Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Sun, 16 Jan 2005 21:15:02 -0500 Message-ID: X-Original-Return-Path: Received: from HQEMGATE03.nvidia.com ([216.228.112.143] verified) by logan.com (CommuniGate Pro SMTP 4.2.8) with ESMTP id 609586 for lml@lancaironline.net; Sun, 16 Jan 2005 20:55:25 -0500 Received-SPF: neutral receiver=logan.com; client-ip=216.228.112.143; envelope-from=colyncase@earthlink.net Received: from hqemfe02.nvidia.com (Not Verified[172.16.227.92]) by HQEMGATE03.nvidia.com id ; Sun, 16 Jan 2005 17:54:32 -0800 Received: from hqemfe03.nvidia.com ([172.16.227.123]) by hqemfe02.nvidia.com with Microsoft SMTPSVC(6.0.3790.211); Sun, 16 Jan 2005 17:54:55 -0800 Received: from thelma.nvidia.com ([172.16.228.84]) by hqemfe03.nvidia.com with Microsoft SMTPSVC(6.0.3790.211); Sun, 16 Jan 2005 17:54:55 -0800 Received: from ccaselt (cvpn-16-111.nvidia.com [10.2.16.111]) by thelma.nvidia.com (8.8.8+Sun/8.8.8) with SMTP id RAA02650 for ; Sun, 16 Jan 2005 17:54:51 -0800 (PST) X-Original-Message-ID: <017e01c4fc37$8a3a8bb0$d410020a@nvidia.com> From: "colyncase on earthlink" X-Original-To: References: Subject: Re: Approved Weights for Lancair IVP/IVPTs X-Original-Date: Sun, 16 Jan 2005 17:54:49 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_017B_01C4FBF4.79183C80" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1437 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 X-Original-Return-Path: colyncase@earthlink.net X-OriginalArrivalTime: 17 Jan 2005 01:54:55.0266 (UTC) FILETIME=[8AA49820:01C4FC37] This is a multi-part message in MIME format. ------=_NextPart_000_017B_01C4FBF4.79183C80 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable included in the post below is reference to Dave Morss's LA to Lakeland 6 = hour record. I assume he didn't land with empty tanks? Anyone know how much gas he = had? (this is pertinent to the thread). I don't know what the tailwind was that day but workiing backwards it = looks like he had to have more than 140 gals ----- Original Message -----=20 From: Brent Regan=20 Sent: Friday, January 14, 2005 5:14 PM Subject: Re: Approved Weights for Lancair IVP/IVPTs My thanks to Roberto d'Enginero for providing the calculations that = substantiate the points that I was trying to make in my previous post, = those being: 1) You can load an aircraft well past its listed gross weight and it = will still fly. 2) The more weight you add the less safe the situation. 3) You cannot fly an airplane with a stall speed greater than its = maneuvering speed Va. Whether the ultimate gross weight is 18,000 or 28,500 pounds is = irrelevant to the point. In the spirit of Bob's post I should point out = that Bob is using the wing lift and the gross weight interchangeably. = This is not correct (I'll take those quarters back). Using the 18,000 = pound number as the ultimate gross weight is, by design, calculated to = be conservative. As Bob pointed out, the load carried IN the wings = (including the wing structure) is not factored . Also not considered is = the lift generated by the fuselage, the vertical component of the = propeller thrust at high alpha and the effect of temperature on the = composite structure. Bob's assertion that the wings will clap at 18,000 = pounds gross is very probably inaccurate and would require empirical = determination. Perhaps Roberto d'Testpilot would volunteer. Bob writes " Brent continues with the mythical 200% (8.8G) ultimate = load factor, which doesn't exist and never has!" Ouch, this one is gonna hurt. I would direct you to the Lancair = published flyer circa 1992 attached. Next to G Loading (ultimate) you = will see the "mythical" +8.8. Also note the 2,900 pound gross weight and = 82 gallons of fuel. Bob also writes "My apologies to the persons named, it's not the = purpose of my posting to embarrass anyone." Not to worry, I am offended = by people with malicious intent , not by ones who are well meaning but = misinformed. I suspect the only one you have embarrassed is yourself. People who live in false premiss(es) shouldn't throw conclusions. My theory is this. The original IV was designed with a 2,900 lb gross = and a 2.0 to 1 safety factor. A IV wing weighs about 180 Lbs all up or = 360 Lbs the pair and both will carry 492 Lbs of fuel (original 82 = gallons) for a total of 852 pounds of wing and fuel and the balance of = 2048 pounds in the fuselage. It is the fuselage that is trying snap off = the wings so if you reduce the factor of safety to ultimate failure from = 2.0 to 1.5 (Part 23.303 spam can margins) you get a new fuselage weight = of 2731 lbs. Add back the wing weight and you get 3583 Lbs gross = weight. Interesting close to the 3550 now published.=20 The increase in gross weight from 2,900 lbs to 3,550 lbs has come at = the cost of a reduction in the factor of safety from ~2.0 to ~1.5. and = an increase in stall speeds. Lancair DID do an empirical wing strength test, back when the earth = was still cooling, and as I recall (and I am probably wrong) the wing = failed at ~11 Gs. This would correspond to a fuselage weight of 22,528 = and a gross weight of 23,380 lbs. Factor in fuselage lift and vertical = thrust component and 28,500 isn't so far off the mark. However, a test = IS the best way to know for sure so, Roberto, if you want your quarter, = do the test and send me the results. If the wings come off at 23,250 Lbs = (half way between our numbers) take off weight, you win.=20 Is a gross weight of 3,550 Lbs safe? Safety is relative and if you = load your plane more than the situation will allow your relatives will = find out. Regards Brent Regan -------------------------------------------------------------------------= ----- ------=_NextPart_000_017B_01C4FBF4.79183C80 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
included in the post below is reference = to Dave=20 Morss's LA to Lakeland 6 hour record.
 
