Flight test: SIAI-Marchetti S.205-20/R
PUBLISHED: 16:32 06 March 2018 | UPDATED: 16:57 06 March 2018
It might look like a PA-28 but is still offers all the fine handling and performance that you would expect from such a distinguished Italian manufacturer. Words Dave Unwin, photos Keith Wilson
As we fly across The Wash towards the rusty shipwreck, I nudge Fenland Aeroclub’s CFI Steve Brown and boast, “I once dropped a bomb on that!” He’s not impressed.
I’m often asked up at the gliding club if I’ve recently flown anything interesting for Pilot, and when I said “yes, a rather fine SIAI-Marchetti” they all went “Ooh, SF.260−cool”, as one occasionally visits Saltby.
However, while it’s true that the sleek, sexy SF.260 is the first type that comes to mind when you say ‘SIAI-Marchetti’ in fact the Italian company built several succesful GA aircraft in the 1960s and 1970s, including the subject of this month’s flight test, the S.205-20/R.
The S.205 can trace its lineage as far back as 1915, when the original company was founded as SIAI (‘Società Idrovolanti Alta Italia’ - Seaplane Company of Northern Italy). After World War I it gained the name Savoia, when it acquired the Società Anonima Costruzioni Aeronautiche Savoia, the name Marchetti being added when chief designer Alessandro Marchetti joined the company in 1922.
Savoia-Marchetti initially specialised in flying boats and seaplanes, and was much favoured by famed Italian Air Marshal Italo Balbo. It also built bombers, freighters and airliners, and was renamed SIAI-Marchetti in 1943.
In 1964, it began work on a new family of all-metal GA four-seaters, the S.205.
The brainchild of SIAI-Marchetti’s head designer, Alexander Brena, the basic type was designed from the start to encompass several variants, with engine power ranging from 180 to 300hp, and with either a fixed, or retractable tricycle undercarriage as standard.
The idea of course was to provide a wide range of models, from basic trainer to sophisticated tourer. The prototype, (a 180hp, fixed undercarriage S.205-18/F) made its debut at the 1965 Paris Air Show, and SIAI-Marchetti eventually produced around 620 S.205s, spread over six different versions and powered by three different engines.
The type was also marketed in the US as the Waco S.220, powered by a 220hp Franklin air-cooled flat-six. The test aircraft is possibly the most numerous version, a S.205-20/R, and I meet it on a rather blustery July day at Fenland Aeroclub in Lincolnshire.
My initial impressions are that it’s not the prettiest aircraft I’ve ever seen, possibly because as the undercarriage is quite short and the empennage relatively long, it doesn’t look quite right.
However, although it may look like a bit of an ‘ugly duckling’ on the ground, I soon learn that it transforms into a graceful swan in flight.
During the preflight I’m struck by the high build quality. Very well made and in excellent condition, it’s hard to believe this aeroplane is fifty years old. Somewhat surprisingly (bearing in mind the importance of drag reduction) the nose is distinctly blunt.
Power is provided by a four-cylinder air-cooled Lycoming IO-360-A1A, which turns a Hartzell two-blade metal, constant-speed propeller. Access to the engine is excellent, as the cowling hinges open on both sides.
There’s a landing light mounted in the front of the cowling, below the prop.
The fuel (a useful 210 litres) is carried in the wings. However, unlike most aircraft in this class, Steve claims it is possible to put an adult on each of the four seats, fill both the tanks and the baggage bay, and remain below the 1,300kg maximum all-up weight.
As very few four-seat aircraft can carry four adults and full fuel, let alone any baggage, I am slightly sceptical of this, but a quick calculation reveals that this is indeed the case. A further calculation confirms an equally impressive still-air range of around 740 nautical miles, making it an eminently practical tourer.
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The rugged-looking undercarriage is electrically actuated, the steerable nosewheel retracting backwards into the fuselage and the mainwheels inwards into the wings, giving a relatively short wheelbase but wide track.
