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ggower_99(at)yahoo.com
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 Posted: Sat Jul 15, 2006 8:44 pm Post subject: Back in the saddle Seat Belt Attachments. |
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Jon,
We all are really GLAD that you are well (in perfect shape very soon, I am shure).
This mail from you is a great lesson for all of us. Thank you very much for your honest and to the point comment. It was close, I know but not your time... Good thing that the airplane got most of the energy and saved you...
Now, about John's comment. Probably the belts could need a little more attachment force.
But lets be honest that the human body can only take certain amount of "G" forces before (fataly and serious) damaging the brain and vital organs... Thats the big diference betwen the modern cars like Volvo and Mercedes (just to mention a pair, not to beguin a discussion) and the 50´s era "strong" Desoto, Chevys and Fords, that they didnt even had seat belts (at least here in Mexico)...
I am sure now that I see Jon's photos that Mr Heintz was thinking in this matter when he designed the 701 cabin area.
I realy hope (and honestly pray) that I (or any one of us in the list) never have a serious accident flying, but I trust blind folded the ZAC airplanes.
Welcome back Jon, If I can be of help, please let me know.
Saludos
Gary Gower.
Flying from Chapala, Mexico.
701 912S
Building a 601 XL, No engine choise yet.
John Bolding <jnbolding1(at)teleshare.net> wrote:
| Quote: | Jon wrote,
| Quote: | the right seat belt attachment came off the center tunnel structure)
I ASSUME (a dangerous thing to do) that everyone will want to chase this rabbit until a solution is offered.
I have always felt that compared to other designs, namely those that I have built or worked on, the restraint hardware on the 701 is on the light side.
PLEASE don't think that I'm trying to second guess Chris here, maybe the attach fitting failed just when and how it was designed (everything has a limit) but I would rather have a harness that stays where it's bolted, keeping me out of the inst panel. I realize there are a host of design considerations here. I also suspect that if there had been a passenger there would have been a lot more load in the center attach area and the POSSIBILITY of failure with less restraint than it offered Jon in this case while solo.
Anyone else having heartburn over this one?
Jon, THANKS for your being so open with your experiences , it's helping us all build and fly better and safer. LOW&SLOW John
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John Bolding
Joined: 23 May 2006
Posts: 281
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| Posted: Sun Jul 16, 2006 5:42 am Post subject: Back in the saddle Seat Belt Attachments. |
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| Quote: |
From: Gary Gower (ggower_99(at)yahoo.com)
Now, about John's comment. Probably the belts could need a little more attachment force.
But lets be honest that the human body can only take certain amount of "G" forces before (fataly and serious) damaging the brain and vital organs...
Gary is correct in stating that there is a limit to what body can take in a harness.
If memory serves, (50% chance of that) ultimate design strength of restraint system on certified aircraft is 40G.
I guess that's with the standard 170# dude so us fat asses can assume less. Or maybe I'm remembering the 40G's is the practical limit of survivalibility. Someone that KNOWS please help me here.
MY point is (and I didn't get it across very well the first time) is that I don't want a 20G system (pick whatever # here you feel is where Jon's system failed) and leave additional protection of my tender pink body on the table. We are saddled with the problem of having rather shallow fuselage depth and seats with a vertical compression component can't be used but that was not the MAIN issue here.
I have aircraft drawings from several well known designers of certified aircraft (in addition to Chris) that have also entered the homebuilt field at one time or another (C.G. Taylor, Dave Thurston, John Thorpe etc.) I'll dig thru them and see if they have a different application of attach fittings.
Some detailed pics of Jon's failure point might help a LOT here.
I have field tested the restraint system of an RV3 using a human (me) and walked away with only a butt that was sore for 6 months, sore neck and SERIOUS bruises from the belts. NOTHING BROKE, no kissing of the panel (it's pretty close on the "3" ), had the restraint system broken Van would have FIXED it!
Whoever said that it's more dangerous to drive to the airport than to fly an airplane was either kidding or doesn't know the facts and is just shooting to hear the gun go off.
LOW&SLOW John
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cleonard52(at)comcast.net
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| Posted: Sun Jul 16, 2006 6:53 am Post subject: Back in the saddle Seat Belt Attachments. |
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ZENITH OFFERS SEAT BELTS THAT HAVE AN AIR BAG ATTACHED. I WOULD THINK THIS WOULD GIVE YOU A LOT OF PROTECTION.
DO NOT ARCHIEVE
CHARLES
| Quote: | -------------- Original message --------------
From: "John Bolding" <jnbolding1(at)teleshare.net>
| Quote: |
From: Gary Gower (ggower_99(at)yahoo.com)
Now, about John's comment. Probably the belts could need a little more attachment force.
But lets be honest that the human body can only take certain amount of "G" forces before (fataly and serious) damaging the brain and vital organs...
Gary is correct in stating that there is a limit to what body can take in a harness.
If memory serves, (50% chance of that) ultimate design strength of restraint system on certified aircraft is 40G.
I guess that's with the standard 170# dude so us fat asses can assume less. Or maybe I'm remembering the 40G's is the practical limit of survivalibility. Someone that KNOWS please help me here.
MY point is (and I didn't get it across very well the first time) is that I don't want a 20G system (pick whatever # here you feel is where Jon's system failed) and leave additional protection of my tender pink body on the table. We are saddled with the problem of having rather shallow fuselage depth and seats with a vertical compression component can't be used but that was not the MAIN issue here.
I have aircraft drawings from several well known designers of certified aircraft (in addition to Chris) that have also entered the homebuilt field at one time or another (C.G. Taylor, Dave Thurston, John Thorpe etc.) I'll dig thru them and see if they have a different application of attach fittings.
Some detailed pics of Jon's failure point might help a LOT here.
I have field tested the restraint system of an RV3 using a human (me) and walked away with only a butt that was sore for 6 months, sore neck and SERIOUS bruises from the belts. NOTHING BROKE, no kissing of the panel (it's pretty close on the "3" ), had the restraint system broken Van would have FIXED it!
Whoever said that it's more dangerous to drive to the airport than to fly an airplane was either kidding or doesn't know the facts and is just shooting to hear the gun go off.
LOW&SLOW John
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cffd(at)pgrb.com
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| Posted: Sun Jul 16, 2006 8:09 am Post subject: Back in the saddle Seat Belt Attachments. |
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When I built my 701, I did not feel comfortable with the aluminum seat belt attachment that was riveted to the tunnel. In fact, somewhere 4 or 5 years ago, on this forum, I read where the bolt between the seat belt and the aluminum attachment pulled a slot through the attachment. So I made my attachment from 0.40" 4031 steel instead of 0.40" 6061 aluminum. I then used the 0.40" 6061 as a doubler on the inside of the tunnel to give more thickness to keep the rivets from pulling through. I did not ask ZAC about this, but I feel that this is a stronger anchor which actually gets pulled by both the lap and shoulder straps.
Jon, you are an inspiration to all of us. Especially, in testing the crash survivability of our aircraft  . Glad to see you are up and around.
Chuck D.
N701TX
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cffd(at)pgrb.com
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| Posted: Sun Jul 16, 2006 8:33 am Post subject: Back in the saddle Seat Belt Attachments. |
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I mean 4130 steel. That was 4 years ago.
[quote] ---
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