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" <kenbjo...@cinci.rr.com> 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" <k...@bigpond.com> > To: "KRnet" <kr...@mylist.net> > 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
