Climb rate depends on weight, power, excess thrust, altitude, starting E....
More often than not you'd stall out.
There's no reason to base it off of climb rate. Ever. Best climb rate will be at a specific speed, regardless of other considerations. Your best bet to outclimb anything will be to zoom then go into best climb rate speed once you slow down.
Take a look at the climb rate next time you engage auto climb.. It's NOT a constant. It spikes and jumps and dips.
Plus if you're in combat don't use auto pilot! You are trying to out climb somebody? Use your human input device to make your plane do just that.
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