Side impact honeycomb

[paul jacobs]

Some of you may know that in addition to my Seven, I am also the owner of a Morgan Three Wheeler. This car does not have any side impact aluminium honeycomb in the side panels, even though there appears to be room for it, however, as I've never had the side panels off my Seven, I don't know how Caterham keep the panels in a Seven, is it just loose and sandwiched between outer and inner panels or are there any fixings of any kind?

 

I'm seriously thinking of installing some into my Three Wheeler for peace of mind, anyone got any thoughts on whether that would be good or bad?

[6speedmanual]

Sandwiched.

Potentially good idea.

 

Peter

[elie boone]

4 dots of Sikaflex will do the job nicely.

[Nigel Riches]

Hi Paul, I added the honeycomb several years back when the inner panels where removed.

 

As Elie says, silicone adhesive will do the trick, be sure to thoroughly degrease first.

 

There may be some benefit in applying the adhesive to the panel you remove, as then the honeycomb could be removed with the panel later, if needed.

 

Nigel.

 

P.S. Still working on Zetec install , most problems of my own making 🙆🏻

[tiddy1]

to be honest you may as well fill the gap with toilet paper for all the good it will do.

 

Yes it may help prevent a sharp pokey thing from penetrating, but without being properly bonded to the to the outer and inner skins its next to useless

[Golf Juliet Tango]

Quoting elie boone: 

4 dots of Sikaflex will do the job nicely.

Other suitable adhesives are available, see this thread

[ECR]

Never really understood the use of honeycomb panels in a Caterham. The idea presumably is to absorb impact energy, but the honeycomb can only do that by collapsing slowly. It won't collapse properly unless it has a rigid surface behind it and the panels in a Caterham are hardly that .....

If it's there to give torsional rigidity then it does need bonding properly

[andy couchman]

AIUI the original idea came from Reynard and they used it to improve safety on a (wealthy) customer's race car. Caterham adopted the idea and have used it ever since.

 

Not sure about securing it. It seems very simple (Sikaflex again...) but surely Caterham/Reynard would have done that if they thought it necessary? Any fixing is likely to be not very strong and isn't the purpose of the honeycomb just to absorb energy and disperse it over a very wide are (the honeycomb). The honeycomb is a 'tight' fit within the tubes and unless it bursts out through the ali skinning it will have done its job, There must have been enough race crashes by now to prove or disprove its value and to show what actually happens?

 

Years ago I did a cheaper version by using solid cavity wall insulation (polystyrene) in the door sides of my 1988 car. Never had to test it in anger but the theory was the same - effectively creating a sandwich and a big area to disperse any energy. I still use the same behind the fuel tank, again to provide a bit of inexpensive and very light protection.

 

Any race folk have evidence of how honeycomb has held up in practice?

 

Andy

[6speedmanual]

It is to prevent bending inwards of the side rails and to some extent anti-penetration in the event of a side impact. It is very resistant to bending in itself and also via the skins and rivets spreads the load of a side impact (from say a lamp post) along the length of the space frame tubes rather than them bending inwards at the point of contact.

It is held in place between the skins and the load is taken by the rivets on the skins.

Main benefit is to reduce chance of driver entrapment by a big ? shape curve in the upper side rail of the space frame.

Not crumple/collapse energy absorption, not for torsional rigidity.

 

Peter

[6speedmanual]

Back to Paul's original question:

The effectiveness depends on whether is can usefully be accommodated between inner and out skins, in a place where it would usefully reduce severity of collapse around the driver which could cause entrapment.

In principle it could work if the Mog is double skinned.

 

Peter

[ECR]

Thanks Peter

 

Than makes some sense. I've only seen it used as an energy absorber before

[paul jacobs]

Some good info, thanks all. The Mog has an inner panel which is mainly cosmetic I think, but it could be replaced with aluminium, like a Seven, bonded and riveted to the upper and lower chassis tubes. I will investigate further...........