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Lockheed 1049E empennage design

Photo.

What is the reason for making the empennage of this Lockheed L-1049E Super Constellation's design look so complicated with two vertical horizontal stabilizers? In my understanding, the more components installed, the more the weight of the airplane will be, and as a result will put more load on the engines, especially if there will be more actuators required. Do all the horizontal stabilizers have controllable surfaces? What is the reason for making the horizontal and the vertical cross each other, and not attaching them at their tips (marked with yellow and green circle)?

Edit: I corrected the question on the body from with two additional horizontal stabilizers? to become with two additional vertical stabilizers? as supposed to be as I marked in the picture.

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    $\begingroup$ "... with two additional horizontal stabilizers?" - I'm guessing you mean vertical stabilizers? The airplane in the picture has three vertical (yaw) stabilizers, but only one horizontal (pitch) stabilizer. $\endgroup$
    – Tanner Swett
    Oct 7, 2019 at 13:16
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    $\begingroup$ Additional related question; "wouldn't the design of this tail have generated less interference drag if the vertical stabilizers had been placed at the very ends of the horizontal stabilizer, with no curved "tips" of the horizontal stabilizer extending outboard of the vertical stabilizers? (And note that the same question may be asked of the Lockheed P-8 Lightning.) Similarly, wouldn't it also have been beneficial to eliminate the middle vertical stabilizer and enlarge the outboard ones as needed?" $\endgroup$
    – quiet flyer
    Oct 7, 2019 at 13:52
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    $\begingroup$ They weren't affected by the Area Rule, but they were by the Rule of Cool. $\endgroup$
    – Harper - Reinstate Monica
    Oct 7, 2019 at 17:43
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    $\begingroup$ @TimberSwett, many thanks for your correction. I corrected it. Yes, it supposed to be vertical stabilizer. $\endgroup$
    – AirCraft Lover
    Oct 7, 2019 at 17:49
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    $\begingroup$ @quietflyer, that also my intention to put "complicated" on the title and marked both the extended part of the stabilizer, both the outboard horizontal stabilizer and the vertical stabilizer. I hope our friend will have the answer. Here is a clear picture the empennage of Antonov An-225, clearly shown it no horizontal extension from the ourboard vertical stabilizer, but yes it is there are extention to beneath the horizontal stabilizer. So, my question become more significant to be answered. $\endgroup$
    – AirCraft Lover
    Oct 7, 2019 at 18:07

2 Answers 2

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Complicated is a matter of opinion and I wont address that specifically since its somewhat subjective. But the core of the question is "why did the L-1049E have 3 tails" which is a legitimate question for this site.

The design was to allow the aircraft to fit in hangars of the time

A sleek fuselage, something like an elongated fish with smooth curves, featuring a circular cross-section, a snub nose, and a triple-fin tail. Triple tailfins were selected because a single tailfin would have been too tall to fit into typical hangars.

The L-1049E had tricycle style gear that was quite tall (for the time) and a standard single tail would have made the aircraft too large to fit into the hangars that most fields had.

The above link also discusses that for a particular Military version ("WV-1") of the aircraft the lower section of the tails were extended to compensate for a radome being mounted on the top. This came along only a year into the design and the subsequent builds may have been a hold over.

Weight as a result of the added rudders would not have been as much as you may expect since they were traditional fabric covered style surfaces

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    $\begingroup$ Well, an aerodynamic reason, in that the amount of fin/rudder area required dictated how tall a single tail would have been. Think B-17 or B-29 class -- but the B-17 was a tail dragger. Add tall tricycle gear, and that tail is much higher above ground. The military had to modify a lot of hangars for the B-29 -- commercial couldn't just throw money at the hangaring issue. $\endgroup$
    – Zeiss Ikon
    Oct 7, 2019 at 11:16
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    $\begingroup$ @ZeissIkon, The military had to modify a lot of hangars for the B-29 -- commercial couldn't just throw money at the hangaring issue. This is make sense. $\endgroup$
    – AirCraft Lover
    Oct 7, 2019 at 11:18
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    $\begingroup$ Ideally you would extend the vertical tail equally above and below the horizontal surface, which would allow the T junction to be a bit lighter since it doesn't have to absorb major bending into the base of the T. Problem is now the bottom of the vertical fin sticks down too much to clear the ground when rotating for takeoff or when landing. So you have to raise it and make the intersection beefy enough. Engineering is a Wack-A-Mole en.wikipedia.org/wiki/Whac-A-Mole game, where, when I whack the mole that pops up in this hole, it pops up in another hole and on and on it goes. $\endgroup$
    – John K
    Oct 7, 2019 at 12:26
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    $\begingroup$ @AirCraftLover Look up "shuttle carrier 747" and how it's tail is different from a regular 747. It's because the shuttle mounted on top disrupts center fin. An-225 was designed to carry Buran from beginning, that's why it has 2. I've read somewhere that the second unit was supposed to have usual tail with one big vertical stabilizer. Winglets are not comparable to a tail fin, they're not meant to carry loads. BTW, horizontal stabilizers on Super Constellation are "not controllable" at all. Only elevators and rudders move. You want stabilator, this is not. $\endgroup$
    – Agent_L
    Oct 7, 2019 at 19:21
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    $\begingroup$ All vertical fins had a controllable rudder as can be seen in this photo. -although that is actually a L-049, I think the rudder system is the same. $\endgroup$
    – TomMcW
    Oct 7, 2019 at 20:16
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Food for thought: perhaps the design of the Constellation's tail was inherited -- aesthetically if not engineering-wise-- from the Lockheed P-38 Lightning, where the position of the two vertical fins was selected to put them in the optimal position relative to the propwash from the two engines. Even on the P-38, it seems it might have been possible to generate an equally effective tail with less interference drag by rearranging proportions and positions of the various surfaces to eliminate the little "stub" ends of the horizontal tail that projected outboard of the vertical fins, for a tail design more like that of the P-61 Black Widow. With the four-motored Constellation, it seems that it would have been an even simpler matter to select proportions of the tail surfaces such that the vertical fins could have served as "end plates" for the horizontal tail, with no projecting "stub ends" outboard of the vertical fins, thus reducing interference drag. It would also seem that interference drag might have been further reduced, while still meeting other design goals, by selecting a tail design with two vertical fins rather than three.

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    $\begingroup$ No it was just have hangar door clearance with the necessary surface area because the airplane was being designed with private airline hangars of the day in mind. Otherwise a single tail would have been a no-brainer, as it is on 99% of other designs. $\endgroup$
    – John K
    Oct 7, 2019 at 19:56
  • $\begingroup$ The intent of my answer was not to addess why a multi- fin design was chosen, but rather why that particular multi-fin design was chosen. $\endgroup$
    – quiet flyer
    Oct 7, 2019 at 19:59
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    $\begingroup$ Roger.. Don't exclude a little bit of "styling" in the mix. Designers have few areas where artistic expression can trump aerodynamic necessity (although one of the beautiful things about aviation is the happy coincidence that aerodynamic necessity and artistic beauty are in harmony more often than not). Vertical fin shapes and related factors are one of the few places that a designer can make an airplane distinctive from a purely styling perspective. $\endgroup$
    – John K
    Oct 7, 2019 at 22:12

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