Free flight : Power models
Power models?
The term 'power models' refers to those using internal combustion engines. These might be tame; sport or scale models flying slowly to a modest height. In contrast, competition models spiral upwards, gaining hundreds of feet in altitude within a few seconds.
Scale models
Small diesel engines are the classic propulsion for scale models.
They are still widely used, especially for larger models.
Sport power
There is a rare thrill in seeing an own-built model come alive with a diesel motor and fly well. Reasonably uncommon now, they used to be THE models to build. In a large area and if fitted with trackers and dethermalisers , they can be allowed to climb steeply, as intended in the 1950s.
Competition Power models
The aim of these models is to gain the maximum altitude from a limited engine run (4 seconds). They climb almost vertically then transition to a glide once the engine cuts. They need careful trimming to deal with the large difference in speed. Some models employ flight surface adjustments to improve performance. Image temporary from BMFA.