Return-Path: Sender: (Marvin Kaye) To: lml Date: Fri, 17 Jan 2003 07:58:43 -0500 Message-ID: X-Original-Return-Path: Received: from [64.4.8.118] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.0.5) with ESMTP id 1990928 for lml@lancaironline.net; Thu, 16 Jan 2003 22:14:28 -0500 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Thu, 16 Jan 2003 19:14:28 -0800 X-Originating-IP: [67.1.57.166] From: "Gary Edwards" X-Original-To: "LML" Subject: Wing Loading mysteries X-Original-Date: Thu, 16 Jan 2003 19:13:55 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_005B_01C2BD93.6A11F880" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN Mail 8.00.0022.3100 X-MimeOLE: Produced By Microsoft MimeOLE V8.00.0022.3100 X-Original-Message-ID: X-OriginalArrivalTime: 17 Jan 2003 03:14:28.0114 (UTC) FILETIME=[8B842720:01C2BDD6] This is a multi-part message in MIME format. ------=_NextPart_000_005B_01C2BD93.6A11F880 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Here is some additional clarification regarding 235 airframes. The flap reflex amount is -8 degrees (not -7 degrees as stated on the = LML) as per the builders manual page 236, figure 228. The down flap = amount is +23 degrees (not +25 degrees as stated on the LML), same = manual page and figure. So really there is a total of 32 degrees = available..in the hanger. (more on that later) The +23 degrees down flap maximum amount (+ or - a little for different = builders) was because of the lower flap rolled leading edge being in = conflict with the rear spar at full down travel. Hence the reason for = the change from upper skin hinge to lower skin hinge on the 320/360 = models so as to get 30 or 40 degrees. As Earl has done, some 235 = builders built lower hinged flaps. My compliments to Earl and others as = it is a lot of extra work. The +23 degrees is most likely only attainable on the ground. In = flight, in the pattern, it is likely only about +19 degrees. This is as = a result of up pressure in flight pushing on the flap system "slop" and = overall flexing of the flaps. I see this situation on every flight with = my digital flap indicator. As does Earl and others, I cruise fly with about -4 degrees reflex ( 3/4 = inch up from neutral) as Don G. had suggested. Less twist (strain) in = the wing as I was told. Also other 235ers have indicated, some on the = LML, that their best cruise speeds are with this partial up reflex.=20 The 235 and 320 tails are NOT exactly the same. The 235 vertical stab. = and rudder are smaller than the 320/360. As a result, they are marginal = on takeoff with a 320 up front. Hence the reason several builders opted = to build the ventral fin on the bottom of the fuselage and add the same = amount to the bottom of the rudder as Earl did. It adds about 15% more = rudder area. It also helps take some of the wiggle out of the tail in = flight. (shorter fuselage length on 235 than 320/360) The 235 horiz. = stab., although the same physical size, does not have an interior front = spar like the 320/360 unless the builders chose to install them as I and = others did. Also, as JJ indicated, there is an additional rib in the = tail cone on the 320/360 that is not in the 235. The wings on the 235 are the same as the 320/360 except for the tips. = The fuel capacity was increased in the 320/360 for obvious reasons; = bigger engine =3D higher fuel burn. 33 gallons in the 235 wasn't enough = for 320/360 engines. As others stated, more fuel capacity was added. Now we get to the good part; gross weight. Lancair raised the gross weight on 235's from: 1400#=20 to: 1500# on = take off, 1400# on landing. =20 So let's look at an example. 235 aircraft weight with 320 engine: 1025# (+ some with an = electric prop?) 33 gallons of fuel (standard construction): 198# (some builders have = >50 gallons, so + 102# more?) Pilot/passenger: 360# (I wish) Baggage (for 2) 35# (I wish) Total 1618# So, WITHOUT fuel, the 235 above is 20# over gross on landing. Add the = fuel and extras and the gross is over 1700#. (makes for interesting = approaches and landings with a fixed pitched prop) As Scott mentioned, that is why they are called "experiMENTAL". Each = builder can set their own gross weight based on their own comfort (risk) = level and possible ramp check level. =20 Now before I go for a ride in your plane, first let me ask you about = your...... Gary Edwards LNC2 N21SN =20 ------=_NextPart_000_005B_01C2BD93.6A11F880 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Here is some additional clarification regarding 235 = airframes.
 
