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The much maligned Max 8 and the Buckeye Navy trainer. What could they have in common?

Both would want static stability (trimmable speed stable approach) for landings. Both would want maximum fuel efficiency for maximum range.

Engine up thrust would require less tail down trim for balancing forward CG. Ideally, this could be optimized for cruise, so, at cruise airspeed and power, no tail down force is required, just like a plane with the CG back. Much less drag.

The advantage is, once you drop out of cruise (less power), you now have a more staticly stable (read can be trimmed for one speed), making approaches to landing much easier. Helpful for carriers and busy airports alike.

Is this such a bad design after all?

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    $\begingroup$ Bad for what purpose? Bad for any purpose, or bad for the purpose of "being a 737, just with brand new composites" (or some such)? $\endgroup$ – a CVn Apr 23 at 14:35
  • $\begingroup$ Well, if they get full power on/slow flight squared away I'd have to say awfully good for a 737! $\endgroup$ – Robert DiGiovanni Apr 23 at 15:14
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    $\begingroup$ Problem is if the thrust line effects are too strong it becomes a pain, especially if hand flying an approach and thrust changes require constant retrimming. In any case the problem on the Max as I understand it isn't so much the thrust line effects but that the lift from the larger nacelles, moved forward, moved the aerodynamic neutral point forward, having the same effect as moving the CG limit aft. $\endgroup$ – John K Apr 23 at 18:10
  • $\begingroup$ Who said the Buckeye is much maligned?!! I had a blast flying it, and so did everyone else I know. As with every airplane you just need to learn the little idiosyncracies... $\endgroup$ – Michael Hall Apr 23 at 21:20
  • $\begingroup$ Didn't say it was. Actually (since Navy aircraft designs are quite outstanding) I was trying to show this may be be a good idea if properly done. All the diagrams I've ever seen never showed thrust angle as a means of improving cruise efficiency. I also see a little 4FD in the Navy F35C. $\endgroup$ – Robert DiGiovanni Apr 23 at 21:54

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