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The No Alternative section

What they assume is that they will be able to achieve these goals while maintaining the reliability performance the same as a traditional AC engine based on the reliability performance of the machine the engine was designed for. It is a flawed assumption, but the promises usually overwhelm the desire to critically challenge them.

Not really flawed as many people you probably don't know about have shown. Here is a good example (skip to page 27 and pages 29-33): http://www.glidingclub.org.au/Documents/Airflow/Airflow 2011-3 Spring.pdf

http://www.glidingclub.org.au/members-only/aircraft/etug/

The 200 less cubic inch LS1 did this demanding job much cheaper and better with far less maintenance than the 540 Lycoming. Previous to this, a V6 Ford also did it cheaper and better, paving the way for the later V8 conversions. http://victoriancollections.net.au/items/510a18022162ef11145dba31

I could list a bunch of others but I'd be repeating myself.

Yes, not something that anyone can do but it's been done more times than most of the readership here on VAF know so it's certainly possible with the right background.
 
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rv6ejguy, I also said:

"In the end, yes, you can make an auto (or other) conversion work and we all know that. What is not known is how much resource will be burned."

What I mean is that there are very few people who are qualified to estimate how much knowledge and resource it will take so that they can really know what they are getting into from the beginning. Not that it can't be done, we know it can be done, there are plenty of examples of that.

I have a lot of respect for what you have done and continue to do, so I hope I don't come across as argumentative. I am supportive of people willing to go down the alternate power path, I just think there are a good many people who either are thinking that way, or went that way, that went in with a goal in mind, but didn't go in with visibility to the knowledge and resources it requires to succeed or if their goal was realistic. I guess my basic position on the subject is that:

1) I agree with the post that started the thread in that I think we as a group should be supportive of those that want to try to use alternative power.
2) I believe that we also probably have some responsibility to help others understand the challenges that may be in front of them, in a positive way, so they can accurately plan for how they will get (if they need to) the knowledge and resources necessary.
3) I also believe we can help people talk through why they want alternative power and whether it looks like they will achieve that goal or not. In the end, it is always their choice.

Tim
 
That sums up my thinking very well. Unfortunately when we follow point 2) it sounds like we are badmouthing alternative engines. It's not the case for me, but I can see how it would be interpreted that way.
 
My point was that VAF is not the forum to get the big picture about successful auto conversions but there is a whole world out there most folks here know little about. There are literally thousands of auto engines flying worldwide very successfully, so it's not like there are just 12 in the whole world. Thousands means lots of people have done it and found it worthwhile in some way- lower costs usually. Many of these are vendor supplied VW, Subaru, Corvair, Suzuki etc., some are one-offs. Sonex in particular has been very successful with their Aerovee offerings which power the majority of their kits.

I think there has been enough negative experiences with alternative vendor engines here and elsewhere that most RV people considering buying one before, would not now. I doubt if more than 1% of new build RV 7, 8, 9, 10 and 14s have alternative engines fitted these days. It just doesn't make sense for the majority of RV builders which have the money to buy a relatively expensive kit and Lycoming engine to go with it, keeping it all easy and predictable- which is what most RV builders want.

For less expensive kits, the price of a Lycoming, Jabiru or Rotax is hard to swallow, hence you see a lot with VW power here. Engine kits are below $4K: http://www.greatplainsas.com/sclgblock.html all new parts, forged cranks and pistons, ready to assemble. They have this down to a science. That's very appealing in my view and it seems many in that market agree.

When we have crate engines at around $6000 for 400hp and PSRUs for just over $3K. It's hard not to think about the possibilities with a new IO-540 hovering around $48K. The attraction of spending $15K FF vs. $50K is too much for some...:) Gotta give it a try. You're certain to learn a few things and a few lessons along the way.
 
I've yet to build an RV, but I suspect most builders consider the resale value of their hard work and investment. The engine is the heart of the machine. And what engine is the general aviation populous familiar with and most likely to consider in a purchase?
 
Tim, I think you're pretty close to the mark, but I think my phrasing would be 'probability of success' instead of 'reliability'.

