X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail.qnsi.net ([66.219.56.248] verified) by logan.com (CommuniGate Pro SMTP 5.2.5) with ESMTP id 3025444 for flyrotary@lancaironline.net; Mon, 14 Jul 2008 14:19:55 -0400 Received-SPF: none receiver=logan.com; client-ip=66.219.56.248; envelope-from=bhughes@qnsi.net Content-class: urn:content-classes:message Return-Receipt-To: "Bobby J. Hughes" MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C8E5E6.D2039F59" Subject: RE: [FlyRotary] pre-mix; great trip Disposition-Notification-To: "Bobby J. Hughes" X-MimeOLE: Produced By Microsoft Exchange V6.5 Date: Mon, 14 Jul 2008 14:21:30 -0500 Message-ID: <74120FDE88CAFE4DBDA8814BCE20A3F302D152@qnsi-mail.qnsi.net> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [FlyRotary] pre-mix; great trip Thread-Index: AcjlACHYfn7h0NzFSD2WLHwx4mYqOAA5iTpg References: From: "Bobby J. Hughes" To: "Rotary motors in aircraft" This is a multi-part message in MIME format. ------_=_NextPart_001_01C8E5E6.D2039F59 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Al, =20 What size inlet are you using on your in-cowl radiator? My notes show = it's 11.5 x 16 x 2.75.=20 =20 Thanks,=20 =20 Bobby ________________________________ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On = Behalf Of Al Gietzen Sent: Sunday, July 13, 2008 9:48 AM To: Rotary motors in aircraft Subject: [FlyRotary] pre-mix; great trip Just returned from about 2500 nm trip. Engine ran great, including = flying over the Rockies west of Denver where I was briefly at about = 14,000 ft with density altitude of 16,500, and still had some throttle = to go. Generally cruising at 165 KTAS, 9.2 - 9.5 gph, about 5600 rpm. = Not bad for a 4-place airplane. =20 OK, now for some technical stuff. You may recall I converted my 20B = over from pan oil injection to using premix. =20 The main issue is the amount of 2-cycle oil that is ending up in the oil = pan. When mixing 1 oz/gal I found the pan oil level had gone up by = about 1 =BD quarts (from 6 =BD to 8) in about 15 hours of flying; and my = nice clear-amber 15-50 synthetic had become the dark blue-black color of = the SuperTech 2-cycle oil. Doing the math suggests that about 1/3 of the = pre-mix oil is ending up in the pan. That seems way out of line, and = although a suspect it is not harmful to the engine, I don't think it the = best lube for the re-drive. I changed the oil and reduced the amount of = pre-mix to =BE oz per gallon. I'll be surprised if there isn't still = some 2-cycle oil going into the pan. =20 So. . ; suggestions? Use different brand 2-cycle? Further reduce = pre-mix amount? =20 I'm wondering if the fact that my cruise coolant temp is now running = around 150F would result in more of the pre-mix to condense out than if = it was running at maybe 180F. =20 Another thing I notice is a small amount of fuel is coming out of the = fuel vent. The only explanation I can come up with is foaming/bubbles = forming in the return line after the pressure regulator. This goes into = the 3-gallon sump tank and up the =BC" vent line. This may have been = occurring previously, and the fuel evaporated as it went back along the = surface; but now the blue 2-cycle oil is left behind to be quite visible = at the back of the cowl; but I suspect the pre-mix is exacerbating the = foaming.=20 =20 I notice the plugs have less carbon than before, and the inside of the = exhaust exit is now very light grey. =20 Al ------_=_NextPart_001_01C8E5E6.D2039F59 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Al,

What size inlet are you using on your in-cowl = radiator? My notes show it's 11.5 x 16 x 2.75. =

Thanks,

Bobby

From: Rotary motors in aircraft=20 [mailto:flyrotary@lancaironline.net] On Behalf Of Al=20 Gietzen
Sent: Sunday, July 13, 2008 9:48 AM
To: = Rotary=20 motors in aircraft
Subject: [FlyRotary] pre-mix; great=20 trip

Just = returned from=20 about 2500 nm trip. Engine ran great, including flying over the=20 Rockies west of=20 Denver where I = was briefly=20 at about 14,000 ft with density altitude of 16,500, and still had some = throttle=20 to go. Generally cruising at 165 KTAS, 9.2 =96 9.5 gph, about 5600 rpm. = Not bad=20 for a 4-place airplane.

OK, now for = some=20 technical stuff. You may = recall I=20 converted my 20B over from pan oil injection to using = premix.

The main = issue is the=20 amount of 2-cycle oil that is ending up in the oil pan. When = mixing 1=20 oz/gal I found the pan oil level had gone up by about 1 =BD quarts = (from 6 =BD=20 to 8) in about 15 hours of flying; and my nice clear-amber 15-50 = synthetic had=20 become the dark blue-black color of the SuperTech 2-cycle oil. Doing the = math=20 suggests that about 1/3 of the pre-mix oil is ending up in the = pan. That=20 seems way out of line, and although a suspect it is not harmful to the = engine, I=20 don=92t think it the best lube for the re-drive. I changed the oil = and=20 reduced the amount of pre-mix to =BE oz per gallon. I=92ll be = surprised if=20 there isn=92t still some 2-cycle oil going into the = pan.

So. . ;=20 suggestions? Use different brand 2-cycle? Further reduce = pre-mix=20 amount?

I=92m = wondering if the=20 fact that my cruise coolant temp is now running around 150F would result = in more=20 of the pre-mix to condense out than if it was running at maybe=20 180F.

Another = thing I=20 notice is a small amount of fuel is coming out of the fuel vent. = The only=20 explanation I can come up with is foaming/bubbles forming in the return = line=20 after the pressure regulator. This goes into the 3-gallon sump = tank and up=20 the =BC=94 vent line. This may have been occurring previously, and = the fuel=20 evaporated as it went back along the surface; but now the blue 2-cycle = oil is=20 left behind to be quite visible at the back of the cowl; but I suspect = the=20 pre-mix is exacerbating the foaming.

I notice = the plugs=20 have less carbon than before, and the inside of the exhaust exit is now = very=20 light grey.

Al

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