Jethro Belle

Thanks for biting @Old Koreelah My academic theorizing ain't worth squat without backing from actual experience Seeing Theilert ( Thielert Centurion ) seemed to have had significant problems, I was wondering how some-one in NZ can bolt in a pretty stock Peugeot (manual diesel injection swapped in I believe) and happily and safely 'go flying'. Do you have links or references to start researching this install? I must haven't searched right. How many are you are flying these things? Is it a Jodel thing? What are your conclusion based on experience. Do you recommend it? More info please. I note continental are building on their Theilert buy-in Continental expands Diesel Engine Range - Australian Flying (The Chinese are coming!) At a fraction of 10000 hr TBO estimate, most safety cost minded fliers will be interested:taz: PS: My comment about the Pug reliability was just to get your bite

I share your passion/dream for Diesel I put that in the realm of the possible/inevitable, even if it is a turbo. The Wankel is a seductive design, but it killed NSU then Mazda struggled with it. Always the same reliability limits imposed by physics: seals and thermal loading on the combustion side. I hate to imagine the tribology of the seals screaming through the combustion sector with the lubricant film breaking down due to the wall temperatures (I think @facthunter Nev, keeps warning about most auto-engines not being designed for constant full power output). The elongated combustion chamber on top of the sealing makes limits combustion and high thermal efficiency (most prefer a throbbing V8 with low down mumbo in a big car over a screaming rotary if you get the same fuel consumption. Yes I have rotary friends and understand their thrill of beating V8s. As a Wankel expert you know all this of course. As an Engineer (or was it Scottie) I know 'ya canna break the laws of physics captain'. I never say absolute never to anything, but unless some new technology is developed that changes those fundamentals, development will not change anything much. If you are chasing diesel then the Wankel with its struggle to keep sealing low compression SI seems the wrong choice (I briefly investigated the idea myself long ago). The humble old, inexpensive, easy to fit, circular piston ring is hard to better for sealing. That is the chief reason we are stuck with the problems of pistons and cranks (achieving a good seal for elongated service proved relatively easy) (IMHO). Wishful thinking about avoiding high accelerations stresses and vibrations ... does not change the reality that without a new technology to seal non-circular shapes, it will not be competitive. I would never have predicted that. It acts as lubricant/wear coating on exhaust valve seats. Perhaps the high rotor/seal temperatures convert it to an abrasive oxide. Exhaust valves are pretty hot!!! NSU owners used to salute each other as they passed on the autobahn. The number of fingers they held up indicated how many Wankels they had replaced Not sure if RX owners continued that tradition

My reading is that ash-forming additives may foul the spark plugs on aeroplane engines "designed to some burn oil" (I think that is quoting Lycoming). Lycomtinentals run with high piston clearance to avoid seizing because air-cooled heads get hot at full power. I can't see how it closes up the clearance myself, unless the pistons run hotter in an air-cooled engine. Can anyone provide insight? Zinc additives seem to be the main problem, but I understand Zn has been almost eliminated (many think the new high spec oils are not so good because of this) in the new spec oils for catalytic convertor life.

Can you offer more insight into the Gemini. With modern fuel injection is could work if they can get the power from both cranks combined reliably. They are cleverly combining them as part of the redrive (one component doing two functions to save weight and complexity). If it is the 27th owner it looks more like going the way of the Jumo ! Is it Myth or will it be legendary? The reason I mentioned the Gemini is that it is diesel is that is not quite attempting what is already been successfully covered. I am acutely aware of the weight limitation current diesels impose, and that Jumo stopped production (in a low cost fuel environment), and that most aero-engines bankrupt their creators. Most thread readers may know about Charlie Kenny’s Peugeot turbo diesel Jodel . I haven't read about it in detail, except he seems pretty chuffed with it. My response was I hope their engines don't suffer the bugs their cars seem to I would prefer to fly diesel for safety reasons.

Hi Marty. I am glad if that is now the case (I suspect RA more than GA). I was responding to @Yenn post #73 and it seems the at least some Mooney models (@facthunter post #86) have wet wings also. Didn't the F111 have wet wings and the sealants allegedly cause all sorts of cancers in the applicators required to crawl into the tanks to reseal them? Also the Concorde was forced to retro-fit bladders after the flight 4590 crash (Yes: I know that is JetA1 before anyone posts. Yes I know RA/GA are not supersonic before anyone post. The point is that sealing wet tanks against corrosion and leaks is a risk IMHO).

