Skytrain, sorry for a bit unlucky (unwise?) wording in my post. What I meant is that some challenge pictures can be cracked purely by Google means without knowing any search terms nor where to look. I have promised not to play in WC if that is the case with the challenge. This one can be cracked without even knowing that it is an aircraft, so I refrain, except now that it had been up for four days and that I had read in the sources I had found that it is homebuilt.
I may play with the tools (available to everyone without any additional cost) in some other threads, but often wait until I see that the challenge is not cracked by others. This is just me personally, I am not proposing it to be adopted.
PS: the sentence I quoted in my post was from Wikipedia.