Greg Dillon
Active Member
I know it's a turboprop, but the Tupolev TU-95 has counter-rotating props and is expected to remain in service till 2040. Maybe the Russkies know something we don't about gearboxes and c/r prop systems?
<SNIP>
Question: Does anybody know of an experimental gearbox with 1000 hrs on it?
No, there have been some faults in the gear wheel metal lately. This is fixed with the newest SB.No Rudi, the Rotax 914 is certificated, not experimental, and as such was conceived with real engineering and thoroughly tested. It also employs a clutch mechanism which limits torsional vibration. Even with all this, I understand that the gearbox has many premature failures and overhauls.
No, there have been some faults in the gear wheel metal lately. This is fixed with the newest SB.
IMO the Lycomings are great engines, superb engineering. However, the design is old, and what was superb 50 years ago is not that great compared to what is superb today, crocodile or not My bet is that if the original designers of the common Lycoming variants we see today were to design a new engine from scratch, they would end up with a larger 4/6/8 cylinder versions of the Rotax 912 - with gear and liquid cooling.
I don't agree. After 105 years of aircraft engine developement, air-cooled, direct drive engines have proven to be superior. Let's not forget that most engines WERE watercooled in the 1910's and 20's and 30's. Most were geared during the 40's and 50's. If this technology was superior, don't you think it would be in wide use today? Not only are geared engines NOT in wide use, every manufacturer that tries has difficulty keeping them together.
Why keep trying to pound a square peg into a round hole? Embrace the beautiful simplicity of the aircooled, direct-drive engine.
The 1911 Colt pistol, named after the year of its introduction, was also a superb design with great engineering. Ninety-seven years later, it is still being produced by Colt, and by dozens of other manufacturers including Colt's arch-rival, Smith & Wesson. If you can't beat 'em......I guess. Anyway, in some cases, you don't need to re-invent the wheel- it's perfect the way it is.
Why not use what Cessna, Piper and others count on as their best insurance for keeping the lawyers at bay. If they thought a cobbled together car engine derivative would reduce their liability, they would be all over it in a heartbeat!
I think you are mixing cause and effect and theology and engineering here The lycomings are not great engines because they are direct drive, air cooled, low rewing, large displacement engines. They are great engines because they are extremely well engineered pieces of machinery utilizing all the benefits of direct drive, air cooled etc. But the thing is - you can say the exact same thing about air cooled VW engines and their conversions (Sauer and Limbach notably), and they were never even meant to be flying.I don't agree. After 105 years of aircraft engine developement, air-cooled, direct drive engines have proven to be superior. Let's not forget that most engines WERE watercooled in the 1910's and 20's and 30's. Most were geared during the 40's and 50's. If this technology was superior, don't you think it would be in wide use today? Not only are geared engines NOT in wide use, every manufacturer that tries has difficulty keeping them together.
Why keep trying to pound a square peg into a round hole? Embrace the beautiful simplicity of the aircooled, direct-drive engine.
These are "better" only in that the allow the use of Jet-A fuel. As such they will only make economic sense in areas where avgas is not available or cost prohibitive. The may sell well in Europe (for a lot more Euros) where avgas is expensive in comparison to jet-A if available at all. But in areas where avgas remains available and is more cost effective (here in the US diesel is more expensive than mogas and Jet A is more expensive than avgas-I won't go into energy content), that Thielert diesel is a gold plated paperweight. With the price points for these Cessna equipped Thielert's however, it may make more sense to just buy expensive avgas.Cessna is now installing Thielert diesel engines in their products. Liquid cooled, geared and automotive based. Times do eventually change. Customers must have wanted something other than Lycos and Contis or Cessna would not be offering these. They are certainly not cheaper.
I personally don't think that engines like these will replace direct drive Lycos for most GA aircraft until cost and weight comes down and they actually reach TBR on a regular basis but times are a changin'.
Why keep trying to pound a square peg into a round hole?
These are "better" only in that the allow the use of Jet-A fuel. As such they will only make economic sense in areas where avgas is not available or cost prohibitive. The may sell well in Europe (for a lot more Euros) where avgas is expensive in comparison to jet-A if available at all. But in areas where avgas remains available and is more cost effective (here in the US diesel is more expensive than mogas and Jet A is more expensive than avgas-I won't go into energy content), that Thielert diesel is a gold plated paperweight. With the price points for these Cessna equipped Thielert's however, it may make more sense to just buy expensive avgas.
I too don't see the benefits of the Thielert engines in North America at this time for most GA aircraft due to the scarcity of jet fuel at many small airports, cost of the engines and fuel and the lack of longevity demonstrated to date.
