As we start prepping for our next test flight, we have set incremental goals to achieve. We will add a more efficient cooling system to our power supply, add two more battery packs and larger gauge cables.

For the electronics, we will create a few different throttle profiles and test which will perform better under heavy loads. Our current profile is non linear which performs quite well when the Crossbow is not loaded. However, this profile seems to have a bit more lag with input response when carrying a weight. Our next test should help us determine a more optimal throttle curve for both scenarios. 

Next on our list is to add more weight to the Crossbow and test its weight capacity further. During our last test, we achieved a partial load test of 138.8 lbs. We hope to increase this weight a bit more until we achieve a real-world load test at 100% throttle. 

We are also planning to add two more motors and propellers to the Crossbow in order to increase it’s payload efficiency— meaning achieving the same heavy payloads while decreasing the need for throttle input. This will help maintain greater power reserves incase more power is needed for a quick altitude change or obstacle avoidance while in flight.   

More to come. Stay tuned!


We had a chance to perform a load test on the Crossbow this past weekend. We’ve added additional cable supports and a landing apparatus which helped reduce the torquing issue evident in the initial test flight. We’ve decided not to reduce the chassis weight at this time because the extra weight will help us with load testing. 

The weather conditions during testing was a bit windy at about 8 mph, but since we weren't planning on doing more than 3-4 ft hover mode, we continued with our tests. 

During the first flights, it was evident that the initial torquing issues had been reduced significantly. The landing apparatus is made of 2" PVC piping and attached to each pair of arms like an outrigger. It was strong enough to counteract the torquing effect yet flexible enough to reduce landing impacts. 

The hover tests were successful and didn’t seem to tax the chassis and motors much at all. Towards the last test flights of the day, we decided to increase the takeoff weight by adding sandbags to simulate a partial load. The total take off weight has now been increased to 138.8 lbs (62.9 kg).

After clearing the area and going over pre-flight safety checks, I decided to do a light hover where the airframe was still in contact with the ground, but the motors were working hard enough to yaw the drone and pivot. This allowed me to “trim" the controls (micro adjustments) to respond better to the current wind conditions. After I've trimmed the controls and the drone was stabilized, I was ready to proceed with the hover test under load (138.8lbs / 62.9 kg).

As I increased the throttle, the loaded airframe slowly lifted off the ground. At takeoff, it seemed as if the motors were applying significant effort under the load, but after the entire airframe lifted off the ground, the motors did not seem to be applying much effort at all. 

All-in-all, the test was quite successful! Our next step is to take all the data we’ve gathered and improve upon the electronics as well as the overall structural design. 

I will also start developing concept designs and sketches to illustrate how the fairings will look as we work towards the final design. Stay tuned!

Maroon Vault

We Are MAROON VAULT - The small Industrial Design company who built a giant drone! 

We are a Product Design and Vehicle Concept Design Company based in Hollywood, Los Angeles, California. We have designed and worked with notable companies such as Suzuki Motor Company, Kia Motor Company, Company Films for Renault Motors, Hawker Beechcraft, LG Electronics, T-Mobile, Verizon, Sprint, Mattel and more. 

DRONE PROJECT | The Crossbow

The Crossbow Drone is our Halo Project, something to showcase our design skills; we are known for designing aesthetically pleasing products, but this time, we wanted to show that we can design something very complicated with very little. I came up with the task to build a giant drone specifically designed to aid with Search & Rescue for our booth at CES 2018. 


We have received a great amount of support and positive feedback from those who saw our drone project and would like us to continue with further development. We plan to go to and create a campaign in order to raise funding for parts and more safety features for our drone project.