Golden Era Model Service
High Quality Plan Sets for Radio Control Aircraft
74 inch San Josè
A 1948 design by Antonio Arria

1/19/2016

Setting up the spar shaping jig.  The iron is 1/4 x 3/4 inch mild steel flat bar, the spar material is clamped between it with the bars
offset according to the dimensions on the plan.  The digital caliper is available from Harbor Freight.  Orchard Supply has the flat bar, or any metal supply store.



A shaped spar end.    I filed until I could feel the iron on both ends.  Be careful to keep the file level so you get an even chamfer.


All of the 1/8 x 3/8 spruce spar components.  One thing to look out for is to make sure you have the spars turned the right way
when you make the second cut, it's possible to have the tapers cut the wrong way.  How do I know that?  Make the lower
main spars first, if there is an error you can convert them to upper spars which are a little shorter.



A closer photo of the spars.  Some years past I bought several different thicknesses of spruce stock from Aircraft Spruce and Specialty, 1/4, 3/8, and 1/2, in
4 foot or a little more foot lengths.  The grain quality is very much better than what is available from hobby suppliers.  I have it resawn it to the proper thicknesses.
 Note I marked the main spars for location.  Before the wing ribs are assembled to the top spar, glue the  upper spar doublers to the upper spars.
 Use one of the 1/8 ply center dihedral braces as a jig to locate how far the doubler should be  from the upper spar end.

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