X-Virus-Scanned: clean according to Sophos on Logan.com From: "James Osborn" Received: from mail-oa0-f47.google.com ([209.85.219.47] verified) by logan.com (CommuniGate Pro SMTP 6.0.9e) with ESMTPS id 6996125 for flyrotary@lancaironline.net; Wed, 23 Jul 2014 20:45:43 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.219.47; envelope-from=rxcited@gmail.com Received: by mail-oa0-f47.google.com with SMTP id g18so2726742oah.20 for ; Wed, 23 Jul 2014 17:45:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=943zEwHi05F2ZOSvAMtD9uWDhYWqcqu/nd6ejRUZXXE=; b=rQXU5LRv6zZkYqXqqvCqcbjM9vFCoMR406c8KVaFd0uJWR5Q2HCpyCRQmy9QURrPUc JJ36sjw4Uy2f/Uc4ub0YO/lhFO9DMlP2b2aLqaMFTZmd1sJec95KLyMt/F4KWoTTDpLO Qt4D2xYFgsLMcbf+vRdvn7FVwuq0pCp5OyA07zPkvSREKfIUSKr7Wsnf32IerPUfT4Ex IEdSiydYoDQ0qX20wO2TYaMXT9HjQDKefdzAOhagMr22VTuoeaKSf+f1+37v5TYb2h+1 Wp1yYU1fJ5LRjfpWolOGmkR67g9aSso++YFA3eEJkokdmiKEfwbVmJ4qef4ijwaDRaJ4 vhCw== MIME-Version: 1.0 X-Received: by 10.60.140.234 with SMTP id rj10mr7613689oeb.6.1406162706870; Wed, 23 Jul 2014 17:45:06 -0700 (PDT) Received: by 10.202.107.77 with HTTP; Wed, 23 Jul 2014 17:45:06 -0700 (PDT) In-Reply-To: References: Date: Wed, 23 Jul 2014 17:45:06 -0700 Message-ID: Subject: Re: [FlyRotary] Re: Rv7 renises p port To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=047d7b4725eaa3b67504fee5c4fa --047d7b4725eaa3b67504fee5c4fa Content-Type: text/plain; charset=UTF-8 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 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 > --047d7b4725eaa3b67504fee5c4fa Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
I don't know jack about slippage, but I think it is th= e percentage difference between actual distance traveled and theoretical di= stance traveled if your propeller corkscrewed through the air with no thrus= t. =C2=A0I found a prop slip calculator online and for 86 inch pitch, 2.85 = gear ratio, 7000 rpm, 180 mph, I get 10% slip. =C2=A0Granted the calculator= was for boat propellers, but I don't think it matters as long as the u= nits are correct. =C2=A0There has to be some slip because there would be no= thrust otherwise. =C2=A0So what is considered a reasonable or good amount = of slip? =C2=A0Using Bill's numbers 86 inch pitch, 2.85 gear ratio, 700= 0 rpm, 200 mph, I get 0% slip. =C2=A0That 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. =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
--
Homepage: =C2=A0htt= p://www.flyrotary.com/
Archive and UnSub:
http://mail.lancaironline.net:81/lists/flyrotary/List.html


--
Homepage: =C2=A0htt= p://www.flyrotary.com/
Archive and UnSub: =C2=A0 http://mail.lancaironline.net:81/li= sts/flyrotary/List.html

--047d7b4725eaa3b67504fee5c4fa--