T Tails

[Hman]

Ok - anyone able to advise me of the advantages of an aircraft having a T Tail - I am after a quick lesson in aerodynamics.  I  know it may be  dumb question...

[Doc Yo]

 I don't think its a dumb question. I've seen enough reference to T-tails having severe disadvantages in
some areas, so finding out what they are good for should make interesting reading.


They sure do look cool, though...

[kitnut617]

I'm not an aerodynamics expert but from what I've read it was to get the tail clear of turbulance from powerful flaps.  The downside is that at high angles of attack (as in fighters) the tail gets completely hidden by the wing and causes major handling problems.  In the books I have on the HP Victor the prototypes are described as being 'self-landing' because the tail was right out of the influence of turbulance and when it was tested by the A&AEE it was criticized by the testing pilots as making it to easy for regular pilots and would make them complacent, so when the Mk.1 went into production the tail height was lowered so it couldn't be 'self-landing'

[sotoolslinger]

Well the obvious answer is that  it makes the plane 1000% cooler

[Hman]

Thanks for the info.

I am thinking of making a COIN aircraft using a Mustang as the base, but giving it a new engine and T tail.  Just wanted to know if was a realistic idea.

[sotoolslinger]

Cool idea Darren . One practical aspect of a t- tail on a coin aircraft would be ground/ fod clearance. Assuming a coin aircraft would be utilizing un prepped forward airfields

[Hman]

Very true, my idea is for a simple aircarft, rough field operations thingy! 

[Shasper]

Evan could explain it better than me, and I took a course in elementary Aerodynamics!

Shas

[Hman]

One more thought, T Tails, are never tail-sitters I assume, this because of the lack of airflow over the tail during take off. Or have I got that wrong?

[kitnut617]

Generally the tailplanes on prop powered planes are situated in the prop-wash, so a T-Tail wouldn't work.  I remember reading about the prototype Me.262's after they had removed the piston engine used to test the airframe before the jets were installed.  The test pilot found he couldn't raise the tail (it was a tail sitter before it was a trike) when trying to take off with just the jets and he had to stab the brakes to make it nose over to get the tailplane into the airflow.  I would imagine the same in reverse for a prop plane

[jcf]

One more thought, T Tails, are never tail-sitters I assume, this because of the lack of airflow over the tail during take off. Or have I got that wrong?

[Hman]

Generally the tailplanes on prop powered planes are situated in the prop-wash, so a T-Tail wouldn't work.  I remember reading about the prototype Me.262's after they had removed the piston engine used to test the airframe before the jets were installed.  The test pilot found he couldn't raise the tail (it was a tail sitter before it was a trike) when trying to take off with just the jets and he had to stab the brakes to make it nose over to get the tailplane into the airflow.  I would imagine the same in reverse for a prop plane

Yes I have seen film showing the 262 prototype doing just that - which was why I asked the question!  But now there is a picture to prove 'us' wrong!

[kitnut617]

But now there is a picture to prove 'us' wrong!

Yup! Jon will do that to you every time 

[Shasper]

Ok after juggling my memory a bit . . . a T-Tail's main advantage also doubles as it's downfall: the elevator is located outside the prop/jetwash. A normal tail layout has the elevator flying thru the propwash, thus its subject to the force exerted by the engine(s), so when the power settings are changed the pilot will have to re-trim the elevator to compensate in order to maintain level flight. The elevator on the T-tail is positioned outside of the jet/propwash, thus is not affected by changes in power setting, plus (if I'm thinkin right) it will provide better control response in the pitch regime . . . This is where it gets dangerous, if the position of the aircraft becomes such that the airflow to the tail is blocked (like in a stall), the elevator has NO control effectiveness whatsoever.

Ok I think I got most of that right but feel free to correct me if I'm off. . .

Shas

[jcf]

Generally the tailplanes on prop powered planes are situated in the prop-wash, so a T-Tail wouldn't work.  I remember reading about the prototype Me.262's after they had removed the piston engine used to test the airframe before the jets were installed.  The test pilot found he couldn't raise the tail (it was a tail sitter before it was a trike) when trying to take off with just the jets and he had to stab the brakes to make it nose over to get the tailplane into the airflow.  I would imagine the same in reverse for a prop plane

I have to wonder if the problem was more to do with the relatively low power and slow acceleration of the early jet engines rather than just horizontal stabilizer positioning.
That early 262 would most likely eventually generate enough forward momentum to lift the tail, but you'd probably be out of runway by that time. 

The Yak 15 was a tail-dragger jet and evidently took off with relative ease.

As to tail-draggers and T-tails, both the Westland Whirlwind and Fairey Barracuda, while not T-tails per se, had highset horizontal tails coupled with
a tail-dragger layout.

Jon