X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 16 Oct 2013 13:05:22 -0400 Message-ID: X-Original-Return-Path: Received: from mail-pb0-f49.google.com ([209.85.160.49] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTPS id 6542993 for lml@lancaironline.net; Wed, 16 Oct 2013 11:52:53 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.160.49; envelope-from=keith.smith@gmail.com Received: by mail-pb0-f49.google.com with SMTP id xb12so984926pbc.8 for ; Wed, 16 Oct 2013 08:52:17 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.68.226.3 with SMTP id ro3mr3551838pbc.72.1381936963218; Wed, 16 Oct 2013 08:22:43 -0700 (PDT) Received: by 10.70.48.66 with HTTP; Wed, 16 Oct 2013 08:22:43 -0700 (PDT) In-Reply-To: References: X-Original-Date: Wed, 16 Oct 2013 11:22:43 -0400 X-Original-Message-ID: Subject: Re: [LML] Re: LOP ops on O-360 A1A From: Keith Smith X-Original-To: Lancair Mailing List Content-Type: multipart/alternative; boundary=047d7b2e0825cb750004e8dd4574 --047d7b2e0825cb750004e8dd4574 Content-Type: text/plain; charset=ISO-8859-1 Hi George, I have heard that, yes. However, that would involve killing the ram air which is something I'd like to avoid. I shall tinker with it, though, on the next flight. Keith On Tue, Oct 15, 2013 at 12:49 PM, George Braly wrote: > Try using some carb heat. It will smooth out that engine significantly > when LOP. > > The warmer induction air does a much more uniform job of distributing the > fuel as vapor with less liquid drop outs in the induction plumbing. > > > > -----Original Message----- > From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of > vtailjeff@aol.com > Sent: Tuesday, October 15, 2013 8:21 AM > To: lml@lancaironline.net > Subject: [LML] Re: LOP ops on O-360 A1A > > Have you checked your baffling? > > Sent from my iPad > > On Oct 15, 2013, at 7:53 AM, Keith Smith wrote: > > > Hey all, > > > > I'm waiting for winter to come around but it seems like my O-360 A1A has > been running warmer than usual, requiring me to power back very shortly > after takeoff to avoid an excursion north of 425 degree CHT's. > > > > In any case, I know that LOP ops are hard to come by with an O-360 due > to poor fuel distribution. Indeed, my #4 cylinder peaks well before the > others, making it tricky to get them LOP. > > > > I've been running in two modes...one is around 20 LOP to cool it down to > around 385 CHT while the others run just slightly rich of peak. I can do > this without much effort, and under a wide range of throttle positions, and > density altitudes. > > > > On a recent flight, though, I found #1 and #3 settling on temps that > were just too high to be happy with. I would go well ROP to get them > cooled, but burned a lot of fuel in the process and still had a warm 4th > cylinder due to the fact that it runs quite a bit leaner. This was all done > at 75% power or less, btw, density altitude was well above 11k (I was at > 11k and it was +10C) > > > > Eventually, I tried something somewhat dramatic. I was determined to get > ALL the cylinders LOP. I leaned relatively rapidly and ignored the > disconcerting knocking/shuddering associated with the uneven amounts of > power being produced between the 4th cylinder and all the rest. > > > > It all happened a bit quickly, but with cylinder 1-3 roughly 20-40 LOP > and #4 70-90 LOP, the CHTs dropped like a stone, seemingly in seconds, down > to 380-385 across the board for #1-3 with #4 now in the 350-360 range. With > careful fiddling of the mixture, and countless experiments with throttle > position, I got the vibration down to the point where it was barely > noticeable. Eventually it just felt smooth...but I can't tell if I got used > to it, or things just settled down, although I wouldn't think it was > possible. > > > > Final fuel flow was around 8.8-9.0 gph. > > > > Finally, living the LOP dream with my O-360 :) > > > > I tried repeating this later on, down low and wasn't able to repeat it > (ie, never got it smooth). > > > > So, it's elusive, but possibly doable under just the right > circumstances. Since I do long trips on a regular basis, I'm definitely > interested in making this work. > > > > Separately, I'll try to find out why it's running warmer in general. I > did have a mag replaced, the other rebuilt, and 4 new plugs installed in > the last year. > > > > Honestly, I'm going to try to save some clams and get this converted to > an IO-360 (didn't realize it was relatively inexpensive until my mechanic > suggested it), get balanced injectors and run LOP as SOP. The difference in > cooling really is staggering. I know I'm probably preaching to the choir, > but I thought that O-360 owners might find it eye opening. Get up high and > give it a try if you have a 4 point engine monitor. You'll know it's > working when your leaning results in EGT and CHT's coming down :) > > > > The trip, btw, was N07-KFTW-KSAV-N07, around 2600nm. > > > > Keith > > -- > For archives and unsub > http://mail.lancaironline.net:81/lists/lml/List.html > > -- > For archives and unsub > http://mail.lancaironline.net:81/lists/lml/List.html > --047d7b2e0825cb750004e8dd4574 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
Hi George,

