X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 04 Jun 2008 10:10:34 -0400 Message-ID: X-Original-Return-Path: Received: from mail08.syd.optusnet.com.au ([211.29.132.189] verified) by logan.com (CommuniGate Pro SMTP 5.2.3) with ESMTPS id 2952793 for lml@lancaironline.net; Wed, 04 Jun 2008 08:14:10 -0400 Received-SPF: pass receiver=logan.com; client-ip=211.29.132.189; envelope-from=fredmoreno@optusnet.com.au Received: from fred ([202.139.5.198]) (authenticated sender fredmoreno) by mail08.syd.optusnet.com.au (8.13.1/8.13.1) with ESMTP id m54CCxXw022837; Wed, 4 Jun 2008 22:13:10 +1000 From: "Fred Moreno" X-Original-To: "Lancair Mail" X-Original-Cc: "'George Braly'" Subject: [LML] Re: Sparking plugs DIALOG X-Original-Date: Wed, 4 Jun 2008 20:13:02 +0800 X-Original-Message-ID: <007d01c8c63c$5f15c9e0$c6058bca@fred> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_007E_01C8C67F.6D3909E0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6822 Importance: Normal Thread-Index: AcjGKu/Nmzy1IipNQPWl8xf2Da5RuwACcJyw X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 This is a multi-part message in MIME format. ------=_NextPart_000_007E_01C8C67F.6D3909E0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable George:=20 =20 Many thanks for your comments which I found to be very helpful.=20 =20 I want to continue this dialog and have added more material below to continue the Q and A. My replies are in green. But first I want to = make a big picture observation.=20 =20 Certified engines have well defined operating envelopes based on = extensive testing, technical knowledge, and millions of hours of field experience. Buyers deserve that depth of knowledge because they did not sign up to = be test pilots.=20 =20 Experimental engines and aircraft have an overt statement of increased = risk - the sign that says "Experimental." So in experimental, we are all = test pilots to an extent. Your implication is that because we do not fully = test, document, and frequently do not understand changes we make, we should = not make those changes. But we are not GAMI or Continental or Lycoming. We = do not have the resources to do that kind of testing, and therefore have to = be less knowledgeable. =20 =20 But we love to fly and experiment. That is the nature of our hobby. It = is not the nature of Cessna, Piper, et al.=20 =20 Your objection is in effect that we should not experiment because we do = not know the new limits of operation and therefore take on additional risk = when we operate without this knowledge.=20 =20 But we (should) know we are taking extra risks. =20 =20 The problem is that many in the experimental community do not = acknowledge the risk, and more important do not know when they are creating extra = risk. =20 As an engineer I agree with your assessment about distinguishing between knowns and unknowns. As an experimental enthusiast, I welcome the = option to experiment, but I try to do so with care and understanding. We all = need to continually improve this understanding. That is why this forum is = important and useful.=20 =20 Ultimately it all depends on your world view and willingness to take responsibility for your actions. But that is another topic.=20 =20 I'll get off this soap box with two suggestions for all of us: "Get thee understanding." "Understand Increased Risk." =20 Now, to improve understanding, let's continue the dialog =20 INDUCTION AIR TEMPERATURE. That one is OFTEN badly overlooked and it = is a major driver WRT detonation.