X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.122] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with ESMTP id 5107131 for flyrotary@lancaironline.net; Mon, 29 Aug 2011 10:38:43 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.122; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=1.1 cv=clOQl2Kon9ihL0vqe5S6shCOWnQ8eDPHG/StQ1omz74= c=1 sm=0 a=yXptfsiEyrQA:10 a=SC71y0a/4S6V9vjVxUojGA==:17 a=ayC55rCoAAAA:8 a=OBoQRNBVAAAA:8 a=N8B9JuSIAAAA:8 a=ilbRnJSluC4b07VW9G8A:9 a=9Vou9m7Xei0-2PS9kBwA:7 a=wPNLvfGTeEIA:10 a=pYEayob8caUA:10 a=GZfqqOgijK-zI-UM:21 a=p5ypZyiuwqd0aKwP:21 a=Ia-xEzejAAAA:8 a=pGLkceISAAAA:8 a=YfKzPtlLw1Yxz-4YDkcA:9 a=j9x-Ns5BYOCQqeaa7QIA:7 a=EzXvWhQp4_cA:10 a=MSl-tDqOz04A:10 a=SC71y0a/4S6V9vjVxUojGA==:117 X-Cloudmark-Score: 0 X-Originating-IP: 174.110.175.135 Received: from [174.110.175.135] ([174.110.175.135:51394] helo=EdPC) by cdptpa-oedge01.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id F4/35-15370-054AB5E4; Mon, 29 Aug 2011 14:38:08 +0000 Message-ID: From: "Ed Anderson" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Freq analysis of Knock sensor? Date: Mon, 29 Aug 2011 10:36:02 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0009_01CC6637.72B15340" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 This is a multi-part message in MIME format. ------=_NextPart_000_0009_01CC6637.72B15340 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable A thought occurred to me. If anyone has a spectrum analyzer (Steve??) = and could obtain an Rotary Knock sensor - that perhaps determining the = frequency response of the knock sensor MIGHT indicate the frequency band = pass required. Although it is likely to be too broad to be much help if = ( as likely) they do the filtering through a bandpass filter within the = engine CPU. Ed From: Ed Anderson=20 Sent: Monday, August 29, 2011 9:54 AM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Not so Simple was Knock sensor was tune with ADI: = [FlyRotary] Re: How to tune with ADI? As Tracy also indicated - in may cases, what initially appears simple - = frequently turns out not to be the case, when you dive into the = details.=20 Another seemingly simple project I thought about, was to add a wide band = O2 (WBO2) sensor option for the EFISM. This in order to provide more = accurate info on the air/fuel ratio (although one could argue just how = useful that might be for our applications). =20 While providing an algorithm for the different voltage input curve of = the WBO2 sensor (it is much more linear than the narrow band O2 sensor = curve) is straightforward, when you dive deeper you discover that: 1. For the wide band O2 sensor to provide accurate information the = sensor temperature must be held within a critical narrow range. 2. To do this properly, the WBO2 manufacturer either programs into the = automobile's CPU or provides a separate "control" chip that uses a PID = (Proportional, Integral, derivative) the control algorithm necessary to = hold the required critical temperature range. 3. Failure to hold this temp range renders the sensor output of = questionable accuracy and will lead to degradation/failure of the = sensor. 4. The PID temp control is much more complex than the algorithm = required to read the output voltage=20 So while I could add the WBO2 sensor - without the separate algorithm = (or control chip), the validity of the data is uncertain and likely = misleading. So no WBO2 option any time soon. Yet this project is much more straightforward than a knock sensor. Most = automobile engine manufactures can afford to do the research and they = can spread the cost over millions of engines sold. As you might = imagine, the results of their R&D is considered proprietary information = and seldom available to the public. Ed From: Tracy=20 Sent: Monday, August 29, 2011 9:24 AM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: How to tune with ADI? What Ed said. There is a knock sensor input on the EC3 but after = finding the same facts as Ed mentioned, it takes a lot more R&D to = implement it so that's why it's currently unused. Tracy Sent from my iPad On Aug 29, 2011, at 8:33 AM, "Ed Anderson" = wrote: The problem with Knock sensors is that they need to be able to = identify the "knock" sound characteristic of the engine you have it on. = The circuit is basically simple - the challenge is design the = parameters of a signal filter that permits the circuit to properly = identify (filter) the "Knock" charactertistic of your particular engine. = =20 So I would suggest that a knock system for a rotary might have = different characteristics than for a piston engine. So what might work = fine for a piston engine might not work so well on a rotary. But, on = the other hand it might work fine. Ed From: stevei@carey.asn.au=20 Sent: Monday, August 29, 2011 3:45 AM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: How to tune with ADI? Hi Dave=20 If you are chasing a circuit for knock sensing try: http://siliconchip.com.au/cms/A_108910/article.html Cheers Steve Izett Perth WA On 29/08/2011, at 12:24 PM, David Leonard wrote: Ok, So I have the new ADI system installed and working.... I = think? Some of you smart racing guys probably have experience with ADI. Most of the instructions that come with tuning it are directed = toward car guys that have computers and knock sensors. All they do is = turn the system on and the computer allows more advance because I is not = sensing any knock. The only real advise I have so for for me is that I = should be running just less than the amount of ADI that it takes to bog = down the engine. My system is a fixed flow so I don't have much choice = but it seems to be about right. If I use straight water (which I did = for initial testing), the engine bogs after about 10-15 seconds of = ruining the ADI system. But when I uses a 50/50 mix of water and = denatured alcohol (too hard to find methanol around here, but close = enough) the engine does not bog. So assuming my amount of ADI injected is about right, now I am = supposed to be able to lean to better power and advance the timing a = little. But how much? For the last testing flight I was using EGT for = lack of a better guide. When the ADI comes on, my EGT drops by about 30 = deg C, and there is a hint of roughness to the engine. I can then lean = a little and the roughness clears up. For my test flight I leaned until = my EFT came back up to where I normally limit it (890 deg C). But if I = then add 5 more inches of MAP, there is still a hint of roughness even = at 890 deg and I get the sense that it wants to be leaned a little more. = But I am afraid to do that... We are talking 45" MAP and 7300 RPM here = (185 KTS indicated (Vne) and climbing at 500 fpm). =20 So here are my questions: Is EGT a useful tool here, and does leaning to get the EGT back to = 890 make any sense? Since Methanol will do such a good job at preventing detonation, is = it safe to lean further toward best power (peak EGT)? (note, that will = be hard on the turbo... I need to remember to bring the spare one to = Reno) How much advance do you think i can add? I was previously ruining 5 = deg ahead of Tracy's recommended initial set up. Can't give a number = because the EC2 retards the timing with higher MAP's. How much, I have = not heard. I can easily add one deg at a time using Ed's EFI monitor. = But without a knock sensor am really in the blind. Thoughts? =20 --=20 David Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.net http://RotaryRoster.net -------------------------------------------------------------------------= ----- The contents of this email are confidential and intended only for the = named recipients of this e-mail. If you have received this e-mail in = error, you are hereby notified that any use, reproduction, disclosure or = distribution or the information contained in this e-mail is prohibited. = Please notify the sender immediately and then delete/destroy the e-mail = and any printed copies. All liability for viruses is excluded to the = fullest extent of the law. ------=_NextPart_000_0009_01CC6637.72B15340 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
A thought occurred to me.  If anyone has a = spectrum=20 analyzer (Steve??) and could obtain an Rotary Knock sensor - that = perhaps=20 determining the frequency response of the knock sensor MIGHT indicate = the=20 frequency band pass required.  Although it is likely to be too = broad to be=20 much help if ( as likely) they do the filtering through a bandpass = filter within=20 the engine CPU.
 
