Cozy MKIV - Unofficial CAD Files

NOTE: Be sure to "Load to local disc" (or the equivalent for your browser) before clicking on any zip'ed CAD file. The GIF, JPG and PDF files are directly viewable.

ALL downloadable files are "zip'ed" for faster transmission.

INTRODUCTION - Aircraft 3 - View

Michael DeNigris has graciously provided this CAD DXF file which contains the 3 View drawings shown on the back of the owner's manual and the plans. Ian Douglas has provided an alternate version that may work better with some CAD software.

Doug Shepherd created the PDF files from the CAD files.

Full Aircraft Drawings

Paul Gies has created this full set of "M" drawing reproductions from accurate CAD files.

CHAPTER 4 - Fuselage Bulkheads

As of March 25, 1999 Nat Puffer has agreed to allow us to re-post these Bulkhead CAD files. Thanks, NAT!

I'd like to thank Lee Devlin in Greeley, Co. for contributing these CAD files. Here's a README file he's provided, describing the templates.   Once again, Doug Shepherd created the PDF file.

Bil Kleb (or bil kleb) came up with these drawings of the Landing Gear Bulkheads for the COZY MKIV/AeroCanard Rear End. Once again, Doug Shepherd created the PDF file.

Chapter 7 - Fuselage Exterior

Steve Hagan has provided a DWG drawing of the NACA scoop layout.

Chapter 8 - Headrest, Heat Duct, etc.

Jim Springer has provided a drawing of the foam parts.

CHAPTER 10 - Canard

I've had a number of requests recently for canard airfoil data. I've provided a ZIP file of the canard, elevator, combined element, and NON-MODIFIED Eppler 1230 DAT files of these airfoils.  The DAT file includes X,Y coordinate pairs for the upper and lower surfaces of the airfoils.  You can input this data to a CAD system and then join the points with a spline to get the airfoil shape.

CHAPTER 11 - Elevators

Ed Richards has graciously provided his DXF drawings of all the Elevator hardware. Once again, Doug Shepherd created the PDF file.

CHAPTER 13 - Nose

Jim Springer has provided a drawing of the foam and other miscellaneous parts.

Jack Wilhelmson has created an adjuster to change the effective length of the VENGR retract mechanism. We have 3D IGES and DXF files of this part.

Cliff Cady has supplied a picture and DXF file of his adjustable rudder pedals.

Cliff's pedal installation
(picture 1)
Cliff's pedal installation
(picture 2)
Dennis Oelmann's Rudder Pedals
(similar if not identical to AeroCad's)
RudPed.jpg (5376 bytes) RudPed2.jpg (12965 bytes) Dennispedals.jpg (17199 bytes)


Control System

James Russell has created detailed isometric drawings with the whole control system clearly labeled.


Trim System

Keith Spreuer came up with a neat roll trim system which eliminates much of the hysteresis involved with the standard system. Click on each image to see the full size version.

Bob Davenport came up with a cantilever spring pitch trim system.  Ken Miller uses it for his electric system that he sells. The plans for the original Davenport System are here in PDF format.

Throttle Quadrant Levers

Kevin Walsh has provided these drawings for modified throttle quadrant levers for use with Push-Pull Cables.


Wing Tie Down System

Robin Du Bois came up with this very elegant retractable tiedown system for L.E./COZY type aircraft. We have PDF and GIF versions of this idea.

Robin wants me to point out that although the images claim that the tiedown should be attached to the inboard wing bolt, in actuality they should be attached to the OUTBOARD wing attach bolt.

  • GIF Image:
    (For those of you without a PDF viewer [available below])


  • PDF File
    (Nicer looking, easier to print out, smaller file)

small picture of tiedown idea

Kevin Walsh created these CAD files of a modified version of the Du Bois tie down system:

  • DWG File
    (For those of you with a CAD system)


picture of tie-downs

Wing CAD Drawing

zipped DXF
 File picture of wing CAD file

Aileron Cut-Out Instructions

Joe Polenek had some issues cutting out his ailerons and asked me to write up instructions for cutting them correctly. I came up with some written instructions and Joe made some great drawings to illustrate the steps. These will ensure that the top and bottom cut lines align and meet, and give the correct shape with no interference. The first file is a PDF of the cutout process, and the second file is a historical record of why the plans are a bit confusing.

The third file is a table of aileron balancing using steel tubing and lead wire rather than a solid steel rod, with 3/8" tubing, and the fourth file is a table using 7/16" tubing

CHAPTER 20 - Wingletsnew.gif (1041 bytes)

CHAPTER 21 - Strakes

Rego Burger has an idea for a strake window with a protective cover. We had been kicking this idea around on the mailing list. Click on the image to see the full size version.

strake window idea


Jack Wilhelmson has provided a design for a Fuel Cap:

CHAPTER 22 - Electric/Avionics/Instruments

Ed Richards has provided an AutoCAD DWG drawing of his electrical schematics. They are extremely detailed and useful.


