Cape air studies replacement for 402's
05-07-2009, 06:36 AM
#62
Line Holder
Joined APC: Oct 2008
Posts: 44
Originally Posted by BoilerUP
Turbine TBO is based on hours...at least in the engines I'm familiar with.
05-07-2009, 06:48 AM
#63
Flying Farmer
Joined APC: Jul 2006
Position: Turbo-props' and John Deere's
Posts: 3,160
Originally Posted by 402Fanatic
Yeah I think everyone on here has rightly pointed out that acquisition cost will be a huge issue. Who knows though how much of a discount you'd get if you ordered 50 of anything.
Pardon me for being ignorant on this issue, but why would short flights be brutal on a turboprop. Isn't that what the Caravan was designed for and handles these hops pretty well? I've never worked around a Caravan so I don't have any idea. I know the fuel burn would be on average more for short hops. But I figured they'd be more reliable in any operating circumstance than a piston.
Pardon me for being ignorant on this issue, but why would short flights be brutal on a turboprop. Isn't that what the Caravan was designed for and handles these hops pretty well? I've never worked around a Caravan so I don't have any idea. I know the fuel burn would be on average more for short hops. But I figured they'd be more reliable in any operating circumstance than a piston.
Example: TBM850 at 3000ft is burning 75gph, maybe 240ktas, at 27000, 57gph @ 310ktas.
05-07-2009, 07:52 AM
#64
Line Holder
Joined APC: Oct 2008
Posts: 44
Originally Posted by Ewfflyer
Low altitude flights, ie short trips, are hugely inefficient because turbines efficiency is at the mid to upper 20's in turboprops. The overhauls aren't as much on cycles as they are hours, but cycles are harder on the engines because typically some of the hottest temps on an engine are during start. It's more of an issue in the resale market. Cycles also mean more landings on an airframe, some aircraft are sensitive in this realm, but once again, not a standard issue on turboprops.
Example: TBM850 at 3000ft is burning 75gph, maybe 240ktas, at 27000, 57gph @ 310ktas.
Example: TBM850 at 3000ft is burning 75gph, maybe 240ktas, at 27000, 57gph @ 310ktas.
05-07-2009, 04:56 PM
#65
Gets Weekends Off
Joined APC: Jul 2007
Position: C402, on the side with the switches!
Posts: 433
Originally Posted by 402Fanatic
Yeah everything I've seen says turbines are overhauled by the hours flown. So I don't see how short trips would be killer on them compared to a piston. So I guess that's why I was confused with those who said turbines would be beat up more on short hops when Caravans do this stuff every day all around the world.
05-07-2009, 06:06 PM
#66
El Capitan
Joined APC: Feb 2007
Posts: 615
Originally Posted by Mitragorz
Huh... One of the guys at the company told me about the "cycle" deal. Oh well, guess he was mistaken. I didn't know one way or the other.
05-08-2009, 07:46 AM
#67
Line Holder
Joined APC: Dec 2008
Position: C172 Right Side
Posts: 93
As far as turbine effeciency, I fly on a Caravan alot and on the longer legs of about 2 hrs we go up to 15K, above that the engine power drops off. For the shorter legs of less then an hour usually 6-7K. The Van would work well with this lower altitude effeciency, plus its the Van, the Van is awesome!!!
05-08-2009, 10:25 AM
#68
Flying Farmer
Joined APC: Jul 2006
Position: Turbo-props' and John Deere's
Posts: 3,160
Just talked with our Service manager to confirm the Engine overhaul on the PT6. There are a few components that are limited to cycles, but we as a Mx facility do not mess with those. There are the 1800hr hot section, and 3600hr Overhaul intervals, but that's really it. As long as an operator keeps track of the cycle logs, it would be beneficiary towards the long-term Mx of those engines.
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