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  #41  
Old 01-17-2013, 09:47 PM
shogan50 shogan50 is offline
 
Join Date: Dec 2012
Location: Mukilteo
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Thanks for the feedback Randy. Knowing what you know, would you go sub again? I you are ever up to the Seattle area, I would love to see it. I'd also be interested in any cowl/plenum pressures/flows/temperatures you've taken.
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  #42  
Old 01-18-2013, 02:16 AM
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RV10inOz RV10inOz is offline
 
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Originally Posted by Randy View Post
Scott,

To answer your original question at the beginning of this thread, yes I am flying my Sube powered RV. I guess I am one of the crazies that have hung in there and gradually over time most all of the real issues have been resolved.

I started with an Egg STI package with a roots blower on it. It would launch like a dragster at 52" MAP, but there were many problems to be dealt with at that point. I ditched the blower and went with my own turbo installation that worked quite well. The performance was better than what I see claimed by any other 4 cylinder powered RVs, but there were still some reliability issues to be dealt with, mainly due to my own learning curve on turbo installation.

After that I focused more on reliability and had an engine put together trying go get enough HP in a normally aspirated version. The reliability has been great. I have routinely cruised back and forth between AZ and CA with it and I really don't have to worry much about something breaking.

The power level with the NA engine has been somewhat disappointing though. I probably should be happy with it and just keep flying it the way it is but I really got addicted having adjustable manifold pressure. So now I will do another turbo install with a very specially built EJ25 short block mated to SOHC heads. I will use an Aerocharger turbo that eliminates the need for engine oil going to the turbo which is where I had my problems before. If my plans come together the turbo could grenade in flight and I will still be able to fly on to an airport of my choice...

These engines are only as good as the gearboxes that deliver power to the propellers. The Gen 3 gearbox from Egg is a crude design that has been mostly successful. I have over 300 hours on mine and the oil stays very clean. We are still learning in this area and there are some obvious improvements that can be made to that design. One of my next improvements to mine will be to install a good metal chip detector at the drain location to give me early warning of any bearing problems. None of these have fallen out of the sky but a few have had bearing problems. I like the idea of the chip detector for early warning just like my coolant level alarm etc.

It takes time for these designs to evolve into a good reliable package. I don't know of any one producing what we would call a firewall forward package and the ones produced in the past should have been called starter kits or something else...

Randall Crothers
RV7A
I would be putting in a chip detector and magnetic plug, the gearbox I know of here in Brisbane has had a nasty weld failure at about 360 hours. It is nasty, and it beats the heck out of me why hat bearing arrangement is used and why on earth there is welding of any sort involved.

I am in the industrial gearbox industry and all I can say is

Be careful.

Perhaps a scaled up Rotax box would be a good start.
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  #43  
Old 01-18-2013, 06:33 AM
Randy Randy is offline
 
Join Date: Jan 2005
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Originally Posted by shogan50 View Post
Thanks for the feedback Randy. Knowing what you know, would you go sub again? I you are ever up to the Seattle area, I would love to see it. I'd also be interested in any cowl/plenum pressures/flows/temperatures you've taken.
Well that is a tough question. There have been many times that I really just wanted to pull the Sube off and spend 50K or so to put an airplane engine in the thing I don't think I would do it again, but I am not all that sorry that I have done what I have. It has been rewarding to see the good performance I had with the turbo and the reliability I have had with the NA engine. I have enjoyed solving the problems and seeing good results.

I guess the main thing is whether you really enjoy experimentation and can deal with having a large investment and still not be able to just go to the airport and go flying with your buddies that have "normal" engines in their planes.

For a person like me, it is irritating as **** to go flying with other RVs and deal with them getting smaller in the windshield. I did not have to deal with that with my turbo engine and I really look forward to having similar performance along with the reliability.

It should be a lot easier now than it was. There is much more information available now regarding what works and what doesn't.

