X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from rv-out-0506.google.com ([209.85.198.225] verified) by logan.com (CommuniGate Pro SMTP 5.2.9) with ESMTP id 3272653 for flyrotary@lancaironline.net; Wed, 05 Nov 2008 10:17:46 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.198.225; envelope-from=rwstracy@gmail.com Received: by rv-out-0506.google.com with SMTP id f6so40557rvb.7 for ; Wed, 05 Nov 2008 07:17:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:sender :to:subject:in-reply-to:mime-version:content-type:references :x-google-sender-auth; bh=NI2GbcYnSbFXU51hvmXMZArATBBQ96/vxwVVklqOjh4=; b=nlAp/HoOurYu7vE39F7HM83O3hV/D3bogABBMcQH1DvTJvkbFMSQ4URLxSj2EFRvQ+ etxMzxrFove04q5z7SRSWJhMVXteWpKg/RQMZ/RZ63xG5Es7ua3NlWbrSYpPB+2kgsSp GK0fS2mdkJ/HY/wE2UTxkPsXiUHzNpE79BEGs= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:sender:to:subject:in-reply-to:mime-version :content-type:references:x-google-sender-auth; b=N/8lyPUbabxKBWYJtlnvOIg0glPrxDFmaq1ZXiVqju01FsDE4+UTrtugEsnx61r2S5 j2+06TgzKLr02Oji/y29COoolDWr50iqRwSie9MvE545L6YqF0xXyZYHPMyj7ub2bXB1 OPnLXf3ODOywrL9d6VBuWXOxEE8J5Ll2czhhg= Received: by 10.141.114.19 with SMTP id r19mr465149rvm.24.1225898230120; Wed, 05 Nov 2008 07:17:10 -0800 (PST) Received: by 10.141.41.18 with HTTP; Wed, 5 Nov 2008 07:17:10 -0800 (PST) Message-ID: <1b4b137c0811050717x2395d855mb4f47fb7f079e6c2@mail.gmail.com> Date: Wed, 5 Nov 2008 10:17:10 -0500 From: "Tracy Crook" Sender: rwstracy@gmail.com To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] single rotor performance In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_4114_24990541.1225898230103" References: X-Google-Sender-Auth: b16813dfe021f0cb ------=_Part_4114_24990541.1225898230103 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Thanks for the great data Richard, I overlooked your power chart at first glance. How did you vary the load to get those curves? Prop Pitch change I guess? I'm very surprised that there was so little change at 4000 but the increase at 6000 was well worth it. I'd still like to see a fixed pitch rpm measurement between the two configurations. Did you measure that? Tracy On Wed, Nov 5, 2008 at 9:40 AM, Richard Sohn wrote: > Another step in the right direction. > > In deciding which way to go with the intake for the single rotor, I ran two > tests. The first one with a short 8" long intake runner, and a second one > with a 24" runner. > The results are certainly not surprising, however, I had to check the > possible impact on idle characteristic. > Except for a different idle mixture setting, I was not able to detect a > difference in idle characteristics at 2000RPM. There is no need for lower > idle with a 3.33 : 1 gear ratio. If for any reason I want to go lower with > idle, I would have to increase the fly wheel inertia. With no load on the > engine it idles down to 1300RPM with the 8" runner. > The long runner also resulted in a 1" higher MAP over the short runner. > > The 24" runner as shown in the picture will in the final configuration be > at least 3" longer, because the carb has to com lower than it is now. > > The engine config is 12A rotor and housing using 1 1/2" p-port. > > The HP calculation is based on a bsfc of .5 . This is probably conservative > with EGT at 1700F and mixture ratio at 14.6 . > > Richard Sohn > N2071U > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > ------=_Part_4114_24990541.1225898230103 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Thanks for the great data  Richard,

I overlooked your power chart at first glance.  How did you vary the load to get those curves?  Prop Pitch change I guess?   I'm very surprised that there was so little change at 4000 but the increase at 6000 was well worth it. 

I'd still like to see a fixed pitch rpm measurement between the two configurations.  Did you measure that?


Tracy

On Wed, Nov 5, 2008 at 9:40 AM, Richard Sohn <res12@fairpoint.net> wrote:
Another step in the right direction.
 
In deciding which way to go with the intake for the single rotor, I ran two tests. The first one with a short 8" long intake runner, and a second one with a 24" runner.
The results are certainly not surprising, however, I had to check the possible impact on idle characteristic.
Except for a different idle mixture setting, I was not able to detect a difference in idle characteristics at 2000RPM. There is no need for lower idle with a 3.33 : 1 gear ratio. If for any reason I want to go lower with idle, I would have to increase the fly wheel inertia. With no load on the engine it idles down to 1300RPM with the 8" runner.
The long runner also resulted in a 1" higher MAP over the short runner.
 
The 24" runner as shown in the picture will in the final configuration be at least 3" longer, because the carb has to com lower than it is now.
 
The engine config is 12A rotor and housing using 1 1/2" p-port.
 
The HP calculation is based on a bsfc of .5 . This is probably conservative with EGT at 1700F and mixture ratio at 14.6 .
 
Richard Sohn
N2071U

--
Homepage:  http://www.flyrotary.com/
Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/List.html


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