Gulfstream G150 Analysisd16bsf97ryvc45.cloudfront.net/Media/2013/01/g150.pdf · Step aboard Gulfstream’s new G150 and you might find it dif ficult to be - lieve that it’s a direct

38 Business & Commercial Aviation n November 2005

A n a l y s i s

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By Fred George

Step aboard Gulfstream’s new G150and you might find it difficult to be-lieve that it’s a direct descendant of

the super-lean G100, the cruise perform-ance leader in the midsize class. Whileclosely based on the G100 type design, theG150 offers passengers a full foot morecabin width and 2 inches more height thanits predecessor. Like the G100, the G150

can carry four passengers 2,700 nm at long-range cruise or dash more than 2,400 nm athigh-speed cruise with the same payload.But unlike the G100, the G150 has atranscontinental cabin to match its coast-to-coast range.

The G100/Astra family was a frequentfirst-place finisher in midsize performanceand the last-place finisher in sales during its20-year production run. Cabin size was itsdownfall. So, Gulfstream decided to takedrastic action after acquiring the IsraelAircraft Industry (IAI) made jet and

squarely address the model’s shortcomings.As a result, the last G100 aircraft will rolloff the Tel Aviv assembly line in early 2006.The G150, which was “stretched” in width,now boasts 25 percent more cabin volume,making it much more competitive in themidsize class. When the first customers re-ceive their airplanes in third quarter 2006,they’ll find cabin comfort more befitting ofa Gulfstream product.

Some circular cross-section midsize air-craft still boast slightly wider cabins thanthe G150’s. But Gulfstream’s newest model

With its ingenious extra girth, the G100’s successor now boasts a best-in-class

cabin cross-section to complement best-in-class cruise performance as well.

BCA • ISSUE: November 2005PAGE: 38 / Version: #1

has a uniquely shaped fuselage with rela-tively flat sidewalls and an arched top sec-tion. This design offers 2 inches moreheadroom and considerably more shoulderroom for passengers seated in forward- andaft-facing chairs than most tube-shapedcompetitors. The advantage in availablehead and shoulder room is even more ap-parent when one is seated on a side-facingdivan. Few people on the G150’s divan willbe forced to bow their heads as they mightaboard a circular-shaped midsize aircraft.

Other features also contribute to theG150’s improved cabin environment. Thenewest Gulfstream has the G200’s largeroval cabin windows that let in considerablymore ambient light than the G100’s rectan-gular transparencies. Passenger seats havebeen redesigned with armrests that rotate

down from the seat back, rather than pop-ping up from the sides of the seat cushion.The seat cushions now measure 22.5 incheswide, resulting in five inches more availablewidth for the hips. The G150 also has thewidest floor in the midsize class, helping toprevent passengers’ feet from falling downinto the dropped aisle.

Compared with the G100, the G150’sheated aft exterior baggage compartment is13 cubic feet larger, now providing 55 cubicfeet of storage. Forward and aft interiorclosets provide another 25 cubic feet of lug-gage storage. Among the G150’s midsizecompetitors, total luggage and baggagestorage volume is exceeded only by theCitation Sovereign.

With all the G150’s apparent assets, it’sreasonable to ask why the program is nearlya year late. Gulfstream and partner IAIlaunched the G150 program in September2002, with 50 orders and 50 options placedby NetJets. But in spring 2003 the programwas put on a nine-month hold because ofthe record downturn in the business aircraftmarket in the wake of 9/11.

Following the first sign of recovery in late2003, the G150 development program re-sumed full speed ahead. Assembly of thefirst of two flight-test aircraft began in April2004, and the G150 program is now pro-ceeding apace. Static testing is complete, in-cluding a 160-percent overload of the wing.Serial number 201 was rolled out in January2005, and it first flew in May 2005 on a four-hour, 13-minute mission with RonenShapira, IAI’s chief pilot, and Yoram Geva,G150 senior test pilot, at the controls. As ofAug. 31, s.n. 201 had flown 230 hours on 67missions. Serial number 202, the second

flight-test aircraft, made its first flight dur-ing the first week of September. The de-velopment program is on track as measuredby hours flown and test cards completed.

Gulfstream and IAI officials, as a result,are confident they can earn type certifica-tion by first quarter 2006, paving the wayfor initial G150 customer deliveries in thethird quarter. The aircraft’s range and speedtargets are being achieved. Its engines aremeeting required performance, and systemsreliability has been excellent, enabling twoflight-test missions to be completed practi-cally every workday. There’s a “road map”in place to meet weight target goals.

So, when Gulfstream invited B&CA to flythe G150 in late August, we jumped at theopportunity, and on Aug. 31 became thefirst to fly the aircraft outside of companyand government pilots. Although it wasonly its 66th flight, the G150 more than metour expectations.

Structure, Systems andMSG-3 Maintainability

The G150 is being certified as a derivativemodel that will be added to the type cer-tificate of G100/Westwind Astra. To pre-serve the G100’s wing strength margins, theG150’s VMO was reduced from 350 KCASto 330 KCAS and its MMO was pulled backfrom 0.87 Mach to 0.85 Mach. The forwardand aft c.g. limits also were slightly reducedto preserve the G100’s stability and controlcharacteristics.

