Queen sac: immortal or insane?

For black

Sacrifices are pretty normal in chess.

Here's an example

I'm afraid your Q sac loses against all reasonable moves and white has quite a choice but the best move is just to support the R with the N.

loses against all reasonable moves ? White is a clear winner in this position being up 5 points of material , 2 pieces for 1 pawn (6-1 = 5) . Also , black cannot move a single piece into white territory without capture .

Minor correction to post#25 it is 2 pawns and 1 piece meaning 3+2 = 5 material advantage

In the starting position, black is down a piece and is hopelessly lost. The queen sac is of debatable value (the engine does not love it very much), but it's good enough.

The line that you gave is very suspicious though. After 1. Qxa6 bxa6 2. b7, black's best defense is Rb8. White is still winning, that b6 pawn is a monster and all black's pieces are extremely bad.

line ... gave is very suspicious ? care to elaborate ?

Also , I kind of wish this did actually happen . Sadly, after 3.b8=Q computer replied with 3.Qxb8 trading queens but then after 4.Rxb8+ blundered 4.Kf7?? and fell into 5.Ng5+ winning a rook for free as 5+3-3=5

Also , is this an immortal or insane queen sacrifice ?

In the line you gave, black plays 2. b7 Ra7 (??) and lets the pawn queen. Isn't that insane? Black should play Rb8, blocking the pawn, and white has to work a bit.

Rb8?? Bxb8 Qxb8 Bxa6 .... Bd3 a6 and then black is facing a double rook double pawn pawn storm with guaranteed loss of material in devastating amount possibly 2 queens . That is worse then Ra7 where there is a line b8=Q Nc8 d5 cxd5 Nxd5 exd5 e6 Bxe6 Re1 Rhb7 Rxe6+ Kf7 Ng5+ Kg7 Be5+ Kh6 Bxf5 Rg7 Qxa7 Nxa7 Rxg6+ Rxg6 Nf7+ Kh7 Nxd8 Kh6 Nf7+ Kh7 Nh8 Kh6 Nxg6 where an apocalypse has decended on blacks queenside and kingside but white is far from delivering any immediate checkmates . Black is down 2 minor pieces , 1 rook and 2 pawns meaning 6+5+2 = 13 points of material .