Ken had built a Glasair and used the construction techniques from that experience to develop the Express. The aeronautical design for the Express was largely performed by a team working with Ken Wheeler.

The kit supply gradually caught up to the healthy demand for this aircraft and, in 1989, Jerry Sjostrand became one of the 300 who had bought kits to build the Express. Jerry has since become an expert in this aircraft and crafted the beautiful version which serves as the subject of this report, N360EZ, Serial # SJ2146. There are reportedly 30 examples of the Express now completed and licensed.

MODIFICATIONS

The kit manufacturer information lists a building time of 2,000 hours for the Wheeler. Jerry estimated his building time at 5,000 hours but added that his included extraordinary attention to finish work inside and out. That effort was evident everywhere in the superb finish on N360EZ.

Jerry was a pioneer builder who, working from incomplete plans and drawings, actually created much of the documentation used by subsequent builders. He also invented many modifications during the course of his project, some of which are now valued improvements incorporatated by other Express builders. These include creating a baggage door/escape hatch on the right rear fuselage that was engineered with help from Chuck Ritchie at Scaled Composites. Precise Flight speed brakes as used on the Mooney and a center control stick with left-sided throttle quadrant were also part of Jerry's redesign. N360EZ has a Slick magneto on the left and a Lightspeed Engineering capacitive discharge ignition unit on the right side. The Lightspeed unit involves two four pound ignition modules in place of a conventional magneto.

The lower cowl was modified to allow the use of a 3-blade non-extended hub propeller from the Piper Arrow. An option of dual brake pedals was also installed.

Jerry designed the seats for quick removal and created a nifty cabin layout allowing three seats and a 74" long litter/baggage floor area underneath which are two large storage bays. These bays were covered by carpeted graphite floor panels (see photo).

N360EZ's cooling baffles were modified to become a completely enclosed 'doghouse' cold air plenum on top of the engine.

A small vent door on top of the cabin door's leading edge was added to provide a strong blast of fresh air to the front occupants upon engine start. A second NACA inlet vent on the right side of the fuselage above the wing was installed for cabin airflow in cruise but is ineffective in climb, according to Jerry.

This Express had a Century 2000S autopilot with altitude hold. The 27 pound radio stack included dual nav-coms, a Narco GPS/nav/glideslope/ localizer unit as well as DME and marker beacon receivers. The fuel system included a fuel return line to each fuel tank as used routinely with the Continental fuel injection system. Jerry commented that if he were to do it over again he would not have included the elaborate radio and instrument equipment.

HISTORY OF DEVELOPMENT

Early in the aircraft's development the Wheeler Express demonstrator crashed in Santa Monica, California, reportedly due to an engine failure. The landing gear and wing damage was severe. However, the structural integrity of the fuselage and cabin observed after that crash and the lack of injury to the crew apparently had a favorable effect upon the company, serving to attest to the strength of the design. "People began calling it an escape capsule," Jerry said.

A second crash involving impact at high speed and at a steep angle to the ground killed all four occupants and was labeled by the NTSB as "pilot error". This occurred just prior to Oshkosh 1990. It led to a severe contraction in sales eventually prompting Ken Wheeler to enter bankruptcy.

Meanwhile, a group of about 17 owners developed a variant of the Express initially known as the Arriga. This variation of the aircraft had the same wing and fuselage but a 13' span horizontal stabilizer with 40% more wetted area than the Express' 10' stabilizer. The Arriga tail retained some of the sweepback of the Express tail, but abandoned the cruciform tail configuration and used a conventional low-set horizontal tail. This larger tail was developed to solve some alleged problems with the cruciform tail on the Express. The cruciform tail was studied with videotaped investigations of their air flow using vortex generators and tuft tests. These were performed by a former Boeing engineer, Paul Robertson, of Arlington, WA with a goal of certification.

The Express kit business was purchased by Dave Ulrich in Redmond, OR, who took over in 1992. He carried on the business for three years as Express Design, Inc., tooling up to sell complete kits for both the Express and the Arriga. He renamed the Arriga, calling it the Series 90, and developed a conversion kit to allow Express owners to graft on the larger tail of the Series 90. The company was again sold in late 1996 to the current owners.

