Yeah it is the RTF version. I just started it tonight and noticed that when I remove the glow driver the RPM drops a fair bit. I've heard that this could be to do with the amount of nitro in my fuel (its 5% as I was advised to run a bottle of this through it before I use a higher nitro fuel). I was told the other reason could be the glow plug driver but I'm using the one they sold me when I got the plane so it should be right.

I'd like to know what is the most likely cause and is this something most people experience when starting a new engine or using low nitro fuel?

Thanks guys.