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Seat Belt Restraint Points

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jrgowing(at)bigpond.net.a
Guest

Posted: Sat Jan 17, 2009 4:09 pm Post subject: Seat Belt Restraint Points

Fellow Builders

  

 The restraint point in the headrests has been of  concern to most of us because they is below shoulder  height. There have been proposals made to raise the headrests and  also to hinge additional height from behind to lift the direction of the  belts. However they all seem to impede access some extent.

  

 Why cannot we have a restraint point in the  fuselage shell situated well behind, and at a little lower  level than the fuel filler?  This would  still not be  perfect as the line of restraint would be toward a little inboard  of directly behind the crew members, but not much.

  

 The pair of restraint points I am proposing  can be set as follows:-

 Measure inside the fuselage and  mark a location 18 2 behind the door frame and 15 2 up from the top  edge of the lower fuselage shell at the joint line. You will find  this spot to be about 6 2 above the top of the  corresponding headrest and about midway between the door frame and the  sloping wall of the baggage bay. 

  

 There is good space around this to reinforce the  shell of the fuselage with say 2 plies of bid approx 12 2 square, an aluminium  plate,  and perhaps 4 or more plies of bid of decreasing  sizes after the first (say 2 2 less on each one).

  

 I have noted that quite large plates  have been used in the head rests but much smaller ones in the  fuselage sides for the lap belts. Perhaps the new ones ( 5 2x3 2 as in the  headrests or smaller?) could be perforated for better adhesion and set in  flox.

  

 Now,

  if there is a qualified person willing to  confirm the safety of this proposed modification, then at least I, and  I guess quite a few more builders, will be pleased to transfer their bolts and  washers from the headrests!

  

 Comments welcome!

 Especially an engineering approval!

  

  to

  

 J R (Bob) Gowing UK Kit 327 in Oz

 24 High St

 Bega NSW 2550

 02 6492 3294

  

  



I am using the Free version of SPAMfighterWe are a community of 5.8 million users fightie Professional version does not have this message    [quote][b]

rparigor(at)suffolk.lib.n
Guest

Posted: Sat Jan 17, 2009 5:25 pm Post subject: Seat Belt Restraint Points

Hi Bob



I agree that the angle of shoulder harness when attached as per manual is

less than desirable.



Keep in mind that when those attachments are called upon for integrity,

there could be two "large" passengers doing the tugging, and it may not

just be forward loads,  could be negative, and or side loaded. As far as

the attachments go, forward tugging will not only try tearing out with

forward loading, but downward loading as well.



I ground some numbers and did a reasonable amount of destructive testing

and came up with what I feel has a good chance of doing what I think a

shoulder should do if called upon:



See Rollbar/Shoulder Harness in two albums:

http://www.europaowners.org/modules.php?set_albumName=Begin-06-2003&op=modload&name=gallery&file=index&include=view_album.php



Lets just do a simple calculation, take a 200lb pilot, lets say 1/2 the

weight is on shoulder harness and take a 10 G stop, that's 2000lbs, now if

the shoulder harness was pulling at a 45 degree angle (that it shouldn't

be doing, recommended is 30 positive and 5 negative), that's pulling on

attachment point 4000lbs. Will your attachment be able to withstand 2

tons?



I forget the exact numbers I used, but did research quite a bit to come up

with them and will provide if required. My simple calculation may be quite

a bit off, I forget the details, but there is a good chance that it is not

50% off.



If for the most part the loads are going to be in the forward direction,

UNI is a good choice for majority of frontal loading.



We took advantage of the aft door sill which when reinforced is a very

strong structure.



Ron Parigoris



BTW I think it's Steve Crimms Europa (now sold, forget Builder's name) has

a metal plate glassed in place, I think similar to what you propose.

fklein(at)orcasonline.com
Guest

Posted: Sun Jan 18, 2009 1:47 pm Post subject: Seat Belt Restraint Points

On Jan 17, 2009, at 4:07 PM, JR Gowing wrote:

 	  Quote: 	
		   

The restraint point in the headrests has been of concern to most of us because they is below shoulder height. There have been proposals made to raise the headrests and also to hinge additional height from behind to lift the direction of the belts. However they all seem to impede access some extent.

 

Why cannot we have a restraint point in the fuselage shell situated well behind, and at a little lower level than the fuel filler?  

