The plans specification for the nail seems useless. They're only 1/2" long, and are specified to be every 2" along the spar, and every 1" along the top of the ribs. I bought a bag of the nails, and they're above as strong as a staple. I can't see them going through the aluminum and all the way into the spar. They're too short.I would certainly recommend drilling, unless there is some compelling reason not to drill.
I think those missing nails every 2" is a big defect.There don't seem to be many nails along the spar
Very informative! Thank you.A couple of tricks for bonding or coating composites and woods...
Ensure Your wood is kept dry. Moisture interferes with all bonds/coatings. and wood is subject to expansion and contraction with moisture content. the intent of finishes is to stabilize moisture content and prevent damage due to tramp moisture/fungus/mold intrusion over the expected life time. One handbook stated that wood should have no more than 20% moisture content, ever... about 10-to-15% preferred... depending on species.
MIL-STD-171 indicates that bare wood should be sealed with epoxy primer [after assembly/bonding], non-chromated preferred; and then over-coated with a layer of polyurethane [over epoxy primer ] as a very useful finish stack for enhanced environmental sealing/exclusion. Recommended primers [non-chromated] for are per: MIL-DTL-53022 or MIL-DTL-53030 and polyurethane per MIL-PRF-85285 [specs readily translate to commercial numbers].
Primer/paint that is 1-part [base and thinner as required] has a relatively simple deposition... apply 'as-is' or 'thinned' and allow to dry [evaporate-off thinning solvents]... forming a coating that is resistant to most environmental factors for a short term... but is not resistant to long-term environmental and chemical breakdown in service. Aggressive solvents can usually degrade or remove these finishes... and are used as 'paint strippers'.
On the other-hand, primer/paint that has 2-or-more chemical parts [base + catalyst and thinner as needed], chemically cures over several hours/days to have high physical resistance to moisture absorption/penetration, the environment over-all... and most chemicals/solvents/detergents/abrasion encountered during cleaning. Specially formulated chemicals are used to breakdown coating chemical bonds structure... to degrade/remove these finishes. Generally speaking the harder the chemistry of these type finishes to degrade... the tougher/longer-lasting the paint system.
Thanks! I managed to source the same plans. I then ordered a bag of 1/2" 20 GA nails, which are tiny!For whatever reason I have a copy of the Ace Aircraft drawings wing construction.
Item 23 is a 1/4 x 1/4 inch filler strip on top of the spar and between each rib.
Item 38 is .020" aluminum for the leading edge
Item 57 is 1/2" x 20GA nails.
My thoughts exactly! There only seems to be one nail along the spar, at each rib, unless there are smaller nails under the fabric which I can't see.I think those missing nails every 2" is a big defect.
The few remaining rib nails carry the load and have failed. The entire leading edge could separate in flight.
First thing is to install a standard lower wing inspection hole if needed for inspection.