X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.120] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with ESMTP id 5107677 for flyrotary@lancaironline.net; Mon, 29 Aug 2011 19:44:59 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.120; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=1.1 cv=clOQl2Kon9ihL0vqe5S6shCOWnQ8eDPHG/StQ1omz74= c=1 sm=0 a=syR5QHIlSpUA:10 a=SC71y0a/4S6V9vjVxUojGA==:17 a=QuJOnMU6AAAA:8 a=N8B9JuSIAAAA:8 a=ayC55rCoAAAA:8 a=OBoQRNBVAAAA:8 a=hem2GDRAKn3_4I5jRRIA:9 a=vawiy1TtdZWC-q3mfAQA:7 a=wPNLvfGTeEIA:10 a=pYEayob8caUA:10 a=BapRk1qX-GmlllbS:21 a=UjpyonqNkKvDU51h:21 a=pGLkceISAAAA:8 a=Ia-xEzejAAAA:8 a=_HBAOssS5BCT6eoZjlUA:9 a=pn5hk9XIjtqmdsON0tgA:7 a=tXsnliwV7b4A:10 a=MSl-tDqOz04A:10 a=EzXvWhQp4_cA:10 a=SC71y0a/4S6V9vjVxUojGA==:117 X-Cloudmark-Score: 0 X-Originating-IP: 174.110.175.135 Received: from [174.110.175.135] ([174.110.175.135:49268] helo=EdPC) by cdptpa-oedge01.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id EC/DE-15370-6542C5E4; Mon, 29 Aug 2011 23:44:22 +0000 Message-ID: <5DA6B8D69FF84F5EB216D1DC66023714@EdPC> From: "Ed Anderson" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Resonate Cavity volume - neat: [FlyRotary] Re: Freq analysis of Knock sensor? Date: Mon, 29 Aug 2011 19:42:14 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002E_01CC6683.C0C003A0" 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_002E_01CC6683.C0C003A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Looks like the price is right. Yes, I can see that the largest volume = might act like an organ horn (resonate cavity) - presumably any hollow = volume has a primary resonate frequency - and with an explosion going = off in that volume, the frequency response would undoubtedly be related = to the volume. Nice bit of thinking there. Ed From: David Leonard=20 Sent: Monday, August 29, 2011 6:25 PM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: Freq analysis of Knock sensor? I sent an e-mail to the guy who makes this knock sensor: http://www.viatrack.ca/ It is a small, inexpensive unit. He said that the thing that determines = the key frequency is the bore of the cylinder. He claims to have made = several for rotary engines and they worked. He used the thickness of = the rotor as a rough approximation of bore. The problem I have is that the unit comes with a pot adjustment for = sensitivity. So how do you know if your pot adjustment is too sensitive = or if you are getting real detonation? Guess I'll go ask him. --=20 David Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.net http://RotaryRoster.net On Mon, Aug 29, 2011 at 3:14 PM, Ed Anderson = wrote: I was referring to the sensor itself, Dave I agree with your assessment - without the parameters with which to = design the signal filter - you don't stand much of a chance. I had = thought that perhaps if the sensor itself had a narrow band response = that might give a clue as to the knock signal spectrum. But, again, = agree its unlikely Edd From: David Leonard=20 Sent: Monday, August 29, 2011 2:51 PM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: Freq analysis of Knock sensor? By Rotary Knock sensor, I am not sure if you mean the computer itself, = or the sensor. I think that the sensors are all pretty much the same, = just a form of microphone. It is not the sensor that is tuned to the = engine, but the filters in the computer. And if you had a computer, you = wouldn't need to build another one unless you wanted to sell them. --=20 David Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.net http://RotaryRoster.net On Mon, Aug 29, 2011 at 7:36 AM, Ed Anderson = wrote: 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_002E_01CC6683.C0C003A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Looks like the price is right.  Yes, I can = see that=20 the largest volume might act like an organ horn (resonate cavity) - = presumably=20 any hollow volume has a primary resonate frequency - and with an = explosion going=20 off in that volume, the frequency response would undoubtedly be related = to the=20 volume.  Nice bit of thinking there.
 
Ed

Sent: Monday, August 29, 2011 6:25 PM
Subject: [FlyRotary] Re: Freq analysis of Knock=20 sensor?

I sent an e-mail to the guy who makes this knock = sensor:
http://www.viatrack.ca/

It = is a small,=20 inexpensive unit.  He said that the thing that determines the key = frequency=20 is the bore of the cylinder.  He claims to have made several for = rotary=20 engines and they worked.  He used the thickness of the rotor as a = rough=20 approximation of bore.

The problem I have is that the unit comes = with a=20 pot adjustment for sensitivity.  So how do you know if your pot = adjustment=20 is too sensitive or if you are getting real detonation?  Guess I'll = go ask=20 him.

--
David Leonard

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

On Mon, Aug 29, 2011 at 3:14 PM, Ed Anderson = <eanderson@carolina.rr.com&g= t;=20 wrote:
I was referring to the sensor itself, = Dave
 
I agree with your assessment - without the = parameters=20 with which to design the signal filter - you don't stand much of a=20 chance.  I had thought that perhaps if the sensor itself had a = narrow=20 band response that might give a clue as to the knock signal = spectrum. =20 But, again, agree its unlikely
 
Edd

From: David Leonard =
Sent: Monday, August 29, 2011 2:51 PM
Subject: [FlyRotary] Re: Freq analysis of Knock=20 sensor?