NEW COMPANY

The third and current owners of the design are two Express builders, Larry Olson and Paul Fagerstrom, in Olympia, WA. Now known as Express Aircraft Company, they hold the rights to both the Express and the Series 90 and have plans to furnish complete kits for these aircraft by April 1998. The kits will include all the pre-molded skins, hardware and engine mount --everything except engine, prop, avionics and paint. The structure will continue to be made of vinyl ester resin-impregnated E-glass with polyurethane foam as the sandwich core. The wing spar comes already bonded to one of the wing skins. Engine options have included the 6 cylinder 360 Continental and the lightweight Lycoming 540 series. A new engine option under development will allow use of the Continental IO-550. A kit to allow converting the cruciform to the Series 90 tail is being developed to attach to their shared common area of the fuselage.

There are currently several Express builders in other countries including France, Luxembourg and Switzerland.

FLIGHT TEST DETAILS

Six of the eight CAFE test flights were performed at gross weight. Weather conditions were favorable in all of the flights excepting Flight 7, which was marred by turbulence.

Barograph #3 was used on a wing cuff mount and was compared to CAFE Barograph #1 mounted in the cabin and connected to the stock aircraft pitot static system using "T" fittings to allow the panel airspeed and altimeter to indicate their normal readings. These three airspeed system's data appear in the calibration table in this report. Compensation was made for the drag of the wing cuffs in determining the cruise speeds published here.

The initial climb tests were conducted using Jerry's recommended value of 70 kts (panel) as Vy. This produced a markedly high CHT and oil temperature and the climb had to be aborted. During the peak temperatures of this climb, a temp probe, shielded against radiant heating and located just inside the cowl exit, reached a reading of 234*F. The CAFE Digital Acquisition Device and its probes survived this temperature. However, the Slick magneto coil of the left mag failed shortly thereafter.

After an intense work session to quickly diagnose the magneto problem, Jerry and some of the CAFE team were able to fly to Navajo Aviation in Concord and obtain a replacement coil on Saturday night from Mike Becker, their mechanic. Mike had been driving home from the Concord Airport with his children when his beeper advised of CAFE's desperate cry for help. He returned to the airport to meet our crew, installing the new coil for them on the spot. "No charge for the mag coil," said Mike, "just ship me a replacement when you're done testing the Express!"

Subsequently, extensive efforts were made to determine Vy and Vx for this aircraft, and these were found to be 98 and 75 kts, respectively, on the aircraft's instrument panel airspeed indicator. These correspond to 116 and 88 mph CAS, respectively. At these higher speeds, climb cooling was adequate and the maximum mpg, glide ratio and endurance were demonstrated.

The fuel flow data was obtained using the CAFE Foundation's calibrated flow transducer.

The subjective flying qualities evaluation was flown at a CG located 21.5% aft of the forward CG limit at a takeoff weight of 2551 lbs.

--Brien A. Seeley, President

FLYING QUALITIES REPORT

EXPRESS N360EZ

BY C.J. STEPHENS - CAFE FOUNDATION TEST PILOT

Wheeler Express, N360EZ, was of superb construction and perfect finish. The owner, Jerry Sjostrand, had created his own personal touches in many areas. These were well thought out and constructed with very high quality materials.

During my familiarization walk around and detailed inspection of the Express, I was impressed with the smooth flowing lines of the design that blend the various aerodynamic surfaces together. It had a normal, yet sleek appearance, with a moderate sweep back of the tail surfaces. There was a sturdy fixed step to aid in stepping up onto the wing walk. All placards and decals on the airplane were of exceptional quality.

ACCOMMODATIONS

One interesting feature on this design was the very large entrance door. The door is on the right side of the cabin, hinged at the top and measures 48" wide x 34" high. The two front seats were electrically operated to slide forward and aft at an angle such that it raised a person with shorter legs and lowered (as it moved back) for longer legged individuals. It was a very clever and simple design adapting electric motors from an automotive application. The single control stick was located between the two front seats, a modification of the stock control system which allowed the plane to be flown from either side equally well. The throttle quadrant, however, was on the left cabin wall in a position only available to the pilot in the left seat. The control movement felt quite comfortable and natural when operated from either seat.

One very nice and unusual feature of the aircraft design was the tremendous amount of leg room in the back seats. It measured 74" from the back of the front seats to the baggage compartment bulkhead. The owner had even built a litter type of installation that could be used with a sleeping bag giving a full 6 ft. 2 in. place for two people to sleep once the two back seats were removed. The amount of room available in the rear seat was reminiscent of some of the earlier airplanes such as a Stinson Station Wagon or a Beechcraft Staggerwing.

