PILOT Flight Check

partment to isolate a fire. This is more positive than turning off the fuel se- lector valve, which is located between the front seats. The shutoff valve is located on the far left side of the panel, just a couple finger-widths above the like-sized Instrumentation is neatly arranged in the Hawk XP, with the panel accommodating as much radio space as most IFR pilots would ever require. The Hawk XP's systems control quadrant below the instrument panel contains the elevator trim (left). cowl flap lever (right), and both the rudder trim and fuel selector valve (lower center). The microphone attaches to the quadrant center. With a 66-gallon useful fuel capacity in optional integral fuel cells, the Hawk XP offers a maximum 938-statute- mile range with 45-minute reserve. 800 ft 1,360 ft 870 fpm 133 kt (153 mph) 130 kt (150 mph) 122 kt (142 mph) 675 nm (776 sm) 723 nm (836 sm) 17,000 ft 53 kt (61 mph) 46 kt (53 mph) 620 ft 1,270 ft primer. Although Cessna has provided different-shaped knobs for each valve, their close location could make it pos- sible for a pilot to mistake the shutoff valve for the primer, especially in a darkened cockpit. Pilots accustomed to flying carbu- reted engines shouldn't have any trou- ble transitioning to the fuel-injected Hawk XP. The manual plunger-type primer is rarely used except in ex- tremely cold weather starts. The XP's auxiliary fuel pump, however, is a regular engine-start checklist item. The rocker-type fuel pump switch is split into red-yellow halves, indicating high- and low-pressure positions. The pump is used primarily for engine starting, with the high pressure side spring-loaded off. When the high pres- sure switch is held on, the low side automatically trips on. In the event of failure of the engine's manually driven fuel pump, the auxiliary fuel pump must immediately be held in the high position to reestablish fuel flow. It then is left in the low position until a landing can be made. The auxiliary fuel pump isn't used during letdown, landing or taxiing, because it would result in an exces- sively rich mixture during periods of reduced engine power. Operation with the pump on in these flight phases will result in a rough-running engine. Since, during start-up, the low pres- sure side automatically trips on when the high pressure is held on, the low side must be turned off manually. With mixture full rich and the master switch on for starting, the intake manifolds could become flooded if the engine is cranked with the auxiliary fuel pump accidentally left on. The XP is easy to taxi. Visibility through the 3600 vision windows is good, but the high wings dictate cross- ing active runways with caution since landing aircraft could be a little diffi- cult to see. Nosewheel steering is lim- ited to 10 degrees to either side of cen- ter, though braking extends the turn arc to 30 degrees either side. The before-takeoff checklist is rou- tine. The PILOT'S aircraft, however, had an inaccurate indicator on the roll-type elevator trim wheel on the lower in- strument panel post. The trim tab it- self could be easily seen out the rear windows, though, making it possible to position the tab for takeoff. Rudder trim is provided by a bun gee which connects the rudder control sys- tem to a trim lever also located on the lower center post. The system, which merely tension-cocks the rudder left or right, is easy to operate; detents pro- vide six nose-left and -right positions. A vertically adjustable cowl flap lever on the right side of the center post also provides detents for positive positioning of the single cowl flap lo- cated on the belly of the aircraft above the nose wheel. A minor irritant to us was the microphone cord which hangs in the way of the rudder trim and cowl flap levers. With the long-range fuel cells each m d·c';' tles' 36 ft 27 ft 2 in 8 ft 91/2 in 172 sq ft 14.71b/sq ft 4 108 in 391/2 in 48in 1,5411b 1,0171b 2,5581b 13.11b/hp Fuel capacity (standard) 52 gal (49 usable) Fuel capacity (long-range tanks) 68 gal (66 usable) Baggage capacity 200 Ib Performance Takeoff distance (ground roll) Takeoff over 50 ft Rate of climb Maximum level speed Normal cruise speed (80%) Economy cruise speed (70% ) Range, normal (45-min res) Range, economy (45-min res) Service ceiling Stall speed (clean) Stall speed (flaps down) Landing distance (ground roll) Landing over 50 ft DECEMBER 1978 I THE AOPA PILOT 37 Hawk XP brimming at their 33-gallon useful ca- pacity and two adults on board, 736ZZ was within 200 pounds of gross weight. The day was a beautiful 73°F, with II-- northwesterly winds at about 16 knots, light for Kansas where the winds blow wild. Our first takeoff was a normal one, with 10 degrees of flaps. This