I think someone else in this thread pointed out (and I've said for years), the people most qualified to go down the alternate path are the least likely to do so, and the inverse tends to apply, as well. I don't consider myself qualified, but I'm fortunate to have several good friends who are multi-discipline mechanical engineer/gearhead/welder/scratch-builder. Their offers of assistance was the final nudge I needed to try the alternate path.

Van used to say 'convert your money into a used Lyc' (probably still does), and he's right, for the vast majority. But Snowflake is also right; by now, RV's are pretty much high quality aluminum IKEA. :) I wanted to experiment, beyond proving to myself that I could assemble something. I feel far more comfortable in a proven airframe design with a reasonable and docile stall speed/handling and an experimental engine, than I would in a totally fabricated (or even self-designed) airframe with a certified engine. The only real downside of the airframe is the obvious fact that it's designed with air cooling in mind. Unfortunately, I don't know of any airframes that fit the mission and were designed for liquid cooled engines; certainly none that handle and perform like an RV.

Thanks to Ross for chiming in about how many alt engines are actually flying successfully.

For an amusing read (at least for me), see if anything in this thread sounds familiar. The 3rd post has the 'richest' content.

http://www.boatdesign.net/forums/diy-marinizing/auto-engine-marinization-650.html


Charlie
 
The resale price concept surfaces frequently in these discussions. I'd submit that you may get out what you put in in the end but Lycomings are poor investment opportunities as are RVs.

If people are more worried about how much money they will lose buying the kit, building and selling an RV, perhaps they shouldn't start. You're not going to get out what you put in. One minute with your calculator and the average selling price of a used RV will tell you that. Few people are actually getting the $85-100+K they put into a 2 place RV, 10 years down the road.

We could also look at how many hours most people are flying and how long they keep their aircraft. I doubt if the majority of RVs get more than 500 hours on them in the first decade looking at the typical sales ad. It seems most start out flying lots in the first few years, then usage drops off.
In my case, I dropped about $15K less on my FF than a typical Lycoming installation of the era and was able to make 12% on that money in investments. That was about $40K at the end of 10 years for me. These days, you'd be fairly fortunate to make 6%, depending on your investments but you can see in the end, you may end up with about the same amount of money in your pocket even if you get 30-40% less when you sell the aircraft with an auto conversion.

I built my RV to fly it, not sell it. In the end, if I sell it at the 20 year mark for $25K even, I'll come out fine since the money I saved has been earning interest for 20 years.
 
But Snowflake is also right; by now, RV's are pretty much high quality aluminum IKEA. :)

I don't want to hijack the main subject of the thread but since this has come up in the discussion....

The above statement is only true to a certain point.
As soon as a builder deviates from the plans in any way, they could be inducing a design problem that will unknowingly bite them later.

That is the whole premise of certificated airplanes. The have evolved into a proven design (either over time, or by lots of testing; or both) and every one of them is the same, so they should all have the same known level of reliability.

RV's have somewhat evolved in the same way and builders can benefit from that.
When they deviate from the plans they are loosing some of that benefit (to what degree depends on how extreme the deviation is).

Example - The fuel systems for all the RV's has now been pretty well proven. A large percentage of the fuel starvation accidents in RV's have been airplanes that had fuel systems modified to some degree from what is in the plans.

This same dynamic exists with any of the systems or structure in an RV. Choose a different power plant... you reset the experience and testing clock to zero (or what ever value exists from others if you exactly copy an installation others have done).

Not saying that people shouldn't experiment. Just pointing out that when you do, you are influencing the level of comfort that you should have regarding your IKEA airplane ;)
 
I don't want to hijack the main subject of the thread but since this has come up in the discussion....

The above statement is only true to a certain point.
As soon as a builder deviates from the plans in any way, they could be inducing a design problem that will unknowingly bite them later.

That is the whole premise of certificated airplanes. The have evolved into a proven design (either over time, or by lots of testing; or both) and every one of them is the same, so they should all have the same known level of reliability.

RV's have somewhat evolved in the same way and builders can benefit from that.
When they deviate from the plans they are loosing some of that benefit (to what degree depends on how extreme the deviation is).

Example - The fuel systems for all the RV's has now been pretty well proven. A large percentage of the fuel starvation accidents in RV's have been airplanes that had fuel systems modified to some degree from what is in the plans.