The 15" x 18" baggage door was purposely designed to be large enough to crawl through for cabin exit were the aircraft to become inverted in an accident -- a very commendable idea for any light aircraft. A reliable inside door opening lever was installed to complement the flush external door lever.

COCKPIT LAYOUT

The cockpit had a full compliment of electronic equipment with full VFR systems plus a limited IFR capability. This cockpit was laid out with all of the amenities required to make flying fun. Other cockpit features included cabin heater, defog, cowl flap and ample vents for cabin cooling air.

One item that was of concern to me was the cabin door locking system. It had a single lever to engage both of the hold down locks, but the lever was exposed to and just above the co-pilot's knee in such a way that, with cockpit movement or turbulence, upward motion of the knee could inadvertently open the entrance door. This could cause a sudden dangerous and destructive loss of the door on an otherwise normal flight and should be revised to prevent that possibility.

The sturdy instrument glare shield had two grasp handles cut into it for assistance with entrance and exit from the cockpit. This was a helpful feature, since cockpit entrance required stepping on the seats and maneuvering across the right seat and past the control stick before being able to slide into position.

The engine instrumentation installed, a Vision Micro Systems package, provided adequate information for all aspects of flight.

GROUND HANDLING

When pushing backwards with the provided tow bar, care was needed to prevent reverse castoring of the nose wheel. Without a good grip on the tow bar, there was a strong tendency for the nosewheel to flip backwards when backing up.

Fueling of the Express was normal through a fueling port near each wing tip. The two tanks were separate and could be fed with a right/left/off valve from the cockpit to manage fuel and maintain lateral balance during flight. The latter was found to be important because the aircraft had no aileron trim mechanism

Total capacity of the fuel system was 92 gallons. By our estimates that amount of fuel would be enough to leave Santa Rosa, CA and fly nonstop to Chicago. However, since many pilots routinely take off with full fuel tanks for local flights, the impressive tankage of the Express tends to create unnecessarily high takeoff weights producing sluggish performance.

Engine operation with the cabin door open required caution to prevent damage to the door hinges. The door was large and the propwash seemed to affect it unless it was held in a steady position manually. On warm sunny days, with the door closed, the cabin seemed to heat up rapidly due to the great window area. Once the engine was started, an electrically operated vent located centrally above the windshield helped offset the low volume of cabin airflow. Taxiing was easy with the use of differential braking. Field of view over the nose and in all directions was excellent during ground operations.

TAKE OFF AND CLIMB

The pre-takeoff checks were conventional in every respect including the checking of an electronic ignition that had been installed in place of the right magneto. The suggested takeoff flap setting was easily obtained by depressing an aileron fully and matching the flaps to the position of that aileron. The flaps could be easily seen from the cockpit negating the requirement for a flap position indicator. Takeoff trim was set to the appropriate settings by the use of a light "T" showing the position of the two tabs. The electric elevator and rudder trims were operated by a hat switch mounted on the top of the stick grip and the position was reflected on the "T". It was difficult for me to get used to operating the rudder trim with right and left thumb motion of a switch that, on most airplanes, is used for the aileron trim.

I am always impressed at how smoothly these 6-cylinder engines feel when compared to the four cylinder engines. Prior to adding the power for takeoff I watched the ailerons and operated the stick to ensure that I would find center stick position at lift-off. This seemed especially important with the stick being in an unfamiliar position at the center of the airplane. With all of the preflight checks completed, I was ready to experience flight with the Express.

TAKEOFF IMPRESSIONS

The manifold pressure gauge came right up to indicate 30.1 inches, with an actual rpm of 2,780. The acceleration was good considering the operating weight (maximum gross weight of 2,895 lbs.) of the airplane. The Express tracked straight down the runway during acceleration to the owner's recommended takeoff speed of 65 kts on the panel (88 mph CAS) and followed with a smooth and comfortable liftoff. Once safely airborne, the flaps were retracted which resulted in a mild settling before re-establishing the climb.

Initially a climb at published Vy (78 kts. on the panel airspeed indicator) was attempted. However, due to a low rate of climb and a steady increase in cylinder temperatures, a modified Vy was used for testing. The airplane seemed to climb much better when maintaining 95 kts. IAS. During these climbs at the higher IAS the cylinder temperatures remained below the red line, provided the cowl flaps were open and the mixture was left full rich. The owner had indicated, as we confirmed, that the engine was very sensitive to any leaning and it was recommended that no leaning be accomplished below 9,000' during climbs.

