I will take the pepsi challenge on runway numbers with a 550 and a 7x...

Losing only 1/3 of the power on a 3 engine plane and 1/2 the power on a 2 engine plane is not accurate. 2 engine aircraft have much more power out of each engine, thus the need for only 2. I think you'd be surprised to see actual numbers with your statement! :) Falcon 7x engine makes 6100 lbs thrust x3= 18300... x2=12200. G550 engines make 15385 each, x2=30,770. Single engine, the 550 makes more than the 7x (bigger plane, but you see the difference is about nil). Dont buy into falcon's "3 engines are safer" BS that they have been trying for years! They make a great plane, dont get me wrong! However they used to raz gulfstreams by saying "winglets are a product of poor aerodynamic design"... Now all new falcons have winglets ;)

The 550 wing is *incredibly* efficient. Able to cruise up to .89, with a normal cruise of .85 (everyday), and a typical ref speed in the very low 100's-- all with no leading edge devices. The less moving parts, the less ****** breaks! :)

-spike

While I agree with you that the "safety of three" can be bogus, depening on the airplane comparison, I can't follow your logic on amount of thrust lost in the event of an engine failure. On a three engine airplane if you lose one engine you have indeed lost one third of your thrust and on a two engine plane if you lose an engine you have lost one half of your thrust.
The question is how much PERFORMANCE has been lost by the engine failure! In your example I would agree that the GV would have the better engine out performance by far.
Although I have no data, I'm not so sure with other comparisons. B-727 vs DC-9 engine out performance comes to mind.
CG

You're failing to consider why the Gulfstream has so much more thrust than the Falcon - it weighs a LOT more so it needs the thrust!

Comparing as close to apples-apples as you can between Falcon & Gulfstream products when considering range (900EX vs. G450), the 900EX has a MTOW of 48,300lb and a OEI climb gradient of 340ft/nm. The G450 has a 73,900lb MTOW and OEI climb gradient of 285ft/nm.

Now look at the G550 vs. the 7X. G550 is 91,000lb MTOW with OEI gradient of 242 ft/nm, whereas the 7X is 69,000lb MTOW with OEI gradient of 280ft/nm. That's not really fair because the G550 has about 1000nm more range, so let's compare the G500 which has range similar to the 7X. The G500 has only 85,000lb MTOW with the same engine thrust as the G550, so its OEI gradient is 301ft/nm.

The 7X is a good performer...great runway numbers, MMO of .90, cruise at .85, LRC around .82, and refs below 110kts at light weights...

However, it really isn't in competition with a G550 or a GLEX/XRS etc. It wont fly the same distances and its simply smaller. I dont think its even marketed toward these planes? Most 7X owners are loyal Falcon buyers who like the operating cost of the 7X. Interestingly enough a 7X will currently cost you a few million more than either a GLEX or a G550.

It usually comes down to what the owner wants and the mission. Want the furthest range all the time? get a 550...want the most comfortable? get a GLEX....want the most efficient....get a Falcon.

and FWIW - all have been equally reliable and well supported from my experience, no matter what the various fanboy weirdos say...;)

Good info. My only point was its not the percentage of thrust loss, its the loss of PERFORMANCE that matters.
Having Piper Apache 150 flashback right now;)
CG

True G550 still has more power with OEI than the 7x. But might I add that you need to convert your numbers into power loading. Single engine the G550 comes in around 5.9:1 vs the 7x's 5.65:1 (Using your data). The only time I would really wish I had 3 engines would be on long flights over harsh territory, and enabling me to flight more direct routes.

To add to NowCorporate's post regarding ground servicing, the 7X has a different tow head then the other Falcons (50/900/2000) and a lot of FBOs haven't purchased them yet being that the possibility of getting an aircraft in is slim. I know my Southern California FBO gets about 1 7X a month and as I've been told by the pilots that fly in we're the only other besides LAX & SAN that have a compatible tow head.

I also personally topped off a 7X (~30,000#s) a few months back for their non-stop trans-atlantic flight. What a beautiful bird!

They carry a tow bar head stowed in the baggage area. You can also use an electric tug.

But its always easier to tell line service you dont have one so they leave you be..

;)

I've done the math before. Falcon 7X has better engine out thrust to MTOW ratio than the G550. Its 6,400 lb thrust per engine, btw, for the 7X. I agree with you that the Falcon's 3 engines aren't necessarily safer, but this isn't an opinion-based question. Some people should be able to contribute the takeoff requirements for each of the jets from their pilot manuals. I'm pretty sure that for a given range that the 7X can get to, it should be able to take off with less runway, with its advantage increasing as the runway gets higher and/or hotter.

I think that engine availability has always been a large factor in Dassault's decision to build trijets. They don't necessarily believe that trijets are always better. They have chosen to build these planes with size and performance where there weren't good business twin jet engine solutions. Once I did a little math comparing the G650 MTOW to thrust ratio with the Falcon 7X. Based on that comparison, if the Falcon 7X were to be a twin jet, it would use 11,500 lb thrust engines. These don't really exist, they're above any other business jet except for the Gulfstreams and Bombardiers based off the Rolls Royce commercial engines. Dassault probably figures that it makes more sense in this case to use 3 popular PW+C business jet engines that produce the required thrust than it does to use 2 much higher thrust engines from commercial airliner programs.

Some basic math, please correct me if it makes no sense:

Gulfstream G550 MTOW / Engine Out Thrust:

91,000 / 15,835 = 5.75 weight / thrust

Dassault Falcon 7X MTOW / Engine Out Thrust:

69,000 / 12,800 = 5.39 weight / thrust

And yes, I have heard that the Falcon 7X sells at similar-to-higher prices than the larger and longer range G550. I assumed that it had a lot to do with better runway performance, along with slightly lower operating costs.

The high prices on the 7X have nothing to do with runway numbers......its because of its operating costs and (more so) the fact that Dassault wouldn't lower the price in the recession, thus preserving initial buyers investment. This is normal for Dassault and certainly plays a part in why individual owners are so loyal to Falcons.

Glex, 550, 7X, etc..all these planes perform well on shorter runways. I have flown them all and every one is more than capable of short field, high altitude ops etc....as are most modern business jets.

Rich people care about their investments - and this can drive their decisions once the basics are met (comfort, range etc)....never seen it have anything to do with fpm/thrust ratio with one engine out and other useless hypothetical internet scenarios played out by cessna pilots.

:)