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  #1  
Old 11-29-2007, 07:34 PM
Yukon Yukon is offline
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Join Date: May 2006
Location: Phoenix, Az
Posts: 920
Default Egg Gearbox Failure

Here is some info on a recent Gen 2 gearbox failure (


See answers below


Steve


--- In subaruaircraft@yahoogroups.com, "Larry" <simpsonl@...> wrote:
>
> Steve,
>
> Could you provide a few more details about your failure? I do not
> recall seeing it mentioned on the group before. Appearance of your
> oil at change?

-------- The oil at the time of failur had 36 hours (mobile 1 75W-90
synthetic)The oil color was light and no observable particles in the
tube.



Any other warning signs before the failure? Noise?

-------- My Gen II Gearbox temps always ran hotter than the engine
and the oil temps. (Normal temps for me were 205 - 210F with climbing
temps for any power above 2100 rpm) In retrospect I have learned
that this was probably a warning sign. After the failure, I used a
loaner gearbox to get the plane home and it ran significanlty cooler
(15-20F)than my original gearbox so I speculate that there was
something amiss with my original gearbox. The day of the failure, it
was very hot in Atlanta and my GB temps were running about 215, this
was probably another warning sign that I did not notice.


> Spiking temps? How catastrophic was the failure? Did it occur in
> flight?

-------- Failure was in flight, After cruising for about 1 1/2 hours
on the day of failure. There was a sudden appearance of loud
squealing noise and the gearbox failed about 3 minutes later. (gears
stripped and engine raced, I shut the engine down in flight) Pure
speculation on my part is that one of the bearings failed and after
the bearing siezed, it lead to a failure of the gears. Again, in
retrospect, I think the high temps were telling me about a problem
that I did not recognize. The dramatic difference in the loaner
Gearbox (much cooler temps) tells me that this was an issue
associated with my gearbox that may or may not be present in other
units. The new Gen III gearbox is much much cooler running in my
plane.



>
> I am also running a Gen 2 (blue front) PSRU and it typically runs
in
> the 200-210F range at full throttle and any prop setting above 2000
> RPM. My engine temps are usually about 30 degrees lower. I have a
2
> inch blast tube and a 1.25 inch blast tube to the bottom and left
> sides of the unit respectively. Aircraft Spruce delivered another
2
> inch tube and some scat today which will be installed next week for
> the right side.
>
> At 25 hours TT and 10 hours since the previous change, the Mobil 1
> 75W-90 oil looked slightly gray but there were no visible metal
> flakes on the fine screen that I strained the oil through. I am
> letting the oil "settle" for 48 hours and then will see if there is
> any sediment and if so, if it is magnetic. Then I will send to for
> analysis.
>
> I am upgrading to the Gen 3 in January, but am concerned that I may
> need to curtail my flying until then.
>
> Thanks for your information.
>
> Larry
>
> --- In subaruaircraft@yahoogroups.com, "n62km" <n62km@> wrote:
> >
> > David, I did have a complete gearbox failure on my H6 normally
> > aspirated Gen II gearbox after about 100 hours. It appears my
> > particular unit was behaving differently than most units (running
> hot)
> > so it might not have be a representative sample of most units in
> the
> > field.
> >
> > I have sinced moved to Gen III and have about ten hours on it.
The
> new
> > unit is running much cooler.
> >
> > Steve RV8 H6
>

Last edited by N395V : 12-02-2007 at 07:52 AM. Reason: innappropriate commentary
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  #2  
Old 11-30-2007, 07:47 AM
Yukon Yukon is offline
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Default More Gearbox Info

http://rv-9.com/egg.html
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  #3  
Old 11-30-2007, 08:25 AM
Kahuna's Avatar
Kahuna Kahuna is offline
 
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Location: Gold Hill, NC25
Posts: 2,431
Default

I was sorry to hear abour Steves gear box failure. I did the first flight on that plane. Report here http://www.vansairforce.com/communit...ad.php?t=12643.

Having watched "Subob" (flying friend who used to have a non-egg subaru in his 4) drop 8 Subie engines in his RV-4, there is no chance Id do it. He never failed a gear box, always the lower end of engine. All dead sticks. He had a Ross concentric planetary gear box 2.17:1, Marcotte drive terrain dampener... and through metalergical analysis, concluded that harmonics from the gear box was killing the lower end. He now has a lyco bart 180 in his RV-4. Do not equate Eggs to Subobs, its just one mans experience.

I also went to friend Egg6 RV-10 Dans funeral. Hated that.
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6A, S8 ,
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Last edited by Kahuna : 11-30-2007 at 08:58 AM. Reason: added subob subie detail.
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  #4  
Old 11-30-2007, 04:47 PM
gmcjetpilot's Avatar
gmcjetpilot gmcjetpilot is offline
 
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Posts: 4,832
Default What a Gen II gearbox

What is a Gen II gear box? Is it the latest and greatest from Egg? NEVER MIND I read Yukon's link above, explains it all. The Gen III gearbox was on the tragic RV-10; Kahuna, that must have been very sad indeed, my sincere sympathies.)

Whats a "Subob", a particular brand of engine conversion or just roll your own Subaru?

Ross where are you? What ya think.

