X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.121] verified) by logan.com (CommuniGate Pro SMTP 5.1.12) with ESMTP id 2340059 for flyrotary@lancaironline.net; Wed, 19 Sep 2007 13:15:43 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.121; envelope-from=eanderson@carolina.rr.com Received: from edward2 ([24.74.103.61]) by cdptpa-omta02.mail.rr.com with SMTP id <20070919171505.MRBC3965.cdptpa-omta02.mail.rr.com@edward2> for ; Wed, 19 Sep 2007 17:15:05 +0000 Message-ID: <000701c7fae0$ba4152d0$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Strange Ignition? Date: Wed, 19 Sep 2007 13:15:50 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0004_01C7FABF.32F1BF70" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 This is a multi-part message in MIME format. ------=_NextPart_000_0004_01C7FABF.32F1BF70 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Al, let me clarify my comment about the split timing. In the automobile = the trailing plug is electronically set to "trail" the leading by approx = 15 deg (as best I recall). I believe the physical location of the = trailing plug offsets the timing something like 5 deg, so even if the = sparks happen simultaneously from the EC2 , the trailing plug is still = further behind in the rotation combustion timing progression. Now, = whether this would have the effect you are seeing, I certainly don't = know.=20 I would certainly check and make certain they didn't send you home with = the incorrect pulley (just kidding). =20 Perhaps while the engine appears to be running OK at the lower rpm, it = might be that the effect is not as adverse because leading plug is still = within an acceptable sparking region - but as rpm gets higher and more = advanced is needed/signaled it advances out of the optimum zone and the = trailing plug moves into it. In otherwords, correcting the problem = might give you even more power at lower rpm. Yes, I probably did disable the trailing when I was experimenting trying = to less the SAG effect, but once I found that disabling the leading = apparently help raise the temps and burned off some of the carbon = temporarily eliminating the SAG effect, I just didn't try eliminating = the trailing spark any more. I personally would double check (without the timing mark) your static = timing mark using one of the many techniques to establish Top Dead = Center by viewing the apex seal, etc, and verify that the mark you have = on the cover and/or the pulley is indeed TDC. Good Luck Ed ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Wednesday, September 19, 2007 12:00 PM Subject: [FlyRotary] Re: Strange Ignition?=20 Al, I did not catch what your ignition timing you have set when = encountering this. IF you set the ignition timing with little/no = advance/retard then you are around 25 deg BTDC. ED; The static timing is set according to Tracy's spec; 35o BTDC with = 2-point trigger aligned. From there it's up to the EC2 built-in timing = curve. IF you ignition was advancing to the point that the leading plug spark = point was exceeding the optimum for those combustion conditions (rpm, = manifold pressure, ignition timing, etc), then the trailing spark which = lags might start to become the optimum spark in relation to the optimum = spark point. If so then I would expect the higher the rpm the more = influence the trailing spark might have. Thank you for that. We had experienced this on the dyno; but my = recollection has been backwards. I have been thinking that it indicated = the timing was late. You forced me to go back and check my dyno report; = which says: 2.) Engine ran better on trailing plugs than on the leading plugs. = After much double checking, head scratching, and some further testing we = concluded that the only explanation could be that the timing was = actually very much early. And the only way that could be true was if = the timing marks and the pointer did not relate to the position of the = rotors. By viewing the position of the apex seal through the two spark plug = holes, measuring angles, etc. we made a new TDC mark on the pulley, and = a new 20 Degree BTDC mark. Then reset the static timing on the crank = angle sensor, and fired up. Ran well, and disabling leading had a = bigger effect than disabling trailing, as one would expect. To verify = timing we put a pressure transducer into the trailing plug hole, ran an = oscilloscope trace triggered by an inductor on the leading plug wire. = One step back on the EC2 timing adjustment gave us the trace we wanted. = (Fortunately, operators knew what the right trace looks like based on = their prior rotary development work). The original timing mark was about = 15 degrees too early - apparently the result of using a 12A front cover = (with pointer) on a 20B; using the stock 20B pulley. So; now I believe the timing is too early at the higher power. But = the question remains - why? And is it curious that it seems right at low = power, and too early at high power? In any case, I will retard the = spark and see what that does.