The Dassaults are also very interesting to me. Its pretty interesting that they're the only trijets still in production, and yet they are so popular, so I always try to read about them.

In response to these questions, my understanding is that the Dassault isn't necessarily safer overall than the Gulfstream. There are safety performance tradeoffs. The Gulfs can run all their systems off one engine, and then they can run almost everything off the APU. And then even without the APU, there are the multiple redundant hydraulic accumulators, ram air turbines, batteries, etc, to be able to run enough systems to land the thing. Plus the Gulfstream is the bigger plane with better thrust (with all engines) so it should be able to power through weather better.

As far as ETOPS: yes for the planes that are operated as charter, but I don't think that private operators have to comply with ETOPS. They can do whatever they want.

All a myth... all unsupported... all of Dasso's marketing propaganda... and you bought it all apparently... :)

With today's technology and reliability-- not to mention the power of modern twin engine long range bizjets and airliners, the three-hole thing is a MYTH.

For example-- A G150 can fly just as far on one engine as they can on two... with 2 TFE731-40AR's. The competitor from Falcon? The Falcon 50, which is no longer made...

You think a falcon 900 with one engine out can stay "in the flight levels and not descend"? Especially in higher ISA temps over the atlantic? Even a 7x would not be able to just keep cruising along like nothing happened with one engine out. You would have to descend in any scenario. If it is a twin, you would definitely crank the APU up-- at a staggering 100-200 lbs an hour (sarcastic):rolleyes:-- and with little to no effect on speed limit (on any of the twins I have flown).

Dasso used to also claim that winglets were "a product of poor aerodynamic design" when comparing their models to Gulfstreams... now every falcon has a retro-fit kit for winglets (including now the 50), and every new model has winglets... Just as with their winglet myth, the 3-hole myth is kaboomed outta here. :eek:

ETOPS for private aircraft in the US is not enforced, however Gulfstream ensures that it's product line can meet or exceed the specifications in ETOPS. I am sure other manufacturers do as well (if not all of them), that is just the one I know about.

Unsupported?

There is definitely no "myth" on the operating economics...

Annual Budget (no depreciation)

Falcon 7X/ G550

Utilization (nm.) 175,000/ 175,000
Utilization (hours) 407/ 413
Variable Cost $1,126,832/ $1,363,016
Fixed Cost $717,506/ $827,531
Total Cost $1,844,338/ $2,190,546
Per nm $10.54/ $12.52
Per hour $4,532/ $5,304
Per seat mile $0.88 / $0.70
Typical price/1000 (mil.) $47,400/ $48,995

Source: Conklin & deDecker Aircraft Cost Evaluator 2009 vol. 1 v. 4.8.0

IMHO, Dassault marketing is brilliant. They have marketed an aircraft that sells for $1,595,000 less; and in terms of an annual operating budget, an owner can utilize the 7X for 16% less than a G550.

All with an extra engine...why not market triple redundancy for less money?

Comparing a 7x and a 550 is not a "true" comparison!! I could compare a G150 to a Falcon 2000 and it would kick the crud out of it from an operating budget!!

The fact that you are trying to discounts your credibility!!

I never said that dasso's marketing was poor!! I said the MYTH of 3 being better than 2 is just that.. a myth! Any pilot that buys that myth needs to do some research!!

You may "breathe easier" before you cross the atlantic with 3 engines (completely in your head, btw), but you will also be waiting for 3 engine starts for something to fail... 3 times more likely to have something break, and also statistically 3 times more likely to have an engine failure over a 2 engine aircraft.

Let's not throw out a "straw-man" to make an argument. If you have the data that can be referenced, please use it. Otherwise, subjectively validated personal insight is blatantly anecdotal. On that point, how can the comparison between two bellwether intercontinental business jets not be accurate?

You referred to "unsupported marketing propaganda" from Dassault. The categories of Product, Place, Promotion and Price are all positive. If you do not like the credibility of the data that was referenced from Conklin and deDecker, then you should direct your displeasure towards them.

Please don't kill the messenger.

Ugh... there is no "debate" here...

Don't you dare tell people on here that they are throwing out "personal insight" and trying to pass it as fact. You have no idea what people's backgrounds are in here, including mine. You think it is an "argument", which again makes me think you are taking this too personally.

