# Diesel-Hybrid Helicopter Concept Showcased in Berlin



## EVDL Archive (Jul 26, 2007)

Aircraft would utilize twin, two-stroke diesel engines powering electric generators.

More...


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## Sunking (Aug 10, 2009)

Now there is a waste of efficiency. Diesel can be used as AV fuel. and the Cessna 172 TD uses diesel


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## david85 (Nov 12, 2007)

Vaporward alarm just went off.....my head is still ringing.

And yeah, complete waste of time to make a hybrid aircraft. Clearly a concept cooked up by a green proponent that doesn't understand the laws of physics.


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## aeroscott (Jan 5, 2008)

The highbred aircraft is a workable concept . First aircraft need extra power for takeoff , then if the engine fails and you have high power batteries ( Headways or something ) you can get back on the ground with battery power . It is very hard on aero engines doing take offs at 150 -200% of cruse power . Then as batteries get better , no more engine . Some Japanese company announced about 6 months ago that they were going to introduce a battery with extremely high power density . If so a Moler stile air car could work . These type vertical take off and landing aircraft take huge power for VTOL but normal power for level flight . I think Mr. Moler's other major problem is the very high speed control to keep in balance , ic engines must react much slower then ac motors / inverters can .


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## david85 (Nov 12, 2007)

You're forgetting the added weight of using a hybrid system in an aircraft. Engine thermal efficiency does matter, but adding weight to an aircraft matters much more than on a car. If they ever do successfully fly one of these things, I would expect the fuel economy numbers to barely match a similarly sized conventional aircraft.

Better off just making a lighter, more powerful engine, in a lightweight carbon fiber airframe. I suspect they will have to come up with something like that anyway just to get this idea off the ground.

And I stand by my vaporware comment.


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## aeroscott (Jan 5, 2008)

the more then 20 people that I knew that all died in take off crashes or cab icing crashes would have loved a few kw to make a safe landing . If fuel mileage is not increased ok , but as the batteries get better less fuel . For max speed and range today ic engines win with less options when something goes wrong . The same was said for rocket parachutes on ultra lights and light air craft .


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## david85 (Nov 12, 2007)

According to them, the concept is for the sake of making a more green helicopter (efficency and noise), no mention of added safety. Hard to say if this idea can actually deliver reasonable power on battery alone from the limited description they offer. I don't claim to be an expert on aviation propulsion systems but from what I have seen and read on the subject, an engine failure is only one part of the system that can bring the craft down. Weather you power the machine via, pistons, turbines or an electric rotor, they all still have to go through a fairly complex transmission with hundreds of things to go wrong between the engine/motor shaft and the rotors.

Mounting a chute on a light plane is not the same as adding a hybrid system in my view (much more space, weight and complexity = more things to go wrong), and thats not what they are talking about anyway.


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## aeroscott (Jan 5, 2008)

carbon fiber is common in high end home built kits , some cruse over 300 mph . I picked one end of a fuselage half with one hand and this was a large 4 place turbo prop 600+ hp , 100k for the kit finished 500k or more . try buying fuel @30 gph for 1000 hrs. still no worse then 10 mpg . But a lot of pollution/money / hr. With 4 times better batteries , maybe less range but the same performance and green .


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## david85 (Nov 12, 2007)

Love the idea of building out of carbon fiber. Some day I'd like to make a car like that. High speed, Low drag

For that matter, I like the idea of making anything out of it, weather its hybrid/electric or not. Doesn't fatigue, lighter than aluminum, stronger than steel, and can be cast in any shape and structure limited only by your own imagination.

Ah, some day.....

300 MPH kits. You're talking air planes or helicopter? Haven't seen home built choppers that can go that fast.


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## aeroscott (Jan 5, 2008)

fixed wing


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## TX_Dj (Jul 25, 2008)

david85 said:


> High speed, Low drag


I'm a big Command and Conquer fan. Every time I see these two together, it reminds me of one of the unit-activation sounds in one of the C&C games, he says "High Speed, Low Drag!" 

For climb, hybrid would be of benefit, meaning less energy required from the engine(s) to climb at the standard rate, and climb is the biggest fuel consumption. It wouldn't do a dang thing for cruise. It's questionable what effect it would have in descent.

There's a company that makes electric trikes and electric motorgliders (based on the Moni) in which the regen braking concept is used well. During descent, the system allows the prop to mostly free-wheel in the airstream like a windmill, capturing some amount of the stored energy of altitude back to the battery. This helps buy you a little more wiggle room in the final approach and landing, because you will tend to land with as much if not more energy in the pack than when you began the descent.


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## Sunking (Aug 10, 2009)

Well as I said earlier the concept is pretty much a waste of time and money. For the same reasons deisel did not catch on in the 20's and 30S still pretty much apply today.

Diesel has a couple of advantages mainly in slightly higher energy density content, but it disadvantages far outweigh and gains in its advantages. The two most important in aircraft are power to weight ratios of the diesel engine compared to a turboprop or jet engine, and cold temperature characteristics of diesel fuel. Nothing ruins your day more than having your fuel turn to Jello at 20,000 feet.

