That is exactly right on the drag created by a windmilling prop....It is about the same as bolting a piece of plywood on the nose that is the equivalant of the rotational disc of the prop. Next time your in a twin, shut one down and try flying with it windmilling and then feather it and you will quickly discover the difference!
RG "Golden, Kevin" <kevin.gol...@churchdwight.com> wrote: A windmilling prop does more than disturb air over the airframe. A windmilling prop will cause a huge amount of drag that is NEAR equal to the rotational disc of the prop. Not to worry. I haven't seen a VW or corvair windmill. Lycoming and Continentals will. Kevin. -----Original Message----- From: Dennis Mingear [mailto:dennisming...@yahoo.com] Sent: Friday, June 17, 2005 9:02 AM To: KRnet Subject: Re: KR> glide rato.. If the prop stops in a horizontal position it will disturb the airflow over the wing, making it seem smaller than it actually is, this will reduce the planes L/D. If the prop stops vertically the airflow over the wing is not disturbed and you have more effective wing area, producing more lift, which improves the planes L/D. If the prop is windmilling it is intermittantly disturbing the airflow over the wing which is hurting the wings ability to produce lift and hurting the planes L/D. Denny ... --- "Kenneth B. Jones" wrote: > Perhaps the stopped prop is less drag because it's > stalled. > > Below is data taken from my flight test. My idle > setting was about 800 to > 900 rpm, a little high, at the time. Speeds are > indicated knots. My plane > stalls at about 50 knots indicated so I didn't check > the glide below 60 kts. > Surely the ratio will start back the other way > before it stalls. I have a > KR-2 with Diehl wings, 3 blade Warp drive taper > blade 58" prop set at 19.5 > degrees at the tip, A65, empty weight is 623 lbs., > full fuel is 14 gal and I > weigh about 180. > > Glide > Speed Descent Distance Glide > kts ft/min NM/1000 ft. Ratio > 60 400 2.50 15.18 > 65 442.5 2.45 12.93 > 70 525 2.22 11.73 > 75 625 2.00 10.56 > 80 750 1.78 9.39 > 85 800 1.77 9.35 > 90 900 1.67 8.80 > 95 1100 1.44 7.60 > 100 1500 1.11 5.87 > > > BTW, Bill's 2.5 miles per 1000 ft altitude is a > glide ratio of 13.2 : 1 (if > I calculated correctly). > > Ken Jones, kenbjo...@cinci.rr.com > Sharonville, OH > N5834, aka The Porkopolis Flying Pig > > ----- Original Message ----- > From: "Barry Kruyssen" > To: "KRnet" > Sent: Thursday, June 16, 2005 6:31 PM > Subject: Re: KR> what a day./ glide rato.. > > > > > > ----- Original Message ----- From: larry flesner > I doubt if a stopped > > propeller is going to triple that number > > > > A stopped prop actually produces less drag, don't > know the reason but have > > tried it in self launch gliders (without > feathering the prop) both idling > > engine and stoped, there is noticeably less drag > when the prop was > > stopped. Also it is better for the prop to stop > vertically so any > > vortices from the prop don't upset the air flow > over the wing, so I'm told > > but I couldn't tell the difference :-) > > > > regards > > Barry Kruyssen > > > > > _______________________________________ > Search the KRnet Archives at > http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to > krnet-le...@mylist.net > please see other KRnet info at > http://www.krnet.org/info.html > "I can train a monkey to wave an American flag. That does not make the monkey patriotic." Scott Ritter __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com _______________________________________ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html *The information contained in this message may be confidential and/or subject to legal privilege, and is for the use of the intended addressee only. Any unauthorized use, dissemination or copying of the information in this message is strictly prohibited. If you have received this message in error, please notify the sender immediately and delete this message.* _______________________________________ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html
