X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 10 Apr 2006 22:13:51 -0400 Message-ID: X-Original-Return-Path: Received: from web34915.mail.mud.yahoo.com ([209.191.68.194] verified) by logan.com (CommuniGate Pro SMTP 5.0.9) with SMTP id 1063825 for lml@lancaironline.net; Mon, 10 Apr 2006 02:56:23 -0400 Received-SPF: none receiver=logan.com; client-ip=209.191.68.194; envelope-from=n103md@yahoo.com Received: (qmail 86914 invoked by uid 60001); 10 Apr 2006 06:55:12 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:Received:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=bu1KIYgJtMltHUvhXwhz1Qw7cZjRZgp7lJeZv2MVkQXvRxXKiTOgJ7FlNL4QePAYFaLVL8OkwAp6WoFxZCY/O9RT61O9LBTGymUjVG7M7vQej+3foZquqOB0eKLAoOGnDgB41KTkLtv8G525z2ipTt2YeTkOPaSYcZLBQ/SpmK8= ; X-Original-Message-ID: <20060410065512.86912.qmail@web34915.mail.mud.yahoo.com> Received: from [69.12.132.145] by web34915.mail.mud.yahoo.com via HTTP; Sun, 09 Apr 2006 23:55:12 PDT X-Original-Date: Sun, 9 Apr 2006 23:55:12 -0700 (PDT) From: bob mackey Subject: Re: [LML] fixed-pitch prop X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-245935404-1144652112=:86620" Content-Transfer-Encoding: 8bit --0-245935404-1144652112=:86620 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Grayhawk: your comments on Paul Lipps and his propellor drag might be seen as an uninformed attack. I highly pitched fixed prop has MUCH less drag that a typical C/S prop that reverts to flat pitch when the engine quits. My 235 has a 64x78 wood prop, and like Paul's has a glide ratio of well over 10:1 with the engine idling or with the mixture cutoff. I haven't measured it with the prop stopped. Also like Paul's aircraft, mine takes a while to stop on the runway. This is a definite disadvantage of a highly pitched fixed prop. It is also a challenge when descending in formation with draggier aircraft, including LNC2s with a flatter prop. Paul seems to be a pretty smart guy that knows a thing or three about prop drag. I don't think he was quoting from an advertisement, or resorting to numerical mumbo jumbo. Also, his prop is quite a bit different. The thin tips probably reduce gliding drag relative to my more ordinary thick wood prop. He did claim 15:1 with the engine idling and not with the prop stopped. That seems reasonable to me... and I've got a lot more hours without an engine than with. -bob mackey --------------------------------- Blab-away for as little as 1¢/min. Make PC-to-Phone Calls using Yahoo! Messenger with Voice. --0-245935404-1144652112=:86620 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Grayhawk: your comments on Paul Lipps and his propellor drag
might be seen as an uninformed attack. I highly pitched fixed
prop has MUCH less drag that a typical C/S prop that reverts
to flat pitch when the engine quits. My 235 has a 64x78 wood
prop, and like Paul's has a glide ratio of well over 10:1 with the
engine idling or with the mixture cutoff. I haven't measured it
with the prop stopped.

Also like Paul's aircraft, mine takes a while to stop on the runway.
This is a definite disadvantage of a highly pitched fixed prop.
It is also a challenge when descending in formation with draggier
aircraft, including LNC2s with a flatter prop.

Paul seems to be a pretty smart guy that knows a thing or three
about prop drag. I don't think he was quoting from an advertisement,
or resorting to numerical mumbo jumbo. Also, his prop is quite a bit
different. The thin tips probably reduce gliding drag relative to my
more ordinary thick  wood  prop.
He did claim 15:1 with the engine idling and not with the prop stopped.
That seems reasonable to me... and I've got a lot more hours without
an engine than with.

-bob mackey

 


Blab-away for as little as 1¢/min. Make PC-to-Phone Calls using Yahoo! Messenger with Voice. --0-245935404-1144652112=:86620--