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Brian Abraham
7th May 2008, 12:15
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.

Overdrive
7th May 2008, 15:13
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.

Lt.Fubar
7th May 2008, 15:45
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.

Graviman
7th May 2008, 20:14
Interesting, Brian. Here is a general PDF on the Clean Sky initiative:

http://www.cleansky.eu/upload/download/17/en/GreenRotorcraftITDGiuseppePagnano(AgustaWestland).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:

Agaricus bisporus
7th May 2008, 20:25
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

ApocalypseThen
8th May 2008, 04:20
Gas(heated compressed air) turbine torpedoes have been around for about 100 years.

Freewheel
8th May 2008, 06:23
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.

VfrpilotPB/2
8th May 2008, 08:28
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

Graviman
8th May 2008, 09:29
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/DistGen/Tutorial/CombTurbine.htm

http://web.me.unr.edu/me372/Spring2001/The%20Brayton%20Cycle%20with%20Regeneration.pdf

Ian Corrigible
9th May 2008, 16:12
Is it going to be a diesel - diesel engine, or diesel fueled turbine ?
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).

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

mini
9th May 2008, 22:36
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...

relyon
10th May 2008, 01:29
... 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.
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.

... its only a matter of time before petrol becomes obsolete.
Quite true ... in more ways than one.

Bob

mini
10th May 2008, 21:14
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.

Lt.Fubar
10th May 2008, 21:27
That shouldn't be a problem, as you can use Jet-A in diesels.

Graviman
10th May 2008, 23:08
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.

HFM
4th Jun 2008, 20:59
would be nice safe some full cost

Freewheel
5th Jun 2008, 02:16
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!

Graviman
30th Apr 2014, 16:44
Potentially next big thing in helicopters about to take to skies:

http://www.ainonline.com/sites/default/files/uploads/310_dieselpicture2.jpg

Europe?s Diesel Demonstrator To Fly This Year | Aviation International News (http://www.ainonline.com/aviation-news/hai-convention-news/2014-02-23/europes-diesel-demonstrator-fly-year)

Engine developed by these guys:

http://www.teos-engineering.com/mbFiles/images/carousel/thumbs/180x160/distri-attelage-mobile.jpg

http://www.teos-engineering.com/mbFiles/images/carousel/thumbs/180x160/v1015-06-07-05-image-3.jpg

TEOS POWERTRAIN ENGINEERING (http://www.teos-engineering.com)

Fadec developed by these guys:

http://upload.wikimedia.org/wikipedia/commons/thumb/0/05/Austro_Engine_AE500.jpg/220px-Austro_Engine_AE500.jpg

Austro Engine - Home (http://austroengine.at/)


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)

Corax
1st May 2014, 01:18
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.

MartinCh
1st May 2014, 01:43
..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:

Graviman
2nd May 2014, 11:53
Corax, this piston pounder burns Jet-A1. Available from your friendly local fuel bowser.

Martin, with latest gen Fadec this system will be single control. Besides diesels don't need carb heat. ;)

Gemini Twin
2nd May 2014, 21:02
There will never be a piston diesel engine that will have the power to weight ratio of a current helicopter turbine engine. Aviation diesel engines are only practical as an option for avgas burning piston engines.
Since the objective published 6 years ago was primarily to reduce emissions by improving specific fuel consumption, by burning to fuel at a much higher temperature, the investment should be in the greater use of ceramic materials in the combustion and turbine sections of all gas turbine engines.

riff_raff
3rd May 2014, 23:53
This V12 engine has existed for a couple years. I had a chat with the company (http://www.red-aircraft.com/engines/red-a03-v12/) back in 2010. The engine was 6.1L (86mm bore x 88mm stroke), and they quoted an MCP of 480hp. It might be the same engine.

http://www.red-aircraft.com/wp-content/uploads/2012/04/red_A03.jpg

While a DI turbo diesel recip engine would definitely give excellent SFC, there are still some other issues to consider. The installed weight penalty of this complete engine system (including plumbing, heat exchangers, etc.) vs. a turboshaft engine is quite substantial. A recip turbo diesel engine would also require a heavier duty drivetrain to handle the cyclic torque impulses produced by the high combustion pressures. This engine would be quite expensive, and I could imagine it costing well in excess of $100K.

The project seems like an interesting engineering exercise, and the engine design seems to be well thought out. But the reduced SFC is not enough to justify the current weight penalty of the engine installation. We should also consider that the TE and SFC of small turboshaft engines is rapidly improving, thanks to better materials, improved compressor/turbine designs, and higher cycle pressures. So the turboshaft will likely continue to be the engine of choice for light helicopters.

