Lycoming Superiority

[rv6ejguy]

rv6ejguy,
Sodium filled valves tend to be bulky and very expensive- seen occasionally, but "commonly found" might be a bit optimistic outside of racing circles. Are they even available for Lycs, Subaru's, etc., we are discussing here?

From your F/A notes targeting 13:1 ratios in boosted operations, I'm curious if you run only 100LL in your turbocharged engine? The turbo guys I know prefer a little wider margin-of-safety running turbos on mogas, particularly given subtile differences in pump gas quality. 100 octane would provide an excellent safety buffer.

Regarding turbocompounding, the process was hard on exhaust valves in the reciprocating engine trials (source of parts bin comments?) - My understanding is that the achievements reported were based on downgraded (limited) output levels and not optimised. Removing exhaust valves from the equsion eliminates a major limiting obstacle.

The 35% efficiency estimate I referenced came from Paul Lemar who has recently completed a prototype system for his rotary engine and has posted data on his website at http://www.rotaryeng.net/turbo.html ; the next step involves obtaining dyno data to provide credible comparions.

Sodium filled valves are common in aircraft engines and in the STI Subaru but relatively uncommon in other auto engines. They don't seem to be required even in racing applications. I've used stock type valves in all my turbocharged racing engines and never had a burnt valve. Most auto valves use a two different alloys for the head and stem.

For road racing and aircraft, we tune AFRs for 13-13.2 in most cases for max power. Richer costs power. We never run close to detonation margins in these applications are you are just asking to blow something up. Fix is proper timing, proper octane and proper CR to go with the manifold pressure and hp targets.

The turbo compounded R3350s were the highest output ones available if memory serves me correctly. 3750-3800 hp in one version with water methanol injection. You are right, these were not the most reliable engines in the world in this form. My father flew maritime patrol in Argus' and Neptunes fitted with these engines. The Neptune had 2 jets also so if the Wright packed up on one side over the ocean, it was not so scary. The standard quip was- "two turnin' and two burnin'"

PL is a great theorist but many times has been proven wrong by people actually doing it and he still isn't flying a Wankel after all these years. He has often insisted he is still correct after several people have proven him wrong through empirical testing. With no more than 40% of the total fuel energy contained in the exhaust in the Wankel, it would take an extremely efficient turbine and coupling system to recover 35% back to the eccentric shaft. We are talking 85-100%. Consulting one of my old texts says this is highly improbable especially considering that small turbines rarely exhibit efficiencies of much over 80% alone. Allison experimented with turbocomponding on their V-1750 (E-27) near the end of the war (it is a huge device). BSFC was improved from .47 to .392 which is pretty impressive but nowhere near 35%. I think Wright found similar gains. I await the dyno results to confirm PL's theory.

 

[Bill Dicus]

Lyc

Mechanical devices like mags are pretty reliable! It's sad to note that one of the two powersport rotary RV-8's was lost due to electical system failure. How did that happen? I thought the electrics were redundant. That was a beautiful airplane and climbed/cruised very well. It was terribly noisy, apparently. I love Lyc's and feel comfortable after thousands of safe hours behind them. There's one going on my -8. Would love to see a good alternate power plant like everyone else. Bill

 

[Bill Dicus]

Lyc

Mechanical devices like mags are pretty reliable! It's sad to note that one of the two powersport rotary RV-8's was lost due to electical system failure. How did that happen? I thought the electrics were redundant. That was a beautiful airplane and climbed/cruised very well. It was terribly noisy, apparently. I love Lyc's and feel comfortable after thousands of safe hours behind them. There's one going on my -8. Would love to see a good alternate power plant like everyone else. Bill

 

[cjensen]

It's sad to note that one of the two powersport rotary RV-8's was lost due to electical system failure. How did that happen? I thought the electrics were redundant.

He did have redundant electrical systems...they both ran thru a single switch that failed. That was my understanding anyway. Correct me if I'm wrong, someone.

 

[rv6ejguy]

That is correct by my recollection. The NTSB database is currently down but you can get the report by searching jim clark, rv-8, sonoma. Fortunately Jim survived a hairy forced landing in a vineyard.

This drove home the point about total electrical redundancy in non magneto/ EFI aircraft. Two busses, two batteries, two switches etc.

A sad end after flying these beautiful aircraft against Van's demonstrators and showing they had the performance albeit with higher fuel consumption and noise.

 

[Jconard]

Sodium filled valves were available and used back in 1973 in 914 2.0 cars, and are the OEM replacement of choice for buses and 914's.

Just to point out that Sodium valves are really not exotic or rare.

Most air cooled race engine builders however have had equally good luck with stainless steel valves. And I believe that most OEM's now depend more on good valve stem machining and heat transfer out of the valve.

Lycoming valve stem is huge and stainless steel, and I cannot remember any stem breakage issue. Such size would be a problem at High RPM, but works great in its intended application.

As for eliminating the exhaust valve issue by turbo compounding a rotary....heat retention at the ALUMINUM ports is as much a problem as heat retention on a steel valve.

The reason the rotary responds so well to turbocharging on the other hand is that it is not very efficient thermally, and there is alot of lost heat energy in the exhaust. For top thermal efficiency, I am pretty sure you would look at a high CR piston, with perhaps a turbo, diesels look awfully good.

How much improvement would justify the cost or complexity? At optimum a good trad engine has about .46 BSFC http://www.eci2fly.com/exp/images/IOX-340SPerform.gif


And, BMW has anounced testing a turbo compounded test car...12% or so.

Exciting stuff...perhaps alot of changes in my lifetime.

 

[gmcjetpilot]

Wow this fire flared up

Good points xl1200r, and well stated. Your comments about RPM are correct to some point, obviously, and I don't think you where bashing. True high REV means more cycle and more wear, and that applies to Lycs as well. However a Lyc is designed to operate at low RPM. The other side are higher rev engines are designed for higher RPM (kind of). Sure, longevity, no doubt, from logic is related to RPM. Probably more correctly % power.

Car engines run at very low % power most of the time. Most are not using peak power ever, espcially if Grandma is driving. Occasional transient, hard acceleration, passing up a hill gets your car engine near peek power. Car engine power is rated at high RPM, where a Lycoming HP is rated at 2,700 RPM, where it's designed and tested to run 24x7. As long as temps are within limits you can't hurt a Lyc. YES, a Lyc running at high RPM and power will wear faster, obviously. That's why even Lyc recommends 75% or even 65% for max life. Regardless, RPM and % Power are relative to wear no matter what engine you have. The Lyc is designed to run at 75% power and still have a long (TBO) life. On the other hand a car or motorcycle engines are designed and typically run at way less than 75% power. What does that mean? Well rv6ejguy is right there is no data. However I have heard some car makers (and even bike manufactures) destruction test their engines at near 100% pwr and they only last for a finite duration. Where I have run my Lyc wide open for 2.5 hours in a race, maintained temps and had no long term affect, based on later compression test, oil analysis following the event, over say 100 hours after resuming normal flying. Did I reduce the life? Sure probably, no doubt. Thus the point, any engine operated at higher pressures temps and RPMs will not last as long. The Lyc is so under tuned that it's 100% power is a low stressed deal. I know there are 24 hour long distance auto rally race stories, but those engines are not left in service much longer after that race. Its kind of hard to compare car, motorcycle and plane apple orange wise. Aircraft have no room for failure, which is the big difference.



xl1200r: "to mention you have to look at the power gain. I ride a 1200cc Harley-Davidson"

I love pointing out the 2006 point standings for Pro Stock Motorcycle had Andrew Hines #1 in points up to this week (two races to go). (http://www.nhra.com/stats/points.htm
) 6 of the top 10 points leaders are on H-D's, 4 Suzuki. So BIG V-ee twins are beating the high Rev'ers down the Qtr mile. 2005 Pro stock winner and 4 of the 5 top where on H-D: ( http://www.nhra.com/stats/points_05.htm ) Yes there is a big parallel between H-D and Lycoming. In "Air races" the winners are powered by Lycoming or Continental. Competition aerobatics? Forget about an auto engine. The claims of superiority for Lyc, I buy it, at least in an airplane. It would make a terrible car or bike engine.

Allow me to introduce you Mr. xl1200r to rv6ejguy and corbra. If you did not notice one is a fan of Subaru powered planes and the other is a Wankel, fan. I am sure you noticed, we all have opinions. Good guys and they have their perspective as you and I do; obvioulsy you have some background to support your comments; I tend to agree with your point of view. Simple, light, reliable direct drive air cooled engines are well suited for small aircraft (and motorcycles). You notice without being asked rv6ejguy brings up weight of a Subaru and Cobra brings up fuel burn. I wounder why?



rv6ejguys: "I've ridden a Ninja 900 many years ago and sat on running Harley's. As an engine guy, there is no comparison in refinement between the two and you must be a tough lad to ride a V twin for 8 hours!"

