SheikhDjibouti wrote:

Wikipedia wrote:

BAe RJ85
At 423kn : 2,483 kg (5,474 lb)/h
At 361kn : 1,672 kg (3,686 lb)/h

So.... for a 15% reduction in speed, you get a 33% reduction in fuel consumption.

Your fuel savings are per hour, not per distance.
0,67/ 0,85 = 0,788
A 15% reduction in speed gives 21% reduction in fuel saving in your example.
The question is if both examples are taken at same plane weight.

One could argue that parasitic drag decreases square with speed. 0,85 * 0,85 = 0,7225
But then lift inducing drag has to increase unless one has a longer wing.



source: https://en.wikipedia.org/wiki/Parasitic_drag

A longer wing has extra weight, on the other side a longer wing would allow for a smaller engine. And maintaining laminar flow is easier at lower speeds.
Considering your argument that airlines like to fly fast to save salaries and increase plane utilisation, I guess the typical cruise speed is not at the drag minimum of the curve. So it's likely that your examples earlier were at same weight.
If the governments of a few important countries could agree to limit speed of flights below 2000 nm to 750 km/ h, new planes would get designed accordingly.
More tax on fuel may do the same.

So I guess 20% fuel savings would be a number to aim for. But then most nonsense starts with wrong assumptions.
Anyone knows more?

Sokes wrote:

Pinto wrote:

Maybe it's better to reduce the speed of jets than to increase the speed of props?

Dornier 328JET. Not a huge success.

Just some general observations coming from someone who has flown in turboprops about 5-6 times (EMB-120 Brasilia, ATR 72-200, ATR 72-500 and the Dash 8-Q400):

- The ATR-72-500 was the best experience by far, flew in it twice, once with American Eagle from OKC to DFW, once from IXU to BOM with the now-defunct Jet. Great ride both times, plane sounded pretty much like a jet instead of a prop, and got to the destination in about the same time as a jet.
- The ATR 72-200 (talking the base, 4-bladed prop variant here) was interesting, fully loaded going back to OKC from DFW on a hot day back in August 1999; that thing shot down the runway and launched into the air as if mini rockets were attached to its back side. The sheer vibrations in the cabin during the takeoff run were enough to split a wine glass in two! Then the pilot flying throttled the props back to cruise power and what I heard for the next 75 minutes was the harmony of two turbines and their respective props producing a buzz-whine, if that makes sense. Did I mention it took 25 minutes longer than a jet?
- The Brasilia was ok, I only did a DL mileage run from OKC to DFW and back in 2001 when DL Conn ASA ran these 3 times a day or so in addition to CRJ1s/2s; going south to DFW I sat right next to the propeller and not surprisingly was very loud and the vibrations were... yeah, up there. Coming back I sat in the last row, and while not as loud, made my voice vibrate when I spoke But I did enjoy it, and the plane was quick, 40 minutes in both directions, pretty much the same as a jet.
- The worst experience out of all these of course goes to the one I have not addressed yet - the "Q"400. Nothing quiet about this prop; took it down on what seemed like a never-ending run to IAH when Colgan ran them several times a day to/from OKC. Then took it back to OKC after attending a friend's wedding and pretty much decided not to fly in one again. The props produced a continuous drone in-flight, the cabin continously shuddered (not vibrated, but shuddered - as in moved) to the chord of the props (I did get a free massage out of it but that was the only positive). By the time we arrived at the gate at IAH, I was glad to step out. Return trip was much the same experience, a bit better but not by much. The plane was quick though, did both runs in about an hour and 5 minutes, almost the same time a jet takes.

So I can see why people don't take to props as readily, but the ATR 42/72-500 and now the -600 would be my choice if I were to fly in a turboprop again.

WeatherPilot wrote:

I think the Colgan Air 3407 crash outside Buffalo is what sealed the fate of the turboprop in the US. After that crash people’s perceptions of turboprops changed. The crash had nothing to do with it being a prop plane but it did hurt the image of them with people that don’t know any better.

