Two Top Trainers

In addition to installing an Avco Lycoming O-235-L2C engine, Wichita did a fair amount of modifying the older 150 airframe and appendages:

• A new wrap-round engine cowling now gives increased access during servicing periods.
• Conical wingtips are now optional, the conventional wingtips encourage students to fly properly and not take unfair advantages, while not jeopardising safety factors.
• A 28-volt electrical system is now standard, giving greater tolerance to learners’ fingers on starter motors.

Internal cosmetics include a pre-select flap lever, further thought to occupants’ anatomies in redesigned seating, and flush window latches that don’t obtrude into shoulder space in what is admittedly a small cabin.

Other mods announced by Wichita include a one-piece nose cap, spinner and bulkhead design which do away with prop spacing; engine baffling incorporated into the cowling design; a standard oil cooler for more uniform temperatures under all conditions; a long-life muffler system, and claimed quieter operating conditions.

This latter achievement has been engineered by virtue of the high-compression 110hp engine, full dyna focal engine mounts, plus a gullwing prop design.

Greater speed, range, rate of climb (sea level datum), service ceiling and take-off performance are all part of Cessna’s new 152 attraction, over the old 150 series.

Most pilots and enthusiasts are already more than conversant with the small Cessnas, but AADR has included the 152 Aerobat in this issue to give something for the purist to chew on when considering why the little Cessna has such a firm foothold in Australasia’s training market.

First pilots have in many cases opted for a 150 or 152 when considering primary purchase, after training on the type. And from all accounts, the 152 is holding its own against strong competition from the Tomahawk and Grumman singles machines with undoubted efficiency and operational appeal.

A standard Cessna 152 Aerobat was supplied for our test by Rex Aviation, of Bankstown, with Rex Flight School instructor Roger Kerville riding shotgun in the little machine, VH-IWX.

A conventional workout plus limited aerobatics proved the point claimed by Cessna, that it wasn’t easy to build a replacement for the 150 – but they made it.

The 152 retains all the ladylike attributes of the 150 and is stern enough to complain when mishandled but compassionate to a degree that it helps the student get out of most jams he or she has unconsciously engineered.

At the same time, the minuscule-width cockpit has been designed to cater for maximum comfort should the pilot and passenger decide to travel the full 575 nautical miles when their steed is fitted with 37. 5 gallons of US usable tankage.

Externally, the 152 Aerobat is basically similar to her older sister; optional conical tips were fitted to the 152 under test.

Internally, new features include contoured seating plus an increased legroom provision; verniers on throttle and mixture controls, and a 30-degree max. flap extension (Wichita research came up with the statement that any more than 30 degrees of flap could put student pilots in a hazardous situation at some stage or other).

India Victor Whisky was fitted with a standard “school” panel, to wit:

Left section (top, I to r); ASI, artificial horizon, altimeter centre; turn and bank, gyro, VSI, G-meter. bottom; ·· fuel gauges, oil pressure and temperature.

Centre section; comm.

Right section; rpm and ammeter.

Master switch, mags, lighting, flap lever and circuit breakers dominate the lower sub-sections, with the trim wheel.

Priming before start-up on a cool morning proved something of an interesting experiment. Following two reverse pull-throughs on the 69in fixed pitch prop, two squirts of prime were decided upon.

On pulling out the priming plunger for the first intake, I became the recipient of a generous dose of 100 octane up my left shirt sleeve.

.A more cautious approach on the return push and second intake ensured the fuel going the right way . . .

Ground handling the 152 presents no problem; traditional Cessna visibility is apparent, there is negligible waddle, braking is positive and progressive and footloads are light.

Noise level is average; Cessna claims external noise level is five decibels less than 1980 FAA and ICAO requirements.

Runup is minimal, looking for mag drops at 1700 rpm, setting flap if required, and conducting routine cockpit drill.

The ground temperature was a moderate +16C on rollout. With two pob and three-quarter standard tanks, weight was about 200Ib below the max weight of 167016. The wind was light.

Acceleration was almost sprightly on the rollout, with speed building up satisfyingly during a run expressing low torque swing. With nil flap, Vr was assessed at 60 knots IAS, lift-off at 65kts IAS.

Initial roc hit 1000fpm before settling down to a more realistic 700fpm with 2350rpm and 70kts IAS, temperature dropping to +14C en route to 2000ft.

Indifferent met resulted in a cruise mode being set up at 2000ft, using 2350 rpm. With OAT now at +12C, a fast 115kts IAS was recorded initially, settling back after trimming to a still-respectable 110kts IAS. Cruise at 8000ft, 75 per cent power, is booked at 106kts IAS in the Manual.