Ed

Sent: Monday, August 29, 2011 9:54 AM
Subject: [FlyRotary] Not so Simple was Knock sensor was tune = with=20 ADI: [FlyRotary] Re: How to tune with ADI?

As Tracy also indicated - in may cases, =  what=20 initially appears simple - frequently turns out not to be the case, =  when you dive into the details. 
 
Another seemingly simple project I thought = about, was to=20 add a wide band O2 (WBO2) sensor option for the EFISM.  = This in order=20 to provide more accurate info on the air/fuel ratio (although one could = argue=20 just how useful that might be for our applications). 
 
While providing an algorithm for the different = voltage=20 input curve of the WBO2 sensor (it is much more linear than the = narrow band=20 O2 sensor curve) is straightforward, when you dive deeper you discover=20 that:
 
1.  For the wide band O2 sensor to provide = accurate=20 information the sensor temperature must be held within a = critical narrow=20  range.
2.  To do this properly, the WBO2  = manufacturer=20 either programs into the automobile's  CPU or provides a separate = "control"=20 chip that uses a PID (Proportional, Integral, derivative) the control = algorithm=20 necessary to hold the required critical temperature range.
3.  Failure to hold this temp range renders = the=20 sensor output of questionable accuracy and will lead to = degradation/failure of=20 the sensor.
4.  The PID temp control is much more = complex than=20 the algorithm required to read the output voltage
 
So while I could add the WBO2 sensor - without = the=20 separate algorithm (or control chip), the validity of the data is = uncertain and=20 likely misleading.  So no WBO2 option any time soon.
 