Second, I actually said dasso's marketing is quite good!! THEY STILL HAVE YOU CONVINCED! :)

Third, 2 engines are always better than 3. You can say it is my opinion all you want, but it is a fact.

Fourth, and once again... the comparison between the 7x and the 550 is not a TRUE comparison because the 550 is A LOT more aircraft than the 7x... more aircraft=more $. ONCE AGAIN-- comparing a 7x and a 550 is like comparing a G150 and a 2000ex and saying the G150 is better because it is more cost efficient... completely different aircraft...

Clear?

Please compare another aircraft and supply supporting evidence if the G550 is not congruent with your expectations.

Research and data establishes the dichotomies of debates (perceived or not), not the interrogative of: "Clear?"

"You can say it is my opinion all you want, but it is a fact."

Subjective.

Not true. Dassault is very much technically right. Extra wingspan is still more efficient than a winglet of the same length. There's a reason why long range Boeings don't have winglets. For the older Dassaults with the winglet retrofit kits, its a matter of loading. Those winglets are what the wing could structurally handle. Presumably a wing extension would have been more efficient but would have been too stressful on the wing. They are a compromise. Same thing with the 7X, actually. The winglets got added to the 7X design when Dassault changed their design goal from 5,700nm to 5,950nm, including an increase in MTOW, while they left their wing design mostly frozen. They could have made a more efficient plane if they went back and did a more substantial redesign to the wing to increase its length. Instead of spending the money to do that, they added winglets. Again, a compromise on total performance.

So maybe you could argue that winglets have proven to be a good structural / performance tradeoff, but even then you'd have to figure out why Boeing, a very aggressive winglet implementer, leaves them off of their long range 777s, 787s, and 747s.

Extra wingspan > winglets is still definitely the case

I don't know why QuietSpike is so defensive, but I do agree with him as far as saying that Dassault isn't necessarily safer than Gulfstream. Maybe has something to do with the fact that he is named after a Gulfstream research program :rolleyes:.

The deal is that you're thinking, "oh the Dassault is safer because it can lose one engine and still have 67% of its power, and it can lose 2 engines and still have power." Well yeah and thats part of the safety tradeoff, but these turbofan engines are EXTREMELY reliable. Chance of failure of any one engine is something like 2% per 1000 flight hours. So most of the time you're going to have all your engines, and in that case the Gulfstream is going to have significantly better thrust and be able to power through dangerous situations better. Also, since the Gulfstream has much higher thrust to weight with all its engines, the Dassault's thrust to weight advantage with an engine out is relatively modest. Its not the difference between 50% and 67%. The Gulfstream has almost 20% more thrust to weight than the Dassault so with an engine out the comparison is something like 60% for the Gulfstream vs 67% for the Dassault, if that makes sense (basing all engine thrust at 120% for the gulfstream, 100% for the Dassault).

Either plane has all the redundancies that they need to be able to run all the systems with an engine out. In fact, before the 7X's improved systems, Gulfstreams were known for having better redundancies than Dassaults. Either plane be flown with all power out.

Also, engines aren't the only consideration for engine out performance. The wing is a huge factor. If the Dassault wing is slightly more optimized for high speed flight than the Gulfstream's (as it technically could be since it uses high lift devices more aggressively), then that could be the difference between the Dassault and Gulfstream's with engine out power. The Dassault would have a little more thrust, but the Gulfstream's wing would be a little more suitable to the lower speed flight that you'd be doing with an engine out. I'm not saying that this is definite, I'm just trying to convey the true safety difference between 2 engines and 3: not necessarily anything.

As far as efficiency, yes it is cheaper to run and uses less fuel. It also has about 10% less cabin volume than the G550 and can't fly quite as long, and is a newer design. The Dassault is more fuel efficient because it is so much lighter. BOW of 35,000 lbs vs 49,000 lb in the Gulfstream. Thats a huge difference, and yet the fuel savings isn't that huge. This is the way that Dassault gets better fuel efficiency while having 3 engines: their planes are MUCH lighter. 2 engines would have been more fuel efficient than 3. The dominant factor in choosing 3 engines is engine availability. There simply aren't modern and efficient engines available in the thrust class that would be needed to power the 7X. So Dassault figures that they can build the plane the 3 PW+C engines which are very popular and considered safe and efficient, and they'll still get better fuel economy than the competition by virtue of their plane being 30% lighter than the competition.

