Piaggio Avanti II

Piaggio Avanti II

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The Piaggio Avanti II is an extraordinary aircraft, in looks, in the cabin, in efficiency. It’s also extraordinary to fly, as Stan HoDgkins found out for P1

THE Piaggio P180 Avanti has been with us for more than 20 years, but for a multitude of reasons it has not made the impact it should have done. In fact, as the company CEO himself has explained, in many parts of the world it has become one of aviation’s best-kept secrets.

Since introducing the upgraded Avanti II in 2005, Piaggio has been trying to put this right and we were invited to the company’s Genoa factory to sample this fascinating example of Italian ‘engineering with flair’.

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I remember at the time of its original introduction being really impressed by its amazing turboprop performance, but at the same time being somewhat cautious about its revolutionary design. Aviation being as conservative as it is, I thought people might not be ready for this just yet.
Some 30 years ago, Piaggio designers Franco Morelli and Dr Alexandra Mazzoni looked at turboprop design from a completely new perspective, and with a clean sheet of paper. It was definitely not a development of their existing P166 pusher-prop but their experience in that area must have been a factor. They started with the concept of a large, comfortable, quiet cabin with all the noisy machinery placed behind the passengers. Passenger comfort was number one. With equal importance came efficiency, in both aerodynamics and engineering.
The design study quickly established that the passengers must be located in front of the main spar and this was just not possible with a conventional design. A canard configuration was then considered but rejected in favour of a forward ‘wing’ plus a conventional high-mounted horizontal stabiliser and elevator. This gave three lifting surfaces and, as the tail did not now have to produce negative lift as in normal designs, the main wing could be 34 per cent smaller, saving considerable weight and reducing drag.

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Another advantage of this layout is that the forward surface – not a canard as it has no control surfaces – is rigged at an incidence that ensures that it stalls before the main wing producing an automatic nose-down effect. Such a radical departure from convention demanded extensive testing, and 4500 hours of wind-tunnel testing were carried out to prove the design. In addition, 1500 hours of flight testing followed, making the Avanti probably the most tested business aircraft yet built.
The final ingredient of this approach was ultra low drag utilising laminar flow and scrupulous attention to detail. The fuselage shape has a circular cross-section, and is an almost perfect streamlined form, the point of maximum width being the centre of the passenger cabin. There is no drag-producing windscreen ‘step’ and the ultra smooth surface (for non-composite construction) enables laminar flow to be achieved over much of the forward fuselage.

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In addition, due to the pusher configuration’s undisturbed airflow over the main wing, laminar flow is achieved over 50 per cent of wing chord, compared with the maximum of 20 per cent normally achieved on tractor-type propeller aircraft.
With regard to general drag reduction, the trouble the designers went to can easily be seen on the pre-flight walk-round. Excrescences are minimal and the unavoidable ones are faired beautifully or designed to produce minimum drag. This is one clean machine.

TYPICALLY ITALIAN

Twenty years ago, the Avanti looked futuristic – and it still does! Approaching the aircraft from the front one is struck by the beautifully streamlined shark-like fuselage with its small forward wing, sitting on its fighter-type landing gear.
The impossibly thin main wing is positioned where most aircraft have their tail and thrusting forward over the top are the long slim area-ruled engine nacelles terminating in stubby five-blade propellers faired by gorgeous, reflexed, pointed spinners. Sweeping up majestically behind is the graceful fin with an almost delicate swept tail-plane and elevator.
To me it seemed a combination of beauty and functional elegance – typically Italian. My Ducati 250 Desmo had the same qualities! Like the bike, if I owned an Avanti I could spend hours just looking at it. For its capabilities, it is smaller than one would expect, but that is because Piaggio have fitted a quart into a pint pot in the name of efficiency and there is no wasted space or structure in the whole machine.

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The forward plane incorporates a two-position slotted flap and has five degrees of anhedral to keep the wake clear of the engine intakes, main wing and propellers. The forward flaps work in conjunction with flaps on the main wing which are plain inboard of the nacelles and Fowler-type outboard. Flap operation is electrical and automatic sequencing is used to minimise trim changes. Flaps travel from up to the mid or take-off setting in 16 seconds and from mid to full or landing position is a further five seconds.

