About this Plan
Paragon. Free flight sport model, uses wing slots.
Quote: "The Paragon takes wing. It looks like a real plane and flies like a contest model. A slotted wing gives superior efficiency and stability. Paragon, by Frank Ehling.
Here, for the first time, is a gas job that employs the use of wing slots to obtain the highest degree of wing efficiency and to increase stability.
Why use wing slots? That can be best answered by giving some advantages of wing slots; those used on this model were designed by your editor Mr CH Grant. This is the ideal wing section for the beginner, for while we do not claim this wing section to out-climb any others, it will certainly out-glide the rest. This is accounted for as the wing slot, when used correctly, will increase the efficiency of the wing section greatly and produce the extra lift desired by the builder who wants top notch performance.
The stability gained by using slots is not to be overlooked as this ship was flown many time and then a change was made to shift the weights backwards. To our surprise the ship's performance was almost doubled. To check this, the slot was closed with the use of Scotch tape and again flown; then the ship that was as stable as an ocean-going liner was turned in to a tricky little hard-to-fly ship. This was the final proof of our experiments. The wing slots also offer the designer the use of a shorter tail moment arm; this will be appreciated by the flier who wants his ship to recover as soon as the motor cuts. Also the ship soars more easily than one with a long tail moment arm.
When this model was designed, no thought of contest work was in mind; however, since completion it has proved to be a potential contest ship. This along with the appearance of a real plane has won the hearts of all who have seen it.
It has had over fifty flights though taken to the field on only three different occasions. The Paragon has lived up to it name, in more ways than one: It is as stable as a giant clipper, with the zest of a pursuit ship, and a glide that can be compared with an underweight model, proving the effect that slots have on model airplanes.
Powered with the new Bantam it makes an excellent class A job and it can also be flown with any class B engine as long as the total weight does not exceed twenty two ounces to obtain the highest efficiency.
Wing: Start the wing by enlarging thewing plan four times the size shown. The wing slots are built first. This is done in the following manner: cut the ribs that are needed, the spar, leading and trailing edges and assemble these as you would build a regular wing. Cover this panel with 1/32 sheet and sand smooth. Then cover with tissue and dope. The rest of the wing proper is now built in the usual way.
Sheet the leading edge where the slot is with 1/32 sheet then cover with tissue and dope. Tips are carved from solid blocks. Now cover the whole wing with Silkspan and dope. When this is finished the two wing parts can be cemented in place to form the slot, making sure the opening is as shown on the plan. The two panels are joined together with the 1/8 sheet gussets and a dihedral as shown on the plan.
Stabilizer and Rudder: This construction is as simple as can be; all that is required is to draw the plan full size, then cut the parts from 3/16 sheet and cement in place. This structure, when dry, is sanded to a streamline shape. The rudder is built in the same manner. When finished both are covered with Silkspan. The fillets between the rudder and the stabilizer are then carved to conform with the fuselage and cemented in place.
Fuselage: The fuselage is of simple box construction with a few formers on top at the rear of the cabin. A plywood bulkhead serves as an excellent place to bolt on the forward landing gear, which is bent to sharp as shown on the plan, of 3/32 diameter music wire; the rear gear is bent to shape from 1/16 diameter wire. Solder the clamps in their proper place on the rear gear. The whole assembly is then bolted to the correct place on the plywood strips, which are cemented to the inside of the fuselage bottom.
The whole structure is covered with 1/16 soft balsa sheet; after this has been sanded smooth the whole body is then covered with tissue.
The ignition track is made in the following manner: Cut two formers from 1/8 birch plywood to the size shown. Cut the motor mounts from aluminum. Drill the required holes and bend to shape; they can now be bolted to the former. To the rear of the former the brass angle can be bolted; to this the tongue can be bolted, which is cut iron pine. The box to hold the battery, coil and timer is made of hard balsa and this is held to the tongue with rubber bands till the ship has been thoroughly tested then it can be cemented in place. The cowl is carved to shape, hollowed out to 1/4 in thickness and covered with silk and dope.
Silk can be used for the hinge. Cut out for the exhaust opening: this will be determined by the individual engine that the builder uses.
The windows are now covered with a good grade of celluloid or something that will not wrinkle when it gets a little damp. The center part of the wing should also be covered with celluloid, as this is very helpful when you want to see inside the body without removing the wing.
Flying: Glide the ship till the glide is as flat and prolonged as possible. This will take a little time as this ship can be tail-heavy and still give a fair account of itself; this can be credited to the use of slots. After a satisfactory glide is obtained the ship may be flown; give it a ten-second run and watch how it acts.
It may be said that it will not be necessary to fly the ship in tight circles as it has not looped yet. We hope you get as much fun from this ship as we did. We would like to hear from all who build it and will answer any questions that may arise; just send a stamped, self-addressed envelope to the author, care of Model Airplane News. Happy landings!"
Update 04/12/2018: Added PDFvector plan tracing, thanks to hogal.
Supplementary file notes
Article, thanks to Newtmagick.
PDFvector plan tracing.
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