What does it take to get a commercial helicopter license?

Will I need to start training all over again at a helicopter school, or will I be able to go right into commercial training?

You can go straight for a commercial add-on in helicopters. You will have to meet the aeronautical experience requirements listed in 61.129(c) here:

http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ec...

You will have already met some of the requirements with your fixed-wing experience, such as 150 hours of flight time, and 100 hours in powered aircraft. But, the helicopter is a completely different machine and will take a lot of getting used to before you can meet the practical test standards. The regs state "50 hours in helicopters", but for the average person training at the average pace, I would expect 80-100 hours in helicopters before being ready to take the commercial checkride. It could be more or less depending on your proficiency and how often you can fly.

Is there an extensive ground school for this as well, or will I be able to concentrate on getting hours?

You will not need to take a written test, so that will be done. Furthermore, certain knowledge areas such as weather, navigation, radio communications, and so on will already be familiar to you. You will need instruction in aircraft systems, aerodynamics specific to helicopters, emergencies, flight controls, some regulations, helicopter performance, etc. So yes, you will need significant ground instruction, but no, you will not need a fully fledged ground course from scratch.

You can search for helicopter schools in your area through these sites.

http://www.bestaviation.net/helicopter_schools/

http://www.flightschoollist.com/helicopterschools....

For countries other than the US, you will have to find their regulations concerning add-ons, but it should be similar.

Good luck!

I am not positive about the first part, so I won't answer that. BUT, there is a ton of ground school. To get your instrument ratings and CPL/H you'll have to keep your nose in the books a good amount of the time, but you should be used to that by then. Helicopters are in no way fixed-wing. It's harder to go from a fixed-wing to a helo then a helo to a fixed-wing.

This is a Canadian website you should look at:

http://www.ebhelicopters.com/eb/flight-training/in...

If you live in the US, the conversion training will probably be somewhat similar.

Good Luck!