A FRIENDLY FAMILY OF ULTRALIGHT MOTOR GLIDERS

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The Project

As it is possible to understand from the HOME page, this site is not concerning to an aeronautics company, but it is a personal site, born for hobby, only for passion.

The first idea was to design, to buid and to fly a little one seat ULM motorglider, for personal use, very safe in the fly, simple in the construction and easy to pilot; it must had flight characteristics and comfort higher compared to the various ultralight tubes and fabrics at that moment on the market (we were at the end of the 80s).

In the next years some other ULM motorglider was planned, more 'refined and with improved flight characteristics even better, always achievable only by construction plans, because the supply of kits or finished aircraft was not within the intent of the author; but let's order.

The first flights of the Piuma Original date back to 1990; compared to the prototype project and 'been improved in many aspects, and the plants have been amended several times.
Following further changes and refinements have led to the creation of the "Piuma Evolution", motor glider more high performance and comfort and its touring version fast "Piuma Tourer" with the wings of different profile and size.

A Piuma Tourer builder, confirmed the suitability of the name, by flying from Venice to Sicily one year (more than 1250 km) and from Venice to Paris another year (more than 900 km), confirming that even with small motor gliders are I can do great trips. A lot of Piuma are still under construction, while others are already been completed in Italy and abroad (look the builders gallery); the positive reactions of the builders have been a source of great satisfaction.

The Italian C.A.P. (E.A.A. Chapter 459) gave two prizes for the best ultralight project and the best achievement during the Carpi meeting of 1997 (prize "Giancarlo Maestri") and 1999 "(Caproni Cup").

Some two-seater versions have also been designed and drawn: the Piuma Twin then replaced by the Piuma Twin Evolution, that incorporates all the improvements suggested during 9 years of Piuma Twin construction; a 20 cm longer front fuselage, for better balance without ballast and a rear fuselage similar to the single seat Piuma Evolution.

Even the elevators cross follow the approach of the one seat Piuma Evolution; this form allows you to lighten up the tail to the benefit of ease of centering without ballast; more detailed information on the Piuma Twin Evolution pages.

A new project of two-seater Piuma Almerico with wings profile more similar to a glider and higher elongation wings was completed at the end of 2012: the author started its construction but then suspended its construction after a few years, introducing changes to make it a single-seater (more suited to the author's needs) modifying and replacing some parts already built of the two-seater (parts available if interested in some builders); the motorglider is almost completed at the end of 2020.


Neither completed motorgliders or kits are available. Together with the drawings, which show the Triptych and all the details to be built, a Construction Book is provided with instructions and references to the drawings, as will be explained in more detail in the pages relating to each model. There is also a note of all the materials to be purchased which specifies the quantity and quality of each necessary element, from the aviation birch plywood to the strips, to the aluminum alloy parts, to the Dacron fabric, glues, etc.

All the "Piuma" versions are designed in accordance with the best aeronautical standards and for each “Piuma” the Project Book is provided which contains:
  1. The design considerations for the shapes (wings, fin, rudder and elevators, fuselage with the rear engine mounting, etc.), with a lot of drawings of the fuselage, wings, tail, etc.
  2. Structural calculations.
  3. Flying characteristics of the wing, total drag, wing lift, efficiency, Vx, Vy, VNE, Vstall, etc.
This "Project Book" is not necessary for the normal builder, but it is very important for those who want to know the project better.

The construction

Some details require the use of a lathe and/or milling machine, but most of the construction may be built without special tools, It is very easy. The designer completed the Piuma Original after 18 months of work, in a 2 car garage, 21 feet long and 13.2 feet wide.

The construction time depends on the builder's meticulousness. Normally, about 1000 hours are sufficient for a person with limited woodworking experience to complete the work.

The materials and the plans

The plans are composed of large technical sheets (24 x 40 inches) with lots of details.

The ribs for the wings, fin, rudder and elevators are drawn full size. The same scale is used for many of the wood or aluminum parts. The handbook describes the work, step by step, and the pre-flight check list has 15 instructions up through take-off.

The materials are easily available as the usual ones used for the construction of planes in wood and fabric; in Europe the tail boom tube can be provided by the author.

Assembly and disassembly are quick (about 30 minutes for one person); a normal hang glider trailer, modified to support the wings, is good for transporting the Piuma.

Bibliography

  • L'ALIANTE - Dott. Ing. Stelio Frati
  • CALCOLI DI STRUTTURE AERONAUTICHE - Dott. Ing. Michelangelo Flaccavento
  • COSTRUZIONI AERONAUTICHE - Dott. Ing. Mario Ribaldone
  • AERODINAMICA PRATICA - Dott. Ing. Michelangelo Flaccavento
  • PRONTUARIO PER IL CALCOLO DI ELEMENTI STRUTTURALI - Diagio Furioni - Claudio Messina - Leonardo Paolini
  • THEORY OF WING SECTIONS - Ira H. Abbot - Albert E. Von Doenhoff
  • HANDBOOK OF AIRFOIL SECTIONS FOR LIGHT AIRCRAFT - M.S. Rice
  • Profili 2 Pro - Stefano Duranti - great software for wing profiles
  • Some magazines EXPERIMENTER and SPORT AVIATION of the EAA (USA)

Images