That comparison has been made before, but I never saw the other one – I always keep apart from the mainstream. The “down to earth” part is what I really like about it!
Better food (organic, free range, non-farmed fish, etc)
I see such comments from time to time. Free range, organic, and in particular non-farmed fish. The quality may be OK, but it may also be terrible. Free range and non-farmed are not quality stamps, they are just descriptions of a non-essential attribute, more like the color of the cow. Salmon for instance, a fully grown non-farmed salmon is full of microscopic parasites and other nastiness that may make you quite sick. This is natural and cocking or smoking usually removes the toxins. All salmon served at Japanese sushi bars are farmed due to this. The highest quality salmon is farmed, some low quality salmon is also farmed, but non-farmed salmon is almost always of bad quality unless you go fishing yourself and get some trout and mistake it for salmon.
Anyway, what has this to do with fuel?
Just so we put the “bad tech bad design” argument to rest – 4’000 Centurion (inc. Thielert era) engines have been delivered thusfar. IFSD rate as of 2013 is better than avgas engines (0.61 /100k flight hours). So I guess we’ll have to split into two groups – one which likes old technology because it’s cheap (cheapness apparently not being an indicator of build quality) and another one who likes new technology because it’s less likely to fail in flight.
Peter, yes, the accelerator pedal and the key falling out of GM’s ignition switch and and and… are design debacles. Fully agreed. But then again, how much did it cost the customer to fix them? On the other hand, you had to spend what, 15k USD to fix an engine which is worth what… 60k USD new? The customer having to spend 25% of the purchase price to fix a design/production flaw is hardly indicative of good craftsmanship to me…
All piston aircraft engines are not well designed and occasionally are not well built but the volume in the market is too small to attract the very high level of R&D, advanced manufacturing techniques, and QA which cars get.
All manufacturers in GA, whether it is engines or avionics, struggle with
So we are stuck with what we have, I think.
BTW, can you post a reference to your in flight shutdown data? Lots of people have looked for stuff like that but never found anything particularly good, for various reasons starting with many/most engine failures bing unreported – because they are usually not total/catastrophic, or they occur on twins enroute.
I’ve had many debates over e.g. “making TBO”. To me, “making TBO” means making 2000hrs without any work other than cleaning spark plugs etc. To a TIO-540 owner, “making TBO” means making 2000hrs without opening up the crankcase 
And people get very religious about this.
So I ask about where exactly your data comes from. I believe it doesn’t exist on Lycos/Contis (there is no system for collecting it in any usable form) and when it comes to Diamond/Thielert/Austro (i.e. a single source, basically) it will prob99 be massaged; the whole Thielert business was massively massaged, by both suppliers and the customers (who were mostly FTOs and did not want to wash their dirty washing openly).
All piston aircraft engines are not well designed and occasionally are not well built but the volume in the market is too small to attract the very high level of R&D, advanced manufacturing techniques, and QA which cars get.
In which way would the SMA engine lack on these criteria? In which way would a 2014 Centurion/Austro lack?
Some of these may start as car engines (in the basic building block) but the rest is custom add-ons.
Yes but I still don’t see where SMA/Thielert/Austro of today would lack in “R&D”, “advanced manufacturing techniques” and “QA”. According to your criteria, I would consider them to be lightyears ahead of the avgas engines where manufacturing involves a 65 year old guy with a rasp machining the part…
avgas engines where manufacturing involves a 65 year old guy with a rasp machining the part
Ignoring the stereotype (you will be 65 one day too ) the real Q is whether this matters.
The technology in my TB20, mechanically, is similar to that in my Honda lawn mower. I am actually very happy with that.
What you may be referring to is the lack of production line automation, in GA engines. Obviously, this is due to the volume being about 1000 times too low.
But Thielert (etc) that use ex car engines just buy the engine, throw away the accessories (reportedly stuff like alternators get removed and scrapped) and bolt on their own low volume accessories.
But Thielert (etc) that use ex car engines just buy the engine, throw away the accessories (reportedly stuff like alternators get removed and scrapped) and bolt on their own low volume accessories.