Yet this project is much more straightforward = than a knock=20 sensor.  Most automobile engine manufactures can afford to do the = research=20 and they can spread the cost over millions of engines sold.  As you = might=20 imagine, the results of their R&D is considered proprietary = information and=20 seldom available to the public.
 
Ed
 
 

From: Tracy
Sent: Monday, August 29, 2011 9:24 AM
Subject: [FlyRotary] Re: How to tune with = ADI?

What Ed said.   There is a knock sensor input on the EC3 but = after=20 finding the same facts as Ed mentioned, it takes a lot more R&D to = implement=20 it so that's why it's currently unused.

Tracy

Sent from my iPad

On Aug 29, 2011, at 8:33 AM, "Ed Anderson" <eanderson@carolina.rr.com&g= t;=20 wrote:

The problem with Knock sensors is that they = need to be=20 able to identify  the "knock" sound characteristic of the engine = you have=20 it on.  The circuit is basically simple - the challenge is design = the=20 parameters of a signal filter that permits the circuit to properly = identify=20 (filter) the "Knock" charactertistic of your particular=20 engine. 
 
So I would suggest that a knock system for a = rotary=20 might have different characteristics than for a piston engine.  = So what=20 might work fine for a piston engine might not work so well on a = rotary. =20 But, on the other hand it might work fine.
 
Ed

Sent: Monday, August 29, 2011 3:45 AM
Subject: [FlyRotary] Re: How to tune with = ADI?

Hi Dave=20
If you are chasing a circuit for knock sensing try:

Cheers

Steve Izett
Perth WA
On 29/08/2011, at 12:24 PM, David Leonard wrote:
Ok,  So I have the new ADI system installed and = working.... =20 I think?
 
Some of you smart racing guys probably have experience with = ADI.
 
Most of the instructions that come with tuning it are directed = toward=20 car guys that have computers and knock sensors.  All they do is = turn=20 the system on and the computer allows more advance because I is not = sensing=20 any knock.  The only real advise I have so for for me is that I = should=20 be running just less than the amount of ADI that it takes to bog = down the=20 engine.  My system is a fixed flow so I don't have much choice = but it=20 seems to be about right.  If I use straight water (which I did = for=20 initial testing), the engine bogs after about 10-15 seconds of = ruining the=20 ADI system.  But when I uses a 50/50 mix of water and denatured = alcohol=20 (too hard to find methanol around here, but close enough) the engine = does=20 not bog.
 
So assuming my amount of ADI injected is about right, now I am = supposed=20 to be able to lean to better power and advance the timing a = little. =20 But how much?  For the last testing flight I was using EGT for = lack of=20 a better guide.  When the ADI comes on, my EGT drops by about = 30 deg C,=20 and there is a hint of roughness to the engine.  I can then = lean a=20 little and the roughness clears up.  For my test flight I = leaned until=20 my EFT came back up to where I normally limit it (890 deg C).  = But if I=20 then add 5 more inches of MAP, there is still a hint of roughness = even at=20 890 deg and I get the sense that it wants to be leaned a little = more. But I=20 am afraid to do that...  We are talking 45" MAP and 7300 RPM = here (185=20 KTS indicated (Vne) and climbing at 500 fpm). 
 
So here are my questions:
Is EGT a useful tool here, and does leaning to get the EGT back = to 890=20 make any sense?
Since Methanol will do such a good job at preventing = detonation, is it=20 safe to lean further toward best power (peak EGT)? (note, that will = be hard=20 on the turbo...  I need to remember to bring the spare one = to=20 Reno)
How much advance do you think i can add?  I was=20 previously ruining 5 deg ahead of Tracy's recommended initial = set=20 up.  Can't give a number because the EC2 retards the = timing with=20 higher MAP's.  How much, I have not heard.  I can easily = add one=20 deg at a time using Ed's EFI monitor.  But without a knock = sensor am=20 really in the blind.
 
Thoughts? 

--
David = Leonard

Turbo=20 Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net


The contents of this email = are confidential=20 and intended only for the named recipients of this e-mail. If you have = received this e-mail in error, you are hereby notified that any use,=20 reproduction, disclosure or distribution or the information contained = in this=20 e-mail is prohibited. Please notify the sender immediately and then=20 delete/destroy the e-mail and any printed copies. All liability for = viruses is=20 excluded to the fullest extent of the=20 law.
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