I am also pretty sure there is at least 1 Robin still flying with the Porsche engine.
Unless it was re-engined in the last year or so.
Silvaire wrote:
They missed it due to (as explained) excess weigh and complexity, coupled with difficult field service.
Then explain the diesel engines, Austro in particular. Rotax has completely taken over the O-200 (and lower) market, and is now eating into the 320 with the 915/916. IMO Porsche came with a perfectly good engine, but bet on the wrong horse, the dying one instead of the young and coming one. Porsche would perhaps never go for the 912 market due to snobbery alone, but IF they had, then the 912 would perhaps not even exist. I’m sure Porsche had no clue anyway at that point in time. It’s all history now. The way Rotax looked into the glass bowl and designed exactly what the, by then hardly existing market wanted, and hit a perfect bulls eye with the design, is rather incredible. Since they started selling the first 912 series in 1989, they have sold more than 50,000 of them (in total more than 180,000 when including the 2 strokes, but that started much earlier and powers all kinds of winged contraptions).
Silvaire wrote:
In relation to the higher power market, although it’s hard for me to imagine many of the e.g. 11,000 RV builders choosing other than a more practical Lycoming
800 of those are RV-12 with Rotax engines 
But all those Lycomings for the RVs are not really Lycoming. Most of them are either clones or rebuilt engines using non Lycoming parts. The design itself is very good and practical, but only when gasoline (100LL) is dirt cheap and weight is no issue. Today it’s mostly an overpriced collection of dubious engine parts. I mean what exactly do you pay for? Development that ended for good more than half a century ago?
The Porsche engine came right when the market started turning. The incentives for something new at that time suddenly evaporated over night. That’s how the situation has been ever since. Austro is more a product out of stubbornness and creating the right package (Da 42) for a specific job, pilot school training.
Then explain the diesel engines
Monopoly in the FTO market. The Porsche engine was not in a strong position.
Then explain the diesel engines
As said clearly in my original post 04, the Porsche engine did not supply an offsetting benefit to help justify its weight and complexity. The diesels do supply an offsetting benefit, better specific fuel consumption, making them more viable to some buyers in some markets. Also the use of Jet-A in some places although in the world’s largest (US) GA market that is a disadvantage so they don’t sell in measureable volume there.
As you might know (or not) I make my living in something along these lines. There are some fun stories involved about Thielert, Austro and the Lycoming/Fiat DEL-120.
Explaining the world GA market from the very narrow and unusual perspective of somebody who flies and buys (only) in one tiny country with a tiny GA market (Norway) is not very productive, as has been pointed out a lot of times.
The Robin book has a page on the PFM320.
It’s a 6 cylinder from the 911, rated 212hp at 5,300 rpm and 200hp continuous at 5,000rpm, with electronic ignition. Robin were quick to try it in the DR400, but had to design new cowlings; first flight 24 May 1985. A reduction gearbox driving the propeller, and muffled exhaust, made it quiet. Compared to a normal DR400-180 the single power lever made it easier to manage, and fuel consumption was less. However, it was more expensive to buy, and heavier at >185kg (I guess 120kg for an O360).
The DR400-212 was certified in 1988, but only 35 were produced. Mostly onto the D-reg, with most of those as the -212R or ‘Remo’ glider tug. Porsche found the engines not economically viable, probably linked to some problems with detonation using automotive fuel and/or crankshafts breaking (‘rupture de vilebrequin’ in French). Long term the TBOs turned to be shorter than for a Lycoming.
This plane spotter website shows a few of them. With the cowling off it looks pretty complicated.
Edit: the other Robin book has some more details. Pierre Robin wanted to move toward using European car engines, and the PFM3200 was the fourth engine tried; it proved a costly and futile exercise for the company. Quantitively it was 40% quieter than the Lyco version.
The performance figures are better compared to the fixed pitch 180hp, but I suspect equal to a 200hp injected Lycoming and constant speed propeller, which Robin were already using on the HR.100 series.
Silvaire wrote:
Explaining the world GA market from the very narrow and unusual perspective of somebody who flies and buys (only) in one tiny country with a tiny GA market (Norway) is not very productive, as has been pointed out a lot of times.
I didn’t mention Norway at all. It’s not in Norway those 50,000 Rotaxes have been sold Lots of them there too of course, but only a tiny fraction of those 50,000. Let’s stay focused. I explained about the Austro myself. It’s packaged with a Diamond twin, and flight schools find that it is a good and cost effective solution, better than anything else in fact. That and pure stubbornness by Diamond. The engine itself however, is as complicated and heavy as it gets, and is used nowhere else. How americans “feel” about that is pretty much irrelevant
There’s no good reason why Porsche couldn’t have done the same thing, except the market was turning another way, and it didn’t really offer much better than already existed. But if Porsche did have the same glass bowl as Rotax had, they could easily have changed aviation history at that time. They bet on the wrong horse because they didn’t know of any other horses, and perhaps couldn’t care less if they did.
It’s not about “feel” it’s about what sells based on market demand – which in this case (circa 200 HP engines) is all about power density and practicality. The 200 HP market was in full swing when Porsche introduced their engine (and is still healthy today) but the market bought only about 80 Porsche engines as a result of the engine’s deficiencies.
Little Rotax engines powering ultralights in 2024 are fine but irrelevant to this thread.
@Capitaine, I wish I could read more about Robins in the language of their manufacturer. They are really interesting when viewed from afar.
Silvaire wrote:
It’s not about “feel” it’s about what sells based on market demand
Exactly. Rotax knew (somehow) what the future market demanded. Austro came out if some stubborn demand by Diamond exclusively. Lycoming exists as it is today due to almost zero market demand. No one with their head screwed on right would try to enter that market with something new (some always do of course). It’s a dwindling market, and has been so for the last 40 years at least.
What kind of cars would we have today if the demand started heading straight down 40 years ago? At least in Norway (sorry for mentioning this tiny and irrelevant country in a conversation with the “big guys” ) there would be a whole bunch of Volvo 240s, that’s for sure.
Silvaire wrote:
Little Rotax engines powering ultralights in 2024 are fine but irrelevant to this thread.
Those little rotax engines sell in greater numbers than Porsche could dream of in their wildest dreams, and the same goes for Lycoming and Continental today. That’s the point. No matter how good or bad the Porsche engine was, it was the wrong product at the wrong time, and Porsche had to make the decision to cut their losses.
We have had various threads on why car engines can’t be used in planes. It is a persistent question in GA. Car engines seem to be incredibly reliable and just go on for ever. So why not in planes?
The main reason is that they are not reliable when running at high power (say 60%) continuously. In a typical modern car, say 120mph max speed, at the typical national speed limit of say 70mph, the engine is running at maybe 30% of max power. That is why they rarely break.
And still some break. I work above a KIA dealership and while KIA is hardly a traditional paragon of quality, they can’t be that bad and offer a 7 year warranty. Yet I see loads of broken engines there. They get repaired.
Also liquid cooling is not that reliable. It is a frequent failure point in cars. My Toyota had its only breakdown via a coolant loss. It can be made fairly good with good engineering…
I imagine the Porsche engine suffered from all these problems. The Diamond diesels had loads of problems too but the “experiment” survived because of