DYNAMIC STABILITY

The natural damping qualities were examined by introducing control doublets about an axis and then observing the tendency and reaction when returning to normal flight. Each axis was explored with the stick fixed and with the stick free to learn of the difference in damping quality generated from the control itself.

Pitch damping was deadbeat in both stick fixed and stick free modes, indicating a strong pitch dynamic stability. In yaw displacement, the aircraft showed low damping with both the rudder free and with the rudder fixed. It would overshoot four to five times before returning to steady conditions. This low directional stability was evidenced later in other flight regimes.

MANEUVERING STABILITY

Stick forces were measured while maneuvering in both clean and flaps down configuration. During the measurements the aircraft felt stable and stick forces built up as the G force increased. All of the information gathered indicates a good handling airplane about the lateral axis. Due to a G meter malfunction, the three G data is not available. Data collection was not attempted beyond three Gs since the aircraft had not previously been flown to that G limit. Note the graphed results of these tests.

SPIRAL STABILITY

Roll stability was observed by establishing a trimmed level turn of 15 degrees bank and releasing the controls. This airplane exhibited no tendency to either rollout or to increase the bank for periods of up to 30 seconds, thereby demonstrating neutral spiral stability.

ROLL DUE TO YAW

The roll due to yaw was examined by banking to hold a heading while progressively increasing the rudder input at 120 kts. panel airspeed. The airplane showed a normal amount of dihedral effect with an increasing amount of bank required as the rudder input was increased. However, near the end of the rudder input, during left rudder application, the airplane entered an uncommanded pitch down attitude without yaw recovery in spite of neutralizing the rudder. See discussion under "Problem areas."

ADVERSE YAW

Adverse yaw was sampled by observing the heading hesitation (or initial reversal) upon input of aileron without any coordinating rudder input (feet on the floor). The Wheeler tended to yaw opposite to the aileron input by 15 degrees with the right aileron depressed and only 2 degrees with the left aileron depressed.

STATIC LONGITUDINAL STABILITY

At 7,500 ft. altitude the airplane was trimmed to "hands off" at 150 kts. Without retrimming, measurements were taken of the stick force required to hold level flight at each 10 kt increment of all attainable airspeeds. The graph shows the results of these samples.

ROLL RATES/FORCES

The roll rate and stick forces were measured using the handheld stick force gauge in flight and a stop watch during replay of the video tape. At 140 kts. the stick force measured 25 lbs to attain full deflection. Generally the feel of the stick forces was very comfortable and normal, although at above 150 kts IAS the ailerons became noticeably harder to deflect. The roll rates shown below include the time to accelerate, rather than the sustained roll rate. Full aileron deflection was used to establish the roll and maintained during the 120 degrees change in bank angle.

STALLS

The stall characteristics of the airplane were sampled at various gross weights, CG and flap settings. The stall was preceded by noticeable aerodynamic buffet occurring at 5-7 kts. above the actual stall. When the stall occurred, the airplane would simply lose lift and allow the nose to drop slowly just prior to the stick being nearly full aft. Following 1 G level clean stalls the airplane would produce an uncommanded right yaw with inadequate elevator control until significant airspeed (85 kts. panel) had been regained.

A very nice electrically operated speed brake similar to that used on Mooneys was installed in the top of the wing at about mid-span and mid-chord. A panel mounted on/off switch was used to activate the speed brake to the fully out or fully retracted position. It was effective and could be activated at any airspeed without causing any noticeable pitch change. From stable, trimmed level flight at 130 kts., the speed brake deployment would produce a 400 fpm rate of descent. That is an expression of the drag from the speed brake alone since all other energy values were held constant. Stalls with the speed brakes deployed were uneventful and occurred at virtually the same airspeeds as without the brakes.

TRAFFIC PATTERNS/ LANDINGS

The Wheeler handled nicely in coordinated flight in the traffic pattern with a very low work load for the pilot. The simple cockpit layout, fixed landing gear, and excellent engine system left the pilot free to deal with other traffic, pattern management and radio communications. The field of view during letdown and turns was also very good. On flaring, touch down and control were comfortable and straight forward using both the flaps up and flaps down configurations.

CONCLUSIONS

The Express has an outstanding appearance with sleek, modernistic lines. In my opinion, the development of its handling qualities needs to be continued as outlined above to fully realize the design's potential and ensure a safe and predictable airplane.