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Benefits Of The T-tail  
User currently offlineBrenintw From Taiwan, joined Jul 2006, 1723 posts, RR: 1
Posted (6 years 10 months 1 week 2 days 3 hours ago) and read 10671 times:

I was wondering about this last night. What are the benefits of a T-tail, especially with wing-mounted engines. The only two more-or-less equivalent aircraft I can think of would be the AN-124 and IL-76. They have a similar design, although they do have different roles to play.

Anyway, they both have high-mounted wings with wing-mounted engines. The AN-124 has a standard +-tail, the IL-76 has a T-tail.

From what I understand, the cons of the T-tail are:

Prone to deep stalling
More complex to manufacture and maintain
Empanage may require additional strengthening

Given the cons I've listed above, what are the pros that (in the case of the IL-76) make a T-tail preferable to the +-tail?


I'm tired of the A vs. B sniping. Neither make planes that shed wings randomly!
14 replies: All unread, jump to last
 
User currently offlineKELPkid From United States of America, joined Nov 2005, 6428 posts, RR: 3
Reply 1, posted (6 years 10 months 1 week 2 days 3 hours ago) and read 10666 times:

One of the biggest advantage of T-tails, from an airline's perspective, is that the tail plane is now up and out of harm's way (well, mostly, anways-I'm sure someone has figured out how to damage a horizontal stab or elevator on a T-tail in a ramp rash incident  Wink ) and not interfering with the movement of equipment on the ramp.

Another disadvantage: the flight crew cannot do any pre-flight checks involving the elevator or horizontal stabilizer on a T-tailed bird...including snow and ice accumulation.



Celebrating the birth of KELPkidJR on August 5, 2009 :-)
User currently offlineBond007 From United States of America, joined Mar 2005, 5455 posts, RR: 8
Reply 2, posted (6 years 10 months 1 week 2 days 2 hours ago) and read 10642 times:

Also, of course there is a reason why most high-wing aircraft have a T-tail, right?

AFAIK it's so that the tail and wings are not at the same level, therefore the wing doesn't 'mask' the airflow to the tail.


Jimbo



I'd rather be on the ground wishing I was in the air, than in the air wishing I was on the ground!
User currently offlineTF39 From United States of America, joined Jul 2006, 110 posts, RR: 0
Reply 3, posted (6 years 10 months 1 week 2 days 2 hours ago) and read 10641 times:

Also a nice place to have lunch  Wink

Big version: Width: 970 Height: 672 File size: 465kb


Quoting KELPkid (Reply 1):
I'm sure someone has figured out how to damage a horizontal stab or elevator on a T-tail

Once in while you'd see damage where someone with jittery fingers slammed a cherry picker bucket into it. Usually pretty minor though. Nice thing about a C-5 is you could climb up the ladder inside the tail and open the hatch to do an inspection on top.


User currently offlineBrenintw From Taiwan, joined Jul 2006, 1723 posts, RR: 1
Reply 4, posted (6 years 10 months 1 week 2 days 2 hours ago) and read 10638 times:



Quoting Bond007 (Reply 2):
Also, of course there is a reason why most high-wing aircraft have a T-tail, right?

Well, the two examples I chose both have high wings ... is the AN-124 prone to deep stalling because the wings distort the airflow over the horizontal stabs?

The Fokker-50 has the +-tail and high wings as well, but the Dash-8 has a T-tail, so it seems to me that it's likely to be fairly evenly split.

(I'm not disagreeing with you ... just asking.)

Are there any commercial (jet) aircraft that have wing-mounted engines and T-tails? Most of the jet examples I've found have been military or had military roots.



I'm tired of the A vs. B sniping. Neither make planes that shed wings randomly!
User currently offlineBond007 From United States of America, joined Mar 2005, 5455 posts, RR: 8
Reply 5, posted (6 years 10 months 1 week 2 days 2 hours ago) and read 10629 times:

This thread may be of interest:

Will We Ever See Winglets On The Stabiliser (by NEMA Feb 10 2008 in Tech Ops)

Jimbo



I'd rather be on the ground wishing I was in the air, than in the air wishing I was on the ground!
User currently offlineN353SK From United States of America, joined Jun 2006, 833 posts, RR: 0
Reply 6, posted (6 years 10 months 1 week 2 days 1 hour ago) and read 10617 times:



Quoting Brenintw (Reply 4):
Are there any commercial (jet) aircraft that have wing-mounted engines and T-tails? Most of the jet examples I've found have been military or had military roots.

The 328JET has a T tail.


User currently offlineT prop From United States of America, joined Apr 2001, 1029 posts, RR: 1
Reply 7, posted (6 years 10 months 1 week 2 days ago) and read 10596 times:



Quoting Brenintw (Reply 4):
Are there any commercial (jet) aircraft that have wing-mounted engines and T-tails? Most of the jet examples I've found have been military or had military roots.