Merely countering the observations in another post here.
That fire would not have happened with diesel fuel.
Lycoming and the likes are as adapt to their environment as the Dodo was...
drench yourself in diesel or avgas, in which situation would you rather strike a match ?
The atomisation only takes place in the instance of impact.
In this case the fire broke out "long" after that...
drench yourselve in diesel or avgas, in wich situation would you rather strike a match ?
I suggest you take a rag soaked in diesel and light it before you advocate it being safe.
Anyone that has started a charcoal fire using a match and lighter fluid knows how easy it is to light.
I am sorry for the loss of any pilot, but AVGAS should not be blamed. If he grabbed the wrong control knob it was pilot error pure and simple. I was taught that if you move a lever and the engine quits undo what you just did!
Diesel, on the other hand, has a relatively low vapor pressure, so the environment inside fuel tank is ripe for ignition with a nice mixture of fuel and oxygen available for the reaction.
The most public example of jet fuel igniting like this inside of an enclosed tank was the 747 that went down over Long Island. The cause was a shorted, sparking wire inside the fuel tank.
Tim
wich is why we constantly see diesel powered cars and trucks blow up by the thousands
The jury is still out on that one as to the REAL reasons...
Reading this thread for this first time this got my attention. I wonder what the author is trying to say. Newton figured out that Force = Mass * Acceleration, so the statementStress is caused by inertial force as pistons and other parts are accelerate or slowed. Inertial load or force or in other words the "stresses" increase at the square of speed, but linearly with force. Which means that if you double the mass of the objects you double the force, but if you double the speed or more accurately the rate of acceleration, you quadruple the force.
is not true.if you double?the rate of acceleration, you quadruple the force
Only a few weeks back the founder of the LEKI company here in germany survived the crash of his Extra, but was burned alive in the ensuing fire. His copilot tried to get him out but was driven away by the flames.
That fire would not have happened with diesel fuel.
You might want to ask his wife what she thinks of AVGAS
The whole ACCIDENT would not have happened, since it involved mixing up the mixture lever with another one.
Over 60 years ago there were already single lever engine operations on complex high performance engines.
Lycoming and the likes are as adapt to their environment as the Dodo was...
Lycoming and the likes are as adapt to their environment as the Dodo was...
Gentlemen,
this thread has taken a vector in a different direction from its original intent.
Reading this thread for this first time this got my attention. I wonder what the author is trying to say. Newton figured out that Force = Mass * Acceleration, so the statement
Quote:
is not true.if you double?the rate of acceleration, you quadruple the force
Well Herman, the Dodo was actually a bird that was so overweight that it couldn't get off the ground which is what ultimately led to its extinction.
So in that regard it would appear that all of the obese GA aero-diesel engines that have appeared and then promptly become extinct in recent decades have more in common with the Dodo than the excellent power to weight ratio Lycoming which is still very much alive and thriving.
Errr,
the Dodo was a bird that could only evolve in such a fatal way because it had a MONOPOLY
Wich ist what Lycosaurus and the likes enjoyed thus far. When said monopoly ended.....
So far the monopoly is still being enforced through massive papwerork costs.
Errr,
the Dodo was a bird that could only evolve in such a fatal way because it had a MONOPOLY
Wich ist what Lycosaurus and the likes enjoyed thus far. When said monopoly ended.....
So far the monopoly is still being enforced through massive papwerork costs.
I have observed that an opinion on VansAirforce tends to carry more weight when the author puts his name to his post.
I have observed that an opinion on VansAirforce tends to carry more weight when the author puts his name to his post.
Try Playing the BALL and not the MAN when reading any forum.
It would even be better if everybody who posted on this forum also contributed $25 to Doug's Vans Airforce, don't you agree Captain?
Barry Ward RV6a F PRVM
Back to the original thread and in reply to our German friend Herman. Perhaps he is is not aware that several years ago the German car manufacturer Porche decided to get into the business of developing a replacement for the Lycoming engine .
Their engine which was a single leaver 200 power unit was installed in a specially developed Moony. In spite of the technical engineering excellence of Porche as well as their considerable finacial resources the whole thing turned into a fiasco. All the planes had to be reequiped with Lycoming or Continental powerplants.
Barry
...several years ago the German car manufacturer Porche decided to get into the business of developing a replacement for the Lycoming engine ...
...It's often been said that Porsche has forgotten more about engine design than aviation engine manufacturers ever knew. Porsche mistook a compliment for the truth and never bothered to find out the few things that Lycoming and Continental did know...