Flight test: Sud Est Alouette II
- Credit: NA
Predictable and vice-free ? although very thirsty ? the dependable Alouette’s handling would suit a low-time pilot | Words: Pat Malone - Photos: Keith Wilson
Seventy years ago the French aviation company Sud Est designed and built a helicopter called the Alouette, and it was a bit of a dog.
The celebrated test pilot Jean Boulet wrung an impressive performance out of the prototype when he set a world closed-circuit distance record of 675nm, but the company knew it was in a blind alley?such oddities as twin tail rotors mounted on a V-shaped tail, and the lack of puff from a 200hp Salmson piston engine, meant that this particular Alouette never went into production.
So Sud Est decided to do something really radical. They kept the powertrain and discarded almost everything else, and most importantly they decided they were going to make their old dog into the first production helicopter in the world with a turbine engine.
At the time, this was far from a no-brainer. Turbines were temperamental, used lots of fuel and had short lives and greedy maintenance appetites, and they were treated with suspicion by right-thinking engineers. But Sud Est had to take a leap of faith to make their Alouette fly, and they decided to risk it.
They found what they needed in the premises of a Polish refugee called Josef Sydlowski, who'd been working in Germany but had fled Nazi-era anti-semitism and taken his engineering genius to a little town called Saint-Pé-de-Bigorre in southern France.
After the German invasion he had further removed himself to Switzerland. His company, which he called Turbomeca, ticked over during the occupation, and when the unpleasantness was over Sydlowski went back and began to develop turbine engines.
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The marriage of Sud Est's airframe with Sydlowski's engine?an iteration he called the Artouste?created a phenomenon. The SE 3130 Alouette II made its first flight in 1955 and went on to become one of the best-selling light helicopters ever made.
In production for twenty years, it was adopted by armies and air forces all over the world, had some success in the civilian field, set and broke innumerable records and achieved the ultimate accolade when the Americans asked to produce it under licence; Republic Aviation made a handful, but they never really took off in the States.
The Army Air Corps in the UK bought seventeen and, although the machine was largely used for observation, liaison and training, several forces hung weapons on it, including anti-tank missiles and homing torpedoes.
One of its most successful spin-offs was the SA315B Lama, a beefed-up beast with exceptional hot and high performance. In 1972?again with Jean Boulet at the stick?it set a helicopter altitude record of 40,814 feet, which stands today. When Boulet reduced power the engine flamed out, so he set another record for the longest autorotation.
In the civilian world the helicopter has been put to everything from VIP transport to crop-spraying. Of the 1,300 Alouettes of all types built, there are said to be several dozen still in operation around the world.
They've long been eclipsed by more modern machinery?the Aerospatiale Gazelle was their immediate successor, Sud Est having been absorbed into Aerospatiale?but they are kept aloft by enthusiastic owners and pilots who don't mind a bit of noise and having to grease nipples and fill the tank every five minutes.
One such is Warren Davies, proud owner of N297CJ, which he keeps on a farm near his home in Alcester, Warwickshire.
Warren is a long-time fixed-wing pilot who used to race a Beech Baron and fly aerobatic gliders. He got his helicopter licence in 2000 and bought an R22 in which he used to bravely commute to the Midlands from the Isle of Man in two and a quarter hours, much of it obviously over water.
He kept G-KUKI for only nine months and continued his commuting in fixed-wings, but he's always been looking for something a bit different and when a friend showed him details of the Alouette II his interest was piqued.
"I'd never even seen an Alouette," he said. "But the spec looked good, and what was especially interesting was the price?£90,000, with a spare engine thrown in. That's about what a run-out R44 would cost, and when you think you'd pay well into six figures of money just for a Gazelle engine, it looks very attractive."
The Alouette II was owned by Steve Atherton, a Yorkshire-based collector of Aerospatiale products, particularly Gazelles, who had found himself with one too many. Manufactured in 1963, it had flown for most of its life with the German Army Aviation Corps, the Heeresflieger, before being transferred to the Portuguese military in 1981.
It was later sold to a civilian owner and put on the French register. After passing through the hands of several Frenchmen it was sold to the UK, placed on the N-register and kept at Redhill. It came to Steve Atherton in time for him to fly it to France for the sixtieth anniversary celebrations of the Alouette in France in 2015. With a couple of sparkling Gazelles in his hangar Steve wasn't flying N297CJ much, and was happy to let it go to a good home.
The Alouette II looks like the front end of a Gazelle stuck onto a section of Bailey bridge, with a big?very big?fuel tank in the middle and a little engine popped on top. It sits very low on really businesslike skids and is clearly hewn from proper girders.
It is in fact the front end of a Gazelle; its successor took the cabin unmodified from the Alouette. The tail trellis is of aluminium tubing filled with pressurised nitrogen; there are two tell-tales that change colour if the nitrogen pressure drops, in which case you'd wisely suspect a crack.
The doors are huge, running almost the entire length of the cabin, and with the fuselage sitting so low it must be the easiest light helicopter in the world to climb into. Below the main rotor gearbox is a truly humungous bathtub of a fuel tank which is said to hold 580 litres of Jet-A1.
Warren thinks it's actually only 575, but given that the helicopter burns through 180 litres an hour even at a nice sensible cruise setting, you need something that holds a lot. The Artouste engine was designed to run on almost anything that would burn, the idea being that in wartime you could land and siphon off whatever was available.
The blades have a light alloy spar and are filled with synthetic resin foam, and they can be folded for ease of storage.
Warren believes they've been fixed in place all the aircraft's life, and even though the folding exercise is said to be quite simple?just pull out a couple of pins outboard of the drag dampers?he wouldn't dream of trying to fold them. As well as the dampers, the head also features stout spacing cables.
There are sight glasses everywhere you'd expect to find oil, and topping off the various fillers, something that must be done regularly, is not a big job?they're all unobstructed and easy to get at.
At the bottom, just behind the cabin, you can see the control runs turning up to the rotor mast, and the wheel that's activated by a push-rod from the pedals; around the wheel is a dual cable that runs through a series of guides to the tail rotor pitch change mechanism.
Around the jetpipe there's a heater sleeve connected to the cabin by a seriously big piping system that goes up hill and down dale before connecting to internal overhead distributors. A helicopter with so much Perspex would need an efficient heater for demisting on damp days, but the weight must be significant?couldn't they find another way?
I suppose with a 530hp engine hauling a helicopter that weighs almost a tonne empty, a bagatelle like this matters less… On the side of the fuselage is a small handle that turns the heater from 'purge' to 'on'. The engine is supposed to be started in 'purge' mode, so if you're on your own, you're going to have your hands full switching on the heater.
The tail rotor drive shaft runs along the top of the boom through four intermediate bearings, each with a grease nipple. A lot of greasing needs to be done on this machine, and given that helicopters do what they do, it gets spread liberally about.
The tail rotor pitch change mechanism is activated by a screw-thread arrangement around which the pedal cable runs, and there's a gearbox that needs to be kept topped off with oil. The tail rotor blades flap independently over a surprisingly large arc, and there are two horizontal stabilisers of neutral airfoil section.
There's no vertical stabiliser but there's a large steel loop below the boom to protect the tail. Given the low-slung nature of the helicopter I was particularly conscious not to catch the guard by flaring too low.
Those massive doors contributed to the versatility of the helicopter in service?you can get a stretcher across the back, or several pairs of skis.
There are two catches to hold the doors open, and they're released by small handles that fall easily to hand when you're in the driver's seat?unlike the door handles themselves, for which you must reach way, way back behind you.
View is fabulous all round, although the door frame is at eye level and I found that I couldn't formate on the camera ship without leaning forward or back, so you'd have to be conscious of a blank spot.
The controls are where you'd expect, with the pedals being adjustable by turning over the foot bar. The cyclic on CJ has a couple of redundant switches that might once have pickled a load or even fired a TOW missile, but all that works now is the PTT.
The binnacle is authentic 1960s, although a subsidiary panel in which an artificial horizon was once set now houses an 8.33 radio. At the top of the main panel you've got a big red fuel flow light that comes on when you're demanding too much of the engine and thus overpitching.
There are warning lights for transmission and engine oil pressure, fuel pressure and fuel filter restriction. At top left is the ASI, with a 105kt redline, VSI next to it, and rotor and engine RPM gauge at top right.
Next row is, on the left, combined Turbine Outlet Temperature (TOT), engine oil pressure and temperature; altimeter; and collective pitch indicator, with a red line at 14.5 degrees. You can heave the lever through this to nineteen degrees in extremis, but you'll certainly be dicing with the fuel flow warning light.
On the bottom, below the rotor brake, there are electrical and air pressure monitors, plus a fuel gauge which, Warren points out not inaccurately, acts like a rev counter in reverse. Interestingly, there's no way you can dip the tank, so you'd best watch the stuff going in.