Graviman
7th May 2014, 18:15
Riff,

Don't think it's the same engine, looks like a Mercedes derived aero engine(?). I'm impressed that the flight test is in a YAK-52: Those wings are relatively untwisted, which means it will be capable of flick rolls (spin entry under gee loading from say a 60' bank with tip stall that washout is normally there to reduce) so that first flight was just a gentle look-see. When you consider the problems that Thielert had with the gearbox before handing the concern on to become Austro AE4, you'll understand what I mean. That prop will generate impressive gyroscopic torques. Being a V12 should help keep crankshaft torsional vibration down, but it would not suprise me if TV was why TEOS/Airbus picked a V8 for Ironbird.


Gemini,

What you say is all true: AvTur diesel can never hope to match turbine for power-to-weight. But the benefit is that you do not have to rely on exotic materials, coatings or casting processes like you need with turbine first stages. This translates to reduced operating costs because overhauls can be less extensive, which combined with the fuel burn then reduces costs-per-hour. The RR300 developed from RR250 for the R66 was specifically designed to remove axial stages for reduced overhaul costs. The next step is to consider combining piston high pressure stage with turbine low pressure stage to get the best of all worlds: low weight, low cost, good efficiency...

wiisp
11th May 2014, 11:20
Diesel engines in the air is not really new. In the mid 30'ies, JUMO 205A diesel had 867 Hp at 595 kg.. They where used in Dornier and Blohm & Voss machines.

riff_raff
12th May 2014, 00:45
Graviman,

If my memory serves, the Rakhlin V12 was a derivative of the Audi V12 TDI engine. The engine was re-engineered to lighten it, replace the chain cam drive and accessory drives with gears, replace the turbos, etc, and TEOS may have been involved with that effort. I did a quick check and Rakhlin is proposing a price of $170K for this engine, which is about 75% of the $225K price of a new 250-C20 turboshaft of similar power.

I also liked your comment about putting a high-pressure recip combustion stage between the turboshaft compressor and turbine stages. Garrett (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19870002357.pdf) did quite of bit of work on this type of engine back in the 80's. Pratt & Whitney (http://www.flightglobal.com/news/articles/pratt-amp-whitney-wankel-prototype-to-test-by-june-325020/) has also been working on a similar approach using a Wankel rotary combustion stage.

Soave_Pilot
12th May 2014, 00:53
When I went to Robinson's safety course in 2010, Tim Tucker said before they decided to put a turbine in the R66 they tried to come up with a diesel engine to run in it but the numbers were not good, in others words too heavy per HP produced!

Just comparing, a Lycoming IO360 engine is rated at 290 HP and weights about 270kg, the RR300 turbine is rated at 300 HP and weights about 90kg. Usually diesel engines are heavier than gasoline ones.

onetrack
12th May 2014, 02:44
Perhaps the aircraft diesel engine designers will benefit from a talk to Mazda about their new SkyActiv-D low compression diesel engines.

By lowering compression to 14.0:1 and by initiating earlier injection of fuel (BTDC as compared to TDC in regular diesels), Mazda have been able to produce a diesel engine that performs more like a petrol (gasoline) engine.

The weight savings in the design of the Mazda SkyActiv-D engine are substantial, with many major components being lightened to the order of up to 25%, as compared to conventional diesels.

The additional benefits of the SkyActiv design are better fuel economy, reduced emission levels and more responsiveness.
The SkyActiv design includes Variable Valve Lift, and twin, two-stage turbochargers, that are all proven principles, that produce the best performance out of IC design.
Building NA diesels is a waste of time, diesels have to be turboed to extract maximum efficiency from the diesel principle.

MAZDA: SKYACTIV-D | ENGINE | SKYACTIV TECHNOLOGY (http://www.mazda.com/technology/skyactiv/engine/skyactiv-d.html)

Graviman
15th May 2014, 19:17
Riff, read your paper: wow!

Looks to me as if the only reason this didn't happen was because of the diffculty in convincing investors of the market. Maybe that's about to change...

Soave, Frank Robinson himself admitted that at an RAES conference I attended. The difficulty here is that you don't want to take on a new engine in a new airframe - that really only left him with the diesel engines that were in the market place at that time. Post their LeMans endurance racing experience TEOS obviously gained enough practical design experience to convince Airbus to consider an EC120 prototype.

Onetrack, the bit that auto marketing men aren't telling you here is the common rail pressure that you need to more or less vapourise the diesel on injection - I'm told that 3000bar is probably where they need to be. The real problem is that a helicopter engine must reliably chug, whir, or hum away for at least 3000 hours before major overhaul. If competing with turbines then 10000 hours is the mark. The fuel injection system tends to be one of the main limiting factors to that TBO, so you can bet your bottom dollar the aero engineers pour over the reliability data before even mentioning the word "certification".

Edit: Just noticed that last paragraph did not make it clear that Jet-A1 has less lubricity than pump diesel.

