Resumee:

The Spit has a turn radius of 700 ft (about 215m) and the 109 slightly below 900 ft (275 m). The turn rate is at medium and high speed similar (slight advantage for spit at medium speed, tendency vice-versa for high speed). Good advantage for spit at low speed. Altitude loss higher for 109 during full circle (nearly 0 for spit at medium speed, 5° for 109 at medium speed)

Does not feel that way in game ...