X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 27 Jan 2013 06:59:24 -0500 Message-ID: X-Original-Return-Path: Received: from mail-gh0-f172.google.com ([209.85.160.172] verified) by logan.com (CommuniGate Pro SMTP 6.0.1) with ESMTPS id 6030981 for lml@lancaironline.net; Sat, 26 Jan 2013 16:05:41 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.160.172; envelope-from=pjdmiller@gmail.com Received: by mail-gh0-f172.google.com with SMTP id z22so236408ghb.3 for ; Sat, 26 Jan 2013 13:05:05 -0800 (PST) X-Received: by 10.236.123.109 with SMTP id u73mr9207580yhh.108.1359234305605; Sat, 26 Jan 2013 13:05:05 -0800 (PST) X-Original-Return-Path: Received: from pjdms-mbp.cfl.rr.com ([68.202.59.203]) by mx.google.com with ESMTPS id b54sm5129349yhj.19.2013.01.26.13.05.03 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sat, 26 Jan 2013 13:05:04 -0800 (PST) From: Paul Miller Content-Type: multipart/alternative; boundary="Apple-Mail=_45DB0471-C15C-44A0-973A-05E7DD81A7EA" X-Original-Message-Id: Mime-Version: 1.0 (Mac OS X Mail 6.2 \(1499\)) Subject: Re: [LML] Re: Prop efficiency -- Hartzell X-Original-Date: Sat, 26 Jan 2013 16:05:01 -0500 References: X-Original-To: "Lancair Mailing List" In-Reply-To: X-Mailer: Apple Mail (2.1499) --Apple-Mail=_45DB0471-C15C-44A0-973A-05E7DD81A7EA Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Regarding efficiency. You probably know our Legacy prop is cut back 3 = inches in diameter from the original full size Hartzell blade for nose = clearance. The guys here at Spruce have switched their SX300 = (Swearingen) to the Hartzell Legacy prop but uncut--so they get the = extra 3 inches in diameter. Some are running the IO540, some IO580. = The Hartzell is getting those guys an extra 5-7 knots and possibly more = versus the non-Legacy prop. I am told by the fellow doing some of the testing for Hartzell that if = the Legacy had the extra 3 inches diameter we would also benefit. I = don't know the figure. I don't know if it would be more than flap = hinge redesigns (read: fairings for us low IQs) but the question that = comes to mind: What factors have to be considered for a 3 inch larger = diameter Legacy prop? =20 Some things that come to mind: 1) Hartzell approval 2) prop clearance with flat strut and tire (not enough now for a larger = prop) 3) dynamics--how do the flight characteristics change and would tests be = required 4) Is there a benefit Feel free to start a new thread if someone has thoughts. Paul Legacy On 2013-01-26, at 2:24 PM, vtailjeff@aol.com wrote: > Charley, >=20 > I would like that! >=20 > Jeff >=20 > Sent from my iPad >=20 > On Jan 26, 2013, at 1:07 AM, Charles Brown = wrote: >=20 >> I have Hartzell's efficiency analysis for their 3-blade and 2-blade = props for the Legacy / IO550, if anyone's interested. (I suspect that = they would apply equally to any airframe and engine combination). >>=20 >>=20 >> On Jan 25, 2013, at 1:32 PM, Bill Bradburry wrote: >>=20 >> Fred, >>=20 >> I have never been great at reading graphs, but the diagonal line is = airspeed, not HP corrected for prop efficiency. That is the vertical = line. Or am I wrong?? >>=20 >> How do you do this if you have an alternative engine and have no idea = of what your HP is? It seems that you are guessing about the prop = efficiency and I would have to do the same for HP. Perhaps if someone = gets a FP drag number for the Lancair Legacy FG, I could work backwards = and find the HP? >>=20 >> Bill >>=20 >>=20 >>=20 --Apple-Mail=_45DB0471-C15C-44A0-973A-05E7DD81A7EA Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii vtailjeff@aol.com wrote:
Charley,

I would like = that!

Jeff

Sent from my = iPad

On Jan 26, 2013, at 1:07 AM, Charles Brown <browncc1@verizon.net> = wrote:

I have = Hartzell's efficiency analysis for their 3-blade and 2-blade props for = the Legacy / IO550, if anyone's interested.  (I suspect that they = would apply equally to any airframe and engine = combination).


On Jan 25, 2013, at 1:32 = PM, Bill Bradburry wrote:

Fred,

I have never been great at reading = graphs, but the diagonal line is airspeed, not HP corrected for prop = efficiency.  That is the vertical line. Or am I wrong??

How do you do this if you have an alternative engine and have no idea of what your HP is?  It seems = that you are guessing about the prop efficiency and I would have to do the same for = HP.  Perhaps if someone gets a FP drag number for the Lancair Legacy FG, I could work backwards and find the HP?

Bill =



= --Apple-Mail=_45DB0471-C15C-44A0-973A-05E7DD81A7EA--