Frequently asked questions for your aircraft, or general information can
be found here.
Frequently asked questions for your aircraft, or general information can
be found here.
Q) Why do I need to readjust the Elevator Trim Tab during the installation of the new Swept Blade Turbofan Propeller System on my King Air 200?
A) The elevator trim-tab travel is increased to increase the nose-up trim capability on final approach with landing flaps, gear-down, and full-forward CG at idle thrust, and with Max propeller RPM selected.
The cause is the greater disking effect of the Swept-Blade Propellers' increased diameter.
To compensate, the down travel of the elevator trim tab is extended by 2 degrees.
A similar situation exists on the King Air 300 and 350 with their larger diameter propellers, where the same extended trim is incorporated at the factory.
Q) What is the Magicam?
A) Raisbeck Engineering developed the Magicam to allow installation of the Hartzell/Raisbeck Quiet Turbofan Propeller System on aircraft that are not equipped with an autofeather system. The Magicam removes the need for autofeather by automatically increasing the low pitch stop as throttle position is advanced. This is accomplished by altering the cam shape to induce a forward movement of the beta mechanism upon initial movement of the cockpit throttle. The resultant coarsening movement of the propeller low pitch stop reduces the wind-milling drag on the propeller. This lowers the Air Minimum Control Speed to the currently certified value as long as the throttle of the affected engine remains forward. All other operational characteristics of the Magicam are identical to the Pratt & Whitney cam.
Q) Where are the prop sync pickups on the new C90B/C90GT prop installs mounted?
A) On all new kits for C90B/C90GT models, the spinner bulkheads are pre-drilled at Hartzell for the prop sync pickups. During installation, remove the pickups from the old spinner bulkhead and install them on the new bulkhead. The only difference is the addition of 2 holes on each Raisbeck Prop; the pickups need to be mounted 25 degrees off from each other from one side to the other (5 deg on left engine and 20 deg on right engine). This change helps to reduce the propeller noise.
Q) During Autofeather test procedure, both autofeather lights are flashing. Is this the correct operation?
Yes. For an explanation see the following which is an excerpt from RAC King Air Communiqué 2001-04. "We receive numerous calls regarding the flashing of both autofeather lights during the Autofeather Test procedure. To better understand why the lights flash, we should review the system operation. The autofeather system consists of two pressure switches on each engine, a switch on each power lever, an arm/test switch on the pilot's subpanel, and two annunciator lights. The pressure switches react to oil pressure that is relative to the amount of torque being produced in the reduction gearbox. It is termed “torquemeter oil pressure” and is the same oil pressure that is used for the torque indicating system. The switches are classified as high pressure and low pressure. The exact values vary among the different King Air models. When the autofeather switch is placed in the arm position and both power levers are advanced to approximately 90% N1, the power lever switches are actuated. Both autofeather lights will be illuminated, indicating both sides are armed. Power to operate the timing relays and illuminate the lights is routed through the opposite side high pressure switches. That is, the right high pressure switch activates the left side and the left high pressure switch activates the right side. The low pressure switches are in the ground path for their respective side arming relays and autofeather dump valves. High pressure keeps the ground circuit open. If, for example, the right engine fails, the torque will rapidly diminish. As the torquemeter oil pressure decreases below the value of the high pressure switch on the right side, power will be taken from the left autofeather arming relay to prevent any inadvertent conditions. The left annunciator light will extinguish. The left high pressure switch will still be applying power to the right side. As the right torque drops below the low-pressure switch value, it closes and completes the ground path to the arming relay and the dump valve. The dump valve will open and all oil pressure to the propeller will be relieved to the reduction gearbox and the propeller will feather. This entire sequence happens in an instant."The autofeather switch also provides for a test function. Due to the relationship of the power lever switches to the system, it is not possible to test the system in the ARM position, nor would it be practical. When the switch is placed in the test position, the power lever switches are bypassed. Techniques and values vary slightly between the models but, basically, with both engines running, the switch is held in the test position, and only enough power is applied with the power levers to illuminate the autofeather annunciators. Using the right engine as an example, the right power lever is slowly pulled back and as the torque drops below the high pressure switch value, the left annunciator extinguishes. The right power lever will continue to be retarded until the low pressure switch closes. At that point, the right autofeather annunciator will flash and the right propeller will attempt to feather. Keep in mind that the engine is still running. As the propeller starts to feather, the torque increases. When it gets high enough, it opens the low pressure switch and the dump valve closes. As the propeller refills with oil, the blade angle is reduced and the torque drops again. The propeller will cycle as the low pressure switch opens and closes the dump valve. The right autofeather light will flash in sequence because the ground to the arming is also cycling with the low pressure switch. Occasionally, staying with this example, you will experience the left autofeather light flash while the right side is cycling. This occurs particularly on aircraft with 4 bladed propellers. The 4 bladed installation requires a higher prop rpm and a lower N1 speed than the 3 bladed installation. Since the right propeller is turning faster, the torque surge is high enough, when it tries to feather, to momentarily re-arm the left side. This will cause the light to flash. This condition is absolutely normal. Bringing the power lever all the way back to the low idle position during the test usually allows the opposite light to stop flashing. There are several factors that can affect the torque. Engine speed, prop pitch setting and cold weather are just a few. The condition is less prevalent in the 3 bladed installation, but it can still occur. Sometimes it can be attributed to internal friction in which propeller lubrication can eliminate".