=20 2. Unlikely as well, but I assume there is no change the coils = (you have six?) could be sequenced/hooked up improperly. I don't know = what the effect would be if the leading coils were sparking the trailing = plugs with the EC2. I know the timing split between the leading and = trailing is much less than in the automobile ignition timing - but I do = not believe it is zero. So the engine might well run, but might have = some unexpected things happening. Worth another check. My understanding from Tracy is that leading and = trailing fire at the same time - unless it has changed since we talked = about it.=20 3. I have disabled my leading ignition while flying (it helps if = you encounter a bad case of SAG) and I notice no difference in power = although the EGT on both will increase about 150F from 1600-1750F. Do = you notice any change in your EGT when you do this? That's interesting - I would expect that you would/should. Have you = tried disabling the trailing?=20 Al ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Tuesday, September 18, 2007 3:40 PM Subject: [FlyRotary] Re: One for the guys that don't give up The reason Tracy gave for the ECU not working was because of that = set-up, as his Vacuum pick -up is at the Plenum - something to do with = fluctuations within the tube, whereby the plenum was static or less = successful to wild fluctuations. George ( down under) I have accumulator and orifice which smooths the MAP nicely. Dave said: Besides a slight difference in the mixture necessary = between the 2 computers, both locations seem to work well. Dave: Mine works well also - except for the anomaly noted. I don't = know if you mean that yours specifically doesn't exhibit that = phenomenon? Al, was 35=B0 BTDC Tracys suggested timing? The 35o BTDC is the static setting specified in Tracy's manual; line = up the 2-point trigger wheel with the reluctors at that point. Quite frankly, I haven't tried the coil disable feature at high rpm = yet. So, I don't have an answer to your question. Heck, I can't even = get my auto-tune to work.=20 Mark; well, whenever you get that far, give it a shot and see what = you get. Good luck with the auto-tune. Does anyone else experience these symptoms? That's the question. Thanks, guys, Al OK; Mark; (or anybody). Since we both have 20Bs, and both use the = EC2 controller, maybe you have a clue for this one. I've brought this up = here before, but no solution. I have all the latest updates on the EC2, and I have double = checked the static timing set at 35o BTDC. From that point on the EC2 = is handling the timing curve with rpm and MAP. At lower power levels, disabling the leading ignition clearly has = a larger effect than disabling the trailing - as one would expect. At = somewhere around 18" MAP, (don't know right now what rpm that is, maybe = close to 4000) the effect is about equal when disabling either set. At = higher power levels, there is a larger effect of disabling the trailing = than the leading. That troubles me. I think the leading should always = have a greater effect. It makes me wonder about the timing; or if = something else is wrong.=20 I have in the past tried varying the timing 2 or 3 steps while at = power, but couldn't discern a change in rpm greater than the normal = variation in the readout. Tracy sent me the XL spreadsheet with the = timing curve data, but I haven't yet figured a safe way of checking it = with that prop spinning close by. Does your installation exhibit the same behavior? Is there some = explanation for this? What test should I perform? One thing that occurs to me is that Tracy measures MAP out before = the runners. I measure MAP at the manifold, downstream from intake = plenum and three short runners and the 3-barrel TWM throttle body. At = WOT my MAP is not atmospheric pressure - it is maybe 2-3" HG less. I = can't quite see how that is an issue; but maybe someone else with a TWM = TB setup with the MAP port downstream would know. Other than that I'm very pleased with the new mixture correction = table setup for the 20B. Much less tuning and seamless transistion = between tables and through the stage point. Probably the pulse clamping = and injector isolation diodes are part of that. -------------------------------------------------------------------------= - No virus found in this incoming message. Checked by AVG Free Edition.=20 Version: 7.5.487 / Virus Database: 269.13.22/1013 - Release Date: = 17/09/2007 1:29 PM ------=_NextPart_000_0004_01C7FABF.32F1BF70 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Al, let me clarify my comment about the split=20 timing.  In the automobile the trailing plug is electronically set = to=20 "trail" the leading by approx 15 deg (as best I recall).  I believe = the=20 physical location of the trailing plug offsets the timing =  something like 5=20 deg, so even if the sparks happen simultaneously from the EC2 , the = trailing=20 plug is still further behind in the rotation combustion timing=20 progression.  Now, whether this would have the effect you are = seeing, I=20 certainly don't know. 
 
