X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 15 Aug 2007 18:47:17 -0400 Message-ID: X-Original-Return-Path: Received: from elasmtp-mealy.atl.sa.earthlink.net ([209.86.89.69] verified) by logan.com (CommuniGate Pro SMTP 5.1.11) with ESMTP id 2264164 for lml@lancaironline.net; Wed, 15 Aug 2007 10:58:19 -0400 Received-SPF: none receiver=logan.com; client-ip=209.86.89.69; envelope-from=rtitsworth@mindspring.com DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=mindspring.com; b=IoHfkJRNTIN0eU8nSaKkmC1Q8AiBuZWOVIrOKNOIxWFHZvaS3bv8yAsG3Qcdiztj; h=Received:From:To:Subject:Date:Message-ID:MIME-Version:Content-Type:X-Mailer:In-Reply-To:Thread-Index:X-MimeOLE:X-ELNK-Trace:X-Originating-IP; Received: from [71.238.59.21] (helo=RDTVAIO) by elasmtp-mealy.atl.sa.earthlink.net with asmtp (Exim 4.34) id 1ILKJa-0006TQ-CN for lml@lancaironline.net; Wed, 15 Aug 2007 10:57:42 -0400 From: "rtitsworth" X-Original-To: "'Lancair Mailing List'" Subject: RE: [LML] Apologies to the farmer's daughter X-Original-Date: Wed, 15 Aug 2007 10:57:23 -0400 X-Original-Message-ID: <003601c7df4c$97b97210$6400a8c0@RDTVAIO> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0037_01C7DF2B.10A7D210" X-Mailer: Microsoft Office Outlook 11 In-Reply-To: Thread-Index: AcffP6eI71JjkbxtQBOE4trbCcIsdAAC56Kw X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 X-ELNK-Trace: b17f11247b2ac8f0a79dc4b33984cbaa0a9da525759e2654fcda7fb03b2ca095b69249e6a419fbf2b07bc47b65cfebd7350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 71.238.59.21 This is a multi-part message in MIME format. ------=_NextPart_000_0037_01C7DF2B.10A7D210 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Rob, etal, FYI: 25fps ~= 17 mph. About like running (full sprint) into solid wall. Perhaps survivable, by OUCH. More math. Gravitational acceleration is approx 32ft/sec^2 (drag-less freefall at the Earth's surface) Doing some algebra to solve for the time to reach 25 fps results in: (25/32)^.5 = 0.88 seconds Doing some integral calculus (not shown) results in a distance traveled of approx 7.5 feet Thus, 25 f/s is about the impact speed from falling off the top step of an 8' step ladder Be careful when cleaning your gutters out there :-) Or another analogy (in case you haven;t fallen off the top of a 8' step ladder lately), terminal velocity from the top of a 34" bar stool would be approximately 12.5 fps (note: 1/2 speed = 1/4 of the impact energy). Rick _____ From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of rwolf99@aol.com Sent: Wednesday, August 15, 2007 9:25 AM To: lml@lancaironline.net Subject: [LML] Apologies to the farmer's daughter Guys -- Richard Titsworth pointed out to me that the 25 foot-per-second descent rate with a BRS *is* 1500 feet per minute. Gee, I get the "turkey of the day" award... Anyway, they claim that 25 fps (1500 fpm) is survivable. They told us that they want the airplane to land slightly nose down. If we were going to land tail first, they would have insisted on head-rest-type protection features. You know, 25 fps didn't sound all that fast to me, but 1500 fpm seems pretty darn fast to be crunching into the ground. - Rob Wolf _____ AOL now offers free email to everyone. Find out more about what's free from AOL at AOL.com. ------=_NextPart_000_0037_01C7DF2B.10A7D210 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Rob, = etal,

FYI: 25fps ~=3D 17 mph. About like running (full sprint) into solid = wall. Perhaps survivable, by OUCH.

More = math…

Gravitational acceleration is = approx 32ft/sec^2 (drag-less freefall at the Earth’s = surface)

Doing some algebra to solve for the = time to reach 25 fps results in: (25/32)^.5 =3D 0.88 seconds

Doing some integral calculus (not = shown) results in a distance traveled of approx 7.5 = feet

Thus, 25 f/s is about the impact = speed from falling off the top step of an 8’ step = ladder

Be careful when cleaning your = gutters out there J

Or another analogy (in case you = haven;t fallen off the top of a 8’ step ladder lately), terminal velocity = from the top of a 34” bar stool would be approximately 12.5 fps = (note: 1/2 speed =3D 1/4 of the impact = energy).

Rick

From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of = rwolf99@aol.com
Sent: Wednesday, August 15, 2007 9:25 AM
To: lml@lancaironline.net
Subject: [LML] Apologies to the farmer's daughter

Guys --

Richard Titsworth pointed out to me that the 25 foot-per-second descent = rate with a BRS *is* 1500 feet per minute. Gee, I get the = "turkey of the day" award...

Anyway, they claim that 25 fps (1500 fpm) is survivable. They told = us that they want the airplane to land slightly nose down. If we were = going to land tail first, they would have insisted on head-rest-type = protection features.

You know, 25 fps didn't sound all that fast to me, but 1500 fpm seems = pretty darn fast to be crunching into the ground.

- Rob Wolf

AOL now offers free email to everyone. Find = out more about what's free from AOL at AOL.com.

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