The problem with both the American Eagle 4184 ATR72 crash and the Colgan 3407 Q400 crashes relates to the primitive flight control system. It is partially related to them being turbo props.
In the case of Colgan 3407 pilot pulled against stick shaker and spun out of control. In case of American Eagle ATR72 flight controls reversed with 250lbs force and aircraft spun out of control.
Both the ATR72 and Dash 8/Q400 use spring tab controls. These are non powered flight control surfaces. In this system steel wire pull cables directly deflect small tabs on the back of the ailerons and elevators, these then use the airstream to deflect the larger control surface. There are springs in the path to the tabs so that they deflect back against the airstream to stop them over deflecting the control surface at too high a speed and over stressing the airframe. In addition there is direct deflection of the control surface by springs as well. They are quite finicky. Such surfaces are very vulnerable to flutter and can be disturbed by turbulence over the wing and need to be set up and mass balanced very carefully. In the American Eagle case the ice made them actually reverse.
Had the Q400 and ATR 72 had fully powered flight controls with FBW systems of the kind used on A320/A220/B787 that offered flight envelop protection the accident probably wouldn't have occurred.
Jets are far less likely to have spring tab systems due to issues such as mach trim and reversal etc. Turbo props often don't have adequate icing systems.
(Incidentally the FAA was criticised for letting the French certify the ATR72 with inadequate icing)

mga707 wrote:

Sokes wrote:

Pinto wrote:

Maybe it's better to reduce the speed of jets than to increase the speed of props?

Dornier 328JET. Not a huge success.

Change this:



source: https://en.wikipedia.org/wiki/Dornier_328

into this:



source: https://en.wikipedia.org/wiki/Fairchild_Dornier_328JET


We speak about a 3 abreast plane which runs on a business jet engine (PW 306).
The turboprop version first flew 1991, just as Bombardier's CRJ 100. So airlines could choose between a 1,82 m broad cabin DO 328 for hardly 30 passengers or a 2,13 m broad cabin CRJ 100 for up to 50 passengers.
What I find interesting is that the wing was designed for turboprop use with 620 km/ h cruise speed. However the straight wing with few changes can fly with a maximum speed of 750 km/ h in the jet version.

about the original turboprop:
" feedback from airlines indicated a desire for a fast, quiet, and easy-to-maintain commuter airliner with a 30-seat capacity.[2] This market research reportedly led Deutsche Aerospace to formulate a sales prediction of 400 or greater units being purchased overall; this forecast was in part derived from the reasoning that the 328 would be more advanced than its nearest competitors.[3] Favourable features included a high cruising speed of 345 kt (640 km/h), as well as a higher cruising altitude and range, making the aircraft almost as fast as jet airliners while being more fuel-efficient; a trend away from spoke–and-hub distribution in favour of point-to-point transit was also viewed as being favourable to the 328.
...
having been optimised for high cruising speeds; the aircraft is capable of higher cruise and approach speeds than most turboprop-powered aircraft, which allows it to be more readily slotted around jetliners during landing approaches.
...
The 328 is furnished with the same supercritical wing design that had been originally developed for Dornier's earlier Do 228; this wing provides the aircraft with both excellent cruise and climb capabilities.[42][5]...The 328 reportedly made greater use of composites than any of its direct competitors at launch, the use of the Kevlar-carbon fiber composites is claimed to have reduced its weight by 20%."
https://en.wikipedia.org/wiki/Dornier_328


"The 328JET was designed by Dornier in response to negative feedback from some customers on the marketability of turboprops against the more appealing turbofan engine. It was a relatively straightforward re-reengining of the existing 328
...
Dornier had planned to conduct a comprehensive upgrade of the existing model, involving an avionics overhaul and possible re-winging to use a new swept wing, around the early 2000s. ... However, a consequence of intense competition within the regional airliner market was multiple manufacturers making losses and terminating their programmes; Fairchild-Dornier were no exception to the industry-wide pressure."
https://en.wikipedia.org/wiki/Fairchild_Dornier_328JET


