Steve 76 - you may not have a choice, but the S76C+ and S76C++ will usually give you a better disposable load and similar Ground Level Cat A Vertical helipad MTOW (11,00lbs) subject to WAT limit corrections. The S76B is a very good machine, but she is relatively heavy and burns more fuel per hour than the C+ and C++. (800 plays 710 from memory). Mind you those sweet PT-6's run like Chevy V8's. Those RFM references kindly mentioned by Sanus will point you in the right direction. Good luck !