I have many miles on in-line 4 rice burners and they're great. My bike of choice now is the BMW "air head" R1150RT. The 1150 engine was the previous version to this years 1200cc 122hp BMW Boxer, that xl1200r mentioned. They are awesome. The new 1200 twin engine looks like the previous 1150 engine but is really a new engine with a counterbalance shaft. It is almost too smooth. An Amazing Horz opposed twin, but don't call it air-cooled, the German's don't like that. It's air/oil cooled, like a Porsche or IO360 Lyc. Things have changed in bikes but I found my Suzuki GS1100 would buzz my hands to sleep, but that was 20 years ago. All the bikes, big air-cooled twins and I4's have all improved. It comes down to style, if you like to Buzzz or Thump. I like both, they each have their place.



pierre smith : "Secondly, if you ever install that shake-'n-bake WW1 Harley engine in any airplane, double the size of the called-for rivets and definitely add a BRS parachute! I have many, many miles on Harley's and Gold wings.....no comparison and still you see guys shelling out over $20,000 for a shaker Harley? No wonder they don't have an airplane! 'Nuff......

Ouch pierre, but never Nuff said and the GOLD WING is a different thing, big bulky and really a stright line open road machine. A bike like a BMW R1150RT is in a different weight class. I agree $20,000 for a scooter is crazy. On eBay you can pick up old Gold Wing's for CHEAP. Why I don't know. Probably because they made so many and they don't die? GW, H-D, BMW, rocket rice burners all good, just different.



xl1200r: "And isn't vibration one of the many concerns with the Lycs?"

No vibration is not an issue with the Lyc. If you have a reasonably balanced engine (not too important at 2,500 rpm) but more importantly the prop is balanced, vibration is a non-issue. The Dynafocal 1 of course is an excellent mount and with Lord isolatos vibration is not big deal. When talking about 2,200 to 2,700 rpm, its a pulse not a buzz. The Subaru I would concede is "smoother" kind of, sort of? A recent flight test was conducted at Van's aircraft with a Eggenfellner RV9A. The observation was made that is was different than a Lyc, not less, not objectionable, but it was a different experience (sound/vibration). It had a noticeable characteristic just like the Lycoming had as its vibration and noise character. There are always vibrations; its just a matter of what kind. In little planes (an motorcycles) you have the engine right at your feet, so its hard to isolate all the vibration.

Like a H-D motorcycle, a Lyc has sweet spots. I found my RV-4 with a O320 and Hartzell was real smooth at 2,450 and 2,750 rpm (yes it was tweaked intentionally to be a little over 2,700). It also went thru some vib mode as I slowed down and RPM went thru a "rumble" somewhere in the 2100's range.


I guess that is where the Lycoming superiority comes from, they are designed to Chug along and not give bursts of power, so the design can be optimized for this mission. A large bore, low RPM engine lends itself to this chug along mission, with the added benifit you can avoid a gear box or reduction drive belt. Less is more. On the other hand if pushed, like the NHRA Pro Stock Motorcycles, the chug chug can roar. When air cooled aircraft engines are no longer winning Reno, Sun-N-Fun, Airventure Cup, Copper State Dash and other races, I will pay attention.

 

[Mike S]

Racing tidbits

The Mazda 13b, which displaced 1308cc, had to run against larger engines, 2 litre IIRC.

The Suzuki and Kawai bikes are not allowed to run modern heads/valve trains without also having a displacement penalty against the Harleys, and the Hogs are not held to the same limits.

Apples dont always equal apples.

That said, I think the Lyc is still the winner in the avaition field---------it is hard to beat something that was purpose designed for a specific task, and then refined over decades.

Now if you want to try powering a bike with an o-360, direct drive of course, and then compare it to a factory model of the same cycle with the original engine/trans, my $$$ would be on the stock setup.

Mike

 

[xl1200r]

gmcjetpilot,

those HD race wins weren't with any run of the mill air-cooled engine. Those bikes are running liquid cooled V-ROD engines (based on the sort-of successful VR1000 of the 90's), which aren't exactly known for thier low-end grunt And like any proper race engine, they get torn down plenty over the course of a weekend.

A better comparison might be the XR750's on the flat tracks, and even a little known converted XR1000 that swept a few road races back in the 80's built by a private team.

And if anyone pays attention, a little outfit from Colorado is building some ######## (snipped by moderator...that's ONE!) fast Buells for the top speed runs on the salts.

But back on topic, I think what I found what you said is true - An HD compared to a import bike is much like a Lycoming compared to, well, anything else. You love it or hate, and each has thier own very loyal camps. And yes, I like light, simple, aircooled, long stroke (and isn't the Lyc still considered undersquare according the dimesions?) engines for these types of roles.

I have to say, my 1200cc v-twin is sure screamin and asking for more at 6000rpm

 

[rv6ejguy]

Ross,

I don't know where you're getting your BSFC data, but there is no way a automotive gasoline engine would ever do 0.35lb/hph (212g/kWh) at full load, leave alone part load cruise.

Running at stoich or at best power, a gasoline engine will be lucky to be better than 0.43/261 at any point on the WOT curve. It will only get worse than this as load is reduced.

You will need a diesel engine to achieve anything less than 0.35/212 and some will do nearer 0.325/197 at optimal speeds.

I would be surprised if a homogeneous lean-burn engine would achieve better than 0.41/250 at any point and a stratified charge GDI engine will likely be no better.

FWIW, this data is from my decade and a half of developing and calibrating gasoline engines, so whilst it's from memory, it's not too far from reality.

Andrew

I dug up some references from my pile at home:

2006 SAE World Congress "Turbocharged GDI engines currently in development are showing BSFC equivalent to diesels".

Lexus high output 3.5L V6 SFC 2000-3400 rpm .408. Toyota Motor Company. (306 hp)

New GM 3.6L VVT V6 GDI, 11.3 CR BSFC .372 2200 rpm. GM Powertrain. For 2008 model year. (267hp)

Elimination of the throttle plate as in the new BMWs shows a 15% decrease in BSFC at typical 160 km/hr. cruise conditions. (Germany I assume) Naturally this has lower gains as engine load is increased as in an aircraft application.

Jess Meyers (VAF contributor) published in AE Vol. 2 about Superflow Dyno testing on an EFI equipped SBC and achieving .34 BSFC. This was about 10 years ago.

The norm for the top Japanese engines (Toyota, Subaru) for which SFC numbers are available 10-15 years ago was in the .43-.46 range with one Honda model reportedly better than .39. Obviously recent developments would seem to point that .34-.365 is just around the corner if they are comparable to current light auto diesels.

As a sidenote there is currently at least one promising new modern auto engine conversion being prepared to compete with the IO-540 class of engines. The basic layout suggests it will be up to 50 lbs. lighter and offer comparable fuel consumption and power.

With gearing, gains in prop efficiency can be realized making the whole package at least on par with traditional aircraft engines. I've submitted some questions to MT on probable numbers.

Interesting stuff in the future for experimental aircraft powerplants I think.

 

[Andy_RR]

Fuel consumption furphies

Ross,

I think, like a lot of people, if you see a spectacular fuel consumption number or power figure, it's too hard to resist believing it. Unfortunately, there is so much heavily optimistic data out there you really have to be a little cynical about it.

I am, because having worked developing GDI engines in the past I have first hand experience that a) it takes some effort to accurately measure fuel consumption, b) it's really hard to achieve good FC figures, leave aside spectacular ones, and c) there is so much hype out there, that any optimistic figures that come off the dyno tend to get published in an attempt to steal the limelight.

Lets have a look at some of your examples:

Firstly, the R3350 is turbo-compounded, so having two working cycles, it has a significant cycle efficiency advantage - while it's undoubtedly a great way forward, it's complicated and potentially doesn't scale well so let's dismiss this as not apples-with-apples comparison.

Your quote on the Robinson LS-6 conversion doesn't square with either the reality of IC engines, or what I found quoted here (http://www.seabee.info/seabee_engine_conversions.htm) about the LS-6 - it's more like 0.45-0.50lb/hp.h

The Lexus numbers you quote are more like reality. Again, they're giving you the best possible FC, so it only gets worse from the 0.408 they quote

The GM 3.6L GDI V6, which I know reasonably well from things I've heard around the traps, is running lean-stratified with all the toys to achieve its 0.372. Again, this will probably be the best ever figure from this engine and anywhere else in the speed-load map will be worse and as soon as you go stoich, much worse than an equivalent MPI version. Honestly, the old 3.8L pushrod V6 is a much better engine for fuel consumption in the real world.

You've said a lot about BMW engines, but so far I'm guessing they've not published any BSFC data for you to see - you certainly haven't quoted me any. The 15% you claim is from which baseline? It's quite easy to move from 0.55 to 0.47 by minimising your throttling losses - that makes 15%, but doesn't give you the spectacular FC you are looking for

Now Jess Myers claim of 0.34 leads me to another point. I don't know what an EFI-equipped SBC is, but if it runs on gasoline, I just don't believe this data. 0.34 is superlative diesel territory!!!! Why is it, that people can see these dynos spit off an absolutely ridiculous number and no-one questions it? I see this all too often, especially in the tuning industry, where superflow-type dynos are popular. Not very far from standard NA engines suddenly are producing 16Bar BMEP and 140% volumetric efficiency without a turbocharger! Clearly these power figures are rubbish! If you can't measure your power accurately, then there is no way you will be able to measure realistic BSFC!