Peter-RB
18th May 2014, 13:19
A pal from the Emerald Isle's tells me he can supply Diesel at Half price, now that would make things a lot cheaper or should I say Lower Cost!!

Peter R-B
Lancashire

riff_raff
20th May 2014, 23:59
Graviman-

The results from that 1985 Garrett project were pretty impressive indeed: 2.3 hp/lb wet installed and an overall BSFC of 0.33 lb/hp-hr. Here's a link to another paper of a trade study Garrett did (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19870015890.pdf). On page 7 there is a comparison between notional 1000hp turboshaft and compound engine drivetrains operating at 4K95F conditions. Over a 2.5 hr flight the combined weight of the engine, fuel and fuel tank is 16% lower for the compound engine.

The Garrett project results are even more impressive when you consider that all of the testing was done using circa-1985 commercial mechanical diesel injection equipment. The DDC unit injectors used could produce injection pressures around 1200bar, but they did not provide accurate control of injection timing or duration. As you pointed out, just imagine how much better this compound engine would have performed using a modern 3000bar, high-frequency, direct drive piezoelectric, digitally controlled, common rail injection system.

As for your concern about the durability of such an injection system, they are used widely on modern production automotive diesel engines and provide extremely reliable service for well over 150K miles. 150K miles of highway driving would be roughly equivalent to 3000hrs operation, which would seem to be acceptable for current commercial rotorcraft service.

It would be great to see someone pick up where Garrett left off with this concept.

Graviman
21st May 2014, 18:13
Riff,

Thanks for that paper. Agreed it would be great if Ironbird taking to the sky kicked off new R&D to examine whether a modern incarnation of CCEP could generate the same level of improvement as CCEP is over the Napier Nomad (arguably first of the kind).

Perhaps I was too quick to dismiss Onetrack's mention of the Mazda approach. Certainly fuel systems able to handle kerosine are available for diesel engines, so it is not too big a leap to envisage a 3000 bar system able to cope with kerosine. The other thing to bear in mind is that diesels are efficient because of the high peak cylinder pressures, but there are other methods to reduce weight. For my money Steyr have been pretty close to the mark by avoiding a head gasket in their monoblock designs. It's no surprise that the M16 was selected by Austro for an aircraft engine (my initial thought was TEOS must be using the Steyr part bin):

http://www.mackboring.com/images/steyr-2-small.jpg from http://www.mackboring.com/CommercialMarine/Steyr_Motors_Features.aspx

SAE papers on Steyr monoblock:

Steyr Monoblock High Speed Diesel Engine Family Powerful, Cost Effective, Compact, Low Noise, Ware-Resistant and Fuel Effective (http://digitallibrary.sae.org/content/942336)
The New Generation of High Speed DI Diesel Engine with High Specific Power and Durability (http://digitallibrary.sae.org/content/951853)

riff_raff
23rd May 2014, 01:53
Graviman-

The first thing Garrett did with their CCE project was establish a baseline using the Nomad. Then they conducted numerous trade studies to determine what approach was optimum for cylinder scavenging, compressor/turbine arrangement, balance of work between the piston and turbo machinery, etc. Garret determined a uniflow (scavenge ports in the cylinder walls and poppet exhaust valves in the head) 2-cycle CI diesel core with an effective compression ratio around 8:1, combined with a single stage turbo compressor for scavenging/boosting, and a free turbine stage connected to the crankshaft by a gear set for power recovery, was optimum. The Nomad used different engine and turbomachinery arrangements than this.

A monoblock construction like Steyr's is an excellent choice for a high-pressure diesel, since it addresses many of the structural and heat transfer problems these engines face. There have also been significant recent improvements in piston rings, cylinder liner coatings, journal bearing materials, and lightweight forged steel pistons that would provide adequate service life when operating at peak cycle pressures well above 200bar. This may not have been possible just 10 or 15 years ago. But as you noted, the way the CCE achieves high efficiency is thru high cycle pressure ratios, so these developments are important.

Lastly, a 4-cycle turbo diesel would have lower thermal loading on the engine components than a 2-cycle compound turbo diesel, so it would likely have better durability. But the 4-cycle would also be heavier, and this is a significant concern for a rotorcraft application.

Graviman
24th Jul 2014, 17:55
TEOS POWERTRAIN ENGINEERING - Diesel aircraft engine (http://www.teos-engineering.com/experience/diesel-aircraft-engine/)

Iron bird testing:
http://www.teos-engineering.com/mbFiles/images/thumbs/800x600/ae-440-helicopter-aircraft-clean-sky-teos-powertrain-engineering.jpg

Not the V8 AE440, but another TEOS V12 aircraft engine:

http://www.teos-engineering.com/mbFiles/images/thumbs/800x600/aircraft-engine-v12-teos-powertrain-engineering-1.jpg

Safe to say that a lot of people are watching this one to see if it points the way for an industry shift...

