Why does the Hercules Transport aircraft have such a disproportionately large tail fin?

Question

Why does the Hercules Transport aircraft have such a disproportionately large tail fin?

Answer 1

It really is about the right size for the airplane.  From certain angles it probably looks larger than it really is.  And, as mentioned, the C-130 is a good low-speed performer and needs plenty of control authority.

Answer 2

3 things.  Lift, control, and there is a huge unloading ramp under that tail.  A herc is a short runway , heavy lifter. it needs more tail area to get better lift, and also better control. Also because of a ramp that can dump a jeep out in flight, they had to oversize it and lift it higher on the aircraft.

Answer 3

its for balance , and keeps it stable in the air

Answer 4

There are a number of reasons that the Herc's tail seems disproportionately big.

The first, as the other posters have mentioned is that because of the rear opening doors, the base of the tail is placed a little higher than most aircraft as can be seen in this picture http://www.airliners.net/photo/Chile---A...  that makes the tail look really big.

But, the tail of the Herc doesn't just look big, it is pretty big. Compared to other transport aircraft such as the C5 Galaxy, the Herc itself doesn't seem that big, but the tail does seem pretty large. This is because even though the Herc is a heavy lifter, it's actually a pretty short plane from nose to tail.

In order for an aircraft tail to create the required force to yaw http://en.wikipedia.org/wiki/Flight_dyna... the aircraft, you have to take into account both the force created by the tail, and the distance from the tail to the aircraft's central axis. This distance is multipled by the force exerted on the tail and is called the moment http://www.saburchill.com/physics/chapte...

Therefore, the shorter the distance, the larger the force required to create a certain moment. So, since the Herc is a heavy airplane, you need a pretty strong moment to create the required yaw. But, since the distance from the center of the airplane is relatively short, you need a bigger tail which creates a larger force.

You can see the difference in the size of the vertical tails of the Boeing 747-200 http://www.airliners.net/photo/Pakistan-... and the Boeing 747SP http://www.airliners.net/photo/Yemenia--...  Even though the 747SP is smaller than the 747-200, it has a larger tail because it is shorter.

Hope this helps,

James Ball

Author of "So, You Want to be a Pilot, Eh? - A Guidebook for Canadian Pilot Training"

http://www.piloteh.com

http://www.piloteh.blogspot.com

Answer 5

As a transport plane, it has a back door that can open and discharge cargo in flight. The large tail fin compensates for the plane flying with the rear door open in flight by being larger than normal planes. Incidentally, I have parachuted out of the back door of a hercules a few times on NATO exercises.