Spot on correct. That’s the only known surviving airframe, in the Indian Air Force museum at Palam. Your turn!
Ok, I think we should start with something easy, so please identify this nice beastie:
http://img168.imageshack.us/img168/5059/poza5st5.jpg
If possible, try to guess the exact type and designation.
Good one, my dear Mr. Wingsofwrath. It seems to me that this bird is equipped with an Isotta-Fraschini Asso engine, therefore my first offer will be: Savoia-Marchetti SM-62. 
You my dear sir, are a connoisseur.
The airplane is indeed a Savoia-Marchetti SM-62, but for my own curiosity, can you please tell me: is this a straight SM62, or the upgraded version SM 62 Bis?
Thank you very much for your kind words, my dear Mr. Mr. Wingsofwrath! 
However, I am afraid that this little designation conundrum will remain unsettled. You see, the most significant, absolutely undisputable details connected with the SM 62 bis were its slightly bigger wingspan and somewhat different, more powerful engine. Those details are, unfortunately, unobservable from this angle, but…
As far as I know, that petite electric generator (yes, that cute little teardrop-streamlined thing, clearly visible at the upper wing - right above the larboard “N” upper wing pillar), was a distinctive feature of the SM 62 bis. Earlier variant of the airplane, SM 62, had that distinctive part above the opposite, starboard “N” pillar. The only problem is the fact that this characteristic was emblematic for the civilian variant, SM 62 P as well… 
It is indeed an SM 62 Bis, and the details that set it apart form the P variant are the presence of a bomb rack underneath the right wing and the partially enclosed tail gunner position visible just behind the engine. (not to mention the bunch of people all in Navy uniforms)
In any case, I await your riddle with the utmost interest.
Edit: Typo
Excellent, my dear Mr. Wingsofwrath!
The only problem in my previous speculation was a tiny actuality that 4 Bis machines actually represented converted P machines. But, after all I am glad that this little puzzle is resolved.
And now - something more exotic, my dear Mr. Wingsofwrath. As before, this time I am requesting the exact type and a full designation of this contraption:
And yes – it only looks as a completely civilian machine. Unbelievably, but this… apparatus actually was a multi-purpose airplane! 
Ugh, that’s a hard one. I admit I’ve never seen this… aircraft… before, and I spent half a day looking trough my books and other archives.
There are a lot of similar airplanes out there, but this exact one still eludes me for the moment.
Hopefully, the answer will reveal itself later.
Much later edit: For some reason, trough all my browsing, I come back to airplanes manufactured by the GENERAL AIRCRAFT LIMITED company.
I am now 97% sure that the mystery aircraft is comprised of a General Aircraft Monospar (probably ST-11/2) fuselage, with the wings from the same model mounted on top and the twin tail booms of the G.A.L 33 Cagnet. However, I can’t find a single written record of this extraordinary contraption, a fact which leads me to believe that probably it was one of a kind, or/and made by some other company. (or I could be dead wrong)
Inquiries on the subject will continue.
Undoubtedly, my dear Mr. Wingsofwrath - the answer surely will be revealed one day. In the meantime, as a tiny intellectual impetus, I will tell you that this unorthodox multi-role machine was introduced back there in 1936. In addition, it has absolutely nothing in common with the General Aircraft Monospar or G.A.L 33 Cagnet.
Keep up the good work!
Although it could be considered rather daring from my part, allow me to disagree, my dear Mr. Librarian. Even though you stated your mystery plane is in no way related with the General Aircraft Monospar, the engines are a highly distinctive type manufactured by the Pobjoy Airmotors corporation (be it “P”, “R”, Cascade or Niagara, the basic shape is the same). There is absolutely no doubt about that, and since both the yet unnamed contraption and the Monospar share the same type of engine, I’d say there is a connection between the two, albeit fortuitous…
But in any case, I want to make another offer: Is it possible that the object of this quiz is actually a highly modified Short Scion II airframe?
I know such an aircraft (G-ADDR - built in 1935) existed and was used by the Short corporation as a flying testbed for a variety of experiments, including wing tests for the Empire flying boats and experimental wing slats, but so far I have been unable to find any photos.
And in any case, from a visual standpoint, a Scion it would be a closer match to the mystery aircraft in terms of wings, fuselage and landing gear, although the tail itself is highly reminiscent of the “Hammond Y” in it’s design…
Hawkeyes, my dear Mr. Wingsofwrath! Indeed, our mystery machine was equipped with a pair of Pobjoy Niagara engines, but if the engine sharing is the most important connective component in your research, you will be able to bond our mystery machine with numerous other projects like the Cierva CL 20, Gwin Aircar, Light F 15, Feiro Dongó II… etc.
