DIY Repair Guidelines – Heavy Lift Drones

Follow the Maintenance Checklist: Regularly inspect the aircraft, batteries, and ground station/controller. Ensure all pre-flight and post-flight checks are completed as outlined in the maintenance checklist.
Use the Appropriate Tools: Use proper tools for minor repairs and adjustments to avoid causing further damage. Ensure all tools are compatible with the drone's components.
Refer to the Manual: Consult the H6 Platform Operators Manual for specific repair instructions. Detailed procedures and guidelines are available for common maintenance tasks and minor repairs.
Contact Support for Complex Repairs: For repairs that are beyond basic maintenance or if you encounter persistent issues, contact Harris Aerial support for professional guidance.

12S Battery Rack Assembly

To assemble the 12S battery rack, it is recommended that a level surface is used to prevent the batteries from becoming misaligned or bowing.

Disassembly - 12S Battery Rack Assembly

Step 1: First, remove the four socket screws located at the top and bottom of each dovetail bracket.
Note: Two screws will have a plastic dowel used as a brace between the dovetail bracket and the battery housing; take note of the orientation that the dovetail bracket is installed for proper reassembly.
Step 2: With the dovetails removed, begin loosening the flat torx screws securing the dovetail to the dovetail plate.
Note: There are a total of six screws per plate.

Reassembly - 12S Battery Rack Assembly

Step 1: To reassemble a 12S battery rack, first align the dovetail with a dovetail plate, paying particular attention to the shape of the plate in reference to the dovetail.
Reference: Use Figure 30 as a reference if needed.
Note: If new dovetails are being used, M3 lock nuts will need to be inserted into the slots of the exterior of the dovetail before it can be secured to a plate.
Step 2: On a level surface, place two 12S batteries in the orientation shown in Figure 30 with the Tattu logo on the broadside facing inward.
Alignment: Place a dovetail bracket alongside both batteries, and align it with each battery.
Dowel Placement: Insert a plastic dowel between the battery and plate for the top and bottom of the right-hand battery.
Securing: Install all four screws and tighten each until the bracket is secured.
Caution: While installing the second bracket, be sure to prevent any misalignment between the batteries.
Correction: If a battery is misaligned, it will appear crooked on the level surface. Simply loosen each of the corner screws and tighten them once more.

Landing Gear Disassembly & Reassembly Guide

Overview

Instructions for disassembling a landing gear assembly and preparing it for reassembly.

Tools Required

2.5mm hex screwdriver
8mm socket
5.5mm socket
T10 screwdriver (for folding landing gear)
#30 drill bit (1/8 inch or 3.26mm)

Disassembly Steps

Remove Attachments: Remove any antennas present. Use a 2.5mm hex screwdriver for the clamping screw and an 8mm socket for the locking hex nut.
Remove Leg Bracket: Remove the M4x14 socket screws (M4x16 for folding gear) from the leg bracket to detach the landing gear assembly. Ensure the aircraft is on a stable surface to prevent falling.
Remove Through-Bolt: Secure the M3 lock nut with a 5.5mm socket. Use a 2.5mm screwdriver (or T10 for folding gear) to remove the M3x35 through-bolt. Retain the M3 washers.
Release Carbon Fiber Leg: Loosen the M3x8 socket screws on the landing gear clamp to release the leg.
Remove Tube Toe Bolt: Secure the M3 lock nut with a 5.5mm socket and use a T10 screwdriver to remove the M3x35 through-bolt from the tube toe. Retain the M3 washers.

Reassembly Steps

Reverse Procedure: Follow the disassembly steps in reverse (from Step 5 back to Step 1).
Bore Out Slots: Use a #30 drill bit (3.26mm) to bore out a slot for the through-bolt at the tube toe and the landing gear receiver.

Assembly and Disassembly: Payload and Dampening Assembly

To disassemble the payload and dampening assembly, begin by unplugging any wiring that may be connected to a sensor, camera, or gimbal, the generator telemetry cable, and the generator and fuel lines.

