Helimark,. .The fan power varies just like the power to a tail rotor, so there is no one number. Also, the coanda slots are quite efficient, so when the downwash is perfectly aligned with the tailcone, the Notar is not toobad on power. But if the wind is slightly from the tail, the coanda is of almost no use. The original Notar experiments found no yaw control when the wind was 6 knots from the tail, so the can was added to create a tip jet.. .. .One funny thing about power losses is that hover charts in the flight manual are determined in still air, when the main rotor power needs are highest, but when the coanda is most efficient. With any wind or maneuvering, the tip jet becomes the anti-torque device to a fair degree, so the engine power needed goes up, unlike a conventional helo.. .. .For most helos, 1 horsepower lifts about 6 pounds in a hover, so if the Notar eats 25 horsepower more than a tail rotor, that costs 150 pounds of payload. A common tail rotor uses about 5 or 6% of the main rotor power, so a 400 HP helo uses 20 to 24 Horsepower in its tail rotor in a steady hover. If a Notar uses twice that (I think that is a fair estimate), it can lose about 1 passenger as compared to an otherwise identical tail rotor equipped helo.. .. .The protection of a notar is legendary when compared to a tail rotor. If the can in back is bent or jammed by a ground contact, you can get a stuck pedal, but the strike that jams the can would certainly toss a tail rotor into the next county.