The Ixion FAQ/Font-of-wisdom

What kind of armour is there?

Subject: Impact protectors
To: ogri@vme.ccc.nottingham.ac.uk
Sender: trevs%uk.ac.sussex.epunix@vme.ccc.nottingham.ac.uk Content-Length: 2714

> What other sort of armor could there be? It's either some foam stuff
> of some rock hard plastic cup things that go around your elbows , knees
> etc that offer no impact protection.
>  
> Have you seen these Dainese thingies that go around your knees and elbows -
> they seem quite a good idea if you want to wear jeans or something in
> summer.
>  

There are two possible modes of operation for an impact protector:

• load spreading - the force from a small impact area is spread over a large area of bone, thus minimising the pressure (force/unit area) and reducing the risk of breakage.
• energy absorption - or the crumple zone effect - the material used deforms and absorbs the energy of impact (converting it into heat), so less pressure is applied to the bone.

Armorsport is apparently a fairly thin, low density foam - it sounds as though it would offer some energy absorption, but little load spreading.

Dainese armour is a double layer construction, with a hard outer casing, and a low-density foam on the inside. I was initially very enthusiastic about this until I looked closely. The foam layer looks like it will compress very quickly, and so won't absorb much energy. The outer layer has rather sharp edges, which look like they could cut through the foam very easily - I would worry about whether these protectors might actually cause injury.

Protek, and Suprotek (sp?) are a double layer high-density foam construction. The outer layer is quite hard, and operates both as a load spreader and energy absorber, whilst the inner layer is softer and operates as an energy absorber.

TPro standard. This is like Protek, but with an extra hard layer on the outside for load-spreading, and thinner high-density foam layers on the inside for energy-absorption.

TPro redline. Has a hard outside layer, and a high-density foam on the inside. In the middle there is some very-high-tech (VHT-tm) plasticine-like stuff, which is supposed to absorb energy as efficiently as a black-hole. The whole sandwich is about 7mm thick. This is supposed to be the best that money can buy (at the moment).

TPro does make the stuff in strap on form, They're at 36 Burr Street, Dunstable, Bedfordshire. LU6 3AG on 0586 471702

Example prices for a pair of elbow protectors for fitting in pockets inside suit. Protek, 18; TPro Standard, 28; TPro Redline, 40 (shoulder & knee prices are similar).

Trev.