The Hornet LR Gets an Upgrade

The Hornet LR with Elevon Extensions

The Hornet LR with Elevon Extensions

Our latest version of the Hornet fixed wing drone features a brand new aerodynamic upgrade in the form of our unique elevon extensions.  Elevons are the moving control surfaces on the trailing edges of the wings that allow a flying wing to maneuver through the air.  The original hornet airframe wasn’t intended to carry the increased payload weights of the newest long range variants which carry additional batteries and sensors; this meant the aircraft occasionally stalled on takeoff and executed rather fast & hard landings.  The Agribotix airframe architecture team engineered a solution that increases lift on takeoff without increasing drag in cruising flight.

Increasing lift usually means longer wing-spans or flaps.  Longer wing-spans create extra drag when the airplane is at its cruising speed whereas flaps add weight to the airframe and complexity to the avionics system.  The solution lies in an often overlooked dynamic of small unmanned aviation systems [sUAS] like the Hornet: the airframe weight is a less significant contribution to the overall aircraft weight than would normally be the case with full scale metal/wood/composite manned aircraft.  This is because the Hornet airframe is made of foam: adding more weight to its airframe contributes very little to the overall weight of the aircraft.  This means that conventional models of wing length-to-width [aspect] ratios, designed to minimize weight while maximizing lift for large manned aircraft, don’t apply to small foam sUAS systems.

The solution was to fix the original elevons in place and create 'elevon extensions' that increase the lift area on the Hornet's wings.  To be sure, these elevon extensions did increase the weight of the Hornet LR, but by an amount that was so insignificant as to not detract from the two advantages they brought to the table: increased lift area and more efficient aerodynamic airflow over the airfoil.  Because the wings were not 'lengthened' they don’t create any more drag than before and in fact reduce overall drag by reducing the angle of attack at cruising attitude from about 8° to 5°. 

Airflow Modification

Airflow Modification

An additional advantage is that the new Hornet will stall at a slower speed than the previous hornet, effectively giving the onboard flight control computer an ability to attempt landings at slower speeds.  This will reduce wear and tear on the airframe and lead to a longer lifespan for the sUAS system as a whole, while increasing the margin of error the flight control system has when navigating sudden wind gusts on takeoffs and landings.

 

Contact us at Agribotix if you’d like to find out more about the Hornet Long Range and how it can help your drone imaging program be successful.