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Date: Mon, 06 Jun 2005 16:29:58 -0500
From: Jim Sower <canarder@frontiernet.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: EC2 problems - solved / rotary risks
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<... hard to have redundancy on timing belts ...>
What happened to the steel timing chains of yore?  Lynn?   Leon?  They 
didn't seem to *need* to be redundant (or replaced every 60k mi).

A little ($400?) capital intensive, but takes the main failure mode off 
the table ... Jim S.

Echo Lake Fishing Resort (Georges Boucher) wrote:

> On the other hand when I had my shop I found that the biggest cause of 
> belt failure was belt tensioner bearing seizing up usually after the 
> first belt was replaced(even though the tensioner felt free the sealed 
> bearings had dried up) In my opinion the tensioner(s) should be 
> replaced at the same tine as the belt(s) . One that sticks to mind was 
> a Peugeot MY16 twin cam, the customer didn't go for the $100.00 + 
> tensioner , 4000km later had $3000.00 rebuild (valve to piston contact 
> at high rpm). It's pretty hard to have redundancy on timing belts, I 
> like the odds with a rotary!!
> Georges B.
>  
> /-------Original Message-------/
>  
> /*From:*/ Rotary motors in aircraft <mailto:flyrotary@lancaironline.net>
> /*Date:*/ 06/06/05 08:50:33
> /*To:*/ Rotary motors in aircraft <mailto:flyrotary@lancaironline.net>
> /*Subject:*/ [FlyRotary] Re: EC2 problems - solved / rotary risks
>  
> Hi Al,
>  
> The timing belt risk on your Subaru may be lower then you think, in my 
> experience timing belt failures occur at engine start 9 times out of 
> 10.  Most Japanese manufacturers recommend a replacement interval of 
> about 70,000 miles, if the oil seals are replaced at the same time and 
> the belt is re-tensioned after the first heat cycle you should be 
> quite safe. 
>  
> Ian
>  
> (Convinced that you are NOT flying the highest risk aircraft ever made ;-)
> -----Original Message-----
> *From:* Rotary motors in aircraft 
> [mailto:flyrotary@lancaironline.net]*On Behalf Of *al p wick
> *Sent:* Monday, June 06, 2005 9:58 AM
> *To:* Rotary motors in aircraft
> *Subject:* [FlyRotary] Re: EC2 problems - solved / rotary risks
>
> When we are pursuing a problem like Johns, we are eager to find the 
> cause. It's a great relief when we do. We say "Eureka!". We did it! We 
> did it! This sense of relief is a root cause for failure. We are so 
> eager to get the problem off our back, that we don't take the next 
> step....
> Yes, I know you firmly believe this connector was the problem. But if 
> you can force yourself to pretend it WASN'T, then you can do this:
> Is the cause logical? Like is that really the wire that causes that 
> effect? If I remove that wire, does it have the same effect? What if I 
> have two things causing the same thing? By pretending that really 
> wasn't the cause, then you will do some more testing, looking around. 
> Looking for similar connector issues, stuff like that.
>  
> Now I have to admit, this really does sound like he found the cause. 
> But I've seen this scenario so often. So you use the disciplines I 
> suggest to reduce your risk. Logical cause? Can I make it recur?
> Repeat after me: "Al Wick is an idiot". "Al will jump to conclusions". 
> If you believe that, then you start finding ways to prove your 
> theory with facts instead of just accepting your first conclusion. My 
> best asset is that I know I'm an idiot.
>  
> Yeah, yeah, I know, you guys already knew I was.
>  
> We had a perfect example of this on Cozy list couple weeks ago. Subaru 
> engine slipped 2 teeth on timing belt. Would no longer start. Keith 
> talked to expert and the guy said:"You know, the engine normally is 
> never rotated backwards. But you've been pushing your new prop 
> backwards recently (installing new prop). I think you relaxed the belt 
> tensioner when going backwards and caused it to skip tooth." So Keith 
> said" Yes, all of that's true. That has to be it."
>  
> But then one of the guys looked into it, guess what? The direction the 
> belt slipped is the opposite of that theory. That could not have 
> caused it.
> The lesson? Prove all aspects of the theory are logical. Prove that 
> all the various facts support the theory. Find a way to convert your 
> theory to facts!
>  
> Oh, by the way, if you look at my analysis of my engine risks....you 
> will notice that timing belt is the highest risk item on this engine. 
> So we have exposed another root cause for his problem. He didn't focus 
> on the leading cause for all engine failures. When we reviewed some 
> facts he had, we found conclusive evidence he had loose belt from day 
> one! It was installed wrong.
>  
> Regarding CAS risk. It's not just crank angle sensor that is the risk 
> item. Going to redundancy with the CAS will dramatically reduce risk 
> of all ECM causes. Like this connector risk. I'm not always proponent 
> of redundancy, but with my limited info on this item, I SUSPECT it's 
> significant, positive step.
>
> -al wick
> Artificial intelligence in cockpit, Cozy IV powered by stock Subaru 2.5