I would certainly check and make certain they = didn't send=20 you home with the incorrect pulley (just kidding). 
 
Perhaps while the engine appears to be running = OK at the=20 lower rpm, it might be that the effect is not as adverse because leading = plug is=20 still within an acceptable sparking region - but as rpm gets higher and = more=20 advanced is needed/signaled it advances out of the optimum zone and the = trailing=20 plug moves into it.  In otherwords, correcting the problem might = give you=20 even more power at lower rpm.
 
Yes, I probably did disable the trailing when I = was=20 experimenting trying to less the SAG effect, but once I found that = disabling the=20 leading apparently help raise the temps and burned off some of the = carbon=20 temporarily eliminating the SAG effect, I just didn't try eliminating = the=20 trailing spark any more.
 
I personally would double check (without the = timing mark)=20 your static timing mark using one of the many techniques to establish = Top Dead=20 Center by viewing the apex seal, etc, and verify that the mark you = have =20  on the cover and/or the pulley is indeed TDC.
 
Good Luck
 
Ed
----- Original Message -----
From:=20 Al = Gietzen=20
Sent: Wednesday, September 19, = 2007 12:00=20 PM
Subject: [FlyRotary] Re: = Strange=20 Ignition?

 

Al, I did not catch what = your=20 ignition timing you have set when encountering this.  IF you set = the=20 ignition timing with little/no advance/retard then you are around 25 = deg=20 BTDC.

ED;

 

The = static timing=20 is set according to Tracy=92s = spec;=20 35o BTDC with 2-point trigger aligned.  From there = it=92s up to=20 the EC2 built-in timing curve.

 

IF you ignition was = advancing to=20 the point that the leading plug spark point was exceeding the optimum = for=20 those combustion conditions (rpm, manifold=20 pressure, ignition timing, etc), then the = trailing spark which=20 lags might start to become the optimum spark in relation to the = optimum=20 spark point.  If so then I would expect the higher the rpm the = more=20 influence the trailing spark might have.

 

Thank you = for=20 that.  We had experienced this on the dyno; but my recollection = has been=20 backwards.  I have been thinking that it indicated the timing was = late.=20 You forced me to go back and check my dyno report; which=20 says:

2.) = Engine ran=20 better on trailing plugs than on the leading plugs.  After much = double=20 checking, head scratching, and some further testing we concluded that = the only=20 explanation could be that the timing was actually very much = early.  And=20 the only way that could be true was if the timing marks and the = pointer did=20 not relate to the position of the = rotors.

By = viewing the=20 position of the apex seal through the two spark plug holes, measuring = angles,=20 etc. we made a new TDC mark on the pulley, and a new 20 Degree BTDC=20 mark.  Then reset the static timing on the crank angle sensor, = and fired=20 up.  Ran well, and disabling leading had a bigger effect than = disabling=20 trailing, as one would expect.  To verify timing we put a = pressure=20 transducer into the trailing plug hole, ran an oscilloscope trace = triggered by=20 an inductor on the leading plug wire. One step back on the EC2 timing=20 adjustment gave us the trace we wanted. (Fortunately, operators knew = what the=20 right trace looks like based on their prior rotary development work). = The=20 original timing mark was about 15 degrees too early =96 apparently the = result of=20 using a 12A front cover (with pointer) on a 20B; using the stock 20B=20 pulley.

So; now I = believe=20 the timing is too early at the higher power.  But the question = remains =96=20 why? And is it curious that it seems right at low power, and too early = at high=20 power?  In any case, I will retard the spark and see what that=20 does. 

2.    =20 Unlikely as well, but I assume there is = no change=20 the coils (you have six?) could be sequenced/hooked up = improperly.  I=20 don't know what the effect would be if the leading coils were sparking = the=20 trailing plugs with the EC2.  I know the timing split between the = leading=20 and trailing is much less than in the automobile ignition timing - but = I do=20 not believe it is zero.  So the engine might well run, but might = have=20 some unexpected things happening.

Worth = another=20 check.  My understanding from Tracy is that = leading=20 and trailing fire at the same time = =96 unless it=20 has changed since we talked about it.

