Re: T-Tailed aircraft

From:         Don Stokes <Don.Stokes@vuw.ac.nz>
Organization: Victoria University of Wellington
Date:         13 May 96 02:08:47 
References:   1 2
Next article
View raw article
  or MIME structure

>I think it's a function of aerodynamics and economy.  R/C gliders that
>are built for manuevring performance often have T-tails while those
>built for maximum lift (for scavenging thermals) have a fortizonatl
>stab inline with the wings.  The horizontal stab riding in the main
>wing's shadow creates less drag and thus probably is more fuel
>economical.

My (possibly erroneous) understanding is that aerodynamicists like
T-tails, due to better handling (the tail is further back on the airfram)
and having the surface in clean air vs in the wing's slipstream, whereas
the structures folk hate them -- the vertical tail has to carry not only
its own forces but all the forces inflicted on it by the stab.

I believe the (T-tailed) BAe146 has highly disturbed airflow behind the
wing due to the flaps extending into the exhaust for better low speed
performance.  The 146 is kinda short, so it seems that having the stab
well clear of the flow from the flaps just when you need the maximum
elevator effectiveness is a good idea.

>>economics now but I liked the days when VC10s, Tridents,
>                                                ^^^^^^^^
>could be confused for a B-727 as a BAC 1-11 could be confused for a
>DC-9.

Trident has flattened fottom edge on the No. 2 intake, 727 has round
intake on No. 2.  Trident Three also has a small booster engine mounted
above No. 2 (how do they number that?).  Also the teardrop shaped side
widow on the flightdeck.

BAC 1-11 has round windows, DC-9's are squarish.

>>DC-8s,707s all looked distinctive and had...
> ^^^^^^^^^
>These two and the Convair jets looked the same, except the 707 had
>that probe on top of the tail.

DC8 has "nostrils" (small air intakes just behind the radome), less
wingsweep than the 707 and bigger windows (but less of 'em).  Not all
707s have the VHF antenna probe either -- 720s usually don't.

Convair CV880 & CV990 have a long nose and very raked back cockpit windows.
The CV990 has rather barrellike engine nacelles.

--
Don Stokes, Network Manager, Victoria University of Wellington, New Zealand.
don@vuw.ac.nz(work) don@zl2tnm.gen.nz(home) +64 4 495-5052 Fax+64 4 471-5386