Technical data

7 - 4 Page Date: 6. April 2010
Section 7
Description and Operation of Aircraft and Systems
Pilot´s Operating Handbook
EXTRA 300LT
7.3 WINGS
The wing is of CRP construction. The dual chamber main spar - fullfilling the requirement for
fail safe design - consists of carbon roving caps combined with CRP webs. Core foam is a
PVC foam (Divinycell HT 50). The wing shell is built by a Honeycomb sandwich with CRP
Laminates. On the surface there is a protective layer of GRP. To prevent buckling of the shell
plywood ribs are used. In the area of the wingtanks is a layer of CRP laminate with an
incorporated aluminium thread bonded to the metal fuselage structure as means of lightning
protection.
The connection to the fuselage is arranged by two bolts piercing through the spar parallel to
the centerline of the fuselage and two brackets at the rear spars. Integral fuel cells are
provided behind the main spar of the wing extending from the root ribs to half the span of each
R/L and L/H wing. The ailerons are supported at three points in spherical bearings pressed
into aluminium brackets. To reduce pilot's hand forces the ailerons are equipped with
"spades" to decrease pilot forces. Ailerons are controlled via the center bracket. To prevent
flutter the ailerons are weight balanced in the overhanging leading edge.
7.4 EMPENNAGE
The EXTRA 300LT possesses a cruziform empennage with stabilizers and moveable control
surfaces. The rudder is balanced aerodynamically at the tip. Spars consist of PVC foam
cores, CRP caps and GRP laminates. The shell is built using honeycomb sandwich with
GRP laminates.
Deviating from the other control surfaces the spar webs of the surfaces of the elevator is built
by CRP. On the R/H elevator half a trim tab is fitted with two hinges. The control surfaces are
mounted in spherical bearings (exception: Trim tab). To prevent flutter rudder and elevator are
mass balanced. The balance weight for the rudder is installed in the rudder tip while the
balance weights for the elevator are mounted on the outside elevator tips.