Return-Path: Received: from fed1rmmtao07.cox.net ([68.230.241.32] verified) by logan.com (CommuniGate Pro SMTP 4.2) with ESMTP id 380079 for flyrotary@lancaironline.net; Thu, 26 Aug 2004 21:14:39 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.32; envelope-from=ALVentures@cox.net Received: from BigAl ([68.107.116.221]) by fed1rmmtao07.cox.net (InterMail vM.6.01.03.02.01 201-2131-111-104-103-20040709) with ESMTP id <20040827011407.GBTZ24357.fed1rmmtao07.cox.net@BigAl> for ; Thu, 26 Aug 2004 21:14:07 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: Engine run Date: Thu, 26 Aug 2004 18:14:13 -0700 Message-ID: <000001c48bd3$2a509160$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C48B98.7DF1B960" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C48B98.7DF1B960 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I guess I have now done what I=92d consider the first serious runs of = the engine on the plane, and I have so many question marks in my head, = it=92s hard to know what to address next. The biggest issue is; I cannot get smooth running up to about 2200 rpm; which is as far as I went. At about 2000 I adjusted mixture from too = lean to too rich, and nowhere does it smooth out completely =96 some = roughness, mild surging. At lower rpm, 1000 =96 1500 it is quite rough and = unsteady, which is disconcerting in itself, but worrisome when it goes through = periods of torsional vibration with the reduction gear backlash, which is noisy = and shakes the plane. Of course it brings back the recent discussions of you other guys with = the 550 injectors in the primary. I kind of glossed over that because I recalled smooth running on the dyno. In hindsight now, I think the = operator figured out early-on that to keep it smooth he needed to keep some load = on =96 just turn the load knob a little and it was fine. And on the dyno when = it wasn=92t running smooth, no big deal =96 no redrive to backlash, and the = engine is bolted down in the next room. You could just hear that it wasn=92t = running smooth. Still, I suspect something is different now; and perhaps you=92ll = indulge my dumping, and pass on a clue or two. At 2000 I=92m seeing a 13.1 MAP reading. Seems low to me. Is it? That = puts it below the stage point, yet when I turned off the primary injectors, = it continued to run; just rougher. Same effect turning off the = secondaries. Hotest EGT was at about 1100, lowest about 980. Bigger spread than I = ever saw on the dyno runs, but the data we took there was always under higher load. Fuel pressure reads 50 psi, TWM tells me it came to me preset at 43.5. = When the coolant temp read 125 when the pipes and rad tanks were just about = too hot to touch, which I guessed to be more like 140. I=92m suspicious of = just about every readout. Later when the WT read 140, the CHT TC that measure temps in and out of the rads were reading about 85. I believed backup gauges were unnecessary. Oh yeah; the mixture bar reads just about full scale all the time, even = when the engine is about to die from being too lean. I have a different = heated Bosch sensor, which I assumed would have the same 0-1volt range. Maybe = not. Is the sensor output voltage low when lean or rich? With the engine off = and sensor heated I measured .052 volts. I tried to get a reading with the engine running, but all I got was about .025 and I can=92t be certain I = had contact with the lead =96 and with the prop spinning so close by I = didn=92t spend too much time trying. One other major concern. With hot oil (150) at the filter block where = the feed goes to the redrive, the =BC=94 Al line to the redrive was hardly = above ambient temp a minute or two after shutdown; suggesting little or no = flow was going there. Oil pressure was in the 90=92s. I=92m not aware that = there is an orifice in there. This has me a bit baffled. Oil pressure, coolant pressure, Oil temp seem fine. Maybe I should go to a movie. Al (not ecstatic) =20 ------=_NextPart_000_0001_01C48B98.7DF1B960 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message

I guess I have now done what I’d consider the first serious runs of = the engine on the plane, and I have so many question marks in my head, = it’s hard to know what to address next.

The biggest = issue is; I cannot get smooth running up to about 2200 rpm; which is as far as I = went. =A0At about 2000 I adjusted mixture from too lean to too rich, and nowhere = does it smooth out completely – some roughness, mild surging.=A0 At lower = rpm, 1000 – 1500 it is quite rough and unsteady, which is disconcerting in = itself, but worrisome when it goes through periods of torsional vibration with = the reduction gear backlash, which is noisy and shakes the = plane.

Of course it = brings back the recent discussions of you other guys with the 550 injectors in = the primary.=A0 I kind of glossed over that because I recalled smooth = running on the dyno.=A0 In hindsight now, I think the operator figured out early-on that to keep = it smooth he needed to keep some load on – just turn the load knob a = little and it was fine. =A0And on the dyno when it wasn’t running smooth, = no big deal – no redrive to backlash, and the engine is bolted down in = the next room.=A0 You could just hear that it wasn’t running = smooth.

Still, I = suspect something is different now; and perhaps you’ll indulge my dumping, = and pass on a clue or two.

At 2000 = I’m seeing a 13.1 MAP reading.=A0 Seems low to me.=A0 Is it? That puts it = below the stage point, yet when I turned off the primary injectors, it continued = to run; just rougher. =A0Same effect turning off the secondaries.=A0 Hotest EGT = was at about 1100, lowest about 980. =A0Bigger spread than I ever saw on the = dyno runs, but the data we took there was always under higher = load.

Fuel pressure = reads 50 psi, TWM tells me it came to me preset at 43.5.=A0 When the coolant temp read = 125 when the pipes and rad tanks were just about too hot to touch, which I = guessed to be more like 140. =A0I’m suspicious of just about every readout. = Later when the WT read 140, the CHT TC that measure temps in and out of the rads = were reading about 85.=A0 I believed backup gauges were = unnecessary.

Oh yeah; the = mixture bar reads just about full scale all the time, even when the engine is = about to die from being too lean.=A0 I have a different heated Bosch sensor, = which I assumed would have the same 0-1volt range. =A0Maybe not.=A0 Is the = sensor output voltage low when lean or rich? =A0With the engine off and sensor heated I = measured .052 volts.=A0 I tried to get a reading with the engine running, but all I = got was about .025 and I can’t be certain I had contact with the lead = – and with the prop spinning so close by I didn’t spend too much time = trying.

One other = major concern.=A0 With hot oil (150) at the filter block where the feed goes to the = redrive, the =BC” Al line to the redrive was hardly above ambient temp a minute or two = after shutdown; suggesting little or no flow was going there.=A0 Oil pressure = was in the 90’s.=A0 I’m not aware that there is an orifice in = there. =A0This has me a bit baffled.

Oil pressure, = coolant pressure, Oil temp seem fine.

Maybe I should = go to a movie.

Al (not = ecstatic)

 

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