On the Antonov-225's split vertical stabilizers, there is a 'spiked' structure pointing directly rearwards (as you can see below). What is the purpose of these two structures?
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2$\begingroup$ Possible duplicate of What is the purpose of the sharp pods under airliner wings? $\endgroup$– Greg HewgillMar 17, 2016 at 2:28
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4$\begingroup$ @GregHewgill, I don't think the purpose is the same. It clearly has aerodynamic reason, but at that point there are only the stabilizers and they are ending rather smoothly due to the sweep, so they shouldn't need shock body. I'd rather guess it has something to do with interference between the horizontal and vertical stabilizers. $\endgroup$– Jan HudecMar 17, 2016 at 7:03
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12$\begingroup$ In either case, this is definitely not a duplicate, because even if the purpose was the same, it is absolutely not obvious and therefore needs a separate answer. $\endgroup$– Jan HudecMar 17, 2016 at 7:11
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1$\begingroup$ @mins Thank you! Yes, I will amend the post with the link. $\endgroup$– TombombadillyMar 17, 2016 at 12:34
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$\begingroup$ @JanHudec: Thanks, I've retracted my duplicate close vote. $\endgroup$– Greg HewgillMar 17, 2016 at 19:26
1 Answer
It appears to be the extension of the aerodynamic fairing between the vertical and horizontal tails (note that the horizontal tail extends outside the vertical one). It can be seen more clearly in the following image.
Image from diecastaircraftforum.com. Original image appears to be from airliners.net
This type of fairings (usually called bullet fairings) are found in 'T' tails and other types of tails (like cruciform tail) where two surface intersect each other at right angles and are used to reduce interference drag (and flow seperation). For example, the following image shows the fairing in C-141 Starlifter, an aircraft with 'T' tail.
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$\begingroup$ I thought about this as well, but I wonder why they extend so far backwards past the intersection? $\endgroup$ Mar 18, 2016 at 13:12