Fairchild Dornier must have figured that 3 abreast is not so good and planned for a six abreast plane.
And some more marketing input from customers:
" The new family of regional jets, the 528JET, 728JET and 928JET, seating from 55 to 100 passengers was launched at the ILA Berlin Aerospace Show (International Aviation and Space Flight Exhibition) in Berlin on 19 May 1998; prior to this, Fairchild Dornier had received provisional launch orders from German flag carrier Lufthansa, who placed 60 firm orders along with 60 options, and Swiss airline Crossair
...
As a means of preventing low-cost carriers from equipping the 728 with six-abreast seating, instead of Cityline's five-abreast seating, Lufthansa pressured Fairchild Dornier reduce the diameter of the fuselage; this was shrunk from the original 3.40 m (11 ft 2 in) to 3.25 m (10 ft 8 in). The reduction also lowered the weight of the aircraft, but motivated Crossair to move towards the rival Embraer E-Jet family instead; Crossair eventually cancelled their order for the 728, attributing this decision to have been a result of the revised fuselage layout.[22]
...
Prior to the intended date of the 728's first flight being performed, Fairchild Dornier was rendered insolvent and forced to declare bankruptcy on 2 April 2002.[20] One consequence of this was the whole program being immediately brought to a standstill; shortly thereafter, both Lufthansa and GECAS chose to cancel their orders for the type. The withdrawal of the 728's two biggest customers was a considerable blow to the program, potentially putting off investors and partners that were being sought out at this time."
https://en.wikipedia.org/wiki/Fairchild ... 728_family

I think that plane proofs that market studies and customer input are of questionable value. I don't think that plane proofs that low speed jets are not good.

Think people are forgetting that in the 90s, you had two highly publicized AA Eagle turboprop crashes within TWO months of each other - the ATR crash in Roselawn and the J32 crash at RDU. With CRJs coming online (COMAir was a huge early user of them), it was not hard for negative passenger perception to turn decidedly negative.

cougar15 wrote:

peterinlisbon wrote:

Where I have seen turboprops have a lot of success is in countries where the distances are short but the roads are bad. For example, Costa Rica is a small country but it is very mountainous and it can take 8 hours to go 200km. So the turboprops flying to small airstrips can offer an alternative to those that can afford it. Obviously in the US, you could just drive 200km in an hour and a half so it's no contest. Another place where turboprops are popular is for services between small islands.

… and in countries where the environmental impact/green footprint has much higher value than the good old US of A, but I guess that road would lead us to the Non-Av Forum! Enviromentaly friendly Europeans don't mind turboprops on short sectors!

Is this so? We Germans like to separate our garbage and drive SUVs. How many turboprops with major European carriers?


[quote="rouelan"]

Germany has high-speed rail and autobahns where you can drive over 200mph. It wouldn't make sense to go to the airport just to fly a short distance (and for longer distances, there are jets). Compare this with somewhere like Nepal, where a 30 minute Turboprop flight can save a 10 hour bus journey. I doubt the environment has much to do with it anyway.

HugoJunkers wrote:

WeatherPilot wrote:

I think the Colgan Air 3407 crash outside Buffalo is what sealed the fate of the turboprop in the US. After that crash people’s perceptions of turboprops changed. The crash had nothing to do with it being a prop plane but it did hurt the image of them with people that don’t know any better.

The problem with both the American Eagle 4184 ATR72 crash and the Colgan 3407 Q400 crashes relates to the primitive flight control system. It is partially related to them being turbo props.
In the case of Colgan 3407 pilot pulled against stick shaker and spun out of control. In case of American Eagle ATR72 flight controls reversed with 250lbs force and aircraft spun out of control.
Both the ATR72 and Dash 8/Q400 use spring tab controls. These are non powered flight control surfaces. In this system steel wire pull cables directly deflect small tabs on the back of the ailerons and elevators, these then use the airstream to deflect the larger control surface. There are springs in the path to the tabs so that they deflect back against the airstream to stop them over deflecting the control surface at too high a speed and over stressing the airframe. In addition there is direct deflection of the control surface by springs as well. They are quite finicky. Such surfaces are very vulnerable to flutter and can be disturbed by turbulence over the wing and need to be set up and mass balanced very carefully. In the American Eagle case the ice made them actually reverse.
Had the Q400 and ATR 72 had fully powered flight controls with FBW systems of the kind used on A320/A220/B787 that offered flight envelop protection the accident probably wouldn't have occurred.
Jets are far less likely to have spring tab systems due to issues such as mach trim and reversal etc. Turbo props often don't have adequate icing systems.
(Incidentally the FAA was criticised for letting the French certify the ATR72 with inadequate icing)

So what can you tell us about Air France 447 crash? It happened exactly 4 months after Colgan crash. Did that A330 also had primitive flight controls?

OccupiedLav wrote:

There have been a few topics discussing the turboprop market and usage in the U.S., but I can't seem to get to the bottom of why the they are so unpopular here in the states.

