Robbo Jock
Sorry for the delayed response. I’m on holiday doing some island hopping, and only get into the business center periodically. John Farley gave you a good description of how tilting the nacelles has advantages other than just some of the ‘fun stuff’ you can do with the capability. Being able to control the angle of the fuselage is like having a new added dimension. For instance, standard practice on descent into a confined area is to use a 95 degree nacelle angle setting (5 degrees aft) which provides greatly enhanced visibility at a time when it is most needed. Doing this essentially brings the windshield down lower into your sight picture, and effectively increases the area you can see on approach. Those of us in the offshore industry will be especially appreciative of this ability. Approaching drilling rigs or platforms in a helicopter when the wind is such that the approach path puts the main structures and obstacles out of your sight picture can be very uncomfortable, and leaves little for visually judging your speed and rate of descent (especially at night). Being able to drop the nose 5 degrees while maintaining a normal descent profile makes a tremendous difference when visual references would otherwise be minimal. Another advantage of being able to tilt the nacelles beyond the normal swashplate range is that it allows a much steeper slope landing capability than conventional helicopters can offer. These are just a couple of added-value things helicopter pilots will appreciate when transitioning to powered lift a/c. It takes a little getting used to, but for an experienced tiltrotor pilot, taking advantage of these new capabilities will become second nature.
While sitting in the NASA VMS control room I watched a UH-60 pilot on loan from the Army perform a normal tiltrotor take-off and conversion (the Army still has lots of interest in the V-22, but not enough money for procurement). The room erupted with laughter as we watched the external visual display which shows the aircraft as it would be seen flying in real life (you can see the gear, flaps, nacelles, and flight controls move as well as see the attitude change as it flies over a runway, past the control tower, trees, bridges etc.) During the laughter the comment was made, “there’s another helicopter pilot take-off.” I had no idea what he had done wrong, as it looked perfectly natural to me. It was then explained to the Army Major that he had lowered the nose as he added power for departure. Standard procedure in the tiltrotor is to let the nacelles do the work for you. As the nacelles move forward, the ‘cyclic’ stick is used to simply hold the fuselage level, producing a smoother and more comfortable take-off for passengers than can be accomplished in a helicopter (or by an airliner for that matter!).
As for your concern over the additional 5 degrees contributing to an early entry into settling with power/asymmetrical settling, I would imagine that there would be at least some effect on the earlier development of the vortex ring state. By changing the disk angle by 5 degrees you are changing the disk plane relative-wind by that amount, and the blade resultant relative-wind by a lesser amount. I couldn’t quantify the effect (I’ll leave that to the aerodynamicists), but according to the pilots who have been flying tiltrotors for many years, getting into the phenomenon takes extreme conditions. I was taken through what I considered some pretty ‘wild’ maneuvers that are routinely done by test pilots, and we did not begin to encounter any problems. Those of us in the civilian world are going to be operating in a much more docile environment and a more restrictive envelope than our counterparts in the military. However, we are all very interested and will all benefit from the information that will be forthcoming from the wind tunnel, simulator and flight tests to further explore and define the conditions that allow an a/c to enter the state.
Regarding employment, we are not in the hiring mode yet, but we are collecting applications for pilot and engineer (mechanic) candidates now. If you would like to you can send your resume/CV to the address below, and I would recommend periodic updates if your experience level is low. BAAC has recently announced a program delay of 8 months (first flight is now scheduled for August next year) as the result of changing the manufacturer of the 609’s composite fuselage. Initial deliveries will probably be around the 1st quarter of 2003, so you have time to build your flight time!! Good luck to you, it’s definitely a worthwhile pursuit.
Send to:
Aerogulf Services Co. (LLC)
Attn: R.M. Denehy
Dubai International Airport
PO Box 10566, Dubai
United Arab Emirates
[This message has been edited by PTI UAE (edited 15 June 2000).]