Plagiarist (oz10771)

About this Plan

Plagiarist. Free flight power model. For K&B .29 engine.

Quote: "Class B Free Flight winner that completely spells out the parameters of design plus those areas from which the designer copied the best features of the competition! A factually honest report that tells all with the added plus of making the combinations a winner. Plagiarist, by John C Warren.

The Plagiarist was designed to be a high-performance competition model. I have been flying a Texan '832' (oz2964) with a K&B .29 for several years. The Texan had a good glide but did not have the speed in climb necessary to obtain a highly competitive altitude. It was always a bridesmaid; seldom a bride.

The main objective in designing the Plagiarist was to increase climbing speed without sacrificing glide. In searching for a design which would satisfy my criteria, I found that most proven designs had certain features which were good. I decided to put these features together into one airplane which would give me a top notch Class B competition model - 'The Plagiarist'.

The elliptical shapes are influenced by Bob Cherney's Orbiteer. The wing and stab construction are also similar to the Orbiteer. These construction methods have proven themselves in the rigors of FAI competition. The additional work of an elliptical geodetic structure is well worth the effort. The efficiency, beauty and warp-free qualities speak for themselves.

At the 1969 Phoenix South-western Regionals, the model sat out a rain and hail storm in a model box left on the field. This occured between the first and second flights. The power pattern in each flight was identical.

The basic moments are from the '832' Texan. Dihedral angles are, of course, Texan for ease in packing into a model box. (I still use Texans in Class A and Class C). To increase speed in the Plagiarist, I reduced the wing area to 789 square inches flat. Stabilizer percentage was lowered from 50% to 40%. Wing incidence was reduced in order to obtain a straighter power pattern. The rudder size and shape were determined by trial, error and x-acto. It was necessary to remove three square inches of area on the original. The model was unforgiving with the larger rudder. Contest balsa should be used throughout, and the completed plane should weigh 30-34 oz.

In the construction of the elliptical tips I recommend using a laminated trailing edge in the stab, and sheet LE in the wing. The stab needs the additional strength. The wing TE can be done nicely with sheet balsa. The original was covered with Jap tissue. If you are covering with silk, laminated trailing edges should be used in both wing and stab.

Construction is begun with the stabilizer. Main stab ribs should be cut from light 3/32 sheet. I use heavy paper patterns for the main ribs and trace them on to the balsa sheet using a wide felt pen to obtain the outline. Half ribs are traced from the front section of the next larger main rib. The half ribs are then trimmed at the LE to fit. Geodetic ribs are 1/16 sheet. The geodetic is over size and must be trimmed to fit. First, lay up the leading edge, trailing edge and tips.

In making laminated leading and trailing edges, you will find it helpful to do as much shaping as possible before it is cemented into the structure. You can also preshape most of the sheet trailing edge for the wing tips. Notch TE and tips for ribs and spars. Place bottom spars and main ribs. Cement in top front spar, allowing it to bend over the curvature of the main ribs. Fit half ribs and geodetic ribs. In fitting the top rear spar, the geodetic ribs will have to be notched to spar depth. This depth is judged by using the main ribs as a guide.

Add 1/16 sheeting, indicated webbing between spars and gussets. The ribs in sheeted areas are relieved to take the 1/16 planking. You now have a perfect stabilizer. All that remains for you to do is remove the excess balsa which lies outside the air foil shape. Care in the next step is essential..."

Direct submission to Outerzone.

Update 04/01/2019: Added article, thanks to RFJ.

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