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Lower Triangular Longerons


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I need some advice on this, I have a spruce kit from Wicks ( why I didn't just buy the stock and cut to size myself I don't know:( ) but anyways, today I'm ready to fit and install the lwr. tri. long. and their no where the size they should be, ones .625 (5/8) and the other is .750 (3/4) so what should I do keep going or replace? and if I replace is there something I can use instead of shipping a 1x1 105" piece of spruce UPS?

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I could not justify the shipping cost for these so I made them out of some local Doug Fir with the right ring count. I made them .700 X.700 they worked great. 20% stronger and 20% heavier. The cost justified the trade. It helps to have a planner. build on STeve

Steve Harmon

Lovin Life in Idaho

Cozy IV Plans #1466 N232CZ


Working on Chapter 19,21

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On my plane I used Oregon pine, just because some was locally available.


Like you, I would have been filled with doubt etc, now that I've got the experience ... I'd just used them and get on with it.


Happy building.

I live in my own little world! but its OK, they know me here!

Chris Van Hoof, Johannesburg, South Africa operate from FASY (Baragwanath)

Cozy Mk IV, ZU-CZZ, IO-360 (200hp) 70x80 prop

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Due to a minor "oaf moment" I broke one of my upper longeron doublers, so I was faced with the same dilemma, of expensive shipping for one piece of wood.


I ended up using poplar, which worked very well, and was easy to get in clear straight grained pieces (which is not often true for pine round here). There's little volume in the lower longerons, so as long as strength is similar, a little bit higher density wood makes only a trivial difference to weight - in my case it was about 20 grams (less than half an ounce) for poplar doublers on both sides.


The US forestry services has a good free publication, "Wood Handbook

Wood as an engineering material. General Technical Report 113." online if you want to compare a candidate to Sitka Spruce.

Craig K.

Cozy IV #1457

building chapter seven!


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