REFLECTOR: Accident report - SQ2000

Jim Sower canarder at frontiernet.net
Fri Sep 23 20:59:33 CDT 2005


I don't think the seats save drivers by themselves.  They encapsulate 
and immobilize the driver while the rest of the car progressively 
disintegrates, absorbing nearly all the energy of the crash relatively 
gradually.  I'm pretty sure that if you dropped that seat with that foam 
from say, 10-15 ft and compared it with the factory seat that would 
crush and decelerate you over a longer distance, you'd sustain  
comparable or less injury  At a given speed at impact, it's the "length 
of the stroke" or distance over which you accelerate that drives 
severity of injury.  Memory foam has a 1" or 2" stroke.  The stock seat 
has softer, less effective foam for the same couple of inches, but a 
steel structure that's going to absorb a little energy as it collapses. 

If you crashed a 50s or 60s race car with your cutting edge seat 
installed, you'd be just as dead as if you had the original seat because 
the car stays together and transfers all the loads to your tender ass 
instead of absorbing most of the energy shedding parts.

It's moot anyway, since as a practical matter, you can't design an 
airplane to crush and break up in the huge variety of crashes and still 
stay together while flying.

Ejection seats anyone?  Your light foam number with a rocket on it might 
do some good ... Jim S.

Tom Martino wrote:

>You think form fitting, memory foam and helmet type seas will kill you faster that Velocity factory seats?  Perhaps you should inform NASCAR?  And every other racer in the country ... since these types seats have been saving lives for years in major collision on the track.
>
>
>-----Original Message-----
>From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Jim Sower
>Sent: Friday, September 23, 2005 3:18 PM
>To: Velocity Aircraft Owners and Builders list
>Subject: Re: REFLECTOR: Accident report - SQ2000 [heur]
>
><... At some G-loading it's the body that would break anyway and not the seat...>
>Actually, I think the rigidly anchored, form fitting, temper/memory foam covered seats that have been discussed will kill you quicker than the factory seats.  Crash survivability turns on structure crushing/breaking and absorbing energy.  The factory seats have [a little of] that.  Temper foam (or any other cushion for that matter) is comfortable, but useless for absorbing impact energy. A good 4-point restraint is as good as you can do IMO, but I haven't seen one in a Velocity.  Cozys and EZs have them, but they have rigid, structural seats, so there's no impact energy absorption.
>
>Composite planes are just too damn strong to be crash worthy ... Jim S. 
>
>
>
>Carruth, Joel L wrote:
>
>  
>
>>I agree that the seats are a somewhat flimsy. However, correct me if I missed something here, but from the last picture (100-3047) of the cockpit, it appears that the hinges are still intact - at least not broken. It looks more like the #10 screws were either sheared off or pulled from the aluminum hard point. 
>>
>>Assuming you stay with the factory seat (less $), it seems that the following would be necessary:
>>1) Instead of #10s, use some AN-3s. With a doubler+nutplate on the inside.
>>2) Extra glass (3 BID??, UNI?) moving up the sides covering the aluminum attach point and doubler.  Perhaps some UNI going from side-to-side at shoulder blade height. 
>>
>>Probably not as good as an engineered seat, but it will definitely help. At some G-loading it's the body that would break anyway and not the seat. 
>>
>>Any other reinforcement ideas?
>>
>>Joel Carruth
>>Lockheed Martin 
>>JSF - Pilot System Software
>>W: (817) 763-4337
>>Fax: (817) 777-8378
>>joel.l.carruth at lmco.com
>>
>>-----Original Message-----
>>From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Scott Derrick
>>Sent: Thursday, September 22, 2005 7:21 PM
>>To: Velocity Aircraft Owners and Builders list
>>Subject: Re: REFLECTOR: Accident report - SQ2000
>>
>>There are seats for race cars available that are very light and designed 
>>for high speed car crashes. 
>>
>>I ave an 97 Std. and the seats are part of the air frame.  I can't see 
>>them coming apart, but I also can't seem them offering any crush to 
>>lessen thr impact.
>>
>>Scott
>>
>>Chuck Jensen wrote:
>>
>> 
>>
>>    
>>
>>>The solution that was put into my plane was seats out of a Corvette.  They are low profile (to enable the low-slung Vette look) and seem to be substantial, yet don't seem to weight much.  Semi-reclining type auto seats may be worth a look.
>>>
>>>Chuck
>>>
>>>-----Original Message-----
>>>From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Tom Martino
>>>Sent: Thursday, September 22, 2005 12:37 PM
>>>To: Velocity Aircraft Owners and Builders list
>>>Subject: RE: REFLECTOR: Accident report - SQ2000 
>>>
>>>This comes at the exact time that I pulled my seats because I decided they are flimsy.  One day while flying in chop ... I felt my self being bounced a couple of times up against the seat back ... and I did not like the feeling.  The seat back seems weak.
>>>
>>>
>>>I am molding buckets that attach to the floor directly.  The "buckets" will be lined with a system of shock absorbing material (like in a helmet) with memory foam on top.
>>>
>>>The bucket is one piece bottom and back, with some flex ... but no "joints".  It will cradle my body somewhat like a clam-shell.  I call it a seat helmet or "pod".
>>>
>>>I totally agree with many accident findings that forced landings and rapid descents often turn fatal due to inadequate restraint, shock absorption and seat structure.  I hope to overcome these weaknesses.
>>>
>>>Tom Martino  
>>>
>>>-----Original Message-----
>>>From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Jim Sower
>>>Sent: Thursday, September 22, 2005 10:10 AM
>>>To: Velocity Aircraft Owners and Builders list
>>>Subject: Re: REFLECTOR: Accident report - SQ2000 [heur]
>>>
>>>I seem to recall that Paul bought his seats from Velocity - along with 
>>>some other things. I never liked the seat structure but accepted that, 
>>>like spam cans, the seat has little or nothing to do with restraint - 
>>>the harness being bolted to the airframe. I further assumed that the 
>>>seat structure would crush on vertical impact and therefore be of some 
>>>benefit in absorbing energy. I'm skeptical about the plane springing 
>>>backwards as I am about intimations that he was flying out of limits aft CG.
>>>
>>>I assumed that the Velocity restraint structure had been tested 
>>>satisfactorily ... Jim S.
>>>
>>>Al Gietzen wrote:
>>>
>>>
>>>
>>>   
>>>
>>>      
>>>
>>>>Some of you may have seen this on other venues. This is not happy 
>>>>reading but I post it here because of one factor that relates to our 
>>>>airplanes - the seats.
>>>>
>>>>You can skip the rest of the report, but note that the lack of 
>>>>seatback support is cited as a cause in the pilots death. The seat is 
>>>>essentially the same as the Velocity. From the first time I saw the 
>>>>Velocity seats I was very concerned that is provides very little 
>>>>support against strong forces vertically or from the rear. Once the 
>>>>back support breaks there is no longer a restraint system.
>>>>
>>>>And speaking of restraint system, I also pressed the factory years ago 
>>>>for some test of the 5/16" bolt threaded into ¼" aluminum block as an 
>>>>adequate seat belt attachment; particularly for the inboard side of 
>>>>the front seat.
>>>>
>>>>The analysis of the 4 canardians who examined the wreckage of Paul 
>>>>Conner's aircraft is now available at:
>>>>
>>>>     
>>>>
>>>>        
>>>>
>>http://www.cozybuilders.org/N2992_Accident_Eval/
>>
>> 
>>
>>    
>>
>>>>Al
>>>>
>>>>------------------------------------------------------------------------
>>>>
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