@Nilgiri can you tell us some good stuff about this engine
The PT6? It is arguably the gold standard in its category (turboprop/turboshaft of this thrust or power rating).
I have some time to spare right now, so something larger to think about for all interested readers in thread:
What some may not know (that is unique to it and has influenced a huge amount of engines in its category) is that half of its initial design engineering was influenced not only by the basic performance/efficiency goals but also ease of maintenance + simplicity.
To really understand what makes the PT-6 (and all the later engines it has influenced) unique, one must understand this approach to simplicity + reliability as the priority in the whole larger system (rather than think only in conventional layout terms).
i.e to think in concept of Engine performance + Engine MRO rather than just the former.
This is why the (at that point novel) unorthodox layout inside (back to front) which provides:
A) Elegant answer to driving the prop from (free) power turbine, i.e much shorter+reliable shaft
B) Quick access to (esp on field) engine core by removing the prop + power turbine assembly for field maintenance. Lot less hours needed and saves money and downtime.
You can see A and B advantage in this video around 1 minute mark especially (a regular layout would mean you just cannot take power+prop so easily like this as they would be on different ends with long shaft connecting them that you need to account for):
From beginning to end in that video....doing exact same stuff would take way longer with a regular "front to back" layout turboprop....as prop + PT modularity is immense time saver.
It is even bigger timesaver if a quick inspection is all that is warranted....as its quick take A off B, look at B....put A back on etc.
There are cpl minor errors in this following video, but it does a good job (it is not field or hangar maintenance but rather full overhaul which takes much longer time, but it illustrates lot of similar pertinent points):
It is a somewhat lesser known side of an "engine" (people often think mostly of the upstream development and acquisition and use side only...i.e what is the "buying" price and fuel cost per hour etc) so I took this tangent this time to add something a bit different.....since knowing this side more gives fuller picture of all the decision making for a prospective buyer with an application requirement to make optimal call.
Given dearth of experience and heritage with PT6 now (and the way the family of its variants has grown from the original), there is immense MRO capacity for it that keeps the total cost (for any client) very low. This is why you see it in huge number of aircraft today.
Think of same thing with a mass produced good quality reliable automobile, nearly every garage will have parts for it given volume and ubiquity....saving you (the client) time and effort especially if you plan on using the car regularly and day to day. Same (larger cost) concept applies.
@VCheng @Anmdt et al.
