Why do Dassaults have 3 engines?
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We purchased a 900EX after a great amount of research between the G-IVSP and the 900EX. We conducted a fly-offs between the two aircraft on trips that fit our trip profile. The fly-off were to see which aircraft could perform the following legs non-stop.
Oklahoma City-London/London-Oklahoma City. (Both aircraft could do this leg.)
Aspen-London. (Only the 900EX could do this leg and only when the OAT was -05 c. with good weather at Aspen. The G-IVSP could not do this leg no matter how cold the OAT was in Aspen.)
Aspen-Bogotá Colombia. (Both aircraft could do this leg, however, in the summer when the OAT was above, I believe 15c, the G-IV was unable to go non-stop.)
Plus a few others that both aircarft could do non-stop.
As the owner lived for the most part in Aspen and secondly in London, the non-stop Aspen-London leg was the most important to him. The only other two aircraft at the time that could go Aspen-London non-stop were the Global Express and the G-V, both of which were out of our price range. Therefore we chose the 900EX.
As for cabin size comparison it may interest you to know that the 900 has more space in the 'living' or passenger cabin area than the G-IVSP. This area excludes the galley and the aft lav. A small point and a small amount of square footage I'll admit. The size of the galley in the 900EX never caused us any problems.
One more point that was important to me and the other pilots was that loading baggage into the baggage compartment was a hell of a lot easier on our backs with the 900 verus the G-IV. A small thing admittedly and not something the passengers don't really care about, but was never the less a factor.
Other point, going across the Pacific Ocean having three engines, compared to the two, was a nice comfort factor to me at least.
Another point is that 900 was much lighter on the controls that the G-IV. The G-IV reminded me more of a 727, where the 900 flew more like a Sabre 40 or a Lockheed Jet Star.
However, in summation, I would have been just happy flying the G-IVSP if that been the aircraft the boss chose to buy. Both aircraft are great and again I would been happy flying either one.
Oklahoma City-London/London-Oklahoma City. (Both aircraft could do this leg.)
Aspen-London. (Only the 900EX could do this leg and only when the OAT was -05 c. with good weather at Aspen. The G-IVSP could not do this leg no matter how cold the OAT was in Aspen.)
Aspen-Bogotá Colombia. (Both aircraft could do this leg, however, in the summer when the OAT was above, I believe 15c, the G-IV was unable to go non-stop.)
Plus a few others that both aircarft could do non-stop.
As the owner lived for the most part in Aspen and secondly in London, the non-stop Aspen-London leg was the most important to him. The only other two aircraft at the time that could go Aspen-London non-stop were the Global Express and the G-V, both of which were out of our price range. Therefore we chose the 900EX.
As for cabin size comparison it may interest you to know that the 900 has more space in the 'living' or passenger cabin area than the G-IVSP. This area excludes the galley and the aft lav. A small point and a small amount of square footage I'll admit. The size of the galley in the 900EX never caused us any problems.
One more point that was important to me and the other pilots was that loading baggage into the baggage compartment was a hell of a lot easier on our backs with the 900 verus the G-IV. A small thing admittedly and not something the passengers don't really care about, but was never the less a factor.
Other point, going across the Pacific Ocean having three engines, compared to the two, was a nice comfort factor to me at least.
Another point is that 900 was much lighter on the controls that the G-IV. The G-IV reminded me more of a 727, where the 900 flew more like a Sabre 40 or a Lockheed Jet Star.
However, in summation, I would have been just happy flying the G-IVSP if that been the aircraft the boss chose to buy. Both aircraft are great and again I would been happy flying either one.
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Existfirstright,
I may have to dispute some of your 'facts'!
Not sure about the 7X engines, but the 900 engines which you say have no airline history is somewhat incorrect. The Honeywell engines on the Lear 45 and Falcon 900 are in fact the core units from the McDonnell Douglas DC10/MD11 APU's. I know APU's don't have to be as reliable as the primary powerplants, but the BAe 146 and Chinook and others seem to manage OK!!
I'm no expert on Gulfstream's or Bombardier products, but the 900 does have two completely independent hydraulic systems with four hydraulic pumps..... how many other bizjets have four independent pumps?
I may have to dispute some of your 'facts'!
Not sure about the 7X engines, but the 900 engines which you say have no airline history is somewhat incorrect. The Honeywell engines on the Lear 45 and Falcon 900 are in fact the core units from the McDonnell Douglas DC10/MD11 APU's. I know APU's don't have to be as reliable as the primary powerplants, but the BAe 146 and Chinook and others seem to manage OK!!
I'm no expert on Gulfstream's or Bombardier products, but the 900 does have two completely independent hydraulic systems with four hydraulic pumps..... how many other bizjets have four independent pumps?
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At the same time, given the close proximity of the 3 engines, I'm not that convinced by the safety argument.
It's nice if one of the engines goes down (no fuel
?), but if it's an uncontained failure, it would probably have been better to have just one engine, but on the other wing...no ?
Nice plane though.
