From searching, 40'ish mph on the road with a powertap is about 1200-1500watts.

40mph on a KK road machine using the equation they provide comes out to 1469watts.

I wouldnt' ever want to compare KK estimated watts to actual watts, but it seems like its in the ballpark. Useful for comparing against yourself, and possibly others on road machines as well.

I'll have to see how fast I can get up to on mine. 40mph on it sounds pretty brutal.