X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mx1.magmacom.com ([206.191.0.217] verified) by logan.com (CommuniGate Pro SMTP 4.3.4) with ESMTPS id 986959 for flyrotary@lancaironline.net; Tue, 07 Jun 2005 01:35:14 -0400 Received-SPF: none receiver=logan.com; client-ip=206.191.0.217; envelope-from=ianddsl@magma.ca Received: from mail3.magma.ca (mail3.magma.ca [206.191.0.221]) by mx1.magmacom.com (8.13.0/8.13.0) with ESMTP id j575YR8Z031290 for ; Tue, 7 Jun 2005 01:34:28 -0400 Received: from binky (ottawa-hs-64-26-156-111.s-ip.magma.ca [64.26.156.111]) by mail3.magma.ca (8.13.0/8.13.0) with SMTP id j575YNAx029616 for ; Tue, 7 Jun 2005 01:34:27 -0400 Reply-To: From: "Ian Dewhirst" To: "Rotary motors in aircraft" Subject: Taking the liberty of reposting Jim's message with line feeds Date: Tue, 7 Jun 2005 01:34:11 -0400 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_007A_01C56B01.01BE8690" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.6604 (9.0.2911.0) In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 Importance: Normal This is a multi-part message in MIME format. ------=_NextPart_000_007A_01C56B01.01BE8690 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Jim's last message did not seem to work in Outlook, in case others have the same problem.... Jim Sower wrote: al p wick wrote: There are three components that define RISK. Most of your comments address only 1 of those, the failure rate. But that's the one you use to justify dismissing the parts count in a Soob. Yes, it's a little tough to nail the fail rate on the rotary engine. I think it's a LOT tough to nail down in ANY aviation application - Lyc, Soob, V6, whatever. The other two components have equal weight. What EFFECT the failed component will have on flight. How likely to notice the defect before flight. It's not too difficult to assess those two components accurately. Those two are the no-brainers. We don't need a lot of schooling to figure out that a single CAS is a show stopper, water or oil pump is a serious but manageable situation and Oil Pressure Switch a minor annoyance. So if we have the discipline to use these methods, we've got most of the risk equation nailed. I'm getting lost here. How does mastering the no-brainers but still largely clueless on failure rate get MOST of the equation nailed? Therefore, we don't have to be precise in defining the fail rate. We just have to do our best to be moderately objective. Which brings us right back where we started. Consequence and pre-flight detection are no-brainers. We can guess at the failure rates without seriously compromising the process. Our only remaining obstacle is to become moderately objective and we now have you to impart that skill to us. Can I be forgiven if I suggest that we already have one or two moderately objective souls amoungst us, and further, that we pretty much know who they are? But you know what this is essentially about? If we use our natural method What might this "natural method" look like? Would mine look a lot like or a lot different from yours or Cletus Johnson's? of determining risk, we make substantial judgement errors. You know what's worse, we don't have any feedback to tell us how wrong we are. Now I'm REALLY getting lost. Up until now, I thought we were (individually and collectively) up to our ass in feedback. Folks helpless to stop telling us how wrong we are. BOY! Was I ever reading this list wrong! We tend to put more emphasis on items from recent memory, like anecdotes we heard recently. We attach significance to emotional appeals. I'm thinkin' that part will vary a lot from one individual to another. For my own part, I've been drawing lessons from the blunders (real or imagined - but often fatal) of my brethren for upwards of forty years. I like to think there are a lot of rational, level headed individuals on this list. If there is a shortage of anything, I'd say it is of hysteria. It's difficult to realize these truths. The Japanese analyzed design judgement errors, and found if they followed the FMEA approach, there were fewer failures. No doubt. But getting back to the issue at hand, what did their data look like? Were they working with two legs of the stool out of three (no data)? Or did they have ALL their shit together? Here's an excellent example. I've seen people describe their reasoning for going rotary. Often I would hear: "It only has three moving parts, therefore it's safer". I suspect that 80% of you believed that. That is a gross error in perspective. No maybe, it's a huge distortion. But then again, maybe it's not. Maybe there's something important there. If it really IS a huge distortion, perhaps there's some readily available, compelling evidence to support that notion. It's a wonderful theory, it has a component of truth in it, but totally fails the tests for significance. This part (only my personal opinion) smells like one of those sweeping, unsupported generalities that my daddy warned me about. If a logical theory is not significant, you dump the theory. But first, you'd do well to have some really compelling evidence to support its insignificance. When you assess risk, at some point you have to look at the whole picture. Converting a rotary engine is extremely risky because there are so many creative activities you are doing. As opposed to converting to a ??? (Soob? V6? Inline-4? - you pick one) engine that is devoid of/has dramatically fewer creative activities? Each has many potential oversights, so the oversights occur. You have lot's of evidence that describes this. The ratio of dead sticks, the number of alarm conditions, whatever you choose. But you need the courage to face the truth. It's not easy. Now I won't argue that perhaps Soob or V6 has fewer dead-sticks per installation than rotarys (largely because I don't have the data to support such a position). Can we entertain the notion that some of this might involve: a) we (the rotary community) are operating much closer to the rated peak performance of our engines than, say, your Soob; b) we are eschewing critical factory components for what we feel are [potentially - key word here] superior, more robust custom components? I can understand that such activity would increase risk initially. The (widely held, I think) hope is that these efforts will produce a more robust, reliable fuel control (for example) that will advance the state of the art down the road. The goodness or folly of that notion rests with the individual IMO. Stipulating