Hi!
The first thing you should do is to check if the fuel is coming out from the tank! Just fill it up and see if it comes out in the fuelline going to the carb....if it comes out real easy then connect the fuel line to the carb and try to start the engine!
No! do not put on any silencer extensions yet!!! It will increase backpressure and heat in the engine, which is not good! Later when you have the engine going maybe you could try it.

Some recommendations!
Use a 11x6 APC prop.
5-10% nitro
OS 8 or Enya 3 glowplug!
8-10oz fueltank.
Use a 12v 7-12A motorcycle batteri for starting and an automatic glowdriver to get the volt down to 2v for the glowplug.
1,2 v NiCads are useless...more or less anyway, only god for experienced flyers!

Regards!
Jan K
Sweden