T-Tail Icing
T-Tail Icing
Joined: Jun 2004
Posts: 1,843
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From: Australia
Until someone comes up with a well informed answer (which this is not), my own personal statistics, having spent about equal time on T-Tail and 'conventional' tail aircraft, is that I've had worse tail iceing encounters with conventional tail aircraft than T-tail. In fact, I can't recall any significant tail iceing encounters at all on T-tail aircraft, but had a few wide eyed moments with conventional tail, particularly in your part of the world!
Regards,
Old Smokey
Regards,
Old Smokey
Joined: Sep 2002
Posts: 2,188
Likes: 6
From: La Belle Province
There's really two parts to the question: are T-tails more susceptible to ice accretion; and are T-tails more sensitive to ice accretion.
For the first question, a T-tail would appear to be completely 'unshadowed' while there is a small amount of geometrical shadowing possible for a low-mounted tail, due to it being behind the wing. This effect is probably relatively minor, though.
Also, one might expect, all other things being equal, that a T-tail may be slightly smaller than a low-tail, which would tend to make it a better ice catcher. (On a swept fin, a T-tail may be slightly further aft, allowing a smaller area for the same tail volume, plus the fflow field at the top of the fin may allow a smaller tail for the same effect; countering these somewhat, a T-tail aircraft often has a shorter fuselage aft of the wing - due to the engine effect on cg - than a low tail aircraft, which would cause the T-tail to be larger in that case.) My own guess is that the T-tail ends up being slightly smaller overall from these effects, but I doubt it is a big factor.
In terms of sensitivity, again the size of the tail will have an effect (smaller surfaces being more impacted by a given ice catch) so any tendency for a smaller size will have an effect here also. I doubt if there's any other systematic design effect that would heighten sensitivity of either design.
For the first question, a T-tail would appear to be completely 'unshadowed' while there is a small amount of geometrical shadowing possible for a low-mounted tail, due to it being behind the wing. This effect is probably relatively minor, though.
Also, one might expect, all other things being equal, that a T-tail may be slightly smaller than a low-tail, which would tend to make it a better ice catcher. (On a swept fin, a T-tail may be slightly further aft, allowing a smaller area for the same tail volume, plus the fflow field at the top of the fin may allow a smaller tail for the same effect; countering these somewhat, a T-tail aircraft often has a shorter fuselage aft of the wing - due to the engine effect on cg - than a low tail aircraft, which would cause the T-tail to be larger in that case.) My own guess is that the T-tail ends up being slightly smaller overall from these effects, but I doubt it is a big factor.
In terms of sensitivity, again the size of the tail will have an effect (smaller surfaces being more impacted by a given ice catch) so any tendency for a smaller size will have an effect here also. I doubt if there's any other systematic design effect that would heighten sensitivity of either design.
Joined: Jun 2002
Posts: 160
Likes: 0
From: UK
The increase of ice accretion on a surface that is experiencing the effects of turbulent airflow is (apparently) very significant. I would suspect that the T tail being further from any disturbed airflow from the main wings would be advantageous. Your experience seems to agree.
Joined: Apr 2004
Posts: 258
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From: vancouver oldebloke
As far as I can recall the 727 had no tail deicing(unlike Douglas, Boeing built the larger horizontal stab area to support the weight)..On the DC8 one had to give a 'shot' of tail deice(3 min) prior to shutoff at the Outer marker..
The A320 had no tail deice fitted..
Cheers
The A320 had no tail deice fitted..
Cheers
Joined: Sep 2002
Posts: 2,188
Likes: 6
From: La Belle Province
Originally Posted by XPMorten
Sometimes, having a T-tail also means you have rear mounted engines.
Ice from the main wing can then fall off and get sucked into the engine.
Has happened on a few occations... .
M
Ice from the main wing can then fall off and get sucked into the engine.
Has happened on a few occations... .
M
