Extra precautions should be taken following an accident, including a crash, tip over, propeller strikes with solid bodies, or other abnormally stressing events. Contact Freefly Customer Support immediately after an accident for guidance as field inspections are no substitute for consultation and direct inspection and repair of damage by Freefly.
Freefly Customer Support can be reached at support@freeflysystems.com or by phone at +1 (425) 485-5500.
ALTA Pro is a precisely tuned flying machine with sensitive electronics and may become damaged or adversely affected by crashes, tip overs, propeller strikes with solid bodies, or other abnormally stressing events. Freefly recommends contacting Customer Support immediately for guidance in case of any of these events. Field inspections are no substitute for consultation and direct inspection and repair of damage by Freefly
Typical inspection points after an accident may include, but not be limited to, the following to gauge the flight-worthiness of ALTA Pro prior to subsequent flights:
Propeller blade and hub damage
Propeller tip spacing
Motor alignment
Chassis plate damage
The Toad In The Hole spacer in the center of the ALTA Pro
Booms for damage or cracking
Position light covers
Landing gear
Closeout panels
Hinge frame alignment
Hinge tension-compression link and latch
ALTA Pro’s motors are aligned at the factory at an angle relative to the chassis. This slight angle improves aircraft yaw authority and reduces the possibility of clockwise and counterclockwise turning motors from spinning at different speeds during stable hover. However, this alignment can be lost when opening the ALTA Pro chassis or if a boom needs to be replaced.
If the motors need to be realigned, follow the realignment procedure, then verify realignment was successful using the Pixhawk Flight Review software.
To perform a realignment, Freefly recommends using a small, digital angle gauge with a flat surface so it can rest on the bottom of the motor mount (for example, the Wixey WR300 angle gauge).
Place ALTA Pro on a level surface.
Place a digital angle gauge on the chassis next to the boom facing outwards.
3. Zero the angle gauge. 4. Starting at motor 1, place the digital angle gauge on the flat surface of the motor mount with the gauge facing outwards.
4. If the gauge reads a value outside the range 2.5°±0.1°, loosen the motor mount clamping bolts. While placing slight inward pressure on the motor, rotate the motor until the angle gauge indicates 2.5°±0.1°. When viewed from the end of the boom:
a. Motors 1, 3, 5 and 7 should be rotated clockwise.
When rotating the motor, do not pull outwards on it.
6. Apply threadlock as required (Loctite 222 recommended), and tighten the motor mount bolts to 0.8 N-m (7 in-lbs). Do not over-torque the bolts. 7. Repeat steps 2 through 6 for the additional motors. 8. After aligning motors, recheck motor mount alignment and clamping bolt tightness.
Complete Unpacking and Setup, Before Starting and Before Takeoff checklists.
Enter a hover for at least 10 seconds. Do not yaw during the hover.
Perform the ‘After Every Flight’ checklist.
Retrieve the microSD card from the GPS module and open it with a computer.
Open the ALTA Flight Data Viewer.
Drag and drop the latest .csv data log file of the test flight from the microSD card on to the ALTA Flight Data Viewer window.
Under the Data Seeker section, select Hover from the Seek Event drop down box.
In the Flight Statistics section, look at the Yaw CW Bias value. It should be within +/- 5%. It Yaw CW Bias is outside +/- 5%, recheck motor alignment.
Autopilot firmware is updated via the USB expansion port on ALTA Pro located in the chassis closeout between booms 1 and 2. To update firmware download the latest FW files from the ALTA Pro Firmware page and follow the instructions below:
Download the latest ALTA Pro FW from the ALTA Pro Firmware page on the support website.
Plug in a USB cable to your computer. Leave the other end unplugged from ALTA Pro for now.
Remove the chassis closeout between Booms 1 and 2 to reveal the expansion board.
Hold down the USB MSC Button on the expansion board while plugging in the USB C to the expansion board on ALTA Pro.
Enter the new folder now available in your file explorer. You should see a folder named FF-ALTA PRO.
Replace the ‘Freefly’ folder in the folder called FF-ALTA PRO with the new one downloaded from the Freeflysystems.com website.
Unplug ALTA Pro from the USB and then apply battery power while holding down the Boot button on the expansion board.
ALTA Pro should display a pink light to show it is updating its FW. Once complete the system will boot normally and display flashing green orientation lights and a flashing white status light.
Test radio channels, arming, and disarming behavior after firmware updates to ensure radio mapping has been preserved. Incorrect radio mapping can lead to loss of control.
Propeller blades should be removed when making a change to the configuration of ALTA Pro to prevent propeller strikes in the event of unintentional motor starts and should be replaced if they become damaged. Generally, a nick on the leading edge that is large enough to catch a fingernail indicates that the propeller should be replaced. If the blade composite structure becomes delaminated, the propeller should be replaced.