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Flight controls are entirely manual using cables and pushrods. Pitch control is by a conventional elevator hinged to an all-moving stabiliser which provides electrical trimming. Spring feel is used to provide suitable stick forces throughout the speed and cg range. Differential ailerons are used with a trim tab on the left aileron. The rudder is cable operated in the normal way and has an electrically driven trim tab.
Ice protection is provided by an electrical heating mat in the leading edge of the forward wing and by bleed air through a diffuser duct in the leading edge of the main wing. The propellers are conveniently protected from icing by exhaust gas and the tail assembly requires no de-icing. In addition to the empennage, two ventral (delta) fins are fitted. These fins, as well as increasing stability, also provide a nose-down pitching moment at high angles of attack and help to avoid a potential stall.
The two PT6A-66B turboprops are mounted in titanium cradles atop the main wing in composite nacelles. These cradles are constructed from titanium tubes of different diameter and thickness to achieve the required strength at minimum weight and have the most exquisite welds I have ever seen. It is a shame to cover them up. Each engine produces 850shp and is derated from a flat rating of 1630shp and is provided with a halon fire protection system. Hartzell five-blade, contra-rotating, auto-feathering propellers are fitted.

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Electrical power is provided by two 28 volt, 400 amp DC starter/generators and one 25.2 volt, 38 amp/hr nickel-cadmium battery provides power for starting and reserve power in the case of double generator failure. AC current for the avionics is supplied by two small inverters in the cockpit.
The environmental control system utilises engine bleed air for heating, cooling and pressurisation. The cabin can maintain sea level pressure up to 24,000ft and at the maximum altitude of 41,000ft, the 9psi system gives a cabin altitude of only 6600ft.
Fuel is carried in integral tanks in the wings which extend over 20ft outboard and also in a fuselage tank above the wing spar. It is fed by gravity into left and right collector tanks in the equipment bay immediately behind the pressure bulkhead. From there fuel is pumped to the engines.
The left and right systems are separate except when cross-feeding or when being pressure-refuelled. The refuelling receptacle is on the right side of the fuselage under the wing.
The Dowty-Messier landing gear is of cunning design. The single-wheel main gear folding away into a tiny space in the lower equipment bay below the fuel collector tanks. The nosewheel is a conventional twin-wheel unit incorporating hydraulic steering. Sharing the main wheel bay is the extremely compact hydraulic power pack which provides up to 3000psi supply for gear operation and 1200psi for wheel brakes. The undercarriage can be lowered manually in the case of hydraulic failure and the wheel-brakes also revert to manual operation.

 

FLIGHT TEST

On the walk around, which was straightforward, Piaggio’s Experimental Test Pilot Lorenzo Villi showed me some really neat features on the Avanti, such as the remote indicators showing engine oil contents, and the entrance door. This is split, the top two-thirds opens to the left, but the lower third drops down forming an air stair.

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The aircraft we were to sample belongs to Ferrari, a company that has connections with Piaggio, and was finished in gloss white with a neat Ferrari red cheat line sweeping up the rear edge of the rudder. Discreet prancing horse badges feature on the nose and fin. The finish is super-smooth. It could have been composite until given a closer look.
Inside, the cabin is immaculate in hand-sewn leather corporate fit, with seven seats and a rear toilet. Opposite the door is the plug-type emergency exit hatch and in the rear fuselage is quite a capacious baggage compartment with a maximum load of 350lb. Access to the aircraft battery is also in this compartment.

Because the fuselage was designed around the passengers, the pilots are in the pointed bit. The cockpit could be described as cosy and access did require a little agility and practice. The seats are fixed but to facilitate entry, the seat hinges up and back so you can step over the centre console.

