Spares for controlled models are the stock you remember at the worst possible moment — after a crash, on a free Saturday, with the wind finally right. This group covers small drive and mechanical components, among them helicopter tail rotor parts, and other items that wear out in ordinary use. Buying them with the model is the sensible habit: one small part often decides whether an afternoon ends in flying or in rummaging through a box.
When choosing, always check which model a part was made for — shaft diameters, blade lengths and mounting differ between sizes, and a universal substitute is the exception rather than the rule. It is worth keeping one set of whatever breaks most often at home: rotors, blades, small couplings and covers. For the replacement itself, modelling tools with screwdrivers and side cutters are enough. Look for parts by the type of machine, for example under RC helicopters, and find the whole branch in RC models and chuck gliders.
