Fabrics Flashcards
What should be done before applying any fabric to an aircraft?
Inspect the structure and fit any internal parts such as control cables or fuel tanks.
What are the materials used for fabrics on aircraft?
The fabric Tapes- repairs and chafing mainly Thread Stringing Eyeleted fuselage webbing
How should fabrics be stored?
In clean, dry conditions, out of sunlight and kept at 20C
How is the wood protected from the dope adhering to it?
Adhesive cellulose
Aluminium tape
Dope resistant white paint
How are fabrics attached to aircraft with a tubular metal fuselage?
Longitudinal members connected to the wooden formers
What tape is used to protect against chafing and stringing?
Cotton tape over the wood.
What are the two methods of covering fabrics?
Prefabricated envelopes
Blanket
How does the prefabricated envelopes method work?
The fabric is manufactured so the envelope of fabric slips over the area being cover, loosely until the fabric is doped to tightly cover the area.
How does the blanket method work?
Lengths or multiple connected lengthsof fabric are made on site to cover the aircraft.
Either doped or hand sown to complete the covering
What are the hand sown stitches, used and when are they used?
Herringbone (baseball)- repair
Boot- repair
Overhand and lockstitch- trailing edge, wing tips, wing roots.
What are the two seams used on aircraft?
Balloon seam(french fell) Lap seam
What is a balloon seam?
The fabric is folded back on itself and machine sewn.
When should a lap seam be used?
At the manufactures request
When can fabric covering NOT be parallel to the bias or fore and aft line of the aircraft?
Trailing edges
Leading edges
What should be applied to non-waxed needles when hand sewing?
Beeswax
What are the main knots for stringing?
Boom stringing
Splice knot
What is boom stringing?
Cotton tape is used to cover the top bottom and rib booms, then the fabric is stitched to the cotton tape and doped.
What can happen if there is too much tension on the fabric?
The ribs can be distorted
What is the slipstream area for propellers and multiple engines?
Propeller- diameter of prop plus on rib either side
Multi engined- entire gap between slip steams
What are some other methods of attaching fabrics?
Strips Special stringing Adhesive Plywood Metal
Where are drainage holes positioned?
At the bottom
What are drainage eyelets?
Circular shapes doped into the fabric that open up for drainage
What are shielded eyelets?
Drainage eyelets with a shroud to ensure they are positioned right. An be used to stop sea spray and can only be put on certain places
What are the three methods of inspection panels for fabrics?
Wooden frames
Zip panels
Spring panels
How are wooden frames used for inspection?
Patches of fabric on wooden frames are cut off to inspect the inside, however it must be repaired after inspection
How are zip panels used?
Two zip fastener are sewn into the fabric in the shape of a vee. This allows easy access for inspecting often, but be careful not to clog the zips.
How are spring panels used for inspections?
Doped plastic rings are used like springs to release them and open the panel. Suitable for light aircraft only
What should be done before repairing fabric damage?
Find the cause for the damage
What are the main methods for repairing cuts and tears?
Herringbone stitch Wooden frames Darning Insertion Boot stitch Alternative insertion repair
What is darning, and what are the limits of damage it can be used on?
No more than 50mm holes
Serrated fabric patches are put over the damage with the stitching following the warp and weft.
When would insertion fabric repairs be done?
For damage over 100 mm
How is the alternative insertion method different?
The stitching is done along folded edges with the edges doped down.
What are the different tests and testers for fabrics?
Maule tester
Seyboth tester
Bursting strength test
Lab test
What are the 2 main types of man made fabrics?
Glass fibre
Polyester fibre
Why are fabrics doped?
Waterproofing
Air proofing
Tautening of natural fabrics
Lightproofing
What is dope?
A number of resins mixed in a solvent with plasticiser, pigments, and colour
What can happen to dope over time?
It becomes acidic
Why is dope proof paint used?
To resist the solvent nature that softens normal paints
Why is aluminium dope used?
To make the fabric lightproof and to protect it from uv radiation.
What else could be used in conjunction with dopes for fabrics?
Thinners
Fungicides
Cleaning agent
What are the safety precautions for dope?
Low flash point and dense vapour
Ignites easily from static
Fumes from solvent
What sort of conditions are needed when doping?
Maintain a suitable airflow
Maintain a suitable temperature (21C-26C)
Around 45-50% humidity
Everything should be clean.
What should be done before applying dope?
Inspection of the fabric and structure
Mixing of the dope, keeping to the conditions required.
What are the stages of applying dope to natural fabrics?
Apply the primer layer Apply drainage grommets and eyelets after an hour Filling coats Cross coat of aluminium dope Finishing coats
How are dopes applied to man made fibres?
Priming coat
Filling coat
Finishing coat
What should be considered with doped fabric aircraft?
Check the weight of the aircraft and keep it in tolerance
When the aircraft is recovered and re doped, weigh it again
After recovering, check the static balancing.
