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: "Charlie England ceengland7@gmail.com" Received: from mail-ot1-f41.google.com ([209.85.210.41] verified) by logan.com (CommuniGate Pro SMTP 6.3.5) with ESMTPS id 73456 for flyrotary@lancaironline.net; Sat, 05 Jun 2021 11:46:23 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.210.41; envelope-from=ceengland7@gmail.com Received: by mail-ot1-f41.google.com with SMTP id 69-20020a9d0a4b0000b02902ed42f141e1so12184505otg.2 for ; Sat, 05 Jun 2021 08:46:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language; bh=p8o0ggnLr9kSr2mtKmPE6Ym3W42fdlqheux4h3VUMJ8=; b=TIPAuhxo/3eGzxMO31VBlnQIH3aWv7J7PnzVDOTm/dui/CKlbVjVmP4HltbL945h13 tVz6s5FT7vRFYLrV9YKj9C64LL3TzLo4QQp/wdZ78XlalsJSaG4EOHa1ZjZfNPRR/JBD 7ViIql4WtCa96PpuG2KYJ7M//pu6/Kv2CHsqz+6TOt7lc/6GSEaXm8eiANSR0wN6PcC4 uY+ftqVeEMpqIB0SUb8kwFpZkFzI88l1hLBxYFm/xx+WPlsITRseLpC+BOWnraXGQPMn ScTAEv4TTBvfUpA7DbNVVDOQIT8mM202Pm/l86RfzbcUkY/qoNgQrEVikou2dwTyq/SY Nn5Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language; bh=p8o0ggnLr9kSr2mtKmPE6Ym3W42fdlqheux4h3VUMJ8=; b=Q5sg1YCk0QhSvc4HNqHvjv8zmplKXKhtm7BqvffvTAqUeJ+beZaFUTUjIDHYcja+9n vV+3hKsTQMCJ3PgNoxQ4lP2TOCONuTbSTpFbuLja9BrpuMD0exElg3KZlUz26nPQj8su H3gNNKPc27RAQkx8kShVPeDQNMVlmkqO7qmdUp4FMcfucqSx1dDF0jN2r3Btzg2D2KSy rf2UwJ9setXtlZRP9CykjlxoAsYEQ3A1j8xgDotp2k2gD9UiXRLC2GpBdhRXiBNmewUD 8Yu2XvYXkuHjoAKt6rLGB8AijUF+AuAriO+gWtPty4gKVZhIsW1YLAGE/Mum5/LvQhPc UoLQ== X-Gm-Message-State: AOAM530Ms97WNbKp9YqO53E0MnpIjnPIAOrU1cor70ITQQoHAqcdqFMG pfrXuiM7CuPkg30vMWsHb8En9UOYFak= X-Google-Smtp-Source: ABdhPJxQeFNzlvsQGNtTiipCbynkVhmRF6jNQwBsJ1L/glrbaHM+WtlpKz7VKhHNT15L8H3sTbicfQ== X-Received: by 2002:a05:6830:1bd7:: with SMTP id v23mr7907285ota.259.1622907965925; Sat, 05 Jun 2021 08:46:05 -0700 (PDT) Return-Path: Received: from ?IPv6:::1? ([2607:fb90:d04a:89ea:1497:b16e:8b99:a81e]) by smtp.googlemail.com with ESMTPSA id p204sm1138463oia.43.2021.06.05.08.46.03 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sat, 05 Jun 2021 08:46:05 -0700 (PDT) Subject: Re: [FlyRotary] Re: Tuning To: Rotary motors in aircraft References: Message-ID: <3dcc271e-2835-bfe3-a122-218295dc122e@gmail.com> Date: Sat, 5 Jun 2021 10:49:35 -0500 User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/alternative; boundary="------------43D8B94D72A88F2B915EDAA4" Content-Language: en-US X-Antivirus: Avast (VPS 210605-2, 06/05/2021), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. --------------43D8B94D72A88F2B915EDAA4 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit 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 > , > 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 > > -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus --------------43D8B94D72A88F2B915EDAA4 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit
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


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