The resurgence of diesel engines used in aircraft is due to the extremely high cost of AV fuel which is mainly due to artificial inflation from taxes, and only one refiner of the product. But the same problems still hinder diesel as an aircraft fuel. To date the only aircraft I know of approved for flight with a diesel piston engine is the Cessna 172 TD.

As for the helicopter I fail to see any advantage using diesel engines to turn a generator to power an electric engine. The conversion losses are huge, not too mention all the added weight. I understand two engines as this is common in rotary wing aircraft for redundancy, but twin turbine engines would be much lighter, producing more power with much higher reliability. There is no need for a generator and electric motor, it just waste energy and adds unnecessary weight.


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## david85 (Nov 12, 2007)

TX_Dj said:


> I'm a big Command and Conquer fan. Every time I see these two together, it reminds me of one of the unit-activation sounds in one of the C&C games, he says "High Speed, Low Drag!"


gave myself away there, didn't I?

I actually started playing C&C when it first came out in the mid 90s. I have everything up to generals. Tried the C&C3 demo and didn't like it so I play supcom/FA instead but still have older copies of the classic C&C series. RA1 is still among my favorite.

I think that particular phase was a movement command confirmation for the allied tanks in RA2/YR?

Used to spend hours on end modding Tiberian Sun and Red Alert2. More time than actually playing come to think of it. Haha, I guess I just can never be satisfied with things as they are.


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## david85 (Nov 12, 2007)

Sunking said:


> Well as I said earlier the concept is pretty much a waste of time and money. For the same reasons deisel did not catch on in the 20's and 30S still pretty much apply today.
> 
> Diesel has a couple of advantages mainly in slightly higher energy density content, but it disadvantages far outweigh and gains in its advantages. The two most important in aircraft are power to weight ratios of the diesel engine compared to a turboprop or jet engine, and cold temperature characteristics of diesel fuel. Nothing ruins your day more than having your fuel turn to Jello at 20,000 feet.
> 
> ...


I agree power to weight ratio and conversion efficiency losses are the flaw with the concept. However I still smell a heavy odor of vapor in the air over this one. pun intended.


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## Sunking (Aug 10, 2009)

Well there is a way to use diesel fuel in an aircraft. Just build a turbine engine or jet to burn diesel. I mean heck you can use diesel in a turbine or jet engine in a pinch. 

Jet A, Jet A-1, and JP8 are number 1 diesel (kerosene) with additives like an anti-freeze agent.


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## david85 (Nov 12, 2007)

Sunking said:


> Well there is a way to use diesel fuel in an aircraft. Just build a turbine engine or jet to burn diesel. I mean heck you can use diesel in a turbine or jet engine in a pinch.
> 
> Jet A, Jet A-1, and JP8 are number 1 diesel (kerosene) with additives like an anti-freeze agent.


Well, yes that I knew. My vaporware remark was with regards to the rather poor CGI of the hybrid chopper which evedently hasn't been built yet.


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## TX_Dj (Jul 25, 2008)

david85 said:


> I think that particular phase was a movement command confirmation for the allied tanks in RA2/YR?


Definitely RA2. I've probably played more RA2 than any other. I've skipped quite a few of them, but I'm on C&C4 now, Tiberian Twilight. It's *vastly* different than any other I've played, and it has some real challenges to it.


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## gyronut (Feb 7, 2009)

Sunking said:


> Nothing ruins your day more than having your fuel turn to Jello at 20,000 feet.


Stop writing about something you have no clue about.
All diesel aircraft fly on JetA.
And I don't think anybody had ever complained, even at 40.000 feet 
about any "jellp"...



> To date the only aircraft I know of approved for flight with a diesel piston engine is the Cessna 172 TD.


Rubbish again.
Dimond D-40, Dimond TwinStar D-42, Cesna 182, Piper 28, Robin, just to name a few...



> As for the helicopter I fail to see any advantage using diesel engines to turn a generator to power an electric engine. The conversion losses are huge, not too mention all the added weight. I understand two engines as this is common in rotary wing aircraft for redundancy, but twin turbine engines would be much lighter, producing more power with much higher reliability. There is no need for a generator and electric motor, it just waste energy and adds unnecessary weight.


Again no clue.

The most critical part on a helicopter, besides the engine, is the transmission.
From the engine to the main rotor and 
from the engine to the tail rotor.
On top of it you have a very long shaft to the tail rotor.
Transmission failure is much more critical than engine failure,
after which you can autorotate to the ground.
With jammed or broken transmission you are toast.

So eliminating these critical elements and replacing them with some
redundant cables and electronics, with redundant power source
from multiple generators and batteries makes really sense.

At least to me.


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## Sunking (Aug 10, 2009)

gyronut said:


> Stop writing about something you have no clue about.
> All diesel aircraft fly on JetA.
> And I don't think anybody had ever complained, even at 40.000 feet
> about any "jellp"...


Jet A is diesel #1 kerosene, not diesel #2 oil



gyronut said:


> Rubbish again.
> Dimond D-40, Dimond TwinStar D-42, Cesna 182, Piper 28, Robin, just to name a few...
> 
> Again no clue.


You have a hard time reading. I said the only diesel I know of, the Cessna 172 TD. Try learning how to spell Cessna


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