Disassembly

Step 1: Remove the M4x6 socket screws from the leg bracket to remove one landing gear assembly. Make sure the aircraft is placed on a surface that will prevent it from falling as legs are removed.
Step 2: Remove all four M3x8 socket screws from each Gremsy clamp.
Step 3: If maintenance is required on a Gremsy quick release, use a 1.5mm screwdriver to remove the quick release from the dampening plate.
Step 4: If replacement of payload rails is required, use a 2.5mm screwdriver to remove the M3x22 socket screws from each payload clamp.

EFI and Hydrone users: Payload rail tube caps should measure exactly 300mm from end to payload clamps when installed.
Fully Electric users: This measurement should be exactly 25mm from end to payload clamp.

Reassembly

To reassemble a payload and dampening assembly, follow the disassembly procedure in reverse from Step 4 to Step 1.

Assembly and Disassembly: Booms, Motors, and Propellers

Assembly and disassembly of the booms, motors, and propellers require additional considerations in regard to the overall balance of the propulsion system. This section discusses procedures related to disassembly, reassembly, and balancing in detail.

Disassembly - Propellers and Motors

Step 1: Remove the four Black T-Motor M4 screws securing the propeller to the motor frame and remove the propeller. Take note of the propeller blade orientation for reassembly (refer to the diagram on page 29).
Step 2: Remove the boom covers (with LEDs and/or antennas). Loosen the M3x8 torx screws located at the end of each boom and remove the cover enough to access the interior.
Step 3: Loosen the four screws securing the motor mount to the boom. Remove the motor mount bracket located inside the boom, as it is needed for reinstallation. Carefully pull the motor and wires through the grommet until the MR60 connector is accessible, then unplug the motor.
Step 4: To replace the motor, remove the motor mount by loosening the four M4x10 torx screws. Loosen each screw two turns at a time until the motor mount is free.

Reassembly - Propellers and Motors

Reassembly should be performed in reverse order, from Step 4 to Step 1.

Alignment: Align the motor mounting brackets with the fileted edge facing upward into the shape of the boom.
Fastening: Motor-to-boom mounting screws should not be loctited during this process to allow for maneuverability during the balance process.

Disassembly - Booms & Hinges

In rare cases, boom and hinge assemblies may require replacement. Due to a number of factors which may affect the flight characteristics, replacement of these assemblies by an experienced HA technician is strongly advised; these factors include, but are not limited to: frame balance, arm balance, and boom balance.

Doing so without prior consultation will void your warranty. It is recommended that if boom or hinge damage is present, the aircraft be sent in to our facility for repairs.

Step 1: In the event booms need to be removed, first follow the procedures listed on the previous page regarding propeller and motor disassembly.
Step 2: Next, remove the hardware securing the boom to the hinge, including: the hinge through-bolt, the hinge clamp bolts, and loosen the set screws on top of the hinge. The boom arm should now be free to remove from the hinge assembly.
Step 3: To remove the hinges, the aircraft should be placed on a surface capable of supporting the frame from underneath which allows the legs to be removed. Each leg is secured with four socket screws, and removal is required to access certain hinges. Each hinge is secured with eight M4 torx screws located on the top and bottom frame plates. Take note of the landing gear bracket (a T-shaped piece of aluminum) orientation for reinstallation.

Reassembly - Booms & Hinges

Step 1: Replacing hinges requires additional consideration for the balance of each frame arm; a dial indicator is recommended for accuracy. While reinstalling hinges, leave all eight screws loose and raise or lower the hinge while tightening each screw in a cross pattern. Use the dial indicator to measure the alignment of the inner frame to the end of the frame arm until the tolerance is no greater than ±0.005mm.
Step 2: Replacement booms require a .118 (3mm) drill bit to bore out the left and right side of the boom. This should only be performed once all other hardware is installed and the boom is seated. Ensure the boom makes contact with the back of the hinge receiver (inspect via port holes). To balance, use a meter stick level to align with adjacent and opposite booms, then reinstall and torque clamp bolts in sequence three times.
Step 3: Once booms are installed, balanced, and secured, reinstall set screws at the top of the hinge until they make contact with the carbon fiber. Finally, reinstall the through-bolt and its associated hardware (M3 washers, M3 locknut).

