quiz 2 Flashcards
Several forms of wood are commonly used in aircraft.
Solid wood
Laminated wood
Plywood
High-density material
” refers to a member
consisting of one piece of wood.
Solid wood or the adjective “solid” used with such
nouns as “beam” or “spar
is an assembly of two or more layers
of wood that have been glued together with the grain
of all layers or laminations approximately parallel.
Laminated wood
Laminated wood is an assembly of two or more layers
of wood that have been glued together with the grain
of all layers or____________ approximately parallel.
laminations
is an assembled product of wood and glue
that is usually made of an odd number of thin plies, or
veneers, with the grain of each layer placed 90° with
the adjacent ply or plies
Plywood
Plywood is an assembled product of wood and glue
that is usually made of an odd number of thin plies, or
veneers, with the grain of each layer placed ____ with
the adjacent ply or plies
90°
used as bearing or reinforcement plates.
High-density material
High-density material includes
compreg, impreg, or
similar commercially made products, heat-stabilized
wood, or any of the hardwood plywoods
is the preferred choice and the standard
by which the other wood is measured
Spruce
one item common to all the
species is that the slope of the grain cannot be steeper
than _________.
1:15
All solid wood and plywood used for the construction and
repair of aircraft should be of the ___________-
highest quality and grade
For certificated aircraft, the wood should have traceability to a
source that can provide certification to a___________.
military specification
(MIL-SPEC)
MIL-SPEC meaning
military specification
is referred to and specified in some repair documents, but
that grade wood cannot be purchased from a local lumber
company.
“aircraft quality” or “aircraft grade”
To purchase the material, contact one of the specialty aircraft supply companies and request a _______.
certification
document with the order
The MIL-SPEC for solid spruce is
1.______ and for plywood it is 2.______.
1.MIL-S-6073
2.MIL-P-6070B
When possible, fabricated wood components should be
purchased from the 1._______, or someone
who may have a 2._________ to
produce replacement parts for the aircraft.
1.aircraft manufacturer
2.Parts Manufacturer Approval (PMA)
Excellent for all uses. Considered standard
Spruce (Picea)
Sitka (P. sitchensis)
Red (P. rubra)
White (P. glauca)
there Strength Properties (compared to spruce) is 100%
Spruce (Picea)
Sitka (P. sitchensis)
Red (P. rubra)
White (P. glauca)
Maximum
Permissible
Grain Deviation
(slope of grain)
1.15
strength properties Exceeds spruce
Douglas fir
(Pseudotsuga taxifolia)
Port Orford white cedar
(Chamaecyparis
lawsoniana)
May be used as substitute for spruce in same sizes or in
slightly reduced sizes if reductions are substantiated
Douglas fir
(Pseudotsuga taxifolia)
its strength property Slightly exceeds spruce
except 8% deficient in
shear
Noble fir
(Abies procera, also
known as Abies nobilis)
Satisfactory characteristics of workability, warping,
and splitting. May be used as direct substitute for spruce in
same sizes if shear does not become critical.
Noble fir
(Abies procera, also
known as Abies nobilis)
its strength property Slightly exceeds spruce
Western hemlock
(Tsuga heterophylla)
Less uniform in texture than spruce. May be used as direct
substitute for spruce. Upland growth superior to lowland
growth. Satisfactory for gluing.
Western hemlock
(Tsuga heterophylla)
its strength property Properties between
85% and 96% those
of spruce
Northern white pine, also
known as Eastern white
pine (Pinus strobus)
Excellent working qualities and uniform in properties, but
somewhat low in hardness and shock-resistance.
Cannot be used as substitute for spruce without increase in
sizes to compensate for lesser strength.
Northern white pine, also
known as Eastern white
pine (Pinus strobus)
May be used as substitute for spruce in same sizes or in
slightly reduced sizes if reductions are substantiated.
Easy to work with hand tools.
Port Orford white cedar
(Chamaecyparis
lawsoniana)
its strength property is Slightly less than spruce
except in compression
(crushing) and shear
Yellow poplar
(Liriodendron
tulipifera)
Excellent working qualities. Should not be used as a direct
substitute for spruce without carefully accounting for slightly
reduced strength properties. Somewhat low in shock-resistance.
Satisfactory for gluing.
Yellow poplar
(Liriodendron
tulipifera)
To help determine the suitability of the wood, _________ that would make it unsuitable material to repair
or construct an aircraft.
inspect it
for defects
The ____________ grade the wood for possible use.
type, location, and amount
or size of the defects
All
woods used for structural repair of aircraft are classified as
softwood
is typically used for construction and is
graded based on strength, load carrying ability, and safety.
Softwood
on the other hand, are typically appearance
woods and are graded based on the number and size of clear
cuttings from the tree.
Hardwoods,
defects are permitted in the wood species used
for aircraft repair
1.Cross grain
2.Wavy, curly, and interlocked grain
3. Hard knots
4. Pin knot clusters
5. Pitch pocket
6. Mineral streaks
— is acceptable if the grain
does not diverge from the longitudinal axis of the
material more than specified in Figure 6-10 column
Spiral grain, diagonal grain, or a
combination of the two
A check of all four faces of the board is necessary
to determine the1._______. The direction
of ____________ frequently assists in determining
grain direction.
- amount of divergence
2.free-flowing ink
Acceptable, if
local irregularities do not exceed limitations specified
for spiral and diagonal grain.
Wavy, curly, and interlocked grain
Sound, hard knots up to______ in
diameter are acceptable
3/8 inch
Sound, hard knots up to 3
⁄8-inch in
diameter are acceptable if: (1) they are not projecting
portions of 1._______, along the edges of rectangular or
beveled unrouted beams, or along the edges of flanges
of box beams (except in portions of low stress); (2)
they do not cause 2._______ at the edges of the
board or in the flanges of a beam more than specified
in Figure 6-10 column 3; and (3) they are in the 3.______of the beam and not closer than 4._________ to
another knot or other defect (pertains to 3
⁄8-inch knots;
smaller knots may be proportionately closer). Knots
greater than 5.___________ must be used with caution.
1.I-beams
2. grain divergence
3. center, third
4.20-inches
5. ¼-inch
—small clusters are acceptable if they
produce only a small effect on grain direction.
Pin knot clusters