As we know, turboprops are slower but far more efficient than small regional jets, and it seems like DL, AU, and AA are often complaining about the high costs of their 50 seat regional jets. On paper, turboprops seem like a viable replacement on flights around an hour long like IAH-CLL, MSP-FAR, or CLT-HXD for example. With fuel price sensitivity and environmental concerns, why are planes like the Q400 and ATR not more common on shorter routes within the U.S?

Passenger preference for jets? High costs of having a subfleet? Too slow? Pilot union/airline agreements?

.


Can you say Lockheed Electra II?

dcaviation wrote:

So what can you tell us about Air France 447 crash? It happened exactly 4 months after Colgan crash. Did that A330 also had primitive flight controls?

The German chancellor Helmut Schmidt was only seen with cigarette in hand and he died 96 years old!

SaschaYHZ wrote:

I don't quite get the hate. I fly turboprops here on the east coast of Canada fairly often (and occasionally between YTZ-YUL) mainly on 1900s and Q400s, and I really don't find them all that uncomfortable or noisy. (ok, maybe the Beech's can be somewhat uncomfortable)

Had a great experience flying Porter BOS-YTZ for a long weekend, then a lousy experience YTZ-BOS because the turboprob could not fly over the summer tstorms between YTZ and BOS so flights were delayed.

washingtonflyer wrote:

Think people are forgetting that in the 90s, you had two highly publicized AA Eagle turboprop crashes within TWO months of each other - the ATR crash in Roselawn and the J32 crash at RDU. ... it was not hard for negative passenger perception to turn decidedly negative.

The final comment is the killer; already negative perception plus a helping of confirmation bias.

As for the first part, in reality it just doesn't hold water.
The commonality? Let's see
Timespan obviously (fresh news is bad news)
American Eagle / American soil / American lives (the Holy Trinity?)
Same manufacturers - er, no.
Countries of origin - er, no (except they were both "Not made here" which always makes a soft target.)
Size - hmm, one had 70 on board, and the other was a 19 seater. So, no again.
Engines - nope.
Age - one was state of the art 1989 technology, the other a warmed over 1960's design with grandfathering written all through it (where have we heard that before? )
That just leaves engine type = turboprop.

I wonder how long it would take me to find two jets that crashed within a short space of each other, say a Embraer EMB-145 and an Boeing 747. That should be enough to put people off from ever flying jets again...…

But you are probably correct; those events were enough the great travelling masses.

SheikhDjibouti wrote:

washingtonflyer wrote:

Think people are forgetting that in the 90s, you had two highly publicized AA Eagle turboprop crashes within TWO months of each other - the ATR crash in Roselawn and the J32 crash at RDU. ... it was not hard for negative passenger perception to turn decidedly negative.

The final comment is the killer; already negative perception plus a helping of confirmation bias.

As for the first part, in reality it just doesn't hold water.
The commonality? Let's see
Timespan obviously (fresh news is bad news)
American Eagle / American soil / American lives (the Holy Trinity?)
Same manufacturers - er, no.
Countries of origin - er, no (except they were both "Not made here" which always makes a soft target.)
Size - hmm, one had 70 on board, and the other was a 19 seater. So, no again.
Engines - nope.
Age - one was state of the art 1989 technology, the other a warmed over 1960's design with grandfathering written all through it (where have we heard that before? )
That just leaves engine type = turboprop.

I wonder how long it would take me to find two jets that crashed within a short space of each other, say a Embraer EMB-145 and an Boeing 747. That should be enough to put people off from ever flying jets again...…

But you are probably correct; those events were enough the great travelling masses.

All good points. It’s also important to remember that “highly publicized” meant something much different 25 years ago than it does now. In Chicago, Roselawn was front-of-mind for weeks, but the J32 accident was barely a blip.

Besides for the 2009 Colgan crash, out in Seattle we seemed to be bombarded daily over the Q400 gear problems with SAS, was it because Horizon was flying lots of Q400's.

In September 2007, two separate accidents due to similar landing gear failures occurred within four days of each other on Bombardier Dash 8 Q400 aircraft operated by Scandinavian Airlines (SAS). A third incident, again with a SAS aircraft, occurred in October 2007, leading to the withdrawal of the type from the airline's fleet.

https://en.wikipedia.org/wiki/2007_Bomb ... _incidents

Between the above incidents, it seemed that Island Air in Hawaii wished it didn't have the Q400. As everyone knows, Island Air died in 2017.

