X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imf24aec.mail.bellsouth.net ([205.152.59.72] verified) by logan.com (CommuniGate Pro SMTP 5.0.4) with ESMTP id 889285 for flyrotary@lancaironline.net; Mon, 19 Dec 2005 21:55:05 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.72; envelope-from=atlasyts@bellsouth.net Received: from ibm68aec.bellsouth.net ([65.2.250.50]) by imf24aec.mail.bellsouth.net with ESMTP id <20051220025421.KHPU9737.imf24aec.mail.bellsouth.net@ibm68aec.bellsouth.net> for ; Mon, 19 Dec 2005 21:54:21 -0500 Received: from [192.168.0.100] (really [65.2.250.50]) by ibm68aec.bellsouth.net with ESMTP id <20051220025411.CEPB28650.ibm68aec.bellsouth.net@[192.168.0.100]> for ; Mon, 19 Dec 2005 21:54:11 -0500 Mime-Version: 1.0 (Apple Message framework v746.2) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-19--26199451 Message-Id: <9922DC01-E192-443F-866A-AA82A1D03A97@bellsouth.net> From: Bulent Aliev Subject: Re: [FlyRotary] Re: Props Date: Mon, 19 Dec 2005 21:55:06 -0500 To: "Rotary motors in aircraft" X-Mailer: Apple Mail (2.746.2) --Apple-Mail-19--26199451 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed AHA! That's it. It's scarry they let me fly airplanes :) Thanks Bob. Buly On Dec 19, 2005, at 7:17 PM, Bob White wrote: > Hi Buly, > > That formula will give speed in fps. > > 3.14*64*(5500/2.17) = 509346 > > 508346/720 = 707 fps > > 88 fps = 60 mph so 707 fps = 482 mph which is well below the speed of > sound. > > Bob W. > > On Mon, 19 Dec 2005 18:44:03 -0500 > Bulent Aliev wrote: > >> 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= >> >> >> > > > -- > http://www.bob-white.com > N93BD - Rotary Powered BD-4 (Projected engine start - maybe next week) > Custom Cables for your rotary installation - > http://www.roblinphoto.com/shop/ > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ Bulent "Buly" Aliev http://home.bellsouth.net/p/s/community.dll? ep=16&ext=1&groupid=164323&ck= --Apple-Mail-19--26199451 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 AHA! That's it. It's scarry they = let me fly airplanes :) Thanks Bob.
Buly

On = Dec 19, 2005, at 7:17 PM, Bob White wrote:

Hi Buly,

That formula will give speed in = fps.

3.14*64*(5500/2.17) =3D 509346


88 fps =3D 60 mph so 707 fps =3D = 482 mph which is well below the speed of

Bob W.

On Mon, 19 Dec 2005 18:44:03 = -0500
Bulent Aliev <atlasyts@bellsouth.net> = wrote:

=
Thanks Dave. it makes me = feel better now that I know I was wrong. My =A0
problem = now is: I can spin my "monster prop" (static) up-to 4000RPM =A0
and 50" = MP I don't think I can get much more in motion and may not =A0
get = enough rpm for flight. I'll see first how much difference it will =A0
make on = fast taxi. John Slade also will bring his Performance prop =A0
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

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 =A0
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 =A0
the speed of peak efficiency is shifted to a higher = airspeed, and =A0
probably that peak is a little more = narrow.

Dave Leonard


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




--



--=A0
Dave = Leonard
Turbo Rotary RV-6 N4VY

Bulent = Aliev
http://home.bellsout= h.net/p/s/community.dll?=A0





--=A0
N93BD - Rotary Powered BD-4 (Projected engine start = - maybe next week)
Custom Cables for your = rotary installation -

--

= --Apple-Mail-19--26199451--