Isn't it Mooney that have a bad reputation for wing corrosion, that requires regular inspections? Magnesium in contact with Aluminium is a galvanic cell waiting to happen, so the sealing needs to be better, over many years, than any I know of. Any movement tends to break sealant as it embrittles. Certainly extra concern for any Mooney owners using pump-gas. Any Mooney owners have the facts?

I suspect the Lycoming Unleaded Fuel pages included in the above post explain how. Lycoming are correctly worried about pump-gas because it is not controlled enough.They define Mogas according to the standard petrol standard plus a few additional controls (tests that the mogas meets a defined level such as vapour pressure). The have certified some of their motors to run on their defined Mogas (I suspect these engines have valve seat inserts). They haven't promoted it widely in case owners rush down the petrol station and start filling with pump-gas. There are some risks with using pump-gas, but like all risk I would guess 95% (wildly speculative) of users will never experience any. I note Auto Fuel STC News | Airplane Fuel News confirms what I stated above about lead. I remember 'nice' grey spark-plugs meant good running With the exception of vapour pressure and reduced calorific value of alcohol, I cannot see why engines and fuel systems designed for mogas (not old aircraft designed for 100LL) would have any problems. I understand the use of pump-gas is widespread within the RAA fleet. Maybe dragging some incident reports may reveal if reduced engine power or vapour locks are an issue. Caveat: Anyone using mogas in their aircraft must make their own risk assessment as my comments are poorly informed opinions of a non-expert.

Thank-you Yenn, I will add aluminium corrosion to my list of fuel issues. Rivets contain cold work stresses making them more corrosion prone (sets up a corrosion cell with the large area of adjacent sheet cathode. Being a small anode results in concentrated rapid corrosion . Extra justification for non-rupturing tank bladders, yes?. I should have included the link with my post = Lycoming - Knowledge Base starting at Unleaded Fuels Part 1 and going to part-4 I don't think their concerns cover your corrosion issue. It could be the alcohols content. I know pump-gas can be 'tainted' with cheaper substitutes like the toluene scandal a while back. I imagine some suppliers may not control sulphur very well or someone along the supply chain blends cheaper high sulphur stock. Contents also depend on where the base crude comes from (as evident from the different smells some fuels give, which is from the aromatic content). The bottom line is that quality control for aircraft use is not there. The fuel may be identical in 95% of cases, but you have no legislated assurance, so that unknown 5% is the risk. Even the 10% would probably be undetectable from running your engine on the ground. For engines not designed for poor fuels Lycoming is correct. It is not about immediate engine failure or problems running. Vapour locks in the fuel system are an obvious risk. Low engine power on climb and running out of fuel because uncontrolled high alcohol has reduced the specific energy seem to be the most likely immediate risks you take (IMHO). Also running unleaded in an engine designed for leaded will increase valve-seat recession (all vintage car owners know that). For the low compression Lycomtinentals it was never about high octane. Low compression ratios equal low engine stresses at the expense of fuel economy.

Its back Gemini :: Aviation Gemini :: Gemini 125 What do you reckon to that Nev.

That is a bold claim! Lycoming have approved mo-gas for some of their engines but have some justifiable reasons why using pump-gas, as they define petrol direct from the service station, as being non-approvable (recently read it on their web site). I am not a big fan of Lycons, but I would be proud of the safety legacy they have built. New is not automatically better As I understand it the unleaded trial AVgas 82 UL was running as a two grade system that never gained traction, so the original 100LL is continuing. Did I miss something?

That is what scares the bejeezus out of me with home build, and even some factory builds. Static G wing loads tests don't come close. I wouldn't want to be the 'test-pilot' testing Vne on such aircraft and is a major reason I would not design my own, unless there was significant reasons to do so. Impossible to build an infinitely stiff wing, and several circumstances can cause flutter. How strong the wing you test is does not necessarily mean all builds will be identical, unless you have very tight build control. A good time to have a BRS, so long as it doesn't go with the wing, or get twisted in the spiral dive. 150 knots is around the Vne of the Sonerai which was what a starting point for me, and still have not rulled out. You can upgrade it to 185 knots Vne which is safely higher than I would ever expect to reach in worst circumstances for my non-aerobatic flying.

