Hi Srivatsa,
A Glider is an aircraft without an engine/motor.
It has to be launched to/at a height (hilltop, bungee, winch, auto tow, aerotow) from where it glides down.
A Sailplane is a Glider efficient enough to gain height after launch, using updrafts from thermals, slope lift, wave lift etc.
The RC Glider duration record is over 36 hours.
The RC Glider speed record is over 500mph.
No engine or motor!
Nowadays most model glider flyers prefer an electric motor equipped one, as it simplifies the launch.
Once at the desired height, the motor is turned off, and the rest of the flight flown without power.
There are alternatives, though.
If you are interested, I’ll post links to some of my threads on this forum, that have relevant videos.
Mr Reddy’s post/video is of a DLG, which is a special case. Usually under ~300gms.
That Salto is 1.8 kg.
If you are thinking of buying it, my advice is please don’t. For 2 reasons.
1. You may not have the equipment to launch it
2. You may not have enough space to land it!
Incidentally, I’ve seen only winch launches so far (full size)
IITK may be doing aerotows. They have powered gliders too now.
Regards