Cozy III Roncz Canard

Description

Vance’s Cozy Mk III Roncz Canard Modification*

Vance Atkinson developed a Roncz Canard modification for the Cozy Mk III back in the late
1980s. Foam cores for this modification are available from Eureka CNC. This is not an
“approved” modification but it has been tested and flown on Vance’s airplane since the 1988.
His research aided in the development of the Roncez canard on the Cozy Mk IV.

The leading edges come already separated with the corners already rounded for the shear
web. The dowel holes come pre-drilled to ensure perfect alignment of the leading edges.

Cozy Ill canard cores include the modification described in Cozy newsletter #53, builder’s hint
#7 and newsletter #60, builder’s hint #1. This modification calls for the removal of approx
1/16″ from the trailing edge fishtail area to allow the elevator to attain it’s 15 deg trailing edge
up limit.

I make 2 types of elevator cores for the Cozy Mk III Roncz canard modification: hotwire template elevators and contour template elevators. The hotwire template elevators are cut per the hotwire templates on the plans. The plans tell you to compare them to the elevator contour templates after cutting and then sand them to shape taking into account 0.020″ of skin thickness. I think the hotwire templates are were probably intentionally made oversized because the small, thin elevators are rather difficult to cut by hand. In fact, the plans tell you to cut them in 2
separate pieces and then micro them together. With the templates a bit oversize they are easier to cut by hand and it allows the builder extra material to be able to sand them to match. The contour template elevators I make are simply cut to match the contour templates to begin with. CNC allows me to make much more precise cuts and to cut material much thinner than would be possible otherwise. Some people still prefer elevators cut slightly oversized so I offer both.

Another thing CNC allows me to do is to cut the elevators full length instead of cutting them as 2 parts apiece as it says to do in the plans. This means you don’t have ta micro the 2 halves together to make each elevator When I ship a canard it cames with elevators cut full length actually they are slightly extra long to allow the builder to cut them down to fit exactly. When I sell the elevators apart from the canard, they are too long and skinny to ship full length so I have to cut them in half to make them less likely to be damaged in shipping.