chrisf
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| posted on 28/7/05 at 11:59 PM |
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Pat:
I kinda agree with Rorty here. I think a second bar on your roll bar is in order. If I understand right, your idea seems a bit questionable.
For my mounts I did this: I welded a 3/16" plate on the underside of the upper chassis tube. Then, I drilled through the tube (and the plate)
and inserted a 2" long crush tube with an ID of 5/16". I then welded the top of the crush tube around on top and bottom. On mine, it is
maybe 1/4" proud of the upper tube.
--HTH, Chris
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kb58
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| posted on 29/7/05 at 03:05 AM |
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Rorty is correct. At best those posts will bend, allowing your head to get closer to the steering wheel then you can imagine. At worst they wrench
the tube sideways and rip out, allowing your face to impact the wheel.
However I disagree with the shoulder strap angles... follow this guide, http://www.gforce.com/pdf/harnessinstall.pdf
[Edited on 7/29/05 by kb58]
Mid-engine Locost - http://www.midlana.com
And the book - http://www.lulu.com/shop/kurt-bilinski/midlana/paperback/product-21330662.html
Kimini - a tube-frame, carbon shell, Honda Prelude VTEC mid-engine Mini: http://www.kimini.com
And its book -
http://www.lulu.com/shop/kurt-bilinski/kimini-how-to-design-and-build-a-mid-engine-sports-car-from-scratch/paperback/product-4858803.html
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Rorty
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| posted on 29/7/05 at 04:28 AM |
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KB, I think the shoulder belt angles in that document are way off. It's an ambiguous and contradictory article at best, which seems to have been
cobbled together from several other on-line articles.
They go to some lengths to explain how the human body stretches in an accident, yet they still recommend a shoulder strap angle of up to 30 degrees
above the driver's shoulders!
I just looked up harness mounting in the CAMS Manual. CAMS is the Confederation of Australian Motorsport (the equivalent of the MSA in Britain) and is
overseen by the FIA, so I figure if anyone would know about harness installation, they should. Interestingly, the manual states:
Schedule I - Safety Harnesses / Window Nets.
4 (ii) Full harness rear mounting points must be to a substantial part of the vehicle's structure, reinforced as may be appropriate.
(iii) On production cars, the original mounting points may be satisfactory.
I tried scanning the page with the diagrams, but the book is too stiff and the drawings feint, with the result it scanned poorly. But, CAMS recommend
the shoulder straps be up to 10 degrees below a horizontal line extending from the driver's shoulders. They further state anywhere up to
40 degrees below the same horizontal line is acceptable. That roughly supports what I said initially above.
They also show a drawing of a driver in a laid back seating position with a note stating in any event, the shoulder straps "may be best set
perpendicular to the upper spine".
In everything I ever read, saw, or was told about harness installation (including several safety lectures while an official scrutineer) the shoulder
straps should always be attached to the vehicle at some point below the driver's shoulders - never above!
The reasoning is, if the car was to flip, the driver's body can distort and if the straps rise above the shoulder line, the driver could squeeze
up into that area above the shoulders with the possibility of the driver's head contacting the upper roll cage or roof.
I've seen that happen with very unpleasant results. I would never allow a car on the track that had upward sloping shoulder straps.
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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Avoneer
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| posted on 29/7/05 at 06:42 AM |
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Please bear in mind that after SVA, they will be cut down flush with the top of the chassis bar.
Pat...
No trees were killed in the sending of this message.
However a large number of electrons were terribly inconvenienced.
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Rorty
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| posted on 29/7/05 at 07:00 AM |
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quote:
Originally posted by Avoneer
Please bear in mind that after SVA, they will be cut down flush with the top of the chassis bar.
Pat...
So you're not worried about the consequences if you happen to have an accident on the way to your SVA appointment?
Well at the very least Pat, weld those crush tubes in at an angle to match the strain direction of the straps. 
