A "recognised aeroplane" can be:
A VH- registered, powered aircraft.
An aircraft on the register of another country.
An ultralight, provided it is of the 3-axis control type. This means it has a yoke or control stick like VH planes, but cant be weight-shift controlled. Powered parachutes are not OK, Jabirus or Gazelles are fine. Basically as long as it has an engine that needs to be on, and its controlled in the same sense as heavier aircraft, then you can count the time.
I'm doing the same thing, hour building for my CPL right now. I have N-registered aircraft and ultralight time in my logbook, and if all goes to plan some ZK- time logged later this year too.