Revelation wrote:

SaschaYHZ wrote:

I don't quite get the hate. I fly turboprops here on the east coast of Canada fairly often (and occasionally between YTZ-YUL) mainly on 1900s and Q400s, and I really don't find them all that uncomfortable or noisy. (ok, maybe the Beech's can be somewhat uncomfortable)

Had a great experience flying Porter BOS-YTZ for a long weekend, then a lousy experience YTZ-BOS because the turboprob could not fly over the summer tstorms between YTZ and BOS so flights were delayed.

On that route, no jet was flying above the thunderstorms, either, too short to climb much above F330 or so. It’s pretty rare for airliners to top summer t’storms on any route and I’ve seen F470 be not high enough.

GF

peterinlisbon wrote:

cougar15 wrote:

peterinlisbon wrote:

Where I have seen turboprops have a lot of success is in countries where the distances are short but the roads are bad. For example, Costa Rica is a small country but it is very mountainous and it can take 8 hours to go 200km. So the turboprops flying to small airstrips can offer an alternative to those that can afford it. Obviously in the US, you could just drive 200km in an hour and a half so it's no contest. Another place where turboprops are popular is for services between small islands.

… and in countries where the environmental impact/green footprint has much higher value than the good old US of A, but I guess that road would lead us to the Non-Av Forum! Enviromentaly friendly Europeans don't mind turboprops on short sectors!

Is this so? We Germans like to separate our garbage and drive SUVs. How many turboprops with major European carriers?

rouelan wrote:

Germany has high-speed rail and autobahns where you can drive over 200mph. It wouldn't make sense to go to the airport just to fly a short distance (and for longer distances, there are jets). Compare this with somewhere like Nepal, where a 30 minute Turboprop flight can save a 10 hour bus journey. I doubt the environment has much to do with it anyway.

-Most SUV's have a top speed of about 200km/h. While there is no speed limit on the autobahn, reckless driving is still not allowed.
-Try driving around Frankfurt or any major German city around rush hour. You'll be happy to drive 20km/h.

The reason why turboprops are not popular in Europe are the same as in the U.S.
Not sexy enough for someone to invest money in it, not sexy enough to interest politicians, big airlines want to fry bigger fish using A320/B737 that have low unit cost, anything smaller is not worth their time/consideration.
In the meantime, everyone flies the same routes and everyone complains that they can't make sense of it and people in smaller cities complain that they don't have access to fast domestic transportation.
Autobahn is a solution but if you need to cross the country from regional city to regional city, you are still losing an entire day, even within domestic Germany.

The demand exists, no one is addressing it.

Waterbomber2 wrote:

The demand exists, no one is addressing it.

Because the demand does not actually exist in the public market place.

Therefore, since there is no real market demand... No aircraft company is going to drop $5-$7 Billion too develop a modern comfortable fuel efficient and reasonably quite medium sized turbo-prop (to cover the 30-70 person market). No engine manufacturer will spend the money to develop a modern fuel efficient engine at those small power levels.

Perhaps you and your friends could start an "go fund me" page (or similar) or otherwise interest investors and come up with a $5 Billion dollar deposit for such a project.

Have a great day,

OccupiedLav wrote:

lightsaber wrote:

Partially it is speed. If flying, why not save time? The other is fear of propellers. I know numerous people, not a majority, but enough, who dislike turboprops enough they will drive instead of flying.

On short routes, does the difference in speed really matter that much? I imagine on some routes the regional jets don't have enough time to reach higher altitudes and cruising speeds, so the turboprops wouldn't really take that much longer to reach the destination. I could be wrong. Time sensitivity is very crucial.

As far as passenger aversion to propellers, couldn't some marketing/education on the safety and efficiency of turboprops solve the problem? Ex.: "Our new jet powered turboprops get our passengers to their destinations using 25% (don't know the exact number) less fuel than traditional regional jets"

This. I fly NTL to BNE in Australia often. I can take an A320 or 737 and it takes 1 hour usually. I take Qantas on the Q400 and it usually takes 1 hour 5minutes.

Waterbomber2 wrote:

peterinlisbon wrote:

cougar15 wrote:

… and in countries where the environmental impact/green footprint has much higher value than the good old US of A, but I guess that road would lead us to the Non-Av Forum! Enviromentaly friendly Europeans don't mind turboprops on short sectors!

