Roger JUNQUA's research and ultimate choice were guided by low fuel consumption and low construction coast. As the fuel consumption was becoming an increasing important factor of operating cost, it was necessary to look to a low-powered aircraft, while also striving to develop a plane that was reasonably fast, in order to reduce even further the kilometre/passenger cost ratio.
Two criteria which are not easy to merge!
But, by adopting the "canard" formula, Roger JUNQUA was able to obtain the considerable gains following:

• "given equivalent weight and power, a classical aircraft maximum speed is equal to a canard cruising speed, which means in effect that, at equivalent speeds, the power requirements of a canard aircraft is only three quarters that of a classical aircraft.
  
  Therefore a 55 hp engine would appear the adequate minimum at sea level (approximately 700 t/mn 180 km/h (97 Kts - 111 MPH) at two-thirds power). A 65 hp is more suitable for this aircraft, but 80 hp overpowered, as it would cause excess fuel consumption.
   

• The fuel consumption of this aircraft would thus be
   

  • 13 l/h (3.4 USG) at 200 km/h (110 Kts) i.e. 6.4 litres (1.7 USG) per 100 kms (54 nms - 62 miles)
     

  • 10.7 l/h (2.8 USG) at 185 km/h (100 Kts) i.e. 5.8 litres per 100 kms (54 nms - 62 miles) in economic conditions (28 hp).

  The range provided by this configuration is more than 900 km (486 NMS - 560 SM), at a cost three times lower than that of second-class rail travel, not including depreciation.
   

• To obtain such results it was necessary:

Roger JUNQUA was not anti-plastics, metals, fabrics nor for that matter "anti-progress", respecting all points of view. Thought it may be wrong to believe that wood, that most noble material, will be used in home building for a long time to come, it was still Rogers JUNQUA's opinion after 50 years of experience in aviation. Despite what critics say, its durability has been proven beyond doubt: an old wooden aircraft "Aiglon" built in 1936 using the glues of that era is still flying in 1999, 63 years later.

Moreover, most amateurs are capable of working with wood more than with any other material, and it is obviously easier to find an expert in wood should there be some tricks of the trade unknown of the amateur builder.

Because of its simplicity, the construction of the IBIS requires only a minimum of skill. However, the designers strongly recommend to follow the sequence of work set out in the 150 pages construction guide, as well as the tricks to be learnt and the snags to be avoided.