Like the G100 and G200 — also made byIAI — the G150’s primary airframe is a con-ventional, damage-tolerant, aluminummonocoque structure assembled using tra-ditional construction processes. Similar to

Business & Commercial Aviation n November 2005 39www.AviationNow.com/BCA


The cabin has foldout worktables, remote entertainment system controls and an optional Iridium sat-com phone system with a cordless handset.


A n a l y s i s



Range/Payload Profile

Range (nm)

Gross TakeoffWeight (lb)

Data

Sou

rce:

Gul

fstre

am A

eros

pace

5,000 ftISA+20C

SLISA

0 2,5002,0001,5001,000500 3,00019,000

5,1403,650 20,000

21,000

6,3504,100 22,000

23,000

7,5804,880 24,000

25,000

9,7505,830 26,000

27,000

Takeoff Field Length (ft)

4

5,102

2

2,531

6

7,980

6+35

8,874

Time (hr)

Fuel Burn (lb)

Conditions: NBAA IFR reserves (200-nm alternate), zero wind, ISA, 0.75 Mach cruise

speed, 15,100-lb BOW

Max Payload

1,600-lb Payloa

d

800-lb Payloa

d

Zero Payload

Spec

ific

Rang

e (n

m/l

b)

Speed (KTAS)

Data

Sou

rce:

Gul

fstre

am A

eros

pace

Specific Range

0.30

0.31

0.32

0.29

0.28

0.27

0.26

0.25

0.24

0.33

0.23440 460 480420

Conditions: 21,000-lb cruise weight, zero wind, ISA

FL 450FL 430

FL 370

FL 350 FL 390

FL 410

0.82

Mac

h Cr

uise

0.75

Mac

h Cr

uise

3,000

500

1,000

1,500

2,000

2,500

0

Dist

ance

(nm

)

Time (hr)

Time and Fuel vs. Distance

4 5 6321 70

Data

Sou

rce:

Gul

fstre

am A

eros

pace

High-Speed Cruise

Long-Range Cruise

777 nm2,915 lb

1,691 nm6,152 lb

2,400 nm8,874 lb

740 nm2,531 lb

1,592 nm5,102 lb

2,700 nm8,874 lb

2,451 nm7,980 lb

Conditions: 15,100-lb BOW,tanks-full payload, zero wind, ISA,

NBAA IFR reserves (200 nm)

These graphs are designed to illustrate the performance of the Gulfstream G150 under a variety of range, payload, speed and den-sity altitude conditions. Do not use these data for flight planning purposes because they are gross approximations of actual aircraftperformance.

Time and Fuel vs. Distance — This graph shows the relationship between distance flown, block time and fuel consumption for the G150at high-speed and long-range cruise with full tanks and an 800-pound (four-passenger) payload. High-speed cruise is flown at 0.80 Mach(459 KTAS), and 0.75 Mach (430 KTAS) is used for long-range cruise. Both profiles assume optimum cruise altitude.

Specific Range (Mid-Range Weight, ISA) — This graph shows the relationship between cruise speed and fuel consumption for the G150at representative cruise altitudes for a 21,000-pound aircraft. The data were supplied by Gulfstream Aerospace performance engi-neers. B&CA believes Gulfstream’s performance estimates are conservative, based upon our demonstration flight observations.

Range/Payload Profile — The purpose of this graph is to provide simulations of various trips under a variety of payload and two air-port density altitude conditions, with the goal of flying the longest distance at high-speed cruise. Each of the four payload/rangelines was plotted from multiple data points by Gulfstream’s performance engineers, ending at the maximum range for each payloadcondition. The graph illustrates that the G150 can carry four passengers 2,700 miles and eight passengers 2,400 miles at the 430KTAS long-range cruise speed. The two columns on the left side of the chart illustrate the G150’s FAR Part 25 takeoff field lengthperformance for sea-level standard day and for B&CA’s 5,000-foot elevation, ISA+20°C airport conditions.

Gulfstream G150

the G100, the fuselage is built from cross-sectional frames, longerons and stressedskins, but it’s stretched 16 inches aft of thewing to balance the weight of the wider andheavier fuselage. The stretch also improvespitch and yaw stability and control charac-teristics because the tail is pushed fartheraft, thereby increasing the moment arm.

The G150 shares its first-generation, su-per-critical wing with the G100 and G200aircraft. Aerodynamically, it’s closely relatedto the wing of current-production DassaultFalcon aircraft, but it’s smaller in scale. Thewing has 34 degrees of inboard section lead-ing edge and 25 degrees of outboard lead-ing edge sweep. The wing is quite flexiblefrom root to tip, making for a smoother ridein turbulence. The G150’s long-range cruisesweet spot is 0.75 Mach, but it’s capable ofspeeds up to 0.80 Mach with only a 10-per-cent increase in fuel consumption.

The main parts of the wing are front andrear spars, chord-wise ribs and upper/lowerstressed skins. Each wing also has a rearsubspar that provides the aft attachmentpoint for the main landing gear. The as-sembly is quite flexible, producing a softride in turbulence. But it’s also very strong.The G150’s wing survived the 160-percentultimate overload during static testing be-

cause by that point the static test fixture hadrun out of travel.

Many secondary airframe structures in-cluding the radome, gear, baggage com-partment and access doors, plus winglets,wing leading edges and some flight controlsurfaces are built from fiberglass, Kevlar andcarbon fiber composites.