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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ned
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| posted on 29/7/05 at 08:53 AM |
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well you've seen my previous suggestion and theory, I'd tend to agree with Rorty on this, and i'd personally go for a 4 point
instead of a 3 point harness. can't give a good reason for this (other may be able to help me out here) but a 4 or even 6 point (if for track
use) is much better than a 3 point imho.
Ned.
beware, I've got yellow skin
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Fozzie
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| posted on 29/7/05 at 09:00 AM |
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I really do not want to get into any arguments here , I do not want to tell anyone how to build their car, or 'wee' on their fireworks,
but, I will say something if I do not think it is safe. I too have been involved in motor sport for many years, and part of our business is to prepare
cars for the race track, here in England.
I may have misread or indeed got this wrong, but I assumed that Pat (Avoneer) just wants to put his 'Book' Locost on the road, (SVA) and
not race it. That does not in anyway detract from advising the best possible harness thats available, but thats where we are governed by the SVA
'rules'.
The harnesses have to be of a certain type and 'E' marked, you MUST consult the SVA manual before purchasing them.
My car was built for road and race, and in my case, the belts I wished to use were not on the 'approved' list for SVA, although in theory
they were a lot safer, but the object was to get the car on the road first and change things if necessary later to suit the race regs and the
'Blue Book' (MSA).
Down here in Surrey, at the time of my SVA, they had a 'thing' about harness mounts and belts, I appreciate that in other parts of the
country other centres have different ideas, the only constant thing they have, is that there is no consistancy!
Pat, I can say, that there is no way that MK make/made their harness mounts for their 'Escort'/Book chassis anything like you have done (I
got my chassis late 2002). The 'bolts' did not come in centre line of the neck/spine, that is lethal (IMO), one bad whip of the neck, and
it could very well snap your spine (IMO)
The only fault I found with their harness mounts were that they were not central to the seats, ie they did not come in the centre line of each
shoulder, and if I had used them , I would have been in danger of slicing my neck, also the height was wrong, they did not meet the height requirement
required for SVA with or without the seat in place.
I did speak to MK at the time, and they told me that they were made to be used with their seats, which of course I was not using.
I was not convinced, but I do accept that there may have been a boo-boo with my chassis, and I had to rectify that issue.
Pat, can I suggest, that before you go any further, that you look at a few 'Escort' (Book) based chassis? I do not know where you live in
relation to MK or other chassis manufacturers, or indeed other 'book' locosters, but I feel that you ought to look into the mount issues
further. As I said earlier, I do not want to tell you how to build your car, but we all want you to get through the SVA but also be safe on the
road.
Rorty has made very valid points with regard to the whip=lash effect, it is a grave concern, and if you were down here, I know it would not get
through SVA, and I am sorry to say this, but the construction is no where near strong enough, or suitable.
This is all in my opinion only of course.
Fozzie
'Racing is Life!...anything before or after is just waiting'....Steve McQueen
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James
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| posted on 29/7/05 at 09:59 AM |
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The MK chassis are done with two 40-50mm long) threaded tubes welded to the back of the square bar.
With the more recent ones having a gusset around them for added strength after a few SVA failures.
The ever helpful photo archive of Bob:
http://www.locostbuilders.co.uk/photos.php?action=showphoto&photo=in_boot1.jpg
I'm under the impression that the square top rail of an MK is slightly taller than a book car though- which helps get the 460mm I guess!
IIRC my SVA book says that you should be prepared for an accident where the pull on the belt mounts is 10G!!!
So if you weigh 80Kg (12.5st) that's 800Kg on the mount....
Just bear that in mind folks! 
Cheers,
James
------------------------------------------------------------------------------------------------------------
"The fight is won or lost far away from witnesses, behind the lines, in the gym and out there on the road, long before I dance under those lights."
- Muhammad Ali
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Avoneer
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| posted on 29/7/05 at 11:14 AM |
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Thanks everyone, didn't mean to upset anyone!
I have "E" marked 4 point harnesses, but have always found the mounting points on various cars to be too far apart and they
"drop" off the shoulders so I was going to use one central mounting point for the top two "clips" of the harness.