> N9032U 200+ hours on engine/airframe from Portland, Oregon
> Prop construct, Subaru install, Risk assessment, Glass panel design info:
> http://www.maddyhome.com/canardpages/pages/alwick/index.html
>  
>  
>  
> On Sun, 5 Jun 2005 21:44:00 -0400 "Tracy Crook" <lors01@msn.com 
> <mailto:lors01@msn.com>> writes:
> *Ahh..  Music to my ears John : )*
> ** 
> *And this brings up the subject of risk (rotary & otherwise) that Al 
> W. (and every other builder I know) is concerned with.  I agree with 
> Al W. that getting to the major causes of failures is a (hell, THE) 
> key issue.  That is why I have not spent much time on the crank angle 
> sensor single point failure question.  I have never seen or heard of a 
> confirmed Mazda 13B CAS failure.  Can it happen?  Of course.  I am in 
> the process of developing a dual CAS for the Renesis CAS but it is not 
> a 'front burner' project.*
> ** 
> *I'm reading between the lines of Al's posts but it seems that he is 
> emphasizing the importance of leaving the engine as un-touched as 
> possible.  I once wrote an article for Light Plane World (EAA's 
> ultralight magazine back in the late 80's) and advocated the same 
> thing after noting that many Rotax failures  occurred soon after the 
> owner opened up the engine for maintenance.  Decarboning the piston 
> ring grooves was important but many builders were causing more 
> problems than they fixed when they went inside so I recommended some 
> products and procedures that would do the job without opening the 
> engine.  *
> ** 
> * That was the basic gist anyway but I eventually decided this was not 
> a reasonable approach for builders who planned on installing an 
> alternative engine in 200 mph category airplanes.  There were simply 
> far too many areas where things could go wrong in this process.  The 
> root cause of the problems had to be identified.   One of the names I 
> gave to the cause is a term I recently used on this list - Shopcraft 
> (or lack of).   This referred to the ability to identify the quality 
> or suitability of virtually everything that goes into the plane.  Yes, 
> I know this is a generality of the highest order but if we are to get 
> to the root cause of failures in the field of alternative aircraft 
> engines, this level of abstraction is required.  *
> ** 
> *It has been suggested that a collection of 'best practices' might be 
> a solution.  This may help but it is not a solution.  There is an 
> unlimited number of potential problem areas so a list of them could 
> never be compiled.   So, how do you learn to recognize what is or is 
> not a 'good thing'?   I'm getting so frustrated just trying to 
> describe the problem that there may not be a solution, at least not 
> one that can be spelled out in something like an email 
> message.   Damn, now I can't even criticize Al W. for not spelling it 
> out. *
> ** 
> *The best I can do for now is to emphasize two things.  Pay attention 
> to every detail and admit to yourself when you don't have the ability 
> to execute something well.   Another version of these rules was given 
> to me long ago:*
> ** 
> *1.  Rules are for those who are not smart enough to make up their 
> own.  (Author unknown)*
> *2.  A man's got to know his own limitations.  (Dirty Harry)*
> *3.  Always follow BOTH rules 1 & 2.*
> ** 
> *Small details like the problem of soldering thermocouple wire to a 
> connector that Al Gietzen mentioned can be critically important.  He 
> was able to recognize the problem (he made a lousy solder joint) and 
> devise a solution (acid flux) even though it violated one of the 
> cardinal rules of electrical wiring.  He recognized that too and took 
> the steps necessary to achieve satisfactory results (knowing when to 
> make up his own rules).*
> ** 
> *Out of time, I'll stop blathering now.*
> ** 
> *Tracy  *
>  
> *Subject:* [FlyRotary] EC2 problems - solved
>
> Tracy and others.
> Following more than 12 months of battling with EC2 issues I'm pretty 
> sure it's Eureka day!
> After rewiring and testing for almost 4 weeks I plugged the EC2 in 
> last night, and got exactly the same symptoms as before. NOP flashing 
> indicating no communication. I took the EC2 to Buly's plane and tried 
> it in his installation. Same NOP, so I was thinking I'd fried it 
> again. Before sending it back yet again I decided to install it my 
> plane one more time and see if there was a spark.
>  
> To my amazement it worked. No NOP, and I could bring up the EC2 data. 
> The only thing that changed overnight was that I moved the cable to 
> unplug it. I climbed in the back and found that I could make the NOP 
> flash, or stop flashing, by moving the cable. I haven't taken the 
> connector apart yet, but I'm expecting to find a broken wire inside 
> the insulation, probably near a solder joint at the pin. Whenever I 
> bent the connector outward for testing it made contact. When I bent it 
> back to plug it in, contact was lost.
>  
> Bingo!
> John
>  
> Just guessing, but maybe the new EC2 can't communicate with a 
> pre-autotune EM2 like Buly's. ???
>  
>  
>
> 	
> 	
>
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