Thielert machine their own crankcases, manufacture their own gear box, clutch, etc. There is not much left from the Mercedes parts. The Austro is much closer but for that reason much heavier. The design and manufacturing process is similar to the automobile industry and so are precision and tolerances. When Lyco/Conti undertook their last R&D effort, there was no CAD, CNC or anything.
Has there been an in flight failure of the SMA engine? With the Austro engine? Any with the Thielert 2.0 in the last 3 years?
Just so we put the “bad tech bad design” argument to rest – 4’000 Centurion (inc. Thielert era) engines have been delivered thusfar. IFSD rate as of 2013 is better than avgas engines (0.61 /100k flight hours). So I guess we’ll have to split into two groups – one which likes old technology because it’s cheap (cheapness apparently not being an indicator of build quality) and another one who likes new technology because it’s less likely to fail in flight.
Peter, yes, the accelerator pedal and the key falling out of GM’s ignition switch and and and… are design debacles. Fully agreed. But then again, how much did it cost the customer to fix them? On the other hand, you had to spend what, 15k USD to fix an engine which is worth what… 60k USD new? The customer having to spend 25% of the purchase price to fix a design/production flaw is hardly indicative of good craftsmanship to me…
Rotax has sold 50 thousand 912/914 and their sales are accelerating. It is the most-selling civilian piston aero engine ever. Lycoming has sold, what? several hundred thousand all together, but lots of different engines. Even Limbach has sold 5-6 thousand engines. My point is this: Lets compare a Centurion and a 914, both being turbocharged and delivers power at altitude:
HP max: Centurion 133, Rotax 113
HP continuous: Centurion 133, Rotax 100
Weight, kg: Centurion 134, Rotax 75
Fuel consumption at 75% cruise: Centurion 15-20, Rotax 12-15
OK. Lets scale up the Rotax to 133 HP continuous, what do we get:
HP max: Centurion 133, Rotax 150
HP continuous: Centurion 133, Rotax 133
Weight, kg: Centurion 134, Rotax 100
Fuel consumption at 75% cruise: Centurion 15-20, Rotax 16-20
Further, lets assume we bolt on the FADEC from the 912 onto the 914. This gives us a 20-30% reduction in fuel consumption and a tiny bit more HP. A 914 cost about 25 k€, the scaled up version would cost about 30 k€. A Centurion cost what? 60k, 80k, 100k ? Besides, the specs are like that of a Lycoming 320 costing less than 20k. The numbers speak for themselves.
I have been working for more than 20 years developing technology for the oil and energy sector. Turbines mostly, and I have been flying for 35 years. My honest opinion is that I see no future for engines like Centurion and SMA. They are not good enough, not even close. They are way too costly and technologically complicated and heavy for the task they are set to do (propel an aircraft from A to B). Sure, lots of people buy into it and get all religious about diesel/jet fuel and total cost and total package, potential cost savings and whatnot, and for some small niche of customers it may actually work out it they remain very focused. But for 99% of us, these engines make no sense whatsoever. I too dislike the fact that Lycoming/Continental does not invest a single dollar in R&D on their bread and butter piston engines, but one fact still remains about those engines, those engines are true masterpieces of engineering design, Lycoming in particular. The only other engine that comes head to head is the Rotax 912/914 (I must add I also like ULPower and also VW conversions for their function and simplicity, but they are nothing but slight alterations of the general theme of a Lycoming). It is not without cause that Rotax and Lycoming are found in at least 95% of all private aircraft flying. It is not a dwindling market that has caused this. The main reason is that it is close to impossible to make anything better, and completely impossible to make it at lower cost. This will not change until we see a true change of paradigm, like electric power, or something else we do not yet now about.
In the near future we will see a substantially reduced bureaucracy from the aviation authorities regarding GA. Things will loosen up, and most of GA will live in a climate of less regulations, much more similar to ultralights and experimentals. My prediction (for whatever it is worth ) is that this will enhance the importance of simple things that just work. Rotax will definitely be a part of this, as will ULPower. Lycoming will also live well in this climate because there exist an entire jungle of aftermarket suppliers already. Aftermarket suppliers will be a key factor, no engine will be able to survive without it. Things like Centurion and SMA that requires industrial scale planning from the users to keep the cost in check, no chance.
