Return-Path: <13brv3@bellsouth.net> Received: from imf18aec.mail.bellsouth.net ([205.152.59.66] verified) by logan.com (CommuniGate Pro SMTP 4.1.1) with ESMTP id 2545487 for flyrotary@lancaironline.net; Sun, 24 Aug 2003 22:52:07 -0400 Received: from rad ([68.212.14.21]) by imf18aec.mail.bellsouth.net (InterMail vM.5.01.05.27 201-253-122-126-127-20021220) with ESMTP id <20030825025206.YRQT13779.imf18aec.mail.bellsouth.net@rad> for ; Sun, 24 Aug 2003 22:52:06 -0400 From: "Russell Duffy" <13brv3@bellsouth.net> To: "Flyrotary List" Subject: Turbo flames, and spontaneous brake failures Date: Sun, 24 Aug 2003 21:52:06 -0500 Message-ID: <000001c36ab3$dee13fe0$0201a8c0@rad> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C36A89.F60B37E0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4510 Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C36A89.F60B37E0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Greetings, =20 =20 As before, I'm going to be lazy and just post my daily log. I'm sure = the turbo flame subject will make you read it :-) =20 Rusty =20 =20 =20 8-24-03 / 8 hours / 1385 total =20 Finished up the top cowl tidbits, and tuned the engine. The A = controller was perfect, with Tracy's default settings. I did set the staging point = at 18" MAP (12" vacuum, 14" vacuum indicated on my defective gauge), but it = ran OK before I changed this too. So much for the good news. =20 =20 The B controller was waaaaaaay rich across the board. I couldn't get = the mixture lean enough, even with the mixture knob all the way CCW, so used mode 3 to reduce the flow rate several steps to bring the mixture down = to the point where I could center the mixture knob. I also set the staging point at 18" MAP on the B controller, but had to do lots of fiddling = with the mixture to get the low power and staging area to behave. It's odd, = the mixture indication on the AF gauge needs to be leaner with the B = controller, than it does with the A. In other words, on the A controller, two = yellow bars rich of center is what seems to run best at low power, but on the B controller, it's one yellow bar rich of center. If you try to get two, = it just won't run right, and can be improved by turning the mixture knob = CCW. Very strange. Don't understand this, but it works. =20 My theory, until proven wrong, is that the intake air temp at the = throttle body is pretty darned hot. Since it was 100 degrees on the ramp, and = I'm running a turbo with no intercooler, I can imagine this to be true. The = A controller compensates for this by reducing the fuel flow to match the = very hot air. The B controller doesn't have a temp sensor, so it assumes = that the air isn't so hot, and gives me far more fuel than I need. Yep, that EM-2 would sure tell me how hot the air temp is :-) In the mean time, = I'm going to take this as another reason to NOT boost the engine too much at = low altitude, since the air is so hot already. =20 =20 Now, as for injector mismatch problems- it seems that the only = operational problem appears when you turn off the primary injectors (wimpy = over-rated MSD's), and try to run at low power. At higher powers, the engine seems = to function OK, but I have to turn the mixture almost fully CCW to make the engine happy at low power. I don't see this as a no-go problem, but = would like to match these up better at some point. I'll be sending all my = unused injectors (2-MSD's, and 4- Mazda 550's) out to someone this week to find = out what they really flow. =20 =20 While testing the engine, doing everything I could think of to throw it = off, I was going from idle to full throttle, then back to idle. A friend on = the ground was shocked to see a nice flame appear at the turbo exhaust when = I closed the throttle suddenly. I hadn't noticed this before, but I'm not surprised, or alarmed by it, because RX-7's do it too if you take off = the catalytic converters. What was more entertaining/disturbing was when I accidentally left the cold start switch engaged while trying to start a = hot engine. The engine was too rich to fire, but the turbo ignited the = fuel, and kept a continuous orange flame about a foot long flowing out of the exhaust pipe. I can live without seeing that again :-) =20 For the record, both the tiny tach, and the new Equus 8068 worked = perfectly. Static rpm at 30" MAP was 4900, and at 36" MAP was 5400. This is just a = bit below the 5000 at sea level that I was looking for, but I think I'll = leave it hear for now. I'm pretty sure I have enough power to fly :-) =20 Finally, I took the plane for a spin around the taxiway, and tried to = clean the rest of the crud from the brake discs. About half way around the airport, I noticed that the left brake pedal would sink if I held it. Knowing what this meant, I took it back to the hanger and found that the flare fitting on the aluminum hose at the brake caliper just decided to start leaking. After all the times I've tried to over-stress these = lines by standing on the brakes, it just decided that now was the time to leak. = By the time I got back to the hanger, it was just dripping from gravity pressure. Just amazing. Of course now I have to pull the top skin = again to get to the reservoir when I fix the connection. Rats. =20 ------=_NextPart_000_0001_01C36A89.F60B37E0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message

