Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Tue, 11 Jan 2005 22:26:38 -0500 Message-ID: X-Original-Return-Path: Received: from out005.verizon.net ([206.46.170.143] verified) by logan.com (CommuniGate Pro SMTP 4.2.8) with ESMTP id 603534 for lml@lancaironline.net; Tue, 11 Jan 2005 12:42:21 -0500 Received-SPF: pass receiver=logan.com; client-ip=206.46.170.143; envelope-from=c.larue@verizon.net Received: from MediaCenter ([65.238.14.213]) by out005.verizon.net (InterMail vM.5.01.06.06 201-253-122-130-106-20030910) with ESMTP id <20050111174149.XOXO28362.out005.verizon.net@MediaCenter> for ; Tue, 11 Jan 2005 11:41:49 -0600 From: "Carl La Rue" X-Original-To: "Lancair Mailing List" Subject: GROSS WEIGHTS X-Original-Date: Tue, 11 Jan 2005 12:41:33 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0046_01C4F7DA.E42026A0" X-Mailer: Microsoft Office Outlook, Build 11.0.6353 Thread-Index: AcT4BMpV0G7VQ5h5TXOsxd2xWCbJwQ== X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Authentication-Info: Submitted using SMTP AUTH at out005.verizon.net from [65.238.14.213] at Tue, 11 Jan 2005 11:41:40 -0600 X-Original-Message-Id: <20050111174149.XOXO28362.out005.verizon.net@MediaCenter> This is a multi-part message in MIME format. ------=_NextPart_000_0046_01C4F7DA.E42026A0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Colyn, You asked a legitimate question about "feel" at weights above 3200 lbs. and haven't had a direct answer. I think I know why; it's hard to answer. I've flown my 3200# IVP to 3300, 3400 and 3500 in controlled conditions, on purpose, so I would know my airplane's capabilities better, for the same reason I've practiced slow flight in the burble and now know exactly when to unload to catch the snap roll just as it starts (and yes, I've been late and had to recover from vertical, and tried it again, and again. Now I believe.) To me, it's a progressive feeling of discomfort as I exceed 3200#. My CG is always within limits, albeit moving aft as the weight increases, but the airplane becomes progressively more "sensitive" (unstable?) in pitch. It is mostly noticeable immediately after takeoff where the pitch inputs needed become relatively exaggerated to correct a slight tendency towards pitch porpoising. (I don't have winglets and others may have a different feel than mine.) Higher gross also (obviously) leads to a longer T/O roll, slower acceleration to climb speed and a decreased climb rate. The airplane can handle it, and has, but all the training and experience that I have garnered in 50 years of challenging flying has sensitized me to those first moments of flying after takeoff to initial climb speed with the airplane cleaned up and able to maneuver to an off-airport parking place. Gross weights that cut my margin make me squirm. Let me help you rethink your needs. My aircraft has an empty weight of 2235 lbs. Yours may be more or less. I have the original 80 gallon fuel capacity and no winglets. Full fuel, two FAA occupants and 100 lbs of baggage puts us at 3165 lbs. The airplane flies great. It's three easy legs to Santa Barbara from eastern Ohio and two legs back. Extended fuel became an option after I had closed my wings and I would have added it but LOP operation, which I learned from George B. in the Cayman Islands 5 or 6 years ago, made up for the gas that I now don't have to carry. My guess is that you will also become uncomfortable at the higher gross weights or simply have no reason to operate there and, regardless of what your DAR will "give" you, most of your flights will be like mine. Brent comes at this question from a hard-nosed engineering perspective. Brent should be taken seriously, as should Charlie K. I'm not an engineer, or a DAR, but I have had to fly at the edge of the performance envelope, and test it, in the past. In that context, I think that I would not have any fun flying the IVP at 3500 lbs or above on a routine basis because it would make me squirm, adding stress which reduces fun, etc. Whatever weight you certify your plane for, Colyn, you have now had serious input, as has Jeff L., the original questioner. Thanks for asking; you are now less likely to affect our insurance rates. Carl La Rue ------=_NextPart_000_0046_01C4F7DA.E42026A0 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Colyn,

 

You asked a legitimate question about = “feel” at weights above 3200 lbs. and haven’t had a direct answer.  I = think I know why; it’s hard to answer.  I’ve flown my 3200# IVP = to 3300, 3400 and 3500 in controlled conditions, on purpose, so I would = know my airplane’s capabilities better, for the same reason I’ve = practiced slow flight in the burble and now know exactly when to unload to catch the = snap roll just as it starts (and yes, I’ve been late and had to recover from = vertical, and tried it again, and again.  Now I = believe.)

 

To me, it’s a progressive feeling of discomfort = as I exceed 3200#.  My CG is always within limits, albeit moving aft as = the weight increases, but the airplane becomes progressively more = “sensitive” (unstable?) in pitch.  It is mostly noticeable immediately after = takeoff where the pitch inputs needed become relatively exaggerated to correct a = slight tendency towards pitch porpoising. (I don’t have winglets and = others may have a different feel than mine.)  Higher gross also (obviously) = leads to a longer T/O roll, slower acceleration to climb speed and a decreased = climb rate.  The airplane can handle it, and has, but all the training = and experience that I have garnered in 50 years of challenging flying has = sensitized me to those first moments of flying after takeoff to initial climb speed = with the airplane cleaned up and able to maneuver to an off-airport parking = place.  Gross weights that cut my margin make me squirm.

 

Let me help you rethink your needs.  My aircraft = has an empty weight of 2235 lbs.  Yours may be more or less.  I have = the original 80 gallon fuel capacity and no winglets.  Full fuel, two = FAA occupants and 100 lbs of baggage puts us at 3165 lbs.  The airplane flies great.  It’s three easy legs to Santa = Barbara from eastern Ohio and two legs back.  Extended fuel became an option after I had = closed my wings and I would have added it but LOP operation, which I learned from = George B. in the Cayman Islands 5 or 6 years ago, made up for the gas that I = now don’t have to carry.  My guess is that you will also become uncomfortable = at the higher gross weights or simply have no reason to operate there and, = regardless of what your DAR will “give” you, most of your flights will = be like mine. 

 

Brent comes at this question from a hard-nosed = engineering perspective. Brent should be taken seriously, as should Charlie K.  =

I’m not an engineer, or a DAR, but I have had = to fly at the edge of the performance envelope, and test it, in the past.  = In that context, I think that I would not have any fun flying the IVP at = 3500 lbs or above on a routine basis because it would make me squirm, adding = stress which reduces fun, etc.

 

Whatever weight you certify your plane for, Colyn, = you have now had serious input, as has Jeff L., the original questioner. =  Thanks for asking; you are now less likely to affect our insurance = rates.

 

Carl La Rue =    

 

 

 

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