In cruise mode, visibility, ventilation, noise levels and cockpit occupant comfort were all assessed as above average.

Control surfaces displayed command to a marked degree, encouraging proper use by both low-time pilots and others who need a wash-and-brush-up on proper flying techniques.

Ailerons are powerful enough to pick up a downgoing wing at low speed and thus speed up the airflow to a point above the stall.

Stall themselves are manoeuvres to be worked on, to make them obvious. Clean stalls are booked at 48kts IAS, dirty stalls at 43kts IAS. Both result in nodding descents, with wing drop being picked up by either rudder or aileron – the latter being applied delicately.

Entry speeds for chandelles, lazy eights and steep turns are standard at 95kts IAS, with slow deceleration recommended for entry into spins and stalls (except whip stalls).

Spin recovery takes up to 1. 25 turns. This, however, is a variable factor.

G-forces (flaps up) are an ample +4. 4 to -1. 76. Flaps down, +3. 5.

The· manual, on manoeuvre entry speeds, states that higher speeds can be used on condition that no abrupt control use is exercised.

A landing at Haxton Park formed part of this evaluation. Downwind was made at an ample 100kts IAS, with the base being negotiated at a whisker under 80kts IAS (Vfe is booked at 85kts IAS, and 20 degrees was hung out to stay astern of another light aircraft making a wide circuit).

The approach was a comfortable 65kts with about 1000rpm on, with a slight crosswind. The booked distance of 475ft would have been handsomely bettered aftertouch, but the test aircraft was allowed to run to the next intersection.

The 152 was adequately stable at approach speed, wiJ,h only delicate aileron and rudder needed to correct for a waffle at about 200ft.

No final correction was applied for drift, to check trueness in crosswind conditions. The test aircraft wandered only slightly, with the offside wheel about four feet left of the centreline on touch.

Takeoff was accomplished in a shorter distance than the manual’s 725ft – as had been the initial breakout from Bankstown.

Random notes culled from the manual en route to Bankstown at the end of a happy re-association with Cessna’s littlest one, include the following:

Max speed (s/I), 110kts IAS.

Cruise, 75 per cent power at 8000ft, 107 IAS.

Vne, 149kts IAS.

Vno, 111kts IA. S.

Va 1670lbs, 104kts AIS.

1500lbs, 98kts IAS.

1350lbs, 93kts IAS.

Vfe, 85kts IAS.

Glide; flaps down 60kts IAS. Flaps up, 65kts IAS.

There seems little doubt, from the numbers of Cessna 150s and 152s in Australia, that Rex has minimum worries about marketing the 152 in the short term.

The aircraft is ideal for training, initial PPL purchase and general runabout work. Station duties are almost invariably performed by this slow-capable high-wing machine on jobs where downward vision is paramount.

This isn’t to say that you cannot see upwards in the 152. Tinted ceiling panels can be fitted – and used in crowded circuit areas to ensure that the classic situation of a high-wing aircraft ascending under a low-wing machine doesn’t arise.

As in all evaluations, the philosophy of the test pilot/writer is to find out what’s right rather than what is wrong; to this end, mention might be made of only one item obviously wrong – and probably a matter of detailing rather than production.

In the test aircraft, it was pretty obvious that if one wanted to switch off the fuel at the selector lever, more than a normal amount of burrowing would have been needed to unearth it from deep in the carpet pile.

Piper Tomahawk

An honest aeroplane is a label hard to pin on modern trainers-cum-runabouts; the Piper Aircraft Corporation has come within a whisker of achieving this desirable soubriquet with their PA-38-112 – the little Tomahawk.

A lot of midnight oil was burnt at Lock Haven before the production of this tiny two-place T-tail was given full throttle. The task given to the Tomahawk design team was basically to bring about the gestation of a training aircraft capable of producing textbook reactions to specific circumstances.

What was rolled out of the hangar was a type as near as possible to the ideal training machine – the Tomahawk as marketed in Australasia by Ansett General Aviation.

Traditional dedication to Cessna’s little 150 (and now the 152) made it hard to make an initial dent in the school market. But at the time of writing this evaluation, Ansett GA reports that up to 27 are now in service at flight schools all over the nation.

Five more were awaiting delivery after being contained from the US to Bankstown and assembled in the Piper hangars.