Ian Corrigible
10th Nov 2015, 14:26
Diesel H120 finally flies (http://www.airbushelicopters.com/website/en/press/Airbus-Helicopters-starts-flight-tests-with-high-compression-engine-for-cleaner,-more-efficient-and-higher-performance-rotorcraft_1859.html)
Airbus Helicopters has successfully completed the first flight test of the high-compression engine demonstrator aircraft. The development and flight test of this new technology demonstrator is part of the European Clean Sky initiative’s Green Rotorcraft Integrated Technology Demonstrator (ITD) program.

Integrated into an H120, the 4.6-liter high-compression piston engine runs on the widely-available kerosene fuel used in aviation engines. Its V8 design has the two sets of cylinders oriented at a 90 deg. angle to each other, with a high-pressure (1800 bar) common-rail direct injection and one turbocharger per cylinder bank.

Other features include fully-machined aluminum blocks and titanium connecting rods, pistons and liners made of steel, liquid-cooling and a dry sump management method for the lubricating motor oil as used on aerobatic aircraft and race cars.

http://i.imgur.com/v82SmFO.jpg (http://www.airbushelicopters.com/website/docs_wsw/img/x1000/RUB_151/press_1859/EXPH-1544-176_Copyright-AirbusHelicopters-JeromeDeulin.jpg?t=©+Airbus+Helicopters%2FJerome+Deulin&tS=8)

I/C

CRAN
10th Nov 2015, 16:09
Well done to all involved. This is a very interesting and important development and I hope the program continues to make useful progress.

CRAN
:ok::)

whoknows idont
10th Nov 2015, 16:40
I doubt they will move anywhere with this. They probably just had to get it to fly in order to get their share of the €1.6bn budget of the clean sky program. It will fly for a couple of hours then will be moved to some museum or EC lobby. Then the project department will be dissolved, probably having created a respectable profit drawing public fundings...

cattletruck
12th Nov 2015, 09:13
Woulda been more sexier if they ran a set of exhaust manifolds out the side like a hot-rod.

Without looking I guess you could mistake it for a Ford Transit van when it's idling :E

whirlydude
15th Nov 2015, 17:13
I am following this project with great interest and hope it becomes viable . Why no video of the flight and i wonder how it sounds from its twin turbo v12 engine . From the picture the exhaust looks to emit very clean exhaust fumes .

SWBKCB
15th Nov 2015, 17:33
There's video of it flying in the link at post 34. Can't really tell over the musical packing but sounded OK.

Soave_Pilot
16th Nov 2015, 11:54
They've got two pilots onboard and notice how the nose is up with CG a bit aft. It probably won't fly single pilot within CG limits without a ballast.

Flying Bull
16th Nov 2015, 12:37
Hi Soave_Pilot,

seems like you missed one or two hours in ground school....
Main gear boxes and therefore main rotors are normally rigged with an angle toward the front of the helicopter - which allows more or less level seating while at cruising speed (fuselage level, rotor tilted forward for speed).
The little drawback is, that you hover tail low (rotor level, fuselage tilted backwards)
http://www.helionline.net/picture/41196/big.jpg
and I remember my Bell 206 times, with some very interesting high nose up attitudes, cause my weight was just above the weight, where you required an extra weight in front.
Slightly lighter pilots had to carry them...

additional, with a test flight, you can be quite sure, that the EC120 was filled with additional electronics, to record every possible movement, vibration, temperature and so on - which you can see in the clip, is also in the back of the helicopter.
Watched the clip and saw nothin unusual about the attitude of the helicopter.
http://www.helionline.net/photogallery/15/71/41196//4/EC120.html

widgeon
16th Nov 2015, 16:17
One hopes that the Fuel Control unit is not designed by Volkswagen Audi :O

John R81
18th Nov 2015, 09:00
I don't know.... it would give lower emissions, on paper at least :) (Just don't use the official consumption figures for any flight planning, if you want to avoid unpleasant surprises :eek:)

Soave_Pilot
19th Nov 2015, 17:05
seems like you missed one or two hours in ground school....
Main gear boxes and therefore main rotors are normally rigged with an angle toward the front of the helicopter - which allows more or less level seating while at cruising speed (fuselage level, rotor tilted forward for speed)
Thanks for the review mate. I think I can go solo now :ok:


I was talking about the CG of that aircraft. Here below you have a EC120 with 2 pilots onboard, notice how the tail is not as low as the EC120 with diesel engine. And like you said, they had more electronics in the back, take those out and you would have an even higher nose.

