Wichita Falls, Texas: Monday, October 11, 1999.

Photos of CarterCopter retracting its landing gear. (photos by: Brad Redding)

Click on all Photos for a Larger Version

V-8 ENGINE INSTALLED IN THE CARTERCOPTER

The V-6 engine in our rotorcraft was badly damaged due to an oil pressure loss (Press Release, August 24). The cause of the oil pressure loss was a broken oil pump drive shaft. This incident occurred during an engine mapping session and the oil pressure data was overlooked.

At the end of August, a decision was reached to replace the GM V-6 engine instead of rebuilding it - as was done several times previously. The decision was based on the following reasons:

1. The V-6 engine was inherently rough running due to the crankshaft producing a non-uniform firing schedule.
2. The non-uniform firing did not run well with a load placed on it when pre-rotating the rotor at low RPM. The uneven firing order of the engine caused the RPM to change significantly between every other power pulse.
3. The V-6 produced insufficient HP to give good jump take-off capabilities without significant modification (i.e. turbo charging).

The Corvette LS1 V-8 engine was chosen to replace the GM V-6. Once the decision was made, all efforts were focused on modifying the rotorcraft to accept the LS1. The following steps were taken:

1. Dry fitted the engine in the rotorcraft to determine spacing required and parts to be redesigned.
2. Engine brackets were modified to hold the drive shaft.
3. Rebuilt the drive shaft.
4. Replaced the drive belt for the rotor with a different size belt.
5. Modified the drive belt pulley.
6. Removed rotor, rotor head, rotor drive and pulley for modifications.
7. Shortened the pre-rotator shaft.
8. Machined new drive belt pulley supports.
9. Designed / fabricated brackets for alternators.
10. Designed / fabricated a new idler belt tensioner system. The new system allows the propeller to act as a flywheel to prevent reduced RPM between engine firing pulses.
11. Removed, modified, and re-installed control cabling system.
12. Installed rotor assembly.
13. Installed LS1 engine.
14. Rewired electrical connections to engine.
15. Fabricated a new exhaust manifold.

OTHER IMPROVEMENTS CONTINUED ON SCHEDULE

Concurrent with the LS1 modifications, the following improvements were made:

1. Designed and assembled dual control system. The main components are in place and require only a few additions to complete the system.
2. Designed and fabricated a cyclic fore & aft and side/side trim using air cylinders.
3. Designed and fabricated a collective lock with a manual and electric override.
4. Designed and fabricated an electrically operated on/off hydraulic control stick damper with adjustable orifices.
5. Redesigned the data collection / prop pitch control system. The computer, which formerly performed both functions, will now perform only the data collection function. A separated computer is being developed to perform the required calculations for prop pitch control and control the prop pitch based on those calculations.
6. Upgraded the data collection system with separate pilot and copilot displays in addition to a central display.

NEXT FLIGHT TESTS ARE TENTATIVELY SCHEDULED

The LS1 installation was completed last Friday on the 8th. The engine was started that same day without any major problems. The next step is to carefully check the entire system in our test pit. This includes running the engine at full HP and the rotor at the maximum RPM attainable until a minimum of 5 hours of run time has been accumulated. Assuming the testing and re-calibrations go smoothly, we plan to fly again towards the end of this month. Hopefully we can fly at Sheppard AFB and use one of their long runways. Due to the numerous improvements made since the last flights on June 3 (Press Release, June 11), the first flights will remain over the runway as a safety precaution. As confidence is reestablished, we will then pursue development of techniques needed for zero-roll takeoffs and landings. Next, we will fly the traffic pattern and slowly increase our airspeed and unload the rotor.