the added risk, I must point out that the significance of such risk (not by any means quattified at this stage) must be determined by the risk taker - not by som e umpire with a clip board. Now if we can take VERY effective action on those risk items, the ones we have all the failure data on? Or the ones we can inutit are obviously risky? then we have a power plant that has some real potential. Many of it's failure modes are gradual, thus reducing the EFFECT of the failure. Basically giving us more time to land safely. In theory, the rotary is less prone to torsional risks...although there are indications can you share some of those? that too fails the significance test. Unless we were to include Lycs with all their crankshaft ADs, or Ivo props, or gawd knows what we'd find if the Soobs and V6s were run at or above rated rpm. We get the satisfaction of being different and thumbing our noses at nay sayers. Any auto conversion qualifies here. We contribute to what can very likely be a viable alternative that exceeds Lycoming performance on all levels. And here too. So this guy that spent all those years looking into the root causes of failures, hopes he'll eventually be able to explain these things well enough, provide enough facts, that a life or two will be saved. I suppose that sounds corny, but that's my view. My view is that the pivotal aspect of his investigation was reliable failure data. Seems to me we can all pretty much agree that the rest is pretty intuitive and not at all difficult to master (even without taking night courses). -al wick On Mon, 06 Jun 2005 17:27:06 -0500 Jim Sower writes: <... in my book, redundancy is job one ...> The engine has demonstrated its ability to get you to the next airport without coolant or oil. Ignition and fuel are another matter. Dual EWPs might be necessary for TO and climb and redundant in cruise. Redundant oil pumps seem to me a whole lot more trouble than they're worth. As for CAS and the like, NAPA, dealerships etc. could provide the least UNreliable available as to what needs to be backed up and what doesn't. Might even discover that you need to back up the MAP sensor or something of the like before the CAS on account of they fail all the time. My point is: *who knows??* In my view, Al's discipline and methodology work beautifully in a factory where the same machines are doing the same thing hundreds of thousands of times a day. It works less well for say, cars because it's so much more difficult to gather accurate data. How you gonna determine how many of some component failed after how much use? Dealerships are a help - they track what failed and when - but the independent shops do not and I'm pretty sure they do the great bulk of the repair business. On top of not knowing with any degree of reliability what failed and when, we are totally clueless as to fleet mileage. Therefore MTBF is impossible to track unless you assume (remember that acronym) that the fraction of data gleaned from dealerships reflects the entire fleet accurately. Bit of a stretch IMO. So here we are examining airplanes. Homebuilts no less. How in hell on earth are you gonna' get data around failures? Al got his little slice off the Canard or Cozy list(s), but it was a *tiny* slice of reality submitted by volunteers. Just for openers, I'd have to question the *motives* of the guys who participated in his little study - and the guys who *didn't* as well. Beyond participants' agenda, the small size of the sample is troubling. If one could identify all of the suppliers of parts and components, one might estimate MTBF of this component relative to that component, but life expectancy in actual hours is still an impossible dream. Add to that the fact that Lycs on planes that fly all the time (like instruction, air freight, air taxi and the like) almost always make it to TBO while the same engines on privately owned, rarely flown planes almost never do. Quantify *that* Tarzan! Does that phenomenon apply to auto conversions too? Does it matter? Damned if I know. I may be mistaken here, but it seems to me that the very soul of Al's methodology is accurate data around the incidence of failures. He can speak to that better than I can, and I sure hope he does. Additionally, only he can speak to the degree to which data that is dirty and/or unreliable skews the results. Basically, it seems to me that Al is trying to quantify something that's qualitatively intuitive to everyone on the list. We can guess which components need attention and set rough priorities as to which ones to address first. The main issue is quantifying these occurrences failure. At this juncture Al simply does not have the data to do this with a lot better reliability than we could do with educated guesses. He needs a *lot* of *good* data IMO. I'm wondering if it's possible that he will ever get it ... Jim S. ------------------------------------------------- Was said ... I see guys doubling up on water pumps (2 EWP in some cases) yet because there hasn't been a CAS failure (that we know of) they are not worried . If you want true redundancy, you must double up on the systems that have a possibility of killing you engine (and you,no matter how remote) The CAS failure could be between the ECU & the CAS due to our application. Not to be too critical, but I've seen some pretty scary (sloppy) installations. If you follow the certificated aircraft procedures as far as securing, protecting & routing wires, hoses, pipes & components you can be on your way to a safe installation. Georges B. (in my book, redundancy is job one) and ... I fail to see how installing another CAS will 'dramatically' reduce risk of all ECM causes. We have already said we have no history of failure of the CAS, how can installing another CAS (with no history of failure), 'dramatically' reduce the risk of failure? And how can installing another CAS have any influence on "the risk of all ECM causes" ? I also have great respect for redundant systems, but I cannot see your logic in this one. It is the 'dramatic reduction' that troubles me. Homepage: http://www.flyrotary.com/ Archive: http://lancaironline.net/lists/flyrotary/List.html -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 Homepage: http://www.flyrotary.com/ Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_007A_01C56B01.01BE8690 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Jim's last message did not seem = to work in=20 Outlook, in case others have the same=20 problem....

