Eggenfellner Engines - Technical Only

[Rotary10-RV]

Number of masses not the critical factor

Mike and Dan,
We have been talking about the DMF or perhaps multiple stiffness driveline would be a better discription. I know I'm preaching to the Choir here but the real point here is to move any resonant frequencies out of the "normal" range correct? We can use a stiff model or a flexible model to do that. Perhaps the rubber damping segments might be our stiff model and the spring portion of the DMF our soft model. I can understand Jan's reluctance to publish figures since he is then helping his competitors to no gain. Maybe it is a better idea to recomend that his competitors do tortional vibration tests or ignore them at their peril.
An interesting study was the BD-5 with its drive shaft system.
Google BD-5 and tortional vibration and you will find the commentary. It is a very interesting problem and shows why we cannot just assemble the parts available and hope they will work. Nice that modern computer programs can now help us without breaking the bank.
Bill Jepson

 

[mcencula]

Inertia reflected through gearbox

An interesting study was the BD-5 with its drive shaft system.
Google BD-5 and tortional vibration and you will find the commentary. It is a very interesting problem and shows why we cannot just assemble the parts available and hope they will work. Nice that modern computer programs can now help us without breaking the bank.
Bill Jepson

I've read that writeup. Very interesting.

Dan,
I didn't verify any of your figures, but did you remember to reduce the propeller inertia (as seen by the half-DMF) by the inverse square of the gearbox ratio? Err...at least I think it's the inverse square. Dang I haven't done any of this stuff in so long. That's what happens when you move from engineering into project management. The brain is slowly killed by dealing with stupid customers.

 

[Rotary10-RV]

Planetary and Jans gearsets

Mike,
I like you see the advantages of a good planetary, but Jan is correct about the bearing line speed. I'm a rotary guy so I need a greater reduction. The current thought is to run a 2.85:1 or even 3:1 reduction. The drive then in a multi pinion (planet) system comes from the planet carrier and the bonus is that the prop then turns the "right" way. The bearing research I did for a friend showed that the roller bearings that we could successfully fit inside the planets (Ford/Slawsen) were right anear the top of the safe speed range. Without pressure lubrication they were rated at around 2-300 hour life. (questionable without pressure lubrication) There were ways this could be improved on but it was shown to be true. The way the turbines get around this is to stack or double the planetaries. I've got a ground power unit in my shed at home so I can see what they are doing easily. This may be "old news" but I have a direct example so i thought I'd pass it on.
I have long conjectured that one of the other reasons for Jans configureation is so he can have a clockwise (right) rotation and therefore have a greater sellection of props. Is that correct Jan?

Bill

 

[Rotary10-RV]

Most people are waiting for someone else!

I've read that writeup. Very interesting.

<snip> Err...at least I think it's the inverse square. Dang I haven't done any of this stuff in so long. <snip>

Mike,
I think the problem is that most people have never done it!

Bill

 

[DanH]

<<the real point here is to move any resonant frequencies out of the "normal" range correct? We can use a stiff model or a flexible model to do that.>>

Correct, and either way is fine in theory. The problem is practical application.

We're using internal combustion engines with multi-throw crankshafts...can you say "flexible"? Trust me here; some of my own (limited, non-professional) background included establishing F1 and F2 for a supercharged radial, meaning an engine with a single crankthrow and a propshaft only about 7 inches long and nearly 2 inches in diameter. Even with that sort of torsional stiffness F1 is still quite low. You might be able to push all the natural frequencies above redline with your rotary; it seems Powersport did it. I dunno, no useful data here. When it comes to Wankels, I'm Sgt Shultz <g>

Trying to get all the natural frequencies below idle is impossible for several practical reasons. One of the more interesting things is what can happen with a very low spring rate and a large inertia. Go back to the link I posted to the "engine simulation" .pdf earlier in this thread. Scroll down to Fig 11 and study the third graph. It is called a "resonance hang". In the case of our PSRU systems, the engine won't accelerate through the resonant period. Doesn't only happen to lowly experimenters either. The first Rotax 582's were delivered with a very soft Goetz coupler, and if you hung a three blade Warp on it you couldn't push it up through the combination of resonance and carb thrashing <g> A slightly harder coupler fixed the problem. I have the stiffness values for both couplers somewhere in my notes because I measured them.

So, in the practical world we're stuck with tuning the system. We want F1 below idle and F2 above redline...if we can get it.

<<I can understand Jan's reluctance to publish figures since he is then helping his competitors to no gain. >>

If Jan can publish data clearly showing no significant resonant amplitude within the operating range, it will bury his competitors.

<<I didn't verify any of your figures,>>

The only thing I've computed in this thread was gyro load.

<<but did you remember to reduce the propeller inertia (as seen by the half-DMF) by the inverse square of the gearbox ratio? Err...at least I think it's the inverse square. >>

I'm at the office; no references at hand. However, if memory serves (ha!), you split the system at the gearing and multiply the fast side by the gear ratio if it is expressed as greater than 1, or multiply the slow side if your ratio is expressed as less than 1. I reserve the right to look it up when I get home <g>

 

[Geico266]

This why I was confused. I did not see anything dual about the flywheel I was looking at.

