X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 02 Sep 2011 07:51:44 -0400 Message-ID: X-Original-Return-Path: Received: from imr-da04.mx.aol.com ([205.188.105.146] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with ESMTP id 5110770 for lml@lancaironline.net; Thu, 01 Sep 2011 13:35:49 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.105.146; envelope-from=Sky2high@aol.com Received: from mtaomg-db04.r1000.mx.aol.com (mtaomg-db04.r1000.mx.aol.com [172.29.51.202]) by imr-da04.mx.aol.com (8.14.1/8.14.1) with ESMTP id p81HZ4kU013394 for ; Thu, 1 Sep 2011 13:35:04 -0400 Received: from core-mte004c.r1000.mail.aol.com (core-mte004.r1000.mail.aol.com [172.29.236.77]) by mtaomg-db04.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id 54C47E000082 for ; Thu, 1 Sep 2011 13:35:03 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: <13d4e.49d928f4.3b911c47@aol.com> X-Original-Date: Thu, 1 Sep 2011 13:35:03 -0400 (EDT) Subject: Re: [LML] Sir Isaac Re: LIV Shoulder Harness X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_13d4e.49d928f4.3b911c47_boundary" X-Mailer: AOL 9.6 sub 168 X-Originating-IP: [24.1.9.48] x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 1:2:433981824:93952408 X-AOL-SCOLL-URL_COUNT: 1 x-aol-sid: 3039ac1d33ca4e5fc2472ef0 --part1_13d4e.49d928f4.3b911c47_boundary Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable No time to figure it out............but, if you wear glasses your eyeballs = =20 won't go too far. =20 Grayhawk =20 =20 In a message dated 9/1/2011 12:28:38 P.M. Central Daylight Time, =20 cwfmd@yahoo.com writes: Okay, it's back to school time again, soooo...... Alert- Spoiler- MathemaPhobes should not read past this point: =20 "Word-Problem" =20 Crash survivalbility is an important consideration, especially given the= =20 high number of G-induced fatalities, in this speedy aircraft. Our main=20 threat here, is brilliantly described by Sir Isaac, 423 years _ago_=20 (http://en.wikipedia.org/wiki/Philosophi=E6_Naturalis_Principia_Mathematica= ) , because=20 the kinetic energy goes up as the square of the velocity. If you are going= 2=20 times as fast, as compared to your FAA certified 62 mph'er, when you hit= =20 the ditch, or barrier at the boundary of your emergency farmer's field, 4= =20 times the forces must be disipated. 10-20 Gs in the X direction (eyeballs = out)=20 is the limit of survivable crash forces. =20 Scenario: On takeoff, I checked all the multi-engine monitors in the=20 green, the FF hit 44 gph as I rotated and all seemed well, even though I= =20 briefed and reminded myself of a very low "abort threshold". If everything= went=20 well in preflight (did I sample both tanks for water, strainer, and=20 operational fuel valve?), taxing, and runup, what are the odds of somethin= g=20 catestrophic happening, in a properly maintained, firewall forward, certif= ied=20 engine? Well today it did it, started sputtering at 850 feet, and quit=20 completely just as I finished lowering the nose for glide, switching tanks= , cycling=20 mags, low boost then high, twidling the knobs.... NADA. Now I've got 450= =20 feet AGL and a nice 1000 foot farmers field 18 degrees to the left. If I j= ust=20 clear the fence, on this end, and get full flaps touchdown at 89 KIAS (std= =20 day). MAGS, master, valve off, land, pop the door? (wait... is the gear up= =20 or down- which is better?) Do you hold it off for a smooth touchdown in=20 ground effect, or plant it like we learned for short runway ops? At 70 KIA= S =3D=20 60 Kt GS =3D 30 meters/ second, how much distance do I need to survive th= is=20 today?=20 =20 Hints: KE=3D 1/2 m v^2 1 G =3D 9.8 meter/sec^2 10 G =3D 98 meter/sec^= 2 =20 Newton: F =3D m a =3D KE/d or KE=3D m a d (mass drops out ! ) =20 Bonus question: What if my choices are water (ditching) vs unfriendly=20 rocky beach vs trees? =20 Remember, the most important crash survivability criterion is prevervation= =20 of the space around the human, properly restrained. Would airbags help? I= =20 don't have enough data. How 'bout 4 -5 point restraint - probably, but is there any data from=20 certification testing on the ES to Columbia to Cessna 400 certification? = hmmm --part1_13d4e.49d928f4.3b911c47_boundary Content-Type: text/html; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable
No time to figure it out............but, if you wear glasses your eyeb= alls=20 won't go too far.
 
Grayhawk
 
In a message dated 9/1/2011 12:28:38 P.M. Central Daylight Time,=20 cwfmd@yahoo.com writes:
=
Okay, it's back to school time again, soooo......
Alert- Spoiler- MathemaPhobes should not read past this=20 point:   "Word-Problem"
 
Crash survivalbility is an important consideration, especially= =20 given the high number of G-induced fatalities, in this speedy aircr= aft.=20 Our main threat here, is brilliantly described by Sir Isaac, 4= 23=20 years ago,=20 because the kinetic energy goes up as the square of the velocity. I= f you=20 are going 2 times as fast, as compared to your FAA certif= ied=20 62 mph'er, when you hit the ditch, or barrier at the boundary = of=20 your emergency farmer's field, 4 times the forces must be disipated= .=20 10-20 Gs in the X direction (eyeballs out) is the limit of survivab= le=20 crash forces.
 
 Scenario: On takeoff, I checked all the multi-engine mon= itors=20 in the green, the FF hit 44 gph as I rotated and all seemed well, e= ven=20 though I briefed and reminded myself of a very low "abort threshold= ". If=20 everything went well in preflight (did I sample both tanks for wate= r,=20 strainer, and operational fuel valve?), taxing, and runup, what are= the=20 odds of something catestrophic happening, in a properly maintained,= =20 firewall forward, certified engine?
  Well today it did it, started sputtering at 850 fe= et,=20 and quit completely just as I finished lowering the nose for glide,= =20 switching tanks, cycling mags, low boost then high, twidling the=20 knobs.... NADA. Now I've got 450 feet AGL and a nice 1000 foot farm= ers=20 field 18 degrees to the left. If I just clear the fence, on this en= d,=20 and get full flaps touchdown at 89 KIAS (std day). MAGS, master,=20 valve off, land, pop the door? (wait... is the gear up or down= -=20 which is better?) Do you hold it off for a smooth touchdown in grou= nd=20 effect, or plant it like we learned for short runway ops? At 70 KIA= S =3D=20 60 Kt GS =3D 30 meters/ second, how much distance do I need to surv= ive=20 this today?
 
Hints:  KE=3D 1/2 m v^2   1 G =3D 9.8=20 meter/sec^2   10 G =3D 98 meter/sec^2
 
Newton:  F =3D m a =3D KE/d    or  KE= =3D m a=20 d   (mass drops out ! )
 
Bonus question: What if my choices are water (ditching) vs=20 unfriendly rocky beach vs trees?
 
Remember, the most important crash survivability criterion is= =20 prevervation of the space around the human, properly restrained. Wo= uld=20 airbags help? I don't have enough data.
How 'bout 4 -5 point restraint - probably, but is there any da= ta=20 from certification testing on the ES to Columbia to Cessna 400=20 certification?  =20 hmmm
--part1_13d4e.49d928f4.3b911c47_boundary--