Dosalas (oz15387)


Dosalas (oz15387) by Pat Tritle 2021 - plan thumbnail

About this Plan

Dosalas. Free flight sport biplane model, for rubber power. WIngspan 21 in, wing area 139 sq in.

Note this plan is a free download available from the Model Aviation site at where it appears along with full materials list, complete build text and some excellent build pics. Also a free download of the plan in tiled format.

Quote: "I am a big fan of biplanes, but in the Free Flight (FF) realm, setting up a conventional biplane can be a challenge. Because I wanted to create a simple FF biplane without the typical complexity of a conventional setup, I decided to go with a cabin-type fuselage with I-type interplane struts to make the setup nearly foolproof. The result is a fun little sport FF model that is easy to build and will fly well, even in small venues.

The Dosalas is of the conventional stick-and-tissue style of construction, covered with tissue and dope. The lines are straightforward, so the model is not only fun, but it is easy to build. It is also easy to cover for those who have less experience with old-school covering methods.

One unique feature of Dosalas is its universally adjustable nose block. The setup allows for any combination of side- or downthrust that will allow even minute trim adjustments to be made quickly and easily. The adjustable nose block requires fabricating a couple of metal parts, but the parts can be made easily using simple hand tools. And with that, the only thing left is to build the model.

Building the Dosalas: Patterns, wood sizes, and quantities are provided for each of the shaped parts, which are cut from 1/16-, 3/32-, or 1/8-inch balsa. The nose block is cut from 1/2-inch balsa.

Building the Vertical and Horizontal Stabilizers: The vertical and horizontal stabilizers are built directly over the construction drawings. The model was laid out with either a straight or swept vertical tail, so decide which one you prefer and build it accordingly. Construction is entirely from 3/32-inch square balsa. With the frames completed, lift the assemblies from the board and sand to shape.

Wings: Both wings are identical and are built directly on top of the plans. Begin by pinning the 1/16-inch square balsa bottom spars in place over the plans. Fit and glue ribs R2 to R5 in place on the spars, followed by the 1/16 × 1/8-inch balsa trailing edges (TEs) and 1/8-inch balsa leading edges (LEs).

When dry, remove the wing panels from the board, place an 11/16-inch block under each W5 rib, and pin the panels back in place. Fit the 1/16-inch square balsa bottom spar in place, followed by the W1 ribs, the LEs, and the TEs, and glue in place.

Fit and glue the 1/16-inch square balsa top spars in place to complete the assembly. When dry, remove the wing assembly from the board and sand to final shape then build a second wing in the same fashion.

Fuselage: Begin by pinning BWS, MPM, and the 3/32 × 1/8-inch balsa top wing saddle in place over the plans. Add the remaining 3/32-inch square balsa longerons and vertical and diagonal bracing. Fit the 1/16-inch balsa fill at the front end, flush with the board. Build the second side frame, but on this one, the front sheeting will be flush with the top edge..."


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Dosalas (oz15387) by Pat Tritle 2021 - model pic


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