There are obviously a lot of tradeoffs 2 engines vs 3. However, overall, from an engineering standpoint, 2 engines is overall better. Like I said, its a matter of engine availability. Back in the day (the 1960s) all the purpose built business jets were small and relatively short range. The engines built for them offered maybe 3,000 or 4,000 lb of thrust. They were considered to be less technologically advanced and less efficient then airliner engines of the day, and also were relatively expensive to buy and service. So Gulfstream innovates by just saying, "we're going to build our plane around low end commercial airliner engines, which have much higher economies of scale and are better developed, and we're going to be able to give people much more airplane at a relatively good value". Then Dassault responds with the Falcon 50 by saying, "we're going to actually put some engineering into this problem and create an efficient S-Duct trijet so that we can give people the plane and range that they need at a much lower price than the Gulfstream".

And thats where they still are today. However, I predict that there will not be any more new Dassault trijet designs. They are over after the 7X. Every single engine make is currently working on engines in the current 10,000lb to 13,000lb gap where there are no good engines available. Without a gap between where efficient purposebuilt business jet engines end and where efficient commercial airliner engines begin, there's zero reason for trijets.

Tuna hp,

Thank you for your professional, lucid, and data laden insight. In the end, macroeconomics, mission, and marketing will be the final arbiters to the customer.

Life-cycle costing is a consideration as well. I was surprised to see that the 7x only requires 0.70 maintenance hours per flight hour compared to the G550's 1.53 maintenance hours per flight hour. Engine restoration costs are budgeted at $513 per hour on the 7X vs. $622 per hour on the G550. This is on top of the leading fuel efficiency from the 7X.

All of this seems counter intuitive...you can operate three engines on less fuel, and you can complete HSI/MPI/overhaul on three P&W 307's for less than two BR 710's. Again, this data is according to Conklin & deDecker's Aircraft Cost Evaluator 2009 vol. 1.

From the operational and budgeting perspective, the 7X does have it's nose in front; but I would be happy to operate either one.

When you think about it, its not really counter intuitive. The BR 710s are much bigger engines. They're making 60% more max thrust. So they use 20% more fuel and have 10% higher maintenance cost? Big deal, they're providing a higher thrust/weight ratio to an airplane that weighs 30% more. The BR710s probably have much better "thrust specific fuel consumption" than the PWC307s if they are only using 20% more fuel.

Still, it is amazing that the 7X weighs 30% less than the G550. Its smaller, but not that much smaller. They really build a good airplane.

Ugh... I give up... do the research on your own... I have given countless examples of why that is not a TRUE comparison... you have failed to see them.

Great - but were not talking about old Boeings here.

We have flight planning services, ultra-nav, EFB-Prob, etc...and common sense. I know, whippersnappers who dont really know how the charts work..

We can quickly come up with a max (or slightly more conservative actually) numbers and go from there. No mistakes made, no lines drawn wrong. Ever watch the average pilot struggle through the useless exercise the sim centers drag ya through during recurrent? I'd say the spread of answers in the average recurrent is about 50% +/- what the real number is.

Anyone who thinks people sit there and whip out OEM graphs and rulers in their 7X, GLEX, or G550 has likely never flown one.

Tuna - where do you get your bizarre numbers? 20% more fuel? Its much higher than that, closer to 35%.

Geo - your mx numbers are way off. Wait until a 7X comes up on a C check - based on the multiple X factors A/B checks are coming in at it will be downright scary. Falcon has recently completely halted offering FalconCare on 7Xs until they can grasp what these costs are. Those that got in on FalconCare have added huge value to their planes on the market.

Now...get back to flightsim boys!

True.

Good for you but your attitude is what I find most interesting. "What the hell?" "Cessna drivers". " Now...get back to flightsim boys!"

I would think an aviator with such experience and such credentials ("I've flown all three) would take the time to educate and inform rather than berate and insult. The contempt is palpable. And disgusting.

Not eennntirely accurate--- the difference between extra wing (like the raked winglet of a 764, 773, 772LR) and a winglet are so minute, it is a draw.

Defensive? If that is they way it sounds when I post, then you are reading it differently then how I am "saying" it... I dont get defensive about facts!! :)

People have really strayed off topic with this--- the fact is 2 engines are better than 3 TODAY. There was a time in the history of aviation for 3 holers, and I loved them... L1011 is still one of my fav pax planes of all time! Falcon still makes 3 holers... so they are still going to try and sell the 3-eng-are-safer-than-2 idea! Why wouldnt they!?