=20 =20 Thanks for highlighting. It is an excellent warning for the turbo guys, = and for those of us who operate from cold to very hot climates. Make adjustments in your engine operating habits when induction air = temperatures climb. =20 Hot plugs are almost exclusively a pre-ignition issue, not a detonation issue. But then pre-ignition is a much uglier thing than detonation. =20 Thanks for the correction. Does one then run as cold a plug as possible while avoiding plug fouling? =20 The problem is that I have NEVER seen an experimental aircraft that had properly defined that "smaller envelope" with appropriate markings and limitations on the instrument panel. =20 =20 I agree. So I think the best benefit is for experimental guys with = modified engines to recognize that while they do not know how much smaller their envelope may be, it will be smaller and they should act accordingly. I don't know how fast my car can take a particular corner (I am not a = racer), but stock or modified, wet or dry road, I know to drive conservatively = if I do not want to bend the car. =20 =20 =20 But WHERE are the boundaries of that envelope??? =20 Unfortunately most of us will never know, but we should recognize that = the boundaries are NOT same as for the certified engine. So I would assert = that if you modify your engine, DO NOT to try to go to the certified limits = of (for example) CHT. I wish I knew what was appropriate for my engine, = but I don't. But I do know I should be conservative on MAP, Temperature, and Mixture. I am. And I know I am experimenting and taking some risk in = so doing. It was my choice. I hope it was informed.=20 =20 - and thus they continue to operate with the "hope" (not a = method) that they will be "OK". =20 =20 This brought a smile. Once while wandering around OSH, Brent Regan and = I formulated a theory. The Greeks believed that all matter in the = universe was made up of Earth, Air, Fire and Water. At OSH, we concluded that = the local world was made up of Hope, Denial (of the laws of physics), Money, = and Bullshit. So I guess I agree with you.=20 =20 It is reasonable only in the context of two further constraints: - - = the owners really do want to be "experimental test pilots" =20 Here we come full circle. By definition in experimental they ARE test pilots. The question is whether or not they recognize it.=20 =20 and they are comfortable with hoping that they have fully explored the relevant envelope. Without the instrumentation and tests, how can they except to rely on guys like you, honest vendors, and their own understanding? =20 Two questions: =20 1) What benefit to you think you get from the 10:1 CR ? Better fuel economy. I estimated maybe 6% better compared to 8.5:1 CR, but the dyno data from a reliable source (and relayed to me by Doug Brunner as I = recall) suggests that 310 HP is raised to maybe 325, corrected, or an = improvement of maybe 5% in the real world. That is $4 an hour at cruise where I = operate. Full disclosure - as an old engineer, I now place more merit on = efficiency than raw speed.=20 =20 2) Have you marked your CHT with a redline at some number below 460 d F? Absolutely YES. I am not sure what the right number is, but as you may = know, I am a fanatic about cooling and cooling drag. I have an engine monitor with a Bitching Betty on yellow and red bands, and she starts bitching = at 350F (bottom of yellow, where I am reminded to take corrective action) = and she gets serious at 400F which I recently reset as bottom of the red. I = try to run at 320F and below, particularly during take off and high power = climb. I know those high compression pistons need extra attention. I watch = very closely, particularly in light of GAMI suggestions and this very = discussion. =20 Let the education process continue! =20 Regards,=20 =20 Fred, AKA Captain Tuna, Chicken of the Skies =20 =20 =20 ------=_NextPart_000_007E_01C8C67F.6D3909E0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

