My-O-My (oz5768)

About this Plan

My o My. Radio control sport model.

Quote: "That Old Timer free-flight models converted to R/C make superb primary trainers has been widely recognized for several years. These old designs with their light wing loadings and high degrees of inherent stability, coupled with slow velocities, and relatively large size, provide the rank beginner with an opportunity to learn the rudiments of pilotage with a minimum of risk. My personal experiences, as well as those of the numerous builders who have written me, indicate the Old Timer type of models to be nearly perfect as trainers for those who have never previously flown R/C. These same characteristics also make these light, slow and large models highly attractive as sports subjects.

Sadly, the average Old Tinier design is not easily constructed by the beginner. The design and construction of these model aircraft from the 1930's strongly reflects the state of the art of that era - one must remember that epoxy, aliphatic resin, the glow plug, nitroinethane fuel, heat shrink covering material, etc were not available to those pioneer designers. The extraordinary flying ability and lovely appearance of those old designs attest strongly to their designers high skill levels with the techniques and materials available to them. The fact, nonetheless, remains that newer building and designing techniques can be used to create model aircraft possessed of the desirable performance traits of these antiques, while vastly simplifying construction and improving the durability of the model.

The My-O-My is an attempt on my part to create an Old Timer R/C type model, utilizing modern adhesives, materials, and techniques, while retaining those highly desirable virtues previously mentioned. That the My-O-My weighs 14 ounces per square foot, flies well on low power, has exceptional stability, and is startingly easy to construct, leads me to feel that indeed she is a 'new' Old Timer.

Her lineage has been a source of amusement for me. There are those who say she is a semi-scale Pober Pixie, or a Baby Ace, or maybe an obscure Old Timer or home-built. Others see an enlarged Q-Tee (oz1350) or a shrunken something-or-other. My reply to each claim has been: You are absolutely right.

Some readers may feel the structure of this model is too minima] to provide adequate strength, particularly in a mishap. Let us take a brief look at the philosophy involved. The collision survival of any model aircraft is a relationship between its structural integrity (strength) and the kinetic force delivered to its components by the object or objects with which it makes contact. Therefore, to render our models relatively 'crash resistant' we face a paradox. On one hand, if we design for strength by utilizing large wood sizes and numerous braces, we add to the total mass which, in turn, increases the kinetic force developed in a collision. Conversely, the deleterious effects of an excessively flexible structure are also obvious.

We, therefore, continuously walk a narrow line between strong and heavy, and weak but light. The My-O-My represents a reasonably successful balance of these factors, It is light enough to 'bounce' in the fashion of smaller 1/2A models, but also possesses sufficient structural strength to survive the rough handling to which such trainers are invariably subjected.

An effort has been made to provide convenient access to the systems of the model via the use of removable hatches, open areas, and a removable cowling. Nothing can be more frustrating to the flier than a malfunction of an inaccessible unit, Please note the pragmatic approaches used in designing the tank plumbing, landing gear mount. and the servo installation. Every effort has been made to follow the KISS, principles while remaining painfully aware of Murphy's Law.

The My-O-My incorporates building techniques that require only a flat building surface to create a true component, free of warps and misalignments. The builder need only follow the most basic tennants of craftsmanship to produce a model of which he can be justly proud. An effort has also been made to minimize the number of parts used; wood sizes and accessories are all standard stock items in any well stocked hobby shop, The wheel pants and landing gear unit are Sig catalog items and may be ordered direct or through your dealer. Only minor wood carving is required and parts fabrication can he easily accomplished with standard shop tools.

Although several innovative construction techniques are employed in the construction of the My-O-My. they are all well tried and of proven practicality and strength. Several of the innovations used will strike a familiar chord with anyone who has examined or built any of my previously published original designs and modernized Old Timers. Let's get to building.

General: The basic adhesive for this project is aliphatic resin. The epoxy joints should be made with slow cure type. however, several My-O-IM's have been constructed using 5-minute epoxy with no deleterious effects except some weight build up. Do not substitute balsa for spruce in the wing, nor spruce for balsa in the tail. The cut-outs in the fuselage sides are not needed unless a very light engine is to be used. For a ST, K&B, or larger Fox, the model will tend to be nose heavy anyway.

Fuselage: Place 1/8 lite ply under the fuselage side view with carbon paper placed to create a tracing on the wood, Use a straightedge and a pencil to trace over the drawing. Cut straight lines with a knife and the curved lines with a Dremel or coping saw. Use the first pattern to develop a second. Lightening holes are created using a hole saw to cut through, then connecting holes with a knife and straightedge..."

Direct submission to Outerzone.

Update 16/01/2015: Replaced this plan with a clearer copy, thanks to theshadow.

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