Gulfstream and IAI wanted to preservethe G100’s cruise performance capabilitiesin the G150 in spite of its considerablylarger fuselage and even though it uses es-sentially the same engines. The G150’sBOW also is 565 pounds higher than thatof the G100. So, drag reduction became anobsession in Savannah and Tel Aviv from



Price as Equipped . . . . . . . . . . .$13,500,000

Characteristics

Seating . . . . . . . . . . . . . . . . . . . . . . . . 2+6/8Wing Loading . . . . . . . . . . . . . . . . . . . . . 69.0Power Loading . . . . . . . . . . . . . . . . . . . . . 2.94Noise (EPNdB) . . . . . . . . . . . . . . . . . . . . . TBD

Dimensions (ft/m)

ExternalSee Three-View

InternalLength . . . . . . . . . . . . . . . . . . . . . 17.7/5.4Height . . . . . . . . . . . . . . . . . . . . . . 5.8/1.8Width (Maximum) . . . . . . . . . . . . . 5.8/1.8

Power

Engines . . . . 2 Honeywell TFE731-40AR-200GOutput (lb) . . . . . . . . . . . . . . . . . . . 4,420 ea.Flat Rating OAT°C . . . . . . . . . . . . . . ISA+27°CTBO (hr) . . . . . . . . . . . . . . . . . . . . . . . . 3,600

Weights (lb/kg)

Max Ramp . . . . . . . . . . . . . . 26,150/11,862Max Takeoff . . . . . . . . . . . . . . 26,000/11,794Max Landing . . . . . . . . . . . . . . 21,700/9,843

Zero Fuel . . . . . . . . . . . . . . . . 17,500/7,938c

BOW . . . . . . . . . . . . . . . . . . . . .15,100/6,849

Max Payload . . . . . . . . . . . . . . . 2,400/1,089

Useful Load . . . . . . . . . . . . . . . 11,050/5,012

Executive Payload . . . . . . . . . . . . . 1,200/544

Max Fuel . . . . . . . . . . . . . . . . . 10,250/4,649

Payload With Max Fuel . . . . . . . . . . . 800/363

Fuel With Max Payload . . . . . . . . 8,650/3,924

Fuel With Executive Payload . . . . 9,850/4,468

Limits

MMO . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.850

FL/VMO . . . . . . . . . . . . . . . . . . . . FL 300/300

PSI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.8

Ceilings (ft/m)

Certificated . . . . . . . . . . . . . . 45,000/13,716

All-Engine Service . . . . . . . . . . . . . . . . . . . TBD

Engine-Out Service . . . . . . . . . . . . . . . . . . TBD

Sea Level Cabin . . . . . . . . . . . 23,000/7,010

Certification

FAR Part 25 . . . . . . . . . . . . . . . . . . . .Pending

All data preliminary

Gulfstream G150

19.4'(5.9 m)

55.6' (16.9 m)

56.8'(17.3 m)

The G150 is intended to carry four passengers with full fuel, so the fare-paying folks shouldn’t want forlegroom in the main cabin.


the launch of the program. Gulfstream andIAI engineers completely redesigned thenose of the aircraft, windshields and wing-to-fuselage fairings. Details learned fromthe G450 development program, such asCFD-designed engine pylon fairings, wereapplied to the G150.

The team also covered control surfacehinges, installed gap seals, fitted the air-craft with flush door openers and boltedon low-drag antennas, among dozens ofsmall improvements. Vortex generatorswere installed in the inside radius junctionof the winglets to the wings to preventhigh-speed flow separation. The G150, asa result, will preserve almost all of the

G100’s range performance, Gulfstream of-ficials predict confidently.

Stan Dixon, G150 program director, ex-plained that improving systems reliabilityand maintainability has been a prime focusfrom program launch. The G150 will be anMSG 3 aircraft, the product of a two-yearrefinement process involving customers,maintenance technicians and designers.Basic scheduled maintenance intervals havebeen extended from 250 hours to 500 hours,essentially transforming the events into an-nual inspections for most operators.

LED position lights replace the incan-descent units. Gulfstream, though, chose toretain incandescent bulbs for the landing

and taxi lights, instead of upgrading to next-generation HID, xenon plasma units. Allexternal light mountings have been modi-fied to improve maintenance access.

Most of the G150’s systems are carriedover from the G100 and a few are borrowedfrom the G200. Some systems are modifiedor upgraded for Gulfstream’s newest model.The G150’s fuel system, for instance, carriesover the G100 design with the exception ofa larger aft fuselage bladder tank and elimi-nation of fuselage-to-wing tank transfervalves. Taking advantage of the 16-inch aftfuselage stretch, the fuselage bladder hasbeen enlarged to hold 5,248 pounds of fuel,almost 400 pounds more than the tank of theG100. There’s no need for a supplementalcenter fuel extender tank in the baggagecompartment to achieve maximum range.

The fuselage fuel tank forms the centerof the 10,250-pound capacity fuel system. Asingle point pressure refueling (SPPR) re-ceptacle, aft of the right wing root, is usedto replenish the fuselage bladder tank.There is no fuel quantity preselect featureon the SPPR panel, but the crew can shutoff pressure refueling with a switch in thecockpit when the desired fuel level isachieved. Alternatively, one can use a noz-zle to refill the fuselage tank through a portmounted high on the right side of the aftfuselage.

Fuel from the fuselage tank flows firstinto main wing tanks and then into the cen-ter wing tank in the belly. The fuel usagesequence essentially is reversed so that mainwing fuel is last to be burned and the c.g.migrates forward during flight. The up-shot? If you load the aircraft so that its zerofuel c.g. is in the middle to forward part ofthe envelope, adding full fuel won’t push itout of the aft c.g. limits.

