Touchdown Delivery is committed to providing safe and reliable drone transport for America’s Businesses and Customers. The future of commerce is aerial!
Battery and ESC
1. By orienting the movement of the battery vertically, it is assured that the weight of the battery will produce a downward force on the connection with the drone airframe. One single 11,000 mAh battery is shown.
2. Air flows from the battery (primary cooling concern), to the Aft Motor Electronic Speed Controller (secondary cooling concern), to the Forward Motor ESC (tertiary concern). The reason the Aft ESC is more critical than the Forward ESC is because the aft propellers are 2” larger in diameter, so they require more power on average to accelerate; this creates a greater need to dissipate heat, and so it is best to position these two ESCs (left and right) where the average temperature differential is highest. The battery is the primary cooling concern because overheating could mean drastically shortened operational life for that battery - a critical factor in my economic model. While the ESCs are directly mounted to the ¼” aluminum arms, the battery unit is thermally isolated. For the ESCs, this works well because they are stationary, but a battery needs to be swapped. Additionally, I’d like to avoid the scenario where a fresh battery - cool to the touch - is inserted into a drone hot from flying in the sun. If the battery is not thermally isolated, then the heat will equalize with the battery right when the drone is ascending vertically, with a full payload. Because there is no horizontal movement during this phase of the flight, the three 120mm fans are active in keeping air flowing through the drone, including over the battery. The Touchdown Delivery App will prevent outgoing flights when local temperatures reach a programmed threshold. With this in mind, it is imperative that the Pilot City selected has a high annual average of flyable days.
1. One aspect that will change in V8.1 is the load cell. This load cell was selected when the overall design was much closer to the FAA’s 55 lbs upper limit. In addition to being too large, this design only left 0.08” (~2 mm) between the drone’s bottom surface and the top edge of the load cell. Although the load cell is mounted to a ridgid adapter, amd shouldn’t displace much even with a full payload, I’m concerned this small clearance will become a problem if any debris is kicked up into the crevice created there - creating a misread in the load cell that would cause the drone to malfunction when predicting flight range for a given payload. Because the Touchdown Network is node based, the drones must return to the retail outlet, small business, restaurant, or other origin they departed from. This is intrinsic to how Touchdown Delivery helps give those businesses a portion of the profit. Needless to say, initializing an outgoing flight that is too heavy to complete but was successfully launched by the user in the application due to a faulty sensor reading is a failure scenario that can be avoided with a redesign.
2. In this version, the aft downward facing UPS and landing laser are mounting using the same printed part that adapts to the load cell. This will still be the part grouping going forward, but with greater space between them.
1. Presenting the product favorably helps build sales - especially in a world increasingly conducive to sharing Kodak moments. Three sources of payload light (x6 5mm Ultrabright WA LED each) illuminate the interior. The lights also clamp down the fabric and rubberized foam padding that line the inside of the payload bay. The lights attach to the airframe without any metal fasteners.
2. Two neodymium magnets (along with drag forces) keep the payload lid secure during flight. The handle to the Battery Unit keeps the Payload Lid from rotating all the way forward. The seal between the forward/leading edge of the Payload Lid and the top panel of the Battery Bay is one of the focus points of the next design. Currently, a water resistant fabric tape could be used to breach this gap, but this wouldn’t be an aesthetic or acceptable solution. The likely solution will be an additional layer of rubberized silicone that fills in this gap but also allows for the full range of motion of the hinge.
3. By tilting on its forward legs like a wheelbarrow, the drone is easy to transport across the yard, through a parking lot, or up the driveway and into the garage.
1. Do you care about your privacy? I do. And I know the majority of residents would resent a company flying cameras over their backyard. That’s why my Touchdown Delivery Drones don’t even have a single camera on them - it’s simply not needed. Ultrasonic Proximity Sensing might sound incredibly futuristic, but the concept is simple. Similar to a radar system or a bat navigating the night sky, these sensors give the drone a sense of its surroundings during the two most critical flight phases - takeoff and landing. My system works by delegating “Big Picture” location sensing to GPS and “Local Picture” sensing to UP sensors. These two sources work in tandem to allow the drone to navigate effectively. The drone knows it has arrived over your property due to conventional GPS, but it senses the features of the terrain below with UP. With this two-part technique (and the help of your selection with the visible light laser), Touchdown Delivery can get goods to your house without intrusive cameras.
2. Printing still plays a strong role in the design, and will be used in the first series of prototypes. The Horizontal stabilizer should provide some lift, but I need to do some analysis on the next version to see if its really substantial enough to help. The Stabilizer also acts as a convenient handle.
3. Where do Touchdown Drones land? It’s easier to explain where they don’t! Fences, bushes, cars, and pools are locations that will cause a crash. A user who selects one of these locations using the landing laser might destroy or damage the drone if they don’t cancel the landing in time. While having cameras with image recognition would help address this problem, I don’t want to infringe on anyone’s privacy by even temporarily processing image data. This is one of the reasons you must have a valid Driver's License to create a user profile on the Touchdown Delivery app - should a user choose to land one of our drones in a pool, this is their destructive decision to make. In this case, privacy requires responsibility. Responsible users will be surprised by how many landing locations they can Laser-select around their home - the front lawn, the driveway, or any patch of dirt will work. To land on a somewhat trafficked street, Touchdown Delivery recommends centering the laser on the curb/gutter/reveal, so long as it isn’t higher than 6”. This splits the distance between the street and sidewalk, giving pedestrians and cars room to pass while you are unloading the drone. Never initiate a landing on a pedestrian or vehicle. Never initiate a landing when an unaccompanied child or dog is present. Unaccompanied cats are fine; animal research suggests they will act in self preservation, rather than a territorial display.
1. The forward face of the drone has three Ultrasonic Proximity sensors, which gives the drone 24’ +/- 2’ (7.3m +/- 0.6) range sensing ability to avoid obstacles in the forward, upward, and most importantly downward positions relative to the heading of the drone. Because the drone has no backwards flight mode planned for its core programming, it acts like a ray or vector and does not have need for an aft facing sensor. However, the upward sensor is necessary to prevent a crash if the user were to launch the drone from under a tree or beneath a porch, freeway overpass, or other obstacle. The upward sensor also prevents the drone from supplying any current to the motors if the lid is still open.
2. V8.0 uses the same wheels as V7.2, but solid mounting and an adjustment to the rolling axis have helped simplify the structure.
3. Rubber stoppers constrain the front legs when fully deployed. By bracing against the front arms, where the servos are also mounted, the amount of fasteners is reduced relative to the last version.