The history of this plane, including photos, 3-view, color scheme and plenty of other information can be found in Schneider Cup book by Lubomír Koutný. During the contest the plane was all in blue with brown floats and white starting number 10. I first built this type as peanut. Small light peanut flies very well, in Pardubice it reached times over 85 sec and peanut flew just under the roof construction in about 17 m, gliding at the end of flight, maybe slightly longer and thinner rubber would help...
When Bernard Getz attached additional competitions to OPENSCALE 2008 (among them also FLY OFF for Schneider Cup planes) I decided to build Borel in 1/20 scale. The model is succesfull, it is very light (18g without rubber). First trimming flights in Medlanky proved that all the angles are correct and model was flying exactly as built.
1/20 scale Borel
Is available in PDF format. The plan is reduced to 2xA4. After printing it must be scaled on copy machine to proper size and measured - guys at copy center can make an error. So just to make sure, the wingspan of the model is 470mm and length of the fuselage without the propeller is 320mm.
There are no specialities during the building, so the instructions are brief. Fuselage is built from two side frames made of 2x2mm balsa spars. Front former is made from 4mm balsa. Half-formers are used for rounding the front on both upper and lower side. The floats are built in the same manner, spars 1.5x1.5 from very light balsa. Add 0.5g of lead to the front part of each float. The wing is of common design, the tail as well. The propeller has blades from hard 1.5mm balsa bent on hot iron. Its pivots are made of bamboo 1.5mm put into paper tube. The shaft is made of steel wire 0.8mm. Model completation is a bit tricky, try first everything prior to covering, glue the wing holder into the fuselage, with V shape for both spars and leading edge. Floats are covered by brown modelspan, the rest by blue japan. Wing and tail should be painted in template and left there for at least 24 hours. The struts are made of very strong balsa. First glue front and back M. Those are put onto the floats and finally we glue the struts to fuselage. Wire struts are made of finest fishing line. Rubber band is made of six threads of 1.6g/m TAN SS 05 rubber, 450 mm long. Maximum is about 1500 turns at 25 oC. All the angles must be according to the plan, including negative on right half of the wing, propeller angle to the right, etc. There are many angles to check and all must be correct! The COG with the rubber is at about 45% of wing chord. Correctly built model is easy to trim for flights as no trimming is necessary. First we glide the model on calm day, driven flights should start at 600 turns, sequentially increasing, the model should nicely climb in open turn.
I wish you many nice experiences and success on competitions.
ing. Lubomír Koutný
Borel (Built by and...
Borel (Built by and...
Borel (Built by and...