Jet pumps, using motive flow from the en-gine-driven fuel pumps, supply fuel to theengines and move it to the feeder tanks.Interconnect valves, between the left andright sides of the fuel system, allow the fuellevel to be balanced, if necessary. DC electricboost pumps in the feeders supply fuel forengine start, fuel jettison and defueling. Thefuel system must be completely drained onone side to change a fuel boost pump — nota maintenance-friendly design feature.

Left and right engine-driven DC starter-generators, fitted with long-life brushes andmaintenance-free ceramic bearings, powerthe split-buss electrical system. Standardequipment includes Honeywell’s well-proven RE100 APU, which uses the samestarter-generator as the engines. The APUis installed with an effective hush kit, it’s ap-proved for unattended operation, and it canbe operated up to FL 300. Two nickel cad-mium batteries, mounted below the floorof the aft baggage compartment, supply

A n a l y s i s



Cabin ConsiderationsNo aspect of the G150 is receiving more attention from Gulfstream engineers than thecabin environment. The G150 will arrive at Gulfstream’s Dallas completion center asa green airplane, manufactured by IAI, weighing less than 13,000 pounds. In Dallas,Gulfstream will add the APU, the interior furnishings and exterior paint. The G150 thenwill emerge ready for customer delivery.

Six-, seven- and eight-seat cabin seating configurations are available. The seven-seat layout, featuring four club seats in the aft cabin, an additional forward-facing chairon the right side and a two-place divan on the left up front, currently is the most pop-ular design with customers. Long-life LEDs are used for all interior lights. The cabinhas foldout worktables, remote entertainment system controls and an optional Iridiumsatcom phone system with a cordless handset.

The front of the cabin has a coat and crew storage closet, plus a galley on the rightside. The top of the closet has a 15-inch, swing-out video monitor. The galley featurestwo hot liquid containers, a drip tray with overboard drain, large ice drawer and spacefor beverage containers and miniature bottles. A 115 VAC outlet is provided.

Just aft of the entry door on the left side, there’s a second coat closet. There’s afull-width aft lav at the rear of the cabin with externally serviced toilet, vanity and sink,large wardrobe closet and a second 115 VAC power outlet. An optional belted pottyseat is available.

power for APU and/or engine start. A sep-arate emergency avionics battery is installedoutboard of the aft coat closet inside thecabin. All AC-powered systems have beeneliminated from the G150. However, a 115VAC 60 Hz inverter powers outlets in thecabin for the convenience of passengers.

The primary flight controls, with the ex-ception of the hydraulically poweredailerons, are manually operated. The G150uses the G200’s artificial control feel unit tosimulate aero loads in the roll axis. Theailerons can be manually actuated in theevent of a hydraulic failure. The span of theelevator servo tab has been increased by 50percent and it now has variable gearing.These changes reduce pitch control effortby almost one-half, a welcome change fromthe hefty pitch forces of the G100/Astra. Allthree control axes use electric motors fortrim. An emergency-use-only, high-speedaux horizontal stab trim system providespitch control in the event of an elevator jam.The G150’s left- and right-side aileron con-trols may be split for jammed control pro-tection, and the G200-design gust lock isfitted to it.

The slats and flaps are actuated by DCelectric motors that drive gear boxes, flexshafts and ballscrew actuators. A large por-tion of G100 operators’ complaints wererelated to problems with the slat and flapsystems, so Gulfstream redesigned bothsystems with more robust components andthe G200’s shallower bend geometry inthe flex shafts to increase reliability. Atslow speeds and high angles of attack, theslats automatically deploy to enhance stallcharacteristics.

The G150 is fitted with three-position,hydraulically powered, eight-panel flightand ground spoilers. The panels are sub-stantially stiffer than those of the G100, pre-venting them from floating up at high speedand creating drag when they’re stowed. Theeight-panel design allows each panel to de-ploy to 45 degrees for optimum effective-ness and yet meet the FAA’s requirement forroll controllability with one panel malfunc-tioning. The G100’s four-panel spoilerswere limited to 20 degrees of extension be-cause of the asymmetric deployment con-trollability requirement. When used asflight spoilers, the G150’s inboard half of thepanels first are extended. At full deploy-ment, all eight panels extend, creating veryeffective lift dumping and modest buffet.Automatic rejected takeoff and landingground lift dump modes are also available.

The G100’s rugged landing gear is car-ried over to the G150 with a few changes.The main landing gear are moved inboardslightly to compensate for the additionalfuselage width. The nosegear geometry,doors and steering systems have been

changed. Caster has been reduced to im-prove directional stability on the ground.The nosewheel strut has been made com-patible with conventional tow bars, elimi-nating the need for a special adapter head.There are four nosegear doors instead oftwo, enabling the aft nosegear doors toclose fully when the gear is extended,thereby reducing drag. The G150 gets anew digital nosewheel steering control sys-tem with full steering authority throughthe tiller and three-degree steering au-

thority through the rudder pedals. Brawnfor turning the wheels is supplied by hy-draulic pressure. It’s very smooth and theaddition of rudder pedal steering enhancesdirectional control on both runways andtaxiways. The hydraulically powered wheelbrakes, fitted with long-life steel discs, areactuated by an anti-skid brake control unitin the nose bay, mechanically linked to therudder pedals.