As it turns out, the fly wheel on the Subie set up I was looking at doesn't have a DMF. It is a solid "run of the mill" stock Subaru flywheel. This is why I was confused.

So the DMF was an option? What is the trade off for not installing a DMF? Why would it be optional?

 

[DanH]

Jan,
Threads drift...sorry. Can we wrap up a few points about your soft element flywheel?

Some DNF's incorporate a friction-type torque overload clutch. Is there an overload clutch in yours ?

You mentioned three springs. Are you saying it has a rising rate, soft, medium, then hard ?

If so, it has "bumper blocks" (like the arrangement in the Sachs video) to prevent coil bind of the two lower rate springs ?

 

[janeggenfellner]

I have long conjectured that one of the other reasons for Jans configureation is so he can have a clockwise (right) rotation and therefore have a greater sellection of props. Is that correct Jan?

Bill


Not for the greater selection of propellers but because we are all used to right hand turning props. Keep in mind that the criteria for this kind of drive has to be "continuous duty with medium shock loading” That eliminates the use of bearings or gears, running close to max design output.

Jan


Jan

 

[janeggenfellner]

Jan,
Threads drift...sorry. Can we wrap up a few points about your soft element flywheel?

Some DNF's incorporate a friction-type torque overload clutch. Is there an overload clutch in yours ?

You mentioned three springs. Are you saying it has a rising rate, soft, medium, then hard ?

If so, it has "bumper blocks" (like the arrangement in the Sachs video) to prevent coil bind of the two lower rate springs ?


The torsion-damping flywheel was not originally used on the 4 cylinder engines. Yes, our system has a soft, medium then hard rate and also uses the bumper blocks.

Jan

 

[DanH]

<<Yes, our system has a soft, medium then hard rate and also uses the bumper blocks.>>

Got it, thanks.

Does it have a torque overload clutch? (I'm not suggesting it needs one)

In rough terms, how many degrees of rotation are available from the unloaded position to max angular deflection, ie, against the bumper blocks? (I suspect this may be one fundamental reason the OEM's developed DMFs. More is good. The Sachs video shows nearly 45 degrees, but you can't always trust marketing videos, thus my question.)

One last question and I'm done with this part of the system. Does it incorporate any form of true damping? I'm using the word "damping" in the strictly technical sense; springs are not dampers. (I suspect it does not, but I hate unknowns. Again, at the moment there is no reason to believe the system needs damping beyond that provided by ordinary bearing friction and oil viscosity.)

 

[DanH]

Mike,

I said: <<I'm at the office; no references at hand. However, if memory serves (ha!), you split the system at the gearing and multiply the fast side by the gear ratio if it is expressed as greater than 1, or multiply the slow side if your ratio is expressed as less than 1. I reserve the right to look it up when I get home>>

....and I did so at lunch today.

Den Hartog says the fast side is multiplied by ratio^2 for use in the usual equations. I had a Holzer table stuck in my mind from recent study. The angular amplitude value (col 3) for the driven gear inertia is multiplied by ratio alone.

 

[mcencula]

Mike,

<snip>

Den Hartog says the fast side is multiplied by ratio^2 for use in the usual equations. I had a Holzer table stuck in my mind from recent study. The angular amplitude value (col 3) for the driven gear inertia is multiplied by ratio alone.

It's nice to know my brain isn't totally fried yet.

 

[janeggenfellner]

Does it have a torque overload clutch? (I'm not suggesting it needs one)

No clutch

In rough terms, how many degrees of rotation are available from the unloaded position to max angular deflection, ie, against the bumper blocks? (I suspect this may be one fundamental reason the OEM's developed DMFs. More is good. The Sachs video shows nearly 45 degrees, but you can't always trust marketing videos, thus my question.)

40 degrees

One last question and I'm done with this part of the system. Does it incorporate any form of true damping? I'm using the word "damping" in the strictly technical sense; springs are not dampers. (I suspect it does not, but I hate unknowns. Again, at the moment there is no reason to believe the system needs damping beyond that provided by ordinary bearing friction and oil viscosity.)

I would consider the 20 lb flywheel, spinning at engine rpm (2.02 x prop) to provide damping.

Jan

 

[mcencula]

No damping

No clutch
I would consider the 20 lb flywheel, spinning at engine rpm (2.02 x prop) to provide damping.

Dan, It doesn't sound like there is any damping (i.e. there is no device that converts any portion of the kinetic energy into heat such as a friction slip clutch or hydraulic damper).

