Originally Posted by
JohnDixson
TT: nothing to do with the canted tail. If you check the 53D for instance, you get similar results.
Re your post 56, the point is quite true, but somewhat mitigated by the fact that the two tandems in the US military inventory history, the CH-21 and CH-47, were/are both cargo helicopters, thus not expected to have a mission agility capability such as the OH-58 or ( wistfully ) the RAH-66 Comanche.Flew both the 21 and 47 at the test board at FT Rucker 1963-65, and both had more than adequate directional control. Before someone jumps me, I was addressing flight, and leaving the taxiing techniques discussion to another day, but even there a bit of finesse went a long way.
John - thanks for the referral to 53D cig range. I’m beginning to suspect a tandem pitch-control limitation on cg. Note that I wasn’t dinging tandem directional control but its directional stability. Another interesting facet of tandem performance was that confined areas were best departed sideways to get the most out of both rotors in the process.