Return-Path: Sender: (Marvin Kaye) To: lml@lancaironline.net Date: Mon, 22 Sep 2003 14:34:13 -0400 Message-ID: X-Original-Return-Path: Received: from mail-7.tiscali.it ([195.130.225.153] verified) by logan.com (CommuniGate Pro SMTP 4.1.3) with ESMTP id 2589433 for lml@lancaironline.net; Mon, 22 Sep 2003 14:03:15 -0400 Received: from trottolino (62.11.1.27) by mail-7.tiscali.it (6.7.019) id 3F60985500738B9B for lml@lancaironline.net; Mon, 22 Sep 2003 20:03:13 +0200 X-Original-Message-ID: <007301c38134$53e05880$1b010b3e@interbusiness.it> From: "Robert Overmars" X-Original-To: "Lancair Mailing List" Subject: The LIV wing... X-Original-Date: Mon, 22 Sep 2003 20:07:01 +0200 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0070_01C38145.15AD20A0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 This is a multi-part message in MIME format. ------=_NextPart_000_0070_01C38145.15AD20A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Salutti tutti, The next time when flying your LIV during a quiet moment take a moment = and spare a thought for that wing out there that keeps you aloft. It's = an amazing piece of design and construction but it works soooh well = manipulating air pressures and flows that it keeps the increasingly = obese LIV aloft almost effortlessly. (For comparasion here in Italy is a = company building a new Frati design four seat aeroplane with a max gross = weight of around 2,900 -3,000lbs. The chord of their wing is 50% greater = than the LIV wing, the wing span longer by about 3 feet and their design = studies indicate they will have trouble meeting the required 61 knots = stall speed for a certified aeroplane) So getting back to our moment of = TM in the cockpit of the LIV contemplating the LIV wing just how much = wing is actually out there in the breeze? ....and the answer is not as = much as you think. Between BL 25.5 and BL171 is 38.87 square feet of = wing. Add a square foot or so for the wingtip and we'll call it a nice = round 40 sq ft per wing. (If you have winglets add at a guess 5 square = feet to total a nice round 44 square feet) But you say I purchased 98 square feet of wing from Lancair! So what or = where is the difference and the answer is "you are sitting on it". By = design convention the wing planform that 'passes' through the fuselage = is included in the total wing area and if we include this area we come = upto the 98 square you purchased from Lancair. It seems to me as the = fuselage is nicely placed between BL25.5 port and stbd we are = effectively loosing wing area and consequently lift, but some of this = lift is undoubtedly replaced by fuselage lift but by how much I don't = know. Maybe designers deliberately use only calculated wing area to keep = everything simple. If you know more do let me know. Back now to our moment of cockpit TM, we turn our focus to how the = fuselage weight and g loads are carried by the wing. Under our seats are = two 3/4" bolts which bolt the wing spars to the shear box...plenty = strong there. Look now at the couple of bits of prepreg and 6 bid layups = that attach the shear box to the fuselage sides and how strong are = these?? Ever been tested to the load limit of 9,250 lbs each side? = which is the ultimate load that the wing can exert on these parts before = the wing fails. My eyeball engineering suggests not but in the designer = I must put my faith, I hope he's correct...but being the sceptic that I = am I'd still love to see it tested. Incidentally fellow amateur aeroplane engineers, regarding wing g loads, = stall speeds and fuselage loads there may be a factor we've not = considered yet Put the brain into gear and see if you can work out what = it is. It's a factor that in straight and level flight is small and is = usually disregarded but with a high pitch rate it can become quite = large, surprisingly large...I think. Ciao, Roberto d'Italia. psst.....tired of humdrum Lancair speeds?? Wanna go fast...really fast?? = Yesterday travelling around Rome came across a place selling second hand = machinery with 8 F-104 Starfighters out the front presumably for sale. = Will go there to have a proper look one day when the place is open to = find out more.=20 =20 ------=_NextPart_000_0070_01C38145.15AD20A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Salutti tutti,
 
The next time when flying your LIV = during a quiet=20 moment take a moment and spare a thought for that wing out there that = keeps you=20 aloft. It's an amazing piece of design and construction but it = works soooh=20 well manipulating air pressures and flows that it keeps the increasingly = obese=20 LIV aloft almost effortlessly. (For comparasion here in Italy = is a=20 company building a new Frati design four seat aeroplane with a max = gross=20 weight of around 2,900 -3,000lbs. The chord of their wing is 50% greater = than=20 the LIV wing, the wing span longer by about 3 feet and their design = studies=20 indicate they will have trouble meeting the required 61 knots stall = speed for a=20 certified aeroplane)  So getting back to our moment = of TM in=20 the cockpit of the LIV contemplating the LIV wing just how much wing is = actually=20 out there in the breeze? ....and the answer is not as much as you = think.=20 Between BL 25.5 and BL171 is 38.87 square feet of wing. Add a square = foot or so=20 for the wingtip and we'll call it a nice round 40 sq ft per wing. (If = you have=20 winglets add at a guess 5 square feet to total a nice round 44 square=20 feet)
 
But you say I purchased 98 square feet = of wing from=20 Lancair!  So what or where is the difference and the answer is = "you=20 are sitting on it". By design convention the wing planform that 'passes' = through=20 the fuselage is included in the total wing area and if we include this = area we=20 come upto the 98 square you purchased from Lancair. It seems to = me as=20 the fuselage is nicely placed between BL25.5 port and stbd we are=20 effectively loosing wing area and consequently lift, but some = of this=20 lift is undoubtedly replaced by fuselage lift but by how much I = don't know.=20 Maybe designers deliberately use only calculated wing area to keep=20 everything simple. If you know more do let me know.
 
Back now to our moment of cockpit TM, = we turn our=20 focus to how the fuselage weight and g loads are carried by the wing. = Under our=20 seats are two 3/4" bolts which bolt the wing spars to the shear = box...plenty=20 strong there. Look now at the couple of bits of prepreg and 6 bid layups = that=20 attach the shear box to the fuselage sides and how strong are these?? = Ever been=20 tested to the load limit of 9,250 lbs each side?  which is=20 the ultimate load that the wing can exert on these parts before the = wing=20 fails. My eyeball engineering suggests not but in the designer I must = put my=20 faith, I hope he's correct...but being the sceptic that I am I'd still = love to=20 see it tested.
 
Incidentally fellow amateur aeroplane=20 engineers, regarding wing g loads, stall speeds and fuselage=20 loads there may be a factor we've not considered yet  Put = the=20 brain into gear and see if you can work out what it is. It's a factor = that in=20 straight and level flight is small and is usually disregarded but with=20 a high pitch rate it can become quite large, surprisingly large...I = think.
 
Ciao,
 
Roberto d'Italia.
 
psst.....tired of humdrum Lancair = speeds?? Wanna go=20 fast...really fast?? Yesterday travelling around Rome came across a = place=20 selling second hand machinery with 8 F-104 Starfighters out the front = presumably=20 for sale. Will go there to have a proper look one day when the = place is=20 open to find out more. 
 
 
 
   
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