Regarding cowl pressures, the important thing is to actually measure them and not assume anything about how air is going to flow. A simple gauge that measures inches of water can be had for under $50 and save many headaches if it just gets used. From my experience, radiators, oil coolers, and inter coolers will perform pretty well once the differential pressure across them gets up around 6 or 7 inches. It only takes a little leakage to allow the differential pressure to equalize and destroy the flow. Air scoops and NACA inlets cannot do their job if they are having to exit air into a high pressure area, like the inside of the cowling. The pressure in my cowling behind the radiators will have around 7" water column pressure, so to get good flow to another exchanger requires the air inlet or scoop to overcome this pressure before any flow can take place. It is easy to waste a bunch of time putting things together that looks like it will allow good air flow and cooling...
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  #44  
Old 01-18-2013, 07:37 AM
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rv6ejguy rv6ejguy is offline
 
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Quote:
Originally Posted by RV10inOz View Post
I would be putting in a chip detector and magnetic plug, the gearbox I know of here in Brisbane has had a nasty weld failure at about 360 hours. It is nasty, and it beats the heck out of me why hat bearing arrangement is used and why on earth there is welding of any sort involved.

I am in the industrial gearbox industry and all I can say is

Be careful.

Perhaps a scaled up Rotax box would be a good start.
I agree, the Egg Gen 3 gearbox is not a great design IMO. Welded gear parts don't belong in an aircraft gearbox and this will always be a constant worry for owners. It seems that some weld processes were better than others as many have had no problems to date while others had issues very early on.

There have been multiple other issues although not widespread across the board. A failure in the gearbox even if a "soft" failure is often the last straw for Egg owners. While fixes and new parts are being developed by the support group for the Gen 3, the best solution would be a new gearbox design.
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Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 441.0 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
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  #45  
Old 01-18-2013, 11:14 AM
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DanH DanH is offline
 
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Quote:
Originally Posted by rv6ejguy View Post
I agree, the Egg Gen 3 gearbox is not a great design IMO. Welded gear parts don't belong in an aircraft gearbox and this will always be a constant worry for owners..... While fixes and new parts are being developed by the support group for the Gen 3, the best solution would be a new gearbox design.
Recall we did attempt to run a thread strictly limited to technical aspects of Egg systems, notable among them the Gen3 gearbox and the soft element flywheel (not a "dual mass flywheel"; it is not dual mass as applied here). Still, I completely missed welding in the gearbox. What is welded to what and how are they failing?

BTW, it seems like a pretty good example of why pushing for technical detail has merit.
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Last edited by DanH : 01-18-2013 at 11:16 AM.
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  #46  
Old 01-18-2013, 12:43 PM
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rv6ejguy rv6ejguy is offline
 
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Quote:
Originally Posted by DanH View Post
Recall we did attempt to run a thread strictly limited to technical aspects of Egg systems, notable among them the Gen3 gearbox and the soft element flywheel (not a "dual mass flywheel"; it is not dual mass as applied here). Still, I completely missed welding in the gearbox. What is welded to what and how are they failing?

BTW, it seems like a pretty good example of why pushing for technical detail has merit.
After some input shaft failures, the solid flywheels were "grounded" and the "fix" was to install the "dual mass" flywheels on all engines and verify shaft alignment, the gearboxes did not use alignment dowels... There is little science behind this recommendation and I believe we could still continue to see various failures on the drives. F2 amplitudes do appear to be lessened noticeably with the dual mass though but who knows in the higher ranges without instrumentation. Some people still reported F1 problems on both flywheel types which is around 250-350 rpm and results in serious kickback as the engine fires just off the starter in some but not all cases. There appears to be a number of variations in parts Egg supplied after an extensive technical poll was conducted and people measured or took photos of what they had. These variations can maybe explain why some users have hundreds of hours of trouble free operation while others have had multiple problems with low time on the parts.

Two gears are welded together and in a place that is hard to inspect without a small borescope or complete disassembly. Welds crack or fail. I got a little lost with the many different problems cropping up and I'm just glad I don't have one of these boxes. Welding is of course a bit concerning on hardened and heat treated parts. I've done it in race car gearboxes but it has to be done carefully and precisely to be reliable. I simply would not weld gears used in aviation.

