Texas Taildragger 152

But, over the years since Cessna sacrificed utility for flying simplicity, several companies have developed modification packages to put these aeroplanes’ little wheel back at the right end. Of these, the Texas Taildragger conversion is probably the best known.

The process might be time-consuming, but is not obviously complex. A rectangular structural bulkhead box has to be built across the cabin floor, ahead of the seats and inboard of the lower strut fittings, to take the main gear loads. The main gear legs are then removed from their original position, shifted 74cm forward and attached to this box, while the nose-leg, its steering links and associated structure are removed from the engine mounts.

Down at the tail, some reinforcement is added, and the suspension springs of one of four alternate tailwheels are bolted in place.

Steering linkages and springs are attached to the rudder cables, and the final touches are completed by fitting a fairing, and plating over the original main leg attach points. There is

Cessna 152s are not noted for their sprightly performance, but this one was perceptibly more energetic than most.

”a ten-pound weight improvement, the aeroplane’s centre of gravity stays the same, and it is not necessary to remove any original skin for this conversion. Speed increases of up to 10kt are claimed, with standard prop clearance improved by 18cm.

In 1978 our delightful test aircraft started life as a standard Wichita-built Cessna 152, but it was converted to tailwheel configuration in 1985. Later, after exportation to New Zealand in 1994, it had to operate from abbreviated country airstrips, so its aerodynamics were enhanced by a Short Take-off and Landing (STOL) package, and its engine’s power was increased.

Since then this little Cessna crossed the Tasman to end up the personal runabout of Tony Rikkers, CFI and chief pilot of the Aeroplane Company, based at Jandakot. Being rightly proud of his unique 152, he invited me to fly it with him.

Given most pilots’ familiarity with the standard Cessna 152, I shall merely concentrate on the differences.

For a start, the whole aeroplane is a little closer to the ground than the original, with its trailing-edge lower still. This can be a trap for the unwary who don’t fancy a cookie-cutter pattern of diamonds across their face from the flaps and ailerons. On the other hand, it does make refuelling easier, and allows close inspection of the Horton STOL modifications.

The very low tail makes pre-flighting the tailplane, elevator, fin and rudder much simpler, putting even the rotating beacon within easy reach. Unfortunately, inspecting the tailwheel, its spring and the steering mechanism is a little more difficult, since they are partly obscured by the low-set tailplane; in addition, a fibreglass fairing encloses the suspension spring. These components are worthy of careful examination though, because both steering spring and tailspring breakage are quite common. Either could result in loss of control, while the latter can also cause significant rudder damage when the unrestrained tailwheel and its spiky auxiliary components bounce around, denting and puncturing everything within range.

This example has a pneumatic Maule tailwheel – the cheapest of four alternatives, but the most maintenance-intensive. Connected to the rudder actuating linkage by chains and springs, it is designed to steer through 20 degrees either side of neutral. When that angle is exceeded, a cam disengages a pin in the mechanism, allowing the wheel to castor freely.

Unfortunately, the wear and deterioration of normal service gradually reduce the wheel’s useful steering angle, allowing it to disengage at smaller deflections, with a consequent tendency to ‘go bush’ at the slightest provocation.

Think it’s just another Cessna 152? Take a second look.

”A latent fault of all steerable tailwheels with such a disconnect mechanism (but one particularly applying to the Maule wheel) is that during landing, when you use significant rudder inputs to push off the drift, it can be only too easy to simultaneously (but inadvertently) disconnect the steering mechanism. There is little you can do about this, other than to be aware of the tendency, and to be quick with differential brake as your secondary source of directional control. The standard, tapered, tubular spring main gear legs are unchanged from the original, although their position on the fuselage sides seemed to make them a little wider splayed. Being undamped, they might be slightly harder to control than a damped undercarriage leg, but since so many tailwheelers do not have damped main suspension, I suspected this would not be an issue. Indeed, it is always a useful training feature that trainers are more difficult than theaeroplanes successful students might go on to fly.

One aspect worth checking that would be important if you were considering buying one of these aeroplanes (or, indeed, any tailwheeler) is the main wheel alignment. A few degrees of toe-out, or worse, the tiniest bit of toe-in, can seriously affect directional control. This is not such a problem on grass or gravel, but could turn this little beauty into a beast on a hard runway. Rectification is simple, by inserting tapered shims between the brake back-plate and the axle stub.