I really think your hope of significant gasoline fuel consumption gains in the future is a folorn one. It is possible to produce class-leading gasoline fuel consumption with an air-cooled, carburettored, push-rod, two-valve engine with manual mixture control, none of which is 'modern' technology. It's all in the way you use it and the compromises you need to make.

For aviation, the real leap forward in FC will come with diesel engines, if and when. Thermodynamically, they have so much going for them, it's not funny. It's just a shame that the current products either don't capitalize on diesel's strengths or are so embryonic and lacking realistic development funds.

We can live in hope though.

A

 

[gmcjetpilot]

Shes a big bone engine

For aviation, the real leap forward in FC will come with diesel engines, if and when. Thermodynamically, they have so much going for them, it's not funny. It's just a shame that the current products either don't capitalize on diesel's strengths or are so embryonic and lacking realistic development funds. We can live in hope though. A

It's that Darn weight which is so critical to light planes which is a bummer for the Diesel. Also radiator placement, ie drag, is an issue. It does not matter if you have an efficient engine with a draggy airframe.

 

[Andy_RR]

diesels must be liquid cooled?

Who mandates that diesels must be liquid cooled?

I think an air-cooled diesel, far from being just possible, is actually the best way forward.

 

[frankh]

Indeed

A german manufacturer (at least I think its German) Deutz and Yanmar both make aircooled diesels.

Of course they weigh a metaphoric ton as well!

Frank
7a...Phase 1 complete!

 

[Walter Atkinson]

Several things to ponder on this thread so far:

1) So far, no one has yet produced a GASOLINE auto engine with a BSFC(min) as good as the .385 of the TCM and Lycoming NA engines. This includes the turbo-normalized TCM engines.

2) Valve temperature is not related to EGT. It is very closely related to CHT and that's why auto engines have less trouble with exhaust valves than aviation engines.

3) The slight roughness felt LOP in a well-balanced F:A engine is the cycle to cycle variability. As noted, this can be improved upon with better head design and better fuel vaporization. It can never be completely addressed since there is also an efective ignition-drift factor involved and you do eventually get to Idle Cutoff!

4) As a Navy Admiral once said, "Water cooling an aircraft engine makes about as much sence as air cooling a submarine engine." <VBG>

5) There is compelling evidence that the next, significant improvement in BSFC for aviation engines is going to be the ability to alter timing according to the direct measurement of thetaPP (no "mapping"). That is under developement. The engines so equipped are showing BSFC(min) values in the .37 range on 100LL and, so far, have proven impossible to make detonate at any mixture setting! We've been miserable failures at inducing detonation in these engines for the last five years--and we have tried--even on 95UL aviation fuel.

6) The TC-18 varient of the R-3350 had a TBO of 600 hours when operated ROP. It had a 3600 hr TBO when operated at approximately 50dF LOP AT THE SAME POWER. That was based on about 400 MILLION hours of flight data collected, compiled, and evaluated by American Airlines.

7) We must be careful in trying to make direct comparisons in auto and aviation applications. While the combustion process it, no doubt, the same, the application of % power is quite different. If all we required of our aircraft engines was 30% power, they might have 10,000 hour TBOs also.

8) If auto engines were better than aircraft engines for aircraft applications there would have been some successful attempts, but so far there is no wide-spread success using auto engines in aircraft. (see #4 above!) A leading test facilty in Detroit has told me that they cannot get ANY auto engine to last more than 200 hours at full power on mulit-weight oil, while they have been able to get them to almost 300 hours on single-weight oils. If we were getting 2-300 hour TBOs on Lyc and Cont. engines we would be screaming. Just ask the guys who run at the 24 Hours of Lemans how easy it is to get an auto engine to last 24 hours at the powers we ask of our aviation engines on every flight for 1500-2000 hours!

Walter

 

[rv6ejguy]

I'll make a few observations here. One, I follow all the latest developments in auto engines very closely through a number of sources. Two, as pointed out by Andy, how can we trust the numbers published? Truth is, we can't. However, I do believe the stuff that SAE publishes and I believe what friends in Europe driving the latest offerings tell me about fuel consumption.

The Valvetronic when applied to GDI would seem to be a huge advantage in keeping BSFC figures low at so called part throttle settings-typically not an efficient range for gasoline engines. This has helped to narrow the gap on diesels.

I only am the messenger here. Depending on the vintage of Superflow dyno, airflow measurement on some models was known to be inaccurate however this does not affect BSFC figures. I too find the figure of .34 for a SBC hard to believe unless they had 15.5 to 1 CR, but I wasn't there.

Diesels, well the the Deltahawk is only marginally better than the best Contis and 4 stroke diesels as pointed out are too heavy in their present form.

The SAE World Congress report this year forecasted a resurgence in GDI and a slight softening of diesel sales trends over the next few years due to the efficiency gains on new gasoline engines. This is the overall opinion from engineers from all car companies. I think you have to respect that.

BMW is pursuing both low pressure variable geometry turbocharging and turbocompounding. The former is to be released in the 2008 model years according to what I've read. I don't see a problem scaling TC technology. Cummins has been using it for several years on their DTC11-01 engine.

The Lexus combined MPFI and GDI technologies in the new 3.5. This engine demonstrates only slightly higher BSFC values even up in the 4000-4500 rpm range where it might operate in an aircraft.

Walter's comment about submarines made me laugh. Good one. I think Honda's forray into piston aircraft engines needs to be looked at closely. In their 3 year study with Continental they concluded that liquid cooling was the way to go. I don't think Honda who is one of the leading producers of engines of all types (except aircraft) and vastly experienced would have done this if it wasn't deemed better after all this study. Honda stated publicly that their design gave better BSFCs, lower noise, lighter weight and lower emission than comparable aircraft engines, probably true given their expertise.

Point one- It seems that GM has produced an engine now with lower BSFC figures and probably so has BMW who rarely releases figures like this.

Point 6- TBO is a misnomer as applied to aircraft engines. This term seems to include any parts replacements not involving crankshaft removal. Today in the auto world, we'd consider opening up the engine in any way and replacing internal parts unacceptable. I can assure you that NO R3350 EVER went 3600 hours without LOTS of parts replaced along the way. As I said, my father flew these things and a good friend here was a flight engineer on them. Popped jugs and dropped exhaust valves were routine on these things. Please share that AA data with me and what parts were replaced on the way to that 3600 hour overhaul!

Point 7 and 8- This is the oldest argument about auto engines and it holds no water today. GM and Lexus who share some of their data more readily do various 250, 400, 1200 and 1600 hour tests under WOT high rpm and other conditions which would make an aircraft engine guy faint on ALL their new engine designs. You might want to follow some of the stuff published by GM Powertrain and SAE. I don't know who your source was in Detroit but this does not align with what has been widely published. This simplistic reasoning does not transfer into the European market where cars are routinely driven at power settings between 60-100% for their entire lives and demonstrate the same sort of life we seen in North America. By the way, Rotary Airforce has used Subaru engines in their gyrocopters for over a decade and has accumulated well over 100,000 flight hours with zero mechanical engine failures to my knowledge to date. Eggenfellners conversions seem to be doing pretty well too from an engine perspective.

From personal experience building showroom stock endurance racing and all out road racing for 20 years professionally, I can tell you the thing about limited life on multigrade oils is completely incorrect. We run Mobil 1 15W50 and now 5W50 in all our engines and have NEVER had a lubrication related failure. One fellow put 25,000 miles on his Toyota 4AG SS engine over 6 years, shifting at between 7500-7700 rpm for its entire track life. The engine was pretty mint when opened up after this long term abuse.

I've run turbocharged engines producing over 200hp/L for almost a decade at up to 8000 rpm on Mobil 1 and reused the bearings for 4 seasons regularly. This was not the case using conventional single weight oils. Mobil 1 is light years ahead of traditional oils. To put this abuse and power level into an aircraft perspective, this would be about 1800hp on a IO-540. How long do you think a Lycoming or Conti would last at this equivalent power level? Aircraft engines have such low specific outputs that nothing is taxed very hard. It would be comparable to running a Viper V10 at 3000 rpm and 1/2 throttle. I have little doubt it would last 3-5000 hours to generate the nominal 200hp cruise of an IO-540. This equates to 67 hp on my Subaru conversion, hmm. I think it will last pretty much forever at 67hp, this is about 2500 rpm and 30 inches.

The notion that auto engines can't last running at something like the 4600 rpm I run my turbo Subaru at in cruise is patently wrong and outdated. Millions of auto engines world wide do it day in and day out without fragging. So for about the 6th time on this forum, I'd ask you to show me proof of this statement from a reputable source.

The point of all this is that a modern six from Toyota, Honda, GM or Subaru can do the same job as an IO-540 once fitted with a well developed redrive at a fraction of the 40K new Lycoming price. I'm putting my money where my mouth is and attempting to prove it. I could be wrong but I don't think so.

