Radials vs Rotaries

[Elfen]

I was looking over some engines in the Jane's Handbook of WW1 engines, and was surprized to see that Radial Engines were around since the start of the war. Being able to give more horsepower than an equal pistioned rotary engine like the Gnome, why was it that the rotaries were chosen over the radials?

I can see in situations, where a radial would be the better options: no more camel bites for one.

[Ransom E. Olds]

The radial engine actually predates the rotary, but the real problem with early radials lay in constructing one powerful enough and light enough to supplant the rotary. The only radial used in operational aircraft in the Great War was the Salmson, and it required water cooling in order to avoid overheating problems. Smaller Anzani radials were used in training aircraft, but they were not efficient enough for other use. Only in the 1920s were Bristol, Lawrance, Wright and others able to devise aircooled radials that retained the weight advantages possible with that layout without incurring fatal overheating problems. Ransom

[jumpinjan]

Radials have adverse reciprocating dynamic balance problems to overcome and it was not well understood; Rotaries didn't have those problems, they were easy to balance out.
They didn't understand & didn't apply effective air-cooling designs. Rotaries again were the answer.
They relied on flywheels to smooth out the power pulses to save the crankshaft. Rotaries again were the answer.
Rotaries were lighter, because they were simpler in design and had excellent power-to-weight ratio.