9 replies to this topic

[blacktulip]

I have some omp harnesses that have a date of 2001. Are these fit for the bin only? They look immaculate but is that not the point?

[Avtovaz]

i have 2004 ones in my rally car, i can legally use them. I dont do stage events, i do road rallying.

 

If you have had them from new, and know their history, keep them, its when they get stretched in a crash is the problem.

[nicklouse]

Fine for any none FIA event. As above,

[blacktulip]

I don't know anything about their past so I might just donate them to a college or somewhere.

[Avtovaz]

why? If its a road car, just inspect them, check the stitching, look for snags etc and they will be fine. Just for motorsport there is this magic date thing...

 

What gets me is at work we have crains, and for lifting heavy stuff an insuance guy comes out once a year inspects all the lifting gear and gives them a coloured cable tie to say we can us them. Some of the straps are really old, he dosnt look at dates!

[cal844]

It's a common sense thing, in the short oval stuff they get replaced if they've been in a big shunt, but checked every meeting by two scrutineers, of which I do occasionally

[blacktulip]

why? If its a road car, just inspect them, check the stitching, look for snags etc and they will be fine. Just for motorsport there is this magic date thing...

What gets me is at work we have crains, and for lifting heavy stuff an insuance guy comes out once a year inspects all the lifting gear and gives them a coloured cable tie to say we can us them. Some of the straps are really old, he dosnt look at dates!

I was hoping to sell them on

[Jonesy77]

why? If its a road car, just inspect them, check the stitching, look for snags etc and they will be fine. Just for motorsport there is this magic date thing...

What gets me is at work we have crains, and for lifting heavy stuff an insuance guy comes out once a year inspects all the lifting gear and gives them a coloured cable tie to say we can us them. Some of the straps are really old, he dosnt look at dates!

I was hoping to sell them on

What colour and price ?

[Bobbins]

A little light reading ....

Harnesses and seat belts are woven from Nylon filament threads, time itself will not degrade the properties of the Nylon. However UV light, dirt and stretching will. UV light is not a big issue in a Mini but it contributes to the FIA 5yr ruling.

Nylon is used because it has a high level of elasticity (compared to other non-elastomeric fibres) and can have strain (stretch) applied to be repeatedly stretched from stationary and yet will return to its original position and still exhibit the same properties, hence why it's used in so many safety critical applications, slings, climbing ropes etc. and also ladies stockings & tights to avoid the saggy stockings look!

However ... as with all textile fibres there's a point where if too much stretch is applied the structure of the fibre is deformed, this is referred to as the yield point. Once the yield point is entered the fibre will not return to its original starting position but will start slightly longer. On stretching again it will take less strain to get to the yield point and might be deformed further, and repeat and repeat, the key being that the yield point does not move, it is still applicable to the original non-deformed fibre. The ability for the fibre to absorb energy is directly related to the strain needed to reach the yield point, if it's already stretched it's not going to stretch as far before losing it's strength and hence can't absorb the energy needed.

And this is the important bit - if a harness has had a big impact it's not going to have the same ability to absorb energy next time round even though it's strength at break will not have changed.

Whether this stops you buying a secondhand harness is personal choice, we all get secondhand seat belts when we buy a used car although they potentially may or may not have been subjected to the potential forces that a harness has in its intended application. Visual condition is usually a good influencer though, just check carefully around the mounting points where the webbing will exhibit the most damage at the point of impact.

Stu.

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[sonikk4]

Just to add a slant to this. Harnesses of Crew and Pilot seats.

 

Pilot seats have five point harnesses on inertia reels for the shoulder sections. Now these are fitted from new, no expiry date and serviceable on inspection. We look for Fraying, cuts tears etc etc.There are limits laid down in the maintenance manual and normally fraying limits are normally the first 10 strands for example. Tears and cuts generally U/S the harness.

 

Crew seats are normally 4 point with the same sort of limits. Again these are fitted from new and could if the crew looked after them last the life of the aircraft. And these do get abused. So the point being if they are in good condition with no visible signs of damage then still fit for use. The caveat being though as mentioned if being used for Motorsport. Then there will be limitations.