 

3.    =20 I have disabled my leading ignition while = flying=20 (it helps if you encounter a bad case of SAG) and I notice no = difference=20 in power although the EGT on both will increase about 150F from=20 1600-1750F.  Do you notice any change in your EGT when you do=20 this?

 

That=92s = interesting =96=20 I would expect that you would/should.  Have you tried disabling = the=20 trailing?

 

Al

----- Original Message = -----=20

From: Al = Gietzen=20

To: Rotary motors in = aircraft=20

Sent:=20 Tuesday, September 18, = 2007 3:40=20 PM

Subject:=20 [FlyRotary] Re: One for the guys that don't give = up

 

The reason = Tracy gave=20 for the ECU not working was because of that set-up, as = his Vacuum pick=20 -up is at the Plenum - something to do with fluctuations within = the=20 tube, whereby the plenum was static or less successful to wild=20 fluctuations.

George ( down=20 under)

 

I=20 have accumulator and orifice which smooths the MAP = nicely.

 

Dave said:  Besides a = slight=20 difference in the mixture necessary between the 2 computers, both = locations=20 seem to work well.

 

Dave:  Mine=20 works well also - except for the anomaly noted.  I don=92t know = if you=20 mean that yours specifically doesn=92t exhibit that=20 phenomenon?

 

Al,=20 was 35=B0 BTDC Tracys suggested timing?

 

The=20 35o BTDC is the static setting specified in = Tracy=92s = manual; line=20 up the 2-point trigger wheel with the reluctors at that=20 point.

 

Quite frankly, I haven't = tried the=20 coil disable feature at high rpm yet.  So, I don't have an = answer=20 to your question.  Heck, I can't even get my auto-tune to=20 work. 

 

Mark; = well,=20 whenever you get that far, give it a shot and see what you get. Good = luck=20 with the auto-tune.

 

  Does anyone else = experience=20 these symptoms?   That=92s the=20 question.

 

Thanks, = guys,

 

Al

 

 

 

 

 

OK; = Mark; (or=20 anybody).  Since we both have 20Bs, and both use the EC2 = controller,=20 maybe you have a clue for this one. I=92ve brought this up here = before, but=20 no solution.

I=20 have all the latest updates on the EC2, and I have double checked = the=20 static timing set at 35o BTDC.  From that point on = the EC2=20 is handling the timing curve with rpm and MAP.

At=20 lower power levels, disabling the leading ignition clearly has a = larger=20 effect than disabling the trailing =96 as one would expect. =  At=20 somewhere around 18=94 MAP, (don=92t know right now what rpm that = is, maybe=20 close to 4000) the effect is about equal when disabling either = set.=20  At higher power levels, there is a larger effect of = disabling the=20 trailing than the leading.  That troubles me.  I think = the=20 leading should always have a greater effect.  It makes me = wonder=20 about the timing; or if something else is wrong. =

I=20 have in the past tried varying the timing 2 or 3 steps while at = power, but=20 couldn=92t discern a change in rpm greater than the normal = variation in the=20 readout.  Tracy sent = me the XL=20 spreadsheet with the timing curve data, but I haven=92t yet = figured a safe=20 way of checking it with that prop spinning close = by.

Does = your=20 installation exhibit the same behavior?  Is there some = explanation=20 for this?  What test should I perform?

One = thing that=20 occurs to me is that Tracy = measures MAP=20 out before the runners.  I measure MAP at the manifold, = downstream=20 from intake plenum and three short runners and the 3-barrel TWM = throttle=20 body.  At WOT my MAP is not atmospheric pressure =96 it is = maybe 2-3=94=20 HG less.  I can=92t quite see how that is an issue; but maybe = someone=20 else with a TWM TB setup with the MAP port downstream would=20 know.

 

Other = than that=20 I=92m very pleased with the new mixture correction table setup for = the=20 20B.  Much less tuning and seamless transistion between = tables and=20 through the stage point.  Probably the pulse clamping and = injector=20 isolation diodes are part of that.

No virus found in this = incoming=20 message.
Checked by AVG Free Edition.
Version: 7.5.487 / = Virus=20 Database: 269.13.22/1013 - Release Date: 17/09/2007 = 1:29=20 PM

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