Ailerons have definitely arrived in France.
Their working is now understood.
Musée de l’Air et de
l’Espace. L’Aérophile 15 February 1909.
p. 51 [from H. Lefort, ‘L’Aéroplane Wright
et les aéroplanes français’]
Wright ensures lateral stability by wing warping
[‘gauchissement’]. He increases the ‘angle d’attaque’ of one wing while
reducing it on the other. This makes the ‘réactions’ that the wing receives
vary inversely [to the twisting]. So an inclination takes place, and a change
in the horizontal direction of the aircraft. In this way, wings may be
levelled, if required. ‘To combat the damaging turning movement, Wright
combines the action of twisting [the wing] with the action of a vertical
rudder’ [thus achieving a coordinated turn].
p. 52
‘It is moreover useful to notice that the
twisting of the wings is a means of achieving horizontal direction rather than
being a means of [maintaining] stability.’ [A sentence that sums up the change
in French aircraft from late 1908 to early 1909 that made them the best
aircraft in the world.]
The effect of twisting the wing is the
formation of a maximum coupling of a lever arm, producing a force of great
intensity – a greater force than that produced by the rudder in the tail.
[Light has finally fallen on French aviation thinking. It is the banked wing
that produces the turn, not the rudder.]
’Besides that, the [lateral] inclination of
the aircraft produces a considerable horizontal component, annulling the action
of centrifugal force, and favouring the turn.’
Thus a rudder in the tail seems no more than a corrector of the effects
of wing twisting, assuring lateral stability. The Wrights’s rudder can be
combined with the deformation of the wing to facilitate a turn; or it can be
used alone to produce curves of large radius.
p. 53
The Wrights’ aircraft is now indisputably
superior to French aircraft. But French aviators have earned great merit, and
the order of achievement could change.
[It did. Finally the French have understood
how to turn an airplane. The banked wing does the work, not the rudder. An
airplane is not a boat. The realization that the rudder can be applied in
coordination with banking to produce a clean turn – one in which the airplane
is not moving sideways through the air -- is impressive.
By the time this article appeared, many French
flyers had come to the conclusions given here. Following the example of Wilbur
Wright in the late summer and fall of 1908, they had equipped their aircraft
with either wing warping or ailerons. These, they increasingly came to realize,
were not primarily a means of keeping wings level, but a means of intentionally
producing bank – and turns. They now had aircraft that were potentially better
than the Wrights’.]
[They had long been moving towards this
realization. The addition of ailerons to an aircraft goes back several years in
France – but always with the primary intention of keeping the wings level,
rather than of tilting the wing to one side or the other. At least, so it
seems. But in the summer of 1908, before Wilbur Wright flew in France, Blériot
had fitted ailerons to his aircraft that were somehow involved in turning –
either producing the bank that made the wing give some horizontal force for a
turn, or levelling the wings after a turn produced by the rudder. And Ferber
may have been using ailerons to produce turn in summer 1908 also.
In Le
Matin, 26 July 1908, p. 6, is a report on Ferber’s current machine.
Ferber, who, in the newspaper’s view,
‘astonishes by his deep knowledge of piloting planes’, yesterday made several
flights at Issy. His aircraft [he says] is a simple ‘cellule’ whose tips can be
twisted [‘gauchés’] by a lever – i.e. they can take up a more or less
accentuated angle of incidence. There is an elevator in the nose and a fixed
empennage in the tail. ‘Steering is operated by means of the ailerons fitted on
the right and left of the wing {‘cellule’}, but I think I am going to go back
to the rudder’ (for steering, presumably). So ailerons have here been fitted
and are used for steering; but Ferber may prefer a rudder for that purpose.]
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