Flight Reports - COZY MARK IV

It gained wide acceptance as people got used to its unusual looks and were attracted to its exceptional efficiency. There was, however, a demand for an aircraft with more than two seats. Nat Puffer of Mesa, Arizona, the Cozy Mark IV designer, originally modified Rutan's Long-EZ to a side-by-side two plus one configuration called the Cozy 3. Later, demand for 4 seats led to Nat's Cozy Mark IV.

It uses the Lycoming 0-360 180 hp engine, has two rear seats, a thicker wing spar and larger wing area than the Cozy 3. Rutan agreed to provide Nat's company, Co-Z Development of Mesa, with a license agreement to sell plans that use Rutan's technology.

The Cozy's solid foam core composite design utilizes a hot-wire saw construction technique and is the simplest, least expensive four-place design on the market. Like most modern canard homebuilts, it is designed to be "stall resistant".

Mark Beduhn, the builder of our test aircraft, began working on his kit at 3:00 a.m. every morning before work for two years, worked alone, and finished his aircraft in 2,300 hours.

Nat Puffer sells Cozy plans, and directs his builders to suppliers. Many fast-build options are available. Website information is available at: www.cozyaircraft.com

I was sitting under the wing of my plane at EAA AirVenture '98 when Brien Seeley came by and introduced himself as a member of the CAFÉ Foundation. He said they were interested in testing a Cozy Mark IV, and he asked me to consider allowing them to use my plane. Brien explained that they would do a weight and balance on electronic scales, have a professional test pilot explore the flight envelope of the plane, and then publish the results in Sport Aviation. He then gave me a packet of information, and asked me to think about it. It didn't take me long to conclude that this was a unique opportunity.

The information that Brien gave me included instructions on building the wing cuffs that hold some sophisticated instruments to the wing of the plane. Although they didn't look too difficult to make, I decided to allow myself a couple of months, to make sure that I had enough time. I confirmed a test date with Brien, and then ordered the materials that I needed. It took me about three weeks to build the wing cuffs which I shipped to CAFE. I then got ready for the 1,600 nm trip from Conway, Arkansas to Santa Rosa, California. The weather for the trip was perfect, and I arrived on a Friday afternoon at around 3:00 p.m. The first thing that had to be done was to determine the empty weight of the plane. My Cozy was emptied, the fuel was drained, and we then rolled it on to the electronic scales which were built into the floor of the hangar. The scales are so sensitive that we had to close all of the doors and practically stop breathing while the measurements were taken. A laptop computer was attached to the scales so that the CG of the plane could be instantly calculated whenever the plane was being weighed. After the initial weight and CG. Were measured, the fuel truck came and topped off the tanks. After filling the tanks C.J. Stephens (the CAFE test pilot) and I went for a familiarization flight. Since C.J. has flown practically everything with wings, and also owned a VariEze for ten years, I did not expect it to take long for him to get used to my plane. I was correct. He seemed very comfortable with the plane after only a few minutes. We flew for a half hour or so, landed the plane, and rolled it back into the hangar. Several more CAFE volunteers had arrived while we were flying and immediately started working on the plane after we climbed out. Everyone had their assigned task. It was like watching a racing pit crew in action. The cowling was removed and numerous instruments were installed. A video camera and laptop computer were mounted in the cockpit for gathering data. The wing cuffs that I had built were attached to each wing, and the sensors were installed in them. At about 7:00 p.m. I went to the hotel, exhausted, but the CAFE people continued to work on the plane until around midnight. When I arrived back at the hangar on Saturday morning, C.J. was already on the third test flight. Every time he landed a flight parameter was changed. They changed either the weight, the CG or both. The intent was to test as much of the flight envelope as possible. Having the scale hooked up to a computer made these changes very quick and efficient. C.J. continued flying all day, and finished just after dark. On Sunday he flew two more times for his subjective analysis, and was done around 10:00 a.m. When the last flight was completed, the plane was swarmed by CAFE volunteers removing all of the instruments they had previously installed. By 2:00 p.m. the plane was back in its original condition and ready to go. Whew! A lot was accomplished in only a couple of days!

My experience with the CAFE Foundation was very positive. I met some very nice people and learned a lot about my plane. I consider myself very fortunate to have had my plane tested by this very professional group of volunteers. I would highly recommend that if you are ever offered this same opportunity, don't pass it up!