It's nice if one of the engines goes down (no fuel
?), but if it's an uncontained failure, it would probably have been better to have just one engine, but on the other wing...no ?Nice plane though.
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Chinook and others seem to manage OK!!
Also, that engine had two major flaws which wouldnt necessarily show themselves in APU application - Rollback, and bleed air contamination.
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Well, an uncontained failure between engines one and three on the 900 are no different than any other pylon mounted twin engined jets, with any failure debris having to puncture through the fuselage to get to the other side.
Most people don't realise that the centre engine on the 900 and 7X is mounted well aft of the other two. There is a large 'S' duct and nacelle entrance is not where the mid engine is mounted!!!!
Certainly the BAe 146 has had its fair share of contaminated air issues, but the DC10 APU was/could be used in flight to assist pressurization and bleed air to the cabin, so not sure there's much mileage in that argument?
Most people don't realise that the centre engine on the 900 and 7X is mounted well aft of the other two. There is a large 'S' duct and nacelle entrance is not where the mid engine is mounted!!!!
Certainly the BAe 146 has had its fair share of contaminated air issues, but the DC10 APU was/could be used in flight to assist pressurization and bleed air to the cabin, so not sure there's much mileage in that argument?
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I'm not an expert on the subject, but I believe the contamination issues only arose when the engine was used as such, and not as an APU. There are some significant differences in extracting air from an APU versus an engine, plus of course, the exposure to engine air lasts a lot longer.
Rollback was an issue above F260 - not a factor thats going to become apparent as an APU!
Rollback was an issue above F260 - not a factor thats going to become apparent as an APU!
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The bigger issue in respect of the Honeywell engines in the 900EX and EASy's that I've flown, is the issue of engine runaway...and I believe a lear was "parked" into a hangar at some point thanks to this.
Never heard of the bleed air issue before, so thats a new one on me.
Lastly, the Falcon has 3 levels of redundancy when it comes to flight controls, 2 independant hydraulic systems, and manual reversion...a bit like a 737.
Never heard of the bleed air issue before, so thats a new one on me.
Lastly, the Falcon has 3 levels of redundancy when it comes to flight controls, 2 independant hydraulic systems, and manual reversion...a bit like a 737.
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Well ditto, I'm no expert on this either, but I don't see why there is a difference in extracting bleed air from an engine just because its being used as primary power rather than auxiliary?
Which aircraft fitted with these engines suffered from 'rollback' issues then? I've certainly never heard of these major flaws you refer to!
There is certainly more protection from this with FADEC/DEEC when used as primary sources of power.
Which aircraft fitted with these engines suffered from 'rollback' issues then? I've certainly never heard of these major flaws you refer to!
There is certainly more protection from this with FADEC/DEEC when used as primary sources of power.
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4000' runway in a GV is suicide??
I used to operate a GV out of EGTK, Oxford, England. Its about 4300'. Hardly even touched the brakes on that runway.
I think you have mixed the numbers for a G4 in there. 4000' would be tight for the 4, yet doable.
The Vref for a G5 is much lower than 129 at typical landing weights. I seem to recall 108.
I think you have mixed the numbers for a G4 in there. 4000' would be tight for the 4, yet doable.
The Vref for a G5 is much lower than 129 at typical landing weights. I seem to recall 108.
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Please lets keep it sensible!! APU's are now powerplants, I dont think so.
As for the 146 well they had four engines and struggled to keep them all going. Three & Spare I recall my mate saying after flying one in Oz.
Falcon must be loving you for saying they have 3 x APU engines driving their fine aircraft. Also the Chinook came in for grief as the engines were - yes - unrelaibale! They are the engines in the original 146 - Lycoming ALF somethings... now there was a successful program, it nearly broke BAE.
As for the runway the Global needs 4139ft at ISA SL vs 5150ft for the 900EX for a 3,700nm mission.
Systems - I defy anyone to fly manual reversion at FL450.The Falcon has Dual Primary Flight Control Systems plus man. rev while the Global has three primary hydraulic. It also has 7 hydraulc pumps vs 4 on the 900 and 6 electrical vs 4.
One minor point while researching this topic the Flaocns range quote is at M.80 against M.85 for the Global.
The Global is simply more airplane and of course costs more money, there is mush more real estate down the back,
As for the 146 well they had four engines and struggled to keep them all going. Three & Spare I recall my mate saying after flying one in Oz.
Falcon must be loving you for saying they have 3 x APU engines driving their fine aircraft. Also the Chinook came in for grief as the engines were - yes - unrelaibale! They are the engines in the original 146 - Lycoming ALF somethings... now there was a successful program, it nearly broke BAE.
As for the runway the Global needs 4139ft at ISA SL vs 5150ft for the 900EX for a 3,700nm mission.
Systems - I defy anyone to fly manual reversion at FL450.The Falcon has Dual Primary Flight Control Systems plus man. rev while the Global has three primary hydraulic. It also has 7 hydraulc pumps vs 4 on the 900 and 6 electrical vs 4.
