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  #1  
Old 09-10-2008, 04:45 PM
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Default Broken or lost legs in crash

I know of one person that lost their legs in a vari crash, these birds have nearly no structure ahead of the IP and it crushes, breaking your legs or worse making it so you have no legs

Well, this problem has been bothering me for quite some time and i had an improvement. I was going to install braces from the top of the ip to the bottom of the next forward bulkhead and call it a day.

Just talked to a buddy and he convinced me that a better solution was to just double up the fuselage side in the entire area with 3/8 foam and a couple layers of bid

That is my solution
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  #2  
Old 09-10-2008, 10:09 PM
Remi Khu Remi Khu is offline
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Default Re: Broken or lost legs in crash

The Indy cars have crush zones, which absorb the energy. In the canards, the crush zone is the nose... if one stiffens the nose, then I'm afraid the energy will be transferred to the cockpit, and perhaps more damage will ensue.

This topic was recently discussed ad nauseum on one of the canard type email lists.

The take home message is: something's gonna break, pick the part.

-- Remi
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  #3  
Old 09-10-2008, 10:36 PM
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Default Re: Broken or lost legs in crash

Well I tire of the ad nauseum.

The part is weak and is not a designed as a "crush zone", it is a part of the plane that contains my body parts. I don't want those parts to crush.

If you make a lawn dart of the plane - you will die, simple as that.

if you make a strong boat of the plane that can travel on the ground in a bad, bad sorta landing, that is the plane i wants and am building.

The plane has plenty of structure behind the IP, just not much in front of it.

What convinced me to beef it up - a talk with the hanger mate of the guy or one of the guys that lost his legs, that was my wakeup call.
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  #4  
Old 09-12-2008, 11:49 AM
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Default Re: Broken or lost legs in crash

i really really dislike reengineering the plane.

Contrary to public opinion, i am a plane follower not a plane innovator.

This propensity of leg area of the plane collapsing should have been solved years ago by real engineers, not attempted to solve it by me.

One guy is yelling at me to put in a 1x2 rectangle out of uni from the top of the forward face of the ip down to the next forward bulkhead, making sure of keeping it straight.

Another is saying, put a full sheet of 3/8th with glass on it in the entire area

Love to plane follow, hate to plane lead

I will do something and hope i never test it

One thing i will not do is poke my head in the sand and ignore it or poke my head in the sand and justify that it is the right place to have a crush zone.
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  #5  
Old 09-15-2008, 02:43 PM
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Default Re: Broken or lost legs in crash

Quote:
these birds have nearly no structure ahead of the IP and it crushes
You should read Beagle's story about his crash and how it held together after hitting powerlines. Also there are others who have flipped their planes with the nose still attached.

Agreed it has it limits and should be reinforced.


Quote:
The Indy cars have crush zones, which absorb the energy. In the canards, the crush zone is the nose... if one stiffens the nose, then I'm afraid the energy will be transferred to the cockpit, and perhaps more damage will ensue.
Nose was not designed as a crush zone. I remember that conversation and conclusion. I'll keep my legs thank you.

I wil not go on and brag like some folks that I am a mechanical or aeronautical engineer so I'm smart and you should not post ideas. I will say based on my long history of successes in root cause analysis you need to prevent the cause of the crash otherwise you just might as well wear a helmet and parachute whenever you fly as well.
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  #6  
Old 10-21-2008, 01:26 PM
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Bowlersaid Bowlersaid is offline
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Default Re: Broken or lost legs in crash

Might this be a discussion in favor of retract - Mains?

Seems like the fixed gear increases the nose down forces...

Seems like belly landing with gear up would be preferable....

Just leaving that out there...

Moe slaps Curly "SMACK" - curly,"what'd U do that for?"
Moe," Every time you think, you weaken the nation"
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  #7  
Old 10-22-2008, 03:39 PM
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Default Re: Broken or lost legs in crash

I believe if you add something to your plane that doesn't interfere with its original design the do it. Adding another 3/8 glassed panel to the sides forward of the IP will do nothing but add a couple pounds and lose 3/4 interior width. No biggie if it makes one feel more secure. Unfortunately I don't think it will save your legs at a 50 - 90 mph nose crash. What will happen will happen when 2000+ pounds continues moving after the nose stops. Car companies spend millions for safety at these speeds.
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  #8  
Old 03-11-2009, 12:24 PM
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Default Re: Broken or lost legs in crash

well, went to run the brake lines and install the parking brake last night and noticed that i would be in the area i want to reinforce for saving my pink parts in the event of a bad off field landing. Not a lawn dart landing, a bad off field landing, you know, the kind people have lost legs in because the plane colapses in front of the IP.

Was going to and cut foam to reinforce the side from bottom forward at the rudder pedal bulkhead to top where the ip meets the side. Then i looked at a small piece of foam with 2 sides of glass and it was bent and easily de-laminated.

Well, foam is the wrong material, we decided, well I decided and my buddy the aeronautical engineer, A&P agreed that my choice of 1/4 inch covered with 6 layered of uni finnish birch plywood was a good choice.

So it be written, so it be done! i have the foam templet in the truck to make the birch from tonight. oh yeah, guitar boy is comin tonight to work on his guitar!

You know, if i would have realized that the stagger EZ was designed with a keel to solve this issue, i probably would have followed his lead and built a stagger EZ, safety is number one and i like my pink parts.
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dust

maker of wood, fiberglass, foam dust, metal bits and one day a Cozy will pop out and swiftly whisk me from meeting old friends and family to adventures throughout the world

Last edited by Dust : 03-11-2009 at 12:30 PM.
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  #9  
Old 03-13-2009, 11:25 AM
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Default Re: Broken or lost legs in crash

Well, just got off the vid with a cozy flier, he met a long pilot who lost his legs in a long accident.

I met a vari flier whose hanger-mate, well prehangermate, lost his legs in a vari accident.

Can't imagine why i think there is a problem that should be solved
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dust

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  #10  
Old 03-16-2009, 11:35 AM
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Default Re: Broken or lost legs in crash

Nice to be able to lay up glass again - temps were good over the weekend, saturday installed plywood reinforcement with finish nails and flox, sunday glassed it over with 4 layers of uni, now the brakes can be finished.
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dust

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  #11  
Old 03-16-2009, 11:46 PM
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Default Re: Broken or lost legs in crash

Quote:
Well, foam is the wrong material, we decided, well I decided and my buddy the aeronautical engineer, A&P agreed that my choice of 1/4 inch covered with 6 layered of uni finish birch plywood was a good choice.
Do you remember the strength of that glass/foam stick you made (well, I did) in ch.3 or 4 to learn layups? Awfully strong..
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  #12  
Old 03-17-2009, 09:54 AM
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Default Re: Broken or lost legs in crash

well, i used 4 layers uni and the finnish birch plywood, one done one to go. The plywood is for toughness

Hope i never test it out. Now i can install the parking brake and brake lines.

Steps
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dust

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  #13  
Old 03-04-2010, 09:53 PM
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Default Re: Broken or lost legs in crash

pic of the brace
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