Side note: Falcon (and others) also tried to say that gulfstream could never get any windows larger than the ones on the I, II, III, IV, V, 350, 450, 550... which is *exactly* why the 650 windows are 16 percent larger!! Out of spite!! :)

Busted with my name Tuna... but I dont work there anymore (laid off due to economy last year), so there is no loyalty here to any manufacturer... I just call it like I see it nowadays!

Conklin de Decker 2009 says 18.5% more fuel. And your 35% number is impossible. The G550 only carries 29% more fuel than the 7X, and it should go over 10% farther at M.85. It is truly scary that people's lives are in your hands when you have no idea about the characteristics of the planes you fly and you have such an unprofessional attitude towards safety.

Someday I'll take you for a ride in a real jet ;)

All of those previously mentioned biz jets have got too many engines to be efficient (says the Pilatus pilot;)).

I do, however, miss the "three-holer" from my previous job - the one built by Boeing.

It is fun, though, to think that I now cruise for an hour (longer, actually) on the same fuel we used to plan for TAXI in the 727. Of course...during that entire hour, I keep chanting "turbines don't quit, turbines don't quit..." lol Apples and Oranges, I know - but fun to see the contrasts.

Sorry - just had to throw that in there. You may resume your regularly scheduled argument.

Maybe you can design a 3 engine gulfstream on your fliightsim program and make up some great performance data to share on the internet. Wouldnt that be super cool?

What would be super cool for us lowly Cessna pilots is for some bigjet real world, common sense aviator to regale us with exciting stories of how it is really done. I mean with EFBs, glass and computer flt plans. And efemesses too... :rolleyes:

What is your problem? The certified max fuel load on the G550 is only 29% more and you yourself as well as other people who have flown both planes have both repeatedly said that the G550 is a much longer range plane that will fly farther at the same speed. Your 35% number is clearly way off, so just admit it. I don't know who you work for, so I can't warn them of how incompetent their pilot is anyway.

I think it would be really neat if we could put the G550 engines on my buddys batman airplane, which has the super efficient 7X type wing. Then I bet it gets the same range as the Fusion Global FBW, which will outlfy the G650.

Most operators would plan routes to stay within an acceptable range of adequate airfield in case of emergencies. The most crucial emergencies dealing with degraded aircraft performance. So far everyone has been quick to point out just the loss of power in an OEI situation. But what about performance. Basic multi engine doctrine taught that with an engine failure on a twin aircraft. Not only did you lose half the power, but suffered an 80% degradation in aircraft performance. This being because now the failed engine is dead weight creating only drag. Most twin jets have nacelles and engines that have bigger surface area than the competing 3 or more aircraft.
So when you lose an engine on a trijet sure you've only lost 1/3 the power, but performance wise. Smaller engine, less weight, less drag. This probably means you can continue to cruise at higher altitudes and speeds for the given weights, temperatures, and etc. It was about 2 years ago that British Airways 747-400 lost an engine on departure out of LAX and continued it's flight to London. Would an twin engine whatever have done that? I am only using the BA flight as an example, I am not commenting on whether is was wrong or right.

I'd add that in addition to drag from the dead engine, you also have your centerline of thrust way out to the side at the nacelle with the working engine. So you have to waste a lot of energy to fly straight. Trijet, if you lose the center engine you still have centered thrust. If you lose an outside engine, the centerline of thrust is still only half way to the nacelle, so you should have to waste less energy to fly straight.

Maybe, but what if when people are designing airplanes, when they have a twinjet versus a trijet they know that they are going to be able to have 20% more thrust so they are able to build a bigger wing for the plane. And when an engine goes out they'll have somewhat less thrust to weight than the trijet, but they'll have more wing to weight. Which is safer?

QuietSpike,

I simply compared the top-of-the-line Falcon product with the top-of-the-line Gulfstream product- both of which are suited to global operations. You have the right to disagree with my research of the two products that I chose (with a supporting macro breakdown from an outside source.) However, simply disagreeing without backing yourself up with data makes for a weak retort...

To that end, fly safe and remember:

"It is the mark of an educated mind to entertain a thought without accepting it"

-- Aristotle

(that was a compliment to you)

Traditionally I am a fan for having more wing. But this usually pertains to the mid-size aircraft size. Again for better runway, and hot & high performance. However with more wing comes more lift, and more drag. Both induced and parasitic. Also while larger wings are more conducive to takeoff performance, they are a hinderance in the high speed flight regime. It all comes down to what you're trying to accomplish performance wise for the aircraft.

