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Part# 05-00851
MFR Model# 254-AD


Delineates a procedure for determining where vortelators should be placed on an aircraft, for increased speed, by visualizing surface air flow through simple flight tests at straight and level flight at cruising speed. This kit is ideal for those aircraft models that do not have enough aircraft out in the field for Aircraft Development to economically warrant the time and expense of developing kits for.

Vortelator kit that can increase your homebuilt aircraft speed by 4 to 7.5 mph. This is accomplished by placing vortelators at certain critical locations which will cause the boundary layer to stay attached to flying surfaces for a greater distance, and to keep the boundary layer thinner. The net result of these two actions is that it reduces both the profile drag and skin friction drag components of the parasite drag. Another way to think of it is that the wake behind the aircraft will be smaller, thus requiring less horsepower to propel the aircraft through the air. Behind the vortelator mini vortices are created as can be seen by the lines of oil that form behind the vortelator. These mini vortices sweep the oil to a point in between the mini vortices, and thatís how the oil lines are formed. Whenever one sees these characteristic oil lines forming behind the vortelator one knows the vortelator is working. The vortelator allows the air flow to stay attached to the lift strut for approximately 80% of the lift strutís chord. In the area where there is no vortelator, the air flow separates from the lift strut and becomes turbulent, at approximately 40% of the lift strutís chord, as can be seen from the pile up of oil at the 40% chord position. At the 40% chord position the lift strut is 2.01Ē thick, and at the 80% chord position the lift strut is 1.18Ē thick. That means the turbulent wake coming off the lift strut is only 59% as thick with the vortelator attached as without the vortelator attached. That also means with a narrower wake less horsepower is required to propel the lift strut through the air.


  • My experience with the application of vortelators showed an increase in air speed of at least 5 MPH along with seemingly effortless acceleration and lower power requirement at each speed along the way up to top speed.

  • The installation of the kit was smooth and relatively fast compared to any other change to the aircraft I could have done to increase air speed. After washing the airplane, the installation of the tape-like vortelators took 3-4 hours.

  • My airplane is an experimental Thorp T18. It is the standard model, the original design, with the standard airfoil and body length and with.

  • The engine is a Lycoming O-320B2B 160 HP with a Sensenich WL 66-78 wood prop. The airplane reaches top speed at about 2650 RPM.

  • The landing gear has leg fairings but no intersection or wheel fairings.

  • I recommend this product for an easy and quick 5 MPH increase in air speed and less drag at all airspeeds in between. Better fuel mileage and lower fuel consumption are other ways to see benefits of this productís application to the T18. From K.N.

  • My Vanís RV-6A N614M was assembled and first flown in October of 2000. It was constructed following Vanís plans and recommendations, with only cosmetic and interior changes. It is powered with a Lycoming 0-360 180 HP (carbureted) engine, turning a fixed pitch (pitch 85) Sensenich propeller, model #72FM8S9-1.

  • I installed an Aircraft Development 254-RV6/6A Vortelator speed kit in October 2002. The following improvement resulted. My cruise speed at 2500 RPM, changed from 155 MPH to 159 MPH; an increase of 4 MPH. At the time of testing, the landing gear intersection fairings were not installed. I have been informed by Van and also by other RV builders that these add approximately 4 MPH, in addition to the numbers above.

  • When the vortelating material was installed on the propeller (from the center of rotation out 12 inches and the recommended distance back from the leading edge), I noticed immediate results. With the aircraft stationary on the ground, with no wind present, the RPM increased from 2150 to 2170 RPM. When in the air the top speed RPM increased by 25 (from 2800 RPM to 2825 RPM) and the MPH went up by 4 (from 199 MPH to 203 MPH). From M.T.

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