Cumic Build – – Jan 2019

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The 100 inch Cumic V-Tail was one of Lee Renauds prototypes that was never kitted, apparently there were some Prototype Kits handed out back in the day.

The Plans show  full flying articulating V-Tail surfaces

 

The wing is two panel, plug in style like the Aquila’s and Sagitta, the pod form, more reminisant of the Aquila’s though

The inner panel is  constant chord and the outer is swept the complete wing has a straight trailing edge

The fuse is a  thinner Aquila style wood and ply pod and boom style.

 

Cumic designed in 1972 and updated in 1973.

From the Plans

Airtronics Design, July 20, 1972

Revised Mar 12, 1973

100 Inch Wing Span Standard Class

620 Sq In

16:1 Aspect Ratio

@#$%

Well onward and upward

There will be some changes.

  • the stab set will be fixed
  • the trailing edges will be done with some 3/16 wide spruce
  • the wing rods, I believe they are shown as .187 dia, will be changed to a single 1/4 inch rod
  • the poly hedral, and dihedral angles will be increased
  • the canopy will be a little shorter, Aquila canopy, as near as I can tell the design shows a Canopy app. 3/4 inch longer more like what was used on the Grand Esprit, though perhaps the Cumic fuselage is narrower
  • spoilers will be added, dial cord actuated
  • I never had any good luck printing a PDF file for a plane build and being happy with the results, so I have made some assumptions, gathered some dimensions, and recreated the Cumic in Auto Cad. As I go along I can pick up size info from the plans and Build this Beauty

Some more rib detail as well as Trailing edge notches

the ribs get cut one at a time with a single edge razor blade, and later get cleaned up with sandpaper, and have the notches cleared correctly

the inner panel ribs are in the forward stack

I had previously marked the trailing edges for the rib notches and use a stop and eyes, to control the width. The original plans did not have these notches

checking for fit, the outline of the wing panels are on a piece of Kraft paper, I do that work with some dimensions and a Mechanical Drafting arm, the good ole days

the tip panel ribs two of each, and the notches are cleaned at a bit of an angle to suite the spar

Jan 27 2017

leading edge, trailing edge, trailing edge caps, spars

Just like building a kit, getting all the long lumber together and cut to dimension

More lumber , the spars are 3/32 x 1/4 Inch

Trailing edge notches were previously added to suit the rib tails

tip panel, lower spar trailing edge and 7 ribs. Want both panels the same, measure and precut spars and mark the rib location, never fails

Feb 01

cut outs for the spoilers, the original Cumic did not have any spoilers

looks like the inboard end of an inner Panel

lower spar ribs and rear trailing edge

set to glue down some more ribs, I have a Mark on the lower spar, and there’s a line going back to the TE to align the ribs

Feb 02

Ribs are  modded from original plans to suite capped trailing edges and notches at ends

tip up, match panels at polyhedral join

gussets at root corners

leading edge top to match rib top for later upper d tube sheet overlap

Panel stack

3/32 square diagonals glued in three places

Feb 11

tip panel build continues, diagonals are proud of the bottom surface over the wing and run over the lower spar

ddd

diagonal lumber ripped to dimension

shear webbing gets diagonal notches added to suit each rib bay

something like this, the height of the shear web still needs some adjustment

I like to thin use thinner material for the shear webs as I proceed out the tip