So a throw away crankshaft is bad design but a throw away cylinder isn’t?
Maybe it doesn’t matter, for the private aircraft owner market, because almost nobody reaches TBO on a specific engine during their flying lifetime.
Depreciation matters too, because that owner will sell the plane and engine some day. I think a throw away aircraft engine installed on an airframe that is intended due to its high cost of manufacture to last a long time, would make that plane have high depreciation… Except maybe for small diesels in a market warped by fuel taxes that are GA killers in their own way.
Cylinders are under $1000 each for my engines and more importantly can be replaced in a few hours by relatively unskilled labor.
The hourly rate of typewriter mechanics also lower than IT experts. And yet there aren’t that many people using those fantastic typewriters with unlimited lifetime, that can be overhauled indefinitely… And shame on those electric typewriters, they are much harder to maintain and have a lot more failure modes!
The classic EuroGA issue… :-) is mistaking machinery for computers.
Ever noticed that some of the best selling industrial gas turbines are very robust, easily maintained, and were designed a long time ago? Solar Turbines are a good example, and they just keep selling. I think it’s a better comparison than typewriters versus computers.
Silvaire wrote:
Ever noticed that some of the best selling industrial gas turbines are very robust, easily maintained, and were designed a long time ago?
Yes, the most efficient gas turbine is a brand new design, delivering 60.75% efficiency in the combined cycle. Obviously not as easy to overhaul as the 1950s agricultural turbines that deliver 40% efficiency at max.
http://www.energy.siemens.com/hq/en/fossil-power-generation/gas-turbines/sgt5-8000h.htm
Sorry but I don’t consider primitiveness to be a value of its own when it comes at the cost of very poor efficiency. It might all work out for one person with very limited use but WW2 was not the pinnacle of humanity and technology has improved and keeps improving and that should be what we’re striving for. The moment I consider past technology to be superior to modern technology, I will officially declare myself as old and retire…
I know quite a bit about Siemens products 
and I’m not retired.
The trick is to recognize that practicality is a marketable virtue, and design it in as well as all the other attributes.
The fact that old, inefficient gas turbines sell in large quantities today while much more efficient turbines exist, it not something I would applaud. For me Citius, Altius, Fortius is what should be driving us. Keep on improving whatever we can improve.
So if I tell you all that EuroGA runs on a 10 year old Thinkpad laptop running Windows XP SP1 and with a 20GB HD, will there be a mass exodus?
If it really was, nobody would know the difference because that laptop could squirt out the data faster than a DSL line could absorb it…
Again – why is a throw away cylinder “better”? Just because it’s cheaper and less practical to operate? We are pilots not mechanics, I for one want something that works, not something very unpractical on the only account that it is easy to overhaul once in a blue moon.
The world moved on from throw away cylinders just like they did from throwaway crankshafts but you seem to conveniently avoid that argument as it doesn’t support your position…
To be fair, cylinders very rarely need changing on Lycos. It is usually due to abuse – excessive CHT under high power, or shock cooling from an initially high CHT. I would agree that in an ideal world such mismanagement should not be possible, but it is IMHO reasonable to add such a qualifier to criticism of the product.
One could thus argue that a Lyco engine balances an increased susceptibility to mismanagement (including mismanaged ownership such as a “hangar queen”) with improved options for servicing.
Ultimately, however, I think the bottom line is that Rotax have not done a product for the bulk of the Lyco/Conti market. So one is comparing products which play in two different markets.
And both do very well in their respective markets.
Why Rotax have not done bigger engines, is perhaps a better question.