View Large View Medium
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Photo © Andreas Mueller - Spotterteam Graz



User currently offlineCptSpeaking From United States of America, joined Apr 2006, 639 posts, RR: 1
Reply 8, posted (6 years 10 months 1 week 1 day 23 hours ago) and read 10575 times:

Not a jet (well...technically it is, but you know what I mean...), however having flown the type, I had to stick it in  Smile


View Large View Medium
Click here for bigger photo!

Photo © Alexander Holmlund



My experience with t-tails is that especially in props, they are great for airplanes used for cross-country flights, but horrible when doing maneuvers. With the tail up and out of the propwash, the elevator axis is always very stable and easily trimmed, but when you get to slower speeds, the response is decreased drastically with the loss of airflow. With a straight tail, you still have the accelerated slipstream going over the tail at lower airspeeds, so you still have plenty of elevator authority.

My  twocents 

Your CptSpeaking



...and don't call me Shirley!!
User currently offlineKELPkid From United States of America, joined Nov 2005, 6428 posts, RR: 3
Reply 9, posted (6 years 10 months 1 week 1 day 22 hours ago) and read 10547 times:



Quoting Bond007 (Reply 2):
Also, of course there is a reason why most high-wing aircraft have a T-tail, right?

AFAIK it's so that the tail and wings are not at the same level, therefore the wing doesn't 'mask' the airflow to the tail.


Jimbo

Keeping the horizontal stab/elevator out of the stream of the jet engine exhaust is a good idea for more than one reason...



Celebrating the birth of KELPkidJR on August 5, 2009 :-)
User currently offlineSEPilot From United States of America, joined Dec 2006, 7198 posts, RR: 46
Reply 10, posted (6 years 10 months 1 week 1 day 17 hours ago) and read 10497 times:

Piper fell in love with T-tails in the 70's, but quickly fell out of love with them. T-tailed Pipers command lower prices in the used market than the equivalent conventional tailed planes; I have only flown one (a Tomahawk) and didn't fly it enough or do enough maneuvers to really see any difference. But I have yet to meet a pilot who prefers them. Mechanics certainly don't; they are more complex and harder to work on.


The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
User currently offlineVenus6971 From United States of America, joined Dec 2004, 1445 posts, RR: 0
Reply 11, posted (6 years 10 months 1 week 1 day 12 hours ago) and read 10448 times:



Quoting TF39 (Reply 3):
Once in while you'd see damage where someone with jittery fingers slammed a cherry picker bucket into it. Usually pretty minor though. Nice thing about a C-5 is you could climb up the ladder inside the tail and open the hatch to do an inspection on top.

Disadvantage of a C-5 T-tail is that at non C-5 bases it is almost impossible to properly deice since most deicing trucks basket will not go high enough to shoot down on it and keep fluid from running into drybays



I would help you but it is not in the contract
User currently offlineCanadianNorth From Canada, joined Aug 2002, 3395 posts, RR: 9
Reply 12, posted (6 years 10 months 1 week 1 day 10 hours ago) and read 10400 times:

From what we just learned in aircrat mechanics school:

T-tail advantages: Horizonal stabilizer and elevators are harder to hit with stuff and generally operate in smoother air
T-tail disadvantages: Can get stuck in a stall, require stronger (thus heavier) vertical stabilizers, and mechanics don't like them


CanadianNorth



What could possibly go wrong?
User currently offlineKELPkid From United States of America, joined Nov 2005, 6428 posts, RR: 3
Reply 13, posted (6 years 10 months 1 week 1 day 6 hours ago) and read 10352 times:



Quoting SEPilot (Reply 10):
Piper fell in love with T-tails in the 70's, but quickly fell out of love with them. T-tailed Pipers command lower prices in the used market than the equivalent conventional tailed planes; I have only flown one (a Tomahawk) and didn't fly it enough or do enough maneuvers to really see any difference. But I have yet to meet a pilot who prefers them. Mechanics certainly don't; they are more complex and harder to work on.

In a GA plane (twin or single), the biggest difference you're likely to notice between a T-Tail and a conventional tail is the (lack of) induced lift on the horizontal stablilizer/elevator due to prop wash. Adding power at lower airspeeds also increases induced lift from the tail (amost instantaneously), making the nose want to pitch a little higher. I've experienced this in the T-tailed Piper Lancer (from the right seat). Power settings have very little influence over pitch in t-tailed props, since the horizontal portion of the tail is now effectively out of the prop's slipstream...

IIRC, this is one of the (myriad of) look and feel issues that bedeviled early prop pilots making the jump to jets, the fact that in jets the horizontal tail was intentionally placed where the engine outflow would have no effect on the tail, whereas most prop planes placed the horizontal surfaces of the tail right in the propwash.



Celebrating the birth of KELPkidJR on August 5, 2009 :-)
User currently offlineFredT From United Kingdom, joined Feb 2002, 2185 posts, RR: 26
Reply 14, posted (6 years 10 months 6 days 20 hours ago) and read 10173 times:

Check this thread out:

T-Tail Pros And Cons

No shame in not finding it. The search function does not make it all that easy.

Cheers,
/Fred



I thought I was doing good trying to avoid those airport hotels... and look at me now.
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