 

[mcencula]

Questions

Jan,

Speaking for myself, I've been wishing for more detailed descriptions and background on some of the questions posed here. In light of some of the brief responses, it occurred to me that perhaps we're asking the wrong questions here or questions that you may not be able or willing to answer. So, to get to the crux of the matter:

1. Were detailed calculations made and empirical data taken in the areas of component sizing, inertia, stress, resonance, engine output torque, impulse, NVH, etc., etc. during the design and testing of the system?
2. If yes, are you willing to share them?

Thanks,

Mike

 

[DanH]

<<Dan, It doesn't sound like there is any damping >>

No it doesn't, but I'm thinking he can get reasonable vibratory amplitudes without it. Telemetry would tell the tale.

 

[janeggenfellner]

Dan, It doesn't sound like there is any damping (i.e. there is no device that converts any portion of the kinetic energy into heat such as a friction slip clutch or hydraulic damper).

Just the gear oil. This is why we use gear oil, rather than engine oil. I do not believe hydraulic dampers, rubber dougnuts or clutches have a place in this system. Generating heat is not at all desirable. Come to think of it, the propeller, spinning through its fluid, is generating heat and hence providing damping So to conclude, the connection to the propeller is through the flywheel and gear drive only.

Were detailed calculations made and empirical data taken in the areas of component sizing, inertia, stress, resonance, engine output torque, impulse, NVH, etc., etc. during the design and testing of the system?

The answer to the above is yes.

If yes, are you willing to share them?

Not at all I am more than happy to share what I have shared so far. About how the parts go together, what HP the engine will produce, what kind of oil to use, the 200 hr full power testing, the destructive testing, etc. I am not sharing any design details however. Let's move to another system and let this rest by knowing that the measured stresses on our system, using strain gauges, is less than 1/2 of that on a direct drive engine.

Jan Eggenfellner

 

[DanH]

<<I do not believe hydraulic dampers, rubber donuts or clutches have a place in this system.>>

As mentioned, there's no reason to assume you must add a dedicated damper to the system. There is one vendor-supplied PSRU out there with a friction damper in parallel with a soft stiffness. Seems to work well, with zero failures as best I'm aware. I did a viscous damper in parallel with a Centaflex as a past experiment. Worked really well in the experimental sense; it cut resonant vibratory torque in half, by dynamic measurement, not guess. It was a failure in the mechanical design sense; fatigue stress was too high at some webs in the test article and thus it had a short life before showing cracks. A reduced stress re-design would have been the next logical step. However, it was merely an experiment, something added to a system which had been designed to run at acceptable stress levels without the damper....which is why I know it is possible.

Rubber doughnuts serve the exact same purpose as your flywheel springs. Modern rubber-in-compression couplers do have a very slight damping coefficient. On the flip side, your approach packages better, and offers a far higher limit on angular displacement. The sprung flywheel allows 40 degrees while popular rubber couplers max out at about 14 degrees....one reason I think your choice is very clever.

A slip clutch is a torque overload limiter. If it has a reliable coefficient of static friction it can guarantee shaft torque never exceeds a set value. Again there is no automatic reason to believe you need one. I was merely gathering the necessary information to develop a clear picture of your system.

<<Generating heat is not at all desirable.>>

A damping device only generates significant heat when the system is running at a resonant RPM. Put another way, it does it's job when necessary and does almost nothing (and generates no heat) the rest of the time. Just polishing the pins, old bean <g>

>>If yes, are you willing to share them?<< <<Not at all>>

Jan I like auto conversions....and I really think you're shooting yourself in the foot here. At this point we know enough to be sure there is nothing proprietary about your system; it is, per your own stated design philosophy, a collection of off-the-shelf automotive components, and the assemblage follows entirely conventional practice. The only proprietary item is the part numbers, and we've all studiously avoided asking about sources.

"Is this an adequate design? is the number one question. Legitimacy in science and engineering only comes through peer review.

Imagine standing in your booth at S&F. Let's say a few thousand prospective customers are standing around the booth. Someone starts asking detailed questions about your design and test methods, and you decline to answer. How many of those people will quietly shake their heads and walk away?

 

[Jconard]

About how the parts go together

How do they go together? I have an unanswered question regarding bearing retention. I think because of you reference to heat/retention that it is a press fit, but still not sure.

I am also wondering about heat generation. Can you confirm whether the head of the drive is conducted heat from the engine or internally generated. If internally generated, do you have any idea of quantity generated?

what HP the engine will produce

Well,
What horespower do the varied packages produce and how was that measured/ calculated?


the 200 hr full power testing

Which engine packages have performed this test, and with which drives, and which props? For example has this test been run at current boost levels with the RV10 package? Which turbo was used, and which prop? Did you do the test with all 4 blades installed or 2 ?

I am not an expert, but in reading all the voluminous information here it seems that the test would be valuable and distinct with each package power level. Of course, if the drive showed no wear with the RV10 at full boost, for 200 hours with a four blade prop...well maybe that would be seen as an "ACID" test, hence validating all lesser combos.

Finally, any exploded pictures on the way so we can see what these components are that you refer to?

