Model Variations

[j79guy]

Model variations amongst PT6
Again, not definitive, but a good start.

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PT6%20Pg5.jpg

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PT6%20Pg4.jpg

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Pt6%20Pg3.jpg

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PT6%20Pg2.jpg

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PT6%20Pg1.jpg

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PT6%20Pratt%20and%20Whitney.jpg

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[TillamookTurbine]

You Canadian guys can probably confirm or disabuse us of some of the urban myths in the pilot community that I've heard about the PT-6.

Every year for 11 I attended Flight Safety International (FSI) on the CE208. The instructors, to illustrate the deterioration from starts, would dutifully recite the story that there are PT6's running in the Canadian wilds pumping gas that have been operation for 30 years without being shutdown. Pilots, not being engineers, would dutifully ooh and ahh ignoring the fact that would be about 250,000 hours of operation.

Another from FSI was that the RCMP was flying a 208 and the speeder opposing spring broke in the FCU so the engine oversped and was saved from exploding by the OS governor. The pilots were over mountains so they would climb while the engine was overspeeding and then shut down and glide. This cycle, supposedly, was repeated several times.

These are great stories with a probably some truth but I expect that there are some parts that have been left out.

[j79guy]

Hmmmmm, no PT6 based gas pumpers that I know of, too small. Generally, if 2000 shaft horsepower or greater is required, you will see a turbine. Or, if power density is a requirement, you will see down to 1000 Shp, in the Solar Saturn range. P&W did make a twin Pack, where two PT6's were joined together on a common reduction gearbox, for electric generation. I think it was called ST-18 (?)
Industrial turbines, at least the older more reliable ones, would run 10,000 fired hours between combustor changes, and 30,000 fired hours between major overhauls. The newer aeroderivitives are averaging 17,000 fired hours between major overhauls. To put in persepective, that is like putting the throttles of an F4 Phantom at 95% and holding it there for 3.5 years. Impressive yes, but not really that unusual, with the good maintenance and clean fuel that industrial units get. Plus contrary to popular belief, industrial aeroderivitive turbines are built to a tighter standard than flight engines, in terms of oil leakage, vibration limits and gas path clearances.

Robin.

[TillamookTurbine]

Robin:

Thanks for another informativ post. The PT6 photos did not come through but I can open all your othe photos with no problem; including your fine WestJet photo.

Terry

[TillamookTurbine]

Robin:

Sorry, the jpg's did come through. I was looking for photos of engines but now realize that it's the model variation charts that are the jpg's.

Terry