Porco Rosso,
Just to add to 411as good post. The PT6A-20s and the PT6A- 27 s and 28s ,are somewhat different engines, but only slightly.
The -20 the first one fitted to DHC-6-100/200 and B90 s have a tendancey to be temp limited especially in Tropical climates. They also start hotter due to of a single stage fuel nozzles. And because of this their life is shorter, especially without Trend monitoring carried out. Be sure you boss gets Trend Monitoring, put in place, as it will save him litterally tens of thousands of US dollars. An extension from 3500hrs to 5000hrs is alot of money and time saved. Something they dont even do where I am, but thats another story....
The -27S AND -28S on the other hand arent as limited. That means you should still use a Torque meter and computer to work out T/O settings especially in hot regions. The -27S have dual stage fuel nozzeles 7 primary amd 7 secondary ( out of the DHC-6-300 Manual). So in effect there is a staggered light off you get 2 peaks one at around 20-26% ng or n1 and the second light off at around 35% to 40%ng or n1.( this reduces the start temp compared to the older -20, hence I think the reason for the mod) On on a -27 or 28 , you dont release the starter until the 52% and the Ng is self sustaining.
Turbine life is inversally proportional to the number of warm starts or temp limit breaches.
Just for handling the engine. The main care I like to see, is advance the powerlevers gently until around 60%ng or n1 or greater after which there shouldnt be a problem moving them faster from there on. Otherwise youll dump in too much fuel too early and breach a limit. Also reduces engine life. Where I am at the moment alot of F/Os are handling them like a recip, you cant really.
Now in saying that ,allways ensure you have the correct Voltage available and a good GPU. Otherwise you could breach a limit.
The Pratt site mentioned above is good reading also.
Regards
Sheep
I think though from the -27 onwards I think they are a very robust engine. Treat it like you would your mother, and it will give you back the same.
Your question as to what are -34S LIKE , not sure myself. But I know they are fitted to EMB-110 Banderante. So any Bandit Pilots out there can add info on the -34?
To add to what another person has, said ensure that its on your UK CAA Approval list of Types, as they have banned some Turbo Props, not sure why.