At the bottom of all this there's a guarded 'start' button, and three toggle switches for fuel boost, genny and batt, with associated warning lights. In the quadrant below the binnacle there are three levers?on the left, the emergency fuel shut-off, wire locked for the discouragement of inappropriate use.
Then there's the governor lever - apparently you can use this to tweak the engine revs downward by about 1,000 in the cruise for economy, but it makes little difference and there's a plastic plug to stop it moving. On the right is the power lever, marked 'throttle', no doubt to the fury of purists.
Surprisingly (to me, anyway) the engine was ridiculously easy to start. If you're used to the three-handed split-brain sequence of something like a sixties Allison in a JetRanger, you'll be an instant convert to the French Way.
First, check to see you've got a blade at twelve o'clock. If you haven't, you'll be barbecuing one on the jet pipe, so get out and sort it. Rotor brake off, batt on, CBs in, fuel on, flick the fuel boost on for thirty seconds. Lift the guard and switch the starter to 'on'.
Lights will illuminate as the starter spools up?red when the starter relay is engaged, and orange at 4,000 revs when the flame igniter micropump comes on. Watch the TOT, which is red-lined at 550 degrees; on this day it didn't get much above 450 before falling back, and Warren tells me he's never seen it hit 500.
The engine is self-sustaining at the 12,000rpm idle setting, and a green light tells you you're in business. And that's all there is to it.
The noise level is fairly high, and the highest-pitch turbine whine intrudes through the ANR headsets, although it's never uncomfortable and you can actually make yourself heard without a headset on?I wouldn't recommend it for long, through.
Work the 'throttle' gently up to 23,000 revs, dipping it quite sharply in the early stages in order to encourage the clutch to kick in. Carry on to 28,000rpm, frictions off, throttle to 34,000 revs, by which time rotor rpm should be getting up towards 350rpm. Throttle finally to the gate, and you're ready to roll.
Vibration levels are quite remarkably low. The head is well balanced and there's no appreciable buzz at all from the engine; the binnacle remains rock steady. Lights out, Ts and Ps good, and lift the lever.
CJ suffered a little from a crotchety lever?Warren thinks the friction system may not be fully disengaging and is getting it fixed?but otherwise the controls were sensitive to the point of friskiness.
Only the cyclic is boosted, but tail rotor authority seems marvellous, and the lightest touch was needed on the pedals. Flying out of balance, as one does when having one's picture taken from another helicopter, was a simple exercise.
With two POB and an almost-full tank we hovered at 13 degrees on the collective and climbed out at 14 degrees. Best rate of climb is 50 knots, so I used 55 for climbing and descending. She may weigh a tonne, but CJ handles well?not as squirrelly as small piston helicopters but instantly responsive to small control inputs.
In level flight at 13 degrees we settled out at 90 knots, and the lack of vibration is truly impressive. You can put the power to work by climbing zero-speed at 2,000fpm or more, but the over-riding thought is for fuel flow, which must be well north of 200 litres an hour during hard work.
She comes down as fast as she goes up, settling out at around 2,200fpm in autorotation, and with that big heavy rotor head there's all the time in the world to flare off speed and rate of descent for the landing. The rotor speed range is massive?minimum is 280 and maximum 450.
Steep turns were predictable, with little tendency for the pitch to change, but an interesting feature was a vibration that arose during deceleration, particularly at low speeds?the transition to the hover was accompanied from around forty knots to twenty knots by an airframe shake that is all the more surprising, given the lack of vibration in other regimes of flight.
Wind direction seemed immaterial. I've since questioned pilots with experience on type about this, and they say "they all do that, sir".
After landing, the throttle was retarded to 28,000rpm for one minute, then closed all the way with the fuel boost off.
Starter switch goes to the off position at this point. Rotor brake can be applied at 170rpm but we were content to let it settle in its own time?and again, there was no 'padding'.
'On condition' operation
It's 64 years since the Alouette II first flew. Sud Est disappeared into what became Airbus Helicopters, and Turbomeca became Safran, one of the big beasts of the European turbine world?and both owe their success to the foundation laid by the Alouette.
The Alouette II is a turbine with the sort of handling characteristics that make it suitable for a relatively low-time pilot. Predictable and vice-free, it represents an easy step up from a basic trainer.
Moving from the joys of ownership to the despair of paying for stuff, you'd have to say that the break you get on the purchase price could well be compensated for by the thirst of the beast.
But further in its favour, everything is on-condition so it costs nothing to look at it sitting on the ground.
Spares are not hard to come by, I'm told. I'm still going to buy a 109 when my numbers come up, but I could see myself getting an Alouette too, for the sheer hell of it.