T-tail aircraft

[Rainboe]

Re: T-tail aircraft

You lot have got to be stopped before you do any more damage!
<Advantages for engines at the rear:

1. Less worrying about CG issues, since the heavy stuff is already at the rear
Nonsense- heavy weight at the back makes load and balance more critical
2. Less wires, control runs etc
Nonsense

3. Engines are easier to replace (everything is grouped together)?
No. Watching an engine change on VC10/707- I think easier on a 707. The VC10 engine is higher and harder to get at.

Disadvatages:

1. Compressor blade loss could take out both engines and damage the tail if severe enough

2. Thrust changes on approach work the wrong way, i.e, more thrust = pitch down, less thrust = pitch up
Nonsense. The VC10 had no thrust/pitch change, the 737 has plenty

3. More dangers for overrotation? (Just a thought)
Why?

4. Needs a T-tail design to avoid melting bits off the aircraft
What?

Advantages of a T-tail:

1. Tail is in clean air

2. Can be a single unit, therefore can be stronger
There isn't much difference from a 707/737 tail which has a carry through structure.

3. Can be set further back from the CG, improving pitch authority
Engines at the back puts the CG further aft, so you need all the aft positioning you can design in
Disadvantages:

1. Possible pitchup following a stall, could be unrecoverable
That's why they have 'anti-pitch-up protectors' (stick push)

2. Previous trait requires more effort designing the flight control system, wing mods etc
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Confab has covered most things but I'd also add:-

Advantages:-
Completely clean wingsBut to pay for that, you have lost all this weight from the wings and put it on the fuselage, so lose all that wing bending relief. You need structurally stronger and heavier wings.
Cabin noise is lessened- happy SLF!
Also...very minor but greater margin of error for crosswind landings as no low slung pods. So the DC9 without those engines under the wings has a nice cheaper shorter undercarriage making the wings closer oto the ground so you are just as likely to scrape a tip or flap track! No better than a 737!