I doubt there is any danger of thought thievery...it would be just as easy to buy a drive and copy it if anyone wanted too. I think this is a rare opportunity for transparency. Imagine if you could point customers to a thread where a dozen or so skilled engineers had evaluated the design.

 

[janeggenfellner]

Imagine standing in your booth at S&F. Let's say a few thousand prospective customers are standing around the booth. Someone starts asking detailed questions about your design and test methods, and you decline to answer. How many of those people will quietly shake their heads and walk away?

Lets talk about the value of this. You are, I believe, a mechanical engineer. (Don't know you) I do believe in calculating some things. I also believe that many things have already been calculated. No engineer needed to select the proper bearing for an application for instance. Practical experience and some charts take care of this. I also have worked with many that could calculate all kinds of things but could not for the life of them see that the design was not sound. If you read the RV-12 pages, you find that the kit airplanes themselves never were required to do ANY testing, prior to the advent of light sport. It is even admitted that now, when testing is required, new fixtures / methods have to be invented to actually test stuff. I know why designers could get away with this. It is because we are not doing anything new. It has all been done before. I can draw an engine mount in less than one minute and it will never brake, not be heavy and won’t fatigue over 100 years. Not because I am smart, but because all the ingredients are already available, and it has been done many times before. Because of this, I believe that the most popular air show question is still valid: "How many hours do you have on it” For Light Sport engines, that are regulated in airplanes sold assembled, one acceptable FAA test procedure is to use a lead airplane. TBO is increased as the lead airplane gain flight hours on the engine. So, just because you believe in figuring it all on paper, you are wrong about what most pilots want to know. They want to see the thing tested. That is what we do; we test the reduction drive from one end to the other. We test different oils, we test for particles in the oil, we test for vibration at all RPM, we use strain gauges, we cut flywheels apart, we examine bearings, we use all the best available materials, we over design just a little, we keep all operating parameters in our favor by reducing propeller weight, keeping shafts short, use large diameter / hollow shafts rather than solid shafts, we test with heavy propellers, we test on the most powerful engine, we destroy propellers and drive-units by running them into concrete barriers. Like I said when this thread was started, I am here for general information about our engines and not an engineering debate.

Jan Eggenfellner

 

[janeggenfellner]

How do they go together? I have an unanswered question regarding bearing retention. I think because of you reference to heat/retention that it is a press fit, but still not sure.

I am also wondering about heat generation. Can you confirm whether the head of the drive is conducted heat from the engine or internally generated. If internally generated, do you have any idea of quantity generated?


Bearings are pressed onto hardened steel shafts and heat shrunk into aluminum housings. Heat is a combination of convection and self generated. We tested the drive, remote from the engine and 90% of the heat is self generated. An equal amount of cooling was required.

Well,
What horespower do the varied packages produce and how was that measured/ calculated?

We have a torque HP chart on the web site for this. We use automotive derived #'s then de-rate them about 10%. We are always producing more static thrust than an IO-360 so we are not far off.

Which engine packages have performed this test, and with which drives, and which props? For example has this test been run at current boost levels with the RV10 package? Which turbo was used, and which prop? Did you do the test with all 4 blades installed or 2 ?

I am not an expert, but in reading all the voluminous information here it seems that the test would be valuable and distinct with each package power level. Of course, if the drive showed no wear with the RV10 at full boost, for 200 hours with a four blade prop...well maybe that would be seen as an "ACID" test, hence validating all lesser combos.

Finally, any exploded pictures on the way so we can see what these components are that you refer to?

Pictures of the drive unit are on the photo album pages of the web site. Every engine, up through the years have had long duration static testing done. The RV-10 engine was tested with the 4-blade propeller. I am realizing that this is taking an hour of my day, every day, and it is too much. I will still be on here but not this much.

Jan

 

[Geico266]

we destroy propellers and drive-units by running them into concrete barriers.

Now that's what I'm talking about right there! I wanna see that! Pay Per Veiw?! I love looking at pieces parts and see how they break.

Sorry, my inner child loves to destroy things. I always wanted to be a QC guy.

Sorry for the interruption, back to your regularly scheduled thread.

 

[DanH]

<<So, just because you believe in figuring it all on paper, you are wrong about what most pilots want to know. They want to see the thing tested.>>

Ok, no problem. Let's go directly to test results. As you say, everyone wants to see that.

<<That is what we do; .....we test for vibration at all RPM, we use strain gauges...>>

Excellent. Please tell us about the vibration tests.

 

[Jconard]

So, to confirm,

The G3 drive and RV10 package was developnment tested, at full power (boost) for 200 hours with the 4 blade prop installed? Is that the photos of a test stand that were posted before?

Just so I understand, the destructive testing involved a concrete wall?

So, just because you believe in figuring it all on paper, you are wrong about what most pilots want to know. They want to see the thing tested.

I think you are correct. But they want it tested on a flying plane, typically without change or alteration for many hours. Many will accept, as a substitute, enough volume and quality of design information that it validates the design in their mind.

