[WWI] Brazilian Nieuport: 17, 21, 24, 28?

[Marcio Antonio Campos]

Folks,

I may have already asked this 4 years ago, but obviously the answer is
lost somewhere.

Brazil used some old Nieuports in the 20's, and one of them (I mean,
propeller, engine and tail - all the rest is a replica) is in our
Aviation Museum at Campo dos Affonsos, Rio de Janeiro (some of you
have already been there - I haven't).

Although this Nieuport is classified in the museum as a 21, it really
doesn't look like one. To me looks like a 17, but I'm not a Nieuport
expert so I request your help. Here go some pictures of the plane. The
first website has a walk-around:

http://www.ipmspoa.com.br/artigos/artigo24/index.php

http://www.trekearth.com/gallery/South_America/Brazil/photo831747.htm

Or could it be that we did have Nieuport 21's and the guys at the
museum did a wrong job?

All the best from Brazil

Marcio