About 13 clubs and schools in Australia now specify training by T’hawk; the Air Training Centre at Archerfield the Gold Coast Aero Club, the Royal Aero Clubs of New South Wales and Victoria, NASA at Cessnock, the Albury Air Centre, plus the Darwin Aero, and Cliff Brown’s Flight School and the Albany club in WA.

Lock Haven (and Ansett General Aviation) told the Tomahawk development story before we evaluated this attractive little school hack.

The design team did the right thing from the outset; they had a poll conducted among 10,000 professional instructors to see what likes and “wants” came out of the boiling pot.

Plenty of comfort and elbow room; low noise levels; lively and fun to fly; optimum vision; tough construction to take all the unorthodox treatment handed out by students; and ease of service to ensure the machine is online when needed.

What eventually emerged was an aircraft conventional enough about the fuselage (semi-monocoque with riveted skin) but with wings sporting NASA’s GA (WA)-1 aerofoil section. This Whitcomb adaptation has a high aspect ratio, an excellent lift/drag ratio and in the Tomahawk’s case sports thermoplastic tips.

Thermoplastics and fibreglass are now used in tips engine cowling and non-structural parts.

The now familiar T-tail was added for several reasons; together with the gentle-stall Whitcomb wing it enhances low-speed handling qualities, gives authority to specific manoeuvres and also end-plates washout plus enhancing rudder effectiveness in spin training.

The power plant chosen to urge Piper’s Tomahawk was a Lycoming 0-235-L2C rated at 112hp at 2600rpm, housed beneath an easy-access cowling and dyna focal insulated to minimise vibration.

A fixed-pitch Sensenich 72-in diameter prop was hung on the end.

Tankage was assessed at 30 galls US usable. The landing gear was selected as interchangeable single-leaf steel springs for mains, and an air-oil nose wheel shocker.

Cockpit design, rehashed several times en route to the production model has been cleaned up to what is perhaps the ultimate in a light trimer type.

A 42-inch wide cabin gives ample room between both seats to avoid elbowing. manoeuvres, while visibility is nothing less than excellent for all planes.

A strong rollover structure takes care of the occupants in all but high-impact accidents.

The Tomahawk selected for this test bore the serial number indicating that it was the 628th machine to roll out of Lock Haven in 1979. Ansett General Aviation’s Keith Robey flew the seat during the evaluation.

Among the mods fitted to the Tomahawk since it first saw the light of day has been the fitting of an additional burble strip on the inboard leading edges, to make stalls more authentic and complete.

External and internal finish on this particular aircraft, which had only testing and acceptance hours on the VDO was first class.

Sensible drain points are another good feature of Piper’s Tomahawk. Checking the Cleveland wheels and brake assemblies made it obvious that the machine has a wide stance – 10ft between main wheels.

Checking elevator travel and condition during pre-flight isn’t as hard as it looks, although there’s nearly 8. 5ft/2. 63 metres from terra firma to fin top. The Tomahawk is balanced (and light) enough to enable the checker to bear down on the rear fuselage, gently touch the ground with the Tomahawk’s tail bumper and then do his/her checking.

Inside the cabin via a walkway and low sill, the aircraft’s accommodation design thought is at once apparent. Seats are comfortable and rise as forward travel is initiated. Control accessibility is ideal school stuff, complete with Piper’s traditional manual flap control ·and what could be the only bone of contention – the throttle control, in quadrant rather than easier-to-manage push-pull configuration.

The friction nut placed below and between throttle and mixture levers and directly under the direct-readout fuel selector lever (which points to the tank in use), seemed to need careful study before the pilot finds out which way to turn the knob for friction ON or OFF..

The panel, from left to right, top to bottom rows, is Clock; ASI; AH; vacuum gauge; altimeter; nav/comm and VDO. Middle row; turn co-ordinator; gyro; VSI. Bottom row; tac!i0rneter with electrical switches beneath; carb heat; park brake below panel, usual Piper push-button ON style on the lever; fuel gauges on power console; primer; temp and pressure gauges; circuit breakers.

Airspeed indicator and rpm gauges are colour-arced to lend point to the following limitations: Va (design manoeuvring speed), 167016, 103kts IAS; at 127716, 90kts IAS. Vne 138kts IAS; Vno 110kts IAS. Vfe 89kts IAS. Max continuous is redlined at 2600rpm.

The startup is standard drill; as this was the first flight of the day and the ground temperature was a frigid +6C – plus the fact that this honest little aircraft’s engine has no accelerator pump so no amount of throttle-pumping will induce fuel – three pumps of prime were given before switching on.