I have heard that, yes. Howe= ver, that would involve killing the ram air which is something I'd like= to avoid. I shall tinker with it, though, on the next flight.
Keith


On Tue, Oct 15, 2013 at 12:49 PM, George Braly <gwbraly@= gami.com> wrote:
Try using some carb heat. =A0 =A0It will smo= oth out that engine significantly when LOP.

The warmer induction air does a much more uniform job of distributing the f= uel as vapor with less liquid drop outs in the induction plumbing.



-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of vtailjeff@aol.com
Sent: Tuesday, October 15, 2013 8:21 AM
To: lml@lancaironline.net
Subject: [LML] Re: LOP ops on O-360 A1A

Have you checked your baffling?

Sent from my iPad

On Oct 15, 2013, at 7:53 AM, Keith Smith <keith.smith@gmail.com> wrote:

> Hey all,
>
> I'm waiting for winter to come around but it seems like my O-360 A= 1A has been running warmer than usual, requiring me to power back very shor= tly after takeoff to avoid an excursion north of 425 degree CHT's.
>
> In any case, I know that LOP ops are hard to come by with an O-360 due= to poor fuel distribution. Indeed, my #4 cylinder peaks well before the ot= hers, making it tricky to get them LOP.
>
> I've been running in two modes...one is around 20 LOP to cool it d= own to around 385 CHT while the others run just slightly rich of peak. I ca= n do this without much effort, and under a wide range of throttle positions= , and density altitudes.
>
> On a recent flight, though, I found #1 and #3 settling on temps that w= ere just too high to be happy with. I would go well ROP to get them cooled,= but burned a lot of fuel in the process and still had a warm 4th cylinder = due to the fact that it runs quite a bit leaner. This was all done at 75% p= ower or less, btw, density altitude was well above 11k (I was at 11k and it= was +10C)
>
> Eventually, I tried something somewhat dramatic. I was determined to g= et ALL the cylinders LOP. I leaned relatively rapidly and ignored the disco= ncerting knocking/shuddering associated with the uneven amounts of power be= ing produced between the 4th cylinder and all the rest.
>
> It all happened a bit quickly, but with cylinder 1-3 roughly 20-40 LOP= and #4 70-90 LOP, the CHTs dropped like a stone, seemingly in seconds, dow= n to 380-385 across the board for #1-3 with #4 now in the 350-360 range. Wi= th careful fiddling of the mixture, and countless experiments with throttle= position, I got the vibration down to the point where it was barely notice= able. Eventually it just felt smooth...but I can't tell if I got used t= o it, or things just settled down, although I wouldn't think it was pos= sible.
>
> Final fuel flow was around 8.8-9.0 gph.
>
> Finally, living the LOP dream with my O-360 :)
>
> I tried repeating this later on, down low and wasn't able to repea= t it (ie, never got it smooth).
>
> So, it's elusive, but possibly doable under just the right circums= tances. Since I do long trips on a regular basis, I'm definitely intere= sted in making this work.
>
> Separately, I'll try to find out why it's running warmer in ge= neral. I did have a mag replaced, the other rebuilt, and 4 new plugs instal= led in the last year.
>
> Honestly, I'm going to try to save some clams and get this convert= ed to an IO-360 (didn't realize it was relatively inexpensive until my = mechanic suggested it), get balanced injectors and run LOP as SOP. The diff= erence in cooling really is staggering. I know I'm probably preaching t= o the choir, but I thought that O-360 owners might find it eye opening. Get= up high and give it a try if you have a 4 point engine monitor. You'll= know it's working when your leaning results in EGT and CHT's comin= g down :)
>
> The trip, btw, was N07-KFTW-KSAV-N07, around 2600nm.
>
> Keith

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