[1][2] When the U 7 first appeared in 1924 it was powered by a 13 kW (18 hp) Douglas 500 cm3 (31 cu in) flat twin, mounted in a squared-off cowling with its cylinders exposed for cooling.

[2] The Kolibri's tail was conventional, with a trapezoidal plan tailplane and elevators mounted on top of the fuselage and with a quadrantal fin and a rounded rudder that reached down to the keel.

[2] It had a very simple, fixed, tailskid undercarriage with the mainwheels on a short single axle held just below the fuselage underside, making the track narrow.

[4] The weather was not good, with high winds, and the Kolibri, flown by Udet, was the only one of three powered aircraft to complete the 80 km (50 mi; 43 nmi) round trip from the Wasserkuppe to Kissingen and back, thus winning first prize.

[8][9] In October 1924 Udet, again starting from the Wasserkuppe, flew the U 7 for 4 hr 39 min, an unofficial record for very light aircraft.