Citationshares

[GVFlyer]

Re: Supersonic in the X ...

I caught a Discovery Channel special on business jets in which they rode along on a test flight in a new CX. The test pilot, when talking about how they explore the envelope for each one off the line, said "these jets will go supersonic" ... they've obviously done so in testing. But I'll bet others have as well. I would imagine you'd wanna bump the speed envelope pretty good when certifying a new design to ensure it isn't gonna instantly fall apart or become uncontrolable and unrecoverable when someone inadvertantly hits mach 1.

No one has a supersonic test point for an airplane designed for sub-sonic flight; the wing and tail and even the fuselage designs differ dramatically for flight in compressible versus non-compressible conditions.

Determing VD and MMO is determined during developmental test and is governed by FAR 25.253, FAR 25.335 and FAR 25.1505.

For most designs, flutter, a destructive-non reversible mode, determines VD and susequently MMO. In the GV, limiting speed was when rudder CLBeta went positive at about .96 mach. This is a very benign aerodynamic effect. If you are conservative you back off M.07 from this speed to determine MMO, if you're not you back off M.05. Gulfstream is very conservative hence the .885 MMO.

Every airplane is born without a Certificate of Airworthiness. Factory Production Test Pilots are authorized by the FAA to fly what is normally around a 40 page FAA approved test card to prove that each airplane meets the requirement of FAR 25 before a C of A is issued. The FAA initially flys each fifth flight with a factory pilot. As the design becomes more mature the FAA backs off to every 10th flight and the test card requirements become less stringent. For the first GV's the test card required that each jet be flown at M .955 to insure that no adverse control characteristics were present should the airplane ever get away from the pilot. The current requirement is to take each GV to M.92. Each G-IV goes to .90 to get a Cof A.

Cheers

GV













.

 

[banned username 2]

HEHEE... What a heated thread....

Thats ok, I'll race either of you guys (C-X or G-V) for a years salary!

But first we each shut down 2 engines.... DOH!

 

[bigD]

You guys are arguing all the wrong things. Only one thing really matters here.

The Citation X is a sexier looking airplane. Hands down, the thing is just gorgeous. It's like if I have a Cadillac and a Ferrari in the garage, and want to impress the ladies while out on the town - I'll roll in the Ferrari. Yeah, the Caddy is bigger and maybe better appointed, but the Ferrari is going to be the one to turn the heads.

Bottom line: if I'm cruising the country for chicks - I'll be flying the Cessna.

 

[DC8Driver]

I think I started this whole thing. All I wanted to know was how the X flies They are both beautiful Aircraft. Both do a wonderful job....and speaking of jobs......I am in need of one....any one.

As my resume sez......I will cheerfully relocate......I would gladly fly the X or the V or IV or III or II hell anyone know of a I job? Thats either brand

 

[banned username 2]

I am in the slowtation V Ultra but it seems to me I often hear on ATC -- the Falcon 2000 slowing down for Gulfstreams.

Now that does not compute according to advertised performance of these aircraft.

We often times have to slow for Gulfstreams and other jets... I believe the Gulfstream IV and Gulfstream V have a Vmo or 340 kias, our Falcon 900EX's and 50EX's have Vmo's of 370 kts...

And before GVFlyer gets his undies in a bunch, I've had to slow for a Citation X also, their Vmo is 350 kias I believe....

I'm disappointed neither of you guys have accepted my generous offer!

 

[bigD]

I'm curious - how well does the Falcon fly on just one engine?

 

[GVFlyer]

HEHEE... What a heated thread....

Thats ok, I'll race either of you guys (C-X or G-V) for a years salary!

But first we each shut down 2 engines.... DOH!

Very funeee, Falcon...

Hmmmm, Wait....Maybe if we start 250 miles from destination and I'm at 51,000 feet.......

 

[capt_zman]

BigD,

Obviously you're the one going home with the fat acne-laced chicks at the end of the night, because the X is downright ugly, both inside and out, compared with any of the Gulfstreams.

There isn't a better looking plane on earth.

 

[banned username 2]

I'm curious - how well does the Falcon fly on just one engine?

Well in the sim with the Falcon 900EX, we would do 2 engine out go arounds in Denver on a 30°C day at moderate weights.... It will climb to about 12,000 ft or so... on drift down it will come down to around 15,000 after something around 90 minutes or so (would need to look at the charts... The 900EX has a lot better performance than the 900/900B or 900C

 

[bigD]

because the X is downright ugly, both inside and out, compared with any of the Gulfstreams.

Them's fightin' words zman!

You need to put your glasses on and look again. I wonder - do you drive a Pontiac Aztek too?