air1jw1212.
>I wanted to know because I'm a Physics A-level student and for my investigation I intend to look at the net force produced for a PA28 to reach its rotation speed. Before Christmas however, I need to do a pilot experiment. I'm doing coefficients of friction for different rubbers...hence the reason I need to know the rubber name! <
Good luck with the dissertation. I was in the business some forty years ago and suggest that the subject you're dealing with can be quite complicated.
As many of the previous replies have offered, there are so many factors involved.
First of all, an aircraft tyre is designed to take impact before wear.
Secondly, it must be oil/fuel resistant. Hence use of neoprene or butane rubbers.(synthetics)
Thirdly, because a tyre flexes, it produces heat of its own besides heat produced by outside influences eg. hot sun, hot runways, heavy aircraft/ long takeoff runs, brake heat transfer etc.
Another major consideration is the total weight of the actual tyres.
Heat is the BIG problem as this will cause rapid deterioration of the tyre's ability to perform its job, both in frictional properties ie. braking, and in its own inherent distortion resistance/carcase failure.
Ply ratings relate to the fabric content of a tyre and are based on equivalent strength cotton fabric not the actual number of synthetic fabric plies in the tyre. Thus there are less layers of fabric than the rating suggests - another way of reducing the internal heat build up.
Friction coefficients are paramount with aircraft tyres and these are enabled to varying degrees by the 'formula' that the compounder develops.
He is the rubber technologist, usually a guy of degree level, who decides how much carbon black, antioxident, filler, liquid components etc. are milled into the masticated raw base rubber to produce the physical properties he needs to fulfil the tyre requirement..
As suggested, you should get in touch with the major manufacturers, Dunlop, Goodyear, Firestone, Michelin, Bridgestone. They will obviously not divulge specific compound data but should be able to help with basic aero tyre construction, and particularly physical and performance testing. Think of the problems with 1) Concorde ( High ground speeds) and 2)Airbus A380 (Huge weight problems) for example.
Just as a matter of interest, did you know that a large number of aircraft run on remoulds, purely an indication of wear in relation to carcase life !?
Rgds, Sleeve.
PS. Pls,guys, don't get me involved in any further discussion on tyre design queries. It would take a book !
