Thrust reversal
SNS3Guppy. If you believe that the contribution made by reversing the gas flow and/or fan discharge is such a minor one in the reduction of forward speed, why is it that so much work goes into the design of the reversal system, whether it be clam shell, bucket or blocker doors? Further, if simply removing the thrust would lead to the desired speed reduction, why are the engines accelerated to the relatively high thrust setting attained at Maximum Reverse? Also, it is common for the thrust to be redirected forward by as much as 45 degrees. Just look at the cascade vanes on a RB211 or JT3D, or the buckets on a aircraft so equipped.