This same dynamic exists with any of the systems or structure in an RV. Choose a different power plant... you reset the experience and testing clock to zero (or what ever value exists from others if you exactly copy an installation others have done).

Not saying that people shouldn't experiment. Just pointing out that when you do, you are influencing the level of comfort that you should have regarding your IKEA airplane ;)

Agreed. Most people know a different engine will involve a lot more testing and work now after reading various trials and tribulations.

The second point is very important. Things like fuel system changes can readily bite you. I suggest anyone using an alternative engine check with other successful people on what to do and what not to do. Good systems design is critical to keep the prop turning. We have some proven rules here which have been validated by tens of thousands of flight hours. Benefit from that knowledge and experience. Same goes for cooling and electrical/ignition.
 
Subie PSRU

The 2d guy (I believe) to take over Bud Warren's PSRU's development is now set up at Hicks (Auto PSRUs) and is doing a new back plate for a friend of mine, so he can hopefully get his Eggie engine to operate reliably (without extraneous vibrations, bad harmonics, etc.). His price is listed at $10K, so not in that $3K range. See: http://www.autopsrus.com/psru-for-subaru
He of course also has the LS1 version of the PSRU for the higher HP, V-8 crowd.

The only $3K priced PSRUs I have come across in the last few years (that have a track record of success) would be finding a good used Tracy Crook PSRU; of which there are no doubt quite a few out there associated with abandoned projects, etc.

Doug

P.S. When I started typing my reply, Charlie's post hadn't updated, so it looks like he has some good info. on cheaper PSRUs out there...
 
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The 2d guy (I believe) to take over Bud Warren's PSRU's development is now set up at Hicks (Auto PSRUs) and is doing a new back plate for a friend of mine, so he can hopefully get his Eggie engine to operate reliably (without extraneous vibrations, bad harmonics, etc.). His price is listed at $10K, so not in that $3K range. See: http://www.autopsrus.com/psru-for-subaru
He of course also has the LS1 version of the PSRU for the higher HP, V-8 crowd.

The only $3K priced PSRUs I have come across in the last few years (that have a track record of success) would be finding a good used Tracy Crook PSRU; of which there are no doubt quite a few out there associated with abandoned projects, etc.

Doug

P.S. When I started typing my reply, Charlie's post hadn't updated, so it looks like he has some good info. on cheaper PSRUs out there...

I'm encouraged by Jeff Ackland's success on the P85 so far with the Ballistic drive. If these prove out, it will be hard for the traditional drive guys to charge over $5k (or $10-$15K) for one. When drives are worth more than twice as much as a new engine, the whole concept becomes questionable. Inexpensive, reliable drives make the auto conversion much more attractive and feasible.
 
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Totally agree, Ross, but the really sick thing is that a brand new LSx motor for $6K and a $10K redrive is still *ONE THIRD* the price of a 6 cyl a/c engine.

$32 Thousand of wiggle room there for cooling system development....
 
Totally agree, Ross, but the really sick thing is that a brand new LSx motor for $6K and a $10K redrive is still *ONE THIRD* the price of a 6 cyl a/c engine.

$32 Thousand of wiggle room there for cooling system development....

Yup. My engines was worth about $3000 all said and done and the drive about the same, so say $6000. At the time, a new Lyc was $22,000 I believe. I couldn't justify that cost and I didn't want an air cooled engine and the same sort of "5.0 Mustang" RV anyway. I wanted to design, experiment and learn. Learn I did, with some hard lessons along the way. Priceless education IMO but I'm not one of the typical RV builders cross section either. I totally understand why most RV builders want the Lycoming up front and if that fits your desires and mission, it's the right choice for you.

Understanding what works and what doesn't has come a long ways in that 13 odd years since I designed my FF installation. With the forums and internet groups, many experimenters are able to share and learn so as not to repeat going down many of the wrong paths others did before them.
 
Sixty four posts, and no design or engineering discussion. It it any wonder that alternative engines are not understood or accepted?
 
Sixty four posts, and no design or engineering discussion. It it any wonder that alternative engines are not understood or accepted?

