|
Kyle,
In reply to a question you asked several postings back ... No, I no longer have the JPI-760. From your last posting it looks like you can see one of the benefits of using a pair of singles (RPM).
Referring back to a question previously in this thread (hard to believe there's even a debate on this):
The fact Cessna did or did not install a piece of equipment in their aircraft is hardly the basis for determining whether a device is useful or not. The fact the EGT gage was optional should illustrate this point. The single alternator & vacuum configurations are not evidence that redundant systems aren’t needed.
Engine monitors give you a much better view of what's happening in an engine. The digital read-outs let you see trends that are too small to notice on the analog gages. Shock cooling (as a rate of degrees per minute) can be displayed. And, there are alarms that can be programmed when numbers get out of range.
Regarding leaning, let’s say your target is 125 Degrees ROP. By observing the one cylinder that has the Cessna EGT (assuming you have that option installed), you have no clue as to whether the remaining cylinders are closer or further away from peak. It has been clearly demonstrated that the fuel flows at which each cylinder peaks can vary by a couple of gals/hour. You might think you’re running 125 dROP when in reality one of your cylinders could be at peak. Further compound this by having a blocked injector and you’ll unknowingly be running a cylinder LOP (pretty scared for the “non-believers” <grin>). It’s simply not possible to know how you’re leaning these engines without the proper instrumentation.
The Advanced Pilot Seminars shows some very interesting pictures of JPIs that help you interpret some of the monitor numbers. For instance, how can you tell a blocked injector from the beginnings of preignition (which is how you're going to burn a hole in a cylinder). What fluctuating numbers indicate which cylinders have exhaust valve wear?
I personally saw a situation, in which the plane felt fine, but the CHTs were hotter than normal - yet the EGTs were cooler. In my case the shop had set the ignition timing incorrectly. I would not have been able to see this without the monitor (and have prior use to recognize "normal" readings for this installation).
|