CAFE MEASURED PERFORMANCE, N494CZ
Propeller max. static RPM		2350 RPM
Vmax, TAS, 854' dens.alt., 1668 lb, 29.2", 2691 rpm, 12.9 gph		182.1/209.8 kt/mph
Stall speed, 1903 lb, 8" M.P., 1200 RPM, nosegear up, CAS		71.4 kt/82.3 mph
Stall speed, 1672 lb, 11" M.P., 1260 RPM, nosegear up, CAS		61.5 kt/70.9 mph
T.O. dist., 5 mph headwind, 71° F, 125 ft MSL, 1900 lb/1680 lb		1600 ft/960 ft
Liftoff speed, by Barograph, 1900 lb, CAS		71.7/82.6 kt/mph
Touchdown speed, Barograph, 1855 lb, CAS		79.4/91.5 kt/mph
Minimum sink rate, 1857 lb, 94 mph CAS, 108 mph TAS		641 fpm
Glide ratio, idle, 106 mph CAS, 116 mph TAS		14.25
Noise levels, ambient/idle/full power climb/75% cruise		62/81/92/96 dB
Peak CHT in climb, 90 kt, full power		491°F
Cowl exit air temp@491°F CHT, 58°F OAT		180°F

Cozy N494CZ Sample c.g.
Sample c.g.	Weight, lb	Arm	Moment
Main gear	1203.8	110.2	132644
Noeswheel	33.4	19.2	641
Pilot, front	170.0	59.0	10030
Co-pilot, front	170.0	59.0	10030
Passenger, rear	70.0	101.0	7070
Fuel,wing tanks full 51.7 gal.	310.4	104.5	32442
Oil, included 7 qt.	0.0	0.0	0
Nose weight	-57.9	19.2	-1111
Baggage, none	0.0	136.0	0
TOTALS	1899.7	100.9	191746
Datum: 113.9"fwd of rear wing/strake intersection
c.g. this flight, in.	100.9
c.g., % MAC	na
c.g., % aft of fwd limit	76%
Gross weight, lb	1900.0
Empty weight, lb	1179.3
Useful load, lb	720.7
Payload, lb, full fuel	410.3
Fuel capacity, gallons*	51.74
Empty weight c.g.	112.1
c.g. range, inches	97.5-102
c.g. range, % MAC	na
*as weighed by CAFE

Panel IAS, mph	CAS, mph CAFE Barograph #3
80.6	82.3
92.2	93.4
103.7	104.2
115.2	115.3
126.7	126.8
138.2	137.3
149.8	148.4
161.3	160.3
172.8	170.3
184.3	182.7
195.8	193.6

COZY MARK IV N494CZ Privately built and owned by Mark Beduhn Construction: Composite fiberglass and foam core. Equipment: Vision Micro engine monitor
SPECIFICATIONS
Empty weight/gross weight	1179.3 lb/1900 lb
Payload, full fuel	410.2 lb
Useful load	720.7 lb
ENGINE:
Engine make, model	Lycoming IO-360Ex, MB-1
Engine horsepower	180 BHP
Engine TBO	na
Engine RPM, maximum	2700 RPM
Man. Pressure, maximum	atmospheric
Turbine inlet, maximum	na
Cyl head temp., maximum	500× F
Oil pressure range	60 - 90 psi
Oil temp., maximum	245° F
Fuel pressure range, pump inlet	5 - 28psi
Weight of prop/spinner/crank	na
Induction system	Bendix RSA-5 fuel injection
Induction inlet area	6 sq in
Exhaust system	1 into 1, 4 separate pipes
Oil capacity, type, cooler	8 qt., 15W-50, Stewart-Warner cooler
Ignition system	1 Slick, 1 Lasar magnetos
Cooling system	Belly NCACA scoop, updraft
Cooling inlet area	50 sq in (stock cowl)
Cooling outlet area	100 sq in, fixed, no cowl flap
Propeller:	fixed pitch
Make	Performance 3-Bladed
Material	wood
Diameter/Pitch	64/76 in
Prop extension, length	8 in
Prop ground clearance, full fuel	13.5 in
Spinner diameter	11 in
Electrical system	12 V battery/35 amp alternator
Starter	lightweight Skytech starter 49-12pm
Fuel system	2 wing tanks - fuel injection
Fuel pump	engine driven pump, elect. boost pump
Fuel type	100 LL
Fuel capacity, by CAFE scales	51.74 gal
Fuel unusable	0.5 gal. each side
Flight control system	pitch-canard/ailerons on rear wing/rudders on winglets
Tire size, mains/nose	500 x 5 /4.00 x 4
Cabin Dimensions:
Seats	4
Cabin entry	side-hinged canopy over rear wing
Width at hips	36.5 in
Width at shoulders	39 in
Height, seat to headliner	37 in
Baggage capacity, rear cabin	27 in L x 26 in W x 24 in H
Baggage door size	rear wing strake pockets for small bags
Lift over height to baggage area	47.5 in
Rear baggage capacity	70 lbs
Step-up height to wing T.E.	26.5 in step/ 21" rail

KIT SUPPLIER Co-Z Development Corp. 2046 N. 63rd Place Mesa AZ 852115 602.981.6401	OWNER/BUILDER N494CZ Mark Beduhn 16 Tanglewood Drive Greenbrier AK

