Damo
Well-known member
- Messages
- 2,580
- Location
- Bedfordshire
I read a lot of posts about crash tested systems and a lot of the information/opinions i read are incorrect.
This is taken from the horses mouth.
[media]
[/media]
The video you are referring to of the 'tank fail' is the very first prototype crash tested system we sent along for exploratory testing of designs and to start to understand the forces involved in restraining a system.
It really does look catastrophic and is if there was no restraint at all - however that is definitely not the case. It was a modular tank design with 850litres of water in it with screw-on lids. It did have a restraint system which weighed about 90kg and was very securely mounted into the van. It was a low-level perimeter frame mounting system (as favoured by many DIYers) along with restraint bars through the moulded centre of the tanks - these were all fixed with 16mm bolts through floor into spreader plates under the floor. We learned a lot from this 'failure' and used it to greatly improve subsequent designs and MIRA tests.
What happened in the accident-test was:
1. The tanks collapsed under the weight of the water (this was despite being tank standard 6mm thick polythene) - this was because despite feeling very strong the tank itself is flexible in a crash and without full height restraint at the front can move too far forward.
2. Due to the collapsing pressure of the water the lids were blown off and the tank ripped apart.
3. Then under the strain of this forward movement the restraints bolts and spreader plates (1/4 the size of the current ones) started moving forward and sliced through the floor pan like a knife through butter destroying several cross members as it slid through them.
4. The system had moved completely out of the cargo area, through the cab area and then the forward moving water ripped through the engine bay bulkhead.
At the time I was not very pleased with the end result ******************************/Smileys/classic/angry.gif - however as a learning tool it was invaluable and taught me a new respect for carrying such a concentrated (most of the vehicle's load in just a 1/6th of its load area) and fluid (as in its ability to change shape) load.
What we did learn has been incorporated into the current Grippamax systems:
Non-Modular increased strength tanks
Burst-proof lids
Low level tanks
Full 'honeycomb' baffling
Full height restraint system
T-Bar front and rear restraint bars with large bonded spreader plates
This is why i had a grippamax system fitted.
Fitting your own wydale tank in a steel frame through the chassis is not the same as grippamax system or a proper crash tested system. On the market there are several companies with crash tested systems and some perform better than others. The issue has and always will be the tanks used in DIY systems.
If you watch the video you will see the lids are screw type and the same as wydale tank designs.
This is taken from the horses mouth.
[media]
[/media]
The video you are referring to of the 'tank fail' is the very first prototype crash tested system we sent along for exploratory testing of designs and to start to understand the forces involved in restraining a system.
It really does look catastrophic and is if there was no restraint at all - however that is definitely not the case. It was a modular tank design with 850litres of water in it with screw-on lids. It did have a restraint system which weighed about 90kg and was very securely mounted into the van. It was a low-level perimeter frame mounting system (as favoured by many DIYers) along with restraint bars through the moulded centre of the tanks - these were all fixed with 16mm bolts through floor into spreader plates under the floor. We learned a lot from this 'failure' and used it to greatly improve subsequent designs and MIRA tests.
What happened in the accident-test was:
1. The tanks collapsed under the weight of the water (this was despite being tank standard 6mm thick polythene) - this was because despite feeling very strong the tank itself is flexible in a crash and without full height restraint at the front can move too far forward.
2. Due to the collapsing pressure of the water the lids were blown off and the tank ripped apart.
3. Then under the strain of this forward movement the restraints bolts and spreader plates (1/4 the size of the current ones) started moving forward and sliced through the floor pan like a knife through butter destroying several cross members as it slid through them.
4. The system had moved completely out of the cargo area, through the cab area and then the forward moving water ripped through the engine bay bulkhead.
At the time I was not very pleased with the end result ******************************/Smileys/classic/angry.gif - however as a learning tool it was invaluable and taught me a new respect for carrying such a concentrated (most of the vehicle's load in just a 1/6th of its load area) and fluid (as in its ability to change shape) load.
What we did learn has been incorporated into the current Grippamax systems:
Non-Modular increased strength tanks
Burst-proof lids
Low level tanks
Full 'honeycomb' baffling
Full height restraint system
T-Bar front and rear restraint bars with large bonded spreader plates
This is why i had a grippamax system fitted.
Fitting your own wydale tank in a steel frame through the chassis is not the same as grippamax system or a proper crash tested system. On the market there are several companies with crash tested systems and some perform better than others. The issue has and always will be the tanks used in DIY systems.
If you watch the video you will see the lids are screw type and the same as wydale tank designs.
