instantaneous VSI
i don't work in aviation but am facinated by it. recently i obtained an instantaneous VSI as a souvenier. it was formerly from a B747. While i think i understand how an ordinary VSI works , how does an "instantaneous" one differ mechanically? I have heard that it has accelerometers ? is that true ...The unit i have is from aerosonic i think. the unit i have has a port for the static . it also has a three pin power socket. does the "instant " function need power ..or is it a pure mechanical thing. furthermore , the needle seems to indicate a 250 feet climb at rest and there is no zero correction knob ..why is this so ? is my instrument defective (i.e those in operation never have an zero error ?)why isn't there a zero error knob ?
a lot of questions ...sorry !