X-Virus-Scanned: clean according to Sophos on Logan.com From: "Patrick Panzera" Received: from mail-vc0-f171.google.com ([209.85.220.171] verified) by logan.com (CommuniGate Pro SMTP 6.0.9e) with ESMTPS id 6996170 for flyrotary@lancaironline.net; Wed, 23 Jul 2014 21:44:15 -0400 Received-SPF: none receiver=logan.com; client-ip=209.85.220.171; envelope-from=editor@contactmagazine.com Received: by mail-vc0-f171.google.com with SMTP id hq11so3804282vcb.2 for ; Wed, 23 Jul 2014 18:43:40 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:content-type; bh=6izb1IAlNwDf616L7ZWKapGzWvMxEJjaLeiBdPXVekI=; b=PBlmbafm3QrlNp9BeItYxYbxHsszbmUpjpZtczs0MmhxmbVyNAouRPo9PF+HdR09rl C9HN0KyML4iaHhCGyrAQxeRKkCvd84bNJs1HwZkaFZ5TR300dUSODbspApdJRA3yrbuZ FInf9pQIhRyfyn1LqpwKtq93mb0acZhdZ4WTzAtuyiQHYoClyYDOkpF+DTbuE8v5LLk/ PO9d4GI04IoRqrSvYdoaHfQnCkY4pFjy18r21n+FX4wvhZVzlUWMlNoOHExzgEZ7xEIp rma4tqI+56YVbllqdXvm2m3hS4PB8G3U/KDv6QK1Y8XCP7YInajT2fpeeDwBwvOb7CXB wfuA== X-Gm-Message-State: ALoCoQkxhd7SLHhgO9erUYHXgEpSWokpKlf1KQ7irBiiwnj6NFDiTh85yt/nOmZgxNqFFkTrxnzE MIME-Version: 1.0 X-Received: by 10.220.131.207 with SMTP id y15mr7145655vcs.71.1406164441201; Wed, 23 Jul 2014 18:14:01 -0700 (PDT) Received: by 10.221.49.202 with HTTP; Wed, 23 Jul 2014 18:14:01 -0700 (PDT) In-Reply-To: References: Date: Wed, 23 Jul 2014 18:14:01 -0700 Message-ID: Subject: Re: [FlyRotary] Re: Rv7 renises p port To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=001a11348c2e039a5304fee62cbd --001a11348c2e039a5304fee62cbd Content-Type: text/plain; charset=UTF-8 I wonder how much slip a helicopter has? ;) On Wed, Jul 23, 2014 at 5:45 PM, James Osborn wrote: > I don't know jack about slippage, but I think it is the percentage > difference between actual distance traveled and theoretical distance > traveled if your propeller corkscrewed through the air with no thrust. I > found a prop slip calculator online and for 86 inch pitch, 2.85 gear ratio, > 7000 rpm, 180 mph, I get 10% slip. Granted the calculator was for boat > propellers, but I don't think it matters as long as the units are correct. > There has to be some slip because there would be no thrust otherwise. So > what is considered a reasonable or good amount of slip? Using Bill's > numbers 86 inch pitch, 2.85 gear ratio, 7000 rpm, 200 mph, I get 0% slip. > That can't be right! > > > On Fri, Jul 4, 2014 at 7:19 AM, Bill Bradburry < > flyrotary@lancaironline.net> wrote: > >> Christian, >> >> It seems that you have a lot of prop slippage at cruise. I think that at >> that prop rpm you should be getting 200mph if you had no slippage. >> >> Bill >> >> -----Original Message----- >> From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] >> Sent: Thursday, July 03, 2014 4:01 PM >> To: Rotary motors in aircraft >> Subject: [FlyRotary] Rv7 renises p port >> >> Well hi all >> Just thought I'd throw out there the mods I,ve done to the renises in an >> rv7'. >> Well the p ported engine is now back in the plane and running well, over >> the >> standard short manifold that was originally in the plane I have gained >> around 400 static rpm, same prop and gearbox combo, 2.85 ratio, this >> equates >> to allot more hp at takeoff, just shy of 2300 prop rpm, I'm running a >> prince >> p tip prop at 68" x 86" pitch, >> At 8000 ft it is turning 7000 at 180 mph tas which is an improvement of 25 >> mph on previous tests, . So next plan is bigger prop and less pitch to let >> it rev to 7500 in strait and level. >> >> Cheers >> Christian >> Rv7 renises Aus >> >> >> Sent from my iPad >> -- >> Homepage: http://www.flyrotary.com/ >> Archive and UnSub: >> http://mail.lancaironline.net:81/lists/flyrotary/List.html >> >> >> -- >> Homepage: http://www.flyrotary.com/ >> Archive and UnSub: >> http://mail.lancaironline.net:81/lists/flyrotary/List.html >> > > --001a11348c2e039a5304fee62cbd Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
I wonder how much slip a helicopter has? =C2=A0;)


On Wed, Jul 23, = 2014 at 5:45 PM, James Osborn <flyrotary@lancaironline.net&g= t; wrote:
I don't know jack about= slippage, but I think it is the percentage difference between actual dista= nce traveled and theoretical distance traveled if your propeller corkscrewe= d through the air with no thrust. =C2=A0I found a prop slip calculator onli= ne and for 86 inch pitch, 2.85 gear ratio, 7000 rpm, 180 mph, I get 10% sli= p. =C2=A0Granted the calculator was for boat propellers, but I don't th= ink it matters as long as the units are correct. =C2=A0There has to be some= slip because there would be no thrust otherwise. =C2=A0So what is consider= ed a reasonable or good amount of slip? =C2=A0Using Bill's numbers 86 i= nch pitch, 2.85 gear ratio, 7000 rpm, 200 mph, I get 0% slip. =C2=A0That ca= n't be right!


On Fri, Jul 4= , 2014 at 7:19 AM, Bill Bradburry <flyrotary@lancaironline.net> wrote:
Christian,

It seems that you have a lot of prop slippage at cruise. =C2=A0I think that= at
that prop rpm you should be getting 200mph if you had no slippage.

Bill

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
Sent: Thursday, July 03, 2014 4:01 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Rv7 renises p port

Well hi all
Just thought I'd throw out there the mods I,ve done to the renises in a= n
rv7'.
Well the p ported engine is now back in the plane and running well, over th= e
standard short manifold that was originally in the plane I have gained
around 400 static rpm, same prop and gearbox combo, 2.85 ratio, this equate= s
to allot more hp at takeoff, just shy of 2300 prop rpm, I'm running a p= rince
p tip prop at 68" x 86" pitch,
At 8000 ft it is turning 7000 at 180 mph tas which is an improvement of 25<= br> mph on previous tests, . So next plan is bigger prop and less pitch to let<= br> it rev to 7500 in strait and level.

Cheers
Christian
Rv7 renises Aus


Sent from my iPad
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Homepage: =C2=A0htt= p://www.flyrotary.com/
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