Plywood choices

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amv8vol

Active Member
Joined
May 18, 2012
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35
Location
Long Island, NY
I am about to start building a Jodel Dr250. THis aircraft was originally specified with Okoume plywood , mostly 1.6 & 3.2mm thickness and birch plywood in some stressed areas. Aircraft Spruce has a domestic Mahogany Plywood the right sizes in mil-p-6070 specs. I found a supplier for 1.5 & 3.2 Okoume from a marine supplier in BS 6566 spec's. There is a higher specification BS1088 but I was told the thinner plywoods cannot meet that specification. So I am looking for a recommendation .. Is ACS's Mahogany a good substitute for Okoume (or even better) and or is a BS 6566 Okoume adequate for aircraft use?
Thanks
 

fly2kads

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Jan 2, 2010
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1,843
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Justin, TX
I haven't seen the thinner sizes of okoume in anything but the BS 6566 specification, which is actually similar to the BS 1088 spec. For an application that is continuously immersed in or exposed to water, it might matter, but for an aircraft it probably won't. I think there are a number of European aircraft that have been built with BS 6566 okoume that are doing just fine. I have heard some boat builders complain that some cheap Chinese imports have not performed as well as products from the more established boat industry suppliers, but I don't have any first hand knowledge. It might be worth paying attention to who made the panels, as it may be a case of getting what you paid for.

I would defer to others with more knowledge of the Jodel design, but in general mahogany should be an acceptable substitution. Mahogany is denser than okoume, and is therefore heavier in a given plywood thickness. For as little wood volume as the skins represent, it will only amount to a few pounds at most. It is also proportionally stronger. Mahogany won't dull your saw blades as fast as okoume, due to the latter's silica content. I think mahogany has a nicer texture, but that's personal preference and is probably not as important in an airplane. In contrast to the okoume, I have never heard any complaints about the quality of the MIL spec plywood.

I think you could do fine with either. If the availability and price were okay, it might come down to your personal preference.
 
Joined
Apr 30, 2012
Messages
7
Location
salvatierra miño
Hello amv8vol My name is Enrique, I am a pilot from Spain. In this moment I also building my own airplane, also France Design, "Gazaile". I can manufacturate okume plywood, 1,5mm 2mm 2,5mm. No problem. for our aircraft, no matter certified bs1088 (test in boiling water over 72 hours) This is important in wooden ships, engine room, kitchens, etc. .. heat, humidity, sea water .... 2 important things type of glue and okume 100% quality, outside + INSIDE + outside Most important is the insideof the plywood. Type of glue: hydrophobic Plywood cheap, (for building houses... or Chinese ) ... have poor interior quality, or bad glue.

Contrachapado-plywood - Construcción del avión Gazaile 2 | Construcción del avión Gazaile 2

pw1 (Small).jpg
 

amv8vol

Active Member
Joined
May 18, 2012
Messages
35
Location
Long Island, NY
I found another supplier in the US World Panel Products Inc They claim that their 1.5mm and 2.0mm are also BS1088. At $60-$70 a sheet it is significantly less expensive than Aircraft Spruce's Mahogany, and of course the plans specify Okoume. I suspect much of the plywood today is Chinese origin.
I received thier Okoume plywood and it looks good, I haven't started cutting yet, waiting for my Spruce from AS.
Thanks
David

 
Last edited:
Joined
Apr 30, 2012
Messages
7
Location
salvatierra miño
Hello David

I just saw the page the World Panel Products....

You must be careful with plywood of 1.5 mm, it only takes 2 ply (must be 3). Missing inside?

Do not use in structural zone.

Have you bought a whole sheet? 2440x1220 x 1,5mm

What weight do you have?


Saludos.
 

amv8vol

Active Member
Joined
May 18, 2012
Messages
35
Location
Long Island, NY
the 1.6 is 3 ply , i bought 3 sheets of 1.5l, I will be following the plans re plywood sizes and locations. I have not weighed the plywood, I'm not sure how I could do that easily
 
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