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In one of the answers to the question which aircraft is the oldest in production, the Beechcraft Bonanza is mentioned. While reading the Wikipedia entry on this interesting plane, I noticed that there are some models with a V-shape tail and some with a more conventional tail.

What is the difference between the two designs?

Bonanza with V-tail Source: Wikipedia

and

Bonanza with conventional tail Source: Wikipedia

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V-tails have been fashionable in the Fourties and Fifties, and the claim was that they would cause less drag than an equally effective conventional tail. This has two reasons:

  1. Average chord length is longer, so the Reynolds number of the airflow is higher, causing relatively less friction drag.
  2. Instead of three surface-fuselage-joints, the V-tail has only two, so less interference drag is created.

Flight testing of V-tails showed only marginal advantages, and in damping they are less effective than a conventional tail which is dimensioned for the same control effectiveness. The control effectiveness of a control surface is proportional to the cosine of the V-angle, but the damping characteristics go down with the square of the cosine.

@nimbusgb mentions the tendency of the V-tailed Bonanza to fishtail: That is a consequence of too little lateral damping.

Also, when a combined elevator-rudder input is commanded, the V-tail will produce a very high deflection on one side, while the two commands will cancel out on the other side. This will reduce overall control power in cases where a combined elevator-rudder input is commanded over what is possible with a conventional tail.

Even the glider designers, who had enthusiastically tried out V-tails, have now returned to conventional tails (more precisely, T-tails) because the expected benefits did not materialize. And glider designers will try anything to improve the aerodynamic quality of their designs.

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V-tail production ceased in 1982. Possibly due to a perception that they were less safe than a conventional empennage.

  • The model 35 Bonanza series (1947-1982) had a V-tail
  • The model 36 Bonanza series (1968-present) had a conventional tail.

There was a self-serving faction in general aviation, though, that went on a crusade to demonize the V-tail because of the in-flight structural failures.

Grist for the mill was the fact that Bonanzas with regular tails seldom had structural failures. They did have just as many loss of control accidents. The difference was they were in one piece a millisecond before becoming thousands of pieces after a collision with the ground. The V-tails didn’t make it to the ground in one piece,

From What was wrong with V-tail Bonanza pilots?

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    $\begingroup$ and no doubt "rationalising the product line" also played a part. Why produce 2 effectively identical models, the only real difference being the shape of the tail plane? (and with one of them having a bad rep as accident prone, the choice which to stop making becomes easy). $\endgroup$ – jwenting Nov 6 '14 at 8:36
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The technical stuff in other answers is right. The other difference is that the V-tailed Bonanza's tended to 'fishtail' slightly in the cruise.

If I recall correctly, V-tails are not as spin resistant as conventional tails.

My dad flew a Standard Austria for a time (early V-tail sailplane) and it was very definitely prohibited from intentional spinning. Dad tried it once and told me it took about three turns before it would recover.

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    $\begingroup$ Ahh - Standard Austria! Maybe you shouldn't spin it, but it definitely was well suited for loopings. At the occasion of the first flight with the finished prototype of the Standard Austria, the pilot started to fly loops. After the third, he asked the designer over the radio: "Notice anything?" - "Yes, you're climbing" was his answer. Thereupon the pilot replied: "That's how you can climb in thermals, too!". $\endgroup$ – Peter Kämpf Nov 7 '14 at 17:47
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    $\begingroup$ I think you're being too kind in describing the V-tailed Bonanza's tendency to fishtail as 'slightly'. I'd up that a couple of notches, and in turbulence it was just plain unreasonable in my opinion. $\endgroup$ – Terry Aug 20 '15 at 17:15
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    $\begingroup$ V-tails DO NOT fishtail any more than the short body Bonanza 33. The 36 doesn't fishtail simply because it is longer. It is the short coupled tails on the 33 and 35 that cause the fishtail, not the configuration of the tail. $\endgroup$ – acpilot Oct 14 '15 at 1:39

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