By Rotary Knock sensor, I am not sure if you mean the = computer=20 itself, or the sensor.  I think that the sensors are all pretty = much the=20 same, just a form of microphone.  It is not the sensor that is = tuned to=20 the engine, but the filters in the computer.  And if you had a = computer,=20 you wouldn't need to build another one unless you wanted to sell=20 them.

--
David Leonard

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

On Mon, Aug 29, 2011 at 7:36 AM, Ed Anderson = <eanderson@carolina.rr.com> wrote:
A thought occurred to me.  If anyone = has a=20 spectrum analyzer (Steve??) and could obtain an Rotary Knock sensor = - that=20 perhaps determining the frequency response of the knock sensor MIGHT = indicate the frequency band pass required.  Although it is = likely to be=20 too broad to be much help if ( as likely) they do the filtering = through a=20 bandpass filter within the engine CPU.
 
Ed

Sent: Monday, August 29, 2011 9:54 AM
Subject: [FlyRotary] Not so Simple was Knock sensor was = tune=20 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=20 the case,  when you dive into the details. 
 
Another seemingly simple project I thought = about, was=20 to add a wide band O2 (WBO2) sensor option for the EFISM.  = This in=20 order to provide more accurate info on the air/fuel ratio (although = one=20 could argue just how useful that might be for our = applications). =20
 
While providing an algorithm for the = different voltage=20 input curve of the WBO2 sensor (it is much more linear than the = narrow=20 band O2 sensor curve) is straightforward, when you dive deeper you = discover=20 that:
 
1.  For the wide band O2 sensor to = provide=20 accurate information the sensor temperature must be held within a=20 critical narrow  range.
2.  To do this properly, the WBO2  = manufacturer either programs into the automobile's  CPU or = provides a=20 separate "control" chip that uses a PID (Proportional, Integral, = derivative)=20 the control algorithm necessary to hold the required critical = temperature=20 range.
3.  Failure to hold this temp range = renders the=20 sensor output of questionable accuracy and will lead to = degradation/failure=20 of the sensor.
4.  The PID temp control is much more = complex=20 than 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=20 and likely misleading.  So no WBO2 option any time = soon.
 
Yet this project is much more = straightforward than a=20 knock sensor.  Most automobile engine manufactures can afford = to do the=20 research and they can spread the cost over millions of engines = sold. =20 As you might imagine, the results of their R&D is considered = proprietary=20 information and 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=20 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" <eanderson@carolina.rr.com> = wrote:

The problem with Knock sensors is that = they need to=20 be able to identify  the "knock" sound characteristic of the = engine=20 you have it on.  The circuit is basically simple - the = challenge is=20 design the parameters of a signal filter that permits the circuit = to=20 properly identify (filter) the "Knock" charactertistic = of your=20 particular engine. 
 
So I would suggest that a knock system for = a rotary=20 might have different characteristics than for a piston = engine.  So=20 what might work fine for a piston engine might not work so well on = a=20 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
Subject: [FlyRotary] Re: How to tune with=20 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=20 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=20 toward car guys that have computers and knock sensors.  All = they do=20 is turn the system on and the computer allows more advance = because I is=20 not sensing any knock.  The only real advise I have so for = for me=20 is that I should be running just less than the amount of ADI = that it=20 takes to bog down the engine.  My system is a fixed flow so = I don't=20 have much choice but it seems to be about right.  If I use = straight=20 water (which I did for initial testing), the engine bogs after = about=20 10-15 seconds of ruining the ADI system.  But when I uses a = 50/50=20 mix of water and denatured alcohol (too hard to find methanol = around=20 here, but close enough) the engine does not bog.
 
So assuming my amount of ADI injected is about right, now I = am=20 supposed to be able to lean to better power and advance the = timing a=20 little.  But how much?  For the last testing flight I = was=20 using EGT for lack of a better guide.  When the ADI comes = on, my=20 EGT drops by about 30 deg C, and there is a hint of roughness to = the=20 engine.  I can then lean a little and the roughness clears=20 up.  For my test flight I leaned until my EFT came back up = to where=20 I normally limit it (890 deg C).  But if I then add 5 more = inches=20 of MAP, there is still a hint of roughness even at 890 deg and I = get the=20 sense that it wants to be leaned a little more. But I am afraid = to do=20 that...  We are talking 45" MAP and 7300 RPM here (185 KTS=20 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=20 890 make any sense?
Since Methanol will do such a good job at preventing = detonation, is=20 it safe to lean further toward best power (peak EGT)? (note, = that will=20 be hard on the turbo...  I need to remember to bring = the spare=20 one to 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=20 with higher MAP's.  How much, I have not heard.  I can = easily=20 add one deg at a time using Ed's EFI monitor.  But without = a knock=20 sensor am really in the blind.
 
Thoughts? 

--
David = Leonard

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

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





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