plywood thickness for legal eagle/minimax wings etc

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FoamandTape

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May 8, 2018
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hi all,

recently bought a set of legal eagle plans and am stumped as what thickness and type of ply to use for the front of the ribs. the legal eagle plans (if the ones I purchased are the full ones) are correct it doesnt do a good job of exactly pointing out the thickness. The bill of materials says 4'x4' .8mm ply but that does not sound right?
 

Vigilant1

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1/32" plywood. At what point do we just start calling it paper?

Wood is amazing stuff. It's just incredible that they can reliably peel off veneers so thin that they can glue several together and the result is a sheet just 1/32" thick.
 

lake_harley

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.8MM is what I recall from seeing the plans for the leading edge on a Legal Eagle. MiniMAX (Legal Eagle virtually copied the wing) calls out 1.5MM ply for the leading edge. After a conversation with a weight conscious builder of several MiniMAXs I followed his lead and used 1.0MM on my MiniMAX.

FWIW, a member of our EAA chapter bought a Legal Eagle. To me the leading edge is very "tender". Just a light touch and it can be flexed. Is it OK at 0.8MM...probably, but even at 1.0MM on my plane I wouldn't want mine any thinner/softer.

Lynn
 

don january

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On my Taylor -mono the Horz stab calls for 1.0 MM ply covering however I will be adding foam between leading edge ribs and one sheet of fiberglass cloth before final covering with ply to add strength from prop blast debris and possible bird strike. Wings are primarily 1.5 mm and forward Fus. area is 2.0 mm. .8 mm seams to me to be to weak IMO unless of course your covering your coffee table.:)
 

Pops

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Used 1.5 mm (1/16" ) on the leading edge of the wing on the SSSC. Fuselage sides are 3mm ( 1/8" ) 5 ply.
 

TFF

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Front of the ribs as in nose of the ribs? I want to say 3/16” maybe 1/4”. Same as the capstrip width. The ply covered stuff is 1/32 I don’t think 1/16. Now that is all from memory.
 

poormansairforce

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I pulled out my Minimax plans copyright 1992 and it calls for 1/8" nose ribs with 1/4" doublers at stations 4 and 7 to carry the leading edge butt joints so 3/8" total at those 2 locations. Also, 1/8" at the ends to double up the end rib ply skins. The leading edge is 1.5mm. I guess the birch and mahogany ply were different thicknesses back in the day. I know some have used .8 and 1mm leading edge as noted to save some weight. Wow, that brought back some great memories!
 
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FoamandTape

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May 8, 2018
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Thanks guys! I thought the .8mm seemed awful thin? Will probably end up using something thicker for the LE skin for what I'm building.
 
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