Balancing - Propellers and Motors

Balancing motor and propellers allows the propulsion system on HA aircraft to maintain efficiency while in flight, and prevents the accelerometer from having to make unnecessary adjustments for maintaining position. Balancing will require a small ruler level, a leveled surface, and patience. Balancing can be done with the propeller on or off, but to achieve the most accurate results, it's recommended that the propeller is off.

Step 1: With the motor mount screws slightly loose, small incremental adjustments will be made to the motor using an X and Y-plane reference. The X-plane (perpendicular) is controlled by the front two screws, while the Y-plane (parallel) is controlled by the rear two screws. In order to properly adjust the Y-plane, the X-plane must be set first and torqued in place, otherwise Y-plane adjustments are prevented. Place the level on top of the motor and determine which direction the motor will need to move in both directions (X and Y).

Step 2: Slowly begin tightening the X-plane screws while tilting the motor in the desired direction. Be careful not to crush the motor grates while making adjustments. Some overshoot may be required during adjustment to compensate for the torque of the materials acting in the opposing direction. When a balance on the X-plane of ±0.005mm is achieved, torque both X-plane screws in place.

Step 3: With the X-plane locked, place the level parallel to the boom, and begin adjusting the Y-plane using the same process as step 2. There is a chance that the X-plane will shift while adjusting the Y-plane if the required adjustment is large. In this case, steps 2 and 3 may require repetition several times until the desired balance is achieved.

Step 4: Once all motors have been balanced, it is recommended that a final balance check be performed with the propellers. To do this, install each propeller and fully extend the blades. Compare the tip of one blade to the adjacent propeller. Propeller tips should align flush with each other, have little to no angle, and be within ±0.01 of each other vertically. If propeller alignment is not ideal, balance procedures for booms listed on the previous page, and those listed on this page should be repeated until the desired balance is achieved.

Step 5: With all motors and propellers aligned, remove ONE screw from the motor mount at a time, loctite it, and replace it. Repeat this process for each screw that may have been adjusted during balance, which includes those associated with booms, motors, and propellers.

GP Assembly & Disassembly

To disassemble a GPS assembly (stand and puck), clip the zip-ties securing the CAN cable to the side of the aluminum stand, and disconnect the CAN cable from its respective port inside the aircraft (CAN Bus for GPS right, Pixhawk CAN2 port for GPS left).

Disassembly

Step 1: To remove the GPS puck, remove the M2.5x8 screw from the rear of the GPS puck and slide the puck off of the mount. Using a 1.0mm wedge or pry tool, remove the lid of the GPS puck. Disconnect the CAN cable from CAN port 1.
Step 2: To remove the GPS mount from the extension, remove the two M3x8 flat torx screws securing the mount to the top of the extension.
Step 3: To remove the GPS extension from the GPS stand, use a long M3 (T10) to remove the M3x12 flat torx screw from the center of the extension.
Step 4: To remove the GPS stand from the frame, use a 2.5mm screwdriver to remove the M3x10 and M3x8 socket screws from the base of the stand, while holding the bracket that resides beneath it.
Step 5: If removing/replacing CAN cables, cables should be routed through the interior wall section located at frame arm 1 and/or 2. The right GPS is typically routed to the CAN bus that is located at the front of the aircraft, inside the central airframe.

Reassembly

To reassemble a GPS assembly, follow the disassembly procedure in reverse from Step 5 to Step 1. While performing Step 4 the GPS stand bracket must be used to secure the stand in place.

Assembly and disassembly of the booms, motors, and propellers require additional considerations in regard to the overall balance of the propulsion system. In this section, procedures related to disassembly, reassembly, and balancing will be discussed in detail.

