X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from exchange.carey.wa.edu.au ([118.82.44.212] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with ESMTPS id 5108837 for flyrotary@lancaironline.net; Tue, 30 Aug 2011 19:30:21 -0400 Received-SPF: none receiver=logan.com; client-ip=118.82.44.212; envelope-from=stevei@carey.asn.au Received: from exchange.carey.local ([10.10.0.5]) by exchange.carey.local ([10.10.0.5]) with mapi; Wed, 31 Aug 2011 07:29:39 +0800 From: To: Date: Wed, 31 Aug 2011 07:29:42 +0800 Subject: Re: [FlyRotary] Re: Freq analysis of Knock sensor? Thread-Topic: [FlyRotary] Re: Freq analysis of Knock sensor? Thread-Index: AcxnbK+/1ivYHD6pTV650HyhZ+8kgQ== Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_B45A3A1AA0B84A5BA83511B7434709C0careyasnau_" MIME-Version: 1.0 --_000_B45A3A1AA0B84A5BA83511B7434709C0careyasnau_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hi Ed, mines a Super II not a III. So the gear is not so tall. Steve On 30/08/2011, at 10:13 PM, Ed Anderson wrote: That is one super aircraft - very sexy looking on that tall gear. But, one= heck of a lot of work. Let us all know when you have photos to share Ed From: stevei@carey.asn.au Sent: Tuesday, August 30, 2011 10:06 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Freq analysis of Knock sensor? Hi Ed I've had the engine running 18months ago but have it off the fuse so I can = rotate the thing for sanding. I'm building a Glasair Super II RG. Just finishing the Slotted Flaps at pre= sent. Hoping to put her together and retest engine by early next year. Sorry, not much help for now. Cheers Steve On 30/08/2011, at 7:50 PM, Ed Anderson wrote: Hi Steve, My understanding (Lynn will probably correct me here) is that under normal = loads, temps and fuel the probability of detonation or knock in a rotary en= gine is pretty small due to the characteristics of its combustion chamber. = Now under boost, there is no question you can get into the detonation rang= e, so it would seem to me that a knock sensor would be of biggest benefit t= o those with forced induction. I , for one, would be very interested in what you find when you listen in. = Wonder whether you might be able to make an audio recording of what the sy= stems puts out - there are some interesting analytical tools as pointed out= by Finn and several others that might be interesting to run the data throu= gh. I presume you have the engine running - just not up to full power, yet? Ed From: stevei@carey.asn.au Sent: Tuesday, August 30, 2011 4:38 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Freq analysis of Knock sensor? Hi Ed My Renesis came with the knock sensor, but as you say the bandwidth of the = sensor is probably to wide. Having the sensor I built up a kit knock sensor amp and filters. But as we = recognise the knock of a rotor may sound vastly different from a piston. I plan to listen in when I get to full power ground runs. Problem being I don't want to punish my engine to hear what it sounds like = when its complaining! Cheers Steve Izett On 29/08/2011, at 10:36 PM, 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 frequenc= y response of the knock sensor MIGHT indicate the frequency band pass requi= red. 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: [Fly= Rotary] Re: How to tune with ADI? As Tracy also indicated - in may cases, what initially appears simple - fr= equently 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 accurat= e 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 W= BO2 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 au= tomobile's CPU or provides a separate "control" chip that uses a PID (Prop= ortional, 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 questionab= le accuracy and will lead to degradation/failure of the sensor. 4. The PID temp control is much more complex than the algorithm required t= o read the output voltage So while I could add the WBO2 sensor - without the separate algorithm (or c= ontrol 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 au= tomobile engine manufactures can afford to do the research and they can spr= ead the cost over millions of engines sold. As you might imagine, the resu= lts 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 th= e "knock" sound characteristic of the engine you have it on. The circuit i= s basically simple - the challenge is design the parameters of a signal fil= ter that permits the circuit to properly identify (filter) the "Knock" char= actertistic of your particular engine. So I would suggest that a knock system for a rotary might have different ch= aracteristics than for a piston engine. So what might work fine for a pist= on engine might not work so well on a rotary. But, on the other hand it mi= ght 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 g= uys 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 jus= t less than the amount of ADI that it takes to bog down the engine. My sys= tem is a fixed flow so I don't have much choice but it seems to be about ri= ght. 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 arou= nd 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 m= uch? For the last testing flight I was using EGT for lack of a better guid= e. When the ADI comes on, my EGT drops by about 30 deg C, and there is a h= int 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 ah= ead 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 kno= ck 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 th= e sender immediately and then delete/destroy the e-mail and any printed cop= ies. All liability for viruses is excluded to the fullest extent of the law= . --_000_B45A3A1AA0B84A5BA83511B7434709C0careyasnau_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hi Ed, mines a Super II no= t a III. So the gear is not so tall.
Steve
On 30/08/2011, = at 10:13 PM, Ed Anderson wrote:

That is one super aircraft - very sexy looking on= that=20 tall gear.  But, one heck of a lot of work.
 