Happy flying


http://avia-dejavu.net/OO-EYP1.jpg

http://avia-dejavu.net/OO-EYP1.jpg

Flying Bull
19th Nov 2015, 18:30
Hi Soave_Pilot,

in the physics of my world - if you remouve weight from behind the rotor - the nose starts to drop.......

∧-------∆--------∨

:E

Soave_Pilot
19th Nov 2015, 20:01
Hi Soave_Pilot,

in the physics of my world - if you remouve weight from behind the rotor - the nose starts to drop.......

∧-------∆--------∨

:E

You are correct. But I meant back seat inside the helicopter as I thought it was referred.

SP

heli1980
20th Nov 2015, 03:03
I only have around 650 hours on an EC120 so not that many, but I've found they always run out of FWD CG. Personally I think if they did adopt a more rear heavy configuration then it may solve a few problems with CG issues.

For those solo flights just carry some ballast.

John R81
21st Nov 2015, 07:43
On my machine (floated, with my avionic fit, 1148kg empty), with just a pilot, then provided the pilot weighs more than 20kg you will be inside the rear CoG limit.


As Heli190 says, it is very easy to run out of fwd CoG on the 120 if you want to lift 5 guys. Say 4x90kg guys (Pilot and 3 pax) then I have just 60kg left in the final rear seat and then out of fwd CoG.


So weight reduction behind the mast will begin by improving both total payload and flexibility for GoG.

chopjock
21st Nov 2015, 12:23
I'm guessing the fuel tank can be designed smaller too as diesel fuel burn should be a lot less than a turbine.

John R81
22nd Nov 2015, 09:02
120 has 2x fuel tanks, one under the baggage compartment floor and the other higher. Smaller fuel load will help total weight but with the current tank locations very little impact on CoG; there is some small shift FORWARD as fuel reduces but it is minimal. If the redesign removed the front of the current tank you might reach neutral CoG from ramp-to-zero fuel.

riff_raff
24th Nov 2015, 23:38
This recip diesel engine retrofit is not fully optimized in terms of weight. In order to make use of the 120's MGB there is actually a speed increasing gearbox installed between the diesel engine and existing MGB input. The diesel engine output speed is increased and then decreased.

Here is a fairly recent presentation from Airbus Helo on the HCE demonstrator program: http://www.aerodays2015.com/wp-content/uploads/sites/20/2G-Alexandre-Gierczynski.pdf (http://www.aerodays2015.com/wp-content/uploads/sites/20/2G-Alexandre-Gierczynski.pdf) Interesting technical data on fuel consumption, emissions, and drivetrain dynamics. Also note the relative size of the heat exchanger module on slide 5. Overall a pretty nice job of packaging.

Agile
25th Nov 2015, 01:52
nice piece of information, indeed nice packaging, fully machined body, wow!, $$$.


I almost like the idea of it now. reliability question is still something that would deserve more information experience.


and then that sexy turbine spin up noise will be gone :(

Peter-RB
25th Nov 2015, 08:26
What sort of SHP is needed to be had for running the EC120, and what sort of Diesel Engine would be fitted, would it be a big six, or V6 upright or inverted, or the same with a V8 or V10, V12, the twin turbo V6 in my Jaguar develops 295 HP in normal guise but will push out near 350 if chipped and is still only weighing about 280 Lbs the torque is huge all the way through the acceleration range due to Turbo's overlapping each other,

If kept at 80 mph or below,this engine return's 38/40 mpg whilst only running at 1850 rpm it is turbine smooth, al-told this is one of the best Diesel engine's I have come across.. or are we thinking of a true Turbine burning true Diesel..?

GoodGrief
25th Nov 2015, 08:39
The EC120 turbine puts out 504hp and it's not enough.So, 550 to 600 would be good.

Agile
25th Nov 2015, 09:46
Peter-RB, the presentation above answers your questions quite well.

John R81
25th Nov 2015, 10:50
I think the 120 "not enough power" issue relates more to the gearbox limitations that the engine. Hence I can't see value in producing (say) 800 SHP from the test motor and simply trashing the gearbox.


Whilst the current approach is great for testing the motor, surely a production aircraft would have a new gearbox, doing away with the idea of a multiplier box. In that case it is a perfect time to increase the blade area and uprate overall power.


Not for "cheap retrofit" (obviously) but a very sensible solution and still minimising the additional certification / testing.

3top
26th Nov 2015, 21:26
120 has plenty enough power!

Any more and it will eat into 350B2 territory and price itself out of the market.

Funny that no one ever complains about the Bell 206 not having enough power.

Keep the ec120 inside published limits and it has plenty of power - just MANAGE the weight!

You would NEVER think about using the 96 (or was it 98??) gallons on the range-extender on a 206 and put 3 pax in there!! (it would never take off!)