I doubt if there is much genuine interest here since 99+% of VAF people are going with the Lycoming anyway. I usually save most discussions and data for other forums where people are immersed already in a conversion or the majority is more open minded and receptive to the possibilities. If anyone is really interested in pursuing a Subaru, GM, Ford, Honda or Suzuki conversion, they can just email me directly and I can put them in touch with people who are actually flying the stuff. I've published my journey on my website for those interested.

I think this thread was more of probing of attitudes and motivations than one where you'd find a lot of technical information. Most of the successful folks flying RV conversions tired long ago of trying to post useful info here. They just fly their airplanes. There are still at least 30 active Egg Subarus flying mostly in RVs and Glastars with a bunch in the 300-400 hour range and a handful over 700 hours now. Most of those folks confine their discussions to the restricted Subenews forum and Flysoob.
 
Its a hard road

I am VERY interested in "alternative" engine powered aircraft.

The LS engine seems to be a great engine.

Why are we not seeing these "alternative" engines powering the Sport Class at Reno? I know there have been 1 or 2 over the years but its not common
 
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12,000+ readers, including some of the brightest people on earth, makes VAF a bad place to discuss alternate powerplant technology?

Note I'm not talking about another endlessly repetitive opinion festival.

Here's a fact...if an alternative powerplant installation won't pass qualified technical review, it probably isn't any good. The people hanging out on closed alt engine forums are not any more qualified, and the overall talent pool is far smaller.
 
I am VERY interested in "alternative" engine powered aircraft.

The LS engine seems to be a great engine.

Why are we not seeing these "alternative" engines powering the Sport Class at Reno? I know there have been 1 or 2 over the years but its not common

The LS engines have vast support from GM and the aftermarket for racing parts now. The Algie LP1 was using a turbocharged LS engine and was designed to race at Reno. Unfortunately it was embroiled in a nasty lawsuit just before it was ready to fly. Real shame given David's huge amount of work and the new ideas it embodied.

If Reno racing continues, I believe we'll eventually see some LS powered Sport Class aircraft there. On paper, the engine is vastly superior and a lot cheaper compared to the air cooled stuff but it will take someone with skill and vision to fit one to a competitive airframe and show the world.
 
12,000+ readers, including some of the brightest people on earth, makes VAF a bad place to discuss alternate powerplant technology?

Note I'm not talking about another endlessly repetitive opinion festival.

Here's a fact...if an alternative powerplant installation won't pass qualified technical review, it probably isn't any good. The people hanging out on closed alt engine forums are not any more qualified, and the overall talent pool is far smaller.

VAF does have a large percentage of very savvy folks for sure but the majority are not experimenters with their builds by my definition. Wrong audience IMO.

You can review something to the nth degree all you want and that can be useful but the real proof of the concept is to build it and fly it for hundreds of hours. I can't count how many times alt people have been brow beaten by "experts" and even closed minded A&Ps and engineers saying something won't work yet, there they are flying it successfully years later.

A lot of discussion is simply a waste of time when you could be wrenching, flying and learning. I can think of one fellow who hangs out here with Ford V8 powered Zenith who deleted all his posts on one forum and left for a long time due to the abuse. I believe he's got over 500 hours on it now with minimal issues early on, very reliable now. So much for the "expert" commentary in this case.

https://www.backcountrypilot.org/fe...-beast-zenith-ch801/35-the-beast-zenith-ch801

Elegantly clean and simple: http://www.beltedair.com/Zenith701.htm

There were lots of people burned by vendors with untested and unproven FF packages and their poor support. These people were hoping to enjoy their aircraft with minimal work, just bolt on and fly. Many didn't work out that way, some did. There is another group of people like Ben Haas above who roll their own and have been very successful and happy to share their recipe, failures and triumphs. These are the people who contribute the most to the cause, spurring others along. Jeff Ackland of Legend and Radial Rocket fame is another: http://altitudegroupllc.com/portfolio/p85-progress-photos/ These folks just get along and do it. My hat's off to them.
 
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Further to my last post. Are VAF members interested in a lower cost engine alternative? I think so, judging by the number of views on the topic over the years but what would appeal to most is a genuine, FF kit that's well developed, well proven and well supported that comes in at something like half of the current new Lycoming choices.

