Flight into icing conditions introduces the risk of ice accretion to helicopter rotors. To understand and avoid the dangers related to rotor icing, test facilities such as the NASA Glenn Icing Research Tunnel have been developed. Due to the confined test section size of most current icing test facilities, an icing test on a full-chord helicopter rotor blade is not possible. To fulfill the research need of a novel full-scale-chord rotor icing test facility, the Adverse Environment Rotor Test Stand (AERTS) was designed and constructed at the Vertical Lift Research Center of Excellence, at the Pennsylvania State University. This book gives a comprehensive review of the current aircraft icing research. Ice accretion experiments were conducted to validate ice shape reproduction capabilities of this facility. Classical ice scaling methods were introduced and implemented to ensure experimental ice shape reproduction for varying chord-size blades. The validity of applying scaling laws to low-thrusting rotors was demonstrated. The comprehensive aircraft icing database provided in this book can be applied widely to the aircraft design and testing procedures.