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V12 Diesel

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gofastclint

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The Volkswagon group have released a light weight (for a diesel) V12 that produces 500hp and 738 lb-ft. it is in the Audi Q7 and one of the VW Touareg models.

Eventually some people will crash these cars and the motors will becomes available on the secondhand market.

Question is, who will be first to put one in an aircraft and what types of aircraft would best suit this engine?
 

PTAirco

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Me!!

Actually V12 is not an accurate term here - they call it a W12, since it resembles two narrow V6s stuck side by side. I want one .....
 
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DaveK

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The VW V10 diesel is aluminum block and head with a cast iron "bearing tunnel" thing supporting the crankshaft at the bottom. So for a diesel it is very lightweight, somewhere in the 400lbs range if I remember correctly. I haven't seen anything about a W12 diesel. 400-450lbs for 350hp isn't too bad.
 

gofastclint

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530 pounds is quite a bit.. is that as pictured above??
Not sure, but that figure was thrown around on some forums. Apparently the race versions long block weighs 201kg (5.5L), the new engine shares the same construction basics as the race engine and i cant imagine just the basic accesories weighing too much. being the smart weight saving aero people that we are i bet the accessories could be custom built lighter, for example, centrifugal superchargers are alot lighter than turbo systems.
 

gofastclint

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oh the joys of diesel, more than twice the engine life, great ecconomy and they can run on jet fuel, eliminating the whole ethanol debate.
The perfect "take it easy" engine.
 

PTAirco

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I love Diesels, but I doubt this one will see "twice the engine life" - it's all a function of how highly stressed an engine is and this one seems pretty much up there. Still, that would be a great engine on a fast, long range airplane where the saving in fuel weight makes up for any extra engine weight. And even with the addition of a propeller drive , that would not be a particularly objectionable weight for that power.
 

jumpinjan

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Oct 3, 2004
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Dayton OH
V12 that produces 500hp and 738 lb-ft.
Redline = 4500rpm
HP=500
Torque = 583.5 lb-ft
That's what I get; Not 738lb-ft
Jan (Too good to be true)
(Or its a flat torque of 738lb-ft, in the range of 1750-3250rpm; That range gives 245-456HP. I just don't understand how they get that fabulous performance?)
 
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gofastclint

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I don't understand manufactures claims of torque and power. Arm't they both linked by rpm. Quite possible that the marketing department and the engineers don't chat on these finer details.

Someone once told me that Torque was and motors ability to maintain rpm under load. Is this true?
 

PTAirco

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It's really quite simple - Torque, power and rpm are all linked :

(Torque x RPM) / 5,252 = Horsepower

You can re-write the equation any way you want, but in essence what it means that an engine that can produce , let's say, 100 hp at 2500 rpm has twice the torque of an engine that produces 100hp at 5000 rpm. They both produce the same power, will use the same amount of fuel and are capable of performing the same work.
 

Jman

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Does anyone have a Torque or HP curve for this engine?

Also, what attributes are required in an engine that makes it's peak HP at direct drive RPMs vs. an engine that makes it's HP at much higher RPMs, like most Automotive engines? Is it just a matter of stroke length and bore size? Or is there more to it than that?
 

PTAirco

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Caveats apply to the "same amount of fuel", of course.

Well, yes, you could argue about that - a high RPM engine ought to see more frictional losses and some other factors come into it, but the bottom line is; making one HP for one hour will swallow about 0.45lbs of fuel (for gasoline engines) and about 0.35-0.4 for Diesels. If you look at the SFC figures for various engines since the dawn of time, it is amazing how little this figure has changed. The Wright 3350 from the late 40's is still one of the one most efficient gasoline engines (0.36lbs/hp/hr), and nobody has yet beaten the Napier Nomad ((0.34lbs/hp/hr) for Diesels. (Marine Diesels are differnet story - 0.24 has been achieved with some!)

Every fraction of a percent of increase in efficiency since then has been hard fought for and it astounds me that once you strip off all the glitz and fancy computer stuff of modern engines the engine is underneath is really only a marginal improvement over 1940's technology.
 

addaon

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Agreed. Just wanted to clarify, since your other equivalences were by definition, but the fuel usage one is based on similar (which, as you mention, is quite common!) efficiencies.
 
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