Perhaps this is the source of the occasional uncomplimentary comment to be found about tailwheelers on internet chat rooms, a dubious source of information at the best of times. Personally I suspect that most loudmouthed internet criticism of taildraggers comes from ‘pilots’ who, having bought a tailwheeler cheaply, attempted to teach themselves how to fly it.

Up at the front, there is little to differentiate this Sparrow Hawk engine conversion from the standard Lycoming O-235 – even the baffles looked barely changed – but I suspect a direct comparison of similar models might reveal subtle disparities. I did wonder if the Texas Taildragger’s tail-down stance affected the dipstick reading, but I found no mention in the STC paperwork of modifying this.

Even with the longer Sensenich propeller, this tailwheel modification should increase prop clearance by 14cm, but to me it appeared quite tight in the level-flight takeoff attitude.

The Sparrow Hawk power package

Lycoming’s O-235 is a willing and economical little engine with a generous 2000 hour TBO, but nobody would call this 110hp (82kW) motor powerful.

So a small company in Washington State set about increasing its performance.

By replacing the normal 8. 5-to-one compression-ratio pistons with a high-compression 9. 7-to-one set, and advancing the spark timing to 25 degrees before top dead centre, they have been able to wring 125hp (93kW) from the same basic engine, without any weight penalty.

Replacing the original 175cm McCauley propeller with a 183cm Sensenich prop of 132, 137 or 142cm pitch, and increasing maximum continuous rpm to 2800 (which, they assure customers, is Lycoming’s original certified rev limit) enables this extra power to give a useful thrust increase.

Inevitably, there are tradeoffs. More power generates more waste heat, so the modification includes better baffles to enhance cooling. Higher compression pistons require higher-octane fuel, so 100/130 Avgas is a requirement.

Increased power also means greater fuel consumption. Air Mods provide a couple of simple graphs, but recommend that owners assess and implement their own decrements to range and endurance.

Usually, running an engine at higher rpm and increased power output for long periods will reduce that engine’s life expectancy, but Air Mods even claim that ‘wear limits seem to be less than found in the stock engine at TBO. ’Getting into the aeroplane was slightly easier than usual, despite the fact the gear-leg steps have gone, and mostly thanks to its lower sill height, although there was a slight tendency for the doors to swing shut unaided.

The new transverse structural box beneath our knees was noticeable, but not obtrusive; otherwise I could see little internal change. One aspect that was a definite improvement was the slight recline imparted to our seats, which made them more comfortable for me.

I had expected forward vision to be impaired by the upturned nose, but although the far end of the cowling was definitely higher than usual, it didn’t protrude significantly into the view ahead, and it was not necessary to weave while taxying, as it is in so many other tailwheelers. There was a slight lost motion to the steering around the neutral point, but this is not unusual with Maule tailwheels, and some experienced pilots advocate that there should be a little slack in the system, to reduce directional sensitivity.

The brakes worked as you would expect, and the main gear legs were far enough forward for there to be no tendency for the tail to lift, even under quite heavy braking. The wide track and long wheelbase made this little aeroplane feel very stable on the ground.

Cessna 152s are not noted for their sprightly performance, but this one was perceptibly more energetic than most.

It didn’t exactly leap forwards, but it did accelerate significantly better than a standard one, while emitting a most un- 152-like roar from its engine and howl from its prop! Within a couple of seconds, and with a fairly hefty push, full forward yoke lifted our tail into a near-level attitude. I didn’t notice the need for any more rudder than in a standard nosewheeler. After running a couple of hundred metres like this, we floated into the air at around 65kt. On one early attempt, I tried hauling her off at just 50kt, but that only resulted in my dragging our tailwheel along the ground before staggering into the air with the stall warner bleating. Using 10 degrees of flap, we flew from a 600m grass runway with a 5kt headwind and in a temperature of 20 degrees Celsius, and even that takeoff took little more than half its length. I was not able to time our climb rate, but it seemed rather better than a standard 152’s 715ft/min, indeed we appeared to reach 1000ft in less than a minute.

Because of the need for good cooling in this high power engine installation, Air Mods recommend a speed of 75kt for prolonged full-power climbs.

Control was good in all axes, and there was none of the anticipated reduction in either pitch or yaw stability due to the aeroplane’s increased power or its larger propeller disc. Perhaps this was partly thanks to the removal of itsde-stabilising nose-wheel.

As expected, this little yellow Texas Rose is also slightly faster than a standard 152. It will gallop along at 122kt, burning 30 litres per hour, although Tony usually flies at a more economical 2400rpm, to give himself a nice, round 100kt, burning 23 litres/hr.

