X-CGP-ClamAV-Result: CLEAN X-VirusScanner: Niversoft's CGPClamav Helper v1.23.0 (ClamAV engine v0.103.0) X-Junk-Score: 0 [] X-KAS-Score: 0 [] From: "Matt Boiteau mattboiteau@gmail.com" Received: from mail-lf1-f48.google.com ([209.85.167.48] verified) by logan.com (CommuniGate Pro SMTP 6.3.5) with ESMTPS id 73782 for flyrotary@lancaironline.net; Sat, 05 Jun 2021 15:12:23 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.167.48; envelope-from=mattboiteau@gmail.com Received: by mail-lf1-f48.google.com with SMTP id w33so19202798lfu.7 for ; Sat, 05 Jun 2021 12:12:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=mj9RAcfJcBeENA4zJggBBuZT6Kqlm1YJ24lozgGXJRk=; b=ZJ46d+O1zAXJBBag9AYBycC31dNyXresoGn+VXDTaxhYLDhNL/FyoG/AD3hI+KgDZt eXO+TsNTXl/CL+EY46r9HJ2+zI47dzkZ3aXH/wZ+Z9B3rg58axF4aLS+kMXYdk3La/Su k3rzTVWNv+YnPP+bhM5cPtoQjVkefl8RP/YDk23mfi1MMCzM2KF3EUF9sfi04QPSVomF WBC4v7kzSOX1FmtwsaFUmvu0vg7Ef4P7ZL6IJeKOl0c2+uKaQENnob99NV3BYCA8JshR gL4gWnAysA35HlyCYv593Fn4tkBzWNUsO/iqoo0CXp+PXSM2+tcAEzbYxqB7I1OXPXOU Kaqw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=mj9RAcfJcBeENA4zJggBBuZT6Kqlm1YJ24lozgGXJRk=; b=WQ35l+st3YrxDPCdo84IlSvWrB28Tl/dueYrgPFQdY/sNlDMTOfI4SEOv+AssPsCqa f/0L8wmtrh2VXuac/FTd9BzCeZ8GmEY+3RbdxXqUgff+MRoMyiFvt5yY/nqSu/ZSJZgB 5fxf1oYurJ+goyz74ICooeEqqXjpxnRUBc1yssYD988eyImwpDV94SqsOqUVUvMLAlwI 7hZV4EcQwZTmCnoPvpJJJe3L0B8Ev+wtLLQVcDeeuvX56c0oiKKHxzLQQypS2QsSwYC1 tCIc1OXTJGq3IdUyjkqUW4yHc/qhFOPFzmw2b0czNoE3wSDFrQlOn5aUVSwModJ0SSLz xP9A== X-Gm-Message-State: AOAM533W4c0xot3VTb3zfU8VrMjPYyyPz5b8/R+jNsF8/WkYScmPkViE Ao/clzZ8Jytaff64Oq9uP7n+sk117zvlJyVFva8nvroCynQ= X-Google-Smtp-Source: ABdhPJyU2oYxIu0sy90rebqOJdNYfwzOEKJCbJ9XM+FlZlLXVARjq0DkgLhC3UcYZCQcbHyOlxhOQeGUsG3Tx+PbIiE= X-Received: by 2002:a19:6e41:: with SMTP id q1mr941984lfk.409.1622920325751; Sat, 05 Jun 2021 12:12:05 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: Date: Sat, 5 Jun 2021 15:11:54 -0400 Message-ID: Subject: Re: [FlyRotary] Re: Tuning To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="00000000000083e86d05c4099579" --00000000000083e86d05c4099579 Content-Type: text/plain; charset="UTF-8" Yeah I went up to 8000' feet the other day and did some simulated circuits. Was hoping someone would give me a good starting point to see if I'm on the right track. Yeah I don't know why Paul L got the machine shop to drill 2" p-ports. Seems quite large. - Matt Boiteau On Sat, Jun 5, 2021 at 11:46 AM Charlie England ceengland7@gmail.com < flyrotary@lancaironline.net> wrote: > Those that are already flying are much better equipped to answer the > tuning question, but IIRC, Tracy has talked about one of the 'problem > areas' of tuning that can't be tuned on the ground is the high rpm/low MAP > region as you'd see in a decent. Might be worth a dive into the archives to > see what he recommended. > > On port diameter: The 'conventional wisdom' is that you need to maintain > some (not well defined) level of air velocity in the manifold runners. So > it logically follows that the entire length should be the same diameter. > Some tuning techniques use a tapered runner that is smallest at the valve > (our intake port) so that the air is accelerating as it reaches the > combustion chamber, but seems to me that simply necking down the port at > the side of the block would just create a really bad flow separation at > that point. > > On 6/5/2021 9:51 AM, Matt Boiteau mattboiteau@gmail.com wrote: > > High power isn't an issue with timing. > > I'm trying to understand when you are on base/final and your prop is > driving the engine. > > Do we treat it like coasting down hill in a car? > > Under 40kpa and 4500rpm, what timing does Tracy computer use? > > On Fri., Jun. 4, 2021, 09:47 Matt Boiteau mattboiteau@gmail.com, < > flyrotary@lancaironline.net> wrote: > >> Sorry I missed all the replies here. >> >> Charlie - I'm measuring both in/out of oil and coolant. Usually when I >> list the temp numbers, I try to say which one it is. Sorry about that. >> >> The P-Port Renesis engine that I have, got 2" p-ports from Paul. Which >> sounds like they are too big? I wonder how I can bring them down to 1.75"? >> Is the inlet to the engine more important, or the whole length of the >> runners to be 1.75"? >> >> I still don't have a good answer for timing tables for the Rx8. Having a >> bit trouble tuning for the low RPM's for downwind / final. I know for cars, >> you can cut the fuel and raise the timing to coast downhill. Not sure for >> airplanes, since the prop is driving the engine, how we tune for that. >> Right now I have 38degree timing for descending. I wonder if I should drop >> that down to the low 30s and not try to lean it out like a car. >> >> - Matt Boiteau >> -- >> Homepage: http://www.flyrotary.com/ >> Archive and UnSub: >> http://mail.lancaironline.net:81/lists/flyrotary/List.html >> > > > > Virus-free. > www.avast.com > > <#m_-804428851570926246_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > --00000000000083e86d05c4099579 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Yeah I went up to 8000' feet the other day and did som= e simulated circuits. Was hoping someone=C2=A0would give me a good starting= point to see if I'm on the right track.