There are two 3,000-psi hydraulic sys-tems. The main system, powered by left



The G150’s PlaneviewThe G150’s Planeview system is hosted by Rockwell Collins’ Pro Line 21 avionicsaboard the G150. But without looking at the labels on the avionics boxes, it would behard to tell the system is manufactured in Cedar Rapids, Iowa. The G150’s displays bearscant resemblance to conventional Pro Line 21 systems. The PFD ADIs, for instance,have edge-to-edge sky/earth horizon references. The aircraft symbols have been madelarger and shaped more like real airplanes. TCAS resolution advisory guidance cueshave been added to the ADI. Gulfstream’s signature sidewall-mounted cursor controldevice will be installed on each side of the cockpit. FMS and E-chart databases maybe updated in one’s office or on the road by accessing a link to a secure Web site. Thedatabases then may be downloaded to USB-compatible memory sticks that plug intothe aircraft’s avionics system.

Standard equipment includes four 10-by-12-inch portrait configuration displays withEICAS, dual FMS-6100s with GPS sensors, dual AHRS and a full suite of Pro Line 21radios. The basic package also includes a TWR-850 Doppler weather radar, CollinsTCAS 4000 and Honeywell E-GPWS, plus dual Mode S transponders, ADF radio and aradio altimeter, along with HF transceiver with SELCAL, cockpit voice recorder andThales solid-state integrated electronic standby instrument.

Optional equipment includes dual Honeywell Laseref V units, second ADF and HF ra-dios and single or dual Collins integrated flight information system boxes with E-charts,plus AFIS, L-3 Stormscope and a flight data recorder.

Notably, all standard and optional equipment has been tested for functionality andcompatibility aboard an “iron bird” lab mock-up at Rockwell Collins’ facility in CedarRapids. In addition, the G150 is being electrically, structurally and electronically pro-visioned for other popular options, such as an Iridium satcom phone system.


and right engine-driven pumps, suppliesone set of aileron power control units(PCUs), landing gear actuators, wheelbrakes, nosewheel steering and spoilers.The aux system, powered by a DC electri-cal pump, supplies the emergency and park-ing brakes, thrust reversers and a second setof aileron PCUs. Hydraulic fluid cooling isaccomplished by routing the aileron PCUlines through the wing fuel tanks. Both sys-tems are filled with Skydrol phosphate es-ter fluid. In the event both hydraulicsystems fail, the landing gear can be ex-tended with emergency pneumatics, theailerons revert to manual control, and thewheel brakes may be actuated through therudder pedals using residual accumulatorpressure.

The G100’s ice protection system is usedaboard the G150, but low-profile Goodrichsilver Estane pneumatic boots, instead ofblack rubber boots, are fitted to the wingand horizontal stab leading edges. TheG150’s four glass-faced windshield panes areelectrically anti-iced, with bleed air heatingavailable as a backup on the front panels. Arain-repellent coating eliminates the needfor the G100’s windshield wipers. Theprobes are electrically heated and engine na-celle inlets are heated by bleed air for iceprotection.

Engine bleed air, routed through a pre-cooler in the aft equipment bay, also is usedfor cabin pressurization, heating and air-conditioning. A set-and-forget digital pres-surization controller, borrowed from the

G200, modulates cabin altitude. The RE100APU provides bleed air for ground heatingand air-conditioning prior to engine start.Its bleed air output also is routed via thepre-cooler for better air-conditioner per-formance. Cabin air-conditioning is pro-vided by a three-wheel air cycle machine,using higher pressure for increased coolingcapacity. The G450’s temperature controlleris fitted to the G150, but it’s a single-zonesystem with partial temperature control inthe cabin.

Dried bleed air also is tapped off the hy-draulic accumulators to inflate one of twocabin door seals. The change prevents po-tentially damaging moisture intrusion andfreezing inside the door seal.

A 77-cubic-foot oxygen bottle, mountedin the nose below the avionics bay, is stan-dard. A 115-cubic-foot bottle, fitting intothe same enclosure, is an option.

Flying ImpressionsFor an aircraft that first flew this past May,s.n. 201 was remarkably mature, even for aderivative. We strapped into the left seat ac-companied by Shapira in the right seat andScott Evans, G150 chief pilot, as safety pi-lot in the jump seat. Danny Meidan, IAI’ssenior flight-test engineer, headed up theteam in the telemetry room. The telemetrycrew would record hundreds of perform-ance parameters during our demonstrationflight and remain in constant radio contact.Meidan became a virtual fourth crewmem-ber in the cockpit, just as he had duringB&CA’s May 1998 IAI Galaxy flight.

Almost immediately, we were impressedwith the G150’s cockpit room, seat comfortand excellent outside visibility through thenew, larger windows. The reshaped noseenables the crew to see ahead at relativelyhigh pitch attitudes. There’s ample head,shoulder, elbow and leg room, remindingus of the G200 cockpit. The right-side for-ward closet, when installed, will provideample nav publication storage for opera-tors who don’t opt for the full electronicflight bag capability. The overhead paneldesign has been changed for improvedfunctionality.

Evans and others have completely re-designed the crew chairs for greater comfortand easier operation. The lap belt buckles,for example, have been moved to the out-board strap so that they don’t slam into thecenter console when the crew exits the cock-pit. The seat cushions, backs and headrestseach are independently adjustable in height.

