X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao105.cox.net ([68.230.241.41] verified) by logan.com (CommuniGate Pro SMTP 5.1.10) with ESMTP id 2172299 for flyrotary@lancaironline.net; Wed, 11 Jul 2007 23:23:02 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.41; envelope-from=alventures@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao105.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20070712032225.NMZS1399.fed1rmmtao105.cox.net@fed1rmimpo01.cox.net> for ; Wed, 11 Jul 2007 23:22:25 -0400 Received: from BigAl ([72.192.132.90]) by fed1rmimpo01.cox.net with bizsmtp id NTNQ1X00D1xAn3c0000000; Wed, 11 Jul 2007 23:22:24 -0400 From: "Al Gietzen" To: "Rotary motors in aircraft" Subject: EC2 changes Date: Wed, 11 Jul 2007 20:23:45 -0800 Message-ID: <000001c7c43c$6faf9bd0$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C7C3F9.618ECCD0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C7C3F9.618ECCD0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Further to my last posting on the subject; we did the following changes = to my 20B EC2 =20 1. reduced values of the added caps for noise filtering on the ignitions circuits by a factor of ten. 2. replaced the MAP pressure sensor on Controller "A" 3. added what is being referred to as the 'clamping diodes' or 'snubbers' on the injector circuits. =20 Changing the capacitors had no noticeable effect on what I believed was = a timing issue. I still find that at low power disabling leading coils = has definitely more effect than disabling trailing; whereas at high power, = say about 19" MAP and above, disabling the leading has small effect and disabling trialing has larger effect. I have concluded that the timing = is not late with both on; since I found that now retarding the timing a 2-3 steps (4-5 degrees) at power increased the rpm a bit. I think the larger caps did result in a small retarding of the spark. =20 Does anyone else with a 3-rotor, and using the LS1 coils, note the same behavior when disabling leading/trailing ignition? Tracy mentioned that = on his 20B using the renesis coils, disabling either set results in the = engine stopping, so there may be something amiss in the circuitry. =20 I thought that the strange leaning of mixture with altitude when running = on controller A was solved by replacing the pressure sensor - until I got = over 5000'. Then over the next 200 ft increase the mixture monitor bar on = the EM2 went slowly off the bottom of the scale, and it took turning the = mixture knob to about 3:00 position to return it to a mid-scale reading. = Switching to controller B gave me a momentary scare - the engine quit, well = completely lost power for the fraction of a second that it took to switch back to = A. More on this below. =20 Adding the snubbers on the injector circuits resulted in quite a = different profile on the mixture table settings. It also resulted in smoother = running at low rpm, and seemingly easier tuning to get smooth transition from = 'low' to 'high' table, and across the stage point (or maybe I'm just getting better re-tuning). =20 =20 One thing I had discovered when re-tuning was that, apparently due to powering up the unit on the bench to check the MAP sensor, resulted in = the injector pulse setting (mode 3) to get set to a much lower value, and = the stage point to someplace out of range. The engine would only run with = the cold start switch on. Once I got those things straightened out, things proceeded smoothly. When I had all well on controller A, I did the copy = A to B. Prior to flying, I had not checked running on B. (OK, it's on my = check list, I just bypassed it.) After the episode in the air I figured out = that B was acting like A did before the retuning. I tried multiple times again = to copy A to B; but it did not take. I had to manually retune B to get = things running right. Don't know what, but the copy A to B is not working. =20 Didn't mean to run on here - am I boring anyone yet:-)? =20 Expect to fly tomorrow for some air pressure measurements on the oil = cooler. =20 Al =20 =20 ------=_NextPart_000_0001_01C7C3F9.618ECCD0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Further to my last posting on the subject; we did = the following changes to my 20B EC2

 

  1. reduced values of the added caps for noise = filtering on the ignitions circuits by a factor of ten.
  2. replaced the MAP pressure sensor on Controller = “A”
  3. added what is being referred to as the = ‘clamping diodes’ or ‘snubbers’ on the injector = circuits.

 

Changing the capacitors had no noticeable effect on = what I believed was a timing issue.  I still find that at low power = disabling leading coils has definitely more effect than disabling trailing; whereas at = high power, say about 19” MAP and above, disabling the leading has small = effect and disabling trialing has larger effect.  I have concluded that the = timing is not late with both on; since I found that now retarding the timing a 2-3 = steps (4-5 degrees) at power increased the rpm a bit. I think the larger caps did = result in a small retarding of the spark.

 

Does anyone else with a 3-rotor, and using the LS1 = coils, note the same behavior when disabling leading/trailing ignition?  Tracy = mentioned that on his 20B using the renesis coils, disabling either set results in the = engine stopping, so there may be something amiss in the = circuitry.

 

I thought that the strange leaning of mixture with altitude when running on controller A was solved by replacing the = pressure sensor – until I got over 5000’.  Then over the next = 200 ft increase the mixture monitor bar on the EM2 went slowly off the bottom of the = scale, and it took turning the mixture knob to about 3:00 position to return it to = a mid-scale reading.  Switching to controller B gave me a momentary scare = – the engine quit, well completely lost power for the fraction of a second that it = took to switch back to A. More on this below.

 

Adding the snubbers on the injector circuits = resulted in quite a different profile on the mixture table settings.  It also = resulted in smoother running at low rpm, and seemingly easier tuning to get = smooth transition from ‘low’ to ‘high’ table, and = across the stage point (or maybe I’m just getting better re-tuning).  =

 

One thing I had discovered when re-tuning was that, apparently due to powering up the unit on the bench to check the MAP = sensor, resulted in the injector pulse setting (mode 3) to get set to a much = lower value, and the stage point to someplace out of range.  The engine = would only run with the cold start switch on.  Once I got those things straightened out, things proceeded smoothly.  When I had all well = on controller A, I did the copy A to B. Prior to flying, I had not checked = running on B. (OK, it’s on my check list, I just bypassed it.) After the = episode in the air I figured out that B was acting like A did before the = retuning. I tried multiple times again to copy A to B; but it did not take.  I = had to manually retune B to get things running right.  Don’t know = what, but the copy A to B is not working.

 

Didn’t mean to run on here – am I = boring anyone yetJ?

 

Expect to fly tomorrow for some air pressure = measurements on the oil cooler.

 

Al

 

 

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