Let us all know when you have photos to=20 share
 
Ed

Sent: Tuesday, August 30, 2011 10:06 AM
Subject: [FlyRotary] Re: Freq analysis of Knock=20 sensor?

Hi Ed=20
I've had the engine running 18months ago but have it off the fuse so I= can=20 rotate the thing for sanding. 
I'm building a Glasair Super II RG. Just finishing the Slotted Flaps a= t=20 present.
Hoping to put her together and retest engine by early next year.
Sorry, not much help for now.

Cheers

Steve

On 30/08/2011, at 7:50 PM, Ed Anderson wrote:

Hi Steve,
 
My understanding (Lynn will probably correct me= here) is=20 that under normal loads, temps and fuel the probability of detonation or = knock=20 in a rotary engine is pretty small due to the characteristics of its=20 combustion chamber.  Now under boost, there is no question you can g= et=20 into the detonation range, so it would seem to me that a knock sensor wou= ld be=20 of biggest benefit to those with forced induction. 
 
I , for one, would be very interested in what y= ou find=20 when you listen in.  Wonder whether you might be able to make an aud= io=20 recording of what the systems puts out - there are some interesting analy= tical=20 tools as pointed out by Finn and several others that might be interesting= to=20 run the data through.
 
I presume you have the engine running - just no= t up to=20 full power, yet?
 
Ed

Sent: Tuesday, August 30, 2011 4:38 AM
Subject: [FlyRotary] Re: Freq analysis of Knock=20 sensor?

Hi Ed=20

My Renesis came with the knock sensor, but as you say the bandwidth = of=20 the sensor is probably to wide.
Having the sensor I built up a kit knock sensor amp and filters. But= as=20 we recognise the knock of a rotor may sound vastly different from a=20 piston.
I plan to listen in when I get to full power ground runs.
Problem being I don't want to punish my engine to hear what it sound= s=20 like when its complaining!

Cheers

Steve Izett
On 29/08/2011, at 10:36 PM, Ed Anderson wrote:

A thought occurred to me.  If anyone has= a=20 spectrum analyzer (Steve??) and could obtain an Rotary Knock sensor - t= hat=20 perhaps determining the frequency response of the knock sensor MIGHT=20 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 tun= e=20 with ADI: [FlyRotary] Re: How to tune with ADI?

As Tracy also indicated - in may cases,= =20  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 ab= out, was=20 to add a wide band O2 (WBO2) sensor option for the EFISM.  This&nb= sp;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 differen= t voltage=20 input curve of the WBO2 sensor (it is much more linear than the na= rrow=20 band O2 sensor curve) is straightforward, when you dive deeper you disc= over=20 that:
 
1.  For the wide band O2 sensor to provi= de=20 accurate information the sensor temperature must be held within a=20 critical narrow  range.
2.  To do this properly, the WBO2 = =20 manufacturer either programs into the automobile's  CPU or provide= s a=20 separate "control" chip that uses a PID (Proportional, Integral, deriva= tive)=20 the control algorithm necessary to hold the required critical temperatu= re=20 range.
3.  Failure to hold this temp range rend= ers the=20 sensor output of questionable accuracy and will lead to degradation/fai= lure=20 of the sensor.
4.  The PID temp control is much more co= mplex=20 than the algorithm required to read the output voltage
 
So while I could add the WBO2 sensor - withou= t the=20 separate algorithm (or control chip), the validity of the data is uncer= tain=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 d= o the=20 research and they can spread the cost over millions of engines sold.&nb= sp;=20 As you might imagine, the results of their R&D is considered propri= etary=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?
<= /div>

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>=20 wrote:

The problem with Knock sensors is that they= need to=20 be able to identify  the "knock" sound characteristic of the eng= ine=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 y= our=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

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:

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=20 ADI.
 
Most of the instructions that come with tuning it are directed= =20 toward car guys that have computers and knock sensors.  All th= ey 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 i= t=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 str= aight=20 water (which I did for initial testing), the engine bogs after abou= t=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 aroun= d=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 th= e=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 inc= hes=20 of MAP, there is still a hint of roughness even at 890 deg and I ge= t 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 bac= k to=20 890 make any sense?
Since Methanol will do such a good job at preventing detonatio= n, is=20 it safe to lean further toward best power (peak EGT)? (note, that w= ill=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 timi= ng=20 with higher MAP's.  How much, I have not heard.  I can ea= sily=20 add one deg at a time using Ed's EFI monitor.  But without a k= nock=20 sensor am really in the blind.
 
Thoughts? 

--
David Leonard
=
Turbo=20 Rotary RV-6 N4VY
<= a href=3D"http://N4VY.RotaryRoster.net/">http://N4VY.RotaryRoster.nethttp://RotaryRoster.net


The contents of this e= mail are=20 confidential and intended only for the named recipients of this e-mai= l. 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 cont= ained=20 in this e-mail is prohibited. Please notify the sender immediately an= d=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.



= --_000_B45A3A1AA0B84A5BA83511B7434709C0careyasnau_--