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flybeech21

Birch Plywood Issue

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I am underway with chapter 4. I have ran into my first snag. The 2' X 4' finished birch plywood is too small for the slightly larger Aerocanard FG firewall. It is the perfect size for the Cozy firewall. The Bill of materials calls for this size sheet but is not big enough. uuurrrggghhhh!

 

Has anyone else had this problem, or am I just doing something wrong?

 

Kevin

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I believe most everyone uses regular plywood for the earlier chapters and then use the real deal once the spar is mounted.

I'm speaking from the Long-EZ perspective here.

 

At least you could continue your build while you sort this out.

 

Wicks has all the materials listed by chapter in PDF format which might help in the future. From what I can see, both kits list the birch as 2' x 4'.

What do your drawings call for?

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Well, that's the problem. My plans call for a 2' X 4' section. But the Aerocanard Drawings have both the Cozy and the larger FG bulkheads. The larger drawings will not fit the 2' X 4' section with out overlapping. The plans do call for a temporary firewall from regular plywood. I am just trying to sort this out to see if it is my mistake or an error in the plans.

 

Kevin

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I'll assume the 48" dimension isn't the problem...

 

Will the parts fit if the top arc of the upper firewall fits into the NACA cutout of the lower firewall? It's real close on the Cozy-IV. How tall is the upper (and lower) on the Aerocanard anyway?

 

I don't think it's specified, but can you rotate each firewall on your plywood... not parallel or perpendicular to the face grain in other words. Didn't hear this from me though.

 

Worst case, order out another sheet. You'll need the lower firewall way before you'll need the upper anyway. And the small scrap pieces make for nice templates, stir sticks, jigs, ... Expensive, but nice.

 

Rick

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your fw is bigger that 4' ? 48" and its ok top to bottom ? (spar to naca)

the cozy has a 4x8" filler on both sides, dose yours? that will add 8 more inches.?

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The 4' dimension is fine. The wood needs to be 26" opposed to 24". If I center up the upper and lower firewall, the corner of the naca scoop cutout is where the two overlap.

 

If I rotate them any, there is even less room. Thanks for the suggestion though.

 

I dread buying a larger peice of plywood. ACS sells only 2' X 4' or 4' X 4'. $45 vs. $90. And, I will have a lot of expensive plywood left over...:confused:

 

Oh well... I am sure this is just the beginning of the hurdles..

 

What is upsetting to me is the fact that the AeroCanard plans list the wrong size of plywood needed for the chapter.:mad:

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This isn't in the plans, what about making a scarf joint at the top of the upper firewall? Bevel the joining edges 10 degrees or so (good and steady with a hand plane should do), lap and glue up the joint w/ epoxy, glass per plan.

 

As I read the plans, the upper portion bonds to the canopy / turtleback, it doesn't appear to be doing a whole lot of structural function. Unlike the lower FW, and lower portion of the upper FW (engine mount locations).

 

YMMV, don't forget to floss, ...

 

Rick

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Well, I threw in the towel on plans building the AeroCanard FG. After contacting other builders and talking with them and experiencing a couple of other plans errors, I have decided to purchase the Kit for the FG instead.

 

Back to the drawing board.... This should result in having an airplane flying sooner anyway....

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The 4' dimension is fine. The wood needs to be 26" opposed to 24". If I center up the upper and lower firewall, the corner of the naca scoop cutout is where the two overlap.

 

If I rotate them any, there is even less room. Thanks for the suggestion though.

 

I dread buying a larger peice of plywood. ACS sells only 2' X 4' or 4' X 4'. $45 vs. $90. And, I will have a lot of expensive plywood left over...:confused:

 

Oh well... I am sure this is just the beginning of the hurdles..

 

What is upsetting to me is the fact that the AeroCanard plans list the wrong size of plywood needed for the chapter.:mad:

i don't here you say center around the main spar ? are you forgetting to mince out the main spar thickness ?

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