 

[gmcjetpilot]

I know

gmcjetpilot,

those HD race wins weren't with any run of the mill air-cooled engine. Those bikes are running liquid cooled V-ROD engines (based on the sort-of successful VR1000 of the 90's), which aren't exactly known for thier low-end grunt And like any proper race engine, they get torn down plenty over the course of a weekend.

I have to say, my 1200cc v-twin is sure scream-in and asking for more at 6000rpm

I have no delusions that the NHRA Pro Stock bikes have very special engines. My comments just to illustrate, the high rev many little pistons, verses, the two big piston approach. The V-rod is 1200cc v-twin, was introduced 2001 and still is in production. Yes it is water cooled, OHC and fuel injected. Yes I agree any PUSH ROD engine is limited practically to 6,000 rpm. However in a 2,700 rpm airplane engine that's not much of an issue.

If I was street racing motor cycles I would not have a H-D I would have a Suzuki GSX1300R, Hayabusa or something like that. Clearly the Japanese crotch rockets are faster off the shelf.

 

[David-aviator]

Several things to ponder on this thread so far:............
Walter

1) So far, no one has yet produced a GASOLINE auto engine with a BSFC(min) as good as the .385 of the TCM and Lycoming NA engines. This includes the turbo-normalized TCM engines.
Even Lycoming won't claim that figure. At least not with regard to the IO-360-C1C in the PA-28R-200. 75% power requires 10.15 gph which is a BSFC of .405. At 55% (8gph) it is .435 which is the number I've always used in trying to determine Lycoming HP.

4) As a Navy Admiral once said, "Water cooling an aircraft engine makes about as much sence as air cooling a submarine engine." <VBG>
The Admiral drinks sea water. The best of the best WWII fighters were liquid cooled. Unfortunately, the Navy had none of them, maybe that's why he said what he said.

6) The TC-18 varient of the R-3350 had a TBO of 600 hours when operated ROP. It had a 3600 hr TBO when operated at approximately 50dF LOP AT THE SAME POWER. That was based on about 400 MILLION hours of flight data collected, compiled, and evaluated by American Airlines.
Very interesting. My experience with the R-4360 (big brother of the 3350) was awful, I almost quit flying it was so bad having been assigned to a machine with it out of the F-86. At least one engine blew up or had to be shut down every 4th flight. ROP, LOP, hogwash, it would not have made a bit of difference - there simply were too many moving parts - something was bound to fail sooner than later and it always did.
7) We must be careful in trying to make direct comparisons in auto and aviation applications. While the combustion process it, no doubt, the same, the application of % power is quite different. If all we required of our aircraft engines was 30% power, they might have 10,000 hour TBOs also.
You have not read the report of a Subaru boxer engine auto running for some 19 days at an average speed of over 100 mph. It is a matter of record. The race was in Arizona.

8) If auto engines were better than aircraft engines for aircraft applications there would have been some successful attempts, but so far there is no wide-spread success using auto engines in aircraft.
More hogwash. You've been drinking sea water with the Admiral. The Subaru is making an ever wider ripple on the pond.

dd

 

[Kevin Horton]

8) If auto engines were better than aircraft engines for aircraft applications there would have been some successful attempts, but so far there is no wide-spread success using auto engines in aircraft.
More hogwash. You've been drinking sea water with the Admiral. The Subaru is making an ever wider ripple on the pond.

The Subaru certainly is interesting. The core engine appears to be very durable. The ancilliary systems are probably the weak link (i.e. reduction drive, cooling system, fuel delivery system, etc.). The market isn't big enough to fund very much engineering or testing of those systems, so the early adopters are doing the developmental testing for the vendors. It is often said that you learn more from a failure or problem than from a successful test. The good news is that the Subaru guys are learning more each year.

It will probably be several years before anyone is selling a Subaru conversion that offers total system reliablity, weight and performance that match a Lycoming. To anyone who says we are already there, I ask: if this is true, why is the major vendor still making major design changes?

 

[rv6ejguy]

The Subaru certainly is interesting. The core engine appears to be very durable. The ancilliary systems are probably the weak link (i.e. reduction drive, cooling system, fuel delivery system, etc.). The market isn't big enough to fund very much engineering or testing of those systems, so the early adopters are doing the developmental testing for the vendors. It is often said that you learn more from a failure or problem than from a successful test. The good news is that the Subaru guys are learning more each year.

It will probably be several years before anyone is selling a Subaru conversion that offers total system reliablity, weight and performance that match a Lycoming. To anyone who says we are already there, I ask: if this is true, why is the major vendor still making major design changes?

As you rightly point out, small companies, small budgets, slow progress in development. Still, after a relatively short time, Jan is making a $2M dent in Lycoming sales every year now. Lycoming is still making changes to crankshafts after 40 years! Textron has a somewhat larger R&D budget.

As David pointed out, the wave only gets bigger every day.

On the R3350, some sources were saying TWA had 10 in flight shutdowns per DAY in commercial operation. BATCAT sources did not have kind things to say about the reliability of R3350s either. I've contacted some friends who flew and worked on these things so Ill soon have the real answer here.

 

[SteinAir]

You have not read the report of a Subaru boxer engine auto running for some 19 days at an average speed of over 100 mph. It is a matter of record. The race was in Arizona.
dd

Ok, so I've read and seen this "report" listed MANY times here and on other forums. I'm quite surprised you'd use something like that as a measurement of reliability. Here's why:

100mph x 24hrs = 2400 miles/day x 19 days = 45600 miles or 456hrs.

I'm having a hard time figuring out why any rational person would be overly impressed or remotely excited by that figure. If that's something you're pointing to as a testament of reliability and you'd be impressed getting around 400 hrs out of your engine then GO FOR IT!

Ok, not trying to be nasty. I am open minded enough and am glad that people like EJguy are working on alternatives. It's just once again that people on both sides make such ridiculous statements and comparisions that it's crazy!!! Go put an engine on your plane (of any sort) and go fly - quit debating it. Actions speak louder than words and I respect those who are walking the walk....not just talking some nonsensical talk.

Cheers (and I mean it),
Stein

 

[David-aviator]

Ok, not trying to be nasty. I am open minded enough and am glad that people like EJguy are working on alternatives. It's just once again that people on both sides make such ridiculous statements and comparisions that it's crazy!!! Go put an engine on your plane (of any sort) and go fly - quit debating it. Actions speak louder than words and I respect those who are walking the walk....not just talking some nonsensical talk.

Cheers (and I mean it),
Stein

Stein, you must be having a bad week.

I am flying with a Subaru and although I did not invent the conversion, I have done quite a bit of flight testing of it being the first Egg H6 in an RV. I am in fact flying with the second Egg engine having wrecked an airplane in '03 trying to get a super charger to work.

Ok, 400+ hours non-stop except for refueling does not set any records but I don't think any Lycoming has done it. What it does show is that the engine is basically sound and worthy of consideration, which it is getting.

I don't bash Lycoming because I know they are good engines. But I do get a little irritated reading about how no one has had success with an auto engine or that they are too heavy or that the BSFC is no good or suggesting anyone trying something different is off their rocker (departing the Lycoming world). I hear it locally also and dismiss it without prejudice. We don't all have to pull our pants on the same way.

Actually, none of this matters.

The Cards beat the Mets tonight and I also won a Cardinal lottery to buy some left over tickets for a game next week.

David Domeier
Troy, Missouri
RV-7A N707DD
H6 Subaru
About 260 hours - and getting more confident of the engine every day.

 

[rv6ejguy]

I don't bash Lycoming because I know they are good engines. But I do get a little irritated reading about how no one has had success with an auto engine or that they are too heavy or that the BSFC is no good or suggesting anyone trying something different is off their rocker (departing the Lycoming world). I hear it locally also and dismiss it without prejudice. We don't all have to pull our pants on the same way.


David Domeier
Troy, Missouri
RV-7A N707DD
H6 Subaru
About 260 hours - and getting more confident of the engine every day.

David puts it quite well here. Every time I read this stuff that auto engines can only last putting along at 2000 rpm and 30% power levels and will never last in an airplane, it annoys me because it is simply not true. I don't know where this idea came from but I'll continue to step in and challenge anyone to produce facts to support this. In the meantime, I'll keep flying my Subaru RV6A and working on my Subaru RV10. When the 10 is flying and sorted, I'll be very interested to fly it against an IO-540 one and let the chips fall where they may. I'd like to do some cross country races with it as these sound like fun. (Do I get to go in the 320 cu. in. class?) After the -10 is done, I intend to re-prop the -6A, clean it up and show the non-believers what an auto engine can do. Anyone wanna race for pink slips?

 

[SteinAir]

That's my point....at least some of you (dd & ej, etc..) are actually DOING something with an alternative engine. For that, I like and enjoy your factual posts on your experience and installations as they relate to your performance in an actual airplane.

