Engines

[TechMan]

From the array of engines available world wide, and with the avid

 

inventor in all of us, some may like to dare to be different. Wonder

 

when we will see the first diesel powered recreational aircraft here in

 

Aus.

 

http://www.ecofly.de/english.htm

 

Perhaps "Engines" would be a category in itself on here?

 

_

 

Chris

 

 

[Ultralights]

i am waiting for the day someone develops a Automotive diesel

 

powerplant! im still watching the industrial engine market for

 

small Hp engines, up to 80hp mark....

 

automotive diesel is available everywhere!

 

 

[greggf]

... and wherever Avtur is available, it's a lot cheaper than diesel or avgas.

 

 

[Guest TOSGcentral]

I do not know if it is 'recreational' in ultralighting terms (but then I suppose a Lamboughini Diablo is a a recreational car at half a million a pop)

 

bit recently I had a look around a Diamond Star at Watts. Full turbo

 

diesel and a very nice four seat piece of composite engineering!

 

 

[hiperlight]

Zoche in Germany have developed several aero-diesels. An inverted V2 aircooled diesel of 70hp weighing 55kg looks interesting.

 

There are several other companies making diesels for GA aircraft.

 

Bruce

 

 

[Ultralights]

I know this might be a silly question, i drive a diesel van, will Jet

 

A1 go straight into it and run as normal? or is there a difference

 

between JetA1 diesel engines and automotive diesels?

 

 

[hiperlight]

BE VERY CAREFUL!!!! Aircraft diesel engines are designed to run on very low sulphur content avtur (like jet-A1)' but I'm not sure how it is done.

 

Sulphur is a natural lubricant and although auto diesels produced in

 

the last decade or so are designed to run on LOWER sulphur diesel I

 

think jet-A1 might be a bit extreme and cause excessive pump and

 

injector wear.

 

Adding a lubricant like polybutene to the jet-A1 MIGHT overcome the problem.

 

I have read articles about "heroes" running diesel road vehicles on

 

jet-A1 with 5 litres of oil added to 200 litres of fuel with reported

 

success.

 

BUT NOT IN MY DIESEL 4X4 THANKYOU (except in an extreme emergency!)

 

Bruce

 

 

[Ultralights]

dont worry, i dont ever plan on using anything other than brand name

 

diesel in my truck, not even biodiesel, i was just curious as to the

 

difference with all the stories and aircraft poping up with "diesel"

 

engines..

 

 

[Barefootpilot]

My old work used to run a Hilux on 50/50 Jet and diesel used to go just as well as any other Hilux...

 

Had been doing it for over 10K km no obviouse problems.

 

 

[rick-p]

Ok I've read with interest and listened with some concern to the engine bashing given by proponents of the main two engines we use in our magical passtime, cloud dancing. I have been a Rotax (447 and 912) person since Adam was a boy but because of my recent aircraft aquisition I have now also become a Jabiru engine owner and user. What I would like to see in this forum is a genuine and constructive discussion of the said two engines as i do believe that certain of the hype in respect of Jabiru is not now deserved and that the 2200 is nearing a very comparable position to that of the 912. If those of you out there with actual knowledge and experiance could give an unbiased comparison of the two engines I know that it will be greatly appreciated by many. I could imagine that there are many people who seriously ponder on such things but do not ask for fear of appearing a bit dull of mind. Please humour an old fart and give all of us who don't know but want to know the real goods on these engines, who knows evenI maybe able add something not known by others. Lets set asside the street talk and speak of only fact without fiction. If you had heard some of the stories I heard in respect of both engines you would never have either in your pride and joy. WE SHOULD ADDRESS TOPICS SUCH AS RELIABILITY, ECONOMY, VALUE/ PURCHASE PRICEAND MAINTENANCE AND EASE AND COST OF MAINTENANCE just to name a few areas for discusssion. Also these areas could be assessed on a point system of 1 to 10 with 1 being the worst and 10 being the best. It should be a warts and all forum but factual not hearsay, or briefing room gossip. What do you all think? RICK P.

 

 

[Ross]

Hi Rick P

 

From what I have seen of these "discussions" on theRotax & Jabiru engine nobody seems to take any notice of what model motor or what serial number motor they are quoting or talking about. No doubt there have been many changes in both brands and all models. These changes arenot only in their ancillary equipment like undercarriage, cooling ducts, carburettors, propellors, starter motors, alternators, oil pumps, radiators but the actual engine design of parts like pistons, valves and seats, fins on cylinder barells, head design as well and it's service requirements and service frequency.