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Once seated there is ample room, but there is nowhere to put your flight bag. I positioned my seat vertically and then adjusted the rudder pedals and all the basic flying controls fell readily to hand. Although the coaming was quite high, the view over the nose was adequate and the view out to the side is unusual, to say the least. Looking forward, the tip of the forward wing is visible while the main wingtip can only just be glimpsed to the rear. It felt very jet-like.

For insurance reasons I was in the right seat, but it seemed to me that everything was fully accessible from either seat. Start-up was standard PT6 and the starter motor automatically tripped out at 50 per cent N1. The engines sounded remote!

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The after-start checks seemed very straightforward and as with all modern aircraft the main activity was pushing buttons on the FMS. I tried to concentrate on the aeroplane and not get too distracted by cockpit technology.

We followed the P166 cameraship out towards the runway using the nosewheel steering. The steering has two modes, taxi or take-off, selected with a button on the yoke. In taxi mode the steering is quite coarse enabling tight turns and is quite sensitive – it just depends what you are used to. The red cut-out button on the yoke also disconnects the autopilot in the air.

CHECKS COMPLETE

Pre-takeoff checks were completed which included selecting mid-flap and we lined up behind the P166, which was also full of bodies with cameras and rolled in turn. With the contra-rotating props there was no need for rudder. Vr was around 100 knots and the aircraft popped straight off the ground. We were quite heavy with a fuel state of 2250lb (max 2800lb) and six passengers. With a wing loading of 67lb/sq ft the Avanti needs 3300ft to clear 50ft. The controls were very positive and this unusual aircraft handled like any other.
Normal climb speed is 160 knots but we joined up with the photo-ship and I discovered that formation flying in the Avanti was delightful – the view out to the side was totally unobstructed by wings or engines, again just like a jet.
I suppose flying formation in an unfamiliar aircraft is a fair way to assess controllability and the Avanti handles well with positive, well-harmonised controls. The photography took quite a while and I certainly had my share of the flying. Cockpit noise was low, just the distant whine of the propellers and the sound of the air conditioning.
Eventually, with the photography completed we parted company and climbed up to FL280. The rate of climb was 2500ft/min at 160kt and the upgraded engines provide undiminished power all the way up.

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On levelling we settled into the cruise at 97.5 per cent torque and reduced propeller rpm to 1800. This reduced the prop noise appreciably and the folks in the back commented on the quiet cabin.
Established in the cruise with a moderate tailwind, I noted a groundspeed of well over 400kt with a 370kt TAS. With the autopilot engaged we had a fuel burn of about 600lb/hr and a comfortable cabin altitude of 2000ft. At its maximum altitude of FL410 maximum range is around 1400nm.
Lorenzo then demonstrated a fast descent to medium level and we levelled at FL150 for a little general handling. If the VMO of 260kt/0.7M is exceeded, audio warnings will sound and if autopilot is selected, the mode will automatically change to speed-hold and the aircraft will pitch up to prevent exceeding the limit.
From the pilot’s point of view, this aircraft is entirely conventional, except that it will not stall. Reducing speed, quite heavy buffet was evident followed by a positive pitch down as the forward surface stalled. We were a bit limited with passengers on board, but the main wing remained unstalled and aileron control was maintained throughout.
In asymmetric flight the Avanti is again conventional and single-engine climb performance is practically identical to the Beech 200. With contra-rotating propellers there is no critical engine. Returning to Genoa, we established on a visual final, selecting the gear down at 180kt, followed by mid-flap at 170.
With full flap selected at 150kt our Vref was 117kt. Touchdown was made with minimum rate of descent and it was on the hot side for a King Air pilot – more like landing a jet. Throttles were reduced to the Beta range and braking was applied. I estimate that we used about 4000ft of runway. Caution must be used when braking as no anti-skid system is fitted.