Sounds like a TEMP gauge with a real red line temp and and particle sensor for the gearbox would be good idea.
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Raleigh, NC Area
RV-4, RV-7, ATP, CFII, MEI, 737/757/767

2023 Donation Made!

Last edited by gmcjetpilot : 11-30-2007 at 05:01 PM.
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  #5  
Old 11-30-2007, 07:12 PM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
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Location: Calgary, Canada
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Quote:
Originally Posted by gmcjetpilot View Post



Ross where are you? What ya think.
I'm dodging the troll and staying out of these discussions as I said before. I had hoped people would wait for the full NTSB report on Dan's crash before saying anything. The initial report drew no conclusions and there seems to be unusual circumstances involved hence further investigation is merited. We don't know the cause of the power loss in a 7A accident 3 days later either. I don't see the point is speculating about either accident.
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 462.1 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
https://www.youtube.com/channel/UCiy...g2GvQfelECCGoQ


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  #6  
Old 12-01-2007, 12:14 AM
Kahuna's Avatar
Kahuna Kahuna is offline
 
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Location: Gold Hill, NC25
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Quote:
Originally Posted by gmcjetpilot View Post
Whats a "Subob", a particular brand of engine conversion or just roll your own Subaru?
His name was Bob. After blowing up a few Subaru engines, we now call him "Subob."
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Kahuna
6A, S8 ,
Gold Hill, NC25
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  #7  
Old 12-01-2007, 03:33 AM
gmcjetpilot's Avatar
gmcjetpilot gmcjetpilot is offline
 
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Default ha ha

Quote:
Originally Posted by Kahuna View Post
His name was Bob. After blowing up a few Subaru engines, we now call him "Subob."
ha ha ha ha ha ha
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Raleigh, NC Area
RV-4, RV-7, ATP, CFII, MEI, 737/757/767

2023 Donation Made!
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  #8  
Old 12-01-2007, 11:04 AM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
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Location: Calgary, Canada
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Quote:
Originally Posted by Yukon View Post
Of course you are Ross. You are an Egg vendor.
As is often the case, I'm not sure what your point is here? I can only assume you are trying to warn older Egg customers that their gearboxes might fail. This is being discussed out in the open on Jan's site as you have said.

I do think it is counterproductive is to assume that Dan's accident was caused by the Subaru engine any more than the 7A accident 3 days later was caused by the Lycoming engine in it. I know nothing more than anyone else here on either accident. Let's just wait for the facts and maybe we can learn and apply that knowledge to prevent similar circumstances from bringing one of us down.

As many of you know, Dan was an enthusiastic advocate of the Subaru engine and knew full well what he was getting into to I think. He offered his airframe up to Jan for the test program to validate the engine, propeller, gearbox, turbo, cooling and EM systems for several months and they flew the -10 to Oshkosh together earlier. Dan was a friend as well as a customer to Jan.

As David pointed out, there have been several Gen 1 and 2 gearbox failures over the years. They have shown generally good reliability on the atmo EJ25s to date. The Gen 3 is designed to replace those earlier boxes on the higher hp engines and Jan is recommending people upgrade to the stronger box. Seems reasonable with the better pieces now available and he is giving a price break. I view this similarly to the Van's nose gear thing and many other parts upgrades Van's has introduced over the years.

$50K Gearboxes fail on helicopters sometimes and I know that almost every brand of PSRU on the market has had issues or failures. We learn, we improve.

I gave up a month ago posting anything more on the auto vs. Lycoming debates as they are truly never ending and few people seem to care about what I say as someone who has some experience in the field. I can accept that. Let's just fly what interests us.

John, as I look back on your posts on various forums, clearly many of your posts seem directed in anger at Jan's business. You can have any opinion you want about anything you want of course. If this is your crusade so be it I guess.

Jan has made mistakes just as many of us have including Van's, Lycoming, Hartzell, MT, P-mag, IVO etc. The list is endless. Welcome to the human race. I think Jan is trying to make his products better and address known problem areas- nobody will be in business long otherwise. I don't think customers of earlier drives are happy about the new recommendations any more than any of us are when we have to spend money to upgrade something on our aircraft. You don't have to with experimentals of course.

I defend people like Jan because I come from the same field, not because I'm a supplier. To those who design, create, learn and fly their dreams, kudos. To those who hack at them, you'll garner little respect from me. It is so easy to criticize, much harder to do something that few others are doing. If you have a better way of doing something on your RV, share the knowledge here on VAF so that we all may benefit. I know I've learned a lot here.

Jan gives people a second powerplant choice for RVs, warts and all. While you may never buy one, hundreds of others have and like them. Dozens who have bought, don't like them just like many other products available to us. We are all adults here and have to cope with our decisions.

As long as we fly experimental, single engined aircraft there is some risk due to the relatively unproven systems many of us use and there are clearly still risks even using more proven assemblies as we have seen many times as well. The only way to ensure we won't be killed or injured flying is to never fly. I doubt if many of us including Dan would find that an acceptable solution.
__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 462.1 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
https://www.youtube.com/channel/UCiy...g2GvQfelECCGoQ



Last edited by rv6ejguy : 12-01-2007 at 11:29 AM.
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  #9  
Old 12-01-2007, 11:08 AM
allbee allbee is offline
 
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Location: spokane, wa
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My hats off to you guys.

You give the true meaning to Experiment... al aircraft.

As well as a true test pilot.

same goes for those that want the full glass panel.
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  #10  
Old 12-01-2007, 11:56 AM
David-aviator David-aviator is offline
 
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Quote:
Originally Posted by gmcjetpilot View Post
ha ha ha ha ha ha
George,

I am sure you love your dog but could you find a more flattering picture of it. He/she looks like he/she is spring loaded to bite. Is that item in its mouth a piece of someone's leg or what? I suppose it could be a ball.
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Last edited by David-aviator : 12-01-2007 at 11:59 AM.
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