Jim Sower=20 wrote:

al p wick wrote:

There are three components that define RISK. Most of your = comments address only 1 of those, the failure = rate. But that's the one you use to justify dismissing the = parts count=20 in a Soob. Yes, it's a little tough to nail the fail rate on the = rotary=20 engine. I think it's a LOT tough to nail down in = ANY=20 aviation application - Lyc, Soob, V6, whatever. The other two = components=20 have equal weight. What EFFECT the failed component will have on flight. = How=20 likely to notice the defect before flight. It's not too difficult to = assess=20 those two components accurately. Those two are the = no-brainers. We don't need a lot of schooling to figure out that a = single CAS is=20 a show stopper, water or oil pump is a serious but manageable situation = and Oil=20 Pressure Switch a minor annoyance. So if we have the discipline = to use=20 these methods, we've got most of the risk equation nailed. I'm getting lost here. How does mastering the = no-brainers but=20 still largely clueless on failure rate get MOST of the equation = nailed?=20 Therefore, we don't have to be precise in defining the fail rate. We = just have=20 to do our best to be moderately objective. Which = brings us=20 right back where we started. Consequence and pre-flight detection are=20 no-brainers. We can guess at the failure rates without seriously = compromising=20 the process. Our only remaining obstacle is to become moderately = objective and=20 we now have you to impart that skill to us. Can I be forgiven if I = suggest that=20 we already have one or two moderately objective souls amoungst = us, and=20 further, that we pretty much know who they are?

