Barnaby Wainfan - 7 Sins of Aircraft Design

[Hydroman]

The advent of LO/VLO aircraft has opened up the rule book. You need a very stealthy platform, you more than likely will have an unstable configuration. This gets you into F-117-type, flying wing-type, J-50, J-36, X-47A (more than likely F-47 and F/A-XX) blended delta wing-type, tailless configurations. This also now drive the types of flight surfaces required; v-tails, elevons, split-rudders, upper/lower surface in-laids, knife-edge speed brakes (i.e. RQ-170, Horten Flying Wings, Northrop N-1M Flying Wing), canted canards, etc, will require FBW control whether servohydraulic, electro-hydrostatic or electromechanical. Electromechanical not likely for a manned aircraft currently but for unmanned, yes. Tacit Blue was very unstable in all 3-axis and required a quadraplex FBW FCAS. So I don't think in current times there are really any "design sins" anymore just new possibilities.

 

[Scott Kenny]

Tacit Blue was very unstable in all 3-axis and required a quadraplex FBW FCAS. So I don't think in current times there are really any "design sins" anymore just new possibilities.

That's surprising, it looked to be conventionally stable. At least not any more unstable than a V-tail Bonanza.

 

[Hydroman]

That's surprising, it looked to be conventionally stable. At least not any more unstable than a V-tail Bonanza.

Tacit Blue very unstable.

 

[Cancerman]

I worked on it in the wind tunnel. It had it's challenges.