The group has some smart guys working on fixes and service/ inspection procedures, compiling tutorials etc. Without these, most guys would simply be lost. Kudos to the great guys in the group for stepping forward with this help.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 441.0 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi2.htm



Last edited by rv6ejguy : 05-11-2013 at 07:57 PM.
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  #47  
Old 01-18-2013, 05:15 PM
Jerry Cochran's Avatar
Jerry Cochran Jerry Cochran is offline
 
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Location: Sherwood, Oregon
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Quote:
Originally Posted by SvingenB View Post
I agree. You have to offer some kind of benefit. Eggenfellner does that with the price tag, half the price of similar performance aero engine (rotax, jabiru, UL etc).
Yup. He also did that with his original 2.5 Subie which was alleged to have 165hp, but for some reason only put out maybe 75% of that or less ( HP loss in gearbox? Maybe.). His pitch was that it was equal to a Lyco O-320 at half the price and a lot of folks went for it. Let us hope that the Honda Fit engine works out better. Like the Subie, the Fit engine itself is fine in cars, that they were designed for. It's all the peripherals as noted here and elsewhere that are the tough nuts to crack. True believers may disagree...

Jerry
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  #48  
Old 01-18-2013, 06:42 PM
simpkinsona simpkinsona is offline
 
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Location: Vacaville, CA
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Jerry hit the nail on the head. Egg over promised on the HP and spent the rest of his Subaru career on trying to improve it. This resulted in heavier, more complex motors and no end of suffering for his customers. If he had advertised it as 140 HP and claimed performance of a fixed pitch O-320, he would have been able to keep it simple and maybe succeed. With the electric adjustable prop, mine climbs and cruises like an O-320 fixed pitch.

-Andy
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  #49  
Old 01-18-2013, 11:08 PM
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rv6ejguy rv6ejguy is offline
 
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Quote:
Originally Posted by simpkinsona View Post
Jerry hit the nail on the head. Egg over promised on the HP and spent the rest of his Subaru career on trying to improve it. This resulted in heavier, more complex motors and no end of suffering for his customers. If he had advertised it as 140 HP and claimed performance of a fixed pitch O-320, he would have been able to keep it simple and maybe succeed. With the electric adjustable prop, mine climbs and cruises like an O-320 fixed pitch.

-Andy
Yep, he just really needed to listen to someone who really knew engines and guide him along with proper mods to them rather than ill-conceived and untested ones. The first engines which developed about 125-130hp were actually pretty simple, cheap, light and reliable but mostly suitable for planes which originally used O-235s.

The quest for engines to equal the performance of O-360 led to the supercharged 2.5 and Sti. The SC 2.5s actually worked better than the Stis which were a complete disaster from the get go. The core engines were great but the crippling mods made to them were an accident waiting to happen as many unfortunately found out. Fortunately, once the bad mods are addressed, the STi makes an amazing aero engine as we have proven a couple times now- blinding speed and comparable to Lycoming fuel flows and only a bit heavier.

The six cylinder engines were just plain heavy and saddled again with poor intake and exhaust systems, failed to match O-360 performance. Still , we have many people flying them that love them for their smoothness and they have not had problems to date.

If Jan had only stuck with the Sti, properly developed it, keeping the turbo instead of the Eaton SC and addressed all the other problems with the VVT system and EFI and built and tested a solid gearbox, he would have enjoyed great continued success I think. A lot of ands I know but the Sti was the right direction, wrong recipe. The Getson/Inkster 7 shows what can be done with the STi.

So the question that started this thread... If anyone is thinking about replacing an Lycoming with a Subaru, my recommendation would be an EJ255/257 based 4 cylinder or for someone wanting a superX, the 230hp EG33 six cylinder has proven to work well in several other aircraft.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 441.0 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi2.htm


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  #50  
Old 01-18-2013, 11:09 PM
shogan50 shogan50 is offline
 
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Location: Mukilteo
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Anyone have an exploded assembly view of one of these gearboxes or photos? I've not followed, but as a mechanical engineer I'm quite curious.
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