EC120 Diesel
 

Aviation Week reporting Eurocopter recently announced that it will re-engine an EC120 light helicopter with an advanced diesel engine under the European Union's Clean Sky joint technology initiative. The goal is to reduce specific fuel consumption (SFC) 30 percent, and emissions of carbon dioxide by 40 percent and nitrogen oxides by 53 percent, says American Eurocopter CEO Marc Paganini.

...whilst covering eveyone below in soot :E


Great torque on diesels (per cc/rpms), and very low stressed engines. The weight and (certain) vibes to deal with though.

Is it going to be a diesel - diesel engine, or diesel fueled turbine ?

The most powerful aviation diesel design I know have only 300shp and is heavier than the RR300, so I can't see it happening.

Redesigning combustion section on existing engines, to be optimized for the Eco-Diesel fuel would be probably more useful.

Interesting, Brian. Here is a general PDF on the Clean Sky initiative:

http://www.cleansky.eu/upload/downlo...aWestland).pdf

Actually diesels are overdue a revolution in combustion technology, which will reduce how much the weight nibbles into payload. The improved fuel economy helps because it reduces fuel load. As for soot, see tier 4 ground vehicle requirements, where the latest oxidation catalysts and common rail injectors have reduced this to a historical footnote.

I'll keep an eye on this story. :ok:

Swashplate engine?

It's about time!

http://en.wikipedia.org/wiki/Swashplate_engine

And if you thought a diesel robbo was exotic, would you believe me if I said there is a gas turbine torpedo?

I wouldn't have done either, but here it is! Otto II fuel, now there's a concept!

http://en.wikipedia.org/wiki/Spearfish_torpedo

Gas(heated compressed air) turbine torpedoes have been around for about 100 years.

There was a German torpedo built during WW2 (can't remember it's name) that used a V8 and consumed it's own exhaust gases, boosted by oxygen held under pressure in the torpedo, thus giving no bubbles. Very impressive for it's time, even given the limited operating life (!) though I'm not sure what it would have done to buoyancy during the run........

I believe it arrived a little bit late for service, but did well in it's trials.

Torpedo Engine,

I once imported from Sweden for a client a packing case full of engine bits from allsorts of engines, one in particular foxed us until we asked the client what it was, and indeed it was a pressurised gas operated V8 made entirely of Brass, Phospher Bronze and Copper, nil lubrication system( as it would lonly run once) and the carnk case took the shape of the diametre of the body of the Torp which looked like it could have been about 30" Dia, very strange looking V8 , all screws, nuts amd washers were also Non ferous metal, it weighed about 250Kilos.

Peter R-B
Vfrpilotpb

If engine weight is allowed to increase, i'm suprised there isn't a renewed effort to investigate turboshaft engines with regeneration. This ais used commonly in ground based power turbines, although heat exchanger mass is the limiting factor for aircraft. It would also be possible to design the optimum efficiency for medium power setting, with reheating and intercooling used to provide hover power requirements.

See page 6 of the following:
http://files.asme.org/IGTI/101/13001.pdf

More general info:

http://www.energysolutionscenter.org...ombTurbine.htm

http://web.me.unr.edu/me372/Spring20...generation.pdf

From what I've read a straight diesel. Can't see a diesel-fuelled turbine justifying a tech demo program (fill it up and fly away).

Not true. Dave Jackson probably has better insight, but there are several more powerful designs in development, incl. 450shp & 600shp units. You'd have thought that 21st century diesel tech would be able to at least challenge the 1960s technology in the RR300 (C20), but who knows. DARPA was planning to go diesel on the A160 Hummingbird at one time, but this effort seems to have stalled, with a switch to a P&W donk.

Since Westland is also involved in that Clean Sky effort, I look forward to seeing a diesel-powered EH101 with BERP IVs before too long. :E

I/C

Guys, common rail technology is the answer to the diesel critics.

Put simply, historically petrol "burned" while diesel "exploded" hence heavy diesel engine weights.

Common Rail technology now allows diesel to "burn". Given the 50% efficiency gain in terms of heat engine output that compression ignition (diesel) has over spark ignition (petrol) its only a matter of time before petrol becomes obsolete.

A modern diesel engine has no weight penalty and a huge power advantage, especially for torque focussed applications such as helos

Big change coming IMHO.

Curveball... what about the sidestick Helo EC are working on...

These sound like admirable goals but I seriously question the ability of any combustion engine process of any technology to deliver all of them.