But for some reason everybody thinks you should be able to fill a 120 to 110 gallons and put 4 pax in there and probably fill the trunk too AND fly off with this!!

....as long as you stay within the weight limits you fly circles around a 206, just fine - thank you!


3top :cool:

riff_raff
27th Nov 2015, 00:09
GoodGrief- The Arrius 2F turboshaft engine (http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgMakeModel.nsf/0/A0DB83BD643911AD862573BF0056046F/$FILE/e34NE.pdf) used on the H120 is rated 432shp for TO and 432shp for MCP. The HIPE AE 440 V8 diesel has a similar rating. As John R81 noted the shp rating is based on the MGB capabilities. This is illustrated by the vertical line shown in the center of the graph on slide 4 of the presentation I linked above.

John R81- Your point about the H120's existing MGB capability is excellent. One serious concern when retrofitting this recip diesel engine with very high firing pressure is the instantaneous torque profile at the crankshaft. If you look at the graph on slide 9 of the presentation I linked above, it shows a crank torque oscillation of +/-100% at 4X/rev. Turboshaft engines don't produce these extreme peak-to-mean torque oscillations, and a turboshaft engine MGB is not designed to accommodate them. To address this problem, a tuned torsion shaft was installed between the engine and gearbox.

That presentation had some great technical information. I think any publicly funded research project that does not involve some national security related subject matter should be made freely accessible to the public on a timely basis. I congratulate the EC and its industry partners on this program for doing a good job in this regard.

Agile
27th Nov 2015, 02:14
The point of the motor torque spikes compared to turbine is well taken, the magic of helicopters is that they operate a one unique RPM setting (various torque settings). as the result a tuned damper shaft is bound to give good result in a small volume. This is in opposition to the automobile where the combustion engine vibration have to be absorbed across a wide range of operating points.


The engine is 100Kg heavier, the fuel is 100Kg lighter, this could work.


I do come back to the idea, what will be the reliability and maintainability of that engine compare to a turbine?. It will take a full package of benefit to convince operator and private owners. the EC120 is a great aircraft, but it is not selling so much out of the factory anymore if I am not mistaking.


Commercially, should airbus helicopter focus on it, or make more high priced EC135/EC145.... with the growth from Eurocopter to airbus helicopter, they got bigger, they therefore have to think bigger (similar to Sikorsky/Lockeed dumping the 300).

tartare
27th Nov 2015, 03:27
Agile makes an important point.

No more electric whine of starter motor spinning compressor.
No more ticking of injectors.
No more batmobile like "whoosh" as the turbine lights.
And no more sweet smell of Jet-A1 that is so redolent of flight, like the sun through Perspex on sheepskin seat covers on a hot day, or the solid feeling of a pair of David Clarks as you clamp them on and adjust the boom mic...


It'll probably sound like a bloody bus, and smell like one too...:{

Agile
27th Nov 2015, 05:17
Yes that sounded like poetry to my ears, like a good wine, its not the drinking its the divine experience of the sense.


but think about it now:
the roar of a pure breed racing engine, those titanium rod moving in perfect unison, those twin turbo spinning to fury speed in 1/4 second and getting into a deep purple glow. the whole thing started by one of these F1 starter, that you find on the Lamborghini Aventador.


By the way that engine use kerosene, so the smell jet fuel stays.

riff_raff
27th Nov 2015, 05:47
Also consider that the recip diesel engine requires a friction clutch to allow the engine to start and then slip enough to bring the rotor up to speed. This is something a free-power-turbine turboshaft engine does not require.

Agile
27th Nov 2015, 08:51
Centrifugal clutch akin to the Alouette II,


http://www.alouettelama.com/types/318-20.jpg


from left to right: rotor brake, free wheel, centrifugal clutch

3top
27th Nov 2015, 12:04
WHO says no more JP1 smell?

You can bet on, that this thing runs on JP1...
[NO ONE would install the infrastructure to supply DIESEL for a few ec120D operators - JP1 is aready there..]

3top

whoknows idont
27th Nov 2015, 23:40
Again, I bet there will be no Ec120D and no EC120D operators. This is a demonstrator solely built to draw public funds. I can't imagine this going anywhere.
Best case scenario the engine development will be used in a different aircraft, probably fixed wing.

Agile
28th Nov 2015, 02:50
I agree AH has better things to do than concentrate on small aircrafts (EC120D) when they now have tons of capital and assets to sell EC225s and other high cost ships to the militaries of the world .


Regardless the demonstrator shows that it is possible to have a 5 seat piston helicopter without compromises (either look or performance).


In the best case Guimbal (maker of the Cabri G2) should inherit that technology and make a cool next generation aircraft around it. You know Guimbal has been a protégé of Eurocopter in a sense, and adopted a great part of the EC120 technology concepts (rotor head, avionics presentation, fenestron...)