The warmup is given as between 800 and 1200rpm for not more than four minutes in cold weather.

Ground handling presented a non-problem. A minimum turning radius of 26ft, pivot point to wingtip, makes negotiating often crowded flight school lines a thing of ease. There was no suggestion of waddling from the 10+ft undercard track, and braking was comfortably efficient. Nosewheel travel 30 degrees on either side of the centre added to the ground manoeuvrability.

Runup is conducted at 1700rpm. At this stage, it was apparent the Tomahawk is a fairly quiet aircraft – not too many decibels but what there are are harsh-sounding units.

Take-off was made with nil flap, with wind light/var, and +8 showing on the OAT gauge. The aircraft was at that time just about on gross of 1670lb.

Torque was low during the run and Vr noted at SSkts IAS (manual recommendation is eased back on the stick at 53), and liftoff made at a shade under 60kts IAS by a gentle backpressure. The authoritative elevators will pop you. off the ground if a definite jerk is made. The test aicraft flew itself off with a gentle back-stick and accelerated briskly to the best rate of climb speed of 70kts IAS.

The initial roc was 900fpm, but this settled back to the manual rate of 700fpm at 2350rpm. Fuel pump OFF, the Tomahawk’s rate of climb bettered book speed by at least five knots – and stayed that way during climbout.

In cruise phase at 4000ft, in an intermittent chop, the Tomahawk made good as TAS of 112 knots at 2350rpm, a truly satisfying setting. In this and all other modes, the aircraft’s control response was true, with general stability being dynamic.

A marked nose-down attitude is achieved in the cruise. This, coupled with the high aspect ratio wing, should make initial navexes a high-visibility operation for the student.

Moderate and steep turns produced n9 vices, the roll rate being brisk without achieving the apprehensively quick stage.

Stalls in clean condition, the manual lists stall at 48 knots. This was matched during the flaps-up stall evaluation and arrived at with both airframe buffet and gentle pitching. Dirty, the aircraft stalled at 45kts IAS with 30 degrees of flap lowered, bettering the book by two knots.

Wing drop was picked up with an aileron in both cases, although a rudder can be used. Recovery is quick and clean, although to be fair a fully-developed stall hass not made.

The test aircraft was cleared in the Utility category for spins, lazy eights and chandelles.

Spin entry is made from a power-off stall, with full back stick and hard into-spin rudder. The Tomahawk will spin enthusiastically and truly at about 360 degrees/1. 5-second rate and stop say the manual, between half a turn to one and a half turn 1 s after recovery control input after more than one full turn.

In the evaluation spins, three turns were made before· opposite rudder was applied, full forward stick was applied after the opposite rudder hit the stop.

Relaxation of forward pressure was needed to stop an excessive nose-down attitude.

The aircraft recovery in less than one full turn in every case . . . A broad height loss is about 1000ft for one full turn, six turns 2500ft.

Gliding is docile in the Tomahawk; about 70kts IAS is listed as ideal. Turns were accomplished to the near-steep angle at this speed with no vices apparent.

A brace of touch-and-go’s at Hoxton Park proved the point that the Tomahawk can be side-slipped in with ease when needed.

Base leg on a normal circuit is accomplished between 80 and 75kts IAS, with the first notch of flap where necessary. Finals usually mean 70 knots on the clock, with the flap coming down early with little pitch change apparent.

In the test landings, the back trim was applied progressively until it was on the rear stop. With power coming back from 1800 to about 1500 on short finals, speed over the fence should be 70 or just under, and flare made about 55 knots IAS.

A gentle flare usually holds the Tomahawk in a slightly nose-up attitude until it sinks through the ground effect. Touch is gentle, thanks to the steel-spring mains and an authoritative elevator.

Which brings one to the bone of contention; high wing or low wing for honest landings during training? There really isn’t all that much difference in technique, providing the student is taught to fly and not cheat . . .

Evaluating Cessna and Piper trainers naturally brings up the $64,000 question – which one takes pride of place?

Assuming that flight schools are the bull’s-eye of both Australian distributors, there really is very little to choose from and the ultimate choice must surely rest with CFls.

Both little aircraft are powered by the same engine, have the same fuel needs and TBOs – and both need to be flown every inch of the way in the correct manner.

The Tomahawk is the more honest aircraft in some respects, giving textbook reactions to specific circumstances and manoeuvres. The little 152, however, is perhaps more forgiving to the first hesitant steps of flying training.

Encapsulating the types, here is a rundown of the various salient points for comparison: