Fiber reinforced synthetic resin composites suitable for use e.g. in aerofoil blades for compressors, turbines and the like in which the fibers are carbonized fibers and the resin is the product of curing an isocyanate terminated prepolymer obtained by a reacting a polyisocyanate with a polyol at least one of which contains a cyclic group in a chain between two functional (i.e. hydroxyl or isocyanate) groups, and has a heat distortion temperature of at least 50* C., and the fibers form from 20 to 75 percent by weight of the composite.