It was a blanket claim, so I provided examples that will take a lot of beating Yes it is unfortunate Lycons don't, but that is the diesel engine thread. Not so much a failure as the laws of physics as engineers have managed to apply them so far, while constrained by lawyers and accountants.

Yes, it does seem counter-intuitive . Same goes for retractable undercarriage. I have concluded that if the basic aircraft is a drag bucket (and most older GA I place in that category from an engineering/fluid dynamic perspective) the removal of struts and undercarriage has less effect than linear thinking hopes. Power required goes up with velocity cubed, so reducing overall drag 10% will shift cruise speed upwards only 2.15% max, but the increased weight means it is less than that. Birds fly without crutches and their gear up, so we are not designing aeroplanes that clean yet. The trick is to start with slippery fuselage and low drag wings, or not bother. Slippery aircraft also mean less fuel burn. Slippery aircraft should IMHO have airbrakes/spoilers fitted like gliders. More complexity and pilot skill required, but so much extra control on landing. You could fly much higher approaches and not float/overrun. (All IMHO and expect correction if pilots of both glides and GA can shed light) I am sure everyone here knows it already.

About the same time they can work out how to close down all coal and nuclear fired power stations, do you think? When do you predict Lithium battery energy density and safety will match JetA1? How will Nev cope without the incessant drone of a Lycomtinental All fun. Don't take anything asked seriously.

Yes, I remember the Cessna Cutlass (It has wing struts too ). Describes the arrangement well. First time I saw it (about 10 years old) I thought the undercarriage was falling off. I agree it is a clever design (but manufacturing quality and details seem to have caused their bad reputation, not the basic design). Service reports backed reasons are give in Cessna 172RG Cutlass RG - AVweb Features Article . Nothing that could not have been rectified, but any complex mechanical system has more modes of failure, including ability to land 'gear up'. The only 'designed in' problems I can see are that failure to lock in place will end up with wheels pulling back and collapsing, and the rearward weight-shift. I have two very young children, so a 'family bus' is one option, but avoiding risk to children is why my plans are long term and for very low risk compared to other posters. I need to stay alive long past my "use by" date for their sake. I would like a 'fast' plane and observe birds fly with their gear up, but realize the higher landing speeds and difficulty that come with it, especially transiting from a drag bucket (also lower crash survivability, not bush landing ...) I read about the Duchess while researching engine out characteristics. It was highly regarded as a 'safe' twin to suffer an engine failure. Very nice, but above my resources. Definitely a hire or share aircraft

The Rotax 4 strokes are high revving (hence my continued statements similar to yours). My understanding was the Porsche Flugmotoren was complex and expensive (a reduction drive was not viewed well in GA back then), not that the high rpm wore out their cylinders. Early pilots reports were similar to those received from Rotax owners (smooth refined engine). There were so few built I doubt crash statistics or TBOs achieved prove much. I haven't checked them. Anybody have the data? Mr Wikipedia confirms my understanding that it was not commercially viable for Porsche to provide such a small number of engines (which ended up not being a modified 911 motor) in the Litigious USA market (From memory Porsche was in serious financial trouble because of it). Bugatti In crash statistics I saw for experimental engines the internals of auto-derivatives were less accident causing than Lycomtinentals. That was the only statistic they were better. I suspect electronics and peripheral malfunctions, more than the core engine, were problems for Porsche also. I agree in general with what you are saying, but high revving does not automatically equal unreliable. It has to be better engineered to deal with higher stresses, wear and heat. Engines run at high revs run into thermal induced failures if they are not designed to cope with the significant heat load as a steady state operating condition. Overheating the cylinders and rings will cause major wear due to lubricant film breakdown. The exhaust valve guide is usually high wear in heavily loaded engines not designed for it. I think we agree:scratching head: Perhaps your post was a general warning to readers. My issue is you appear to be damning all high revving aero-engines outright, no-exceptions.

I will not attempt a Bass Straight crossing until considering myself past probationary pilot status, in any aircraft. From my previous post that will need at least 250 hrs under my belt to have 'improving' judgement. This thread convinced me a few pages back: now I am just picking up pearls of wisdom and theory. Being from an Engineering background I am interested in the C210 in its own right. My dream was never about flying that type of aeroplane, but the same phsysics apply. .

