and you can 'kick in' the supercharger when you need to execute a tactical GTFO Maneuver. If the supercharger is only intended to be used in extremis, having it not mechanically geared to the engine has advantages, as KDahm pointed out - also, I wonder if it allows for easier 'fine tuning' of boost. Instead of selecting from a few gear settings for your boost, you can more or less infinitely throttle the turbine if you only need a little, or a lot, of boost at the moment.

Also, I can see it having the ability to be used as an APU; if you're sitting around in a laager and don't plan to move the tank all night, you can run the turbine to generate power without putting wear and tear on the main engine.

The catch, of course, is that (AFAIK) nobody has actually done this before, so you're potentially opening up cans labeled 'here be dragon-worms'.

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PostPosted: Wed Jan 03, 2018 3:21 pm 
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The Bushranger wrote:
The catch, of course, is that (AFAIK) nobody has actually done this before, so you're potentially opening up cans labeled 'here be dragon-worms'.

The French have, in the so-called 'Hyperbar' X8 on the Leclerc. It does seem to offer the best of both worlds, subject to cost and reliability concerns.

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PostPosted: Thu Jan 04, 2018 1:10 pm 
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I'm pretty sure that if the T-14 had some novel power plant they'd be hyping it as much as they're hyping everything else. The blurb provides accurate but unconventional description of an intercooled turbodiesel. It is not a description of a turbo-compound engine.


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PostPosted: Fri Jan 05, 2018 10:08 am 
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So its a translation thing then?

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PostPosted: Fri Jan 05, 2018 10:22 am 
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Belushi TD wrote:
So its a translation thing then?


Possibly but its a common thing for "official" pieces of trade literature to describe existing technology using an unconventional vocabulary, usually preceded by the words "new and radical" (which means we finally caught up with everybody else) often supplemented by the word "revolutionary" (meaning "it doesn't work yet") For example, the French described one of their air-to-air missiles as having a "new and revolutionary electromagnetic guidance system" which turned out to be a bog-standard semi-active radar homing system that had been in service with everybody else for almost a decade. It was new to them though since their previous attempt at a radar homing missile was a beam-rider. The Germans did the same thing when they announced their "new and revolutionary 'far-field magnetics' submarine location system. It was a fairly standard MAD system although it did have a twist than made it a bit more sensitive than most. That wasn't necessarily a good thing though.

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PostPosted: Fri Jan 05, 2018 10:31 am 
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Francis Urquhart wrote:
The Germans did the same thing when they announced their "new and revolutionary 'far-field magnetics' submarine location system. It was a fairly standard MAD system although it did have a twist than made it a bit more sensitive than most. That wasn't necessarily a good thing though.


Let me guess: gain in sensitivty at the cost of ability to discrimnate between magnetic anomalies that are viable targets and magnetic anomalies other than viable targets?

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PostPosted: Fri Jan 05, 2018 11:36 am 
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Poohbah wrote:
Let me guess: gain in sensitivty at the cost of ability to discrimnate between magnetic anomalies that are viable targets and magnetic anomalies other than viable targets?

Bullseye. Also, detected a lot of minor contacts that clogged up the tactical picture while they were being classified.

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PostPosted: Fri Jan 05, 2018 5:04 pm 
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RLBH wrote:
The French have, in the so-called 'Hyperbar' X8 on the Leclerc. It does seem to offer the best of both worlds, subject to cost and reliability concerns.


According to the Hunnicutt book on tanks its fuel consumption is much higher than anticipated when it was designed. So much so that the export versions have gone for the MTU powerpacks now becoming pretty much standard (Leopard, Korean Kx, New Japanese one & Turkish Altay).


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