By John Steere
The accompanying photos document the fabrication and assembly process used to build the wings for BD-4, N682BD. The wing design is by John Raffensbarger of Monkton, Maryland, and is an aluminum adaptation of the BD-4 airfoil, originally executed in fiberglass panels. John sold plans and a limited number of specialized components under the business name of J.R.s Metal Works Inc. J.R.s Metal Works has been dissolved, but he still sells the plans. John can be reached at 410-343-1079.
John’s plans are for the wing only, assuming the builder would construct the flaps and ailerons according to the BD-4 plans published by Jim Bede. The wing portrayed in the photos was assembled following the step-by-step instructions in John’s plans. The wings are extended 22 inches per side as described in Jim Bede’s optional wing extension plans.
The photos also depict the fabrication and assembly of the flaps, ailerons, and internal systems. This wing departs from any published plans at this point as the flaps, fuel, vent system, landing light system, and other accessories are added or modified to meet unique objectives for this airplane.
The flaps have been modified to reduce the landing speed by extending them 22 inches per side, and increasing their maximum deflection from 30° to 40°. This increases the load on the flaps, their mounting points, and the actuating mechanism. To handle the additional loads, an aluminum tube was added in the leading edge of the flaps, and two Delrin bearings were added along the span. The internal coupling to the flap actuator was strengthened by adding a steel rib on the inboard end, and extending the coupling through three ribs. With the extended flap length, additional ribs would be required, so the choice was made to change to aluminum ribs in the flaps, but retain the wood ribs in the ailerons.
Also included is a PDF file of a drawing for a wing rack that has proven to be very useful. With this rack, wing installation and removal becomes a one-man job. Since it is common to install and remove the wing many times during construction, it is highly recommended.
I have also included a few photos of the engine installation, the interior, and information related to the radiator and its belly scoop.
I hope that the ideas captured in these photos are helpful. If you have questions, the preferable communications mode is through the e-mail list (sign up at http//northwest-aero.com/arcbd4/) so others can benefit from your questions.
List of the image pages:
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