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31

Samstag, 24. November 2012, 13:32

Pilot Report der G280


Zitat

Belt into the left seat of G280, as we did recently, and it is immediately clear that the Plane-View280 flight deck puts this aircraft on par with the best of Gulfstream's large-cabin aircraft. Brian Dickerson, the company's senior production test pilot, was in the right seat and Bob Wilson, midsize Gulfstream aircraft experimental test pilot, rode along as safety pilot.
Dickerson explained that G280 is the only aircraft in this class to have both full-authority auto throttles and an auto-braking system. It is also the only super midsize aircraft in current production to offer an optional head-up display and an enhanced vision system, although these were not installed on the demonstrator.

Dickerson and Wilson prepped the aircraft and they had the APU running when we arrived at Gulfstream's ramp at its Dallas-Love Field facility (elev. 487 ft.). Outside, the temperature was 33C/91F; inside the aircraft it was 70F.

Pre-start checks were straightforward, using the standby multifunction controller to run through stall warning, TCAS and TAWS tests, plus setting the landing field elevation. The FMS performance database was not yet certified, so Wilson computed takeoff data for a 32,000-lb. takeoff weight and flaps 20 deg. He calculated 106 KIAS for V1 takeoff decision speed, 112 KIAS for rotation and 124 KIAS for the V2 OEI (one-engine-inoperative) takeoff safety speed. En route climb speed was 171 KIAS. Using those speeds and opting for a “bleeds off” takeoff, we computed takeoff field distance at 3,725 ft.
Rolling out of the chocks, we found the nosewheel steering and new brake-by-wire system to be smooth and precise.
Once cleared for takeoff on Runway 13R, we advanced the throttles midway and engaged the auto-throttle system. Rpm advanced to 90.6% N1, providing just under 7,400 lb. of thrust on each engine. With a weight-to-thrust ratio of 2.16:1, acceleration was spirited.
Rotation force was moderate and roll force was well harmonized with pitch force. The ailerons and elevator have virtually no perceptible on-center stiction, making the aircraft quite enjoyable to hand fly. In addition, thrust changes cause very little pitch change. Some pilots may not want to relinquish control to the autopilot, but the auto-throttle system is so smooth and precise that there is little reason not to use it.
After takeoff, the pneumatic system automatically switched from APU bleed air to engine bleed air. At that point, we secured the APU.
Following a 250 KIAS/Mach 0.75 speed schedule, the aircraft climbed westward from Dallas-Love to Flight Level (FL) 450 in 21 min., including a 3-min. ATC delay. That is impressive as the outside air temperatures (OAT) were mostly ISA (international standard atmosphere)+15-17C until we climbed above FL300. At FL450, though, OAT cooled off to ISA-5C. Fuel burn for the climb was about 1,000 lb.

We checked cruise performance at Mach 0.80 normal cruise and Mach 0.84 high-speed cruise at FL450 at ISA-5-6C. At a weight of 30,800 lb., fuel burn was 1,510 lb. per hr. (pph) at normal cruise and 1,810 pph at HSC. The flight manual indicates the aircraft's long-range cruise speed at this weight is Mach 0.79 and fuel flow should be about 1,400 pph. At Mach 0.84, it predicts 1,778 pph at that weight and OAT.
The aircraft was buffet-free up to a 40-deg. angle of bank, corresponding to 1.3g. At maximum takeoff weight, the aircraft has 1.2g of buffet margin from Mach 0.75-0.80 at FL450. Buffet margin drops sharply above normal cruise speed.
We descended to 16,000 ft. for airwork southeast of Abilene, Texas, using idle thrust and the variable position speed brakes for drag. The air brakes produce very mild pitch-up when fully extended and just slight airframe rumble that is unlikely to disturb passengers.

When level at low altitude, we flew a couple of steep turns. It is easy to maintain altitude using the primary flight display's flight path marker and airspeed trend vector. Pitch force is moderately heavy, thereby preventing over control. Roll response, with the help of the fly-by-wire roll spoilers, is crisp, but roll effort is moderate, again preventing over control.

Dickerson next demonstrated the low-speed protection system. If the aircraft is slowed to 72% of the angle of attack (AOA) at which the stall warning stick pusher fires, the auto-throttle system engages and power is advanced to prevent the stall. Up to maximum available thrust, the auto-throttle system will not allow angle of attack to exceed 78% of stick-pusher AOA.
We then flew clean, flaps-20 approach and landing configuration stall approaches to stickpusher at weights of 30,150-30,250 lb. For the three configurations, stall warning stickshaker then stall prevention stickpusher, respectively, were triggered at 139 KIAS and 131 KIAS; 113 KIAS and 106 KIAS; and 107 KIAS and 101 KIAS. Aircraft behavior during each of the maneuvers was very benign.
Next, it was off to Abilene's Runway 35R for pattern work, starting with the instrument landing system approach. Wilson pegged Vref at 128 KIAS for the aircraft's estimated 29,600-lb. landing weight, providing a 23% margin over stall. The auto braking system was set to medium deceleration for demonstration purposes.
We flew the approach at Vref+5 until crossing the fence. The relatively large wing and absence of leading edge/Kreuger flaps provide considerably more ground effect cushioning than in the G200. We floated down the runway for a few hundred extra feet before touching down. The auto-braking action was very smooth and progressive, and the aircraft slowed to moderate taxi speed in about 2,500 ft.

To sample G280's engine-out takeoff performance, Wilson computed speeds of 101 KIAS for V1, 109 KIAS for rotation and 121 KIAS for V2. Just above 101 KIAS, Dickerson retarded the right throttle to idle, simulating an engine failure. Only light left rudder pressure was needed to control yaw because of the powerful FBW rudder system. But the servo system moved the rudder pedals enough to make it apparent to our feet that the left engine was producing substantially more thrust than the right.
The aircraft was easy to control throughout the simulated OEI approach and landing. We noted that thrust response to throttle movement is very linear and predictable with the HTF7250 turbofans, thus speed was easily controlled. That's a vivid contrast to the throttle response of the G200's PW306As.

After landing, we taxied back to sample the aircraft's auto-braking rejected takeoff feature. During our simulated takeoff roll, Dickerson called “Abort! Abort!” just over 80 KIAS. We snapped the throttles to idle. The ground spoilers fully deployed and the auto braking responded with maximum braking effort. There was the slightest tendency toward triggering the anti-skid system, but the aircraft decelerated smartly to a stop with no loss of directional stability.

Returning to Dallas-Love Field, we easily stopped the aircraft in the first 3,800 ft. of runway.

Quelle des vollständigen textes und des Bildes!

"When my time on Earth is gone, and my activities here are past, I want they bury me upside down, and my critics can kiss my ass."Bob Knight

Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety.."
(Benjamin Franklin)

32

Sonntag, 15. November 2015, 00:04

Forenberg.deVideoVimeo

"When my time on Earth is gone, and my activities here are past, I want they bury me upside down, and my critics can kiss my ass."Bob Knight

Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety.."
(Benjamin Franklin)

33

Donnerstag, 31. März 2016, 23:13

Forenberg.deVideoYouTube

Forenberg.deVideoYouTube

"When my time on Earth is gone, and my activities here are past, I want they bury me upside down, and my critics can kiss my ass."Bob Knight

Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety.."
(Benjamin Franklin)