Carbon prop life?

[Mike Biddle]

Do carbon props deteriorate over time? Is there a way to get them tested/looked at/X rayed or something? Where to get such a service? Note original supplier not interested, not replying to mails/calls etc.

My car is being put back together after being rear ended earlier this year and the question has arisen.

 

[Jonathan Kay]

We have an expert technical X-rayist member...

But I think you're going to get very conservative answers with or without images because no-one has done enough tests to know, and the effects of failure could be quite nasty.

Jonathan

[David Brown]

Mike, not sure that X ray is the way to go. Believe ultra sound is better (maternity rather than orthopedics) but think it's all in the interpretation of the results. Try Googleing NDT of carbonfibre.

[Golf Juliet Tango]

I doubt enough examples have been in use for long enough to tell.

[Mike Biddle]

Thanks for the input.

Mike.

[Doug phillips]

Ultra sound is the way to go, when I was at Red Bull they were checking a front wing using it. It is the only way to look for fractures, I don't know of anybody who offer it as a service.

[Geoff Brown]

With my (limited) experience of Carbon & Kevlar in the aircraft industry any liklehood of damage must be inspected visually then by X-Ray & ultrasound.

The properties of the materials have a habit of hiding the true extent of the damage especially in the case of stone or bird impact. Just like icebergs what you can see is just a small percentage of the problem. From a simple impact point the damage spreads subterranean like through the sub-strate out of visual range.

The usual course of action is if it is a panel throw it away if not then a lot of repair schemes actually advocate repairing with aluminium.

With an item like a composite prop shaft that is under a lot of torque/twisting moment that has been subject to horizontal force as well (back ender) then minute inspection is advisable to determine IF there is any damage or the on-set of a failure mode.

To be honest the easiest & safest course of action is to scrap the shaft.

I know...its easy for me to say that but your safety is paramount.

 

[Nigel Riches]

If in doubt, throw it out, err on the side of caution, as said earlier, damage obvious at one place is a pre-cursor for deeper and extensive damage, not obvious to the human eye. 

Not a good scene to have the prop shaft let go. 

N. D. T.  On composite material like this may become more widely available, as aircraft manufacturers adopt these construction techniques into their structures. 

Regards, Nigel. 

 

[Mike Biddle]

No marks on the prop, and no witness marks on the front end to indicate contact with tail housing which would probably have happened if it was shoved forward, which I don't believe it was, De Dion tube is fine, as are radius arms and A frame, the impact was only on offside rear wing/wheel.

My question was prompted by the fact that it was out of the car and there was an opportunity to get it checked for fatigue.

Thanks to all contributors. Mike.