Range + ETOPS of a Citation X

[banned username 2]

Hey Sheik,

I have heard that about the straight 50's... Does the straight 50 have a different fuel system? You said you depart with the center tank empty? On the 50EX we have 3 "wing tanks" and 3 feeder tanks... each wing tank feeds it's respective feeder which feeds its respective engine... If we depart with the "center" tank empty, ol' #2 is just along for the ride....

Yeterday we departed from near Boston with 9,500 lbs. of fuel and 4 pax on board, climbed directly to FL430 and cruised at Mach 0.83 all the way to Chicago... Temp at altitude was ISA, time to climb to 430 was about 18 mins...

They advertise the 50EX range as 3,220 NM.... my guess is it is closer to 3,000 NM.... I have gone 7 hours and still landed with 2,800 lbs on board....

 

[Sheik_Yer_Booty]

From you description of the 50EX, the fuel system is the same; 3 wing and 3 aft fuse tanks. Each fuse tanks is fed via a transfer pump from its associated wing tank then the engine is fed via the boost from its associated fuse tank.

I just referred to the tank layout as a single tank only because it has a single quantity gauge indicator for all three-fuselage tanks, misstatement on my part. We won’t run the center tank dry for the reasons you point out but we don’t depart with it fully fueled either. Only when we are tankering fuel, which is rare.

18 minutes to 430… good grief…

At 33,000 lbs it would take us 18 minutes to reach FL310 on a good day, 27 minutes to FL390 and nearly 35 to FL430.

 

[banned username 2]

OK, I understand now... we have 3 gauges for the 3 wing tanks and 3 gauges for the 3 feeder tanks....

I have never flown the straight 50 but have been told the 50EX has a ton more performance than the straight 50...

I fly the 900EX also, I understand it has quite a bit more performance than the 900B... The EX series of Falcons seem to be what the originals SHOULD have been, but I guess the airframe was before the engines time!

The Falcons are certainly the best hand flying plane out there... like driving a BMW... smooth and responsive!

Arthur Q is my best friend!

 

[h25b]

Thanks for the insight, sounds to me like the straight 50 is pretty much a loser, glad we didn't get it. I don't see much advantage to the straight 50 other than maybe the range. One other question, what additional maintenance issues are there with the #2 engine. Seems like it would be a royal pain to get to. Do to its position are there issues. I fly the 731 on the Hawker 800's and we've recently had some engines popping bybass buttons and having to get torn down. I wouldn't want to go through that very often with that #2.

Anyway just thinking out loud, without really having a clue what I talking about.

 

[banned username 2]

The cowl on the #2 engine is a big clam-shell which opens on the bottom of the engine... very easy access... out mechanics never complain about #2 at all...

The straight 50 is still a very good machine... still will second segment outclimb (OEI) any 2 engine plane... but the 50EX has a lot more performance and a full glass cockpit...

 

[GVFlyer]

Dassault

You know that Serge' Dassault tried to put the 50 out of production, but it had such a loyal customer base that the customers wouldn't let him, hince the 50EX. Falcon has had their share of problems with the TFE 731's. The 900 initially had problems with reduction gearing causing resonance and fan cracks. Then there were the problems with the carbon seals which they fixed, but then forgot to fix on the -40 and -60 engines for the 50EX and the 900EX. However, they had bigger problems on those engines in that the number 4 bearing journals were improperly drilled so they were not oiling properly. Subsequently, all the cases had to be cracked to fix the problem. Statistically, you are still more likely to arrive single engine in a three-holer Falcon than you are in the the Rolls-Royce powered Gulfstream. If three engine aircraft were a good idea, somebody besides Dassault would make them. There is an immediate 50% increase in maintenance costs when you have three engines doing the work of two. Falcon has realized this, their newest product will have two engines.

Having said all this, I've long thought that the Falcon was a great airplane in search of a great engine - they sure are sweet to fly!





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[banned username 2]

Actually the 50EX has -40 engines and the 900EX has -60 engines...

I think statistically you are more likely to end up "Single Engine" in a two engine airplane, because in a 3 engine airplane it would require a double engine failure...

I THINK what you meant is statistically you are more likely to loose an engine in a 3 engine plane than a 2 engine plane... but then again, no big deal, a single engine failure isn't even on the Emergency Checklist... it is on the Abnormal Checklist!

And by the way, their "Newest Product" will have THREE engines... the Falcon 7X.... looks like a very overgrown 900EX, but with greater sweep angle on the wings... but still 3 engines!

 

[GVFlyer]

Granted.

I meant that because the Allied Signal TFE-731's fail at a rate greater than twice as often as the Rolls Royce's that you are statistically more likely to loose two of the TFE-731's than you are one of the Rolls.

This is easy to understand. At mid-ocean, the BR-710's on the GV are running around 88-89% on both LP and HP. The fastest spool on the engine is turning around 11,000 rpm. The engine is derated to 14,750 pounds of thrust from a family of engines designed to produce 22,000 lbs. It's loafing.

The TFE-731 engine started life as an APU for the DC-10. It has had to grow significantly since it's original design. In most applications, it's trimmed up to 101.5% and it's fastest spool is spinning at over 40,000 rpm. Keep in mind that internal pressures are a squared function of rotational velocities. It's running hard.

The newest product I was referring to is the 2000EX which has flown and will be delivered with two PW308C's once certified. It's interesting to note that they have abandoned the GE 738's in this growth derivative of the 2000.

It will be interesting to see if Dassault makes the Falcon 7X. I hope they do - competition improves the breed, but they have backed out of this market once before.