While looking up where I can get "The Killing Zone" I encountered comments questioning the statistics quoted (eg: [MEDIA=reddit]flying/comments/3eni9i[/MEDIA]) The FAA was prompted to publish 'correct' statistics https://www.faa.gov/data_research/research/med_humanfacs/oamtechreports/2010s/media/201503.pdf . Interesting reading, with the peak annualized non-IR GA accident rates peaking at 250 TFH and 823 TFH for IR. I always imagined it would drop off sort of linearly after the first few hours of going solo. Shows the importance of mission difficulty and misplaced confidence in determining outcomes.

Some great fire risk mitigation posts followed your initiator post. I have been trying to find some statistics of GA about the relative risk or being killed by a fire while flying, a crash impact, a post crash fire. Do you know any papers or links that save me dragging through crash statistics? The level of risk will determine how much effort and additional weight each risk justifies. I have flown in a Jabiru (I was passenger) with a lightly restrained extra Jerry-can of fuel in the back to a field with no refueling capacity (sort of thing that happens regularly I would imagine). At the time I wasn't concerned too much (wasn't my responsibility), but now I would be. A free flying Jerry can to the back of the head, is probably a similar risk to a header tank splitting above the engine, or some other 'exposed' locations that long range tanks are fitted. Being broken up on crashing is one thing, being subsequently burned alive reaches a new fear level. Just musing about risks we ignore at the time because we are 'relaxed' that in hindsight were risky. Is there an RAA SOP for carrying extra fuel (not in the aircraft fuel tanks)? This site provides relevant discussion Is it legal to carry extra Avgas in a jerry can? - PPRuNe Forums and this one has good SOPs type advice Jerry cans in aircraft - Page 2 - FLYER Forums particularly static electricity. I note mention of fuel cells in the MOGAS or AVGAS - remote area refueling options thread and lots of options in the Spill Resistant Refueling ?? thread, but could not find anything in the Tutorials. Does anyone run puncture resistant fuel bladders? Do they cause any problems, other than slightly reduced fuel capacity and increased dead-weight? corrosion of contacting aluminium due to trapped moisture perhaps?

Thanks @bexrbetter for your confirmation. Dafydd seemed to be distinguishing the crash cocoon surrounding the pilot from the rest of the fuselage spaceframe and I was questioning if making this part 'infinitely rigid' wasn't overkill and excess weight (seemed to be what he thought he was doing in his build). If this is was what Dafydd was saying then the cocoon would not absorb energy (and not intrude on the pilot), instead it would tranfer the force remaining after fuselage crumpling to the pilot harness/seat. Yes I know there is no such thing as 'infinitely rigid': just keeping it simple. Maybe so rigid you die first is the correct phrase . Based on your big hits, did the members bend in or out? Did they protrude into the pilot? What is your opinion about how a Jabiru would handle the same 'big hits'? Fibreglass is pretty amazing in failure. If well made it absorbs far more energy than you expect, not just by massive elastic deflection, but by fibres progressively failing. Clever FRP design can achieve significant energy absorption (I recall flywheel energy storage used carbon fibre that was designed upon failure to absorb energy by becoming 'fairy floss' and avoiding large chuncks taking off your head.). CrMo structure appeals to me because the design does not require Laminate FEA and it provides rigid strong tough points of knowable behaviour to anchor things like the harness, seat etc. Although it is considered old tech by some, for one off home-design/build (where quality achieve and control is hard) it is hard to beat for safety (Also when buying an aircraft someone else has built). You can design it to fold up in certain ways, as many have posted, which is where crash survivable design lies IMHO. Well designed (extensive CAE) and developed (A crash testing program) FRP will win out for factory builds IMHO (Actually what has happened and what Oscar said). . Yes I saw the fatality stats and they are very low! Amazing and a big plus for Jabiru. I wonder if the energy absorbed wrenching off the front firewall is greater than if they made it stronger so it didn't break free Yes this is the common theme in structural materials. In the pursuit of weight saving the strength is increased, but ductility suffers and with it toughness (energy absorption). Plus with thinner sections bucking is more problematic. In the case of FRP especially CFRP it tends to be load oriented lay-ups that give incredible strength, but as soon as that is exceeded: NOTHING. That means massive loads on the occupant and then fracture with 'no' energy absorbed (the area under the elastic deflection curve of CFRP is negligible because its elastic modulus {for low resin layup beyond the ability of most home-builders} is so high, unlike glass fibre). The other problem with oriented lay-ups is they fracture at minor loads parallel to the main fibre orientation when non-design oriented loads are applied (what happens in crashes). Of course very knowledgeable fibre reinforced polymer experts with big budgets and computational grunt (like F1) can design 'toughness' and crash loads into the structure. Hopefully FRP aircraft builders are up there with F1. My exposure to naval architecture indicates early CFRP yacht designers didn't appreciate, or even consider, what happened when you hit a submerged object: Result = multi-million dollar embarrassment dragged to the bottom in a few seconds by the tonnes of lead in the keel I understood a weld stress relief was undertaken to relax weld stresses. What do you mean by a full heat treatment? Quench and temper?:yikes:I was a little surprised about the temper condition variability CrMo suppliers in Australia quote online as aircraft grade. Made me wonder a bit about what home-builders were buying and how they were subsequently heat treating. Must research this more. Thank-you for the update Nev. I suspect he was giving more than he got, so gave up and is posting elsewhere. Shame, but his posts are still great guidance for people like me.