As I am only 5'6", my seat is almost 12" from the back of the chassis so I don't think I'm in danger of catching my neck
on it.
I has originally intended to mount the tube through the chassis top rail, but was worried about weakening the top chassis rail.
So to try and "be safe" can I use one single central point mounting, welded through the top tube?
A lot of the locosts I have seen have a threaded tube (longer than mine) welded to the top of the chassis tube and reinforced behind with a small
plate - surely this won't be as strong as mine would have been welded to the back with a triangular gusset in front?
Pat...
No trees were killed in the sending of this message.
However a large number of electrons were terribly inconvenienced.
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Fred W B
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| posted on 29/7/05 at 11:22 AM |
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With regard to Whiplash, I was under the impression that race regs require a raised seat back or seperate pad behind the head/helmet of a driver, to
reduce whiplash injuries and avoid any possibility of a head being trapped under a bar that might buckle if actually used in anger i.e car upside
down. Sounds like a good idea to me , and a feature I am ging to put on my car (with a removable one on the passenger side)
Another point on strength of belt mounting points, does the group think that there could be a point where the belt attchment points could be too
rigid, in that a bit of deformation in the chassis could reduce the G force transmitted to the person in a dead stop head on collision, or would the
inherent belt stretch always deal with this?
Cheers
Fred W B
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ned
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| posted on 29/7/05 at 11:42 AM |
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I would suggest that chassis deformation of the harness mounting points would need to be thoroughly tested (if ever proven to work) and certifiable or
sva'able as an accident/impact safety feature. I think this would be well beyond the remit of any locost, though an interesting point fred.
Ned.
beware, I've got yellow skin
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Dale
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| posted on 29/7/05 at 11:46 AM |
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Just had to say that this is a very good thread. I will not be having to go through an sva but learning anything about increasing our safety and
passengers is always good.
Thanks
Dale
Thanks
Dale
my 14 and11 year old boys 22
and 19 now want to drive but have to be 25 before insurance will allow. Finally on the road
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Peteff
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| posted on 29/7/05 at 12:07 PM |
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I think if the belts are mounted lower than your shoulder you would cause them to pull down on your spine (submarining) causing damage to shoulders
and compressing the spine I still think the rollbar crossmember is the easiest way round it.
 
Rescued attachment beltfitting.jpg
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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Fozzie
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| posted on 29/7/05 at 12:10 PM |
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Fred, in racing, no doubt you are right, but we are talking road car here, the laws with regard to head pads wouldn't apply.
I think also, that you will find that our cars with the extra horizontal bar added, have only added probably less than 2 inches above chassis rail, so
no chance of head getting trapped there.And if your harnesses are properly fitted and tight, you wont be 'flung' anywhere, your
belts/harness should be doing their job!
BTW sorry if I have misread above postings, trying to do too many things at once....as usual
ATB Fozzie
'Racing is Life!...anything before or after is just waiting'....Steve McQueen
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Rorty
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| posted on 29/7/05 at 01:47 PM |
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There has been quite a bit of talk about racing standards (some of it by me), and I am aware Avoneer's car is not being built for racing, but I
think when safety is an issue, it pays to investigate the highest current standards.
Pat, as Foggie says, your first point of reference should be the SVA manual. I would subsequently pay your local (or wherever you intend taking your
car for its test) SVA centre and seek their views or reassurance on your proposed harness mounts.
Controlled chassis deformation is a very complex area and I wouldn't suggest anyone without extensive experience even go there. There is no need
for the harness mounting points to "give" in an accident as long as reliable harnesses or seatbelts are employed. Current seat restraints
are made from Nylon webbing which actually stretches when heavily loaded. This is by design and not a flaw.
A number of years ago some cheap harnesses made from polyester webbing (the non-stretch stuff as used in load restraints and tie-downs) came on the
market from somewhere like Taiwan. 