Actually most potential customers which I speak to want straightforward and detailed answers about the testing in terms of hours, problems, analysis, and repairs. An early failure is not such a big deal...say a turbocharger blows...what is important is that you analyse the failure, and design a fix, and are transparent about it.

I know it is time consuming, but get the details out there! If you can pass muster with these questions and the collection of engineers here, it would really put you ahead of the other vendors.

The info so far is great....lets keep filling in the blanks

 

[Darrell514]

Jan, I noticed on your site that the valve covers on some motors are blue and some are yellow. Are these different year models? And is there a selection of engine models for the different years? Also your engine mount is gold and now black, just a change of color?

Thanks Darrell

 

[Geico266]

Jan, A buddy of mine with a Subie set up has no DMF, just a flywheel. Has there been an SB to add a DMF or is it optional?

Also, I fully understand the time constraints in answering questions.

 

[DanH]

Jan has told us he does vibratory testing. I've asked for information and data about that vibratory testing. My particular interest is vibratory shaft torque, because it tells us a great many things about the probable life of the system.

Much is made of "testing at full throttle for 200 hours", or "1000 hours in the air". Both can net useful data, but neither addresses the reality of maximum component load in this sort of system. The maximum shaft and bearing loads are seen during operation within a resonant RPM range....which is rarely at full throttle or cruise throttle.

In a system configured like Jan's, the first natural frequency will be low. Thus it will match the engine firing frequency (the most powerful forcing frequency) quite low in the RPM range. When matched, vibratory torque will skyrocket. If it were not for system damping, vibratory torque would reach infinity. Since some damping always exists in reality, it does not reach infinty, but it can easily reach high enough levels to exceed fatigue stress for some component.

A realistic "dynamic multiplier" (max vibratory torque/mean torque) is around 5 for a good system, but it can easily be 50 in a bad system. In the following illustration, I've used a multiple of 5; 100 ft-lbs mean torque at 1500 RPM, resonant amplitude 500 ft-lbs.



As you can see, 200 hours at 1500 RPM would be far harder on the components than 200 hours at full throttle. This a hard physical reality. And BTW, the illustration only covers the 1st natural frequency; the 2nd is of interest too.

The questions you should ask are "What is the maximum vibratory torque?", "Where in the RPM range is it found?", and "How many hours did you run at that RPM?"

Mike, you concur?

 

[mcencula]

Game over.

<snip>



As you can see, 200 hours at 1500 RPM would be far harder on the components than 200 hours at full throttle. This a hard physical reality. And BTW, the illustration only covers the 1st natural frequency; the 2nd is of interest too.

The questions you should ask are "What is the maximum vibratory torque?", "Where in the RPM range is it found?", and "How many hours did you run at that RPM?"

Mike, you concur?

I agree wholeheartedly. This is the type of info I've been driving at for a while. Let's see some graphs, some hard data. The problem is that Jan has stated he does have such analytical data, but he will not share it. Frankly I question whether that data is actually available since he indicated:

No engineer needed to select the proper bearing for an application for instance.

...which is contradictory to his claim that detailed calculations were made and empirical data taken in the areas of component sizing, inertia, stress, resonance, engine output torque, impulse, NVH, etc., etc. during the design and testing of the system. And, when you asked about damping, Jan replied:

I would consider the 20 lb flywheel, spinning at engine rpm (2.02 x prop) to provide damping.

...which seems to indicate a lack of understanding of even the terminology.

For the benefit of non-engineers in the forum, a damper is a device that converts some of the kinetic energy of the system into a different form of energy (typically heat, but electric dampers do exist and possibly others). One very common type of damper that everyone is familiar with is the shock absorber on a car. Have you ever had a shock go bad and the car just keeps bouncing? That's because the damper has failed.

Even if such data is available, Jan has indicated that he will not share it. For these reasons, I (sadly) believe this thread is essentially dead and will result in no more useful information.

 

[DanH]

I'm going to remain hopeful. I want Jan to have every opportunity to answer this request for fundamental product information.

 

[DanH]

Larry,
<<A buddy of mine with a Subie set up has no DMF, just a flywheel.>>

To be precise, all Egg owners have "just a flywheel". Early customers got plain flywheels because the most likely un-named supplier didn't sell DMF's before a certain date, as Jan explained (thank you sir). For the later flywheel, "dual mass" is no longer a valid description as applied; the secondary mass has been removed. That's fine; the useful parts remain, specifically the spring assembly.

<<Has there been an SB to add a DMF or is it optional?>>

I'll leave the SB/option question for Jan, and just address expected effect.

Please study the previous post regarding "What is the maximum vibratory torque?" and "Where in the RPM range is it found?" In general, for a system with this configuration, a soft spring lowers natural frequencies and lowers vibratory torque in resonant periods. A hard spring (or no spring) raises natural frequencies and increases resonant vibratory torque. Based on these wide generalizations, you might be inclined to think the later flywheel with the soft spring would be a great plus for your friend. It is not that simple. The existing high torsional stiffness (K3 in another previous illustration, the transmission input shaft on your friend's system) may have placed the 2nd natural frequency above the operating range. That is a very good thing and a desirable design goal. Installing a flywheel w/soft torsional spring may move it down the RPM range, perhaps right into the full throttle area. Very undesirable indeed.

