The Su-57 prototype has two tandem main internal weapon bays each approximately long and wide and two small triangular section weapon bays that protrude under the fuselage near the wing root. Internal carriage of weapons preserves the aircraft's stealth and significantly reduces aerodynamic drag, thus preserving kinematic performance compared to performance with external stores. The Su-57's high cruising speed is expected to substantially increase weapon effectiveness compared to its predecessors. Vympel is developing two ejection launchers for the main bays: the UVKU-50L for missiles weighing up to and the UVKU-50U for ordnance weighing up to .