ORIGINAL: All Thumbs
I know that .049's can have a piercing scream and I don't know if this little engine would fall in that category.
Yes it will. Dont have one myself but have seen one. In Db terms not loud, quiter than a 46 FX, but does scream, as all small engines do to an extent. An exhaust deflector helps a lot.
If you plan to fly with guys who only fly electric, I would ask them first if it is ok or not. If not, see if they will help you get an electric set up. If they don't help, probably not worth joining them anyway.