Greetings,  =

 

As before, I'm going to be lazy and just post = my daily=20 log.  I'm sure the turbo flame subject will make you read it=20 :-)

 

Rusty

 

 

 

8-24-03  = /  8 hours  / =20 1385 total

 

Finished up the top cowl tidbits, and tuned the = engine.  The A controller = was=20 perfect, with Tracy’s default = settings.  I did set the staging point at = 18” MAP=20 (12” vacuum, 14” vacuum indicated on my defective gauge), = but it ran OK before I=20 changed this too.  So much = for the=20 good news.  =

 

The B controller was waaaaaaay rich across the board.  I couldn’t get the = mixture lean enough,=20 even with the mixture knob all the way CCW, so used mode 3 to reduce the = flow=20 rate several steps to bring the mixture down to the point where I could = center=20 the mixture knob.  I also = set the=20 staging point at 18” MAP on the B controller, but had to do lots = of fiddling=20 with the mixture to get the low power and staging area to behave.  It’s odd, the mixture = indication on the=20 AF gauge needs to be leaner with the B controller, than it does with the = A.  In other words, on the A = controller, two=20 yellow bars rich of center is what seems to run best at low power, but = on the B=20 controller, it’s one yellow bar rich of center. If you try to get = two, it just=20 won’t run right, and can be improved by turning the mixture knob = CCW.  Very strange.  Don’t understand this, = but it=20 works.

 

My theory, until proven wrong, is that the = intake air=20 temp at the throttle body is pretty darned hot.  Since it was 100 degrees on = the ramp,=20 and I’m running a turbo with no intercooler, I can imagine this to = be true.  The A controller compensates = for this by=20 reducing the fuel flow to match the very hot air.  The B controller doesn’t = have a temp=20 sensor, so it assumes that the air isn’t so hot, and gives me far = more fuel than=20 I need.  Yep, that EM-2 = would sure=20 tell me how hot the air temp is :-) In the mean time, I’m going to = take this as=20 another reason to NOT boost the engine too much at low altitude, since = the air=20 is so hot already. =20

 

Now, as for injector mismatch problems- it = seems that the=20 only operational problem appears when you turn off the primary injectors = (wimpy=20 over-rated MSD’s), and try to run at low power.  At higher powers, the engine = seems to=20 function OK, but I have to turn the mixture almost fully CCW to make the = engine=20 happy at low power.  I = don’t see=20 this as a no-go problem, but would like to match these up better at some = point.  I’ll be = sending all my=20 unused injectors (2-MSD’s, and 4- Mazda 550’s) out to = someone this week to find=20 out what they really flow. =20

 

While testing the engine, doing everything I could think of to = throw it=20 off, I was going from idle to full throttle, then back to idle.  A friend on the ground was = shocked to=20 see a nice flame appear at the turbo exhaust when I closed the throttle=20 suddenly.  I hadn’t = noticed this=20 before, but I’m not surprised, or alarmed by it, because = RX-7’s do it too if you=20 take off the catalytic converters. =20 What was more entertaining/disturbing was when I accidentally = left the=20 cold start switch engaged while trying to start a hot engine.  The engine was too rich to = fire, but the=20 turbo ignited the fuel, and kept a continuous orange flame about a foot = long=20 flowing out of the exhaust pipe.  = I=20 can live without seeing that again :-)

 

For the record, both the tiny tach, and the new Equus 8068 = worked=20 perfectly.  Static rpm at = 30” MAP=20 was 4900, and at 36” MAP was 5400. =20 This is just a bit below the 5000 at sea level that I was looking = for,=20 but I think I’ll leave it hear for now. =20 I’m pretty sure I have enough power to fly :-)

 

Finally, I took the plane for a spin around the = taxiway,=20 and tried to clean the rest of the crud from the brake discs.  About half way around the = airport, I=20 noticed that the left brake pedal would sink if I held it.  Knowing what this meant, I = took it back=20 to the hanger and found that the flare fitting on the aluminum hose at = the brake=20 caliper just decided to start leaking. =20 After all the times I’ve tried to over-stress these lines = by standing on=20 the brakes, it just decided that now was the time to leak.  By the time I got back to the = hanger, it=20 was just dripping from gravity pressure. =20 Just amazing.  Of = course now=20 I have to pull the top skin again to get to the reservoir when I fix the = connection.  Rats.        

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