I assume he didn't land with empty = tanks? =20 Anyone know how much gas he had?
(this is pertinent to the = thread).
I don't know what the tailwind was that = day but=20 workiing backwards it looks like he had to have more than 140 = gals
----- Original Message -----
From:=20 Brent=20 Regan
Sent: Friday, January 14, 2005 = 5:14=20 PM
Subject: Re: Approved Weights = for Lancair=20 IVP/IVPTs

My thanks to Roberto d'Enginero for = providing=20 the calculations that substantiate the points that I was trying to = make in my=20 previous post, those being:

1)  You can load an aircraft = well past=20 its listed gross weight and it will still fly.
2) The more weight = you add=20 the less safe the situation.
3) You cannot fly an airplane with a = stall=20 speed greater than its maneuvering speed Va.

Whether the = ultimate gross=20 weight is 18,000 or 28,500 pounds is irrelevant to the point. In the = spirit of=20 Bob's post I should point out that Bob is using the wing lift and the = gross=20 weight interchangeably. This is not correct (I'll take those quarters = back).=20 Using the 18,000 pound number as the ultimate gross weight is, by = design,=20 calculated to be conservative. As Bob pointed out, the load carried IN = the=20 wings (including the wing structure) is not factored . Also not = considered is=20 the lift generated by the fuselage, the vertical component of the = propeller=20 thrust at high alpha and the effect of temperature on the composite=20 structure.  Bob's assertion that the wings will clap at 18,000 = pounds=20 gross is very probably inaccurate and would require empirical = determination.=20 Perhaps Roberto d'Testpilot would volunteer.

Bob writes "=20
Brent continues with the = mythical=20 200% (8.8G) ultimate load factor, which doesn't exist and never=20 has!"

Ouch, this one is gonna hurt. I would direct you to the = Lancair=20 published flyer circa 1992 attached.  Next to G Loading = (ultimate) you=20 will see the "mythical" +8.8. Also note the 2,900 pound gross weight = and 82=20 gallons of fuel.

Bob also writes "
My apologies to the persons named, it's not the purpose = of my=20 posting to embarrass anyone."  Not to worry, I am offended by = people with=20 malicious intent , not by ones who are well meaning but misinformed. I = suspect=20 the only one you have embarrassed is yourself.

People who live = in false=20 premiss(es) shouldn't throw conclusions.

My theory is = this. The=20 original IV was designed with a 2,900 lb gross and a 2.0 to 1 safety=20 factor.  A IV wing weighs about 180 Lbs all up or 360 Lbs the = pair and=20 both will carry 492 Lbs of fuel (original 82 gallons) for a total of = 852=20 pounds of wing and fuel and the balance of 2048 pounds in the = fuselage. It is=20 the fuselage that is trying snap off the wings so if you reduce the = factor of=20 safety to ultimate failure from 2.0 to 1.5 (Part 23.303 spam can = margins) you=20 get a new fuselage weight of 2731 lbs. Add back the wing weight and = you=20 get  3583 Lbs gross weight. Interesting close to the 3550 now = published.=20

The increase in gross weight from 2,900 lbs to 3,550 lbs has = come at=20 the cost of a reduction in the factor  of safety from ~2.0 to = ~1.5. and=20 an increase in stall speeds.

Lancair DID do an empirical wing = strength=20 test, back when the earth was still cooling, and as I recall (and I am = probably wrong) the wing failed at ~11 Gs.  This would correspond = to a=20 fuselage weight of 22,528 and a gross weight of  23,380 lbs. = Factor in=20 fuselage lift and vertical thrust component and 28,500 isn't so far = off the=20 mark. However, a test IS the best way to know for sure so, Roberto, if = you=20 want your quarter, do the test and send me the results. If the wings = come off=20 at 23,250 Lbs (half way between our numbers) take off weight, you win. =

Is a gross weight of 3,550 Lbs safe? Safety is relative and if = you=20 load your plane more than the situation will allow your relatives will = find=20 out.

Regards
Brent Regan


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