Page 1 of 1

Turboprop Efficiency At Long Distances

Posted: Mon Feb 28, 2011 1:44 am
by cloudboy
Turboprops tend to be more efficient at short distances over jets. Is there a point, however, where the advantage goes to the jet when you factor in speed and distance traveled? It would seem that for long flight distances the fact that a turboprop flies slower would mean that there is more fuel consumed as the plane is in the air much longer.

RE: Turboprop Efficiency At Long Distances

Posted: Mon Feb 28, 2011 2:31 am
by DesertAir
I would like to add that longer flights could mean less aircraft utilization. I notice that in the recent AS contract with Skywest, AS wants jets on some of the longer flights into PDX and SEA.

RE: Turboprop Efficiency At Long Distances

Posted: Mon Feb 28, 2011 4:55 am
by kcrwflyer
Quoting cloudboy (Thread starter):
Is there a point, however, where the advantage goes to the jet when you factor in speed and distance traveled? It would seem that for long flight distances the fact that a turboprop flies slower would mean that there is more fuel consumed as the plane is in the air much longer.

Yes, for any given situation there's a point where the two will cost the same and beyond that where the jet will make more sense.

RE: Turboprop Efficiency At Long Distances

Posted: Tue Mar 01, 2011 7:00 pm
by mafi29
Quoting cloudboy (Thread starter):
It would seem that for long flight distances the fact that a turboprop flies slower would mean that there is more fuel consumed as the plane is in the air much longer.

A turboprop consumes way less fuel per unit time than a comparable jet and it still consumes less fuel per unit distance. But at longer distances other facts (as low utilization, less passenger comfort, ...) exceed the fuel savings

RE: Turboprop Efficiency At Long Distances

Posted: Tue Mar 01, 2011 7:44 pm
by Northwest727
Quoting cloudboy (Thread starter):
Is there a point, however, where the advantage goes to the jet when you factor in speed and distance traveled?

In short yes. I just gave a gantleman two charter quotes from Colorado to California in both a turboprop (Beech King Air 90)and a jet (Cessna CJ2). The man, whom we've done business with before, wanted a turboprop (because for whatever reason in his mind-thinks jets are unsafe), and I gave him the quotes. While for short distances, the BE200 is clearly the winner and is a fraction of the cost of a comparible jet, in this case, the BE200 was $1000 more than the CJ2.

RE: Turboprop Efficiency At Long Distances

Posted: Wed Mar 02, 2011 2:00 pm
by Aesma
I have that question but not for current turboprops, rather for an hypothetical long range widebody turboprop with the latest tech. It probably would need to be relatively fast for a turboprop (like the A400M), passenger comfort is not a priority (as I'm thinking about a 200$/barrel of oil world), however on very long flights you have three problems : you carry lots of fuel for a long time, you have to carry lots of catering and water for the passengers, and you need more crew.

But maybe what would make more sense is to forget about long range altogether and go back to the first days of the jet age, when you just made several tech stops. At the time it was because the planes couldn't carry more fuel, now it would be to burn less fuel carrying fuel.

RE: Turboprop Efficiency At Long Distances

Posted: Thu Mar 03, 2011 3:39 am
by 411A
Provided that speed is not a particular concern, a turbopropeller design is far more efficient.
Example.
CL-44 versus B707.
Route, NRT-SFO
Enroute time...B707, 10 hours, CL-44, 16.5 hours.
Payload...the same for both aircraft.
Fuel consumption?
The CL-44 will consume one half as much as the 707.

Varified by the Flying Tiger Line...long ago.

RE: Turboprop Efficiency At Long Distances

Posted: Thu Mar 03, 2011 3:47 am
by 474218
Western and PSA's Electra's were faster and more fuel efficient on their California routes (LAX-SFO, BUR-SAC, SAN-LAX etc) than the 727's that replaced them. I flew the BUR-SAC route many times and the 727's added 15 minutes to the flight.

RE: Turboprop Efficiency At Long Distances

Posted: Fri Mar 04, 2011 3:40 am
by 747400sp
Colgan Air use Dash 8 Q 400 on the Norfolk-Newark route and Horizon/AS also use Dash 8 Q400 on the LAX-SJC routes. the Norfolk-Newark is about the same distance as the jets flown ORF-JFK route, and other airlines use jet on the LAX-SJC routes.


PS: The Dash 8 Q 400 is a pretty fast turboprop, it may be able to keep up with some jets.

RE: Turboprop Efficiency At Long Distances

Posted: Fri Mar 04, 2011 3:54 am
by doug_or
In my observation, yes, a similarly sized TP will be eclipsed by a jet. My observations, are however, based on aircraft built for different purposes.

In this case the DHC-8-300 and the CRJ-200. The Dash was built for shorter field performance and short flights. Its wing, powerplants, and props were optimized fro that. The CRJ-200 is a comparative runway hog, and when taking off in icing conditions has terrible climb performance. It is essentially built for cruise flight.

411a's comparison would probably be better, but is very out of date. I would assume (perhaps incorrectly) that turbo fan technology has come much further than turbo-prop technology has.

I think the closest modern comparison might be the CRJ-700 and the Q400, if anyone has info those.

RE: Turboprop Efficiency At Long Distances

Posted: Sat Mar 05, 2011 1:20 pm
by cobra27
I am kind of surprised at replies here, it is logical that turbrops burn less fuel for distance , but jets outweight in other fields.
When they say that turboprops are better for short hops in terms of fuel fuel efficiency is somewhat misleading, because they are more fuel efficient no matter the distance.

RE: Turboprop Efficiency At Long Distances

Posted: Sat Mar 05, 2011 6:01 pm
by cloudboy
That was the ultimate question. Since a turboprop flies slower, it spends more time flying for a given distance. On a short flight this shouldn't add up to much, but if you had a theoretical long distance turbo prop, at some point it would have to spend so much more time in the air flying the savings in fuel burn per hour would be offset by the extra hours of fuel burn. The question is when is this point reached? Is it a fairly short distance? Or is it so long as to be longer than any possible flight?

RE: Turboprop Efficiency At Long Distances

Posted: Sat Mar 05, 2011 8:22 pm
by tdscanuck
Quoting cloudboy (Reply 11):
On a short flight this shouldn't add up to much, but if you had a theoretical long distance turbo prop, at some point it would have to spend so much more time in the air flying the savings in fuel burn per hour would be offset by the extra hours of fuel burn.

In general, turboprops also burn less per mile. So even though they're in the air longer, the trip fuel burn is still lower.

Quoting cloudboy (Reply 11):
The question is when is this point reached? Is it a fairly short distance? Or is it so long as to be longer than any possible flight?

It's the trade between other costs that are time based, and fuel cost. As you spend more time in the air, utilization drops, flight crew trip costs go up, maintenance costs (which are mostly per flight hour) go up, etc. At some point, the time based costs grow to exceed the trip based costs.

Tom.

RE: Turboprop Efficiency At Long Distances

Posted: Sat Mar 05, 2011 10:03 pm
by wingnutmn
I remember reading somewhere that a Q400 is more economical on stage lengths up to 400 miles over a CRJ700. I believe at 400 miles the Q is only 5 minutes slower. But beyond this point the jet really catches up fast and eventually overtakes on total economics after 500-600 miles.

Wingnut