IFlight have partnered with Chris Rosser to provide the manufacturing and shipping of his design.
The AOS 7 is optimized to deliver maximum flight performance on 7" props. Aggressive freestyle and long range cruising; this frame can do it all.
The AOS 7 builds on the scientific approach used to design the AOS 5 and AOS 5.5 extending the benefits of those designs to the 7" class. Until now 7" quads have been primarily used for long range cruising and have never been able to match the performance of 5" quads for aggressive freestyle flying.
That all changes with the AOS 7. Designed to match and even exceed the vibration performance of premium 5" frames this frame can deliver thrilling freestyle performance and long range cruising, the best of both worlds. The efficiency of 7" props are perfect for longer freestyle rips 5min+ or long range cruising for 10 - 20minutes or even longer with Li-Ion 18650 packs.
A combination of finite element simulation and real-world flight testing gives this frame exceptional vibration and resonance performance. This means you can run less filtering and higher PID gains for a smoother and more responsive feel with greatly improved mid-throttle oscillations and cool motors.
- Approx. 230g with all hardware
- Designed for 7 inch props
- 8 mm Arms
- 2.5 mm Top Plate, Bottom Plate and Sandwich Plates
- Three 30.5x30.5 mm or 20x20 mm stacks in the front, middle and rear
- Recommended motor size 2806.5, 30mm
- Standoffs, frame and motor screws included
Vibrations Limit Performance
As a pilot I often struggled with Jello, mid-throttle oscillations and propwash handling on my freestyle quads and the problem only gets worse as the quad gets larger. As an aerothermal engineer I realized that the issue lay in the vibration and resonance performance of the quadcopter frame itself.
Even the cleanest motors and props produce large amounts of vibration in flight. These vibrations excite the resonant modes of the frame amplifying vibrations at certain frequencies, increasing their amplitude and energy. These vibrations pass into the gyro and create noise on the signal. This noise requires additional filtering and limits maximum PID gains through motor heating.
The result is a flight controller that is slower to respond to propwash and your stick inputs. The AOS 7 is designed to be better.
Harmonic analysis is the key
I used Blackbox logging and harmonic analysis to visualize the vibrations of the AOS 7 during the design process. This allowed me to tune the geometry of every part of the frame, moving the frame resonances up and away from the motor frequencies and separating them as far as possible. This avoids, as far as possible, the situation where the motor frequencies match a frame resonant frequency and so amplification is minimized.
As a result, you can run less filtering. Every layer of filtering adds delay that’s mathematically related to how effectively it removes vibrations. This delay prevents the flight controller from responding rapidly enough to propwash leading to poor propwash handling. Reducing the amount of filtering is the best way to improve propwash handling. With the AOS 7 you’ll be in the best possible position to reduce your filtering to an absolute minimum.
Another advantage of lower noise is the ability to run higher PID gains. Higher PID gains allow the quad to track your stick movements with less delay and more precision. The result is greater confidence, particularly when flying tight lines where fast reactions are vital.
Top and bottom plates
Both of these plates are 2.5mm thick to provide an optimal balance between strength, stiffness and weight. The cut outs in the top and bottom plate of the AOS 7 are tuned using finite element analysis to preserve as much of the bending and torsional stiffness of the plate as possible whilst minimizing weight.
There are mountings for three 30.5x30.5mm or 20x20mm stacks with plenty of space in between for the receiver, capacitor and other accessories.
The AOS 7 uses the same distinctive truss design for the arms as the AOS 5 but takes it to the next level. Each arm is made from two parts that interlock together. This allows both struts of the arm to be cut with the fibers aligned along the length of the part maximizing the material stiffness and strength in every part of the arm. The truss design provides enormous torsional stiffness and also allows two particularly harmful resonant modes to be individually modified to separate them in frequency.
Truss structures are inherently very strong as they convert bending loads into compression and tension in the individual members. Carbon is much stronger in pure tension and compression than in bending.
Y-shaped motor protectors minimize the risk of damage to those expensive components. Should you ever need to replace an arm, there are only two screws to undo and neither are shared with your electronics.
I would like to give credit to Julianus and Bob Roogi who independently contributed elements of the design.
The AOS 7 uses 2.5mm Carbon Plates to hold and protect the camera. These are stiffer, lighter and cheaper to replace than aluminum or titanium.
The camera plates include 2 standoffs to maximize durability and a cutout pattern that supports DJI O3 and all typical19-20mm FPV cameras.
GoPro Mount and 3D Prints
The GoPro mounting pattern on the AOS 7 is identical to the AOS 5 and AOS 5.5 so any mount designed for any of these frames will fit and work perfectly on the others.
The GoPro is secured by 4x M3 screws into aluminum standoffs so you can be confident that the mount will not be going anywhere in a hurry.
I've designed some example prints for DJI antenna mounts and 18mm GPS.
If you would like to print the models yourself you can find them at Thingiverse HERE!
- 1 x AOS 7 O3 7" Long Range FPV Drone Frame Kit