Messerschmitt AG.
Speed influence of the
Me 109 G landing gear doors
 Test Report
109 16 L 42
 Date 15.8.42
 Copy    2
 Dept. Flight Test

Reason:With the serially produced Behr-laminated wood landing gear doors, developed as a result of the tests carried out April last year, a functional test was to be carried out on the ground and in flight and the influence on speed was to be measured.

Repeated raising and lowering in rigged up condition and in flight; one test flight to be flown with and without landing gear doors installed.

Results:After adjusting an imprecision in the installation, the kinematics functioned properly. Neither were the landing gear doors torn off at 650 km/h indicated airspeed, nor did any difficulties appear during retraction of the landing gear within the permissible speeds, even with the aircraft in a light slip. An estimated extra 8 - 10 seconds is needed for lowering the landing gear than in the case without landing gear doors. The increase in speed with the landing gear doors installed is 8 km / h (+ - 3 km / h).

Since the tested landing gear door is still not in its final form (it should be replaced by a 5 mm thinner cover and thereafter with a more bulged shape since the clearance of the intended larger landing gear appears uncertain with the current one used), a new trial will have to be conducted with that one.

Since the bulge on the upper wing (to accommodate the larger landing gear) is installed mirrored on the test vehicle, the correction of this error must be arranged for future serial production.

Aircraft:Me 109 G-1 Werk Nr. 14003 VJ + WC

Engine: DB 605 A Werk Nr. 76172

Operating hours at the beginning of the tests: 8 h 15'

Operating hours at the end of the tests: : 9 h 22'

Propeller:VDM 3-blade Serial Nr. 13.15290

Landing gear
Drawing Nr. A 16207

Weight:3016 kg (23 kg Ballast installed for other measurements.)

Test days:12.8.42, 13.8.42, 14.8.42

Condition:109 G-1 series, single wire antenna, pressurized cabin. Radiator closed during the measurements (inlet 55 mm)

After the retraction mechanism checked out during testing on the rig and in the 1st in flight check, the rear locking bolt (visible in photo 1) of the right cover was pressed against the locking hook in a way, that it came to rest at the highest point without gliding along the slope. As a result, the cover was squeezed off at the nearest attachment point (chalk mark photo 1). Photo 2: Tear position viewed from outer wings. After correcting the defect by moving the clevis forward, the extension, retraction and the lock worked properly . After the test flight with the landing gear doors installed, they were removed within 10 minutes by loosening 7 screws, so that the mounting flanges were within the otherwise covered landing gear area compartment. Photo 3: mounting flanges for inner landing gear covers in the extended position.

Results:Speeds not corrected at
B = 726mm Hg: t = 20° ; n = 2600 U/min; P2 = 181; p4 = 129;

With landing gear doors:      528 km/h
Without landing gear doors: 520 km/h

  Messerschmitt AG. Flugerprobung.          Gruppe: Leistungen           Bearbeiter: Karstedt

Geschwindigkeitseinfluß der Fahrwerkrestabdeckung 109 G (pdf)

WWII Aircraft Performance   Me 109 G Flight Tests