X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-fx0-f52.google.com ([209.85.161.52] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with ESMTPS id 5107641 for flyrotary@lancaironline.net; Mon, 29 Aug 2011 18:26:12 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.161.52; envelope-from=wdleonard@gmail.com Received: by fxd18 with SMTP id 18so4622118fxd.25 for ; Mon, 29 Aug 2011 15:25:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=qjf5m4Oi5MtrQthPARvjBPrRAb+SYLPQO3dnm0ckSuQ=; b=T/kObNm2EecOjZL2GRXQTuHZMOpHoYa0VoKtjcA6VRIqplA9GsRoWCfZ5c32JX+LjF a7r3q2z1mrUrWZ51oCYVEOfTd9l+LgMiGXHsJyQb4q6Pfp3aclRJmkSuYdO81Q91+NA/ 9gCRHhZY8VJvvfVQEVpGpBqIzhbmYF3EZW1i8= MIME-Version: 1.0 Received: by 10.223.4.133 with SMTP id 5mr7955950far.81.1314656734217; Mon, 29 Aug 2011 15:25:34 -0700 (PDT) Received: by 10.223.74.202 with HTTP; Mon, 29 Aug 2011 15:25:34 -0700 (PDT) In-Reply-To: References: Date: Mon, 29 Aug 2011 15:25:34 -0700 Message-ID: Subject: Re: [FlyRotary] Re: Freq analysis of Knock sensor? From: David Leonard To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=000e0ce03ca4a506e604abac5f42 --000e0ce03ca4a506e604abac5f42 Content-Type: text/plain; charset=ISO-8859-1 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. -- 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 > *Sent:* Monday, August 29, 2011 2:51 PM > *To:* Rotary motors in aircraft > *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. > > -- > 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 >> *Sent:* Monday, August 29, 2011 9:54 AM >> *To:* Rotary motors in aircraft >> *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. >> >> 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). >> >> 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 >> >> 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 >> *Sent:* Monday, August 29, 2011 9:24 AM >> *To:* Rotary motors in aircraft >> *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. >> >> 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 >> *Sent:* Monday, August 29, 2011 3:45 AM >> *To:* Rotary motors in aircraft >> *Subject:* [FlyRotary] Re: How to tune with ADI? >> >> Hi Dave >> 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). >> >> 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? >> >> -- >> 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. >> >> > > > --000e0ce03ca4a506e604abac5f42 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable I sent an e-mail to the guy who makes this knock sensor:
http://www.viatrack.ca/

It is a small, inex= pensive unit.=A0 He said that the thing that determines the key frequency i= s the bore of the cylinder.=A0 He claims to have made several for rotary en= gines and they worked.=A0 He used the thickness of the rotor as a rough app= roximation of bore.

The problem I have is that the unit comes with a pot adjustment for sen= sitivity.=A0 So how do you know if your pot adjustment is too sensitive or = if you are getting real detonation?=A0 Guess I'll go ask him.

--=
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 <eanderson@carolina.rr.com> = wrote:
I was referring to the sensor itself, Dave=
=A0
I agree with your assessment - without the parame= ters with=20 which to design the signal filter - you don't stand much of a chance.= =A0 I=20 had thought that perhaps if the sensor itself had a narrow band response th= at=20 might give a clue as to the knock signal spectrum.=A0 But, again, agree its= =20 unlikely
=A0
Edd