Yes it is interesting how USA is very attached to their carburetors so it is worth understanding. It places them way behind in the power game because the venturi restricts airflow and looses several percentage horsepower. Poor mixture distribution leads to more power derating, such that changing from carburetor to MPFI gives 10 to 20% power increase (on car engines)! They aren't stupid however. By restricting the air intake the engine remains more lightly loaded. Those old enough to know the anemic power than the VW air-cooled boxer (the beetle and Kombi engine) could reputably be pushed along at full throttle for hours because it was impossible to get enough air in and exhaust gasses out to overload it (This wasn't my experience of Flubdubs, which I why I am wary of high power VW aeroderivatives). Hopefully some VW aeroengine cognoscenti will post clarification on this. Anyhow I suspect upping the power output on an Lycomtinental without other "improvements" may be at the expense of TBO and reliability (it applies to all engines). Also, unlike road vehicles, aero-engines operate at fixed speeds/loads most of the time, so the flexibility of fuel injection at part loads is of little advantage. Another factor is that sticking with regulated, approved carburetors avoids litigation risks (something that USA has lead the world in). Finally, fuel injection development has been a European (notably Bosch) with early attempts having dismal reliability. USA with cheap fuel found it easier (and initially more reliable) to add cubic inches to get the power. The problem in aviation is that adding unnecessary CCs increases weight above the competition and carburetors can't match current fuel injection, so you have heavish, highish fuel burn, reliable Lycomtinentals. I understand that fuel injected aero-engines don't experience icing like occurs at the reduced temperature at the carburetor venturi throat (Can anyone confirm an icing problems with their fuel injected engines please?). With quality sensors and ECU set up for aviation, correction for altitude, temperature etc can be precisely controlled. I don't like electronics myself because I am old enough to remember failure after failure including early fuel injection, but that seems to be resolved, so I agree that fuel injection is the best way to go, except maybe on very small single cylinder engines. Many USA pilots are my age however, so I suspect the market also dictates what Lycomtinental sells and their big market is USA. Lycomtinental decisions will be made by accountants, lawyers, marketing and the stock market, not start-up engineers. If you like carburetors that is great. They work and are well proven. I doubt it is worth retrofitting fuel injection, unless you are experimenting for the sake of it. The above is all opinion and input from anyone with objective direct experience will override anything stated

I try to be respectful to whoever is happy to read my posts . My posts, that seems to have re-sparked this thread, simply observed that the D-motor is closer to the Lycomtinentals (large displacement, low revving, simple, but at surprisingly low weight for water cooling) than the Rotax. Side valve aside, if D-Motor have done what Lycomtinentals should have done, then we are in interesting times (have improved materials and build quality). You can look at the reliability of Lycomtinentals or do the maths: they will both indicate these motors should be long lived and reliable. I checked your linked paper Mnewbery and it is a theoretical hydrodynamic journal bearing paper (that is a long way from useful in applied engine tribology). The wear and friction of greater concern is rings/cylinders, valve guides .... It doesn't matter what speed: more revolutions = more wear, so a higher revving engine should wear out sooner. The fact Rotax lasts is testament to their build and material quality (NiCrSil). When it comes to stressing, in any engine the highest loads on high-speed engines are generated by acceleration and deceleration of the pistons, each revolution. The Rotax generates proportionately higher stresses due to its higher speed. You don't have to do any calculations to see that. Another engineering measure of 'stress' is power output per cc. The higher it is, the more stressed the motor is mechanically and thermally. Cylinder wear rate is closely related to BMEP, meaning turbocharged engines require special attention in design and build. Sometimes things that appear very simple to the consumer/maintenance have some very complex engineering in them (Tribolgy is incredibly complex, but almost invisible to the consumer except from service life). When I stated the Rotax was complex compared to the Lycomtinentals I was including this in my assessment. I repeat again that my engine explanations are simplistic to avoid lesser details that confuse the fundamentals while not changing the truth. It is great to see post solidly supporting Rotax (I expected it). I was hoping some-one may know more about the D-Motor and D-Motor installs they might like to share. PS: I appreciate you awarding blame for Nuclear Weapons to mathematicians not the engineers :ecstatic:I not sure they viewed themselves to be.