Perhaps is the operative word. Without basic frequency data or even the stiffness and inertia data for a decent model, nobody has a clue about the better choice.

 

[janeggenfellner]

I'm going to remain hopeful. I want Jan to have every opportunity to answer this request for fundamental product information.

Now, after having been called a liar in the above statements, and discussed with partners here at the company, we have decided that the information requested is for company use only. We are not willing to share testing that cost thousands of $ and countless hours to generate. We are happy to share general information but that is not where this is going.

You still have the opportunity to use this thread for what I thought it was about. Namely, discussing how our engines go together and why they work as well as they do. General information about ECU's, cooling, exhaust, reduction drives, engine mounting, etc. Is available from me. Company collected data, used to make our engines work, is not available. Like you know, it is all in the details. We are keeping the details.

Representatives from Honda discussed harmonics with their engine project with me recently. Very interesting and fun.

Jan

 

[janeggenfellner]

Jan, I noticed on your site that the valve covers on some motors are blue and some are yellow. Are these different year models? And is there a selection of engine models for the different years? Also your engine mount is gold and now black, just a change of color?

Thanks Darrell

The yellow covers are painted with engine enamel and are 2007 model engines. The blue is for 2008 and is IMRON paint. We do not use powder coat on this because it gets on the gasket flanges. The engine mounting plates were just aluminum about 15 years ago. Then we changed to a black anodize and now, with the red gearbox housing, to a gold anodize. Switching to gold made us burn up 2 starters before we realized the color tough enough that the starter would not ground properly. We now use a ground strap for it. For some reason, the black never gave us this problem, even though it also is non conductive.

The gold plate is a little lighter and all corners have a radius for better look. Everything else the same as before.

Jan

 

[janeggenfellner]

Jan, A buddy of mine with a Subie set up has no DMF, just a flywheel. Has there been an SB to add a DMF or is it optional?

The 4 cylinder engines have tested just fine without the torsion damping flywheel. However, idle will be smother and shut-down not so abrupt with it.

Jan

 

[janeggenfellner]

So, to confirm,

The G3 drive and RV10 package was developnment tested, at full power (boost) for 200 hours with the 4 blade prop installed? Is that the photos of a test stand that were posted before?

The first turbo engine was flown, by myself, for over 200 hr in my RV-6A. We limit boost to 28" on production engines. My flight testing was at 28-30" but also much of it at 36" of MAP to see what would let go. The gear oil was very clean throughout the program. I flew with 3 and 4 blade propellers. Sometimes it is frustrating to listen to those that have no idea of what it takes to flight test something for the purpose of trying to make it fail, in one way or another. It is disrespectful of those that insinuate that we are liars and don't do what we say.

Just so I understand, the destructive testing involved a concrete wall?

Yes, and a trailer. We just pull tested a carbon fiber propeller blade with a spring scale, a steel hangar door frame and a Toyota Tundra. Bucked at 1600 lb.

Actually most potential customers which I speak to want straightforward and detailed answers about the testing in terms of hours, problems, analysis, and repairs.

that is our aproach

The info so far is great....lets keep filling in the blanks

It is the blanks that make our engines what they are. We do not give those away. Detailed analyses of our parts and test procedures are company property.

Jan

 

[Jconard]

Namely, discussing how our engines go together and why they work as well as they do. General information about ECU's, cooling, exhaust, reduction drives, engine mounting, etc. Is available from me. Company collected data, used to make our engines work, is not available. Like you know, it is all in the details. We are keeping the details.

Well, I for one was hoping for a little bit more. I supporse if I wanted a discussion of why the engine works so well, your site provides that. I am still wondering about data, to support these tests.

The vibration data does not seem proprietary, if the data exists, why not put everyone's mind at ease?

I asked which particular engine and prop combinations were subjected to 200 hour continuous WOT full power testing, and you told me:

The RV-10 engine was tested with the 4-blade propeller. I am realizing that this is taking an hour of my day, every day, and it is too much. I will still be on here but not this much.

I wanted to make sure I had it right so I clarified and got this response:

The first turbo engine was flown, by myself, for over 200 hr in my RV-6A. We limit boost to 28" on production engines. My flight testing was at 28-30" but also much of it at 36" of MAP to see what would let go. The gear oil was very clean throughout the program. I flew with 3 and 4 blade propellers. Sometimes it is frustrating to listen to those that have no idea of what it takes to flight test something for the purpose of trying to make it fail, in one way or another. It is disrespectful of those that insinuate that we are liars and don't do what we say.

I did not insinuate anything, but am still trying to figure out which packages have had this 200 hour full power test, etc. Has the RV-10 been subjected to the continuous 200 hour full power test, and with which prop?

