In part because of its advances in technology and a top speed greater than existing Navy aircraft, numerous technical problems had to be solved before the Corsair entered service. Carrier suitability was a major development issue, prompting changes to the main landing gear, tail wheel, and tailhook. Early F4U-1s had difficulty recovering from developed spins, since the inverted gull wing's shape interfered with elevator authority. It was also found that the Corsair's right wing could stall and drop rapidly and without warning during slow carrier landings. In addition, if the throttle were suddenly advanced (for example, during an aborted landing) the left wing could stall and drop so quickly that the fighter could flip over with the rapid increase in power. These potentially lethal characteristics were later solved through the addition of a small, -long stall strip to the leading edge of the outer right wing, just outboard of the gun ports. This allowed the right wing to stall at the same time as the left.