Speculating and guessing sure can mislead a reader here, which seems to be common on these forums.
Cold bending wire is not the best way.
It's clearly an example of doing something faster and cheaper. Get an educated answer that correctly supports the proper method in heat bending and temper treating steel wire, I quote: (http://en.wikipedia.org/wiki/Blacksmith#Bending
Other than to increase its malleability, another reason for heating the metal is for heat treatment purposes. The metal can be hardened, tempered, normalized, annealed, case hardened, and subjected to other processes that change the crystalline structure of the steel to give it specific characteristics required for different uses. Only steel, not iron, can be heat treated, and generally speaking, the higher the carbon content of the steel, the more it can be hardened.
When working with steels, a blacksmith will heat the metal and then quench it in various liquids such as water or oil. The purpose of quenching is to produce rapid cooling to generate specific microstructures in the metal. A quench from a bright red or orange heat generally results in steel that is hard and brittle, so a second process, called tempering, is usually done to increase the toughness of the piece and reduce its hardness.
Tempering involves heating the material to a specific temperature (lower than red heat) usually called "critical temperature" and judged for common steel by the temperature at which the metal looses its magnetic attraction. Sometimes it is quenched again after this heat.
With most tool steels, the degree of temper achieved can be gauged by the appearance of a colored oxidation tint on the metal surface. Different uses require different hardness and toughness combinations, and so receive different degrees of temper. It is possible to temper different parts of an object to different levels of hardness.
I don't know where those who disagree are getting their expert information. But it's clearly inconsistent with what people dealing in metals would practice, in a quality environment. [X(] It's not what seasoned builders would agree with to cold bend, as you can find them above.
While I'm ranting, read about all the Phoenix ARFs losing elevators on the first flight, or the Dazzler breaking in two on landings and you'll suddenly realize the garbage out there isn't built by any standard but giving you a kit for under $100.00. These include the cold bent landing gears. I shuddered just now. If it runs down the runway once, they feel they served your needs completely. The cheap hardware will cost you hundreds in good RC parts you will crash with it. Or the lousy labor of poorly pinning and gluing hinges, non-reinforced firewalls, etc. Reporting failures after you totalled your RC investment into the ground, are ignored too.
Bending cold certainly does
cause stress cracks regardless of the radius, and it's confirmed. Heat Bending with tempering is the better way to do it.