Is this so? We Germans like to separate our garbage and drive SUVs. How many turboprops with major European carriers?

rouelan wrote:

Germany has high-speed rail and autobahns where you can drive over 200mph. It wouldn't make sense to go to the airport just to fly a short distance (and for longer distances, there are jets). Compare this with somewhere like Nepal, where a 30 minute Turboprop flight can save a 10 hour bus journey. I doubt the environment has much to do with it anyway.

-Most SUV's have a top speed of about 200km/h. While there is no speed limit on the autobahn, reckless driving is still not allowed.
-Try driving around Frankfurt or any major German city around rush hour. You'll be happy to drive 20km/h.

The reason why turboprops are not popular in Europe are the same as in the U.S.
Not sexy enough for someone to invest money in it, not sexy enough to interest politicians, big airlines want to fry bigger fish using A320/B737 that have low unit cost, anything smaller is not worth their time/consideration.
In the meantime, everyone flies the same routes and everyone complains that they can't make sense of it and people in smaller cities complain that they don't have access to fast domestic transportation.
Autobahn is a solution but if you need to cross the country from regional city to regional city, you are still losing an entire day, even within domestic Germany.

The demand exists, no one is addressing it.

Amen to that. At least for Europe. Here in France some senators recently did a study of how beneficial is a Turboprop connection to major cities from remote region. Railwayand highway are not systematically the solution (at least in EU)

A380MSN004 wrote:

...
Here in France some senators recently did a study of how beneficial is a Turboprop connection to major cities from remote region. Railwayand highway are not systematically the solution (at least in EU)

Did ATR finance this study?

Sarcasm aside you are of course right. The tricky part is to find the balance.

2175301 wrote:

Waterbomber2 wrote:

The demand exists, no one is addressing it.

Because the demand does not actually exist in the public market place.

Therefore, since there is no real market demand... No aircraft company is going to drop $5-$7 Billion too develop a modern comfortable fuel efficient and reasonably quite medium sized turbo-prop (to cover the 30-70 person market). No engine manufacturer will spend the money to develop a modern fuel efficient engine at those small power levels.

Perhaps you and your friends could start an "go fund me" page (or similar) or otherwise interest investors and come up with a $5 Billion dollar deposit for such a project.

Have a great day,

On the investment side, the demand does not exist, not sexy enough. That's what I'm saying.

However, on the travel demand side, the demand exists and is only becoming more acute as young people leave rural area's to work in the cities. In fact, most of them don't want to leave the rural area's and would rather have an option to commute.
As much as jets have opened up intercity connections, they have isolated many smaller communities, expecting them to travel sometimes to airports hours away. Big airports are becoming bigger, small airports are struggling to stay open.
This is as true for the U.S., as it is for China or Europe.

2175301 wrote:

…. the demand does not actually exist in the public market place.

Waterbomber2 wrote:

On the investment side, the demand does not exist, not sexy enough.

Between the two comments, I expect you've covered it.
Demand doesn't always arise organically. Sometimes it needs a helping hand. Or advertising.
Sometimes it is a case of "if you build it, they will come"
Sometimes it is a case of educating the public i.e. pointing out they are worshipping false gods (=jet engines).
That happened with mink coats. Every woman wanted those once; now where are they?

The vehicle below is built like a tank, has a 6.0 liter engine, and can tow a house.
But how often do you suppose it does any of that, as opposed to pampering just the driver, and maybe a six-pack from the liqor store.
But they sell like hot cakes - everybody just has to have one. Is it sensible, is it justified? Or is it just hype?
(p.s. do I get a bonus prize for the a/c in the background...)

No aircraft company is going to drop $5-$7 Billion too develop a modern comfortable fuel efficient and reasonably quite medium sized turbo-prop (to cover the 30-70 person market). No engine manufacturer will spend the money to develop a modern fuel efficient engine at those small power levels.

No need to. Fuel efficient turboprop aircraft & engines already exist. The engines are called the "PW100 series"
Or there is the Allison (RR) AE2100, fitted to thousands of Lockheed C-130J (& the occasional Saab 2000)
Or do we really need a brand new design, to save people from flying on a warmed over 1960's airframe. Oh wait.....

Which leads us neatly on to the question; why are turboprops the engine of choice for small/medium military transports? Is it because air forces around the world buy what best gets the job done, and are not victims of fashion?

SheikhDjibouti wrote:

2175301 wrote:

…. the demand does not actually exist in the public market place.