	




Bob,

I share your concerns and gave the issue a fair amount of thought. What stopped me from establishing restraint points as you suggest were:

- the limitation of my own knowledge as to how much stress could be applied to the fuselage top shell, how it could be adequately distributed, and a concern that if it were ever needed, the result could break the back of Ms. Europa.

- a concern about dealing w/ potential side loads given the distance of such a restraint point from the seat back which might allow too much sideways movement of the shoulder harness,

- and a concern that whatever strap or cable might lead to such a restraint point could be bothersome when loading/unloading baggage, possibly requiring disengagement from the harness.

I settled on that little hinged riser (photos previously posted) because:

- it allowed for standard method of entering and leaving the cabin,

- all stresses could be routed to the CM as designed via the existing shoulder harness attach point,

- the riser could be bench-tested to ensure that it would not fail (in compression); I put what would be a tension force of 1500# in the harness at the appropriate angle and the little hinged riser absorbed it w/ no sweat; however, the force was applied incrementally rather than abruptly. I was figuring 100# upper body weight...so, theoretically, the riser may be good for 15G,

- and, when hinged back, it served to increase the area upon which one can sit while entering/exiting, and the approximately 4" x 6" area IMO only marginally reduced access to the baggage bay.

At the time I made mine, I actually bought enough material to produce a few "kits", but have set that notion aside as I've proceeded with my build. Incidentally, one aspect of this solution is that it allows the use of the standard harness and can be added at any time.

Fred

A194



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jrgowing(at)bigpond.net.a
Guest

Posted: Sun Jan 18, 2009 3:06 pm Post subject: Seat Belt Restraint Points

Fred

 Thank you for your reply. Interesting information  is coming.

  

 I did not take up the  2folding top 2 before because  I thought the top down would take up too much room in loading baggage- but it  occurs to me now that it could easily be folded and unfolded to suit the moment.  Before it just seemed like unnecessary clutter.

  

 It did not occur to me that it would make the  headrest into a much bigger and much more comfortable seat as well as  correcting the angle of the belts!

  

 Maybe I am on the wrong track with the longer belt  to the back? If you still have the folding seat details handy in your  computer, I would be pleased if could email them to me so I can study it  again. (I have not done any searches of the database yet and am slow to  learn.)

  

 JR (Bob) Gowing UK Kit 327 in Oz

  

  

  

  

 ---

fklein(at)orcasonline.com
Guest

Posted: Sun Jan 18, 2009 6:31 pm Post subject: Seat Belt Restraint Points

On Jan 18, 2009, at 3:02 PM, JR Gowing wrote:

 	  Quote: 	
		  Interesting information is coming. 	




Bob,

	Info to be revealed in due time?



 	  Quote: 	
		  f you still have the folding seat details handy in your computer, I would be pleased if could email them to me so I can study it again. 	




	'fraid I don't use my computer for graphics...I'm one of those Neanderthals still drawing lines...here are a couple pixs:



Fred

A194

[img]cid:A7F4C5AF-38D8-4510-93BF-8FC8DEE930A5[/img]

[img]cid:60D5859E-7217-4DE5-B469-B091A92FD0D9[/img]

[img]cid:E00C4634-522D-466B-9C60-25D717817613[/img]



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jrgowing(at)bigpond.net.a
Guest

Posted: Mon Jan 19, 2009 7:33 pm Post subject: Seat Belt Restraint Points

Fred

  

 It folding headrest arrangement now  looks a hundred times better than I thought when I first saw  it!

 Especially since you mentioned how  it increas the size of the sitting area when it is  folded.

 I understood that you are sending more info by  some means so will be patient. 

 But if not then please tell me.

  

 Many thanks for the  photos and 

 Best Wishes

 JR UK Kit 327 in Oz

  

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fklein(at)orcasonline.com
Guest

Posted: Mon Jan 19, 2009 9:19 pm Post subject: Seat Belt Restraint Points

On Jan 19, 2009, at 7:30 PM, JR Gowing wrote:

 	  Quote: 	
		  It folding headrest arrangement now looks a hundred times better than I thought when I first saw it!

Especially since you mentioned how it increas the size of the sitting area when it is folded.

I understood that you are sending more info by some means so will be patient.

But if not then please tell me.

	




Bob,

I thought you were joshing me about the increase in size of sitting area...believe me, that was an unanticipated plus...the critical thing (at least to me at the time) was to not have to sit on a knife-edge!