Our second impression was how intuitivethe Planeview cockpit appeared. Basedupon a Rockwell Collins Pro Line 21 sys-tem using the four largest general aviationdisplays, Planeview provides far more use-ful information than is available in the cock-

A n a l y s i s



The G150 first flew in May 2005 on a four-hour, 13-minute mission with Ronen Shapira, IAI’s chief pilot,and Yoram Geva, G150 senior test pilot, at the controls.

TFE731-40 EnginesGulfstream and IAI chose to retain the G100’s 4,250 pounds-thrust Honeywell TFE731-40R-200G turbofans aboard the G150 to expedite the development program and savethe weight associated with fitting the aircraft with a more powerful engine. For theG150, Honeywell increased the takeoff thrust by 5 percent to 4,420 pounds of thrustand raised the ITT limits by means of a “throttle-push” made possible by a DEEC soft-

ware change. Climb thrust also is in-creased by 6 to 7 percent and cruisethrust is pumped up by 4 percent.However, the takeoff thrust flat ratingdecreases to ISA+10°C from ISA+14°C.The revised engine is rebadged as theTFE731-40AR-200G model.

It’s reasonable to ask why Gulfstreamd idn ’ t op t to f i t the G150 w i thHoneywell’s new TFE731-50 turbofans.

They seemed to be the most logical choice because they produce 4,900 pounds ofthrust for takeoff with a considerably higher flat rating. The -50 engines also will havea 10,000-hour TBO. But they’re also substantially heavier than the -40s, so Gulfstreamelected not to use them.

pits of the G100 and current productionG200 aircraft. The EICAS, for instance,substantially improves engine and systemsstatus awareness compared with the G100’sclocks, dials and warning lights design.

The aircraft was connected to groundpower, so there was no need to fire up theRE100 APU prior to engine start. Shapiraran through the prestart checklists and pro-grammed the twin Rockwell Collins FMS-6100 boxes. We positioned the throttles toidle, initiated the start sequence and let theDEECs handle all the start chores.

Our ramp weight was 21,485 pounds, in-cluding 6,000 pounds of fuel, enough to flyalmost 1,500 nm at long-range cruise andland with NBAA IFR reserves. For theG150, IAI and Gulfstream added the G200-style limited-authority nosewheel steeringthrough the rudder pedals, while retainingthe tiller for tight turns. Rolling out of thechocks, the tiller-controlled nosewheel steer-ing system was quite smooth and precise.The rudder pedal steering allowed us easilyto track the centerlines of the taxiways.Braking action was very smooth and yetpowerful when needed. Shapira extendedthe slats, set the flaps to 20 and manually di-aled in 115 KIAS for V1, 121 KIAS for VRand 128 KIAS for V2. Computed one-en-gine-inoperative en route climb speed was160 KIAS. Ben Gurion International’s ATISreported altimeter 29.92, OAT of 86°F andlight winds out of the south.

Once cleared for departure on Runway26, we held the brakes and pushed thethrottles to the stops. When the enginesstabilized at takeoff thrust, we released thebrakes. Directional control was easy be-cause of the G150’s new pedal-controllednosewheel steering. There was no need toresort to tiller-controlled NWS. Rotationforces at 121 KIAS seemed high and liftoffwas delayed. That’s because we’d not set inenough nose-up trim. Using telemetry,Meidan reported rotation forces averaging48 pounds of pull and a takeoff distanceto 35 feet agl at 3,615 feet. Our takeoffdistance would have been a few hundredfeet shorter if we had set the proper pitchtrim.

Climbing through 400 feet, we turned leftfor noise abatement and reduced thrust toclimb. We retracted the flaps and slats at1,000 feet, noting a mild and gradual pitchup with flap retraction. The G150’s flapmovement between the 12 degrees and re-tracted positions has been slowed to lessenthe resulting pitch change and improve pas-senger comfort. As expected, we raised thenose a few degrees to compensate for flapretraction.

On the way up to FL 410, we found con-trol harmony to be excellent. We checkedshort period stability in pitch and roll axes,

finding it also to be excellent. Outside airtemperatures averaged 15 degrees abovestandard for most of the climb, sapping en-gine performance. Using the recommended250 KIAS/0.70 Mach climb schedule, wereached FL 410 about 27 minutes after take-off and burned 1,100 pounds during theclimb.

Checking max cruise performance at FL410 in ISA+2°C conditions, the aircraft sta-bilized at 464 KTAS about four minutes af-ter level off. Fuel burn was 1,430 pph at aweight of 20,200 pounds, yielding a specificrange better than 0.32 nm/pound. Whoa.No wonder Gulfstream officials are confi-dent about their range predictions. That’sabout 15 percent better fuel mileage thanshown on the accompanying Specific RangeChart in this report.

Next, we checked high-speed buffet mar-gins. In a gradual wind-up turn, the G150’swing didn’t start rumbling until we reached1.65 g’s at FL 410. Then it was time to checklong period pitch stability. We pulled up thenose to slow the aircraft 10 percent belowits 235 KIAS trim speed and let go. Thepitch oscillation cycle was 55 seconds, ac-cording to Meidan’s telemetry data, andwell damped, in large part because of theaircraft’s Mach trim system.

We turned off the yaw damper and gen-tly pulsed the rudder to excite yaw-roll cou-pling (Dutch roll). The period was about3.5 seconds per cycle. Even though the yawdamper is required at these altitudes, theG150 exhibited positive yaw-roll damping,albeit at a relatively forward c.g. of 26.8 per-cent, according to telemetry.