Do I see that existing today? No I don't. There is nothing in the 150-200hp class that's available today fitting those requirements in a vendor offering.

I see better chances with new, clean sheet, direct drive, air cooled opposed engines under development. To make a good business case, these engines have to cost something less than a Lycoming or why bother to switch from the known product? $25K auto conversions in this hp range never made good business sense to me.
 
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Further to my last post. Are VAF members interested in a lower cost engine alternative? I think so, judging by the number of views on the topic over the years but what would appeal to most is a genuine, FF kit that's well developed, well proven and well supported that comes in at something like half of the current new Lycoming choices.

To make a good business case, these engines have to cost something less than a Lycoming or why bother to switch from the known product.

Ross you make a good point but cost is not the only factor.

We want same or less installed weight, same or less installed cooling drag, same or more continues cruise HP, same or less fuel flow. When all of these are met and proven by multiple installations, I will probably build one.

I think competition is the main driver in advancing technology regardless if it is driven by war, racing, money, ego, etc.

Currently I am not driven by anything to enter the competition.
 
You forgot reliability

We want same or less installed weight, same or less installed cooling drag, same or more continues cruise HP, same or less fuel flow. When all of these are met and proven by multiple installations, I will probably build one.
First and foremost on most pilot's priority list is engine reliability.

There is little or no competition in the aircraft engine business.
There is almost nothing to compete for, compared to the automotive engine
market.

What is overwhelmingly evident is the unbridled enthusiasm of idealists
in pursuit of something "better with all the above mentioned advantages over a Lycoming.
I've watched this debate for 20 years and I have yet to see someone
meeting all those requirements.
I am still interested in auto conversions, always hoping to see someone succeed.
 
I goes without saying that most people expect near equal or better performance and reliability along with the lower price tag.

Like I said, there are no vendor based auto engines for aircraft currently meeting the expected weight, reliability and performance criteria set by existing Lycoming engines in the 150-200hp class. Some one offs have performed very well such as the EJ257 powered RV7s- slightly heavier but a lot faster and equal fuel flows but have not accumulated enough flight hours to prove the reliability part yet.


The 2 LS powered Pawnees proved that you can have everything above for a lot less. Would just take someone with the skills, time and finances to test it properly and bring it to market IMO. I just don't see anything in this hp class on the horizon at this time though so I'm looking to see how the new opposed designs pan out over the next few years.
 
Have not read all of this thread so this may be a repeat but the UL engine seems well engineered.

Hangar neighbor with a Zenith 750 has the UL engine. It is running fine.

http://www.ulpower.net

But it may not qualify as a alternate engine....it is an aircraft engine.

Engineering in auto engines is mighty deep just not engineered for and aircraft.
 
Have not read all of this thread so this may be a repeat but the UL engine seems well engineered.

Hangar neighbor with a Zenith 750 has the UL engine. It is running fine.

http://www.ulpower.net

But it may not qualify as a alternate engine....it is an aircraft engine.

Engineering in auto engines is mighty deep just not engineered for and aircraft.

Well, since the responses to the post about Franklin a/c engines (around almost as long as Lyc) is what pushed me over the edge to start this thread, I'd say it qualifies. :)

As far as 'for an aircraft' goes, does the engine know where it is? If it doesn't overheat, and torsional/bending issues are dealt with properly (unfortunately, those are not in many conversions), I suspect that an engine isn't smart enough to care where it is.

Automotive engines (well, typically truck engines, but same block/crank w/hotter cam) survive just fine in marine use, with duty cycles that closely mimic a/c use. They also survive just fine in a/c; we just don't hear about them a lot on an RVx forum.

Charlie
 
I pay attention to alternative engines, because eventually, one won't be "alternative" anymore. Right now, Lycoming seem to present the best option for my list of requirements.

I commend everybody who successfully runs a non conventional engine, it's just too experimental for me.
 
Where are they?

"The 2 LS powered Pawnees proved"

Just where are those operating? Any links or video?


The Audi 3.0L TDI V6 has 420 ft lbs of torque. Is anybody aware of any aviation instals with this?
 
"The 2 LS powered Pawnees proved"

Just where are those operating? Any links or video?


The Audi 3.0L TDI V6 has 420 ft lbs of torque. Is anybody aware of any aviation instals with this?