Why EC did let it happen and even fostered it, I assumed they knew it was not attacking the piece of the pie they care about or would care about in the future. They could have strategized in a sense that it was better to have a known quantity fill that market hole.

PANews
28th Nov 2015, 11:37
Best case scenario the engine development will be used in a different aircraft, probably fixed wing.

Yep and they could call that a........ hmmmnnn... let me think now....

A Diamond!

RVDT
28th Nov 2015, 21:59
You know Guimbal has been a protégé of Eurocopter in a sense, and adopted a great part of the EC120 technology concepts

Possibly because Bruno along with AH actually holds the patents for a lot of those technologies?

The G2 prototype first flew 23 years ago!

riff_raff
2nd Dec 2015, 04:57
Again, I bet there will be no Ec120D and no EC120D operators. This is a demonstrator solely built to draw public funds. I can't imagine this going anywhere.Best case scenario the engine development will be used in a different aircraft, probably fixed wing.The HCE recip diesel H120 flight demonstrator was only intended to validate the analytical modeling work done under the CleanSky Green Rotorcraft program within a reasonable cost. If cost were no object, the entire propulsion system could have been retrofit with a more fully optimized design. Regardless, the finished H120 flight demonstrator is still a very nice piece of work.

While a V8 recip turbodiesel engine using machined aluminum heads/block/crankcase, titanium conrods, etc might seem expensive, in reality a production version of this engine would probably still cost 30-40% less than a similar turboshaft. The recip engine would also have far lower operating costs. This was the focus of much of the analysis modeling work performed by Cranfield University under this project. Here is an excellent technical presentation describing their work (the recip diesel configuration is the "HCE class"): http://www.aerodays2015.com/wp-content/uploads/sites/20/1D-Vassilis-Pachidis.pdf

The recip diesel drivetrain makes economic sense for certain applications as described in the paper above. There are no technical hurdles preventing it from becoming a reality. The only issue is the significant financial commitment required to turn it into a marketable product. There are only a couple aircraft OEMs (like AH) that have the massive financial resources required to complete this type of commercial project.

Agile
2nd Dec 2015, 07:50
good presentation, the methodology in there seems to follow like what the airline industry is doing (optimizing flight path for fuel, noise impact...).


if its a sign of things to come, that means no more buzzing the beach at 500ft AGL on a beautiful day. the computer will tell you your finely optimized and most appropriate flight trajectory.


one more point, piston engine have much more torque, than turbines. does that plays any benefit anywhere, for example during training exercise, the instructor can wait a bit more before recovering that sagging RPM that the student mishandled.


is it really that expensive to re engineer the engine part of an aircraft compared to the initial design cost of a program like the EC120.

cattletruck
2nd Dec 2015, 09:51
One good bit of innovation that came out of this is the use of a torsion shaft to drive the main gearbox. Much better than the traditional rubber bands used by other reciprocating engined ships.

riff_raff
4th Dec 2015, 03:47
one more point, piston engine have much more torque, than turbines. does that plays any benefit anywhere, for example during training exercise, the instructor can wait a bit more before recovering that sagging RPM that the student mishandled.Agile- that's a good question.

The Arrius 2F has an output shaft 100% speed of 6000rpm, so at an MCP of 432shp that works out to a torque of 378ft-lb at the MGB input. If we assume the AE440 diesel has a 100% crank speed of 4000rpm, at a similar MCP of 432bhp that works out to a torque of 567ft-lb at the crank. But the diesel engine uses an intermediate gearbox to step the speed up to 6000rpm at the MGB input, so the (mean) shaft torque at this point would essentially be the same as the turboshaft engine.

It's not that the recip diesel has "more torque" than the turboshaft. Instead the big difference between the turboshaft and turbodiesel engines is that the turbodiesel would have far quicker throttle response. The speed of the Arrius 2F gas generator (Ng) is 54,117rpm at 100%, and the rate Ng speed can be changed is limited by combustion stability. So it can take a while for it to spool up from say 85% Ng to 100% Ng in response to increased power demand.

DonQuixote23
4th Dec 2015, 07:27
Riff: Thanks! - the ever ongoing confusion with regards to torque, power and rpm... There are gearboxes, you can always have whatever torque you want :)

Agile
4th Dec 2015, 07:43
Thanks for the precision, at operating speed torque is the same. it is as you mentioned the combustion stability that prevents turbines to provide has much punch as the turbo diesel.


if I am not mistaking former design turbine (like the Turbomeca Artouste) used to be quite stable due to a generous dispensing of fuel,
the new generation(like the Arrius 2F) have been starved in the name of fuel economy thus making their operating position/region very small.


those of you who have flown the 300 (not equipped with governor) might know how responsive the engine is on the up side to recover that RPM, (that is, if not over-pitched yet).