Rego Burger has provided this drawing of his:

Mode_C_tester_sm.gif (2737 bytes)


Landing Brake Safety Interlock:

I've created this wiring diagram for a Safety Interlock between the Landing Brake Actuator Switch (if you have an electrical Landing Brake Actuator, NOT a mechanical one) and the Throttle.  This interlock prevents takeoffs and go-rounds with the Landing Brake in the "Down" position - it will automatically retract the Landing Brake when the throttle is advanced to whatever position the builder would like - 1/2, 3/4, or full.

Here's how it works:

  • The standard actuator either moves the Landing Brake up or down based on the polarity of the power into the two wires.  A DPDT switch with center off (not necessary, but a good safety measure) is generally used swap polarity of the power going to the actuator.  The actuator has limit switches which turn it off when it reaches the ends of it's actuation range.
  • The Safety addition is to add another DPDT switch, actuated by Throttle position, that will automatically switch power to the LB actuator in the "UP" direction when the throttle is opened.  In this case, the standard DPDT reversing switch will have no effect.
  • When the Throttle DPDT switch is NOT in the "open" position, it shunts the power to the reversing switch in the normal manner, so that the LB can be lowered or raised manually
  • I've ordered some 15A DPDT heavy duty switches from Digikey.  I should be able to mount P/N CH326-ND near the throttle handle to perform the necessary task.
  • See:

    to get info on the actuator and mounting scheme.

Frank Johanson created a additional safety feature for the Interlock, involving using slightly different switches and a relay, with a few diodes.  This ensures that even if the throttle is retarded with the LB switch in the down position, the LB will NOT extend due to the throttle retardation without a reset of the LB switch to the up position before being put back into the down position.

This is revision 4 - the last two versions of the drawing had errors.  I had the top connection between the relay and the switch going from the common position on the switch to the wrong connection on the relay - it should have gone to the "Normally Closed" position, not the "Normally Open" position. I also had the diodes reversed, and I have clarified the nomenclature on the relay contacts and the motor wires, as well as inserted the "center off" position on the 4PDT switch.  Thanks to Paul Stowitts and Bill Theeringer for helping me out with my drawing errors.

CHAPTER 23 - Engine Installation

Kevin Walsh has created this full set of baffle drawings from accurate CAD files. They are adaptations of the Berkut baffles - they are NOT the stock COZY MKIV baffle design. They're available in either two PDF files or one DWG file.

CHAPTER 24 - Wheel Pants

Ed Richards has come up with this DXF drawing of the metal bracket used to mount the Featherlite wheel pants onto the landing gear.Once again, Doug Shepherd created the PDF file(s).


This is taken from the Central States Newsletter under the "fair use" doctrine.

air exhaust, air exhaust,
side viewMilton Matthews (MI) - I work in the Chrysler Corp. Jeep and truck department and recently came across a part that I installed on my Vari-Eze to exhaust air from the cabin. It is based on a rubber flap obtained from a Chrysler dealer (part number 3794032 24861-8-3).


  1. Cut a rectangular opening in the outside skin (4" x 4-1/2") as close to the rear of the fuselage as possible (Under the fuel strakes?) (see figure 1).
  2. Dish out an area 2-5/8" x 2" for the glass to glass bond. Lay up 2 plys of BID as shown in section A-A and allow to cure.
  3. Locate the rubber flap on the glass bond and drill two 3/16" holes to mount the flap. Cut a rectangular opening 1-1/2" x 2-1/2" in the glass to glass bond area (see fighre 1).
  4. The rubber flap is available from a Chrysler dealer. The rubber arrows snap into the 3/16" holes shown in section A-A.

 Editor note: You purists wanting a smooth exterior skin might consider this flap as an automatic valve and design an exterior cover to hide it. If the vent's back and is left open give due consideration to water drainage as nose down parking in the rain will turn your back seat into a pool.

Mark Beduhn supplied these drawings for Vortex Generators that he installed on both his Canard and Main Wing. He states that he lowered his approach speed by 10 kts. and only lost a couple of kts. on the top end.

Jim Springer has provided a drawing of the Matco Brake installation on a COZY MKIV gear leg strut.


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Copyright 1995 - 2021, All Rights Reserved, Marc J. Zeitlin

Last updated - February 13th, 2021 (Added Joe Polenek's Rudder Return Spring Install; Updated Perpendicular Belhorn Install)