Mira 3 (oz16092)

About this Plan

Mira 3. Radio control scale glider model. Wingspan 3000 mm. Scale is 1:4.5.

Quote (google-translated): "In the course of my incessant search for rare and unusual subjects, the choice fell on a 1924 Czechoslovakian glider that I discovered in a volume donated to me by the Czech team during the Retroplane 2011. Its shapes so out of the ordinary won me over immediately. The book entitled 'Bezmotorova letadla v Ceskoslovensku 1918-1939' (Czechoslovakian Engineless Aircraft 1918-1939) is full of subjects so out of the ordinary that won me over immediately, with 3-views and period photos.

The MIRA-3, in particular, was designed by Col. Rudolf Holeka and presented at a competition in Medlanky (Brno), in 19M. The flight lasted very little because the machine, which had the aerodynamic finesse of an iron, was damaged during landing. For some, this would already be enough to give up reproducing such a 'trap', but not for me. On the contrary, these challenges motivate me and then the MIRA-3, with those folded wings and the pot-bellied fuselage, seems an unlikely cross between a swooping tern and a dolphin. Also noteworthy are the two large wheels and the fully glazed cabin, something quite rare at that time.

THE CONSTRUCTION: It is worthwhile to point out that this model does not claim to be an absolutely faithful reproduction. The documentation is too scarce to be able to do so, but I tried to get as close as possible to reality by working on the Cad with the 3-views and the original photos. The attached drawing has been reduced for typographical needs. It must be cut along the dotted line and the four resulting plates enlarged by 300% at the copy shop. You can check the correctness of the enlargement by measuring the printed scale which must be 200 mm long.

The fuselage is composed of two sides in the shape of an airfoil (similar to the GO 614) without frames and of constant width. The sides are built on the plane: the outline is a laminate of three layers of 3x10 pine pressed with eccentric wooden disks around a chipboard shape covered with insulating tape to prevent the wood from gluing to it. After everything has dried well, the laminates are sanded until they are 8 mm thick.

At this point the outline is fixed on the plane protected by transparent plastic and the nose is glued in 8 mm plywood and the vertical crosspieces which are 8x8 pine up to the trailing edge of the wing and 8x8 balsa up to the tail. The two sides are joined with 8x8 pine crosspieces in front and balsa at the back. Thanks to the constant width of the fuselage there is no need to 'staple' anything.

The main landing gear supports are made of 4 mm plywood, reinforced inside by 1.5 mm plywood gussets. The suspensions are hydraulic rubber joints that join the 5 mm steel wheel axle to the lower crosspiece, made of 3 mm steel. The fin ribs are made of 3 mm balsa and the base ribs are made of 3 mm plywood, the uprights are made of 8 and 10 mm balsa while the trailing and leading edge contours are made of 0.6 plywood. The assembly is done in the air, positioning the contours in the slots of the uprights and inserting the ribs. On both sides of the contours, bottom and top, I glued a balsa filling that was subsequently shaped. The fin is fixed to the base of the fuselage with two offset screws that enter the holes in the base: then it is rotated into position and the screws are tightened..."

Direct submission to Outerzone.

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