I thought I was stating what was widely known SkippyD . Maybe I should have made it clear by stating ""they are high revving complex things that should fail and wear out quickly IN THEORY RELATIVE TO A LOW REVVING ENGINE" ", all other things being equal.". I thought the last part of my sentence, that you omitted, implied that. Certainly many North Americans promote it because it is true, and they have never faced tight vehicle engine displacement regulations and high fuel prices. In their world there is no substitute for cubic inches:cheezy grin:. Rotax also sells well in USA I believe! The D-Motor is Belgium based, so they must be following American propaganda also. I am aware of enough reduction-drive failures to know you have to do it right, it comes with extra weight and failure risk, favoring the low revving unstressed direct drive engine. To get the power at low revs requires displacement. It is the laws of physics (engineering), not American propaganda. There is no doubt the Rotax is more complex and highly stressed engine. I mean engineering complexity, not just arrangement and parts count. I am impressed by the 4 strokes Rotax has created and their TBO/reliability and would be relaxed in a safe aircraft powered by one. I also don't think Lycomtinentals are doing it as well as they could (so my comparison may imply that Lycomtinentals could have extended TBOs in theory ). I am not sure why you have drawn the conclusions you have given the above is what my post said. I did caveat that it was my opinion based on my background. Like much in engineering is is not just the correctness of the design, but also the build quality that determines the final reliability and performance. The Rotax is a valid design solution that makes up for low CC by high revs giving similar swept volume per horsepower as stoichiometry requires. Simplistically doubling engine speed should double the wear rate and halve the engine life! ... My point was there are now serious contender engines (to be proved by D-motor) available regardless of which camp you sit, so everyone can be a winner, and these are interesting times I will take your post as a sound vote for the Rotax approach and delivery.

Your response left me thinking that crash comics only focus on what people have done wrong, rather than what has been done right. Can you identify practices and circumstances in Gawler that has contributed to this good statistic. It seems like an active club with many members, so your result is meaningful. You have the Adelaide hills, even though it looks pretty flat at the Gawler Airport. If that is you base airport it looks like the Norther Expressway has chopped through your cross-strip and put a fence at the end of you main, so although it looks great it isn't inherently safe. Do you fly safe aircraft makes? Good CFI? Low risk taking community? Good maintenance practices? Good weather? No home-builds? Very interested in hearing your take on it. Do you know other clubs that could contribute their reasons for low crash statistics?

Agree entirely. I am a mechanical engineer with fluid dynamics/CFD, structural and materials background so engines are one thing that I feel able to offer opinions on (I am not an expert and decisions to install should not be based upon my posted opinions). I have been watching Rotax since ANO95.10 days. The fact they have proved reliable is a testament to Rotax getting it right. They are high revving complex things that should fail and wear out quickly, all other things being equal. Clearly they are not, hence my pot shots at Lycomtinentals. They are probably the most reliable, but they are so simple, basic, tested, and with an extensive 'well' trained/governed maintenance structure, it would be hard for them not to be. Since the D-Motor is simpler (if you ignore the electronics or have faith. 4Cylinder variant has 35 moving parts and a TBO rebuild kit for $US 5000 as I recall) than Lycomtinentals , if it has the build quality of Rotax it is a potential game changer, if prices are right. They have had all the woes of other manufactures to take advantage of. They seem to be well backed by Belgium government and the EU (not sure Jabiru enjoys that). Only time will tell and I am looking forward to results (statistically consistent facts) from early adopters. I want good safe reliable affordable and the D-Motor seems to be pushing in that direction. If Jabiru can match it at Jabiru prices everyone is a winner.