Alternative Engine Real World Experience?

[Steve Mills]

Check the web site (www.eggenfellneraircraft.com), and you will see that the E-6T engine is $29995, not $35,000, and that includes the turbo...the intercooler is $1900 more.

[rv6ejguy]

This thread was started by a LANCAIR guy who I assume is reviled by the high cost of engines for these aircraft and asking a legitimate question about alternatives. You fellows check the prices of engines used in the big Lancairs - $55K-$65K for a ready to run N or TSIO. That is crazy.

I've posted this before: Auto engines today are designed and routinely tested to higher standards than certified aircraft engine requirements. The FAA only requires 100 hours of full throttle, full rpm for certified engines and another 50 hours at 75-100% power, 50 hours of which are required to be at redline oil and cylinder head temperatures. Most auto engine manufacturers today do a minimum validation of 200 hours of WOT at rated hp rpm and some as much as 1200 hours. In addition to this test, they perform cold weather testing to the tune of 1000+ cycles of cold soaking the engine to 0F and immediately taking the engine to WOT and high rpm until coolant reaches 240F. While the engine is still hot, 0F coolant is pumped into the engine until the block achieves 0F and the test is repeated- over 1000 times. Additional tests often include idle testing to 2000 hours with oil temperatures of 260F+ and transmission validation where the engine is cycled from low rpm to shift point rpm at WOT while the transmission is shifted up and down for up to 1600 hours. Not just one engine is put through these tests- dozens are. Wear rates are noted and obviously failures are not acceptable before release of the design.

So, please, no more talk about auto engines being somehow inferior in design, strength or longevity to aircraft engines. I invite anyone to do the torture tests described above on a Lycoming or Continental. I'd love to see how long they'd last- if they even actually started without pre-warming.

From my article on this question: "Automotive Engines Will Not Take Continuous High Rpm Use"

"This is the most common misconception put forth by lay, anti-auto power people and is utter nonsense. They often go on to say that auto engines were designed for low rpm operation and 15-30 hp is required to cruise a car at 70 mph. This simplistic, flawed reasoning is completely unsupported by facts. When asked to supply facts to support their contention on various forums since 2003, not one person has ever done so." I'm still waiting for some facts that show premature wear or failure from running at 4500 rpm WOT. If you don't have the facts, stop sprouting this misinformation. I like the factual discussions started recently on VAF. Let's leave out the conjecture based on "feelings".

There is NO requirement that full rated power on certified engines be demonstrated for the set TBO time and no tests like this have ever been run to my knowledge nor is this recommended by Lycoming or Continental- in fact specific limits for max rpm WOT are set for many of the 6 cylinder engines, especially the turbocharged ones. It is complete nonsense to believe that one of these will run to TBO at rated power-well illustrated in the class action lawsuit filed against Lycoming concerning an alleged 10% inflight failure rate on its TIO-540-AE2A engines powering Piper Mirages. This engine has a TBO of 2000 hours however, a survey of 92 owners found that only 4.3 percent made it to 1500 hours. The average was 727 hours. 41% needed a top overhaul before 1000 hours and many needed topping at 200-300 hours. Why Lycoming sets the TBO at an unrealistic 2000 hours is puzzling when probably not one engine ever reached that without topping. If it was set at a more realistic 750 hours, owners would expect a more realistic operating cost. You work out the cost per hour with an overhaul at 700 hours and the initial price tag on an engine like this. I'll use that word statospheric again here.

Topping and cracking heads are a fairly common reality on the higher hp Lycoming and Continental sixes used in larger singles. I hear and read stories about these problems every month. People with these larger engines do wish there was something better or at least cheaper out there. I do believe you will see more and more of the large singles being fitted with LS type V8 engines in the future as the state of the art progresses. Again, I'd point people needing 300+hp to EPI's outstanding website: http://www.epi-eng.com/

This has realistic discussions on all aspects of V8 engine conversions supported by real engineering, testing and validation of every aspect.

[dtaylor]

So?? How come nobody has answered my original question?

I just asked now much time you alternative engines guys have on your machines so far.

I know all this stuff is new but still, how much flight time are we talking about? 200 hours? 300 hours? 400 hours? Anybody?