Descending to 15,000 feet for air work atMMO/VMO, the G150 remained well com-posed with no airframe rumble and just in-creased airflow noise in the cockpit.Extending the inboard pairs of flight spoil-

ers caused very mild nose-up pitching butpract ica l ly no a i r f rame buf fe t ing .Extending all the flight spoilers caused amild nose-down pitching moment, modestairframe buffet and very effective liftdumping. Descent rates of 12,000 to 13,000fpm are possible using full spoilers at red-line airspeeds.

Leveling at 15,000 feet, we checked pitchcontrol forces in a wind-up turn. This ma-neuver demonstrated the considerable re-duction in pitch control force associatedwith the G150’s new elevator servo tab sys-tem. It was not difficult to hold backenough pressure to sustain a 2.0- to 2.5-gturn at 270 KIAS.

Full aerodynamic stalls in all configura-tions cause all smiles aboard the G150, atleast if you’re in the cockpit. The automaticslat extension system was not yet calibrated,so Shapira extended the high lift devices



Similar to the G100, the G150’s fuselage is built from cross-sectional frames, longerons and stressedskins, but it’s stretched 16 inches aft of the wing to balance the weight of the wider and heavier fuselage.

Similar to the G100, the fuselage is built from cross-sectional frames, longerons and stressed skins.


manually for the clean stall as the aircraftslowed. At a weight of 19,800 pounds, theaircraft stalled at 111 KIAS. Holding backfully on the yoke causes the aircraft to enterinto a gentle pitch rocking motion with vir-tually no tendency to roll off. Let go, addthrust and stall recovery is initiated almostimmediately. Stalls at slats full and flaps 20(normal takeoff configuration) or 40 (land-ing configuration) are just as docile. Bothstalls occurred at 97 KIAS. Holding full afton the yoke just causes the onset of gentlepitch rocking. As soon as pitch attitude isrelaxed and thrust is applied, the aircraft re-covers very quickly.

We headed to Ben Gurion Internationalfor pattern work and accelerated to nearredline airspeed, setting up for a straight-

in ILS to Runway 12. The G150 has a slip-pery airframe, so it’s best to anticipate theneed to slow well in advance of the ap-proach. However, it also has a relativelyhigh 250-knot slat extension speed, sothere’s little need to use the flight spoilersfor normal approach descents. Extendingthe slats, though, does require an increasein pitch attitude to maintain altitude. Mostof the corresponding nose-down change inpitch attitude, caused by extending the first12 degrees of flaps, is mitigated by theirslow extension speed. Extending the flapsto 20 to 40, which occurs at a greater rate,requires less noticeable pitch change tomaintain altitude.

The G150 is stable on approach and veryeasy to control with pleasant control forces

in all three axes. Shapira bugged our VREFlanding speed at 122 KIAS, based upon us-ing full slats/40 flaps, 1.28 times stall speedand a weight of 19,100 pounds. Throttle re-sponse from the TFE731 engines is excel-lent, proportionate to throttle movementand easy to modulate.

At 50 feet agl, we commenced a very slowthrottle reduction and retarded them to idleat 10 feet during the flare. Although we de-celerated below VREF at that point, we stillhad too much speed for touchdown. Theaircraft floated for quite some time until therubber actually contacted the runway. Thetrailing link landing gear proved quite for-giving as we settled on to the pavement.Full thrust reverse is limited to 50 percentN1 rpm to lessen tail buffeting and improvepassenger comfort. As a result, decelerationwithout the brakes is modest, at best.Directional control was excellent, thanks tothe three degrees of nosewheel steering au-thority that’s available through the rudderpedals.

After we rolled onto the parallel taxiway,Shapira configured the aircraft for takeoffwith slats/flaps 20 and set V speeds at 111KIAS for V1, 118 KIAS for rotation, 125KIAS for V2 and 155 KIAS for VENR, basedupon a 19,000-pound takeoff weight. Thiswould be a simulated one-engine-inopera-tive takeoff. And, yes, this time we set theproper pitch trim for takeoff. We positionedthe aircraft on Runway 26 once again andwere cleared for takeoff. This time, though,Shapira pulled back the right thrust lever toidle just after we reached V1 to simulate anengine failure. Moderate rudder pressurewas all that was needed to maintain direc-tional control even though the G150 has norudder boost or rudder bias system.Admittedly, the left engine was producingonly 3,800 pounds of installed thrust due tothe 90°F OAT. We rotated and increasedrudder pressure to maintain balanced flight.Pitch force at rotation was very pleasant. Weretracted the landing gear with a positiverate of climb and held V2 until reaching 400feet agl.

Leveling off about 1,000 feet above therunway, Ben Gurion Tower cleared us toland on Runway 12. We executed a rightteardrop maneuver to align the aircraft withthe runway centerline. Visibility out theright cockpit side window was excellentfrom the left seat. We configured the air-craft at slats/flaps 40, the recommendedconfiguration for an OEI landing. Thistime, we reduced thrust to idle at 50 feet agland let the aircraft slow down a bit beforestarting the flare. There was much less float,but still plenty of residual speed to cushionthe touchdown.

Using thrust reverse on the left enginehelped to decelerate the aircraft during roll-

A n a l y s i s



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Gulfstream G150 Price Index

Gulfstream G150 Comparison Profile®(Percent Relative to Average)

Tradeoffs are a reality of aircraft design, although engineers attempt to optimize theblend of capabilities, performance and passenger comfort.

