Return to: Cozy MKIV Information

Return to: 2004 COZY Forum

2004 COZY Forum

Note: The first part of the answer (labeled MJZ) was my off the cuff answer at the forum.  The "EATF" part was "enhanced" by Wayne Hicks, using a larger data set than that found in between my ears.

Q: What are the acceptable engine choices for the Cozy MKIV?
A: MJZ: The recommended engine choices are the Lycoming O-360 and O-320 series of engines, ranging from 150 HP to 200 HP. The 320's are a bit on the light side, but a few folks have been very successful with them, and a couple have installed constant speed props. The O-360 is far more common, however. There are a number of folks that are installing converted automobile engines, mainly Mazda 13B rotaries and Subarus (both 4 cylinder and 6 cylinder). A small number of these have been successful for a short time period, and they show a great deal of promise, but it will take some time before the technology is proven for general usage.

Enhanced After the Fact: The Lycoming O-360 A-series is the recommended engine.  The Cozy is designed to use certified, 4-cylinder Lycoming engines from 160 to 180 horsepower, with dynafocal mounting, weighing 255 to 265 dry (no accessories).  The engines meeting these guidelines are the O-320 D series and the O-360 A series.  These engines are readily available and provide excellent performance and reliability.  Use of larger, certified engines is not recommended as they can exceed the weight limitations and have adverse effects on the weight and balance of the aircraft (causes aft center of gravity issues).  There are several builders who are installing auto engines even though auto engines are not recommended.  Initial costs for the engine are usually lower, but the installation time requires more effort.

Q: What about using the Continental TSIO-360 engine?
A: MJZ: What about it? Oh, there is one person that I know of that is installing one of these on his aircraft, with some substantial modifications. However, this plane is probably a couple of years or more from completion, so there is no data on the suitability of this engine for COZY usage. Hopefully it will be successful and open another avenue to COZY builders.

Enhanced After the Fact: The TSIO-360 engine weighs considerably more than the recommended Lycoming engine.  The Continental engine puts more weight aft and adversely affects the aircraft’s weight and balance.  Also, the Cozy provides updraft cooling from its NACA scoop.  While the Lycoming and Continental engines were manufactured as downdraft-cooled engines, the Continental engine runs hotter in the updraft configuration than does the Lycoming.

Q: Is the Cozy’s wing sweep the same as the Long-EZ ?
A: MJZ: Yes. The COZY family of aircraft are very similar to the Long-EZ aircraft, and share the same wing planform, sweep and size. They are, of course, structurally different, due to the different gross weights of the aircraft. The Vari-EZ has a very different wing shape and sweep from both the Long-EZ and the COZY.

Enhanced After the Fact: The COZY's wing span is a tad bit longer due to the Cozy’s wider fuselage.  The Cozy main wings have thicker spar caps and an additional ply on the top skin to add strength. 

Q: Has anyone tried installing flow fences on the Cozy ?
A: MJZ: I don't know of anyone that has installed fences on a COZY. I do know that they've been tried on Long-EZ's, but without the same success as on Vari-EZ's. I only know of one person that says that they've had success with the fences on a Long, and many that have seen no difference.

Enhanced After the Fact: Flow fences are flat plates shaped like triangles and installed vertically on the wing trailing edges near the ailerons.  They were made popular for the Vari-Eze by speed guru Klaus Savier.  The flow fences help reduce span-wise flow on aft-swept wings and they’ve been found to be very effective on the Vari-Eze.  Long-EZ drivers who’ve installed the fences haven’t found them to be as effective since the wings on the Long-EZ (and Cozy) aren’t swept aft as much as the Vari-Eze.  Some Long-EZ pilots with flow fences have reported better aileron response at low speeds.

Q: How many Cozies are at Oshkosh?
A: MJZ: I counted at least 17 Cozies (Classics, III’s and IV’s), including two former Grand Champion aircraft -Tim Merrill's MKIV, and Todd Morgan's III.  There are 6 in the Homebuilt Camping area, 3 in the main vendor area (Nat's, Tim's, and Nat's prototype III), 6 in the canard parking area, one in the hangars on the other side of the field, and one in the "previous champions" area in the front lines.

Enhanced After the Fact: If you want to see canard aircraft of all types, the most popular fly-in for Cozies and canard aircraft in general is the Rough River Fly-In, held each year in early October at Falls-of-Rough, Kentucky.  See for more details.

Q: What are the legal implications of signing the builder’s agreement in the beginning of the plans?
A: MJZ: Since I'm not a lawyer, nor do I play one on TV, I'm going to refrain from trying to answer that question, because I'd be making up the answer (just like I did with the rest of this presentation).

Enhanced After the Fact: By signing the legal agreement, you are acknowledging that the Cozy name and the technical information contained in the plans is property of Co-Z Development Corporation (now Aircraft Spruce) and that you will build only one plane with that set of plans.

Return to: Cozy MKIV Information

Return to: 2004 COZY Forum

Copyright © 2004, All Rights Reserved, Marc J. Zeitlin

Last Updated: - February 11, 2007