When retracted, the nosewheel remains completely uncovered, as do the mainwheels, although small doors cover the legs.
The cantilever wings use an early laminar flow aerofoil, the NACA 63 series, and feature about five degrees of dihedral and one degree of washout between the root and the tip. Large honeycomb panels are used in the wing’s construction, providing strength and rigidity without too much weight.
The big slotted flaps are particularly interesting, as they are built in two sections. Mechanically actuated, they offer four positions: 0, 15°, 30° and 43°.
Aft of the cockpit a dorsal fillet joins with the mildly swept fin, which carries a relatively narrow chord rudder.
The two-piece elevator is mass-balanced and carried by the cantilever tailplane, there’s a large cable-operated trim tab in the port elevator half and ground-adjustable trim tabs on the rudder and starboard aileron.
A big baggage bay behind the cockpit is accessed via an equally large door on the starboard side. It can carry almost sixty kilos and is accessible in flight. Access to the cockpit is via a single door on the starboard side.
It is a good step up onto the wide wing root walkway, and I would say the aeroplane could do with a retractable step to help climb up onto the wing. I’d certainly recommend putting the flaps fully down before allowing people to board, otherwise an errant heel could easily damage the flap. The cabin has quite a spacious feel and the large windows let in plenty of light, which adds to the sense of space.
The cockpit’s layout is typical of a mid 1960s GA aircraft, a time when the science of ergonomics wasn’t as well understood as it is today. Consequently, while some aspects are perfectly satisfactory, others are distinctly less so!
Although the pattern of the primary flying instruments does loosely follow the ‘Basic Six’ arrangement the actual installation is more haphazard than usual. The ASI is on the far left of the panel and then there is a proper Turn & Slip and a large modern HSI, with the attitude indicator directly above.
Then there’s an altimeter and VSI, plus a VOR/ILS and ADF. Below the VSI is the tachometer, with a curiously large combined manifold pressure/fuel flow gauge to its right. The centre of the panel is dominated by a Garmin GTN 750, and immediately to its right is a block of six small square gauges that show the fuel quantity in each tank, oil temperature and pressure, amps and cylinder head temperature.
Half-hidden behind the P2’s yoke are the fuel pressure, EGT and suction gauges plus the standby attitude indicator. I thought the latter particularly poorly sited, and wouldn’t like to have to transition on to it in serious IMC.
A real anomaly (at least in my experience) is the location of the undercarriage selector, which is on the far left of the panel. This means that just after takeoff you must change hands on the yoke. There are two lights located next to it, one for undercarriage ‘Up’, one for ‘Down’−and although I’d obviously prefer lights for each wheel, there is also a mechanical undercarriage position indicator.
This is a red rod about 10cm long, with a white knob on top that makes it look a bit like a knitting needle, and is located on the floor, at the base of the centre console. It is operated by the nose leg and goes up and down vertically, which is why you can’t see it in the accompanying pictures (with the wheels down the white knob sits on the carpet).
If you’ve selected the undercarriage down but the red rod shows it is still up, the emergency extension system is operated by a red crank handle next to the P1’s left knee.
A sub-panel below the instrument panel carries the parking brake, a row of rugged-looking tumbler switches, starter and magnetos and alternate air in front of the P1. The circuit breakers are arranged in front of P2.
In the centre are plungers for the throttle, propeller and mixture, prop and mixture being of the Vernier type. There’s a big ‘Johnson Bar’ between the seats for the flaps, sharing this location with the fuel selector, elevator trim wheel and trim indicator.
These last two items look like they’ve been borrowed from a boat. Like the rest of the aircraft, the non-adjustable rudder pedals are big, beefy and built to last. The tops pivot to operate the hydraulic disc brakes, but only on the P1’s side. I’ve seen better designed cockpits, but I’ve also definitely seen worse! As I intimated earlier, it’s pretty well par for the course for a machine of this class and vintage.
