Yeyito (oz14618)

About this Plan

Yeyito. Control line stunt model. Wingspan 90 cm, for 2.5 cc motors.

Direct submission to Outerzone.

Quote: "Mary and Steve: It's been a while since I sent you anything, but I've had some time and that's why today is the time to send you the plans for the YEYITO, an old trainer in Spain that was the result of Modelhob (1967) and some new versions keep it in the memory and flying many practitioners of Circular flight. This undoubtedly also has significant sentimental value, it was assembled and almost finished by my brother who left us in 2015. I found it varnished and missing the engine and landing gear, friends like Paco, who told me He got an original Modelhob train, Fernando who made me his decals and Jesús who provided me with the support of the original command squad; I have been able to complete it and finish it [main pic, 003-006] and we have even flown it. Santiago took a license, making the wing removable with rubber bands and covering it in polyester vlis, it was logical since his love of free flight made the wing removable and its finishes in glossy varnish and a touch of bright orange (see his Uhu of RC, oz14159) was his style."

Update 18/5/2025: Added kit review from Aeromodeller, April 1984, thanks to RFJ.

Quote: "Modelhob Yeyito. John Stroud reviews a control-line trainer for 1.5 - 2.5cc. IT IS A VERY LONG TIME indeed since I built a control-line kit and when the editor offered me the job of reviewing the Spanish Modelhob 'Yeyito' kit I gladly excepted. Something easy, and relaxing to build over Christmas was exactly what I needed.

My guess is that the Yeyito kit has been around for some time. Not that that matters very much, but it is reflected in the recommended engine size of 2.5cc. With a hairy modern 2.5cc engine it looked fairly obvious the model would be fun, fast and furious for an experienced modeller. My intention was to look at the kit through the eyes of an inexperienced enthusiast. To this end I obtained a new Dav Cal 'Sabre' (1.5cc) and set about running it in very carefully because I felt I would need every ounce of power it is capable of giving. More later about this choice.

The Yeyito is supplied in a very attractive and stout box. Most of the information on the box is in Spanish, although it is easy to deduce the essential information of a 900mm span control-line kit for 2.5cc and the picture reveals it has a profile fuselage and built-up wings. On opening up the box one finds some very well cut wood, tissue, hardware and a comprehensive full-size plan. The hardware is particularly good, including a nice plastic fuel tank (non-aerobatic), dural undercarriage and wheels, tip weight, bellcrank and mounting bracket. My kit was an early import and supplied without instructions in English. (English instructions are now included). If one has built a few models this would not be a problem, but the inexperienced might find English instructions useful. The kit is a typical 'dry' one and needs glue, paint and fuel-proofer for completion.

Closer examination of the balsa showed it is well shaped, but that some was noticeably heavier than other pieces. The only place this would really matter is in the wings and I
put the heavier pieces to one side for use in the outboard wing. Unusually the ribs are supplied neither marked out nor shaped, but in straight strip which needs to be sanded to shape after assembly.

The fuselage can be glued together using a popular white PVA glue with little or no trimming of the parts. In my case I needed to modify the nose to move the bearers closer, in order to fit a smaller engine. Two strips of spruce did the trick plus a little extra 1A6in. ply. An alternative would have been to mount the engine on a dural or plastic plate then bolt the plate to the nose. This method also makes it easier to fit different engines. I left the fuselage under weights on a flat surface to dry.

The wings need some work and cannot be thrown together. The ribs are notched into both the leading and trailing edge. This job needs to be done carefully to make a satisfactory firm joint. First I marked out the notches exactly for width and depth noting that the trailing edge ones are at a slight angle. Cutting such notches out with a balsa knife is rather difficult and I prefer to use either a fine saw or a flat file. It is better to make them slightly tight and then open them up to fit with a small file. Those very cheap sets of small files are excellent for balsa wood (and ply) but not much good for anything else!

I covered the plan with cling-film and pinned down the leading and trailing edges after trimming the ends to the correct shape. Each rib needs to be cut to the exact length and glued in place. After all wing pieces had been assembled (except the wing joiner and part 25 next to the fuselage) they were left overnight to thoroughly dry. Next day they were sanded to the correct aerofoil shape..."

Supplementary file notes

Review.

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