This one has the mid-range 137m pitch (or ‘cruise’) propeller. Alternatives are the fine pitch 132cm ‘climb’ prop or the 142cm coarse prop.

In all other respects this 152’s handling was just like any other’s: predictable, easy

The Horton STOL kit

Do you want to fly your aeroplane more slowly, so you can get into and out of shorter airstrips? Or do you just want bigger safety margins while flying at normal speeds? Then a STOL kit might be just what you need.

Big, mass-production companies like Cessna and Piper build aeroplanes down to a competitive price. They are not interested in wringing out the last drop of performance from their airframes, merely in maximising their profits. So, if you want to improve your Cessna’s wing, you go to one of several American companies who specialise in enhancing production aeroplanes’ aerodynamics. Some sell ‘high-speed’ packages, but the majority concentrate on lower-end performance. Horton is one of the best-known of the latter.

Their kit includes a new, more cambered leading-edge cuff, so the wing keeps flying at higher angles of attack, thus reducing stalling speeds.

Drooped wing-tips are claimed to reduce vortex drag and improve lowspeed roll control, while full-chord fences at the aileron/flap intersection are aimed at reducing spanwise airflow at high angles of attack.

Aileron gap seals similarly improve low-speed aerodynamics, and can also reduce cruise drag.

Horton make no numerical claims for their kit, although it clearly improves low speed performance. There may be a tiny reduction in top speed, but the only obvious disadvantage seems to be the requirement to fit a placard prohibiting intentional spins. to fly and exhibiting all the same vices and virtues. Regrettably, this model was not an Aerobat, for I suspect its more powerful engine coupled with the tailwheel conversion would significantly improve an Aerobat’s normally limited capability.

TEXAS TAILDRAGGER
CESSNA 152

Technical Specs
Powerplant
One normally aspirated,
four cylinder, horizontally
opposed Sparrow Hawk
Lycoming O-235-N2C,
producing 125hp (93kW)
at 2800rpm. TBO 2400
hrs. Prop: 183cm diameter,
two bladed, all-metal
fixed pitch Sensenich S72
CK S6-0-54.
Performance
(Manufacturer’s quoted)
Sea level Vne 149kt
Max speed (MSL) 105kt
75% cruise (8000ft) 110kt
Stall, full flap 40kt
Weights
Equipped 539kg
Max takeoff 758kg
Standard fuel 96 litres
Load factors +4.4/-1.76g
Dimensions
Wing span 9.98m
Wing area 5.49m2
Length 7.35m
Height 2.59m
Seating two

Thanks to the Horton hardware, this Cessna not only stalls at significantly lower speeds than the original, but also exhibits no sign of a wing-drop, however hard you push it. Indeed, with full flap, even power-off, the indicated stall speed was right off the clock, below both the lowest numeral (40kt) and even the lowest calibration, at 35. Position error clearly plays its part here, but nevertheless, these are impressive numbers.

The slow stall and very tractable low speed handling show up again during the approach.

Tony recommended I make my first, full-flap attempt at 60kt, reducing to 55 over the threshold, but this resulted in a long float before achieving the nose-high threepoint attitude. During my second approach I let the speed trickle right back to 50 over the hedge (with a dribble of power) and this resulted in much less float and a creditably short landing run of under 200m.

Tony reckons he can land in a couple of fuselage lengths by balancing drag against power on the back of the drag curve and coming in with the airspeed near its bottom stops, but I was not game to try this without more practice. Nevertheless, it would be only too easy, in this capable aeroplane, to sneak into a field you could never fly out of again! I noticed that, despite our very low airspeed, we still had good, quick control responses in pitch, roll and yaw, right down to the touchdown, which was once again off the clock. At this speed the yoke is fully out of the panel, a situation few 152 drivers would normally encounter.

The tailwheel undercarriage capably absorbed our gentle touchdowns and directional control was easy (although we were operating off grass). Like most Maule tailwheels, Tony admitted this one has a tendency to ‘shimmy’ on harder surfaces. I suggested his apparent shimmy symptoms were actually caused by the disengaged tailwheel rotating rapidly around its vertical axis, a common Maule tailwheel problem caused by the release of its locking pin when making quick rudder corrections while accurately aligning the aeroplane with the centreline immediately before touchdown.

Whatever its cause, we did not encounter the phenomenon.

Altogether I found this a smashing little aeroplane, and would love to have flown her for longer. She was both more fun and more satisfying to fly than a standard Cessna, and I think she’s nicer to look at, too.