The seats adjust and are very comfortable, but unsurprisingly are only fitted with a three-point inertia reel harness. On the plus side there’s a large, perfectly sited DV panel and excellent Rosen sun visors.
There’s no primer, so having used the electric fuel pump to pressurise the fuel line you simply close the mixture, engage the starter and reset the mixture to ‘rich’ as soon as it fires. Slightly surprisingly, cowl flaps aren’t fitted.
Excellent ground handling
Taxying out reveals the 205 to have excellent ground-handling characteristics. The nosewheel steers through the rudder pedals and is positive without being twitchy, the disc brakes are powerful but not ‘grabby’ and the field of view is good.
While changing fuel tanks prior to the run-up I realise that, unlike modern fuel selectors, there is no detent to stop you inadvertently selecting ‘Off’−the 205 is from an era when pilots were expected not to make such basic mistakes.
Pre-takeoff checks complete, I line up the with the centreline of Fenland’s 600 metre Runway 18 and ease open the throttle. I’m expecting to need a fair bit of right rudder at the start of the takeoff roll, and am surprised at how little is required.
As mentioned earlier, the wing uses an early laminar flow section, and during the preflight briefing Steve had emphasised that I must not pull the aircraft off the ground but simply raise the nose at sixty knots, then let it fly when it’s ready.
The acceleration is excellent, although with just Steve and me−and only half fuel−on board, we are about 270kg below MAUW. As the needle of the ASI sweeps rapidly past sixty, I ease back on the yoke to lift the nosewheel off the ground, the mainwheels soon follow and we’re airborne after a ground roll of about 300 metres.
A quick dab of the toe brakes before swapping hands on the yoke and selecting undercarriage ‘up’, then change hands again, retract the flaps, just nudge the trimmer (which is very nicely geared) and set off in pursuit of Fenland’s C172, cameraship for the day, with the VSI indicating a strong 1,000fpm at 75kt.
Almost immediately the overall ‘feel’ of the aircraft produces a very favourable impression. The primary controls are powerful, precise, and also agreeably light, well balanced and nicely harmonised, with low breakout force and minimal ‘stiction’.
The field of view is excellent as the wraparound windscreen is large and curves upwards towards the roof, while the windscreen’s centrepost is not obtrusive. As we cross over the coast and go ‘feet wet’ the Cessna’s window opens and cameraman Keith beckons me into close formation.
The ability to hold formation, cross-controlled and within a wingspan, was probably not high on designer Brena’s wish list, but in fact the 205 copes easily and Keith soon gets his pictures.
The handling really is very good indeed, and excellent for an aircraft designed as a tourer. As we move into close formation I urge Steve to “give Keith your brightest smile−we might make the cover”. “I don’t do smiles” he retorts, “just various levels of glumness.”
With all the photos in the can, I break downwards and away from the 172 in a long sweeping curve and we race back across The Wash.
I point out to Steve the semi-submerged wreck of one of the rusting hulks that the RAF use for target practice, and casually mention that the last time I saw it I was looking through the gunsight of a Jaguar T.4. He’s not impressed, and I return to the evaluation programme.
Although it handles like a sports plane the 205 was designed as a tourer, so the first thing to do is have a look at the cruise performance. Steve recommends a power setting of 24/24 (24 inches of manifold pressure with the prop set for 2,400rpm), and the needle of the ASI soon settles on 135kt, at 6,000ft giving a true air speed of 147kt.
This is achieved with a fuel burn of around 36 litres per hour, which I think is pretty good for a fifty-year old four-seater. Adjusting throttle and prop to a more economical 21/21 still gives 125kt TAS at 28 litres per hour, while pulling the power right back to a thrifty 20/20 drops the fuel flow down to 24, the TAS still up at 120kt.
These are good numbers−but then, the 205 was designed to be an efficient tourer and is in its element in the cruise. The ‘ride quality’ is also very good−not quite like a light twin’s but not far off.