(I am not being a smartass i assure you. I really want some operating facts!)

Dave T

[rv6ejguy]

For engines in the power range suitable as a replacement for a 550-N, Bud Warren got about 700 flight hours and apparently many Ag planes got 500-1000 hours between overhauls on big block Fords. Finally one fellow who has corresponded with me from Oz has over 400 hours on an LS1 in a Pawnee used for glider towing. Another guy has a direct drive Ford V8 in an Eze and regularly waxes O-360 powered ones in races. He has over 500 hours on it I think.

http://www.alternate-airpower.com/index.html

In the lower hp conversions, many Subes have accumulated 500-1000 hours trouble free in fixed wings and high time one that I know about in a gyro is 3600 hours.

[dlomheim]

"So?? How come nobody has answered my original question"?

Wish I could reply but I'm still building after 8 years...hopefully by next fall I'll start logging some hours!

Doug Lomheim
RV-9A, 13B, FWF

[rtry9a]

The longest alternative app I know of involved Jim Mayfield's training gyroplane- I believe it had a belt drive PRSU on a Mazda 13B rotary ~2500 hrs. when the gyro was replaced. Gyroplane use is harder than most other aircraft apps- always at full power.

Tracy Crook has somewhere around 1500 hrs on his Mazda 13B powered RV4 with a planetary geared PSRU- it originally had a badly-designed Ross drive (no thrust bearing) that Tracy redesigned into his RWS box which he now markets. Several users have close to 1000 hrs on the RWS PSRU/rotary engine combo, but, because the RWS unit it is only a few years old, it will take a while to gather a TBO database. It is looking good so far.

Rotaries generally do not show much wear at 1000-1500 hrs when run with a 2-cycle oil/fuel mix. The rotary TBO is not yet known, presumed to be more than 2500 hrs if not overheated (overheating takes out o-ring seals, not catastrophic failures). I do not know of a PRSU failure with the RWS units yet- the design was improved with a minor staking pin upgrade to reduce gear movement; one short production run used a bad import ball bearing that Tracy replaced with a quality roller bearing.

The PSRU unit is rated to 300 hp, the current Mazda engines are rated 200-250hp, 300+ with a turbocharger. FWIW. they seem to be more popular with the canard crowd than with Van's (more of an experimental orientation perhaps, dont know why, as they are ideally suited to most of Vans newer planes).

[Kevin Horton]

Originally Posted by Jconard

[color="Blue"]Wrong, aircraft engines which are rated for full power are rated to run that WOT for full TBO.

I won't speak to the details of automotive engine testing, because I have no knowledge in that area. But, for aircraft engines, it is useful to review the FAR 33.49 endurance test requirements for reciprocating aircraft engines. You will note that the whole test only requires 150 hr of operation, and only a portion of that time is at rated power.

33.49 Endurance test.

(a) General. Each engine must be subjected to an endurance test that includes a total of 150 hours of operation (except as provided in paragraph (e)(1)(iii) of this section) and, depending upon the type and contemplated use of the engine, consists of one of the series of runs specified in paragraphs (b) through (e) of this section, as applicable. The runs must be made in the order found appropriate by the Administrator for the particular engine being tested. During the endurance test the engine power and the crankshaft rotational speed must be kept within ?3 percent of the rated values. During the runs at rated takeoff power and for at least 35 hours at rated maximum continuous power, one cylinder must be operated at not less than the limiting temperature, the other cylinders must be operated at a temperature not lower than 50 degrees F. below the limiting temperature, and the oil inlet temperature must be maintained within ?10 degrees F. of the limiting temperature. An engine that is equipped with a propeller shaft must be fitted for the endurance test with a propeller that thrust-loads the engine to the maximum thrust which the engine is designed to resist at each applicable operating condition specified in this section. Each accessory drive and mounting attachment must be loaded. During operation at rated takeoff power and rated maximum continuous power, the load imposed by each accessory used only for an aircraft service must be the limit load specified by the applicant for the engine drive or attachment point.

(b) Unsupercharged engines and engines incorporating a gear-driven single-speed supercharger. For engines not incorporating a supercharger and for engines incorporating a gear-driven single-speed supercharger the applicant must conduct the following runs:

(1) A 30-hour run consisting of alternate periods of 5 minutes at rated takeoff power with takeoff speed, and 5 minutes at maximum best economy cruising power or maximum recommended cruising power.

