X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imf16aec.mail.bellsouth.net ([205.152.59.64] verified) by logan.com (CommuniGate Pro SMTP 5.0.4) with ESMTP id 889073 for flyrotary@lancaironline.net; Mon, 19 Dec 2005 18:44:13 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.64; envelope-from=atlasyts@bellsouth.net Received: from ibm58aec.bellsouth.net ([65.11.41.212]) by imf16aec.mail.bellsouth.net with ESMTP id <20051219234329.UIDY2154.imf16aec.mail.bellsouth.net@ibm58aec.bellsouth.net> for ; Mon, 19 Dec 2005 18:43:29 -0500 Received: from [192.168.0.100] (really [65.11.41.212]) by ibm58aec.bellsouth.net with ESMTP id <20051219234328.QLBF27766.ibm58aec.bellsouth.net@[192.168.0.100]> for ; Mon, 19 Dec 2005 18:43:29 -0500 Mime-Version: 1.0 (Apple Message framework v746.2) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-7--37662378 Message-Id: <9A628C97-3CC3-4471-A503-C9364BDBB6A1@bellsouth.net> From: Bulent Aliev Subject: Re: [FlyRotary] Re: Props Date: Mon, 19 Dec 2005 18:44:03 -0500 To: "Rotary motors in aircraft" X-Mailer: Apple Mail (2.746.2) --Apple-Mail-7--37662378 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Thanks Dave. it makes me feel better now that I know I was wrong. My problem now is: I can spin my "monster prop" (static) up-to 4000RPM and 50" MP I don't think I can get much more in motion and may not get enough rpm for flight. I'll see first how much difference it will make on fast taxi. John Slade also will bring his Performance prop one day, so we can compare them. BTW the prop tip speed formula given to me was: Prop D" x 3.1416 x RPM divided by 720 Buly On Dec 19, 2005, at 6:06 PM, David Leonard wrote: > Oh, BTW Bully. You will also note that at 6000 RPM the prop is > doing 2750 which a lot of certified props will turn, even if 74"long. > > Also, short prop are not necessarily less efficient, its just that > the speed of peak efficiency is shifted to a higher airspeed, and > probably that peak is a little more narrow. > > Dave Leonard > > > On 12/19/05, Buly wrote: > Yesterday somebody gave me the formulas to calculate the prop tip > speed. I did some calculations and looks like us with the 2.17 > redrives are kind of painted in the corner. Hope I'm wrong, but if I > want to keep the tips from going supersonic, I have to cut down the > prop to 64" or keep the engine below 5500 RPM. The choice is either > inefficient prop and adequate power, or efficient long prop and not > getting all the power from the engine? Am I wrong? > Buly > atlasyts@bellsouth.net > > > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ > > > > -- > Dave Leonard > Turbo Rotary RV-6 N4VY > http://members.aol.com/_ht_a/rotaryroster/index.html > http://members.aol.com/_ht_a/vp4skydoc/index.html Bulent Aliev atlasyts@bellsouth.net http://home.bellsouth.net/p/s/community.dll? ep=16&ext=1&groupid=164323&ck= --Apple-Mail-7--37662378 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 Thanks Dave. it makes me feel = better now that I know I was wrong. My problem now is: I can spin my = "monster prop" (static) up-to 4000RPM and 50" MP I don't think I can get = much more in motion and may not get enough rpm for flight. I'll see = first how much difference it will make on fast taxi. John Slade also = will bring his Performance prop one day, so we can compare them.
BTW = the prop tip speed formula given to me was:
Prop D" x 3.1416 x = RPM divided by 720
Buly

On Dec = 19, 2005, at 6:06 PM, David Leonard wrote:

Oh, = BTW Bully.=A0 You will also note that at 6000 RPM the prop is doing 2750 = which a lot of certified props will turn, even if 74"long.
=
=A0
Also, short prop are not necessarily less efficient, = its just that the speed of peak efficiency is shifted to a higher = airspeed, and probably that peak is a little more narrow.
=
=A0
Dave Leonard

=A0
On 12/19/05, Buly = <atlasyts@bellsouth.net> = wrote:
Yesterday = somebody gave me the formulas to calculate the prop tip
speed. I did = some calculations and looks like us with the 2.17
redrives are kind = of painted in the corner. Hope I'm wrong, but if I
want to keep the = tips from going supersonic, I have to cut down the
prop to 64" or = keep the engine below 5500 RPM. The choice is either
inefficient = prop and adequate power, or efficient long prop and not
getting all = the power from the engine? Am I wrong?
Buly
atlasyts@bellsouth.net

<= BR>

--
Homepage:=A0=A0http://www.flyrotary.com/
Archiv= e and UnSub:=A0=A0 http://mail.lancai= ronline.net/lists/flyrotary/



--
Dave Leonard
Turbo Rotary RV-6 N4VY
http://membe= rs.aol.com/_ht_a/rotaryroster/index.html
= http://members.aol.com/_ht_a/vp4skydoc/index.html
Bulent = Aliev
http://home.bellsouth.net/p/s/community.dll?ep=3D16&= ext=3D1&groupid=3D164323&ck=3D

=

= --Apple-Mail-7--37662378--