Links provided earlier in the thread, check Post #51. Flying in Australia for many years.

From 2 Emails from a fellow involved with the tug projects starting in 2007- "We operate two PA25s one in each of your two "camps" - one with a Lycoming
0-540 and the other with an LS1 V8 engine. You might have guessed that the V8 is going gang-busters while the 0-540 failed in flight 2 weeks ago -fortunately, in the early part of the flare and the engine was at flight idle, so no damage to the airframe/pilot. Seems a magneto bearing collapsed, pieces then fell into and broke the camshaft drive gear, stopping the engine. Repair cost will be that of a new engine!"

From 2010- "Very happy with our only LS1 engine. Never missed a beat. Few problems getting the exhaust right, but think we have it now. Past 500 hours on the engine. Makes a brilliant tug."

In the course of about 5 years, the Lycoming engine suffered 4 serious failures and numerous cylinder replacements.
 
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This would be my choice for an alternative motor!

siemens-electric-plane-motor.jpg
 
Alternative

Some how I think the Electric Motors are going to be the " Go To " alternative
power plant in the very near future . Might not be a cross country motor , but
great afternoon "1 hour Fix" plane motor . Rv3 ????
 
Fuel consumption

My Subaru is very economical for local sight seeing flights. I burn 3 GPH at 100kts on autogas. I took a local Cherokee pilot for a 30 min flight over the local hills and burned 1.8 gallons. He was impressed that our flight cost about 6 dollars in fuel!

-Andy
RV-9A
 
Andy has one of the higher time Egg conversions now, showing that a number of these are still working well years later.
 
Andy has one of the higher time Egg conversions now, showing that a number of these are still working well years later.

I thought one core root cause for the Subie installation failures was the gearbox (PSRU) - what does Andy have? And what is different about it to make it successful?
 
The original 4 cylinder engines with Gen 1 gearbox were overall quite reliable. A number of those, including one of the highest time ones is that configuration. The problem was they were only putting out about 125hp at best so performance was a bit weak.

Problems started showing up when the more powerful six cylinder engines came along. The Gen 1 box was not up to the task so the Gen 2 came out and it wasn't so good. Then the Gen 3 was designed which was much stronger. Some people have had good service from the Gen 3s, others have had weld breakages, bearing issues, oil leaks and spline wear or breakage issues. A dual mass flywheel came out on the later 6 cylinder setups which may be better than the solid flywheel used earlier from a TV POV however I know of several solid flywheel sixes with pretty high time and no issues. The solid flywheel setup, Gen 1 and Gen 2 boxes were declared unairworthy by Eggenfellner a few years back now. The welded areas inside the gearbox are hard to inspect and a bit worrisome. Welding in these spots was not a good idea IMO.

There are several known problems with the Gen 3. Alignment of the gearbox on the engine is critical and often not done correctly. Failures due to poor alignment maybe should not be blamed on the GB. There were no dowels used on the GB to properly facilitate this like you'd find in a properly engineered piece but there is a procedure and tool to accomplish this task that works well.

Type of lube used on the spline shaft is critical. The shaft does not engage the internal spline fully as designed, another puzzling oversight.

The Gen 3 box demands at least yearly inspections, especially of the spline shaft and lubrication state. I don't consider it as reliable or trouble free as the Marcotte or Autoflight boxes but it gives decent service for the most part when maintained and inspected properly.

The gearbox issues are known by the users on the Subenews group which is dedicated to highlight problems and experiences with the Eggenfellner packages, find solutions and fixes for them and keep the group flying safely. They distribute inspection and maintenance information which is a very valuable asset to all involved.
 
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Subie H.P. ?

The original 4 cylinder engines with Gen 1 gearbox were overall quite reliable. A number of those, including one of the highest time ones is that configuration. The problem was they were only putting out about 125hp at best so performance was a bit weak.

Hi Ross,

Always happy to see your insightful comments. The one above begs the question: Why does an engine Subaru rated at 160 HP at the flywheel, I presume, only put out 125 hp in an RV? Surely the redrive isn't sucking all that power up? The first RV equipped with an EGG could only get around 140kts. Guess that should have been a tipoff. I bailed luckily enough on that whole scene when I criticized the business practices of same.
 