Specific fuel consumption can be reduced because, for a given amount of fuel energy, thermodynamic efficiency determines how much of that energy can be harnessed and diesels have a clear advantage. Nitrogen oxides are often worse in diesel engines as the conditions of their formation - heat and pressure - are what gives diesels their thermodynamic efficiency, though a catalytic converter could be used to lower these.

But reducing carbon dioxides in a hydrocarbon-based fuel burned with air is an oxymoron if there ever was. Unless they're proposing solid carbon or carbon monoxide as an end products (which bring with them entirely different sets of problems), this is impossible for any isomer of any hydrocarbon of any molecular mass, or any stochiometric combustion efficiency, whether a catalytic converter is used or not. American Eurocopter's engineers may be quite good, but they cannot change fundamental chemical processes.

The other item I often don't see mentioned when talking about diesels is the basic fact that a given volume of diesel fuel has more energy in it to begin with than does the same volume of gasoline/petrol.

Quite true ... in more ways than one.

Bob

A big problem I see with this one is varying fuel standards. EU diesel & US diesel for example are years apart, let alone other parts of the globe.

That shouldn't be a problem, as you can use Jet-A in diesels.

Relyon, some interesting thoughts there...

Most engines now aim to keep combustion below 1800-2000 Kelvin (depending on peak pressure), since this is the temperature where NOx forms. Common rail reduces peak temperature (by allowing injection during combustion), and and Exhaust Gas Recirculation reduces free oxygen. The downside is (like the turbine) limiting combustion temperatures also limits thermal efficiency, but the latest Volvo trucks engines are up to about 45% total efficiency (almost as good as ship prime movers of 50%). The future will bring particulate oxydation catalysts and NOx Selective Catalytic Reduction.

VolksWagen have done a lot of interesting work on high turbo boost petrols, where the patial load choking losses can be reduced by simply altering boost. In fact per kg petrol, diesel and kerosine are very similar in specific energy, but you are right about there being some volume advantage to the heavy fuels.

The limiting factor for turbo-diesel power/mass is the shear stress on the piston skirt, which undergoes mixed wet/dry lubrication. Crosshead designs help, but to my mind more innovative crank mechanisms are ultimately required (perhaps epicycloidal for aero usage). The ultimate will be laser initiated combustion, which should alleviate the traditional diesel knock (which is actually the sound of the piston being banged over centre at TDC).

The feature of increased turbo boost (with the required intercooling) is the reason that i am suprised turbine manufactures aren't revisiting regeneration. Heat exchanger technology has progressed, so that lighter designs are now possible. A simple interim solution would be to use reheat for short duration high power requirements - this would make the core engine more efficient in cruise.

would be nice safe some full cost

I'm curious about how this is fuelled
 

Whether it uses conventional(ish) automotive diesel, or is a diesel cycle engine running something like CNG or LNG. I have a liking for CNG, to the extent that I'm researching building a car to run it, and it offers excellent performance for an engine that is optimised for it.

Major disadvantage is it's storage volume is quite large for it's weight, which means filling up the baggage space in an R66 with fuel tanks instead of engine......

CNG will also require access to reasonable supplies, which is why it's widely used as an automotive fuel in developing countries without oil but reasonable gas reserves. Since CNG is methane (settle down, the smell comes from other additives that YOU put in it) it can actually be generated naturally and to a certain extent sustainably.

Oh stop sniggering!

Run / shutdown - cold soak - restart & run to FLRS...
 

Potentially next big thing in helicopters about to take to skies:

http://www.ainonline.com/sites/defau...elpicture2.jpg

Europe?s Diesel Demonstrator To Fly This Year | Aviation International News

Engine developed by these guys:

http://www.teos-engineering.com/mbFi...age-mobile.jpg

http://www.teos-engineering.com/mbFi...05-image-3.jpg

TEOS POWERTRAIN ENGINEERING

Fadec developed by these guys:

http://upload.wikimedia.org/wikipedi...gine_AE500.jpg

Austro Engine - Home


Engine is V8, but TEOS imply V12 would be possible. Are we about to see an industry swing back to piston? Since Turbomeca gave it some thought at least, are we about to see a new breed of hybrid turbine-diesels? What else might be in the pipeline, and does it involve area 51?


(Last point was tongue in cheek, to keep discussion light hearted)

Ran a Bell 212 on arctic diesel once for about 3.3 hrs. Puffed a bit of smoke but ran great. She got and engine wash afterwards, no biggie.

..and just when I thought twin turbine time is the 'open sesame' experience I'll still have to gain, then come these and there'd be 'diesel time' figuring in CVs. :eek: