BZ-309 and 310

[Skybolt]

As promised, the only known (to me) drawing of these late Zappata's projects for Breda. BZ-309 is from 1947 and was an 11-passenger transport powered by two Isotta Fraschini Gamma (!!!). Data: span: 20.00 m; lenght 14.75 m; wing area 36.70 sq/m; empty weight 3,650 Kg; MTOW 5,500 Kg; max speed 400 Km/h; cruise speed 350 Km/h, ceiling: 7,000 m.
The BZ-310 was a partial derivative from 1948 using a mid-low wing with a pusher configuration, designed for being built on license in Argentina. The switch to pusher propellers was dictated by the use of an Argentina-built engine, the Istituto Aereotecnico de Cordoba "El Indio", with a power of 625 Hp. The El Indio engine had a high RPM and didn't use a reduction gear: this forbade using large diameter propellers, but using tractor propellers of a diameter such as not exceeding the critical Mach numer at the tips would have produced a very low efficiency use of the power. Moreover, El Indio had a large front section, compounding the tractor configuration problems. As a pusher, the BZ-310 could carry 12 passenger at a cruise speed of 300 Km/h at 2,100 m, with a range exceeding 1,000 Km.
The BZ-310 had itself a derivative, the 310A, using two Ranger SGV 770 D-1. All three projects used tricycle landing gears.

 

[Maveric]

Great find Skybolt, many thanks for this beautiful plane ;D

 

[airman]

They cannot missed : thanks !

 

[Hawker Nut]

Thanks Skybolt! The aircraft was very elegant. It could have filled a niche for itself in the early post-war era, despite the availability of war surplus at cheap prices.

 

[Skybolt]

Probably, but the Gamma powerplant was completely obsolete, and Isotta Fraschini was closing down, so there would have been a problem with spare parts. A Ranger powerplant would hve been much better.