Unless the more wing and more engine allows them to climb higher where there air is thinner... I think it would be interesting to understand that tradeoff, I doubt anyone on this forum understands it.

Geo...dont take this the wrong way!!

I used to sell gulfstreams... it was my job to know their performance and limitations along with each and every competitor out there. to say I "know" about these planes is an understatement...

To change someone's mind in a forum like this would take an act of congress (and even then, you know they wouldnt get it done!;))

So I just gave up... I had given my two cents, it was discarded... no hard feelings!

-spike

Good point Tuna!!

Look at the U-2.. huge wing area, and ultra-high performance (albeit slllooowww).

Look at the G550 wing-- huge wing area (against other similar planes), and has low ref speed and high cruise speed. The G650 will be similar-- completely new wing, but similar ref speeds and a .90 normal cruise!

The G550 has huge wing, great climb performance, and great cruise performance.... and not leading edge slats... that has to say something about the designers!! :)

The real advantage of three engines is, in the event of OEI, one is not required to land, one can continue, if the performance allows. That is, you have the MEA accounted for. In the end, once an engine dies, a twin is now a single-engine plane not going far. ETOPS is a consideration for everyone who wants to run a airline-grade operation.

The BA 747 is an example of four-engine capability.

GF

So I guess you are saying the lockheed jetstar was the safest bizjet because it had 4 engines...

This is like a Motor Trend debate--- my car has 8 cyl engine... oh yeah, mine has 12, so it must be better...

doesnt work that way! :)

Quiet Spike

Nowhere did I use the word "safer", I used "advantage". With over 4,000 hours in four-engine planes and 2,500 in international two-engine. bizjets, I believe safety isn't the issue, but capability with an engine shutdown is. Admittedly, not a large issue, but could be a telling one for trans-polar, trans-Siberian or long Pacific flights.

For example, PANC -UUWW, would you really want to put your plane and pax into BGTL after a engine loss or fly for 4 hours on one to northern Norway. The other option is a flight at lower latitudes and much greater distance and time

GF

Overheard on Center the other day...conversation between a 7X crew & DA-2000. 7X was at 450 (or somewhere around there)....DA2000 was in the mid to high 30's. They asked what model the Falcon was at 450. 2000 crew asks the 7X how they like the a/c.....they said "it's great, if you like doing avionics/data "reboots"..(or something to that effect).

I'm sure the 7x is a fine a/c, but it sounds like it's having teething pains from being the"A" model. I've never heard a G-V/550 crew complain about their bird openly.....not to say it hasn't happened.

Carry on...

Every new aircraft has it's glitches that needs to be ironed out. G150 has the proline 21 system that's been around for years and it's been known for having to "reboot" or make a dark aircraft on occasion. But it's still a great airplane.

Flown any of the above aircraft? or just getting all these conclusions from an overheard radio conversation?

You have never heard G5 pilots complain about the APU? the brakes? screens going blank?

Maybe ask the next one your hear flying overhead?

No, I haven't. I was just relating a story I heard on center a few weeks ago. I 'm fully aware that new a/c have teething pains.

No need to get all worked up.

Back to your Falcon vs Gulfstream battle...

This is normal and not just a Falcon thing. The G4 brake by wire system was so bad that GAC actually started re installing hydraulic brakes. The G5 hydraulic system was so bad that GAC had to take out all the dual Vickers pump systems and replace them with a single Abex pump system. Ask any G550 pilot about tubes blanking out with certification c.

G4G5 has it right.

I cannot speak for the Gulfstreams (never flown them), but I can for the 7X. I have done my fair share of "re-init"s (power down, wait 5 min, power up) to clear fault messages and it is frustrating, but not as often as I used to. Our dispatch rate is about 98% since the latest software upgrade. In 18 months I have only seen one mechanical issue. The rest have been avionics related.

The 7X is growing on me. It may even nudge past my favorite airplane to fly, the F2000Easy.

It's all about Load 10.

It did fix a lot of stuff....maybe Load 15 will bring perfection!

:)

Actually, Load 10 fixed some problems and caused new ones. I would imagine it will take a lot more than 15 to be "perfection". :D