But you know what this is essentially about? If we use our natural = method=20 What might this "natural method" look like? Would = mine look=20 a lot like or a lot different from yours or Cletus Johnson's? of=20 determining risk, we make substantial judgement errors. You know

what's worse, we don't have any feedback to tell us how wrong we are. = Now I'm REALLY getting lost. Up until now, I thought we = were=20 (individually and collectively) up to our ass in feedback. Folks=20 helpless to stop telling us how wrong we are. BOY! Was I ever = reading=20 this list wrong! We tend to put more emphasis on items from = recent=20 memory, like anecdotes we heard recently. We attach significance to = emotional=20 appeals. I'm thinkin' that part will vary a lot = from one=20 individual to another. For my own part, I've been drawing lessons from = the=20 blunders (real or imagined - but often fatal) of my brethren for upwards = of=20 forty years. I like to think there are a lot of rational, level headed=20 individuals on this list. If there is a shortage of anything, I'd say it = is of=20 hysteria. It's difficult to realize these truths. The Japanese = analyzed=20 design judgement errors, and found if they followed the FMEA approach, = there=20 were fewer failures. No doubt. But getting back to = the issue=20 at hand, what did their data look like? Were they working with two legs = of the=20 stool out of three (no data)? Or did they have ALL their shit=20 together?

Here's an excellent example. I've seen people describe their = reasoning

for going rotary. Often I would hear: "It only has three moving = parts,

therefore it's safer". I suspect that 80% of you believed that. That = is a=20 gross error in perspective. No maybe, it's a huge distortion. But then again, maybe it's not. Maybe there's something = important=20 there. If it really IS a huge distortion, perhaps there's some readily=20 available, compelling evidence to support that notion. It's a

wonderful theory, it has a component of truth in it, but totally = fails

the tests for significance. This part (only my = personal=20 opinion) smells like one of those sweeping, unsupported generalities = that my=20 daddy warned me about. If a logical theory is not significant, = you dump=20 the theory. But first, you'd do well to have some = really=20 compelling evidence to support its insignificance.

When you assess risk, at some point you have to look at the whole

picture. Converting a rotary engine is extremely risky because there = are

so many creative activities you are doing. As = opposed to=20 converting to a ??? (Soob? V6? Inline-4? - you pick one) engine that is = devoid=20 of/has dramatically fewer creative activities? Each has many=20 potential

oversights, so the oversights occur. You have lot's of evidence = that

describes this. The ratio of dead sticks, the number of alarm = conditions,=20 whatever you choose. But you need the courage to face the truth. It's = not easy.=20 Now I won't argue that perhaps Soob or V6 has = fewer=20 dead-sticks per installation than rotarys (largely because I don't have = the data=20 to support such a position). Can we entertain the notion that some of = this might=20 involve: a) we (the rotary community) are operating much closer to the = rated=20 peak performance of our engines than, say, your Soob; b) we are = eschewing=20 critical factory components for what we feel are [potentially - key word = here]=20 superior, more robust custom components? I can understand that such = activity=20 would increase risk initially. The (widely held, I think) hope is that = these=20 efforts will produce a more robust, reliable fuel control (for example) = that=20 will advance the state of the art down the road. The goodness or folly = of that=20 notion rests with the individual IMO. Stipulating the added risk, I must = point=20 out that the significance of such risk (not by any means quattified at = this=20 stage) must be determined by the risk taker - not by som

e umpire with a clip board.

Now if we can take VERY effective action on those risk items, the ones we have all the failure data on? Or the ones we = can=20 inutit are obviously risky? then we have a power plant that has = some real=20 potential. Many of it's failure modes are gradual, thus reducing the = EFFECT of=20 the failure. Basically giving us more time to land safely. In theory, = the rotary=20 is less prone to torsional risks...although there are indications can you share some of those? that too fails the=20 significance test. Unless we were to include Lycs = with all=20 their crankshaft ADs, or Ivo props, or gawd knows what we'd find if the = Soobs=20 and V6s were run at or above rated rpm. We get the satisfaction = of being=20 different and thumbing our noses at nay sayers. Any auto=20 conversion qualifies here. We contribute to what can very likely = be a=20 viable alternative that exceeds Lycoming performance on all levels. = And here too.

So this guy that spent all those years looking into the root causes = of

failures, hopes he'll eventually be able to explain these things = well

enough, provide enough facts, that a life or two will be saved. I = suppose=20 that sounds corny, but that's my view. My view is = that the=20 pivotal aspect of his investigation was reliable failure data. Seems to = me we=20 can all pretty much agree that the rest is pretty intuitive and not at = all=20 difficult to master (even without taking night = courses).

