Simplify the following text for a Grade 13 native English-speaking person.
Original: Using this biplane model , Chatterjee was able to calculate possible methods of gliding , and determined that Microraptor most likely employed a phugoid style of gliding : launching itself from a perch , the animal would have swooped downward in a deep U-shaped curve and then lifted again to land on another tree .
Simplified: Using this biplane model , he calculated possible methods of gliding , and determined that Microraptor most likely launched itself from a perch , swooped downward in a deep ` U ' shaped curve and then lifted again to land on another tree .