Q) How critical are the Minimum Prop RPM requirements imposed by Hartzell on Raisbeck Turbofan Propellers?
A) Since the release of Hartzell Service Letter HC-SL-61-254, I have received several calls from Operators wanting to know how critical it is to operate the aircraft within the parameters outlined in the Service Letter. The Service Letter lists the following warning: STABILIZED GROUND OPERATION WITHIN THE PROPELLER RESTRICTED RPM RANGE CAN GENERATE HIGH PROPELLER STRESSES AND RESULT IN PROPELLER FAILURE, AND LOSS OF CONTROL OF THE AIRCRAFT. In addition to that statement, the Service Letter calls out for overhaul or retirement of the propeller for exceeding the operational limits specified in the Service Letter. The safety and financial implications of not complying with the Service Letter make compliance a necessity. See Hartzell Service Letter HC-SL-61-254 for details.
Q) I have factory Hartzell propellers installed on my aircraft and I would like Raisbeck/Hartzell propellers. Do I have to modify the de-ice/synchrophaser brackets?
A) If your aircraft has the de-ice bracket P/N's 101-960115-1 installed, (see aircraft IPC for S/N effectivity) NO modification of the bracket is required. If your airplane has brackets P/N 50-910584-33, then the brackets need to be modified according to Raisbeck Engineering Inc. Installation Instructions. (When HawkerBeech reverted to installing four-blades at the factory, the de-ice/synchrophaser brackets received a new design.) Adjust the clearance between the synchrophaser and the magnetic pick-up per Hawker Beechcraft King Air Maintenance Manual. Stay close to the low end of the gap tolerance, this will provide you with a more powerful the pick-up.
Q) During propeller rigging, I can't get the ground idle prop RPM set to the desired limits without exceeding the P&W engine parameters. What is the next step?
A) Perhaps your flight idle torques are not set correctly. Once they are set properly, the prop RPM needs to be adjusted per the Raisbeck Engineering Maintenance Manual. Make sure the torque indicating system is reading properly, i.e., calibrate the torque system per Hawker Beechcraft Maintenance Manual. We also recommend using a calibrated handheld RPM meter to verify the propeller or RPM. This is more accurate than the cockpit gauges.
Q) What is the TBO for the Raisbeck/Hartzell four-bladed Quiet Turbo Fan Propeller System?
A) On Raisbeck/Hartzell four-blade propellers, the rule is six years or 4000 hrs.
Q) I had Raisbeck/Hartzell four-bladed Quiet Turbo Fan Propeller System installed on my King Air 200 or B200. I have noticed that the (Vmca) between the 200 and the B200 are different. Why is that?
The reason for the difference in airspeeds is because the straight 200 airspeed indicator is marked for True Calibrated Airspeed (TCAS). Starting with the B200, Hawker Beechraft uses the True Indicated Airspeed (TIAS) for the airspeed indicator. The conversion from TCAS to TIAS is 5 knot decrease at Vmca airspeeds. In the Raisbeck Propeller Installation Manual the Vmca for the 200 is 96 knots and the Vmca for the B200 is 91 knots.
Q) Can I install abrasion tape on the bottom side of the ZR LITE flaps to protect them from unimproved runways?
A) No. Although Learjet SB35/36-27-29 allows for the installation of abrasion tape using kit #2484098-801, it is not advisable for ZR LITE installations. The ZR LITE flaps are made of composite material and installation of the tape would interfere with the lightning strike protection on the flap. In addition, the ZR LITE flaps are constructed with extra layers of material on the bottom to protect against debris impact.
Q) Does the ZR LITE installation change the life limit on the older style Lear 35/36 flaps?
A) No. The ZR LITE installation does not affect the life limit of the older Lear 35/36 flaps. The older style flaps still have a mandatory retirement at 20,000 hours, regardless of whether the ZR LITE kit is installed or not. Determining affectivity is the responsibility of the installer.