Disassembly - Propellers and Motors

Step 1: Begin by removing the four Black T-Motor M4 screws securing the propeller to the motor frame, and remove the propeller. Take note of the propeller blade orientation, as this will be important for reassembly. A diagram illustrating blade orientation can be found on page 29.
Step 2: Next, remove the boom covers (with LEDs and/or antennas). The screws (M3x8 torx) for each are located at the end of each boom. Once loosened, remove the boom cover enough to gain access to the interior of the boom.
Step 3: Each pair of screws securing the motor mount to the boom is fastened into a motor mount bracket located on the inside of each boom. When loosening the four screws that secure the motor mount to the boom, be sure to remove this bracket as it will be needed for reinstallation. With the motor mounts loose, carefully pull the motor and its wires through the grommet until the MR60 connector is accessible, and unplug the motor from it.
Step 4: To replace the motor, the motor mount will need to be removed and replaced onto the new motor. The motor mount is secured with four M4x10 torx screws that require incremental adjustments. Carefully, loosen one screw two turns at a time until the motor mount is free.

Reassembly - Propellers and Motors

Reassembly of the motors and propellers should be performed in order from Step 4 to Step 1. Be sure to align the motor mounting brackets with the fileted edge facing upward into the shape of the boom. Motor to boom mounting screws should not be loctited during this process, as this will limit the maneuverability of the motor during the balance process.

Disassembly - Plunger and Rack Alignment Assembly

To begin, remove the SLS E-Box walls and the avionics cover plate.

Step 1: Remove the four M3x8 socket screws at each corner of the interior basin.
Step 2: Lift the avionics cover plate out of the aircraft.
Step 3: Press the E-Box wall inward near the rack alignment wall to release the opposite side and pull the SLS wall out.
Step 4: Remove the six M3x12 flat torx screws (marked orange in Figure 29) and the mounting bracket to remove the rack alignment wall.
Step 5: Remove the single M3x12 flat torx screw at the rear of the plunger handle, along with the brass plunger pin and spring.
Step 6: Remove the two M3x12 flat torx screws at the rear of the plunger base and its mounting bracket.

Reassembly - Plunger and Rack Alignment Assembly

Reassembly should be performed in reverse order, from Step 6 to Step 1.

Mounting Brackets: Pay close attention to the installation of brackets for the plunger base and rack alignment wall.
Plunger Base Brace: Use the bracket with two slots for M3 square nuts as a brace for the plunger base.
Tech Tip: It is recommended to loosen the PDBs to slide the plunger base brace into place.

12S Battery Rack Assembly

To assemble the 12S battery rack, it is recommended that a level surface is used to prevent the batteries from becoming misaligned or bowing.

Disassembly - 12S Battery Rack Assembly

Step 1: First, remove the four socket screws located at the top and bottom of each dovetail bracket.
Note: Two screws will have a plastic dowel used as a brace between the dovetail bracket and the battery housing; take note of the orientation that the dovetail bracket is installed for proper reassembly.
Step 2: With the dovetails removed, begin loosening the flat torx screws securing the dovetail to the dovetail plate.
Note: There are a total of six screws per plate.

Reassembly - 12S Battery Rack Assembly

Step 1: To reassemble a 12S battery rack, first align the dovetail with a dovetail plate, paying particular attention to the shape of the plate in reference to the dovetail.
Reference: Use Figure 30 as a reference if needed.
Note: If new dovetails are being used, M3 lock nuts will need to be inserted into the slots of the exterior of the dovetail before it can be secured to a plate.
Step 2: On a level surface, place two 12S batteries in the orientation shown in Figure 30 with the Tattu logo on the broadside facing inward.
Alignment: Place a dovetail bracket alongside both batteries, and align it with each battery.
Dowel Placement: Insert a plastic dowel between the battery and plate for the top and bottom of the right-hand battery.
Securing: Install all four screws and tighten each until the bracket is secured.
Caution: While installing the second bracket, be sure to prevent any misalignment between the batteries.
Correction: If a battery is misaligned, it will appear crooked on the level surface. Simply loosen each of the corner screws and tighten them once more.