B&CA compares the subject aircraft, in this case the Gulfstream G150, to the com-posite characteristics of others in its class, computing the percentage differences forvarious parameters in order to portray the aircraft’s relative strengths and weaknesses.We also include the absolute value of each parameter, along with the relative ranking,for the subject aircraft within the composite group.

This Comparison Profile compares the G150 to a composite group of four midsizelight jets including it and Bombardier Learjet 60, Cessna Citation Sovereign andRaytheon Hawker 800XP. The Comparison Profile shows that the G150’s strengthsare fuel efficiency, cruise speed and maximum range. Compared to other aircraft inclass, though, the G150 requires considerably more runway, also as shown on theComparison Profile. The chart, however, doesn’t tell the whole story. The G150’s flex-ible wing offers a more comfortable ride in rough air than some competitors andGulfstream’s product support is tops in its class.

out. We taxied back to the ramp 1.6 hoursafter takeoff.

Our conclusions? The G150 is as pleas-ant to fly by hand as the best of the large-cabin Gulfstreams, and certainly moredocile in full aerodynamic stalls. The con-trol forces are well harmonized and it’s quitestable throughout the flight envelope. Ithandles so well and so precisely that it’stough to surrender control to the autopilot.But RVSM airspace leaves us no option; au-topilot must be used.

Its ground handling manners are just asrefined, with very smooth nosewheel steer-ing and braking action. Pilots and passen-gers alike should enjoy the ride aboard theG150. This is a midsize airplane that emu-lates the ride of a large-cabin jet.

Price, Value and UtilityGlance at the accompanying ComparisonProfile® and you’ll see how the G150 stacksup against its main competitors, theBombardier Learjet 60, Cessna CitationSovereign and Raytheon Hawker 800XP. Its$13.5 million price is within a percent of theaverage, so it’s not much of a factor. TheG150’s strengths are speed, range and cabincross section. Its apparent tanks-full payloadshortfall relative to the average is deceiving.If you offload fuel and trade it for payload,the G150 can fly the same payload almostthe same distance as the composite average.

Cabin length isn’t one of the G150’sstrong suits. At 17.7 feet, it’s the secondshortest in class. But the G150 is intendedto carry four passengers with full fuel, sothe fare-paying folks shouldn’t want forlegroom in the main cabin.

Runway performance might be theG150’s Achilles’ heel. Departing at MTOWfrom Westchester County Airport’s 6,548-foot Runway 16/34, for example, might bea challenge on a hot summer day. Even

more limiting will be Chicago’s Palwaukeeairport, with only 5,000 feet available on itslongest runway. Popular general aviationairports, such as Santa Ana-Orange County,with a 5,700-foot runway; Burbank, with5,801 feet available on Runway 8/26; andCarlsbad-Palomar, with 4,900 feet of run-way, also will be limiting. Within theGulfstream family, as a comparison, onlythe G200 needs more runway for a 1,000-nm trip, according to B&CA’s May 2005Purchase Planning Handbook. When flyingthe G150 on long-range missions, plan onusing at least 6,000-foot-long runways, as-suming sea-level, standard-day conditions.

Operating out of popular high-elevationgeneral aviation airports will be even morechallenging for the G150. Pilots will haveto take a close look at runway performancewhen departing Aspen, Eagle, Sun Valleyand Telluride, among other mountain land-

ing facilities. Boosting the thrust of theTFE731-40 engines by 5 percent reducedflat rating from ISA+14°C to ISA+10°C.That’s especially noticeable when departinghot-and-high airports.

Such extreme examples aside, the G150will be quite capable of operating from typ-ical 4,000-foot general aviation airport run-ways on missions up to 2.5 hours in length,assuming standard day conditions. Oneveryday missions, passengers will enjoyone of the nicest cabin cross-sections in themidsize class, a far cry from the crampedquarters of the G100. The enlarged externalbaggage compartment, relative to the G100,is a welcome improvement. The standardRE100 APU will provide much improvedair-conditioning performance on theground and electrical power for au-tonomous operations. It’s also very quietcompared with the G100’s optionalGTC36-150 unit.

Pilots will find this aircraft as nice to fly asany of its competitors, especially consider-ing its top-of-class Planeview cockpit.Flight department managers will appreci-ate Gulfstream’s product support and theG150’s MSG-3 maintainability.

Stan Dixon and his team are workinglong hours to build reliability into the G150,so that it will live up to Gulfstream stan-dards for gas-and-go dependability. TheG100 has attained a 99.75-percent dispatchrate, Dixon claims. He wants to better thatnumber for G150 operators.

Overall, the G150 is much more of aGulfstream than the G100. Though a de-rivative of the G100, it’s so much improvedthat it’s hard not to believe the G150 is aclean-sheet design. Look for the G150 tomake its official U.S. debut at the 2006NBAA Convention in Orlando. B&CA



Among the G150’s midsize competitors, total luggage and baggage storage volume is exceeded onlyby the Citation Sovereign.

The G150 is fitted with three-position, hydraulically powered, eight-panel flight and ground spoilers.

Documents

Gulfstream G150 Analysisd16bsf97ryvc45.cloudfront.net/Media/2013/01/g150.pdf · Step aboard Gulfstream’s new G150 and you might find it dif ficult to be - lieve that it’s a direct