Moving on to a look at stability reveals it to be strongly positive longitudinally, neutral laterally and very positive directionally, hands off. I think the 205 wouldn’t be too onerous to fly on instruments, although the distinctly forward C of G today is helping us.
The low-speed handling and stall characteristics will prove interesting, but first we have to slow down. One of the problems with handling aerodynamically clean, high-speed aircraft powered by air-cooled engines is how to slow down and/or come down quickly, without shock-cooling the engine.
Some aircraft (such as the Cessna TTx, see Pilot, October 2017) manage this perennial problem with wing-mounted speedbrakes, while for one of the 205’s contemporaries, the Bonanza, Beech’s engineers came up with the very elegant solution of designing the undercarriage with a very high limiting speed of 140kt (increased to 154 on later models).
Both arrangements allow the pilot to descend at a reasonable rate while keeping some power on and can be very useful, particularly when flying into busy airfields or when given a ‘slam-dunk’ clearance. As the 205 does not have cowl flaps and the undercarriage and flap limiting speeds are both relatively low (95kt and 89kt respectively) you need to plan ahead.
With the flaps and undercarriage up it stalls around 55 knots, and this drops to 48-49 with flap 30. The pre-stall buffet is quite subtle, but the actual stall is very benign, with no tendency to drop a wing.
In fact, if the aircraft is slowed at 1kt/sec it never truly stalls, but just sort of ‘mushes’ downwards with a high sink rate.
Taking gusty winds in its stride
Back at Fenland, the fine handling continues to impress. Changes in pitch trim when lowering the undercarriage and extending the flaps are negligible and easily trimmed out, while the excellent field of view is−as always−much appreciated.
The wind has picked up since we left and is now really quite strong and gusty, but the 205 takes it all in its stride. Interestingly, although it really is a fine handling machine and is eminently controllable the 205 also possesses excellent stability, and is extremely speed-stable.
Steve recommends seventy knots on final, bleeding back to a ‘last-look’ speed of sixty over the fence, and I have no difficulty maintaining the briefed speeds, despite the turbulent conditions. All the way down final it feels very solid.
For the first landing I use the recommended setting of flap 30 and this works perfectly well, so for the second approach I use full flap. You’d think that with those big flaps dangling down at 43° the aeroplane would really bleed energy in the flare, and I’m ready to catch a high sink rate with a suggestion of power.
However, much to my surprise as it enters ground effect it starts to float, and seems quite reluctant to sit down. I can only surmise that with full flap the air gets trapped under the wing and creates a cushion, as we float further and land longer. Anyway, flap 30 is clearly the way to go.
While debriefing over a coffee in Fenland’s comfortable clubhouse it was obvious that both Steve and and cameraship pilot Paul Brian are enamoured with the 205 and I can see why−it’s a lovely machine, with fine handling and excellent performance.
The most obvious benchmark, both in the 1960s and today, would be Piper’s popular Cherokee Arrow, which is also an all-metal low-wing retractable four-seater powered by a 200hp IO-360.
The aircraft share similar dimensions and masses (the MAUWs are within three kilos of each other), although the S.205 has a slightly greater useful load. The Arrow is marginally faster and has a greater Vne, but the S.205 has a better rate of climb and slower stall speed.
An assessment of the handling qualities can typically be divided into quantitative and qualitative, but in both respects I’d have to give the honours to the Italian. If you’ve ever jumped straight from a Chevrolet into an Alfa Romeo you’ll know what I mean.
Unlike many of its contemporaries, the S.205 is also quite comfortable on grass, and Steve has flown it into and out of the farm strip where my Jodel D.9 Buzz lives!
And here’s an additional bonus for everyone else: unlike most of the aircraft I test for Pilot this S.205-20/R is available for rent, so if you want to sample this very rare Italian thoroughbred give the very friendly Fenland Aeroclub a call.