X-Virus-Scanned: clean according to Sophos on Logan.com From: "James R. Osborn" Received: from mail-pa0-f50.google.com ([209.85.220.50] verified) by logan.com (CommuniGate Pro SMTP 6.1.6) with ESMTPS id 8057708 for flyrotary@lancaironline.net; Thu, 08 Oct 2015 18:20:57 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.220.50; envelope-from=rxcited@gmail.com Received: by pablk4 with SMTP id lk4so66201603pab.3 for ; Thu, 08 Oct 2015 15:20:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:content-type:message-id:mime-version:subject:date:references :to:in-reply-to; bh=f3SMUauqLI48xhwQ3mQ91O8/YrobxwOFAz6GVzsoaVs=; b=iE0xkLnvUWYLz7iA58TuEY82wlrGlhazkw/ZSCE/oy4SVvXV9N8BrrKWRSCkBxvgrO jNiruZ94pT5ZhaJFLf+aJZY4dNxBywA5ZIGWGibiwabV5VcV0Js5M/zAU2eVwuQ7DCHG 2u9snrwuiVuxUHwGdiqHlMWPAyrubRs1g8ulsN5f4rW3BrWECXmfKtwyu2POeswrrS8n hfSIrTgHKOw5oSMZbhKOr5J9ozFeq/Hzhx0yQY6ICa3cbF/CEpnU9LQyvS1107Wfh6Nz RkRhnGg4fhofR94BlhEctJSyswWoq/2xJMZ/ZW6/uEHmlUFxPWvZw/bP/8b4HI9Vmran 3d4A== X-Received: by 10.66.163.228 with SMTP id yl4mr10722679pab.112.1444342821186; Thu, 08 Oct 2015 15:20:21 -0700 (PDT) Return-Path: Received: from jrosborn-m76.lbl.gov (jrosborn-m76.lbl.gov. [128.3.128.169]) by smtp.gmail.com with ESMTPSA id rz9sm47404980pbb.61.2015.10.08.15.20.19 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 08 Oct 2015 15:20:20 -0700 (PDT) Content-Type: multipart/alternative; boundary="Apple-Mail=_0F9F179B-1F7B-4132-86AD-3E7485B30644" Message-Id: <27460CC6-730B-4BA8-84D3-FAEC5743DDD5@gmail.com> Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2104\)) Subject: Re: [FlyRotary] To P or not... Date: Thu, 8 Oct 2015 15:20:17 -0700 References: To: Rotary motors in aircraft In-Reply-To: X-Mailer: Apple Mail (2.2104) --Apple-Mail=_0F9F179B-1F7B-4132-86AD-3E7485B30644 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 Tom is that a PP 3 rotor? If side port, is it ported in any way? I am not denying all that you say. But 2 rotors are way more readily = available and my friend has one already, allegedly basically brand new. = We do need to do some tests on it, but if it is a good motor, I think he = will want to avoid trying to source a 3 rotor or build a PP out of his 2 = rotor. But he thinks he needs more power, hence the turbo option. Question about turbo control for you all. If your goal is very modest = boost at sea level, but normalizing at altitude, can you not just use a = boost controller and set a MAP as in manifold absolute pressure and = stick to that? Say you set it for 3 psi (roughly 18 psi absolute), that = would be very modest boost at sea level, but at altitude, the turbo = would try to stick to that - maybe it is 6 psi or whatever over = atmospheric, but the same absolute pressure. Is there any reason to = feel you are stressing the motor if you are sticking to reasonable boost = like that? =E2=80=94 James > On Oct 7, 2015, at 12:33 PM, Tom Mann = wrote: >=20 > Whenever the topic comes up about adding a turbo to a Rotary I go back = to what was the reasoning I used when making the decision to go Rotary = in the first place. > My reasoning was to eliminate as much mechanical complexity as I = possibly could. If I added a turbo then the level of complexity (and = weight) went up. > I reasoned that if I needed (or just plain wanted) additional power, I = would just add another rotor. That actually gives me more power that the = turbo for where I need it most and the weight comparison is negligible = for the trade-off in power/complexity. > =20 > I believe that a 2 rotor (using Mistral Engines as a benchmark) = produces 190hp N/A (291 lbs) vs. 230hp Turbo (328 lb). The three rotor = generates 300 hp @ 375 lb so yes, it=E2=80=99s it=E2=80=99s roughly +50 = lbs but +70 hp as well without a significant increase in complexity. > =20 > I opted for the 3-rotor solution. Less things to go wrong (which is = important to me.) > =20 > T Mann > =20 --Apple-Mail=_0F9F179B-1F7B-4132-86AD-3E7485B30644 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 Tom is that a PP 3 rotor?  If side port, is it ported in = any way?

I am not = denying all that you say.  But 2 rotors are way more readily = available and my friend has one already, allegedly basically brand new. =  We do need to do some tests on it, but if it is a good motor, I = think he will want to avoid trying to source a 3 rotor or build a PP out = of his 2 rotor.  But he thinks he needs more power, hence the turbo = option.

Question= about turbo control for you all.  If your goal is very modest = boost at sea level, but normalizing at altitude, can you not just use a = boost controller and set a MAP as in manifold absolute pressure and = stick to that?  Say you set it for 3 psi (roughly 18 psi absolute), = that would be very modest boost at sea level, but at altitude, the turbo = would try to stick to that - maybe it is 6 psi or whatever over = atmospheric, but the same absolute pressure.  Is there any reason = to feel you are stressing the motor if you are sticking to reasonable = boost like that?

=E2=80=94 James

On Oct 7, 2015, at 12:33 PM, Tom Mann <flyrotary@lancaironline.net> wrote:

Whenever the = topic comes up about adding a turbo=20 to a Rotary I go back to what was the reasoning I used when making the = decision=20 to go Rotary in the first place.
My reasoning = was to eliminate as much mechanical=20 complexity as I possibly could. If I added a turbo then the level of = complexity=20 (and weight) went up.
I reasoned = that if I needed (or just plain wanted)=20 additional power, I would just add another rotor. That actually gives me = more=20 power that the turbo for where I need it most and the weight comparison = is=20 negligible for the trade-off in power/complexity.
 
I believe = that a 2 rotor (using Mistral Engines as=20 a benchmark) produces 190hp N/A (291 lbs) vs. 230hp Turbo (328 lb). The = three=20 rotor generates 300 hp @ 375 lb so yes, it=E2=80=99s it=E2=80=99s = roughly +50 lbs but +70 hp as=20 well without a significant increase in complexity.
 
I opted for = the 3-rotor solution. Less things to=20 go wrong (which is important to me.)
 
T = Mann
 

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