GP1 Glider
GP1 Glider Overview
The GP1 is a radio-controlled scale model glider featuring a wingspan of 178 cm, inspired by an Italian glider from 1925. This model is designed for ease of construction and reliable performance, making it an excellent choice for newcomers to the fascinating world of gliding.
I've always appreciated smaller gliders due to their require less effort in terms of both building and transportation, making them easier to store. Although their flight experience may not match the grandeur of larger models, they offer a refreshing change of pace. The inspiration for the GP1 came after discovering its history in the book 'Vintage Italian Gliders.'
Historical Significance
In 1926, the GP1 set a world distance record, launching from the Campo dei Fiori in Varese. Its wing design featured three sections: the central portion was flat and without dihedral, while the tips were raised and tapered. The wing structure consisted of wood, and the covering was crafted from fabric, including the ailerons.
As was typical for gliders of the era, it did not include an aerodynamic braking system. The fuselage comprised frames connected by four stringers, and the covering was made from plywood. A shock-absorbing skid was installed at the front-lower section of the fuselage. The empennage featured rounded tips and followed the classic design, also covered in fabric.
The 1:10 scale model has a wingspan of 178 cm, with a wing root chord of 16 cm and a tip chord of 11.5 cm. It has an estimated weight of approximately 400 grams and a surface area of 25 dm², resulting in a low wing loading of 16 g/dm².
Design Features
The wing profile is based on the classic Clark Y, which is not only easy to build but also well-suited for the model's intended characteristics. To simplify construction—and though it may slightly affect the model's appearance—we designed a two-part wing with basic dihedral. The original design called for a three-part wing consisting of a flat central wing and two outer wings with a gentle dihedral. For those interested, adapting the design for a more detailed scale reproduction is certainly feasible; however, our primary aim was to create a recreational model that closely resembles the original.
Tail Assembly
Starting with the empennage, the main spars of the stabilizer joint are made from 2x8 mm balsa, glued together sideways to form a T-profile. A 2 mm strip is temporarily glued between the fixed and movable parts to serve as a spacer; this will later be removed after sanding the stabilizer.
The trailing edges of gliders and airplanes from that era were often constructed from steel cables, which would curve under the tension of the covering, creating a classic 'batwing' effect. To achieve this effect, we opted for Kevlar wire instead of steel to avoid the stiffness and weight that would come from using metal at this scale. The Kevlar is inserted into slots and secured with cyanoacrylate glue, leaving a little slack between each rib to allow the covering to stretch adequately. The wingtips are made from 2 mm wicker or bamboo, further complementing the model's authentic design.