CONCLUSION

I must admit I enjoyed my Avanti experience. From a pilot’s point of view, it is an exciting aircraft and it has that certain something. As the CEO explained to us, it is a product of Italian passion. That, however, is not the reason why hard-nosed businessmen buy aeroplanes. To them, it is a business tool and the facts and figures have to stand up, and I think that they do.
In a nutshell, the P180 is an aircraft with a wide array of attributes. It has a cabin the size of a Dassault Falcon 50, and combines jet speeds with the more economical fuel burn of a turboprop. This results in miles per gallon figures that beat any rival.
However, it is not an aircraft for short field operation. All aircraft are compromises and you just cannot have it all ways. When compared to the Beech 200, the industry yardstick, it has a bigger cabin, is 100kt faster, goes further and uses less fuel.
Since its original launch over 20 years ago, things have changed big time. Not only has the price of fuel crept higher and higher, there is now a shortage of cash worldwide and everyone is trying to cut costs.
The Avanti’s time may have arrived at last. It’s not cheap at over $7m, but it’s got props, it’s not a flash jet, and it sips fuel like no other. At the same time with its big, quiet cabin and jet speed it delivers the goods. And it does it with passion!

WELCOME ABOARD

WITH the largest and most spacious cabin in its class, perfect pressurisation and exceptional sound deadening, the Avanti II is typically Italian – luxurious and elegant!

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Comparable in cabin space with higher class aircraft, the Piaggio’s cabin cross-section is over 6ft wide and 5ft 9in high. The innovative fuselage shape – wind-tunnel designed for exceptional aerodynamics – combined with the positioning of the engines, gives the cabin its unique roominess and a noise level of just 68 dbA. That’s one of the lowest noise levels ever measured in a turbojet or turboprop business aircraft.
Perfect pressurisation means passengers can experience sea level cabin pressure up to an altitude of 24,000ft making for the most comfortable working environment and allowing the Avanti II to be used in special operations such as air ambulance and air rescue flights.

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The comfort extends as far as the luxurious rear-positioned toilet, which features a seat-belt as it is type-approved for take-off and landing.
To further add to the decadence of this first-class interior, Piaggio offers an options package to turn the aircraft into a true office in the sky. The package offers advanced solutions for onboard connectivity and entertainment including full broadband internet for laptop or smartphone wi-fi; an IFE Inflight Entertainment System with LCD displays and high-end sound system, which includes a moving map of current position and time to destination; a mood lighting system; and high-tech electrochromic window shades which allow the passenger to adjust the level of ambient light entering through the window.

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IN THE COCKPIT

piaggio cockpit
THE three screens of the Rockwell Collins Pro Line 21 EFIS dominate the panel. Each pilot has a primary flight display with its control panel and to the left of centre is the multi-function display. The pilots’ displays show the standard flight instruments in the upper half and the lower half shows navigation information plus other information as selected, such as radar or TAWS.
The MFD has three major display areas, the upper engine information area and two other selectable lower areas. The lower one usually displays navigation information plus TCAS, radar etc, but the two lower areas can also be combined to display approach charts, FMS remote text or system information.
Between the MFD and the co-pilot’s display is the Emergency EFIS, the main annunciator panel and the radio tuning unit.
Centrally placed above the coaming is the flight guidance panel (autopilot controls). Below the main panel and across the cockpit are the grouped controls for the aircraft systems, including the audio panel for each pilot.
The forward part of the centre console contains the master switches for engine, fuel and hydraulic systems, with the parking brake to the left. To the rear of this panel are the throttle levers, and propeller controls. There are no condition levers as they have been integrated with the propeller levers. As the lever is moved forward the fuel cock is opened and then it controls the propeller in the normal way.
To the right is the gated three-position flap selector. Behind the throttles is the FMS and at the very rear of the console are the trim indicators and controls.

PIAGGIO AVANTI II

Max Cruise 390kt
Climb 2950ft/min
Range 1794nm
Ceiling 41,000ft
Takeoff dist 869m
Landing dist 872m
Engines 2 x PWC PT6A-66
Power 2 x 850shp
Mtow 5239kg
Empty 3402kg
Full fuel payload 589kg
Fuel capacity 1271kg
Wingspan 14.03m
Cabin length 4.55m
Cabin height 1.75m
Cabin width 1.85m
Seats 9 pax
Avionics Rockwell Collins Proline 21
Base price $6.6m

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