Comparable aircraft, such as the Boeing B-29 Superfortress with a wing loading of 337 kg/m2 (69 lb/sq ft), the redesigned He 277 at 334.6 kg/m2 (68.5 lb/sq ft) and the Ju 390 at 209 kg/m2 (43 lb/sq ft) had lower wing loadings. The relatively high wing loading caused poor climb performance, loss of manoeuvrability, stability and high take-off and landing speeds. The first prototype was not fitted with weapons or armour but the following two prototypes, the Me 264 V2 and V3 had armour for the engines, crew and gun positions.