Debating about how they run on the ground in a car or comparing them to a 3355/4360/harley/race cars/blah..blah..blah...is just kind of stupid in my opnion. I too tire of seeing this debate in such extremes (from either side). I happen to fly behind a lyc, but that doesn't mean I personally think the alternatives are a waste of time. It just means that at this point I'm too dumb and inpatient to use anything else at the moment. I don't have the patience to fiddle, nor the expertise to tweak, so I'm one of those "bolt it on an fly" people....but like I said at least I'm open minded enough to look at alternatives and watch their natural progression. Perhaps sooner or later they'll reach a point where they'll be good match for someone like me. At the moment they aren't, but without somebody actually doing something it'll never happen. Debating SFC's, Hp, etc... are all kind of moot because until they get put into an airframe (like you said) and flown for some period of time all the other stuff is relatively meaningless. Like you've said, there is NO substitue for a side by side flight of a similar plane. That's where the numbers don't lie and peoples personal opinions matter little.

We're building a beautiful panel for a Egg powered RV10 right now (another for an RV7) and I'm extremely interested, curious and consider these customers friends of mine. I truly hope these planes perform (and yours) to expectations because in the end we all win!

That's my story!

Cheers,
Stein.

 

[cjensen]

The Cards beat the Mets tonight and I also won a Cardinal lottery to buy some left over tickets for a game next week.

David Domeier

OH YEAH!!!! What a game! Go Cards!!

I'm with Stein on this one. I truly appreciate all the work that is going in to researching the alternative engines, and I hope they will be the norm one of these days. I've decided that I like watching others do the R&D, and will be going with a traditional engine.

This has been a great thread!!

 

[rv6ejguy]

Yes, the important point is these are alternatives to the Lycoming which will interest some people and not others. For those who prefer the Lyco, they will be there for a long time to come no matter how successful alternatives are.

Refinement continues on alternatives to reduce weight, increase speed and reduce fuel consumption. In the future, more flight data will come forth which is always interesting.

In the meantime, enjoy the RV flying experience with whatever you mount up front. Isn't this the fun part?

 

[gmcjetpilot]

Resale superiority

Yes, the important point is these are alternatives to the Lycoming which will interest some people and not others. For those who prefer the Lyco, they will be there for a long time to come no matter how successful alternatives are.

Refinement continues on alternatives to reduce weight, increase speed and reduce fuel consumption. In the future, more flight data will come forth which is always interesting.

In the meantime, enjoy the RV flying experience with whatever you mount up front. Isn't this the fun part?

You are absolutly right I think it would be cool to come up with an alternate engine that you created and tweaked. Of course the off the shelf Eggenfellener is anti-individual innovation. The Rotary guys and Real World Solution have come closer to the pioneering spirit. Of course rv6ejguy and other's have taken the Subaru platform to new heights (pun intended ).

The real KEY here is the market will tell us what "Superior" is. When the better mouse trap comes along it will be superior by the market.

Two

auctions in the last week have exposed the "Superior" aspect of Lycoming, Case one, a nice Velocity, 4 place, fiberglass, long-EZ type configuration with a Subaru, did not sell. The highest bid was a third of what another plane, same type sold for with a Lyc at about the same time.

The second is a current auction for a RV-6. What's a nice RV-6 sell for? $60,000? Nope this one has a buy now price of $37,500? It's a "Chevy" powered RV-6. Auction is going for another day. Current high bid as of now is less than $16,000. Another interesting "tell", it only has 120 hours on it?

My point is custom experimental engine installations are cool but the market still calls the shots, especially with resale. Now if the custom engine installation is by rv6ejguy or it's a "Powersport" Rotary set-up, that's different. Builders that do custom engine installations don't march to the drum beat of a Lycoming lope. Viva La Difference

 

[Walter Atkinson]

1) The 4360 was no where near the quality of enigne that the TC-18 version of the 3350 was.

2) The durability of the 3350 was widely varying, depending on how it was run. Some had dismal service while others (like AA) had absolutely wonderful service out of it. The AA experience was actually amazing. I know Captain John Miller (age 100 and still quite sharp--he flew his Bonanza into OSH at age 98--SOLO) who flew 80,000 hours behind the TC-18 and claims he never shut one down. (He had 20,000 hours flying them four at a time.)

3) The best of the best fighters being water-cooled? Yep. Most combat P-51 enignes were changed at 100 hours. Great TBO, huh? About the best you can hope for out of a P-51 engine, babying it, is 600 hours. That's not a stellar record. Let's just remember why it was considered a greeat fighter... it wasn't the engine's service record.

4) An IO-360 Lyc has a BSFC(min) of approximately .39. The mixtures mentioned with the BSFC above that number are ROP mixtures. BSFC(min)--the measure of the engine's efficienc--is NEVER found at a ROP setting. BSFC(min) is always in the neighborhood of 40dF LOP. For example, takeoff BSFC is in the nieghborhood of .68 to .72, depending on several factors. That's not where you measure the BSFC!

5) The Subaru. At under 500 hours, that's not a great claim of longevity. Was it MAX POWER? I doubt that. Many of the Lyc. and TCM engines are rated to run to TBO at max rated power.

The auto industry is doing some really good things, but let's not get too carried away when comparing them to aviation engines. They have a long way to go.

Walter

 

[David-aviator]

4) An IO-360 Lyc has a BSFC(min) of approximately .39. The mixtures mentioned with the BSFC above that number are ROP mixtures. BSFC(min)--the measure of the engine's efficienc--is NEVER found at a ROP setting. BSFC(min) is always in the neighborhood of 40dF LOP. For example, takeoff BSFC is in the nieghborhood of .68 to .72, depending on several factors. That's not where you measure the BSFC!

Walter

Well if the engine needs fuel to cool itself it ought to be factored into BSFC. Lycoming procedure calls for full rich up to 5000' or at more than 75% power. That sort of blows a BSFC (min) number out of the water. If the full rich BSFC were factored into the total flight efficiency of the engine, it would be close to .435 not .390.

Fuel distribution is so uneven with these engines, I don't see how a LOP procedure can work. Two cylinders might be just fine while the other 2 are starved of fuel (or too rich). In theory it might work, but not in the real world. Is LOP even recommended by Lycoming?

My last 0360 had CHT and EGT probes on each cylinder and temperatures were never the same from cylinder to cylinder. With all that information bouncing on the screen, I still found leaning until it rumbled and rich until smooth worked just fine. It may have been ROP or LOP, I don't know, but it was running smooth. You could call it running ROR ( rich of rumble).

dd

 

[rv969wf]

Hmmmmmmmm......

To date I have seen 129 replies in this thread and I have not said dodoooo so here I go. Number One, You must meet the cooling needs that the engine needs and paying attention to much detail with how the air cools an aircooled engine is a must!!!! I do not ever have to run rich to cool the darn engine in climb or hot weather 100F days... Mostly because of cooling modifications. Climbout cruise I run 100F rich of peak at 24" map and 2,500rpm with CHT"S in the low 300F degree range and I burn very little fuel. Oil temp 185F degrees all the time.....Many mods done to the cooling system and on the engine so this might not apply for everyone. YES it can be done, been there done it with 8 years of testing on my RV-6. BTW I'm running 10:50 compression ratio pistons to boot and slick mags, no electronic. Good luck to everyone with this topic. Anyone interested in how I run cool engine temps with not much fuel running through the engine feel free to ask.

 

[rv6ejguy]

2) The durability of the 3350 was widely varying, depending on how it was run. Some had dismal service while others (like AA) had absolutely wonderful service out of it. The AA experience was actually amazing. I know Captain John Miller (age 100 and still quite sharp--he flew his Bonanza into OSH at age 98--SOLO) who flew 80,000 hours behind the TC-18 and claims he never shut one down. (He had 20,000 hours flying them four at a time.)

3) The best of the best fighters being water-cooled? Yep. Most combat P-51 enignes were changed at 100 hours. Great TBO, huh? About the best you can hope for out of a P-51 engine, babying it, is 600 hours. That's not a stellar record. Let's just remember why it was considered a greeat fighter... it wasn't the engine's service record.

4) An IO-360 Lyc has a BSFC(min) of approximately .39. The mixtures mentioned with the BSFC above that number are ROP mixtures. BSFC(min)--the measure of the engine's efficienc--is NEVER found at a ROP setting. BSFC(min) is always in the neighborhood of 40dF LOP. For example, takeoff BSFC is in the nieghborhood of .68 to .72, depending on several factors. That's not where you measure the BSFC!

5) The Subaru. At under 500 hours, that's not a great claim of longevity. Was it MAX POWER? I doubt that. Many of the Lyc. and TCM engines are rated to run to TBO at max rated power.

The auto industry is doing some really good things, but let's not get too carried away when comparing them to aviation engines. They have a long way to go.

Walter

My dad has 2200 hours on the Argus, 4X R3350s. In that time he had to shut one down and these were babied (low altitude, low power settings) compared to airline service. I've got calls out to some others who've flown these engines and even to the chief engineer on the two Martin Mars' up here in BC (still flying them).