flap set- ting decreases the ground run by about five percent, according to the hand· book. With full throttle developing the maximum 2,600 rpm for takeoff, fuel flow was about 15 gallons per hour, as noted on the fuel flow gauge. During the ground roU, the XP's power advantage over the Skyhawk could be felt as the aircraft accelerated down the blacktop. Easing back the yoke at 56 knots lifted the nosewheel and the Hawk was soon airborne in the first quarter of the 3,800-foot runway. At best rate of climb speed (81 knots), the craft climbed skyward at just over 800 feet per minute (fpm). At sea level, the climb rate would be about 870 fpm, according to Cessna, an advantage of 100 feet per minute over the Skyhawk's sea level climb rate. Cook Airport, a 2,500-foot paved strip just southeast of Wichita, pro- vided The PILOT an opportunity to ex- plore Cessna's short-field pledges for the XP. In the pattern, the first notch of flaps could be lowered at 110 knots to begin slowing the airplane. This new flap extension speed is a hefty 25-knot increase over last year's model. A standard pattern was flown, with full 40 degrees of flaps lowered on mid- final, helping peg an approach speed of 70 knots. Skyhawk pilots might experi- ence a brief initial tendency, as we did, to reduce power a little too soon. Given the XP's gross weight advantage of 250 pounds over the Skyhawk, the XP's sink rate seems greater. Carrying a little power over the threshold and closing the throttle just prior to flare seemed to work out fine. \¥ith the nose- wheel held off the runway during roll- out, minimum braking was required. A short-field takeoff was set up with the recommended 10 degrees of flaps and full 2,600 rpm before brake re- lease. Holding a slightly tail-low atti- tude during the roll and then easing the Hawk off as soon as it would fly let us climb out at the best climb angle (60 knots). Fifty-foot obstacles that can loom larger and larger to pilots of some lesser-powered aircraft appear- ed to be dwarfs over the end of the runway. Placing the Hawk XP and the Sky- hawk at their respective 2,550-pound and 2,300-pound gross weights on ah airport with a theoretical pressure alti- tude of 6,000 feet and an 86°F temper- ature produces an interesting compari- son. The Hawk's ground roll of 1,565 feet would be only 20 feet better than the Skyhawk's, with the Hawk clearing a 50-foot obstacle in 2,765 feet, com- •••••••• The aerodynamic design of the Hawk XP has a long and successful lineage, traced to more than two decades ago with the introduction of Cessna's Model 172. That design, already incorporated in more than 30,000 Skyhawks, has been heralded as one of the most stable of any aircraft in its class or weight. The four-place Hawk XP is built at Cessna's Strother. Kan .• facility, where the Skyhawk and 152 models are also produced. The company is currently turning out an average of two Hawk XPs a day. pared to the Skyhawk's 2,895 feet. While both sets of figures appear very close, remember that the Hawk is carrying 250 more pounds of useful load. That's one more adult, 13 more gallons of fuel and a little more than an hour's range at cruise. In extremely high density altitude situations, a Hawk pilot should be able to get his payload of passengers and cargo out of most airports by simply trading off fuel ca- pacity. In a Skyhawk, the tradeoff could begin to eat into the payload. A stall series at 4,000 feet produced no surprises. The stall warning horn sounded between 10 and 5 knots above actual stall, which in the Hawk pro- duces only a slight buffeting. At our near gross weight of some 2,300 pounds, the XP stalled at 46 knots with wings level and full flaps; in a power-off 30° turn, stall speed was just above 50 knots. Keeping the ball cen- tered and continuing to hold back- pressure as the aircraft buffeted finally resulted in the nose pitching down lazily. Standard recovery technique was used with minimal altitude loss. At Strother Field south of Wichita, PILOT picked up a factory-new Hawk XP to examine its cross-country traits on a trip to Mattoon, Ill. Sh'other, in- cidentally, is where Cessna currently is turning out a combined 17 152s, Sky- hawks and Hawk XPs a day. Light surface winds were from 300 '- degrees and the temperature had warmed to 76°F as we flew N758DF off the rUllway and established an 80-knot climb speed. Climbing at about 800 fpm, our en route cruising altitude of 5,500 feet was reached in just under Eeven minutes. There was a long way to go to the XP's 17,000-foot service ceiling. Leaning at altitude according to the manual, 80% power was set up at 2,600 rpm and 23 inches of manifold pressure. At power settings above 70% , Cessna recommends using