I have heard an Arrius 2F cost $475K to overhaul, that tell me engine cost must be a bit above that number, that leaves a lot of money on the table for that turbo diesel engine.

3top
4th Dec 2015, 16:16
...if you are down to 85% MRrpm and you are NOT in an autorotation and trying to stretch your glide - you are seriously in deep!!

....you are WAY overpitched and no matter the type of powerplant, unless you nearly floor the collective, rpm recovery will NOT be fast, piston or turbine.
[IF you unload the rotor, piston or turbine will recover fast!]

IF you get to 85% under power, it means you asked for more than the powerplant CAN give you, so it is long past (...or actually BELOW) torque levels it can sustain or recover from (without substantially lowering the collective)....

3top:cool:

Agile
6th Dec 2015, 12:59
why is it not possible to have an aviation piston engine that is based on modern technology? :ugh:


an engine that was not designed in 1947 (Lycoming O-540):yuk:
an engine that does not sound like starting a truck (R44):(
an engine that has more than 25KW per liter:ouch:


magnetos!? before coming to aviation I thought only lawnmower used them.


it is really a case where the mainstream solution (ie: turbines) got all the technology focus (dual FADEC and so on ...)


I am not saying turbines are bad, they are ideally fitted for helicopters, but there is a vacuum between the R44 and the H125 that could be filled with a new generation piston engine.


somebody said if we had pursued electric cars 20-30 years ago, they would perfectly adapted now. instead combustion engine cars are perfectly adapted.

riff_raff
8th Dec 2015, 00:40
why is it not possible to have an aviation piston engine that is based on modern technology? :ugh:
an engine that was not designed in 1947 (Lycoming O-540):yuk:
an engine that does not sound like starting a truck (R44):(
an engine that has more than 25KW per liter:ouch:Agile- Unless I misread your post, the AE440 diesel engine seems to be exactly that. In fact, with regards to your KW/L metric the AE440 displaces 4.6L and produces 322KW, which works out to almost 70KW/L.

Heck, the AE440 diesel even uses a pair of single stage centrifugal air compressors, each one coupled to its own single stage radial inflow gas turbine. They just call them turbochargers.:ok: If you listen closely when the engine is operating under load, you can probably still hear some of that "sweet turbine whine".

One other very nice thing about a recip turbodiesel that I do not recall hearing mentioned is that it does not have a susceptibility to damage from debris/dust/sand ingestion that a turbine engine does. Perfect for operating in desert environments.

whoknows idont
8th Dec 2015, 06:07
One other very nice thing about a recip turbodiesel that I do not recall hearing mentioned is that it does not have a susceptibility to damage from debris/dust/sand ingestion that a turbine engine does.

I seriously doubt that. Sand is not healthy for any kind of engine (except maybe silane fuelled engines).

BedakSrewet
8th Dec 2015, 07:17
A ( not so ) new generation engine is the ' Rotary Wankel'. Mazda is presently working on a Diesel version and is determined to -once again - win the 24 hours Le Mans race. Subject engine could be a candidate for helicopters and fixed - wings.

Agile
8th Dec 2015, 07:40
Funny how the back exhaust strongly resemble a turbine exhaust look.
is that for cooling?, surely it could have been made more integrated.


http://www.teos-engineering.com/mbFiles/images/thumbs/800x600/cs-flight-test-high-compression-engine.jpg


could it be the same reason some electric cars still carry a front grill even though the need for cooling has disappeared.


Yes probably both piston engine and turbines have the same susceptibility to dust, however it is much easier to fit air filters on a piston engine than it is on a turbine. Turbine use 75% of the air for cooling if I remember my ground school well. :confused:

riff_raff
11th Dec 2015, 03:07
I seriously doubt that. Sand is not healthy for any kind of engine (except maybe silane fuelled engines).

Yes, intake ingestion of sand is not healthy for either turbine or recip engines. But it is far easier to filter this type of debris from the intake airflow of a recip engine than a turbine engine. Turboshaft helo engines use dynamic particle separator devices on the intake that are far less effective than the barrier filters used by recip engines.

skadi
11th Dec 2015, 05:25
Yes, intake ingestion of sand is not healthy for either turbine or recip engines. But it is far easier to filter this type of debris from the intake airflow of a recip engine than a turbine engine. Turboshaft helo engines use dynamic particle separator devices on the intake that are far less effective than the barrier filters used by recip engines.

Barrier filters are also availble for turbine helicopters. Most of the german EMS-Ships are equipped with these filters from different suppliers:

http://www.helionline.net/060-214274-481806/photogallery///45520.html

http://www.helionline.net/photogallery///45502//2.html

skadi