-al wick

On Mon, 06 Jun 2005 17:27:06 -0500 Jim Sower <canarder@frontiernet.net>

writes:

<... in my book, redundancy is job one ...>

The engine has demonstrated its ability to get you to the next

airport

without coolant or oil. Ignition and fuel are another matter. Dual =

EWPs might be necessary for TO and climb and redundant in cruise. =

Redundant oil pumps seem to me a whole lot more trouble than they're =

worth.

As for CAS and the like, NAPA, dealerships etc. could provide the =

least

UNreliable available as to what needs to be backed up and what

doesn't. Might even discover that you need to back up the MAP

sensor or

something of the like before the CAS on account of they fail all the =

time. My point is: *who knows??*

In my view, Al's discipline and methodology work beautifully in a =

factory where the same machines are doing the same thing hundreds of =

thousands of times a day. It works less well for say, cars because =

it's

so much more difficult to gather accurate data. How you gonna

determine

how many of some component failed after how much use? Dealerships =

are a

help - they track what failed and when - but the independent shops =

do

not and I'm pretty sure they do the great bulk of the repair

business.

On top of not knowing with any degree of reliability what failed and =

when, we are totally clueless as to fleet mileage. Therefore MTBF =

is

impossible to track unless you assume (remember that acronym) that =

the

fraction of data gleaned from dealerships reflects the entire fleet =

accurately. Bit of a stretch IMO.

So here we are examining airplanes. Homebuilts no less. How in

hell on

earth are you gonna' get data around failures? Al got his little

slice

off the Canard or Cozy list(s), but it was a *tiny* slice of reality =

submitted by volunteers. Just for openers, I'd have to question the =

*motives* of the guys who participated in his little study - and the =

guys who *didn't* as well. Beyond participants' agenda, the small =

size

of the sample is troubling. If one could identify all of the

suppliers

of parts and components, one might estimate MTBF of this component =

relative to that component, but life expectancy in actual hours is =

still

an impossible dream. Add to that the fact that Lycs on planes that =

fly

all the time (like instruction, air freight, air taxi and the like) =

almost always make it to TBO while the same engines on privately

owned,

rarely flown planes almost never do. Quantify *that* Tarzan! Does =

that

phenomenon apply to auto conversions too? Does it matter? Damned

if I

know.

I may be mistaken here, but it seems to me that the very soul of

Al's

methodology is accurate data around the incidence of failures. He =

can

speak to that better than I can, and I sure hope he does.

Additionally,

only he can speak to the degree to which data that is dirty and/or =

unreliable skews the results. Basically, it seems to me that Al is =

trying to quantify something that's qualitatively intuitive to

everyone

on the list. We can guess which components need attention and set =

rough

priorities as to which ones to address first. The main issue is

quantifying these occurrences failure. At this juncture Al simply =

does

not have the data to do this with a lot better reliability than we =

could

do with educated guesses. He needs a *lot* of *good* data IMO.

I'm wondering if it's possible that he will ever get it ... Jim = S.

-------------------------------------------------

Was said ...

I see guys doubling up on water pumps (2 EWP in some cases) yet

because

there hasn't been a CAS failure (that we know of) they are not

worried .

If you want true redundancy, you must double up on the systems that =

have

a possibility of killing you engine (and you,no matter how remote) =

The

CAS failure could be between the ECU & the CAS due to our

application.

Not to be too critical, but I've seen some pretty scary (sloppy)

installations. If you follow the certificated aircraft procedures as =

far

as securing, protecting & routing wires, hoses, pipes & = components=20

you

can be on your way to a safe installation.

Georges B. (in my book, redundancy is job one)

and ...

I fail to see how installing another CAS will 'dramatically' = reduce

risk of all ECM causes.

We have already said we have no history of failure of the CAS, how =

can

installing another CAS (with no history of failure), = 'dramatically'

reduce the risk of failure?

And how can installing another CAS have any influence on "the risk =

of

all ECM causes" ?

I also have great respect for redundant systems, but I cannot see =

your

logic in this one. It is the 'dramatic reduction' that troubles = me.

 

 

Homepage: http://www.flyrotary.com/

Archive: http://lancaironline.net/lists/flyrotary/List.html

 

-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

Homepage: http://www.flyrotary.com/

Archive: http://lancaironline.net/lists/flyrotary/List.html

 

 

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