 

There have beenmany changes to both brands of motors and their respective models and probably many of these are unpublished. So remarks by consumers about an engine are about that particular engine and often cannot be generally applied to describe the current models. The changes do not all occur at one particular engine number but are generally a continous process over the life of the engine model.

 

AJabiru 2200cc enginecame withmy J160 kit before the J160 plane was certified.The fuselage was number 14 in the J160 series. In this engineor its equipment or its service requirements are quite different from the "same" engine manufactured two weeks earlier and different again from one manufacturedsome weeks later. I would want to know the brand, model number and serial number of the engine when any detail is quoted because the information is quite meaningless without that information.

 

Regards Ross

 

 

[rick-p]

Yes Ross point taken. This is more probably the case for Jabiru engines as they are evolving at very fast pace. My idear was basically to establish a factual base as to the pro's and con's in respect of each engine. Maybe the do's and don'ts also that would assist those who are in the dark and at times have only the club house or pub conjecture to base their decision on. It's no good going to the factory to ask what a manufacturer thinks of his product. The good or the bad oil must come from the end user not the opposition. You need like a hole in the head a Rotax 912 user making observations in respect of a Jab 2200. Do I make sense or have I confused the issue further. I hear every other day Rotax proponents bagging Jabiru but nearly all have never owned or used a Jabiru engine and at times there is the reverse of this situation with Jabiru motor owners. Can someone who can see where I'm coming from help me out here please? RICK P.

 

 

[BigPete]

When I picked up my J160c from Bundaberg in Feb of this year, I was given a tour of the engine manufacturing plant.

 

The quality and care of making these motors is unreal. Each part is weighed and measured. Each part - not every tenth or one hundred or so.

 

It is hand assembled and then dyno tested. I believe the same process is used in the V8 Supercars - they call it "Blueprinting" and a V8 Supercar motor has a value of around 100,000 dollars.

 

From memory I think the 2200 motor is around 12,000 dollars!

 

One of my friends has a Zodiac with a 80hp Rotax. Its a great little areoplane. Great little motor - he loves it.

 

regards

 

 

[Guest micgrace]

Hi

 

Just to clarify. Hand assembly is not the same as blueprinting. Blueprinting is returning all components to exactly factory specifications this goes down to exact port matching, combustion chamber bowl matching, Precise balancing of rotating components to each other, canshaft degreeing etc

 

Standard practice is to assemble components to a+ or - tolerence, not to exact , original designer specs (blueprints). Components outside spec are discarded. There will be some variability, but within defined tolerences.

 

The final dyno test will do a few things. Weed out engines that don't meet power specs. Pre run in, oil leaks and other mechanical problems. A very good idea.

 

As for which is better, Jabiru or Rotax, the design concepts are so far apart, they can't really be compared.

 

It comes down to if you want direct drive or not. Both reduction and direct drive have advantages the other does not.

 

My 2cents worth, Micgrace

 

 

[facthunter]

The efficiency of a diesel verses petrol can only be related when you are comparing apples with apples. Honest dyno figures should not be too difficult to obtain The specific fuel consumption Lbs/hp: hr or like figures are needed obtained under similar conditions. Generally the diesel will be about 50% more efficient due to the higher compression ratios that can be utilised, but some petrol engines may be closing the gap. The high operating pressures in the diesels require stronger & generally heavier components which increase weight, reduce achievable safe RPM's(dynamic loading) and produce fatigue in components Better design & materials obviate these problems but ensure that the powerplant will be more expensive. Diesel engines in aircraft are not new, the Junkers (jumo(? double crankshaft,2 pistons in each cylinder ( 2 stroke) was used in bombers an east european firm produced 9 cyl radial diesel called a ZOD. and the american car Co, Packard, produced a radial diesel about 1934 which established an endurance world record. N....

 

 

[Guest micgrace]

Hi Neville.

 

Actually I think diesils are closing the gap with petrol, power output per litre that is. Common rail injection (the biggest advance). Higher spec materials, higher speed engines.

 

It is theoretically possible to build a high efficiency (hp per lb fuel) petrol engine using a stratified charge principle. How this works best is one set of injectors "fires" an ultrarich mixture into a cavity in the piston. The sparkplug is extended into the region as well. Another injector "fires" an ultralean mixture into the combustion chamber proper.

 

The sparkplug is then fired in the ultrarich area, igniting it, the flamefront then progresses into the lean mix and fires it off.

 

Combine variable cam timing and lift control (still experimental) and little touches like sodium filled vavles and you have avery flexible engine. Of course, it's now very complex, expensive to manufacture and service.

 

This engine theory wasput to actual use by Honda in the 1970's They used 2 different carbies to do the stratified charge. But was discarded after some consumer testing in the USA.

 

Horsepower went up and fuel consumption went down. (halved)

 

Just some thoughtsMicgrace

 

 

[facthunter]

We dont need complexity in our neck of the woods for the sake of reliability & our ability to service & maintain. Cost also. Keeping an eye on the eurodieselsat the small end of the auto market might produce some thing,.There were some small aero diesels in the EAA yearbook, they were listed as radials, but the small one looked like a V twin. Does anyone have more on them? I think they were German. Vibration is a big consideration I feel as its doing damage all the time. Ive done about 10 Hrs behind a HKS.700 Twin pretty smooth as far as balance is concerned Ive been advised that the main jets have to be opened up (high EGT's) This one did. It also runs a very high compression ratio so needs good fuel. N...

 

 

[Wilfred]

Diamond use diesels in their twin very successfully

 

http://www.galvinflying.com/GalvinFlying.aspx/Aircraft%20Sales/New%20Diamond%20Aircraft/Diamond%20DA42%20Twin%20Star

 

http://dieselair.com/2005/09/thielert-world-leader-in-aero-diesels.html

 

Thielert Centurion 1.7 (formerly TAE-125) turbo diesel four cylinder engines, which are designed to run on either diesel or Jet-A1/jet fuel. Germany based Thielert's Centurion turbo diesel engine was certificated in early 2002 and is based on a Mercedes-Benz automotive design. Diamond expects the DA-42's two engines will burn just 45 litres an hour while cruising at a very fast 333km/h (180kt). Standard fuel capacity is 200 litres, while optional long range tanks take maximum fuel capacity to 280 litres.

 

The engines drive slow turning three blade constant speed propellers, which combined with the engines' low noise emissions and the DA-42's fast climb rate will result in a low ground noise signature. The engines also feature electronic fuel management, automatic prop controls and auto feather.

 

 

[Guest pelorus32]

It seems to me that the issue with diesel engines from an ultralight aircraft perspective is weight.

 

As an example the Rotax 912 ULS 100hp quotes a weight of 57kg engine only. The Wilksch WAM-100 - also 100hp has an engine only weight of 99kg. The Wilksch weighs 174% of the weight of the Rotax. Put another way at 544kg MTOW you have just lost 7.7% of your MTOW for an engine of similar power. (As an aside 99kg must me a magic number as several of the diesels of similar power quote that weight).

 

On the other hand the Wilksch uses 11.44kg fuel per hour at economy cruise compared to the Rotax 12.78kg this is for both engines at 44kw power output.

 

So lets assume a 4.5 hour endurance and slightly innacurately assume the whole 4.5 hours at 44kw. For the Rotax we need to carry 57.5kg of fuel and for the Wilksch 51.5kg of fuel.

 

The net result: I could carry 36kg more usable load with the Rotax than the Wilksch on my 4.5 hour flight.

 

I think that the numbers are pretty right - I never was great shakes on my 'rithmetic.

 

Regards

 

Mike

 

 

[Guest secatur]

Hi, As a new builder (Zenair CH-701) I must agree totally with RickP .

 

The choice of engines appears mind-boggling, and it appears that choice is generally made on "gut-feeling", or "holden vs ford" mindset.

 

Is it more that so few of the newer engines (Ecofly seems to have great specs !) are available or serviced here in Australia? There does also appear to be a sizeable number of GA/RA deisel engines available, why none in Australia yet? It would be great to get one of the more experienced members of this forum to actually explain/justify his engine choice..ie:why that one? We're not checking up or questioning your decision..just would be very helpful to know how and why people arrive at these decisions.

 

 

[rick-p]

Hi Secatur, my point exactly, thanks.

 

Rick P.

 

 

[facthunter]

Why aren't Hirth engines popular in australia? They have been building engines for a long time, even larger 4 strokes. They are very popular in europe (I believe) They have got nikasil (or equivalent) cylinder treatment which is better than cast-in cast iron sleeves. N... Anyhow as I've said elsewhere in these forums, I reckon a good liquid cooled rotary (not the gnome&rhone) could be worth a look. N

 

 

[Guest P.A.]

Subaru are developing a flat 4 Diesel.

 

 

[Galpin]

I wasn't aware Subaru were devoloping a diesel. Can you provide a reliable web site with information.

 

Thanks

 

 

[Guest P.A.]

I had a look yesterday but couldn't find any info on line. I have been

 

a member of the Subi club for 24 years and that is where I heard about

 

the engine, maybe??