Freefly makes folding propeller assemblies available that include the blades and propeller hub fully assembled and factory balanced. They are available in clockwise and counterclockwise orientations.
Only use propellers supplied by Freefly on ALTA Pro. Use of third-party propellers can cause motor instability, overheating, and failure.
The folding propellers are installed on the motors with four M3×8 socket head bolts.
Always use a thread locking compound on the bolt threads that attach the propeller hub to the motor.
Odd numbered booms (1, 3, 5 and 7) use clockwise rotating propellers when looking from the top down, and even numbered booms (2, 4, 6 and 8) use counterclockwise rotating propellers.
Always check to ensure the correct propeller rotation direction and correct propeller prior to flight. Propellers that spin in the incorrect direction will cause ALTA Pro to be uncontrollable.
Under normal use, propeller bumpers (see exploded view figure on the next page) may split and fall out of the folding propeller assembly. Six spare bumpers are provided with the ALTA Pro. To replace the bumper, disassembly of the folding propeller is required.
Start by removing the M3 x 19 bolt and nylon nut. Pull off the upper prop adapter. The two bumpers are held in place by cylindrical features in the lower prop adapter. Replace the worn or split bumper.
To reassemble, follow the parts layout in the figure above. Note that there are two different types of washers, one made of nylon and the other made of PTFE. The nylon washer is smaller in width and thicker, and is installed between the nut or bolt head and the two prop adapters. The PTFE washer is wider and thinner and is installed between the prop blades and prop adapters.
Propeller blades are balanced and paired individually. Do not mix and match individual propeller blades when reassembling. Unbalanced propellers can affect flight performance.
ALTA Pro is designed to be as low-maintenance as possible.
It is recommended to check ALTA 8’s fasteners regularly. This check should occur roughly after every 15 flights, depending upon the level of vibration ALTA 8 experiences in flight or during handling. To check ALTA 8’s fasteners, apply a tightening torque to each fastener on the chassis using the supplied hex drivers. The fasteners should not slip.
If a fastener does slip, tighten it using the methods described in the Fastener Installation section. Do not apply additional thread locking compound unless the fastener has repeatedly come loose.
The following items should be checked after every 15 hours of flight.
Fastener Tightness
Check the tightness of the following fasteners:
Motor mount bolts
Prop hub bolts
Prop bolts
Top and bottom chassis bolts
Closeout panel bolts
FPV camera mounting plate bolts
Accessory mounting plate bolts
GPS/Compass mounting bolts
Inspect the following items. Replace if worn.
Propeller blades
Prop bumpers
Check hinge latching tightness by closing the hinge. There should be a firm closing force and click. Adjust the tension by using a 1.5mm hex wrench on the set screw located under the hinge latch.
Spare or replacement parts are available for sale separately at freeflysystems.com. Please refer to the store for a current listing of all available spare parts.
ALTA Pro ships from the factory with motors precisely aligned to minimize the difference in motor speed between clockwise turning and counterclockwise turning motors while in flight. Opening the chassis by removing the screws that attach either the top or bottom chassis plates affects this alignment and may reduce ALTA Pro performance.
All user maintainable items are outside the chassis and do not require the removal of screws attaching the top or bottom chassis plates.
Bolts and screws this manual identifies as needing to be removed or replaced do not typically require threadlocking compound. This includes the screws holding on the handle, battery retention strap studs, battery stops, closeout panels, and the top male Toad In The Hole adapter. In addition, fasteners that attach to nuts with a nylon locking feature (nylock nuts) do not require threadlocker.
All structural fasteners require the use of threadlock. This includes chassis screws, lower male Toad In The Hole adapter, motor attachment fasteners, and the four M3 x 8 socket head bolts that attach the folding propeller to the motor. Typically, a low strength threadlocker (such as Loctite Purple 222) is used on structural fasteners.
The Freefly hex drivers included with ALTA Pro are designed to limit the torque that can be applied to each bolt or screw and help prevent stripping the fastener head.
Thread all fasteners into their respective holes until snug (when the fastener head bottoms out and lightly clamps the two mating parts together).
To prevent excessive tightening and damaging the fastener or parts, twist the driver from the smaller diameter knurled section of the tool between your thumb and index finger for small fasteners (under size M3) or with your thumb and two forefingers for larger fasteners (size M3 and larger).
If the is unavailable or cannot be used on your operating system, yaw bias can be found at the bottom of the .csv data log for that flight.
Do not open the ALTA Pro chassis. Opening the chassis affects factory alignment.