Waterbomber2 wrote:

On the investment side, the demand does not exist, not sexy enough.

Between the two comments, I expect you've covered it.
Demand doesn't always arise organically. Sometimes it needs a helping hand. Or advertising.
Sometimes it is a case of "if you build it, they will come"
Sometimes it is a case of educating the public i.e. pointing out they are worshipping false gods (=jet engines).
That happened with mink coats. Every woman wanted those once; now where are they?

The vehicle below is built like a tank, has a 6.0 liter engine, and can tow a house.
But how often do you suppose it does any of that, as opposed to pampering just the driver, and maybe a six-pack from the liqor store.
But they sell like hot cakes - everybody just has to have one. Is it sensible, is it justified? Or is it just hype?
(p.s. do I get a bonus prize for the a/c in the background...)

No aircraft company is going to drop $5-$7 Billion too develop a modern comfortable fuel efficient and reasonably quite medium sized turbo-prop (to cover the 30-70 person market). No engine manufacturer will spend the money to develop a modern fuel efficient engine at those small power levels.

No need to. Fuel efficient turboprop aircraft & engines already exist. The engines are called the "PW100 series"
Or there is the Allison (RR) AE2100, fitted to thousands of Lockheed C-130J (& the occasional Saab 2000)
Or do we really need a brand new design, to save people from flying on a warmed over 1960's airframe. Oh wait.....

Which leads us neatly on to the question; why are turboprops the engine of choice for small/medium military transports? Is it because air forces around the world buy what best gets the job done, and are not victims of fashion?

Well we are just talking about GTF engines with a quite high BPR which happens to be unducted.

Both ATR's and Q-400's are based on old designs and no OEM is willing to look at a clean sheet design. The airlines don't want them and the same for the flying public. The next-gen RJ's are getting better on fuel economy and better off short runways. Bottom line is that the prop is past generation design, no mainline props are flying or on the drawing board, so no matter how some think the prop will make a comeback, the sales are in drips and drabs with the ATR getting the bulk of the sales which still are in low numbers. RJ's sales are high and airlines are adding more every year and if the sope clause can be modified, more orders will follow.

SheikhDjibouti wrote:

Which leads us neatly on to the question; why are turboprops the engine of choice for small/medium military transports? Is it because air forces around the world buy what best gets the job done, and are not victims of fashion?

Military transporters are supposed to start from short strips of grass.

The media made full use of this image:



Won't ever be forgotten by the public.

Sokes wrote:

SheikhDjibouti wrote:

Which leads us neatly on to the question; why are turboprops the engine of choice for small/medium military transports? Is it because air forces around the world buy what best gets the job done, and are not victims of fashion?

Military transporters are supposed to start from short strips of grass.

It's nice to have rough-field capability, but the reality is they hardly ever perform that task.
Besides, a properly configured jet a/c can do exactly the same.

I once took a photo of CCCP-72000, directly over my head, totally inverted. (Fortunately I was off-airport, nowhere near the crowd-line )
The pilot did get a ticking-off from the authorities for that indiscretion, and probably a nice bonus when he got back to Russia.
The photo on the right is from Paris, 2003, and is a severely toned down version of what I (and a few hundred others) enjoyed.

Anybody remember the AMST program?
The Boeing YC-14 and McDonnell Douglas YC-15 were both candidates to replace the turboprop C-130.
Fun fact; To save costs, the YC-15 used a modified DC-8 nosewheel unit and the DC-10 cockpit, adapted for a two-person crew, with two lower windows for visibility during short-field landings.


And just for LOLs, here's a rather enthusiastic C-160 Transall pilot, slapping it down on it's nose. Good job it wasn't a Dash-8.

SheikhDjibouti wrote:

And just for LOLs, here's a rather enthusiastic C-160 Transall pilot, slapping it down on it's nose. Good job it wasn't a Dash-8.

Cool picture. As we are already at it:



source: https://commons.wikimedia.org/wiki/File ... A_2016.jpg

United787 wrote:

I would put a lot of it on AA 4184, the 25th anniversary which is coming up in two days on Halloween. I remember the night clearly because I was living in Champaign, IL at the time and we tried trick or treating in the same storm, it was a horrible night.

https://en.wikipedia.org/wiki/American_ ... light_4184

I remember that one vividly too. My best friend's Dad was on that flight. He'd taken an earlier flight to get back to RDU (via ORD) a few hours early.

