That is an oldtimer free flight plane wíth a diesel engine and the plane should be returned to its owner.
Did you not find a telephone number and a name on it?
The plane was obviously started up wind from where it landed.
If you have not found the owner, pleast put up a note in your local market where the plane can be found.
The plane should not be converted to RC as it flyes best as it is.
The motor has a time limit of maximun 30 seconds (the small tank) and spirals the plane to hight.
The model starts to soar and tries to find a thermal to keep it up as long as possible.
There is normally a "fuse" that releases the stabilizer after 2 or 3 minutes depending on the local rules.
The plane will decend fast after it has "lost" its stabilizer.
Your plane has not "fused" and might have been flying for a long time.
Do you have any large grass field up wind from where the plane landed?
As you can see, the motor is very close to the wing and the CoG is behind what is normal for a RC plane.
The stabilizer is active in lifting this plane making it designed for 2 modes : Going up with motor and soaring with the motor stopped. Those planes are hard to get flying well with RC.
Price? Lots of hours if the plane is "perfect" but your video does not show a lot of "finesse". The motor is only of use if you can find the correct fuel.
The video did not show the motor very well - it might be a frog or ed.
The decal stands for
SOCIETY OF MODEL AERONAUTICAL ENGINEERS
This is a subset of the
British Model Flying Association and probaly a member of
SAM
