The big makers of flying machines all like to develop their own
terminology and countries do too. Sweden had for many years the standing
requirement to make available all aircraft documentation in Swedish.
Words that did not exist were invented, lots of people were employed
doing this but I don't think it did aviation in the country a fat lot of
good....Boeing and Douglas are good examples of this, perhaps
primordial, urge to differentiate yourself from the crowd by claiming to
know the truth the best.
Being of 'mixed heritag'e myself, (Boeing, Douglas, Airbus, Lockheed,
Fokker, various GA ones plus a bit of Goodyear Blimp to top it off) I
try to refer to what I learnt as a mechanic's apprentice:
Speed brakes have long arms and the panel that comes up has space
between it and the wing. This allows some airflow past the panel and
lift is not perturbed too much.
Spoilers have no free space to the wing. They pop up, create drag and
massive turbulence on the aft part of the chord, hence the term 'lift
dumpers'
Roll spoilers then, are same as the above, but actuated one one side
only dumping lift on one side, helping the aileron.
On later Airbus two ailerons are no longer necessary for each wing,
(Termed Hi and Low speed ailerons) as the control of the roll spoilers
have become more effectively used one aileron is deleted!
The number of possible permutations in airframes must be endless......
There is theory and then there is practice and in reality people make a
plane, then put names on the parts and if on part has more than one
function you make up a name, take flaperons and elevons. If a board is
placed on the top of a wing it will do a lot of damage to the
aerodynamics and it is not so easy to say which effect is the most
important....
My two centavos' worth..
Alex, kit 529
Fergus Kyle wrote:
>They very well may brake by lift
>control, but the term does refer to a family of panels which have no effect
>on lift at all. These speed brakes are hinged panels at the wing trailing
>edge which go vertical upon deployment - and thus affect lift not one whit.
>
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