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Hi Ross,

Always happy to see your insightful comments. The one above begs the question: Why does an engine Subaru rated at 160 HP at the flywheel, I presume, only put out 125 hp in an RV? Surely the redrive isn't sucking all that power up? The first RV equipped with an EGG could only get around 140kts. Guess that should have been a tipoff. I bailed luckily enough on that whole scene when I criticized the business practices of same.

Was mainly due to changes to the intake manifold and the fact that the engine was not geared for peak hp rpm.

A supercharged 2.5 was introduced to help find some more power and this surprising worked pretty well for many users. It simply added an Eaton supercharger to the basic EJ25 engine and stock ECU.

Then there was the STi disaster. This took the EJ257 turbo engine, removed the turbo, added an Eaton blower and complicated/unreliable boost control system instead and tried to use the very complicated stock ECU for this engine. I believe every single one suffered either a forced landing or scared the pilot enough times with ECU issues to abandon the original setup.

The E6 and H6 engines (EZ30) were reasonably reliable in most cases but quite porky. They were down on power again from stock due to restrictive intake and exhaust systems again, plus mods to the VVT system, probably putting out around 170-180hp.

A few EZ30 turbos made it to market. Most I know of broke pistons but I have a customer in Norway with one having around 400 hours (never touched internally) on it now in an RV7, 170 KTAS on 9.25 gal./ hr. The turbos were not matched properly and they had a funky boost control system because of that but they worked ok at medium altitudes.

At the last was a handful of EZ36 engines, probably putting out close to 200hp but almost all of them blew up (piston failures) in fairly short order due to improper mapping of the ECUs.

Most customers got very good, fresh used engines, others got some pretty bagged out ones full of sludge or rust. The later engines were never even opened up for inspection it appears.

IMO the EJ257 STi 4 cylinder engine had the most potential being light enough to compete with the Lycoming and serious hp potential. The stock ECU and the supercharger were the big mistakes here. I was involved consulting on two RV7s with STi engines converted back to turbo with properly matched Garretts, intercooler and our programmable SDS ECU. These aircraft were super fast- Vne in level flight at low boost and gave decent fuel economy as well. One is still flying up north of me and so far, pretty reliable.

Done right, these are probably the best base engines to start with for an RV conversion. New short blocks are available for around $2800 and you can fit SOHC heads to save about 15 pounds. Good used, complete EJ257s go for around $3500-$4500 usually. Rated at around 300hp stock, depending on year so not working very hard to put out 200hp for takeoff and 150 for cruise.

One thing we've found is that these engines generally don't like a steady diet of 100LL, usually leading to valve problems. That can be an issue on extended cross countries where it's hard to find unleaded fuel enroute.
 
Subaru gearboxes

I have the Gen3 gearbox and dual mass flywheel. IMO the dual mass flywheel is the single most important update for any gearbox. It serves as a torsional damper, reducing the impulse from the engine by probably an order of magnitude. There have been no failures of this combination (as far as I've been able to determine). It's also lighter than the solid flywheel.

With the gear ratio of 2.02 it allows all the power potential of the engine. The performance of the engine is comparable to an O-320 with fixed pitch prop. The weight is comparable to an O-360. The advantage of this engine are: ease of starting and operating, ease and cost of maintaining, smoothness of operation and overall fuel economy. Disadvantages are: power to weight, possible future failures that are unknown due to small numbers operating, resale value, might be hard to maintain for a non do-it-yourselfer.

The support of the community on the internet is the only thing that has made this engine option viable. We have chased down dozens of problems and found fixes for them.

Performance in an RV-9 is pretty good. My top speed is 173KTAS. I can climb to 9500 feet in 10 minutes solo. That climb is with reduced power at 110 KIAS and burning under 10GPH. 150KTAS cruise is at 7GPH low altitude and 6GPH at high altitude.

