Modern engine? What is that?
szutowiczrv10 said:
I have noticed that the only choice we have for the -10 is a lycoming engine for the plane. Do any of you think that three years from now Superior will make a newly designed engine, like the xp360, but a xp 540 for us RV 10 builders that would like to have a modern engine design? Or perhaps a Turbine.
Forget Turbine, the economics make zero sense. Just look at commercially available single engine turbine aircraft, size, weight and cost. Flying 100 hours a year in a 4 seater, unpressurized aircraft with Vne in the low 200's is not an ideal airframe for a turbine. Cessna Caravan, Turbine Air Tractor (Ag plane) or a fast high flying pressurized corporate single turboprop is a better match. The Innodyn is another issue. That is a simple single stage Turbine which I consider "toy" turbine (see other threads).
"RV 10 builders would like to have a modern engine design?"
I don't understand the comments about
modern engine? I hear it all the time but its not defined. The Lyc's and Continental's are air cooled by design. Their lineage is from extensive development over decades by the best and brightest scientest and engineers. There is nothing new under the sun. Granted much of the research and development was done during WWII. True the basics of the engine "Block" (bottom and top end) of our Lycs is bassed on parts unchanged for many decades, that is because it does not need changing, it was done right from the start. However I'll point out new finishes and improvements have been made like these
MODERN ENGINE PARTS.
If you want an air-cooled engine, the Lyc 540 is the state of the art air-cooled, direct drive engine in the 260 HP class. You will not go faster, lighter or with better fuel burn,
SO WHAT IS NOT MODERN?
Now there are advancements for Lycs, like electronic ignition,
cold air induction, roller cam's and lightweight accessories (alternator, starter, prop governor), but the basics of the engine are still the same, as advanced as you need for for and air-cooled, direct drive, 2,200-2,700 RPM, low weight, simple installation, high reliability engine. If you designed an air-cooled engine today it would look like a .......... well a Lycoming.
The materials, processes, tolerances and technology in a Lyc is as high tech as it gets. Some I think are confused by the rough finish of the case and cylinder head fins. They are precision structural castings for light weight and why they look as they do. There's the desire to have a beautiful car engines, machined out of a forged aluminum block with a million valves per cylinder and gee whiz of the latest electronics. If you machined a Lyc case, cylinder heads and sump out of solid aluminum, it would look pretty but weigh a lot more. Precision castings are very modern and basically a work of art.
You see tolerances of 0.002 and 0.005 all over the engine. The valves are like inconel and sodium filled. The crank's made with vacuum arc remelt process, which improves the homogeneity, fatigue and fracture toughness and the cleanliness of the steel and significantly reduces discontinuity formation. Superior claims proprietary Electro Slag Remelt (ESR) process removes more metal impurities than the VAR process. Either way they are very high tech. An auto crank is made with what process? Auto cranks are not required to take the load of a directly driven prop, so you can't compare. If some one whats to bring up crank failures or AD's, that ship has sailed. Yes there was a screw up but as far as crank failures verses fleet, time and hours flown the MTBF is low. Bottom line the AD is preventative and here is an article the addresses this (see part II).
Lyc addresses Crank AD. AOPA's brief on the
Crank AD subject. Bottom line it is a metallurgical problem not a design issue, and it is really a small one in the large scheme of things. If the crank is manufactured properly than it is extremely reliable and overbuilt from a operational, stress, strain and fatigue standpoint.
From my engineering eye
the Lycoming is elegant purpose designed engine; that purpose is an aircraft engine. Any automotive engine you use, no matter how cool technologically, is a work around, make-do, adapt, convert and compromise. In my opinion is look for a used 540 core, get some A&P who know engines to help and learn how to rebuild it and do that.
Air cooling in not old fashion, it's that way by design. You would never tell a Porsche 911 driver his sports car is old fashion. Yes they went to water cooling in 1999 to meet stringent noise standards, also making it easier to meet the most strict emissions, but the air cooled 911 Porsche's are the most desired over the H2O versions.
If a modern engine (water cooled) is better than why are the fastest lightest RV's powered by Lycomings? Why are the fastest racers at Reno racers Air Cooled?
I contend when any one says "Modern Engine" they mean water cooled CAR engine. Yes, car engines are modern engines, modern car engines. Lycs are modern aircraft engines. Yes, car engines have nice features, many driven by electronics, but they are car engines. Yes many car engines have variable valve timing, a million valves per cylinder, which is great when going from idle to 1,000,000 RPM and back to idle a ba-zillion times a day. However aircraft engines live in one very narrow steady state power range 95% of the time, except during taxi, takeoff and approach. You just don't need overhead cam's (which make the engine wider). Plus you don't need long rubber belts to drive those overhead cams, which can fail (It has happened). Not to mention a reduction drive. Those have also failed.
Last there's PLENTY of
air to cool an
air-cooled engines in an
air-plane. If you want a water cooled engine fine, but be ready to do massive R&D and work like RV6ejguy is doing, which is great. All RV's are designed for air cooled engines, not water cooled engines. When RV6ejguy works out that set-up on his RV-10, that may be a great option, but for now your path of least resistance and best (known) performance is building your RV-10 "to the plans", e.g., (I)O-540 Lyc parallel valve.
Last I think some equate modern with CHEAP! Look by the time you get done with your MODERN auto engine conversion it will either cost you massive time or money or both. That makes a new / overhauled off the self "turn key" pretty and painted 540 Lyc for $39,000 a bargain. I still think you can find a 540 Lyc core for $12,000, overhaul for about the same for $24,000 to $30,000 (max).
Every one wants the fastest, lightest plane with a cheap engine. When you find that engine that will do that, let me know, I will declare it THE modern aircraft engine. For now the Lyc comes closest to meeting all criteria and Van's design goals. What water cooled engine fans need is a new airframe, designed around the engine.
Don't be mad, just my opinions and they may be wrong. I can go on about how I admire the efforts of those who try different stuff; I do admire the effort. Bottom line is each to their own. I reserve the right to be wrong, but the
Lycoming is a beautiful modern AIRCRAFT engine, even if based on a 50 year old design. In a sense all engine are based on concepts that are 60-100 year old.
I think the Lyc is the start of the art for an air-cooled aircraft engine, and it's the standard ALL engines, used in small aircraft, are measured by. That is the real telling point.