I think all fighter engines in WW2 were being pulled at less than 200 hours, air and liquid cooled, assuming it lasted that long with no bullet holes in them. In Canada we had DC-4s called Northstars, these used 1760 hp Merlins in place of the radials. They were flown by the RCAF and TCA (now Air Canada). 35 mph faster than the normal DC-4. They ferried a lot of US and Canadian troops to Korea in the '50s and had excellent reliabilty but were reputed to be deafening to ride in.

BSFC can be measured at any air/fuel ratio but is generally measured on dynos at best power and best economy mixtures depending on application. On auto race engines, we generally see best power BSFC figures in the .52-.56 range. A lower cruise rpms, most stock auto engines available in the last 15 years are in the .43-.48 range WOT.

Yes, the Subaru record was run at WOT, about 6000 rpm for 17 days with 3 cars, around the clock. Much higher stresses than what would be seen in aircraft use. Many Lycos and Contis have a 5 minute max power rating and of course as soon as you start climbing, hp is falling off in atmo engines so you are taxing it even less.

Here is an excerpt from GM Powertrain on what they run their engines through if you doubt the strength of auto engines. WOT test 400 hours at 4400-6500 rpm.

Thermal test: 4000 rpm until coolant reaches 260F. Stop it. Rig drains hot coolant, they pump in 0F coolant and wait for block to reach 0F, start it, immediately got to WOT and 4400 rpm. Run it to 260F (about 11 minutes) do it again-600 to 1600 cycles!

Transmission test: WOT and go through every gear to 6200 rpm. Closed throttle to idle in 1st gear- repeat. This is one cycle. They run up to 60,000 cycles! Very hard on rings and transmissions (usually wears out 4-5 transmissions in this test).

Idle test- 2000 hours at idle to test oil flow. Oil taken to 280F.

If it can take this, running along at 4000 or so in cruise is nothing.

As we all know, plenty of aircraft engines don't make it to overhaul without being opened up, especially ones infrequently flown. Ones frequently flown seem to do much better but there is no magic here.

 

[gmcjetpilot]

Interesting

Many Lycos and Contis have a 5 minute max power rating and of course as soon as you start climbing, hp is falling off in atmo engines so you are taxing it even less.

Not my Lycoming, but I know what you're talking about. Even the B767 has a MAX power time limit. I don't think there's any doubt the modern auto engine have earned respect from a reliability stand point. My Acura/Honda has 225,000 on it. Still there's no question a Lycoming's (with out a t/o limitation) can fly @ 100% all day as long as temps/pressures are green.

 

[Andy_RR]

which is best?

I think this thread could go on for ever and ever. In the end, if you analyse what people expect when they choose a particular path, it's pretty easy to judge aforehand whether they are heading for disappointment or delight.

In my opinion, if you choose an auto engine conversion over a Lyclone, hoping for a huge leap forward in some particular area without any other compromises, you will certainly be disappointed.

If you are doing it to capture some incremental improvements in some areas, whilst knowingly being prepared to compromise in others, you will probably be satisfied - maybe even more than satisfied.

A

 

[David-aviator]

I think this thread could go on for ever and ever. In the end, if you analyse what people expect when they choose a particular path, it's pretty easy to judge aforehand whether they are heading for disappointment or delight.

In my opinion, if you choose an auto engine conversion over a Lyclone, hoping for a huge leap forward in some particular area without any other compromises, you will certainly be disappointed.

If you are doing it to capture some incremental improvements in some areas, whilst knowingly being prepared to compromise in others, you will probably be satisfied - maybe even more than satisfied.

A

Yes, the thread does seem to have a life of its own. Some of the posts, like mine, are not very deep, others are very informative.

If one is inclined to spend a great deal of time messing around with experimental aircraft, there is an element of curiousity which goes beyond simply wanting the best. The Egg came into my life mostly out of an urge to be doing something different. Same reason for jumping from the canard world into RV's. Both are interesting and very different.

Bottom line, there is no best choice for everyone, only best choices for individuals.

dd

 

[rv6ejguy]

In my opinion, if you choose an auto engine conversion over a Lyclone, hoping for a huge leap forward in some particular area without any other compromises, you will certainly be disappointed.

Absolutely. I'd agree that even the best auto conversion is unlikely to do anything much better than the current air cooled engines except be smoother, burn less oil and perhaps cost less (if you don't count your development time ). Performance in the air, probably not much different. For me, it is the tinker, design, fabrication, validation part that is of interest plus having something different from the masses. For others buying FF packages, it is turn the key, fly it, smooth power and possibly the difference aspect again. Hey whatever turns your prop.

 

[xl1200r]

Anybody have a link to this 6,000rpm, 19 day, 100mph average Subaru race test report?

I'd like to read it only because I know that 100mph in my car is not WOT, and it's far less than 6,000rpm (I do understand these are averages as well, hence my wanting to read the actual report).

Lots of interesting stuff in here - I'm still not convinced, but I'm a newbie so who knows

 

[rv6ejguy]

The link is now dead but the meat of it was Subaru took 3 1989 production Legacy's and under FAI supervision set a record of 100,000 km at nearly 135 mph average speed in 19 days. They only stopped for gas, tires and driver changes. Wide open the whole way. No engine problems and all 3 cars finished.

My uncle and cousin were in Italy on business last year and rented a Ford Focus (2L Zetec engine). On the Autostrada they cruised at between 180 and 200 km./hr- almost WOT. They said they were in the lower 50% as far as speed goes and were passed by hundreds of cars over three days of driving. They race karts but said it was still quite an experience. This is simply common in many European countries and especially Germany. I have several friends that cruise at 200-250+ km./hr. on the Autobahn that either live there or rented Opels, BMWs or Mercedes while on vacation. They didn't report the sides of the road littered with broken cars.

 

[Kevin Horton]

According to Wikipedia:

The original Legacy speed record was set between January 2nd and 21st, 1989, with a Japanese-spec RS sedan at the Arizona Test Center outside of Phoenix, Arizona. It broke the 100,000 km FIA World Land Endurance Record by maintaining an average speed of 138.780 mph (223.345 km/h) for 447 hours, 44 minutes and 9.887 seconds, or 18 1/2 days. Pit stops were made every two hours with a driver change and refueling, while tire changes were made at 96 hour intervals, or every 13,400 miles driven.

It is also mentioned on main Subaru web site, and the Subaru New Zealand site. I recall reading about it in a car magazine at the time. Given that the average speed includes the time for pit stops, tire changes, etc, the speed on the track must have been over 140 mph, and must have been fairly close to full throttle.

Edit - Found a bit more info. At first it looked strange that the FIA site showed the record as being held by Saab at 132 mph, but then I discovered that the Saab record was in a different class.

 

[David-aviator]

Longevity factor....

Thermal test: 4000 rpm until coolant reaches 260F. Stop it. Rig drains hot coolant, they pump in 0F coolant and wait for block to reach 0F, start it, immediately got to WOT and 4400 rpm. Run it to 260F (about 11 minutes) do it again-600 to 1600 cycles!

Transmission test: WOT and go through every gear to 6200 rpm. Closed throttle to idle in 1st gear- repeat. This is one cycle. They run up to 60,000 cycles! Very hard on rings and transmissions (usually wears out 4-5 transmissions in this test).

Idle test- 2000 hours at idle to test oil flow. Oil taken to 280F.

If it can take this, running along at 4000 or so in cruise is nothing.

As we all know, plenty of aircraft engines don't make it to overhaul without being opened up, especially ones infrequently flown. Ones frequently flown seem to do much better but there is no magic here.

I made one of my weekly round robbin local cruises this morning (before the rain moves in) looking for someone to lunch with and chat. Not much luck as one airport is closed for runway resurface and 2 others very quiet. One friend was doing some touch up interior work on a Cub and that was about it. Guess the empending weather kept pilots away from their usual haunts. I commented to a tower guy about how quiet it was and he agreed, it was unusual for a Saturday morning.

These local cruises with the H6 are at 3094 rpm (prop 1700), and usually block in with about 1.1 on the Hobbs. Fuel burn comes in at 5 to 6 gallons for such a flight.

At 3100 rpm, the H6 is loafing. Even at take off power, it turns up just 4900, red line is 6000. The early Egg H6's are derated because they are married to the original 2.5 Sub PSRU at 1.82:1. Current deliveries will be with the 2:1 PSRU. I've considered upgrading to the 2:1 drive but have decided not to as a different prop would be needed to take advantage of the ratio. It is not worth the money. The airplane typically breaks ground in 400-500' as is and at the lower rpm for all ops, the H6 should last about 2 life times.

The December EGG delivery schedule is set for 56 engines. Builders are making the leap but like getting married, nothing is for sure. So far I don't regret making the plunge.

dd

 

[rv6ejguy]

According to Wikipedia:
It is also mentioned on main Subaru web site, and the Subaru New Zealand site. I recall reading about it in a car magazine at the time. Given that the average speed includes the time for pit stops, tire changes, etc, the speed on the track must have been over 140 mph, and must have been fairly close to full throttle.

