Understanding T-Tails

[Tophe]

One month ago, checking my sew site http://cmeunier.chez.tiscali.fr/asym_dahu_aeroUK.htm , dear Elmayerle told me interesting things about the asymmetric T-tails I had drawn thinking of dear John Howling Mouse putting T-Tails wherever possible (and a little more than "truly-possible", nicely   ) :
« Unless there's a good reason, I generally don't care for T-tails because they can cause handling problems (for example, the F-101, F-104, and Learjet all have potential problems that way; Learjet solved it first with a stick-pusher if the angle of attack got over a specific limit and then with the "delta fins") and have some definite structural difficulties as well. »
I was very happy    to understand that, thanks again Evan   , because I previously thought that T-tails could be chosen at will by the designer (or modeller... ). Then, today, I have seen 2 gliders in the sky (I live at the bottom of a mountain which is appreciated by glider pilots) and both had T-tails – I had forgotten that maybe 60% of the gliders are designed this way... Then I thought : on a fun glider, there is nothing at the rear, no door no jet nothing, though designers choose T-tails, there must be a very good reason, no   ? I understand the tailplanes are more free from the wing vortex but is that the only explanation ? Evan ? For JHM... and for the JMNs that will look at his lovely XF-16T with frowned eyes, saying this is stupid (or criminal...)... If dear JHM is facing a trial for heresy , what Elmayerle advocate will say to save him from the electric chair ?  (joke)

[elmayerle]

I rather suspect gliders can use T-tails a lot more freely than other varieties of aircraft because they don't fly as fast as other aircraft, this reduces the strength of the wing wake and when/if it would blank-out the T-tail.  Now, something like a T-tailed variant of the F-16 would most likely need some adjustments to the flight control software to handle the problems but I don't see it being an insurmountable problem.

T-tails have one set of problems and asymetric designs have another set and I rather suspect that the two features together would generate some interesting cross-couplings of effects - I'd tunnel-test the daylights out of such a design before it ever flew.

[Tophe]

Thanks Evan.
I agree for the wind-tunnel try first, to save test-pilot life... Dreaming is fun, crashing is not...

[John Howling Mouse]

For the love of T-Tails:

- F-104 Starfighter
- Boeing 727
- DHC-5 Buffalo
- Beech King Air 300 Series
- C-17 Globemaster III
- CT-114 Tutor
- Piper T-Tail Lance
- Piper T-Tail Turbo Arrow
- Fokker 100/70
- DC-9...MD-80
- Vickers VC-10
- Beech 1900 Series
- F-101 Voodoo
- BAC One-Eleven
- Embraer EMB-120
- C-5A/B Galaxy
- Antonov AN-74
- L-29 Delphin
- Martin P6M Seamaster
- Ekranoplan
- Model 45 Learjet
- Antonov 225

Some further info re: the pro's and con's of T-Tails (neither of which mention the simple truth of the matter: a T-Tail looks cool and can update/modernize almost any aircraft, especially for what-if purposes):

http://dutlsisa.lr.tudelft.nl/oso/projects.../new/Ttail.html
http://www.ezresult.com/article/T-tail
http://www.encyclopedia4u.com/t/t-tail.html

[Shasper]

You forgot the BE-200's, and some of the 90 series has the T's as well.


Ves B)  

[Ollie]

And the Challenger, Global Express, etc...

One reason gliders have T-tails is ease of maintenance.  It takes 10 seconds to remove the stab from a t-tail glider.  Just pull a pin and it comes off!

B)  

[Tophe]

One reason gliders have T-tails is ease of maintenance.  It takes 10 seconds to remove the stab from a t-tail glider.  Just pull a pin and it comes off!

I don't understand, Ollie...
T-tails may have separate tail-planes, and low tailplanes can have a common stab, so... The puzzle remains, somehow.

[Ollie]

Gliders have one piece stabs when they are T-Tailed so they can be disassembled more quickly to carry in a trailer.

Look at this picture, it's Thierry helping his father pulling their glider out of the trailer.

You can see where the stab comes in and you can barely make it in the trailer.  You can see, however, that it's a single piece.

This glider can be made ready for flight in about ten minutes, from arrival at the aiport to hooked on the tow plane!

[Tophe]

All right, thanks...  

[F-32]

Don't forget this beautiful big beasty

[Scooterman]

Let us not forget the mighty C-141!  

All hail the T-Tailed Mountain Magnet!


Brad

[F-32]

The most beautiful of them all?

[Tophe]

Let us not forget the mighty C-141!  

I have found on the web better than the C-141 : let us call it CC-14141 or 1441...  

[John Howling Mouse]

Let us not forget the mighty C-141!  

I have found on the web better than the C-141 : let us call it CC-14141 or 1441...

I can just picture the pilots making faces at each other the whole flight!  

This T-Tail thread is like porn-candy to me.  You guys have got ... to... stop...

My heart, my hear---t!!!