Let me see if I can scan a drawing into a form which I can send to you, along w/ some add'l pixs....say, tomorrow, or the day after!

Cheers,

Fred



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jrgowing(at)bigpond.net.a
Guest

Posted: Tue Jan 20, 2009 7:05 pm Post subject: Seat Belt Restraint Points

Fred

  

 Don't bother trying to get up more pictures - I can  see from the ones you already sent that I ought to do the mod.

 What I need now is the plan/details  - 

  

 and if anyone has already made parts to  spare.

  

 JR (Bob) Gowing UK Kit 327 in oz

  

 [quote]   ---

rampil

Joined: 04 May 2007
Posts: 870

Posted: Wed Jan 21, 2009 12:11 pm Post subject: Re: Seat Belt Restraint Points

Hi Bob,



Sorry for the delay in my response about belt attachments.



I followed the guidance of AC21-34 (?, but cited in this group in 2007)

I also showed it to Andy Draper at SnF when he was still with Europa,

and he thought it a reasonable approach.  I designed and put it together

under the  watchful eyes of Bud and Russell at FC.



Simply, I bonded aluminum attach points to the lateral seam of the

fuselage behind the baggage bulkhead about a foot. The initial bonding

was with Redux and the bracket was perforated with lightening holes

through which floxxed Redux protruded. This was buried under 4 plies

of BID each 18-20 inches square.  A steel shackle was professionally

crimped at a marina to 1/4" steel cable to the common shackle for

the shoulder belts. The cables run through small holes in the D bulkhead.

This raises the belt angle to approximately level from the shoulder to

seam attach.  I have a professional interest in the biomechanics of

aircraft injuries and have treated several pilots with head injuries

and spinal compression fractures.  I feel much better about my

approach than the factory standard. Of course the proof will be in the 

pudding after a spike deceleration.

_________________
Ira N224XS

jrgowing(at)bigpond.net.a
Guest

Posted: Thu Jan 22, 2009 3:41 am Post subject: Seat Belt Restraint Points

Ira

Thank you for your reply. It seems that Europa could have done a better job 

but in rushing against time and money you can't get everything exactly 

right!



It sounds as if your idea would anchor you in alright - but the attachment 

would be very long.



Best Wishes

JR (bob) Gowing

---

steven.pitt2(at)ntlworld.
Guest

Posted: Thu Jan 22, 2009 5:24 am Post subject: Seat Belt Restraint Points

Gentlemen and ladies,

I have only just picked up on this thread and thought I would pass on 

discussions that I had with Andy 3 years ago when he was the lone Europa rep 

at Sun'n'Fun.

We discussed repositioning the upper restraint and the suggestion was to 

build in a hard point where the 'd' panel met the roof behind the seats. The 

restraint would need careful positioning to get the straight pull for both 

seatbelts but Andy did a quick 'bag of fag packet' calculation that the 

shear and direct pull forces could be accomodated by this repositioning.

Nothing further was done with this idea as he was to move to the PFA 

straight after the show.

I hope that this is of assistance and that someone might pursue this idea.

Regards

Steve Pitt

G-SMDH

PS the gang from the UK will be at Sun'n'Fun again this year so here's to 

meeting up with old friends again. I have been advised that the stands are 

N99 and N100.



---

rick(at)amimotormanagemen
Guest

Posted: Thu Jan 22, 2009 6:53 am Post subject: Seat Belt Restraint Points

Hi Steve



Regarding S & F lets hope we can get a DOTH for 24th or 25th April at

Lakeland! The Virgin Atlantic and BA fares are good for the 23rd on as the

school hols are over.



Cheers



Rick

G-RIKS 



--

fklein(at)orcasonline.com
Guest

Posted: Thu Jan 22, 2009 8:02 am Post subject: Seat Belt Restraint Points

On Jan 22, 2009, at 4:35 AM, Steve Pitt wrote:



 	  Quote: 	
		    a quick 'bag of fag packet' calculation


	


..now that's a new one for me...and a keeper...



do not archive

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ptag.dev(at)tiscali.co.uk
Guest

Posted: Thu Jan 22, 2009 12:21 pm Post subject: Seat Belt Restraint Points

Hi! Fred

I saw that and presumed a typo since I've only ever heard of "Back of

Fag Packet" calculations ?

Regards

Bob Harrison G-PTG

Do not archive.



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