|01-02-2003, 05:05 AM
Join Date: Nov 2001
Commercial Tiltrotor Begins Flight Testing
The Bell Agusta BA609 commercial tiltrotor is about to enter flight testing, for certification in 2006. Able to take off and land like a helicopter, but cruise nearly as efficiently as a fixed-wing aircraft, the company envisions the aircraft being used for business aviation, law enforcement, offshore oil transport services, and charter and air taxi services.__________________
The fate of the BA609 has been closely linked with the V-22 Osprey, which had two fatal crashes in 2000 and has certainly dampened the enthusiasm for the BA609 among potential operators, as well as stretching out the development program.
The V-22 has recently resumed flying and is about to undergo make-or-break testing of possible design deficiencies involving when and how the rotorcraft enters "vortext ring state", a condition where the rotorblades stall during a rapid descent. All helicopters can enter this condition, but the dynamics of the interaction of the two sets of rotorblades were more complicated than expected. If the V-22 program is cancelled, I doubt that the BA609 will ever enter service.
As a small aside, a number of my former colleagues at General Electric Aircraft Instruments worked on the VSLED, V-22 Structural Life and Engine Diagnostics program. After the V-22 crashes, the investigators cited the flight data recorder for design flaws and software and wiring problems that caused it to lose many seconds of data right before the crashes, severely hampering the investigation. The VSELD, however, recorded engine vibration, temperature and pressure data from several locations, plus several structural data points right up until the crashes, and data about the aircraft's performance was able to be inferred from the VSELD-collected data. Way to go, guys.
|01-05-2003, 04:46 AM
Join Date: Sep 2001
What is the incentive to do this for regular business aviation and charter flights?__________________
I'm certainly not against innovation, but it seems like there's an incredible price (time, money, risk of human life, etc) for this kind of development that doesn't seem in line with the minimal benefit if you consider that most travel is to areas where runways are readily available, etc.
(You can see Quicktime VR footage of both the inside and outside of the BA609 Tiltrotor here)
|01-05-2003, 10:09 AM
Join Date: Nov 2001
Tiltrotors shine vis a vis helicopters on longer flights of, say, 150 miles or more, where the higher speed and greater efficiency of the tiltrotor in airplane mode (my term, not theirs) results in potentially dramatically shorter flights with less fuel burn. I could imagine tiltrotors operating as life flight helicopters in rural areas, where distances and travel times to and from major hospitals may be large.
As an executive tool, it may in many cases be much quicker to take a tiltrotor from the roof of headquarters directly to a destination within a few hundred miles rather than taking a helicopter to an airport and transferring to a conventional aircraft.
As airport flight activity continues to increase, or hopefully will after we rebound from 9/11, with almost no new runway construction anywhere in the United States in decades, the versatility of VTOL aircraft may be required as a way to relieve airport congestion. VTOL airports have a much smaller footprint than traditional ones, and can be placed in urban areas where a CTOL airport never could. Imagine being able, for a price premium, to able to depart downtown Chicago on a tiltrotor flight to, say, Springfield IL, instead of taking a cab to O'Hare (or at least Midway) and all that.
As to safety, helicopters are, I think, provably less safe than conventional aircraft. Certainly in my own reading of accident reports at the ntsb.gov website http://www.ntsb.gov/ntsb/month.asp it seems that helicopter accidents much more often involve mechanical failure, yet people are willing to endure the risks for the convenience or capability that is otherwise unavailable.
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