Flight, December 1926

The Paris Aero Show 1926

FIAT

   THROUGH a misunderstanding the Fiat single-seater fighter was not included in our advance report of December 2 dealing with the machines exhibited at Paris. It is, therefore, intended to describe it at rather more detail than we have been able to devote to the majority of machines in the present issue.
   The Fiat type C.R.20, with 410 h.p. Fiat A-20 engine, is a single-seater fighter of all-metal construction. In its general lines it is of orthodox design, with the possible exception of the somewhat unusual nose radiator (shaped to conform roughly to the V of the engine cylinder banks), and the wing bracing, which is in the form of a Warren truss, no wires at all being employed. One of our photographs this week illustrates the general appearance of the machine. The Fiat, incidentally, was exhibited in what is probably the best manner possible, i.e., one side stripped to the centre line and the other side covered. This is probably a fairly expensive way of preparing a machine for exhibition, but it is undoubtedly a very excellent one. From one side all the detail construction can be inspected, while from the other one may form an idea of the "lines" of the machine. It may be recollected that during the war it was the custom at the Agricultural Hall, Islington, where captured enemy aircraft were exhibited, to strip the machines to the centre line in this fashion.
   The construction of the Fiat C.R.20 is of considerable interest, since the form chosen obviously represents an attempt at simplicity coupled with the use of an all-metal structure. The wings have built-up steel spars, each spar being in two halves, and the overlaps of these halves riveted on the top and bottom centre lines of the spar. The construction, which is probably reasonably cheap, is illustrated by one of our sketches. It would appear doubtful whether with the shallow curvature of the top and bottom spar faces the full strength of the material can be developed before the spar buckles in compression. As a production job, however, there is much to be said for the Fiat spar. The wing ribs are built up from square-section tubes.
   The fuselage is of tubular construction as regards its main members, steel being the material used. The secondary structure, however, which is of duralumin, appears to be so intermixed with the main structure that it is difficult to say where one ends and the other begins. The result is that curved formers supporting longitudinal stringers are used at the same time as steadying struts in the fuselage structure. The utility as a strut of a member that is thus initially curved may be questioned. The "bays" in the fuselage are very long (the struts are triangulated in the form of a Warren girder), and the bent formers meet the longerons midway between main strut attachments.
   Following is a brief specification of the Fiat C.R.20 :- Length o.a., 6-7 m. (22 ft.); span, 9-8 m. (32 ft 2 ins.); wing area, 25-85 sq. m. (278 sq. ft.); weight of machine empty, 940 kg. (2,070 lbs.); petrol, oil, crew, and military equipment, 420 kg. (925 lbs.). Total loaded weight, 1,360 kg. (3,000 lb.); wing loading, 52-5 kg./sq. m. (10-8 lb./sq. ft.); power loading, 3-24 kg./h.p. (7-13 lb./h.p.); "wing power," 15-8 h.p./sq. m. (1-5 h.p./sq. ft.); theoretical ceiling, 9,000 m. (29,500 ft.); service ceiling, 8,500 m. (27,900 ft.); endurance, 2 1/2 hours at full throttle; speed at ground level, 276 km./hr. (171 m.p.h.); speed at 3,000 m. (9,850 ft.), 264 km./hr. (164 m.p.h.); speed at 6,000 m. (19,700 ft.), 240 km./hr. (149 m.p.h.); climb to 3,000 m. in 6 mins. 41 secs.; to 6,000 m. in 16 mins. 58 secs.

Flight, June 1929

OLYMPIA AERO SHOW 1929

The Fiat C.R.20

   On the Italian stand in the annexe is also exhibited an Italian service machine, the Fiat C.R.20, fitted with 450 h.p. Fiat engine. This machine, although of Fiat design, was, we understand, constructed by the Macchi factories. Certainly the very beautifully-made wooden floats were made by that firm. The machine, concerning which, unfortunately, but little information can be obtained, is a single-seater fighter, of all-metal construction with the exception of the floats, and is unusual in that it has rigid wing bracing in the form of a Warren girder. The floats bear strong evidence of Schneider Trophy influence in their design, and indicate how racing has, in this instance, taught the constructors something which can be applied to a service type of machine. The Fiat C.K.20 shows the usual broad and flat nose radiator which one associates with the machines of this firm, and is very like a machine exhibited at one of the Paris Aero Shows, when, however, the fighter exhibited was a landplane.