Edit - Found a bit more info. At first it looked strange that the FIA site showed the record as being held by Saab at 132 mph, but then I discovered that the Saab record was in a different class.

Thanks Kevin. I think the Subaru class record was broken last year by a MB turbo diesel- 100,000 MILES at over 145mph. Can't find that link either now.
The point being in both cases, if these engines were not up to the task to being flogged WOT at high revs, they'd frag well before a week of this abuse.

I don't really beat on my Sube, never over 4600 rpm and only 37 inches for T/O, 25-30 in cruise. Just hums along.

 

[Kevin Horton]

I spent a year living in the south of France back in the 80s, and found the performance test reports in the French car magazines quite interesting. They were very interested in fuel economy, as gas was very expensive. The performance report data included a table of fuel economy at various speeds, and the last one was always "fuel economy at full throttle". There's an oxymoron for you, but it gave a hint as to how tough some of those car engines were. I used to see 1000 cc Renault 5s doing 140 km/h (87 mph) on the highway. Hit an uphill, and they would slow to 120 km/h. 160 km/h on the downhills - I'm reasonably sure they were running wide open.

I drove a motorcycle, but I needed to rent a car a few times. I used to rent VW Polos - 1600 cc engine, four speed manual transmission, no tachometer - not expensive cars. The first time I babied it, being a bit unnerved by not having a tachometer with a manual transmission. But I saw identical cars on the highway at quite high speeds. The next time I rented one for a trip to Paris, I found that it would go all day long at 155 km/h (96 mph). I accidentally discovered on long down hill that it hit the rev limiter at 165 km/h (103 mph). I have no idea what rpm I was running at 155 mph, but it was wailing like a banshee.

I have no concerns about how tough some modern car engines are. The other parts of an automotive conversion are a question mark though. Reduction drives, cooling systems, etc.

 

[rv6ejguy]

I have no concerns about how tough some modern car engines are. The other parts of an automotive conversion are a question mark though. Reduction drives, cooling systems, etc.

My thoughts exactly. The core engines (Subaru and Wankels at least) themselves seem to be totally bulletproof if fresh stock or built correctly. Almost every incident has involved supporting systems failure- electrical, fuel, cooling, redrive etc. These are the areas where most of the development and testing is going. Slowly some concensus on system design is coming out from various sources- certainly what not to do anyway. Hopefully on some of the engine/redrive forums in the future, we'll have databases on preferred layouts and designs so that newcomers don't have to repeat all of our mistakes.

 

[xl1200r]

My significant other sent me something in an e-mail the other day that really made me think of this thread. It was a quote which reads:

"If we worked on the assumption that what is accepted as true really is true, then there would be little hope for advance."

-Wilbur Wright

 

[KTM520guy]

I started reading this thread then after a few pages my eyes glazed over and I jumped to the end. Please forgive me if anything I post has been said before. IMHO the Lyco is a very good engine for it's intended use. It has set a benchmark for hp verses weight/displacement. We accept that a 180hp o-360 weighs X and burns Y gallons per hour and that it goes Z hours before needing an overhaul. It is a very old technology design though. I think that it is very possible to engineer something to beat the lycoming in every messurable catagory. Will it happen soon? I don't think so. I do hope it happens in my lifetime. Just my .02

 

[gmcjetpilot]

Good point

My thoughts exactly. The core engines (Subaru and Wankels at least) themselves seem to be totally bulletproof if fresh stock or built correctly. Almost every incident has involved supporting systems failure- electrical, fuel, cooling, redrive etc. These are the areas where most of the development and testing is going. Slowly some consensus on system design is coming out from various sources- certainly what not to do anyway. Hopefully on some of the engine/redrive forums in the future, we'll have databases on preferred layouts and designs so that newcomers don't have to repeat all of our mistakes.

I agree except for the Bulletproof part. What does that mean? Everything has a MTBF, its just a statistic. Lycoming O-360's are known as bullet proof (if built correctly).

However the WHOLE propulsion system needs to be considered. It does no good to have a bullet proof engine if there are weak links. Lycoming, the founding fathers of aircraft engines knew how to minimize them. You need no electricity and ONE fuel line (no external pump) and two push pull cables (throttle and mixture) to make the Lyc run. The Mag P-leads are normally open to work. This is not a trivial thing, if it fails it fails ON.

Some one was waxing poetic about R3350 engine life? I can't speak for WWII reliability but the TBO was about 3,500 hours in its later development life. (ref. http://en.wikipedia.org/wiki/Wright_R-3350)

It seems like these "debates" get into name calling. One side says Lycs are terrible and the Lyc side says Subaru's and Wankel's are terrible. I think we can put to rest the "bottom end" or "short block" of all these engines are very strong if "built correctly". The Lyc needs to be keep cool CHT or valve life is adversely affected. The Rotary has seals and tremendous pressures in the case, foreign object damage can kill it dead. The Subaru is an amazing engine but has lots of parts, cam belts and reduction drive, no one thing, just many little things, especially when the Achilles heal of its installation on an aircraft is considered.

Should we just throw up our hands and say don't try? No but we have to be realistic and understand that less is more Lycoming has an advantage. I think that is a lesson that may be we should not re-learn. Mechanical fuel system (pump), direct drive, mechanical or electrically independant ignition and fuel delivery. I am just saying. If the ignition wire OPENS up on a mag it keeps running. Can you use a magneto, carb, mechanical FI and fuel pump on a Mazda or Subaru? May be not because of the design of the engine. I know early Mazda's had carburetor's and Tracy of RWS used Carbs on his first efforts.

Even Jet engines on a B757/767 have mechanical fuel pumps. The Belted Airpower guys went with simple systems like belt drive, Carb and points ignition. Simple and not fancy. I'm just saying its a thought. The popular engines like the Subie and Mazda may not lend themselves to the KISS method, therefore there is only so far these blocks can go in reliability. It is just reality and statistics, the more systems that can fail the more failures you will have. To make it failsafe can be counter productive to a light reliable aircraft engine. The power sport accident showed that. You better have two of everything to make it go. Most of the Subies are running one ignition? Hummmm that is where Mr. Murphy will visit.

An all new engine? Well that is not going to happen soon. Even if one was made it would not meet the price point we all want, something like 1/2 or 1/3rd of the cost of a new (clone) Lyc today. Its just not going to happen. When a New 100HP Rotax cost $17,000, the Lyc 180 HP price seems quite reasonable.

 

[gmcjetpilot]

Older design not old technology, everything is old

I started reading this thread then after a few pages my eyes glazed over and I jumped to the end. Please forgive me if anything I post has been said before. IMHO the Lyco is a very good engine for it's intended use. It has set a benchmark for hp verses weight/displacement. We accept that a 180hp o-360 weighs X and burns Y gallons per hour and that it goes Z hours before needing an overhaul. It is a very old technology design though. I think that it is very possible to engineer something to beat the lycoming in every measurable category. Will it happen soon? I don't think so. I do hope it happens in my lifetime. Just my .02

Well its an older design but I disagree that the technology is OLD.

The engine Lyc engine as we know it was developed in 1955/57. The only engine that can claim to be new is the Wankel, but really it is just different. Actually the Wankel is not even new technology. The Wankel was first developed in the 1950's by Dr Wankel and went into production in the 1960's. It's neither a new design or new technology.

Look the Lycoming design has been stable for a few decades, but there have been improvements, the latest being the Roller Cam Tappets. Many of the other changes have been external, but never the less it has evolved.

BUT what has changed? New materials? No. New concept in the idea of a crank, rods, piston, rings, cylinders, valve train? No everything we have to day has been around since at least the 1920's.

What about new technology like OH cams and multi valves? It's been around since the early 1900's, and it would just make a Lyc wider, heavier and add a chain or belt drive. Push Rod engines are perfect below 6000 RPM.

My point is don't get design and technology mixed up. There is NO new technology in the last 80 years. Most of the elements we now know have been around for 100 years. Things like materials, blowers, OH cams, water cooling, fuel injection, on and on are still the same. Fuel injection (mechanical) is one of the new technologies and became wide spread in the 1950's.

The only real NEW things are electronics, electronic ignition and fuel injection. Would this make the Lyc better? Yes it does, about 4%-8%, max. In a car it has been a breakthrough in efficiency and lower emissions. The big differnce is a plane engine needs to chug along at one power setting, be small, light and reliable. The Lyc is very superior in almost every respect to these criteria. May be it is the best we can get with the Otto cycle engine?

We need a whole NEW breakthrough, but there is NOTHING new under the sun in engine technology, it is ALL old, even the Subaru. The Subaru is a new design with old technology. The Wankel has its limitations in efficiency. The Lycoming is was designed intentionally, not the result of lacking technology. It was the best of the best in 1950's and it ain't changed much.

I think there is a better combustion chamber shape to be had, but this one works fine. They did make an all new head, the "angle valve" head and got 20 more HP with just a 0.20 bump in compression. Of course they got into dampened cranks and added 20-30 lbs. The old saying, no free lunch, comes to mind, but the IO360 (200HP) is pretty NEW design (I think 1962).

