SIAI Marchetti SV.20


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22 January 2006
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I found this drawing on an advertisement published on Aviation Magazine International Number 516 15-June-1969 (the same issue where I found the Mirage Mach 3 :))

There is no other info but the drawing. Please could you give more info about this unbuilt project?

Thanks in advance


  • SV 20.jpg
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Dear Pometablava,

the SIAI SV.20 was twin engined high speed compound helicopter,
and all information about it in;'SIAI%20SV.20%20helicopter'
The construction of the SV.20 prototype was begun in 1968, but was never
completed and the project was cancelled in 1972.
The two PT6C-30 engines were located in nacelles on the stub wings, the right
engine additionally driving a pusher prop.
Maximum speed was expected as 390 km/h, maximum payload 2050 kg.


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Hesham and Jemiba,

thanks a lot for the info ;)

The pdf from is great and Boxkite is one of the co-authors

there was two projects,the SV.20A as a normal helicopter
with wing and the SV.20C a compound helicopter as my
dear Jemiba explained.


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  • SV.20C.JPG
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Confirm. The SV-20 was completend in mock-up form and was almost completed as a protortype when Agusta "bought" SIAI and the work was immediately stopped and the unfinished proto broken up. Guess why ? There are still VERY bad feelings between former employees on the matter.
Re: SIAI-Marchetti SV-20 helicopter project......

Dear Boys and Girls, here are two images with captions in French of the SIAI-Marchetti SV-20 helicopter project which isn't "secret". Both images come from 1969 issues of Aviation Magazine International......

The first image shows a model of the standard helicopter version of the SV-20......

The second image shows the compound helicopter version of the SV-20 with a pusher propellor on the starboard engine nacelle......

Terry (Caravellarella)


  • SIAI-Marchetti SV-20 helicopter project - Aviation Magazine International - No.jpg
    SIAI-Marchetti SV-20 helicopter project - Aviation Magazine International - No.jpg
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  • SIAI-Marchetti SV-20 compound helicopter project - Aviation Magazine International - No.jpg
    SIAI-Marchetti SV-20 compound helicopter project - Aviation Magazine International - No.jpg
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Another photo


  • siaimarchettis210sv20 (1).jpg
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Probably from the same event as the photo above, a poor scan of the SV.20A mock-up at the 1971 Paris Air Salon.

Flight notes for the proposed SV.20CH:

An almost conventional 12-seat helicopter with two PT6s mounted on
stub wings, the aircraft should be transformed into a compound helicopter
—the SV20CH—by 1974. A start on the first variant with a range of 350
n.m., 650km should be made within a year and selling price will be about
$0.5 million.

The twin-bladed semi-rigid teetering rotor has a span of 42ft. Maximum
take-off weight is around the 8,8201b, 4,000kg mark allowing a payload of
2,0371b, 924kg.

The compound helicopter will use the port PT6 to drive the rotor while the second
will drive a pusher propeller.


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