Even the type of thread used for stitching the webbing is critical. I received a circular from CAMS quite recently warning about some faulty harnesses
which had suffered catastrophic failure of the stitching. Good quality safety gear is really a must.
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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ned
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| posted on 29/7/05 at 02:01 PM |
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quote:
Originally posted by Rorty
Pat, as Foggie says,
who's foggie?
beware, I've got yellow skin
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Fozzie
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| posted on 29/7/05 at 02:02 PM |
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Absolutely Rorty!
I totally agree with you in regard to using the highest standard of harnesses available.
Unfortunately, the SVA's requirements are not as stringent as I personally would like to see in that regard.
ATB Fozzie......(aka..foggie...lol)
'Racing is Life!...anything before or after is just waiting'....Steve McQueen
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Rorty
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| posted on 29/7/05 at 02:17 PM |
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quote:
Originally posted by ned
quote:
Originally posted by Rorty
Pat, as Foggie says,
who's foggie?
Ooops! I've let the cat out of the bag now! Fozzie's real name is Foggie ... or maybe I can't read... or maybe it's 12:20am
and I'm tired.
Ted, I knew who I meant even if you don't!
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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Rorty
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| posted on 29/7/05 at 02:38 PM |
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Not the same as the car in question, but here's an aftermarket harness bar fitted to a Porsche:
and another Porsche (Boxster):
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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Fozzie
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| posted on 29/7/05 at 02:43 PM |
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LOLOLOL
Get some Zzzzzz's mate ya right, its late in the Antipodes...
ATB Fozzie/Foggie.....
ps Foggie IS more apt today, but Ted 'Flanders' just don't sound right......
'Racing is Life!...anything before or after is just waiting'....Steve McQueen
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ned
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| posted on 29/7/05 at 02:56 PM |
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lol sleep well rorty
beware, I've got yellow skin
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Avoneer
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| posted on 29/7/05 at 03:38 PM |
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Hi Guys,
Yep - very imformative thread and I'm trying to find a solution without upsetting everyone!
Beasically, I have 4 threaded inserts and eye bolts which I want to use without adding to much weight to the chassis.
I can use all four or just two (one for each side).
I can't have a horizontal bar on my cage as I have a diagonal welded in.
If I did it lke the attached pic, the only problem I could see would be the twisting force on the chassis bar, which would be there even with several
different mounting variations, but could be reinforced with bracing from this top bar down to the middle bar.
Any further suggestions/constructive critisism would be greatly appreciated as this will not only help me in the long run.
Thanks,
Pat...
No trees were killed in the sending of this message.
However a large number of electrons were terribly inconvenienced.
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Avoneer
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| posted on 29/7/05 at 03:43 PM |
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That has to be better than the MK (pic from the link above):
 
Rescued attachment in_boot1.jpg
No trees were killed in the sending of this message.
However a large number of electrons were terribly inconvenienced.
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Fozzie
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| posted on 29/7/05 at 04:07 PM |
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Pat, Have look again at my car again on page 1, I too have a diagonal in my MK roll cage!
If that is a picture (above) of the MK harness mounts, then all I can say, is, mine looked nowt like that!, but that was before the
'new' MK came to be.
Fozzie
'Racing is Life!...anything before or after is just waiting'....Steve McQueen
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Avoneer
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| posted on 29/7/05 at 04:44 PM |
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Hi Fozzie,
Thanks for the reply.
My hoop is already welded and there is no room for a horizontal bar - there was on my Avon and that how my belts are mounted on that car.
In the book - two ugly slugs were all that was used and this was for racing - I know times have changed, but they must have been stong enough then.
I know the newer MK chassis has changed and the inner mounts have a plate on them just like the ones in my pic above.
Is the only problem that mine are too long???
I just don't get it when this method is fine for many of the manafacturers cars and appears to be the norm.
Pat...
[Edited on 29/7/05 by Avoneer]
No trees were killed in the sending of this message.
However a large number of electrons were terribly inconvenienced.
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