DESIGNER'S INFORMATION
Cost of airframe materials, no engine or inst.	$14,000
Plans sold to date	744
Number completed	35
Estimated hours to build, from prefab kits	2500
Prototype first flew	October, 1997
Normal empty wt. per Owner's Manual	1050 lb
Design gross weight, lb, Takeoff/Landing	2050/1900 lb
Recommended engine(s)	O-320 to O-360 Lycoming
Advice to builders:	No spins, abrupt maneuvers, or rough fieldoperation. Chandelles, laxy eights, steep turns ok.
CAFE FOUNDATION DATA, N494CZ
Wingspan	28.1 ft
Wing chord @ root/tip, Strake chords	41.5/21 and 93.5/41.5 in
Wing area	101.4 sq ft
Wing loading	18.7 lb/sq ft
Power loading	10.55 lb/hp
Span loading	67.6 lb/ft
Airfoil, main wing/canard	Modified Eppler from Long-Eze/Roncz 1145
Airfoil, design lift coefficient	0.2
Airfoil, thickness to chord ratio	15 %
Aspect ratio, wing area	7.26:1
Wing incidence	0 °
Thrust line incidence, crankshaft	na
Wing dihedral	0 °
Wing taper ratio, root/tip,	+.75 °/-.25 °=1 ° Total
Wing twist or washout	1.5°
Wing sweep	23°
Steering	Differential braking, castoring nosewhee
Landing gear	Tricycle, retractable nosegear (elect.)
Canard span/area/taper ratio/aspect ratio	12 .1 ft/13.1 sq ft/1.0/11.2
Canard chord	13 in
Elevator: total span	54 in
Elevator chord	4 in
Winglet span/area incl. rudder	57 in x 20 in (ea.)/228 sq in
Winglet chord: average	20 in
Rudder: average span	50 in
Rudder chord, average	6 in
Ailerons: span/average chord, each	71.3 in/6.5/4.2 in
Canard incidence	0 °
Total length	17 ft
Height, static with full fuel	7.9 ft
Minimum turning circle	18.5 ft
Main gear track	6.5 ft
Wheelbase, nosewheel to main gear	7 ft
Acceleration Limits per factory:	+3.8/-1 g
Airspeeds per Owner's Manual
Never exceed, Vne	190 kt/219 mph
Maneuvering, Va	120 kt/138 mph
Best angle of climb, Vx	80 kt/92 mph
Best rate of climb, Vy	90 kt/104 mph
Stall, clean, 1900 lb GW, Vs	na
Stall, dirty, 1900 lb, GW, Vso	na
Gear operation/extended, Vge	150 kt/173 mph
Airbrake max. extension	85 kt/ 98 mph
Not approved for spins

Flight Test Details
Seven flights were made over the course of a weekend beginning October 9, 1998, all during day VFR conditions. A Flowscan fuel flow transducer was used for the gph determinations and was calibrated by measuring the weight of fuel burned on each flight. A PropTach digital tachometer was mounted on the fuselage belly to look aftward through the prop disc. Performance data flights were conducted with pilot and flight engineer aboard and flying qualities were evaluated with solo flights using an analog G meter and Brooklyn Tool & Machine Co., Inc. NJ hand-held stick force gauge.

Cruise flight data was obtained with the wingtip CAFE Barograph (#3) mounted on a wing cuff with a dummy barograph and cuff mounted on the opposite wing. These were correlated with the panel airspeed indicator to produce the airspeed correction table shown here. Our data suggest that Vy is 105 mph CAS and Vx is 87 mph CAS. Stalls were performed with the nosegear retracted. 56 pounds of nose ballast was used to obtain forward CG.

Cowl exit temp is a function of the OAT & CHT and is a measure of the efficiency with which the cooling system removes heat from the hot engine. This can be expressed as the temp rise relative to the hottest CHT observed during climb:

The CAFE scales were used to determine the moment/arm of the aircraft's fuel. This was found to be 104.5ý aft of datum rather than the 103.0ý described in Owner's Manual.

IMPORTANT NOTICE
Every effort has been made to obtain the most accurate information possible. The data are presented as measured and are subject to errors from a variety of sources. Any reproduction, sale, republication, or other use of the whole or any part of this report without the consent of the Experimental Aircraft Association and the CAFE Foundation is strictly prohibited. Reprints of this report may be obtained by writing to: Sport Aviation, EAA, P.O. Box 3086, Oshkosh, WI. 54903-3086.

ACKNOWLEDGEMENTS
This work was supported in part by FAA Research Grant Number 95-G-037. The CAFE Foundation gratefully acknowledges the assistance of Anne Seeley, EAA Chapter 124, and the Sonoma County Airport FAA Control Tower staff.

SPONSORS
Experimental Aircraft Association
Federal Aviation Administration
Aircraft Spruce & Specialty Co.
Aerospace Welding Minneapolis, Inc.
Cessna Aircraft Corporation
Fluke Corporation
B&C Specialty Company
Engineered Software "PowerDraw"
Bourns & Son Signs
AeroLogic's Personal Skunk Works Software

COMPARATIVE AIRCRAFT FLIGHT EFFICIENCY, INC.
The CAFE Foundation:
A Non Profit, All Volunteer, Tax-exempt
Educational Foundation
4370 Raymonde Way
Santa Rosa, CA 95404
FAX 707/544-2734
Aircraft Test Facility, Santa Rosa Airport
707/545-CAFE (hangar, message)
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