Yes we can do better, but I am stumped how, at least if you want a direct drive, air cooled engine. No one has suggest the NEW technology that is better. BTW The turbo Compound engines was a mechanical nightmare. We have jet engines now. Small jets are the future for business and wealthy individuals. How far down the small jets make it down the food chain remains to be seen. Probably never make sense for the individual private pilot just based on utilization. I had a perfect restored car but drove it so little I sold it. Its one thing to have a $60,000 plane sitting, but a $1.5M plane flown 150 hrs does not make sense.

Yes there are NEW designs, Indy Cars, NASCAR, land speed record holder engine designs, but its all OLD technology in new designs. You would not put an Indy engine in a plane. Airplanes are a special application and most of the metrics or paradigms of cars don't equate to planes. May be little jets are the way to go for everyone? The Innodyne has shown that is unlikely anytime soon.

 

[KTM520guy]

It's old compared to me. Lol. Recip aircraft engines do their job very well but I know we could do better. If it wasn't for the lawyers we could have a modern design engine that does everything better than the 50's vintage Lycoming we have now. I'm just sayin'.

 

[Kevin Horton]

It's old compared to me. Lol. Recip aircraft engines do their job very well but I know we could do better. If it wasn't for the lawyers we could have a modern design engine that does everything better than the 50's vintage Lycoming we have now. I'm just sayin'.

A new design engine also needs many thousands of hours of engineering to design it, and several thousands of hours of testing to figure out which parts of the design need redoing. The market is so small that these costs have to be made back on just a few engines.

Even without the lawyers, it would be very hard to make an engine that was a better aircraft engine than the Lycoming (more reliable, lighter, more fuel efficient), sell it at a lower cost, and make money to stay in business. Sure, a modern production line could manufacture the engine for very low cost. But someone has to pay for the engineering and development costs.

 

[pierre smith]

The old saying, no free lunch, comes to mind, but the IO360 (200HP) is pretty NEW design (I think 1962).

TANSTAAFL
Author Unknown - Last known printing was from Industry Week, April 1975
(Robert A. Heilien was the first person known to publish the term, "TANSTAAFL")

After the War of the Almonds, the Land of Kulumar was the richest and most powerful of all.
Its fields were bountiful and its granaries were full. Its flocks were fat and sleek. The Kulumese were proud and productive. They worked and they rejoiced in the highest standard of living known.
Sire, the Generous, surveyed all this plenty and said: "Surely a country as rich as Kulumar should provide food and housing and garments for our less fortunate. I will ask the Lawmakers to levy a tax on the workers to provide this."

And the Lawmakers, each of whom hoped one day to become Sire, levied the taxes. They then said: "Let there also be free circuses for those who do not work. And let there be soft hassocks and free food and wines for those who watch the circuses."
And the Lawmakers levied more taxes.
When the workers of Kulumar heard of the free circuses, the soft hassocks, and the food and wines, and then figured their now monstrous taxes, they said: "This is for us."
The farmers left the fields. The shepherds abandoned their flocks. The weavers laid down their shuttles. The blacksmiths cooled their forges. All the Kulumese were watching the free circuses.

Plenty turned to scarcity. No longer was there abundant food. Garments were hard to come by. The Kulumese did not even have camel chips to heat their tents.
Prices rose and rose. And the Lawmakers raised taxes again and again. (It was the only thing they knew how to do.)
Misery and gloom replaced joy and pride.

And Sire, the Generous, who was well intentioned, went to the Wise Man of the Mountain and said: "Wise One, I have tried to give the good life to my people, but they no longer want to work. Food and goods are scarce. Prices are outrageous. Taxes are even more so. Give me a solution."
And the Wise Man of the Mountain replied in Kulumese: "TANSTAAFL."
Which means: "There Ain't No Such Thing As A Free Lunch."

Regards,

 

[captainron]

American Power, Baby!

Well its an older design but I disagree that the technology is OLD.

The engine Lyc engine as we know it was developed in 1955/57.

Push Rod engines are perfect below 6000 RPM.

Amen to that, George. The Chevy small block V8 was developed at the same time as the Lycoming, and is still desireable and still in use today and still blowing the doors off more modern designs. Hard to argue with a good design just because it's been around for awhile. Good design IS the very reason it has lasted this long!
One of my cars is an '02 Chevy Maliibu with the V6 derivative of the "old" small block. While cars such as these get blasted in the auto press for still using such "low tech" engines, I would ask you to show me a really superior design for this type of use.
At 75 miles per hour, this engine is turning 2100 RPM. I cannot drive at 2500 RPM on public roads and remain out of jail! And how many of you out there think I need an overhead cam, or even dual OHC engine to power this car?
Can you show me any better design than to place the camshaft in the area between the cylinders, close to the crankshaft and driven by a short metal chain or gears? Talk about compact! How many think I need more than two valves per cylinder?
Aircraft engines are not high performance engines. You wouldn't want them to be performance engines. These are, for lack of a better description, stationary power plants, the kind that power generators and such. The fact that you can put one in a movable fun toy is a bonus! These engines are designed to run their entire life at their maxium allowable RPM, and producing their maxium rated horsepower at the same time. Engines such as these operate in a very narrow RPM range with no need to have much flexibility, to accelerate rapidly, etc.. They are lightweight, they are air-cooled they have low parts count, they are perfect for their design usage. They are direct-drive, no horsepower is lost through gear reduction, and no weight is gained through same.
All this being said, I would like to see some new design, but it would have to be many degrees better than what we have now, not just marginally better in one aspect or another. If such an engine can be produced, can be proven dead-reliable, is not made out of Unobtanium and is cost-competitive, sign me up! In the meantime, it's the lowly Lyc/clone for me.

As an aside, here is an example of American performance:

AMERICAN POWER, BABY!

? One Top Fuel dragster 500 cubic inch Hemi engine makes more horsepower
than the first 4 rows of NASCARS at the Daytona 500.
? Under full throttle, a dragster engine consumes 1-1/2 gallons of nitromethane per second; a fully loaded 747 consumes jet fuel at the same rate with 25% less energy being produced.
? A stock Dodge Hemi V8 engine cannot produce enough power to drive the
dragster's super-charger.
? With 3,000 CFM of air being rammed in by the super-charger on overdrive,
the fuel mixture is compressed into a near-solid form before ignition. Cylinders run on the verge of hydraulic lock at full throttle.
? At the stoichiometric (stoichiometry: methodology and technology by which
quantities of reactants and products in chemical reactions are determined) 1.7:1 air/fuel mixture for nitro methane, the flame front temperature measures 7,050 degrees F.
? Nitro methane burns yellow. The spectacular white flame seen above the
stacks at night is raw burning hydrogen, dissociated from atmospheric water
vapor by the searing exhaust gases.
? Dual magnetos supply 44 amps to each spark plug. This is the output of an
arc welder in each cylinder.
? Spark plug electrodes are totally consumed during a pass. After halfway,
the engine is dieseling from compression, plus the glow of exhaust valves
at 1,400 degrees F. The engine can only be shut down by cutting the fuel flow.
? If spark momentarily fails early in the run, unburned nitro builds up in the affected cylinders and then explodes with sufficient force to blow cylinder heads off the block in pieces or split the block in half.
? In order to exceed 300 mph in 4.5 seconds, dragsters must accelerate an average of over 4Gs. In order to reach 200 mph (well before half-track), the launch acceleration approaches 8Gs.
? Top Fuel dragsters reach over 300 miles per hour before you have completed reading this sentence.
? Top Fuel engines turn approximately 540 revolutions from light to light!
? Including the burnout, the engine must only survive 900 revolutions under
load.
? The redline is actually quite high at 9,500 rpm.
? Assuming all the equipment is paid off, the crew worked for free, and for
once NOTHING BLOWS UP, each run costs an estimated $1,000.00 per second.
? The current Top Fuel dragster elapsed time record is 4.441 seconds for the quarter mile (10/05/03, Tony Schumacher). The top speed record is 333.00 mph (533 km/h) as measured over the last 66? of the run (09/28/03 Doug Kalitta).

Putting all of this into perspective:

You are driving the average $140,000 Lingenfelter twin-turbo powered
Corvette Z06. Over a mile up the road, a Top Fuel dragster is staged and ready to launch down a quarter mile strip as you pass. You have the advantage of a flying start. You run the Vette hard up through the gears and blast across the starting line and past the dragster at an honest 200 mph. The tree goes green for both of you at that moment.
The dragster launches and starts after you. You keep your foot down hard, but you hear an incredibly brutal whine that sears your eardrums and within 3 seconds, the dragster catches and passes you. He beats you to the finish line, a quarter mile away from where you just passed him.
Think about it, from a standing start, the dragster had spotted you 200 mph
and not only caught, but nearly blasted you off the road when he passed you
within a mere 1,320 foot long race course.
That, folks, is ACCELERATION!
(Thanks to Bill Fortune of Nitro, West Virginia for sending in this explanation of true American POWER.)