RPM Gauge’s which one…

Little quandary about which RPM Gauges the Whirlwind had installed, there’s a choice of two.

At first we had thought it was an easy win for a Mk. IVA rated at 3500rpm max.

This unit was chosen after looking through all the operational limits for the Peregrine as they were 3000rpm max and under…

Good that was easy, but then after looking a little deeper I found this…

As you can see for a maximum dive the engine rpm is rated at 3600, but this is for a “momentary” amount of time and I should think this was only used in an extreme emergency and if this was done the incident must be logged…

Now, would this be OK using the Mk. IVA (Max 3500rpm) or would it mean that the Mk. IVB rated at 5000rpm would be chosen over the Mk. IVA for just that type of emergency… :confused:

Of course if we could see the bloody gauge I wouldn’t be asking, but as yet we only have the P’s N’s cockpit images to go on, which means gauge limits are un-discernible and the type are not listed in the Spare Parts Manual or the AP’s…

Your help Gentlemen would be greatly appreciated…