Dehavilland Beaver DHC-2 MK I
Safety & Performance Enhancement Kit

Vortex Generator installation significantly improves flight characteristics and safety of the DeHavilland Beaver.

The Problem:
During our flight test program we found that even though the Beaver is being operated within limitations, there are some very undesirable flight characteristics that occur under certain conditions. Aircraft wings are designed so that a stall will begin at the wing root and propagate outward in a controlled manner. When heavily loaded with a forward CG, the stall characteristics of the Beaver conform to this principal. However, as the CG is moved to the aft side of the envelope, the stall characteristics become completely unacceptable because the entire wing stalls at the same time. Aileron and rudder control remain effective up to the point of a stall but they are simply not adequate to control the aircraft once a stall has occurred. When stalled in this condition, the aircraft will violently roll 60 degrees, yaw 30 to 40 degrees, and pitch down 30 degrees. A very aggressive, positive elevator movement is required to recover from the stalled condition before impending spin entry. These negative characteristics were found to increase with the use of flaps, and existed consistently in wings level, turning, and accelerated stalls. The fact is, when stalled in a heavy, aft CG condition the pilot will more than likely loose control of the aircraft. Time and time again this has proven to be the cause of Beaver accidents. Our Vortex Generator Kit has been designed specifically to address this problem.

The Solution:
The installation of our Vortex Generator Kit completely changes the stall characteristics of the DeHavilland Beaver. In all flight configurations, with the CG located anywhere within the envelope, power on or power off, and with flaps in any position, the negative characteristics described above are completely eliminated. Aileron and rudder control remain effective even in a stalled condition. While in a stall the pilot can hold the elevator in the full up position for several seconds.

When set in pairs Vortex Generators create counter rotating vorticies

Description of Kit Parts:
The photographs below show the parts and positioning of the BLR Vortex Generator Kit on the DeHavilland Beaver DHC-2 Mk I. The parts shown are the prototype parts used for flight testing and certification of the Vortex Generator Kit. The production Delta Wings are fabricated from fiberglass, the Vortex Generators are aircraft grade aluminum extrusion. The entire kit weighs less than 2 lbs. and easily control bank and yaw with aileron and rudder input. Stall recovery can be made by simply relieving back pressure on the elevator. The Vortex Generators also significantly improve slow speed controllability of the aircraft and give small reductions in stall speeds.



The kit consists of four Delta Wings (two on each wing) and six pairs of Vortex Generators on each wing. This photo shows the outboard Delta Wing and the six pairs of Vortex Generators. The parts shown have been temporarily installed using aluminum tape. On a permanent installation the Vortex Generators are glued in place, the Delta Wings are glued and riveted in three places.

The Delta Wings are mounted at the leading edge of the wing. They are approximately 10" long by 5" wide and stand about 2" high. The inboard Delta Wings are positioned just above the junction of the wing strut and wing. The outboard Delta Wings are positioned directly forward of the flap/aileron junction.