George:

 

Many thanks for your comments = which I found to be very helpful.

 

I want to continue this dialog and = have added more material below to continue the Q and A.  My replies are = in green.  But first I want to make a big picture observation.

 

Certified= engines have well defined operating envelopes based on extensive testing, = technical knowledge, and millions of hours of field experience.  Buyers = deserve that depth of knowledge because they did not sign up to be test = pilots.

 

Experimental engines and aircraft have an overt statement of increased risk – the sign that = says “Experimental.”  So in experimental, we are all test pilots to an extent.  Your = implication is that because we do not fully test, document, and frequently do not understand changes we make, we should not make those changes.  But = we are not GAMI or Continental or Lycoming.  We do not have the resources = to do that kind of testing, and therefore have to be less knowledgeable.  =

 

But we love to fly and = experiment.  That is the nature of our hobby.  It is not the nature of Cessna, Piper, = et al.

 

Your objection is in effect that = we should not experiment because we do not know the new limits of operation = and therefore take on additional risk when we operate without this = knowledge.

 

But we (should) know we are taking = extra risks. 

 

The problem is that many in the experimental community do not acknowledge the risk, and more important = do not know when they are creating extra risk.  

 

As an engineer I agree with your assessment about distinguishing between knowns and unknowns.  As an experimental enthusiast, I welcome the option to experiment, but I try = to do so with care and understanding.   We all need to continually = improve this understanding.  That is why this forum is important and = useful.

 

Ultimately it all depends on your = world view and willingness to take responsibility for your actions.  But = that is another topic.

 

I’ll get off this soap box = with two suggestions for all of us: “Get thee understanding.”  = “Understand Increased Risk.”

 

Now, to improve understanding, = let’s continue the dialog

 

INDUCTION AIR = TEMPERATURE.   That one is OFTEN badly overlooked and it is a major driver WRT detonation. 

 

Thanks for highlighting.  It = is an excellent warning for the turbo guys, and for those of us who operate = from cold to very hot climates.   Make adjustments in your engine = operating habits when induction air temperatures climb.

 

 Hot plugs are almost exclusively a pre-ignition issue, not a detonation issue.   = But then pre-ignition is a much uglier thing than = detonation.

 

Thanks for the correction.  = Does one then run as cold a plug as possible while avoiding plug = fouling?

 

The problem is that I have NEVER = seen an experimental aircraft that had properly defined that "smaller envelope" with appropriate markings and limitations on the = instrument panel.  

 

I agree.  So I think the best benefit is for experimental guys with modified engines to recognize that = while they do not know how much smaller their envelope may be, it = will be smaller and they should act accordingly.  I don’t know = how fast my car can take a particular corner (I am not a racer), but stock or = modified, wet or dry road, I know to drive conservatively if I do not want to bend = the car.   

 

 

But WHERE are the boundaries of = that envelope???

 

Unfortunately most of us will = never know, but we should recognize that the boundaries are NOT same as for the = certified engine.  So I would assert that if you modify your engine, DO NOT = to try to go to the certified limits of (for example) CHT.   I wish I = knew what was appropriate for my engine, but I don’t.  But I do = know I should be conservative on MAP, Temperature, and Mixture.  I = am.  And I know I am experimenting and taking some risk in so doing.   = It was my choice.  I hope it was informed.

 

-          and thus they = continue to operate with the "hope"  (not a method)  that they will be  "OK".   

 

This brought a smile.  Once = while wandering around OSH, Brent Regan = and I formulated a theory.  The Greeks believed that all matter in the = universe was made up of Earth, Air, Fire and Water.  At OSH, we concluded that the local world was made up of Hope, Denial (of the laws = of physics), Money, and Bullshit.  So I guess I agree with you. =

 

It is reasonable only in the = context of two further constraints:   - - the owners really do want to be "experimental test pilots" 

Here we come full circle.  By definition in experimental they ARE test pilots.  The question is = whether or not they recognize it.

 

and they are comfortable with = hoping that they have fully explored the relevant envelope.  Without the instrumentation and = tests, how can they except to rely on guys like you, honest vendors, and their = own understanding?

 

Two questions:

 

1) What benefit to you think you get from the 10:1 CR ?    Better fuel economy.  I estimated maybe 6% better compared to 8.5:1 CR, but the = dyno data from a reliable source (and relayed to me by Doug Brunner as I recall) = suggests that 310 HP is raised to maybe 325, corrected, or an improvement of = maybe 5% in the real world.  That is $4 an hour at cruise where I = operate.  Full disclosure – as an old engineer, I now place more merit on = efficiency than raw speed.

 

2) Have you marked your CHT with a redline at some = number below 460 d F?   Absolutely YES. I am not sure what the right number is, but as you may know, I am a fanatic about cooling and cooling drag.  I have an engine monitor = with a Bitching Betty on yellow and red bands, and she starts bitching at 350F = (bottom of yellow, where I am reminded to take corrective action) and she gets = serious at 400F which I recently reset as bottom of the red.  I try to run = at 320F and below, particularly during take off and high power climb. =   I know those high compression pistons need extra attention.  I watch = very closely, particularly in light of GAMI suggestions and this very = discussion.

 

Let the education process = continue!

 

Regards,

 

Fred, AKA Captain Tuna, Chicken of = the Skies

 

 

 

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