an optional DECEMBER 1978 I THE AOPA PilOT 39 Hawk XP Two wide cabin doors swing out to provide easy access to the Hawk XP cabin, which is roomy and comfortable. The Hawk XP's optional wet wings increase fuel capacity to a usable 33 gallons in each wing. Cruise range at 80% power and 6,000 feet is 675 nautical miles. =:1';11 exhaust gas temperature (EGT) gauge to lean the mixture to 50 degrees on the rich side of peak EGT. Continuous operation at peak EGT is authorized for power settings of 70% or less. Since Delta Foxtrot had less than two tach hours when she was whisked from her roost, Cessna asked that 80% power be used to break in the engine and ensure proper seating of the piston rings. With the aircraft properly leaned, the Hawk peppered along at 119 knots indicated airspeed. Though the EGT gauge could be used for leaning, it was somewhat erratic at times, with dra- matic needle fluctuations. At our pressure altitude of 5,500 feet and a 41°F outside air temperature, the true airspeed was 130 knots, agreeing with what the performance tables said we'd get. Fuel flow was 11 gallons per hour. By comparison, the Skyhawk 40 THE AOPA PilOT I DECEMBER 1978 • would develop a maximum 75% power at this altitude, for a true airspeed of 120 knots, while burning 8.4 gallons per hour. Best fuel economy at 70% power (2,600 rpm, 21 inches mp), with the mixture leaned to peak EGT, saved just over two gallons of fuel an hour in the Hawk, at seven knots less true air- speed. Well into the 438-nautical-mile trip, we dropped down to 3,500 feet beneath a scattered cloud deck east of the Mis- souri River to take in some of the color- ful Jack Frost nature palette below. A power setting of 2,500 rpm and 24 inches manifold pressure produced just under 80% power, with speed dropping only three knots from our original 130- knot TAS cruise at 5,500 feet, but with half-gallon-an-hour fuel savings. Three hours, thirty-four minutes into the trek, the Hawk winged into Coles County Memorial Airport at Mattoon, where a fill-up indicated that the fuel- flow rate gauge was accurate and that an average of just over 11.2 gallons per hour had been consumed since takeoff. The 23 usable gallons remaining in the tanks would have permitted another hour and fifteen minutes of flight, or 159 nautical miles at 126 knots true airspeed, with a 45-minute, or 8.5 gal- lon, reserve. The XP gave a quite comfortable ride, with the attractive fabric and vinyl standard front seats providing ample hip, shoulder, head and leg room. Adult rear-seat passengers, while treated to bountiful leg room, might get a little uncomfortable on a long trip since there's little lateral squirm room. But the sightseeing is great from back there, with wide, deep windows offer- ing an unobstructed view of the scenery . The noise level isn't unbearable in the Hawk XP, though the passenger door window did howl a bit where a section of the weatherstripping had pulled free. The pilot's door, which didn't close flush with the fuselage as did the other, no doubt added to a sligh tly higher noise level than a pilot might normally find. Cabin ventilation is good, with op- tional $165 high-speed blower and overhead outlets available. Heating the cabin, however, is another matter . Ducts carrying heated air from the en- gine compartment feed only into the front cabin at floor level. By the time the warm air reaches the rear occu- pants, it has cooled down considerably. The Hawk comes in three models: the basic Hawk XP at $33,950; the Hawk XP II (offering some factory- installed avionics and accessories), $37,200; and the Hawk XP II with Nav- Pac (even more avionics), $41,150. The extended-range fuel tanks are an op- tion at $575, while the 26-pound float- plane installation kit, exclusive of floats, rings in at $2,495. Extra goodies on both aircraft flown by The PILOT brought the average list price for the two to $48,600. For owners of Skyhawks and other carbureted-engine aircraft, the Hawk XP offers a natural step-up to increased performance, without the added sys- tems complexity and operating cost that other aircraft in that category sometimes demand. It is curious to note, however, that you can buy a 1979 Skyhawk II with Nav-Pac for $33,150, $800 less than the basic Hawk XP will set you back. Compara- tively, the basic 144-knot-cruise Sky- lane costs $39,995. Nevertheless, the blend of vener- able Skyhawk familiarity with an en- gine and constant-speed prop which produce a little extra oomph when it can be needed most, seems to be a winning combination in the Hawk XP. With some 892 Hawks having been delivered to date, many pilots appar- ently have found the XP's added per- formance factor over the Skyhawk worth the investment. 0