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 comput= er=20 itself, or the sensor.=A0 I think that the sensors are all pretty much the= =20 same, just a form of microphone.=A0 It is not the sensor that is tuned to t= he=20 engine, but the filters in the computer.=A0 And if you had a computer, you= =20 wouldn't need to build another one unless you wanted to sell them.
<= br>--=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 <eanderson@carolina.rr.com>=20 wrote:
A thought occurred to me.=A0 If anyone has a sp= ectrum=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.=A0 Although it is likely to be too broad to= =20 be much help if ( as likely) they do the filtering through a bandpass fil= ter=20 within the engine CPU.
=A0
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=A0- in may cases, =A0wh= at=20 initially appears simple -=A0frequently turns out not to be the case,=20 =A0when you dive into the details.=A0
=A0
Another seemingly simple project I thought abou= t, was to=20 add a wide band O2 (WBO2) sensor option for the EFISM.=A0 This=A0in=20 order to provide more accurate info on the air/fuel ratio (although one c= ould=20 argue just how useful that might be for our applications).=A0
=A0
While providing an algorithm for the different = voltage=20 input curve of the WBO2 sensor=A0(it is much more linear than the narrow= =20 band O2 sensor curve) is straightforward, when you dive deeper you discov= er=20 that:
=A0
1.=A0 For the wide band O2 sensor to provide ac= curate=20 information the sensor temperature must be held within a critical=A0narro= w=20 =A0range.
2.=A0 To do this properly, the WBO2=A0=20 manufacturer either programs into the automobile's =A0CPU 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.=A0 Failure to hold this temp range renders t= he=20 sensor output of questionable accuracy and will lead to degradation/failu= re of=20 the sensor.
4.=A0 The PID temp control is much more complex= than=20 the algorithm required to read the output voltage
=A0
So while I could add the WBO2 sensor - without = the=20 separate algorithm (or control chip), the validity of the data is uncerta= in=20 and likely misleading.=A0 So no WBO2 option any time soon.
=A0
Yet this project is much more straightforward t= han a=20 knock sensor.=A0 Most automobile engine manufactures can afford to do the= =20 research and they can spread the cost over millions of engines sold.=A0 A= s=20 you might imagine, the results of their R&D is considered proprietary= =20 information and seldom available to the public.
=A0
Ed
=A0
=A0

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

What Ed said. =A0 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 n= eed to be=20 able to identify=A0 the "knock" sound characteristic of the e= ngine you=20 have it on.=A0 The circuit is basically simple - the challenge is desig= n=20 the parameters of a signal filter that permits the circuit to properly= =20 identify (filter)=A0the "Knock" charactertistic of=A0your par= ticular=20 engine.=A0
=A0
So I would suggest that a knock system for a = rotary=20 might have different characteristics than for a piston engine.=A0 So wh= at=20 might work fine for a piston engine might not work so well on a=20 rotary.=A0 But, on the other hand it might work fine.
=A0
Ed

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

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,=A0 So I have the new ADI system installed and=20 working....=A0 I think?
=A0
Some of you smart racing guys probably have experience with=20 ADI.
=A0
Most of the instructions that come with tuning it are directed t= oward=20 car guys that have computers and knock sensors.=A0 All they do is tur= n=20 the system on and the computer allows more advance because I is not= =20 sensing any knock.=A0 The only real advise I have so for for me is th= at=20 I should be running just less than the amount of ADI that it takes to= bog=20 down the engine.=A0 My system is a fixed flow so I don't have muc= h=20 choice but it seems to be about right.=A0 If I use straight water=20 (which I did for initial testing), the engine bogs after about 10-15= =20 seconds of ruining the ADI system.=A0 But when I uses a 50/50 mix of= =20 water and denatured alcohol (too hard to find methanol around here, b= ut=20 close enough) the engine does not bog.
=A0
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.=A0 But how much?=A0 For the last testing flight I was using= =20 EGT for lack of a better guide.=A0 When the ADI comes on, my EGT drop= s=20 by about 30 deg C, and there is a hint of roughness to the engine.=A0= I=20 can then lean a little and the roughness clears up.=A0 For my test=20 flight I leaned until my EFT came back up to where I normally limit i= t=20 (890 deg C).=A0 But if I then add 5 more inches of MAP, there is stil= l=20 a hint of roughness even at 890 deg and I get the sense that it wants= to=20 be leaned a little more. But I am afraid to do that...=A0 We are=20 talking 45" MAP and 7300 RPM here (185 KTS indicated (Vne)=A0and= =20 climbing at 500 fpm).=A0
=A0
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 wil= l be=20 hard on the turbo...=A0 I need to remember to=A0bring the spare one= =20 to Reno)
How much advance do you think i can add?=A0 I=A0was=20 previously=A0ruining 5 deg ahead of Tracy's recommended initial s= et=20 up.=A0 Can't give a number=A0because the EC2 retards the timing w= ith=20 higher MAP's.=A0 How much, I have not heard.=A0 I can easily add = one=20 deg at a time using Ed's EFI monitor.=A0 But without a knock sens= or am=20 really in the blind.
=A0
Thoughts?=A0

--
David Leonard

T= urbo=20 Rotary RV-6 N4VY
= http://N4VY.RotaryRoster.net
h= ttp://RotaryRoster.net


The contents of this ema= il 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 an= y=20 use, reproduction, disclosure or distribution or the information contai= ned=20 in this e-mail is prohibited. Please notify the sender immediately and = then=20 delete/destroy the e-mail and any printed copies. All liability for vir= uses=20 is excluded to the fullest extent of the=20 law.







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