With the constant need to overcome the challenge that is the African landscape we now had to break from convention yet again – by implementing outer wing sections on our UAVs that can lower during take-off and landing!
After intensive research into what a UAV would need to be able to do in the challenging and harsh terrain of the African bush, we have decided to take a further step into exploring this daunting and non-conventional concept due to the following the following –
Most crucially there is need for autonomous Vertical Take-off and Landing (VTOL).
For the UAV to remain battery powered and maintain the desired airtime, at some point it would need to land and take on fresh batteries. Continuous return trips to base for battery changes would reduce efficiency, so our vision required an adaptable plan, which included landing and taking on batteries at multiple locations. However, we cannot have a pilot available at each location, so the UAV needs to be able to land and take-off again with minimal assistance.
Autonomous VTOL does itself require wings to be dropped BUT a VTOL fixed wing may encounter many potential complications during VTOL that adds complexity to a crucial stage of the flight.
The first problem is ground effect – which is an increase in aerodynamic lift, coupled with a decrease in aerodynamic drag that the wings generate closer to the ground. Add in gusts of wind or wash from large VTOL rotors and the result will likely be a UAV that is extremely skittish and hard to control when closer to the ground.
As a result, the motors may have to work extremely hard to try stabilise the UAV and in extreme cases, the UAV may even cartwheel if the motors cannot provide enough stabilisation.
Our amazing engineers, David van Der Merwe and Carel Kriek helped develop a system where The Eye Above’s UAVs have wings that are divided into almost two equal parts, with the front motors located at the junction of the wings. Dropping the outer wing does not eliminate lift but it does change the lift patterns; meaning that our front motors do not have to work as hard when attempting to stabilise the UAV during close proximity to the ground. VTOL fixed wings need landing gear to land. Normally, the choice is between fixed landing gear or retractable landing gear. In both cases the UAV must be far enough off the ground to prevent debris from being propelled up into the front propellers. In the case of retractable landing gear, this becomes challenging. where fixed landing gear is concerned, there is the potential that it can block the views of 360° rotational cameras.
By adding landing skids to the wing tips and utilising the mount as a shock absorbing mechanism, we simply use the lowered outer wings to double as landing gear. The wing will lower automatically to the landing position. This effectively solves two problem with one solution. We have a mechanism for landing that allows for clear camera views, and it is simple and effective to provide the necessary ground clearance too.
There is even an added benefit when it comes to transporting of the UAV. Once in landing position, it is then possible to unclip the mechanism and fold the wings under the UAV for transport. This also makes deployment faster, because there is no need to disconnect wiring when transporting the UAV.
We are also evaluating designs for a system that will allow the wings and tail boom to fold and unfold from transport position meaning that the UAV can unfold and autonomously deploy from a pod.
Let us know what your thoughts are on this interesting new development and how you think The Eye Above drones are making a difference to Rhino Poaching attempts in Southern Africa.
We appreciate your interest and look forward to sharing further insights and project updates with our interested supporters in our ongoing journey!