Yeah I don't know w= hy Paul L got the machine shop to drill 2" p-ports. Seems quite large.=

- Matt= Boiteau


On Sat, Jun 5, 2021 at 11:46 AM C= harlie England ceengland7@gmail.com= <flyrotary@lancairon= line.net> wrote:
=20 =20 =20
Those that are already flying are much better equipped to answer the tuning question, but IIRC, Tracy has talked about one of the 'problem areas' of tuning that can= 9;t be tuned on the ground=C2=A0 is the high rpm/low MAP region as you'd= see in a decent. Might be worth a dive into the archives to see what he recommended.

On port diameter: The 'conventional wisdom' is that you need = to maintain some (not well defined) level of air velocity in the manifold runners. So it logically follows that the entire length should be the same diameter. Some tuning techniques use a tapered runner that is smallest at the valve (our intake port) so that the air is accelerating as it reaches the combustion chamber, but seems to me that simply necking down the port at the side of the block would just create a really bad flow separation at that point.

On 6/5/2021 9:51 AM, Matt Boiteau mattboiteau@gmail.com wrote:
=20
High power isn't an issue with timing.

I'm trying to understand when you are on base/final and your prop is driving the engine.

Do we treat it like coasting down hill in a car?=C2=A0

Under 40kpa and 4500rpm, what timing does Tracy computer use?

On Fri., Jun. 4, 2021, 09:47 Matt Boiteau mattboiteau@gmail.com, <flyrotary@lancaironline.net> wrote:
=C2=A0 Sorry I missed all the replies here.

Charlie - I'm measuring=C2=A0both in/out of oil and co= olant. Usually when I list the temp numbers, I try to say which one it is. Sorry about that.

The P-Port Renesis engine that I have, got 2" p-ports fr= om Paul. Which sounds like they are too big? I wonder how I can bring them down to 1.75"? Is the inlet to the engine more important, or the whole length of the runners to be 1.75"?

I still don't have a good answer for timing tables for th= e Rx8. Having a bit trouble tuning for the low RPM's for downwind / final. I know for cars, you can cut the fuel and raise the timing to coast downhill. Not sure for airplanes, since the prop is driving the engine, how we tune for that. Right now I have 38degree timing for descending. I wonder if I should drop that down to the low 30s and not try to lean it out like a car.

- Matt Boiteau
--
Homepage:=C2=A0 http://www.flyrotary.com/
Archive and UnSub:=C2=A0 =C2=A0http://mail.lancaironline.net:81/lists/flyrotary/List.html<= br>


3D"" Virus-free. www.avast.com=
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