Could you describe the destructive test? Could you describe the other testing?

I will take you at your word that all of these tests have been done. I am not accusing you of making them up. But the data which is being requested would simply validate your design, and would not give it away.

Please provide the information.

 

[mcencula]

Sorry

Jan,

It wasn't my intention for you to interpret my comments as questioning your honesty.

When you replied that you did xyz analysis and testing, I believe your response was truthful in that you believe you did the testing we've been asking about and have the data we've been asking about.

However, if you were to decide to share 100% of all your data with us, I'm doubtful it would comprehensively cover the type of analysis and testing that Dan and I would expect from a product that's on the market. That's the basis of my comment doubting that the data we want is really available.

At this point, the discussion is academic since you and your team are unwilling to share what results you do have.

Please accept my sincere apology for not wording my last post more carefully.

 

[Rotary10-RV]

Propriatary information? YES.

Hey Guys, I'd say Jan has been pretty forthcomming about your questions. If you called up Ford, GM, or Toyota and asked for their test data they would laugh you out the door. I don't mean that in a hostile way either. In todays society, If you were, in your effort to, "understand what has been done", were to find someone miscalculated a rotational inertia, moment, or what ever in your quite honest effort to improve the breed, it would open up the gates to any disgruntled customer. While I KNOW that is not your motivation, nobody is going to put that info out there.
My point is that if Jan has done his homework perfectly and printed that info it would not, as Dan said "bury his competitors." It would EDUCATE them. While that is good from the stand point of the movement at large, for Jan it is at best the lack of a negitive. A zero if you will. There is absolutely no motivation to do so, and a good many reasons NOT to. We as engineers love to know all the answers. We will have to take this one on faith, though or buy an engine and test it yourself. Consumer Reports has made a good living doing that for a long time. (Hopefully honestly, but it even possible for independent testing services to have an agenda.) I am sorry to interject the real world as it exists today into the discussion, but Jan has politely avoided mentioning it. This comment has absolutely no value in the engineering discussion, but in my experience I have seen parts rejected by a hostile INTERNAL division at one place I worked because the reinforcing webs were .001 inch out of tolerence. (on a blueprint) That despite the fact that these items were 200% overdesigned to begin with. I am thankful that Jan is out there, and if it were'nt him the next guy to put out a good FWF would then become the target. Pressing the point with Jan is exactly the reverse of the reason to begin the thread to begin with.
I'm rotary oriented and got to be pretty friendly with the guy that did the newest Powersport drive. He did his PHD thesis on the vibration studies of the PowerSport rotary and drive combo. He wouldn't reveal the info to outsiders either. They make or made a good drive, but if they are still alive it is just barely. Nobody is saying you shouldn't do a full set of calculations. You do at some point have to BUILD and SELL the thing or you won't have any money for testing or building the next generation. The time at which to, "kill the engineer" is the subject of so many business arguements you can't count them. Jan has shown a willingness to address some pretty probing comments. I think we need to back off and cut the guy some slack.
Bill Jepson

 

[Geico266]

The 4 cylinder engines have tested just fine without the torsion damping flywheel. However, idle will be smother and shut-down not so abrupt with it.

Jan

Thanks Jan, I'll pass it along.

 

[janeggenfellner]

I did not insinuate anything, but am still trying to figure out which packages have had this 200 hour full power test, etc. Has the RV-10 been subjected to the continuous 200 hour full power test, and with which prop?

There are no RV-10's using our engine with 200 hr. I repeat: The first turbo engine was flown, by myself, for over 200 hr in my RV-6A. We limit boost to 28" on production engines. My flight testing was at 28-30" but also much of it at 36" of MAP to see what would let go. The gear oil was very clean throughout the program. I flew with 3 and 4 blade propellers.

The engine in my RV-6A is the same engine as the RV-10 engine.

Jan

 

[DanH]

Bill,
I'm gonna stand on this statement:

The questions you should ask (of any potential alternative engine vendor) are

(1) "What is the maximum vibratory torque?"

(2) "Where in the RPM range is it found?"

(3) "How many hours did you run at that RPM?"

They address results, not how they they came to be. The only thing they tell your competitor is how high you've set the bar.

Mike,
You merely voiced what a lot of other folks are thinking.

 

[janeggenfellner]

Jan has shown a willingness to address some pretty probing comments. I think we need to back off and cut the guy some slack.
Bill Jepson

It is not that I don't think I can learn from all of you. Or that I don't agree that many brains can impove a product. It is just that we have no issues in the areas being discussed. We are dealing with stuff like providing a good sealing surface for a Viton seal on stainless steel

It is true that we do not know exactly how long the springs will last in the flywheel, or if the pilot bearing will go 500 or 1000 hours. But we know about these tiny issues and will keep an eye on them.

Also, I would rather get an hour running a test than typing.