One minor point while researching this topic the Flaocns range quote is at M.80 against M.85 for the Global.
The Global is simply more airplane and of course costs more money, there is mush more real estate down the back,
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Comparing a Global to a 900 is daft, two different machines completely, and each wonderful in thier own way. Anyone that wants to knock the Falcons obviously has not flown them.
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Hey, CON-PILOT I honestly hope you are talking about London (Canada) not UK. .. First ...
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Systems - I defy anyone to fly manual reversion at FL450.The Falcon has Dual Primary Flight Control Systems plus man. rev while the Global has three primary hydraulic. It also has 7 hydraulc pumps vs 4 on the 900 and 6 electrical vs 4.
First of all, why would you be at FL450 in a 900EX as in most configs you would struggle to get there unless you were on fumes, and secondly, why would you consider staying up there with two hydraulic systems failed?
I'm afraid your comparison is totally nefarious, 2 totally different aircraft for two completely different missions.
I'd love to see a GLEX get in and out of LCY for example, and then trott off to DXB.
You can happily fly at .85 all day long, trouble is your passenger will still arrive in DXB 30 minutes after the Falcon as they are going to have to get to LTN or STN...and thats going to take a minimum of 40 minutes.
2 very different aeroplanes with 2 different missions period.
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Hey, CON-PILOT I honestly hope you are talking about London (Canada) not UK
As for the 900EX/EASY cruising at FL450, it not a big deal. Admittedly one cannot go straight to 450 just after a maxi mun gross weight takeoff, however, you certainly can after cruising for a few hours at lower flight levels.
Same with the 50EX.
As someone already posted, you cannot compare the G-V or the Global Express to the 900EX/EASY. The G-IVSP, or whatever it is called now and the 900EX/EASY, yes.
Now as for DOC hourly cost between the G-IVSP and the 900EX/EASY, the 900 is lower due to the lower fuel burn on the 900, however, the difference is not that much. If I recall correctly it would take about ten years to see a real savings. One other minor point is that the 900 has lower airport usage fees because it is lighter than the G-IV/whatever.
As I previously posted, both aircraft are great and I would have been happy flying either one.
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Wow I never imagined that this thread was going to be this enduring when I created it.
While the debate between the Falcon 900 and GIV is interesting, I think that they are two different planes designed at different times and with different philosophies and goals...
I'm wondering if any of the newer participants have insight towards my original question:
"Thinking theoretically/abstractly, what are the tradeoffs is performance characteristics between 2 and 3 turbine aircraft?"
For example, we all know that given the same level of technology, 2 engines are able to produce X pounds of thrust more efficiently than 3 smaller engines could. However, since airplanes only have to be able to complete their takeoff with one engine out, the 3 three engine plane needs less total thrust to operate, ceteris paribus. So which design choice (2 vs 3 engines) is fundamentally more efficient?
While the debate between the Falcon 900 and GIV is interesting, I think that they are two different planes designed at different times and with different philosophies and goals...
I'm wondering if any of the newer participants have insight towards my original question:
"Thinking theoretically/abstractly, what are the tradeoffs is performance characteristics between 2 and 3 turbine aircraft?"
For example, we all know that given the same level of technology, 2 engines are able to produce X pounds of thrust more efficiently than 3 smaller engines could. However, since airplanes only have to be able to complete their takeoff with one engine out, the 3 three engine plane needs less total thrust to operate, ceteris paribus. So which design choice (2 vs 3 engines) is fundamentally more efficient?
If 2 engines weren't more efficient, the B777 wouldn't be the most popular plane for int'l airlines. There are no 3-engine airliners anymore and the A380 is certainly the last 4-engine design we'll see.
Dassault tried to claim that 2 was for "domestic" use and 3 was for overwater--worked until DA2000 customers wanted more range to go overwater.
GF
Dassault tried to claim that 2 was for "domestic" use and 3 was for overwater--worked until DA2000 customers wanted more range to go overwater.
GF
falconeasydriver
While the GLEX is not yet cert'd for LCY, I just ran a runway analysis and flight plan, LCY-DXB and it could do it, with NBAA reserves. Max TOGW today, dry runway was 81,000 lbs--straight climb to FL 430, step at 470 around Damascus
GF
While the GLEX is not yet cert'd for LCY, I just ran a runway analysis and flight plan, LCY-DXB and it could do it, with NBAA reserves. Max TOGW today, dry runway was 81,000 lbs--straight climb to FL 430, step at 470 around Damascus
GF
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I only throw spanners at the things but does the 900 not have a greater range than the 2000 Galaxy flyer?
Also in defence of the TFE731 its been around in various formats for atleast 25yrs......Its a very reliable engine.
Garrett TFE731 - Wikipedia, the free encyclopedia
Also in defence of the TFE731 its been around in various formats for atleast 25yrs......Its a very reliable engine.
Garrett TFE731 - Wikipedia, the free encyclopedia
Last edited by spannerbearer; 17th Feb 2010 at 06:01. Reason: TFE731 ref added