As you know, aeromodelling motor “rainbow-7)” is a typical “Kalinka”. But a few additional parts easily turn it into a compression engine with a displacement of 7.0 cm3.
Somebody will ask: “why? “Rainbow” is so good and serves many modelers”. However, remember that the rules of the competitions held among students, prohibited the use of glow motors, as part of their fuel is comprised of highly toxic methyl alcohol. And guys want to build a “real” pilotage or copies, for which even the best diesel engines volume of 2.5 cm3, commercially available, weak.
In addition, during the transition to compression version is almost 2 times reduces the specific fuel consumption. No wonder some foreign firms established production of special head that allows to switch the engine performance even at 10.0 cm3 of diesel fuel. This transition is justified: at the same power, the motor does not need expensive and scarce alcohol, is simultaneously reduced and the fuel consumption so that is not a sin to think about the record attempts on the range or the duration of the flight model.
To rework the “Rainbow” will need to make only four parts, you can make them in any school workshop.