After debuting Snap back in September, our engineering team has been in full force testing the product and ironing out the design details. We’re determined to make Snap the most advanced flying camera possible, and that means improving and upgrading certain design aspects right up until it goes into final production.
On that note, today we announce a new rotor set design (the rotor set is the folding assembly that has the four propellers, motors, and guards which attach to the body). As much as we loved the original metal-spoked design, we decided to consider an alternative prior to locking in on the final production design. After countless hours of testing, and greatly improved performance, we are pleased with the new design. Here it is:
This new design replaces the original tensegrity structure created by the steel spokes and replaces them with unidirectional pultruded carbon spokes on the bottom. These new spokes offer a number of advantages which will ultimately improve the following:
- Overall Weight
- Wind Performance
- Thrust Efficiency
Because carbon fiber has about 1/7th the density of steel, we can make the spokes larger without increasing the weight (actually, this new design shaves off 15 grams). The larger spokes themselves also offer a few advantages:
First of all, the deeper cross section (3.9 mm instead of 0.3 mm) increases the Reynolds Number of the flow over the spokes, which reduces the energy lost in the turbulent wake behind the spoke. This change translates to longer flight time and improved stability in the wind. We can also get away with using fewer overall spokes, which further improves wind performance and efficiency.
Additionally, the stouter structure of the carbon spokes can bend (like a bow) on impact with the ground, which allows the form to absorb greater amounts of energy. Snap can now hit the ground harder without breaking (we tested this by adding weights to the rotor sets and dropping it from a 15-foot deck onto the concrete below).
One of the biggest challenges with this design was understanding how to effectively secure the ends of the spokes so that they could bend smoothly without breaking. After several months of careful material selection, finite element analysis, drop tests and revisions, we found a combination of soft and flexible materials in the hub, and stiffer materials in the rim, which have withstood even the hardest of our drop tests.
With this final design change complete, we are now preparing for the tooling release on March 1 and will begin the assembly and test of final units in late April. The new design also offers a host of manufacturing benefits – massively reducing the number of unique parts – which will help get Snap to your doorstep faster! This leaves us on track to begin deliveries at the end of spring, in early June.
We have a number of other exciting updates coming soon, including a flight time announcement, a new office space and sharing flight video from our 4k camera, so stay tuned!
As always, thank you for your support.
— Tobin and the Vantage Robotics team