However, if truth is to be said, you got it just right – the Pobjoy Niagara is the only connecting element between “our” machine and all those previously mentioned types. Alas, as before, all those freshly offered solutions (a highly modified Short Scion II airframe, Hammond Y) are wrong. Our machine actually was a completely autochthon construction.
So please – keep on looking!
You are certainly a sly one, my dear Mr Librarian, but I have the answer to your riddle (it was the use of the word “autochthon” and the barely visible “YU” marking on the wing of the mystery photo that finally tipped me off :D):
Mitrović MMS-3, built by Aeroput in 1936 as a three seat multirole aircraft (could be used as a small passenger, mailplane, etc)
Man, you folks are GOOD.
Oh, you almost do have that required response, my dear Mr. Wingsofwrath. Otherwise you do have my sincerest congratulations – yes, this is the airplane in question, and yes – everything you have mentioned is completely connected with this machine, but… the exact brand name (you know – actually an item that distinctively marked the very start of our relationship here) is still missing.
But don’t worry - I will help you. The first “M” is for “monoplane”. The second one is an abbreviation for “Mitrović” (constructor’s name). But what on earth means that “S”? Very probably the name of the other constructor (actually this observation plane, light transporter, liaison machine and ambulance was a team-design, and it was offered to the RYAF in 1937 after its complete debacle as a commercial airplane. Unfortunately, it was refused yet again).
Otherwise, I think that this little contest we had here actually will be a remarkable continuance of the last line of the legendary film Casablanca:
http://www.youtube.com/watch?v=8vY-4zWKsJM
In the meantime, as always - all the best!
Tsk.
My dear Mr Librarian, I think you are trying to lead me down a wrong path by mentioning “another constructor”.
As far as I know it, there was only one designer, whose full name was Milenko Mitrović-Spirta (which would account for the “S”) that in 1934 worked as a technical director of Aeroput AD, Zemun, Belgrad,Yugoslavia.
Of the airplane in question there was only one built, originally as a fully civilian machine, and during the years 1936-39 it was used to ferry mail between Podujevo, Belgrade and Skopje, using the registration number “YU-SAR”.
On the 15th of September 1936 an engine failure led to a forced landing, but the machine was repaired in early 1937.
Although it was originally a tail dragger, in April 1940 it was added a front wheel (you can see it the picture I posted earlier) and served as a test basis for a hypothetical bomber version called NEMI, but the project never materialized.
In March 1941, in face of the German invasion, the aircraft was impressed into service with the JKRV (Yugoslav Air Force) and during that time it flew with the 603 Auxiliary Squadron as a liaison and observation machine.
According to eyewitnesses, after the fall of the country, this extraordinary machine was destroyed by its own crew to keep it from falling into German hands.
If you want, I can also provide you with full technical characteristics…
In any case, since I’m 100% this is as complete as it can be, allow me to return the favor by posting a small mystery of my own:
What is the full name of this machine?
I also hope this is just the start of a long and hopefully fruitful collaboration.
Oh, I’m never confusing my co-contestants, my dear Mr. Wingsofwrath. And I am also assuring you that all those already on-line available works about this airplane are slightly incomplete. The best on-line available is this one:
http://www.samoloty.ow.pl/str372.htm
However, they are not mentioning that an engineering team of “Aeroput” company actually designed that previously mentioned airplane. Nevertheless, I suppose that a prominent Hungarian aircraft historian Mr. Peter Zsille will be the first one to publish the whole story about that forgotten airplane. Well, we will wait for the official translation for a while…
And yes: Monoplan Mitrović-Spirta MMS 3 is the full designation of the airplane. Thank you.
BTW: are you sure that this one was - by hook or by crook! - connected with the WW2?
Yes, in the same way as the MMS-3.
As far as the latter is concerned, I had a hunch that there was more to the story than I could dig up, but as you said it, my sources (including the one you mentioned - and which by the way was a pretty difficult one, since I don’t speak Polish) were a little limited…
This is the Romanian RAS Getta No. 1!
Wow, that was quick!
You are absolutely right!
The first Romanian seaplane, it was built in by engineer Radu Stoica 1925 for the STC (Societatea deTransport Constanta - Constanta Transport Company) and a further 3 were ordered by the Ministry of Defence. Unfortunately, after the delivery, due to some shady business inside the ministry, any further orders were canceled, and Romania ended up buying Savoia 59’s instead…
In any case, by the time of WW2, the planes were severely obsolescent so they were relegated to use as school aircraft for Hydro pilots. They were scrapped sometimes after the war.
Thank you Wingsofwrath!
The next one is maybe a bit tricky, it wasn’t successful, but it was a star.