Jan

 

[Rotary10-RV]

It is just that we have no issues in the areas being discussed. We are dealing with stuff like providing a good sealing surface for a Viton seal on stainless steel
<snip>
Now Jan, That I can help you with! PM if interested. I work in the vacuum industry and good finishes are an absolute must!
Also, I would rather get an hour running a test than typing.

Amen to that.
Jan

Bill Jepson

 

[janeggenfellner]

Here is an email with GENERAL results from the latest engine / propeller / reduction drive testing. The details are not available.

Good Morning Jan, we performed last November a vibration test with a new gear box and turbo engine and even with a new gear box the dynamic loads are very low for the
propeller compared to a direct drive engine.

With best regards,
MT-Propeller Entwicklung GmbH

Martin Albrecht
Vice President / General Manager

 

[janeggenfellner]

It is just that we have no issues in the areas being discussed. We are dealing with stuff like providing a good sealing surface for a Viton seal on stainless steel
<snip>
Now Jan, That I can help you with! PM if interested. I work in the vacuum industry and good finishes are an absolute must!
Also, I would rather get an hour running a test than typing.

Amen to that.
Jan


Yes, we are learning this. The front seal is riding on stainless to avoid rust over the years. The steel is soft and can get scratched between the manufacturing process and installation. I hope we cured it by taping each seal surface for protection, until installation. Also, we went from a 10 mm wide to a 12 mm wide seal and so far all is good.

Jan

 

[DanH]

<<That is what we do; .....we test for vibration at all RPM, we use strain gauges...>>

Jan, for the sake of clarity, let's set aside my three-question request for the results of your tests...at least for now. You always have the option of publishing the data later.

Returning to the quote above, a single specific question please, and "yes or "no" is fine: Did you apply a strain gauge to the propshaft and record vibratory torque?

 

[David-aviator]

....Imagine standing in your booth at S&F. Let's say a few thousand prospective customers are standing around the booth. Someone starts asking detailed questions about your design and test methods, and you decline to answer. How many of those people will quietly shake their heads and walk away?

In all fairness with regard to the discussion, if such questions were posed to Lycoming or Continental at SNF concerning crank shaft recalls there would be no answers either. Jan is not a professional engineer and you professional engineers know it.

 

[Mike S]

In all fairness with regard to the discussion, if such questions were posed to Lycoming or Continental at SNF concerning crank shaft recalls there would be no answers either. Jan is not a professional engineer and you professional engineers know it.

I have to agree.

This thread has stayed on course for the better part of 8 pages, before someone threw out a zinger----which was later apologized for---but it is starting to slowly start down the same old slippery slope.

Jan has every right to keep certain info to himself. I believe the legal term is "intellectual property".

I for one, am amazed at the amount of info he has provided, not sure if I would have been as free with these hard earned "trade secrets" if I were in his shoes.

Jan, for myself and others who have been following this thread with interest, I want to thank you for being so patient, open, and informative.

 

[Sam Buchanan]

I have to agree.

This thread has stayed on course for the better part of 8 pages, before someone threw out a zinger----which was later apologized for---but it is starting to slowly start down the same old slippery slope.

Jan has every right to keep certain info to himself. I believe the legal term is "intellectual property".

I for one, am amazed at the amount of info he has provided, not sure if I would have been as free with these hard earned "trade secrets" if I were in his shoes.

Jan, for myself and others who have been following this thread with interest, I want to thank you for being so patient, open, and informative.

Yep, as a forum moderator I am struggling with this thread. The free flow of information is good, and the conduct of all in the thread has been more or less good.

However, I see this thread as a lose-lose proposition for Eggenfellner. It is obvious he does not have the formal background of some of the posters to this thread, and I fear that regardless of whatever info he presents, it will be ripped by those with theoretical and formal engineering backgrounds. There is no way a vendor can present technical information that will satisfy all who either have a genuine interest in the product or.......an agenda to pursue.

Kahuna, I admire your willingness to moderate the thread, but I suspect we are nearing the conclusion of this discussion. Hopefully it will be closed before Doug has to step in and exercise the ultimate moderation.

This thread once again stresses the experimental nature of our aviation endeavors, and "alternate" powerplants in particular. Let the consumer be aware, and go into engine selection with eyes wide open.

 

[Mike S]

Yep, as a forum moderator I am struggling with this thread.

Yep, me too Sam.

That is what prompted me to post the above comments.

I would prefer to gently nudge, than amputate.

 

[DanH]

Whoa Nellie.....

Speaking for myself, this is not a case of a professional engineer picking on the weak. As I've repeatedly posted in the past, I do not hold an engineering degree. I do think anyone can learn the material, those contemplating a conversion should learn the material, and designers/vendors must know the material. A personal opinion.

Second, I promised tough questions when I proposed this thread. At this point I've reduced my own requests to a single question, which I hope Jan will accept.

Three, the only agenda is to shine light in the dark places. We may find gold, or we may find cockroaches, or we may find both....but I didn't set out to find just one in particular.