-Andy
 
As noted previously, you don't have a dual mass; Jan removed one of the masses, while retaining the springs. It was a very clever use of OEM parts.
Nor do you have a damper.
I'm sorry, but advancing the art will require at least some fundamental understanding.
Yeah, you can split hairs on the terminology, but the combination works pretty well as Andy noted. I think he understands, despite the questionable naming. His assessment is spot on.
We should probably be calling it something like a '2 piece spring separated' flywheel. The springs soften the pulses, friction provides a bit of damping, so it does act a bit as a torsional damper - apparently enough to get the job done (so far anyway).
Instead of looking for the negatives, why not look for the positives? That is what advances the art.
I have 400 hours on my H6-Gen3 and the insides of my GB still look brand new, and my (lubricated) spline shaft shows no signs of wear.
 
Good to hear

. . .
I have 400 hours on my H6-Gen3 and the insides of my GB still look brand new, and my (lubricated) spline shaft shows no signs of wear.

Well, that is good news, do you attribute your success to the general installation overall, or did you do something in particular (different than others) to generate this success?
 
Well, that is good news, do you attribute your success to the general installation overall, or did you do something in particular (different than others) to generate this success?

Quite a number of people who've stuck with the Egg conversions are happy with them and they are working well with minimal problems. I think the people not in the actual loop think they were all a disaster which isn't the case. I can count over 15 people who correspond with me fairly regularly who have something around or over 400 hours now on them. Pretty much has just been oil changes and spline inspection/ lubrication annually. My customer in Norway likes his turbo six enough that he's doing another one for another aircraft now. People love the super smooth running, easy starting and minimal fuss when flying. You do have to have the rad setup working well but most have that licked and there are few issues in hot weather.

The Subenews forum has been invaluable as stated before to identify common problems and fixes. The people who've implemented what's been learned have generally had pretty decent service from their packages. Lazy people who don't do the spline maintenance or listen to other critical advice (like ECU programming and checking timing offset) have often had plenty of tears but I can say same the same thing for many other auto conversions I've assisted on too.
 
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As noted previously, you don't have a dual mass; Jan removed one of the masses, while retaining the springs. It was a very clever use of OEM parts.

Nor do you have a damper.

I'm sorry, but advancing the art will require at least some fundamental understanding.

http://www.vansairforce.com/community/showpost.php?p=756448&postcount=89

I call it a dual mass flywheel because that is it's name. The second mass is the plate that has the female splines, the splined shaft, the rotating part of the gearbox and the propeller itself. The function of the thing is what we care about. I don't know if a damper is the proper term, but the springs allow the second part of the flywheel to rotate many degrees (maybe 60 degrees) from the crankshaft portion. This means that the impulses from the crankshaft cannot be transferred to the gearbox except through springs. It's like trying to hammer a nail with a spring faced hammer. It preserves the gears, bearings, and prop hub.

-Andy
 
Well, that is good news, do you attribute your success to the general installation overall, or did you do something in particular (different than others) to generate this success?
I haven't done anything special regarding the installation. As Ross has noted, there are plenty of successful installations. Like anything else, you don't hear much about the successes, but the problems are big news.
 
Alternative engine.... not for the lazy.

Not for those with lack of ingenuity.
Not for those without some degree of skill.
Not for those who aren't willing to continue learning.
Not for those without intense attention to detail.

How would you like a really long lesson in patience?
How about another lesson in focus?

Determination?
Faith in one's own abilities?

Can you search? Can you read?

How about networking?

Did I mention patience?

I'm getting closer though.

Maybe I too will only get 16 hours into phase 1 maybe less. I decided to go down this road-- I'm going to carefully see where it takes me.
 
What are you building Bill?


Vans rv7. Mazda 13b turbo. Reserved---N713BT.

IF they gave a S--t here about putting my configuration in the signature it'd look something like this

Tracy's rd-1b Ec-2. (need an EM-)
Mount by Ed at tech welding.
Greddy S5 exhaust manifold
t04-b V 1.15 A/R hot side
Manual waste gate
Cold-side mount denso alternator w/ external regulator
top-mount standby alternator
Griffin cold-side mount radiator
CX Racing 30 row oil cooler
Davies-Craig EWP and controller
UHS spinner
IVO 3 bladed magnum

All fits under a Sam James holey


I spend more time over on the Lancair online flyrotary board. Though I like the functionality of this board (including the search function) I try to stay away from the drama. I was called a Troll here on this alternative engine forum-- so now I stay under the Bridge.
 
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