(2) A 20-hour run consisting of alternate periods of 11/2hours at rated maximum continuous power with maximum continuous speed, and1/2hour at 75 percent rated maximum continuous power and 91 percent maximum continuous speed.

(3) A 20-hour run consisting of alternate periods of 11/2hours at rated maximum continuous power with maximum continuous speed, and1/2hour at 70 percent rated maximum continuous power and 89 percent maximum continuous speed.

(4) A 20-hour run consisting of alternate periods of 11/2hours at rated maximum continuous power with maximum continuous speed, and1/2hour at 65 percent rated maximum continuous power and 87 percent maximum continuous speed.

(5) A 20-hour run consisting of alternate periods of 11/2hours at rated maximum continuous power with maximum continuous speed, and1/2hour at 60 percent rated maximum continuous power and 84.5 percent maximum continuous speed.

(6) A 20-hour run consisting of alternate periods of 11/2hours at rated maximum continuous power with maximum continuous speed, and1/2hour at 50 percent rated maximum continuous power and 79.5 percent maximum continuous speed.

(7) A 20-hour run consisting of alternate periods of 21/2hours at rated maximum continuous power with maximum continuous speed, and 21/2hours at maximum best economy cruising power or at maximum recommended cruising power.

Appendix A to FAR 33 requires the engine manufacturer to define a recommended time before overhaul for the engine, but there is no requirement that the engine be able to run at rated power for that duration. The TBO that the manufacturer chooses assumes typical operation of the engine - i.e. full power is typically only used for a short period on each flight.

[Rotary10-RV]

Originally Posted by dlomheim

"So?? How come nobody has answered my original question"?

Wish I could reply but I'm still building after 8 years...hopefully by next fall I'll start logging some hours!

Doug Lomheim
RV-9A, 13B, FWF

Doug if you are a rotary guy, and by your signiture I would assume that, you must have seen Tracy's home page. It has the hours listed on his RV-4 conversion right up front. 1650 hours. Tracy removed the older 13B engine at 800 hours. (it was an unopened junkyard engine!) He didn't wear it out, He wanted to test his newest 2.85:1 redrive and later a Renesis 2 rotor. If you were hoping for a fleet of guys to chime in with wear numbers and figures, don't hold your breath. I don't think they would want to come on this site in the first place. Way to much NIH ridicule. I have become an infrequent poster because of it. If you put together a perfectly viable auto engine alternative and it gets 1 HP less that a Lyc or weights 10 pounds more or uses .3 more GPH you are an idiot according to at least half the posters in the ALTERNATE ENGINES forum. In fact you are a hazard to the public and to the well being of all general aviation too. I tired of the "defend your life syndrome." I think there are more posters in the engine specific forums, like Fly Rotary, or the Subaru Yahoo forums. More information and way less hassle.
Bill Jepson

[rv6ejguy]

Thanks Kevin for the facts on certification requirements. I might add that since atmo aircraft engines operate at altitude, they are rarely and even then shortly not putting out rated takeoff power most of the time. WOT at 8000 feet is only around 75% depending on rpm.

My choice for an unpressurized Lancair would probably be an L92 with puts out 300hp at only 3800 rpm and 225 (75%) at only 3000 rpm. Weight would actually be less than a 550N even with PSRU, rads and coolant. I'm pretty sure this is not going to frag in a few hours running along at 3 grand. $6000

If I needed more jam and wanted to spend double, the LS7 puts out about the same numbers but would give you more power at higher rpms- 400hp at only 4600 rpm. This is a nice piece with titanium rods and intake valves and sodium filled exhaust valves. Even 4600 rpm is loafing on this engine which has a 7000 rpm redline and puts out 505hp and 470 ft./lbs. $13,000

By Golly if GM doesn't offer single plane carburetor manifolds for these engines too if you don't like EFI!

[janeggenfellner]

Was grounding the fleet for upgrade an option then? I guess I got the impression the bulletin from your company made it mandatory.

It is as mandatory as you want to make safety. All earlier drives should be replaced with the better unit.

Jan