The flap reflex amount is -8 degrees (not -7 degrees as stated on = the LML)=20 as per the builders manual page 236, figure 228.  The down flap = amount is=20 +23 degrees (not +25 degrees as stated on the LML), same manual page and = figure.=20 So really there is a total of 32 degrees available=85.in the = hanger. (more on=20 that later)
 
The +23 degrees down flap maximum amount (+ or - a little for = different=20 builders) was because of the lower flap rolled leading edge being in = conflict=20 with the rear spar at full down travel.  Hence the reason for the = change=20 from upper skin hinge to lower skin hinge on the 320/360 models so as to = get 30=20 or 40 degrees.  As Earl has done, some 235 builders built lower = hinged=20 flaps.  My compliments to Earl and others as it is a lot of extra=20 work.
 
The +23 degrees is most likely only attainable on the = ground.  In=20 flight, in the pattern, it is likely only about +19=20 degrees.  This is as a result of up pressure in flight pushing = on the=20 flap system "slop" and overall flexing of the flaps.  I see = this=20 situation on every flight with my digital flap indicator.
 
As does Earl and others, I cruise fly with about = -4 degrees=20 reflex ( 3/4 inch up from neutral) as Don G. had suggested.  Less = twist=20 (strain) in the wing as I was told.  Also other 235ers have = indicated, some=20 on the LML, that their best cruise speeds are with this partial up=20 reflex. 
 
The 235 and 320 tails are NOT exactly the same.  The = 235=20 vertical  stab. and rudder are smaller than the 320/360.  = As a=20 result, they are marginal on takeoff with a 320 up front.  Hence = the reason=20 several builders opted to build the ventral fin on the bottom of = the=20 fuselage and add the same amount to the bottom of the rudder as Earl = did. =20 It adds about 15% more rudder area.  It also helps take some of the = wiggle=20 out of the tail in flight. (shorter fuselage length on 235 than = 320/360) =20 The 235 horiz. stab., although the same physical size, does not = have an=20 interior front spar like the 320/360 unless the builders chose to = install them=20 as I and others did.  Also, as JJ indicated, there is an additional = rib in=20 the tail cone on the 320/360 that is not in the 235.
 
The wings on the 235 are the same as the 320/360 except for the = tips. =20 The fuel capacity was increased in the 320/360 for obvious reasons; = bigger=20 engine =3D higher fuel burn.  33 gallons in the 235 wasn't = enough for=20 320/360 engines.  As others stated, more fuel capacity was = added.
 
Now we get to the good part; gross weight.
 
Lancair raised the gross weight on 235's from: 1400# 
           &n= bsp;           &nb= sp;           &nbs= p;            = ;         to: 1500#=20 on take off, 1400# on landing. 
So let's look at an example.
 
235 aircraft weight with 320=20 engine:         1025# (+ some = with an=20 electric prop?)
33 gallons of fuel (standard construction):  198# (some = builders have=20 >50 gallons, so + 102# more?)
Pilot/passenger:        &nbs= p;            = ;            =    =20 360# (I wish)
Baggage (for=20 2)            = ;            =             &= nbsp; =20 35# (I wish)
 
Total          &nb= sp;           &nbs= p;            = ;            =    =20 1618#
 
So, WITHOUT fuel, the 235 above is 20# over gross on landing.  = Add the=20 fuel and extras and the gross is over 1700#. (makes for interesting = approaches and landings with a fixed pitched prop)
 
As Scott mentioned, that is why they are called = "experiMENTAL". =20 Each builder can set their own gross weight based on their own=20 comfort (risk) level and possible ramp check level. 
 
Now before I go for a ride in your plane, first let me ask you = about=20 your=85=85=85=85..
 
Gary Edwards
LNC2 N21SN  
 
    
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