I too think that one was a big contributor and AA's response of moving all those ATR flights to other hubs didn't help people's confidence. Here at RDU, we had another turboprop crash (J32) about 6 weeks later in December of '94. For whatever reason, the 90's seemed to be a bad decade for turboprops.

https://en.wikipedia.org/wiki/Flagship_ ... light_3379

A380MSN004 wrote:

Here in France some senators recently did a study of how beneficial is a Turboprop connection to major cities from remote region. Railwayand highway are not systematically the solution (at least in EU)

To be more precise, I think it was about expanding the PSO scheme. And, even if local politicians dont like it they know only turboprop operators will bid as they cant afford to subsidize a jet.
Think of recent examples where subsidies per pax are up to 100€ with ATR. More than the price of a TGV ticket which will bring you from Quimper to downtown Paris in 3h40. I would like to meet with these senators and redo the maths to find the benefits

JayinKitsap wrote:

Besides for the 2009 Colgan crash, out in Seattle we seemed to be bombarded daily over the Q400 gear problems with SAS, was it because Horizon was flying lots of Q400's.

In September 2007, two separate accidents due to similar landing gear failures occurred within four days of each other on Bombardier Dash 8 Q400 aircraft operated by Scandinavian Airlines (SAS). A third incident, again with a SAS aircraft, occurred in October 2007, leading to the withdrawal of the type from the airline's fleet.

https://en.wikipedia.org/wiki/2007_Bomb ... _incidents

Between the above incidents, it seemed that Island Air in Hawaii wished it didn't have the Q400. As everyone knows, Island Air died in 2017.

WP went under because they tried to compete head on with HA instead of sticking to the commuter routes it had traditionally operated. The Q400 may have worked for WP, problem is, they didn’t have enough of them. No way for them to compete on frequency inter island with the handful they had. They then purchased used ATR72s but faced the same issue.

WP should have picked up some 500/600 series ATR42s which would have allowed them to access to JHM, MKK and LNY. While WP was going through multiple identity crises HA brought in Empire to operate AT4s and filled the niche WP traditionally served, themselves.

77H

dcaviation wrote:

HugoJunkers wrote:

WeatherPilot wrote:

I think the Colgan Air 3407 crash outside Buffalo is what sealed the fate of the turboprop in the US. After that crash people’s perceptions of turboprops changed. The crash had nothing to do with it being a prop plane but it did hurt the image of them with people that don’t know any better.

The problem with both the American Eagle 4184 ATR72 crash and the Colgan 3407 Q400 crashes relates to the primitive flight control system. It is partially related to them being turbo props.
In the case of Colgan 3407 pilot pulled against stick shaker and spun out of control. In case of American Eagle ATR72 flight controls reversed with 250lbs force and aircraft spun out of control.
Both the ATR72 and Dash 8/Q400 use spring tab controls. These are non powered flight control surfaces. In this system steel wire pull cables directly deflect small tabs on the back of the ailerons and elevators, these then use the airstream to deflect the larger control surface. There are springs in the path to the tabs so that they deflect back against the airstream to stop them over deflecting the control surface at too high a speed and over stressing the airframe. In addition there is direct deflection of the control surface by springs as well. They are quite finicky. Such surfaces are very vulnerable to flutter and can be disturbed by turbulence over the wing and need to be set up and mass balanced very carefully. In the American Eagle case the ice made them actually reverse.
Had the Q400 and ATR 72 had fully powered flight controls with FBW systems of the kind used on A320/A220/B787 that offered flight envelop protection the accident probably wouldn't have occurred.
Jets are far less likely to have spring tab systems due to issues such as mach trim and reversal etc. Turbo props often don't have adequate icing systems.
(Incidentally the FAA was criticised for letting the French certify the ATR72 with inadequate icing)

So what can you tell us about Air France 447 crash? It happened exactly 4 months after Colgan crash. Did that A330 also had primitive flight controls?

Air France AF447 was French and had poor quality French Thales Pitot Static sensors. Everyone else had proper robust sensors by Goodrich or Honeywell.

OccupiedLav wrote:

This is a good point. I was wondering how airlines would persuade pilots to fly turboprops. Correct me if I'm wrong but not gaining jet time could be a major issue with the pilots flying turboprops.

Turboprop and jet is all the same for pilots, all counts as “turbine time”. King Air and 777 are the same as far as building hours and experience goes.