Subject: NAS2-99090 November monthly report

Date: December 4, 2000

The first part of the month was spent making changes, most of which would improve the cyclic stick force and rotor controllability. Hardware changes made thus far are:

1. All of the control rod end bearings were changed from teflon lined to AL bronze. This reduced the stick force to the right from 8-1/2 lbs. to 6-1/2 lbs. and to the left from 12 lbs. to 6 lbs.
2. Replaced the cyclic stick bellcrank support with a box support instead of an "I" beam support to increase the stiffness of the side/side cyclic travel.
3. Made a new adjustable collective detent with a larger opening and more positive hold.
4. Reduced the blade underslung from 3-5/8 to 1-3/4 inches.
5. Added pot to rudder to monitor rudder travel.
6. Changed out gears in the gearbox and adjusted the pinion so the ring gear's contact point moved down from its edge and nearer to its O.D.
7. Added 4 springs to preload cyclic linkage - eq. 20 lbs. stick force.
8. Added a remote video camera to record blade movement while flying.
9. Added spacer to the bottom of the rudder peddles to keep from operating brakes inadvertently.
10. Tested rotor in pit to determine how much weight could be reduced from the spindle and spar stabilizer bars as a result of reducing the rotor teetering undersling. Tests confirmed the rotor was stable without the spindle stabilizer bar and without 80% of the spar stabilizer bar weight.

On Friday, November 9th, flight testing again resumed. The pilots confirmed very quickly the rotor followed the cyclic input and that the stick forces had been significantly reduced. By Sunday evening, the aircraft performed the first zero roll takeoff. On Monday morning, December 13th, the gearbox failed again despite holding the torque to a minimum and before another zero roll takeoff was made. See the CC web site November 20th press release for more details.

Since the gearbox failure, the following noteworthy items have been completed.

1. Modified cooling air exit for less restriction while aircraft is not moving.
2. Extended the air inlet duct approximately 8 inches.
3. Added 9" extension to both rudders.
4. Added spring to left rudder and to rudder peddle to take slop out of rudder control.
5. Increase travel of collective from 100 to 120
6. Adjusted the collective stick position so it starts at a lower position for more travel.
7. Add another spring to the prerotator clutch idler pulley return so the clutch will release more quickly.
8. Reduce the air quantity in the air over hydraulic prerotator reservoir so the pressure will drop and the clutch will release more quickly.
9. Replaced needle valves in cyclic force trim with flow control valves to reduce the system pressure and air cylinder drag.
10. Reprogrammed the engine computer to idle at 1200 RPM instead of 800 to increase alternator output and keep the battery voltage up.
11. Make throttle grip larger and change throttle cable attachment to make it less sensitive at low throttle settings.
12. Designed new gearbox with 8-1/2" diameter ring gear instead of 6-1/2" diameter. Worked with gear manufacturer to determine optimum size and ratio for given space available. It still has a limited life at the torque required for the maximum overspeed RPM of 425.
13. Finished detailing all the parts (20) to be made for gearbox.
14. Most all parts are finished except for heat-treating and the AL gearbox case. Because of the limited volume available, the housing has a complicated shape requiring a lot of programming and many different cuts.

Work yet to be completed:

1. Finish gearbox
2. Prefinish and paint rudders and air cooling mods.
3. Reinstall rotor, rotor head, prerotator including new gearbox and check out.
4. Check out a number of data collection software changes.
5. Test rotor system and prerotator in the pit.
6. Recalibrate some of the data collection sensors.

Next flight tests are tentatively scheduled for the weekend of December 16th. During these tests we will focus on making a zero roll landing and optimizing the zero roll takeoff and landing techniques. Once the pilots feel comfortable with the takeoffs and landings, we plan to fly a traffic pattern which always keeps the aircraft over a runway. We will then determine the range of collective angles which can be flown at different airspeeds between near minimum to 125 MPH within 8 degrees of flapping and 375 RPM of the rotor. Once these tests have been complete, we plan to take the aircraft up above 10,000 ft to complete the 3rd milestone.