I think the problem is that car engines spend on average almost no time at high power.
Even at 65%, continuous, your license would last less than a day. Actually you would end up in jail (in a police station, awaiting bail etc) the same day.
Rally car engines get a bit more “usage” and they get trashed rapidly. There are exceptions but I am not sure they are representative.
Even after all the years, Thielert are still not on a straight 2000hr TBR, never mind a TBO, and (see the links Jonzarno posted today) the realistic Lyco TBO is way past 2000hrs if you manage the engine intelligently. I know avgas cost dominates by a huge factor over the engine fund of a Lyco but…
Yes, tell Mr. Thielert and Mr. Porsche etc. about gearboxes 
It’s very difficult. Austro were more conservative which much heavier components and fewer optimizations and they seem to be doing better. It’s not the aero engine one’s been dreaming of though…
Even after all the years, Thielert are still not on a straight 2000hr TBR, never mind a TBO,
SMA is at 2300 TBO and are planning for higher and that for an engine that is rather new to the game. Thielert should go up too now that there is money to be spent on R&D. During insolvency, they were legally prohibited from investing anything.
We.. the PORSCHE gearbox worked pretty well, I would say. And even the Thielert one improved over time. And, no, i do not think that Thielert is on the same level as Porsche or Daimler
We.. the PORSCHE gearbox worked pretty well, I would say.
No it didn’t. So badly that Porsche had to buy a new prop for all Porsche Mooney customers. Originally it had a 2 blade metal prop but they couldn’t make gear boxes withhold the torque pulses so they all had to be replaced by 3 blade props from MT. Porsche were no idiots and neither were Thielert, it is a damn difficult job. Most of the remaining Porsche fleet is being serviced here at my airfield so I get to hear some interesting stuff now and then.
On a side note: a Porsche Robin had a prop strike recently at our airfield (drove over a runway light). A prop blade broke off in the middle. The job consisted of sending the prop to MT for repair/replacement and changing one small part in the gearbox. The prop was expensive, the gearbox repair was a piece of cake. That is a huge advantage over a direct drive engine as Peter can confirm
AFAIK there is no remaining Porsche fleet. Or is there!?? Didn’t Porsche buy out all engines?
Well a propstrike is a propstrike … and will ruin any gearbox i guess ….
AFAIK there is no remaining Porsche fleet. Or is there!?? Didn’t Porsche buy out all engines?
There are about 30 or so still flying. Excellent engine, I think currently 5 of them are stationed here in EDTH. Porsche Robins, Porsche 182, Porsche Mooneys. The latter are the nicest. The only thing I do not like about the Porsche engine is its dry sump lubrication which means you have to turn it on, run it for 3 minutes, turn it off, leave the airplane, check your oil level and climb back in. Same as Rotax where you handprop until it gurgles. Racing cars like Porsches need a dry sump, no space and can’t afford to have the center of gravity a mm higher because of the oil sump
Well a propstrike is a propstrike … and will ruin any gearbox i guess ….
The contrary. The damage to the prop is nothing compared to the cost of an engine teardown which you do not have to do with a gearbox. In the above example, the repair to the gearbox was very simple and cheap. Just replace one component. Since last year, I know all about prop strikes and Lycomings
That is a huge advantage over a direct drive engine as Peter can confirm
You are describing the post prop strike regulatory position, which I do not think has any different engineering basis to any other engine.
I have been told by numerous engine shops that some 99% of shock loaded engines turn out to have no damage following inspection and NDT. The full shock load treatment is therefore a strongly precautionary position.
However, among the more common defects that are found, are cracks in the accessory gearbox gears. I thus do not believe that the presence of a gearbox is going to protect the engine (or even itself) from shock load events. I think these newer engines are simply “lucky” by not having been exposed to the UK litigation / back end covering climate so they allow these procedures.
Even on Lycos the procedures change over time. When I had my pothole prop strike in 2002, it was legal to forget the prop repair and just cut 20mm off the end of each blade, and it was legal to forget the shock load inspection if the prop flange was not bent. In fact it was legal to do nothing with the engine (not even check the prop flange) if the engine did not completely stop during the prop strike (which is basically what you describe for the gearbox scenario). And, yeah, what do you think the average owner with say 1500hrs on his engine is going to do? Insurance will not cover betterment so he won’t get an overhaul out of it. And if the engine is opened up, it cannot be released to service if any “worms” are found, so it could trigger an overhaul (because a “repair” at 1500hrs is not cost effective unless done really on the cheap). Many would have opted for the easy way out… maybe disposing of the engine into the exchange marketplace 
The damage to the prop is nothing compared to the cost of an engine teardown
My prop was about 10k and the shock load inspection was about 6k. All plus VAT.
Any significant prop damage needs new prop blade(s), unless you really don’t give a damn and are happy for somebody to just hack the ends off (and fly with the resulting governer-adjusted coarser pitch afterwards). And replacing blades may trigger a mandatory scrapping of the hub – NDT is not allowed even if you did a CAT scan, so this is another regulator position with no engineering basis.
new thread, propstrike? ;-))
