Citation X pilots....learn us your scoop

[banned username 2]

I have heard that there is a supposed "mach kit" that allows the citation X to exceed mach 1.

Is it "bull"?

That is BS...

 

[Swede]

Definitely BS in level flight. F15's and F16's will do M.9999 or so without afterburners. The drag spike that occurs in all A/C in the transonic regime is high enough to require an afterburner nudge to get through. The F22 will supercruise, that is, level supersonic without AB.

In a dive, though, it's concievable, but I wouldn't want to be in it given the weird and dangerous control surface pressures and possible flutter issues. In the late 40's, a number of aircraft came apart during diving attempts at M1.0+

Does the X have a full-flying stabilator? This is almost a prerequisite for safe supersonic flight.

 

[Vladimir Lenin]

with the level of anonymity that this board provides... I would hope that at least someone who flies an X on a regular basis would come out and enlighten us a bit on this subject

I know I pushed a 172 past the red a few times, without apparent flutter issues

 

[banned username 2]

with the level of anonymity that this board provides... I would hope that at least someone who flies an X on a regular basis would come out and enlighten us a bit on this subject

I know I pushed a 172 past the red a few times, without apparent flutter issues

I know many Falcon 10's were pushed past 1.0M in a dive by "Cowboys"...

All Falcon models were run past 1.0M during testing (except the 2000, not sure why not)... I also understand the G-V was put past 1.0M... Most jets have a full flying stab, however it is controlled only by trim, not the control yoke, but would still work...

 

[Mudworm]

Heard once while in FSI Witchita that a QS X came into the srvice center there missing an engine cowl or two. Rumor had it that the crew was doing some high speed test flying on the decent to ICT!

 

[NJA Capt]

Heard once while in FSI Witchita that a X came into the srvice center there missing an engine cowl or two.

Yes a X did lose a eng cowl in flight. One of the many things Cessna said "It can't happen" but did. The latches were all intact, and found secured and locked by the way......sans cowling.

Rumor had it that the crew was doing some high speed test flying on the decent to ICT!

1000000000% incorrect.
Unless the Cessna test pilots brought it back and decided to run a few tests themselves.


No there is not a "mach kit"
No-one I have ever heard of has/would fly over Mmo on purpose. Especially if it meant exceeding 1.0.
Yes, it passed 1.0m in testing (as FC said, the drag rise near sonic is very strong. The reference to .98 may have been for max in level flight. A descent would surely put it over mach. Other non-mach a/c that flew 1.0+....B727, Lr-25, GV)
Yes, it has a "flying horiz stab" (like any aircraft flying above .82)
Yes, it's possible to "grease it on." Though it is very technique sensitive.

 

[Vladimir Lenin]

kewl, so the consensus is that an X could do Mach 1 and its pilots would live to tell about it

 

[westwind]

Sparky Imeson, the Mountain flying guru, has some info and pictures of the X on his website.



http://www.mountainflying.com/citation_x.htm

Check out the rest of his site for tons more mountain flying info, books, videos etc.

 

[xrated]

When I went through X initial about 4 1/2 yrs ago, there was a Cessna engineer auditing the class. He was involved with the fusalage design and had some knowledge on the flight testing of the plane.

Like some have mentioned, the airplane gets VERY inefficiant at transsonic speeds....about the last .6-.7 before mach 1. As it was explanined to us, during flight test, Cessna had to prove the airplane would hold up .7 above Mmo. Hence a .92 Mmo for the X. Any higher, aka Mach 1, you are dealing with a whole nother beast. On more than one occasion....(Um lets say, In a mountain wave over the front range......ya, thats sounds good) in a mountain wave over the front range I saw .935.

Back to Initial and the Cessna engineer, when a person in class asked if it had indeed gone over Mach one, he replied, off the record, "numorous times". All of our eyes got wide, and with big grins on our faces, he quickly said that was of course in a light flight test airplane, with test pilots......so on a so forth.

Can you grease it on......you bet, about every 5th landing. Is it difficult in a cross wind? Personnaly, I thought the issue was overrated, just like any other plane you've flow a lot. You get used to it and its no big deal. The deal was at a high pitch attitude there wasn't much ground clearance at the wing tip because of the high sweep angle.

All in all, its a kick-ass plane to fly!

 

[FracCapt]

As it was explanined to us, during flight test, Cessna had to prove the airplane would hold up .7 above Mmo. Hence a .92 Mmo for the X. Any higher, aka Mach 1, you are dealing with a whole nother beast.

Part 25 requires that any new civil aircraft be test flown to "a speed at which characteristics detrimental to safe flight begin to occur", then the Mmo is designated .08 Mach below that speed, or .08 Mach below Mach 1.0, whichever is less.

 

[banned username 2]

Part 25 requires that any new civil aircraft be test flown to "a speed at which characteristics detrimental to safe flight begin to occur", then the Mmo is designated .08 Mach below that speed, or .08 Mach below Mach 1.0, whichever is less.

14 CFR 25.335 (b)(2) The minimum speed margin must be enough to provide for atmospheric variations (such as horizontal gusts, and penetration of jet streams and cold fronts) and for instrument errors and airframe production variations. These factors may be considered on a probability basis. The margin at altitude where MC is limited by compressibility effects must not less than 0.07M unless a lower margin is determined using a rational analysis that includes the effects of any automatic systems. In any case, the margin may not be reduced to less than 0.05M.

M0.92 + M0.07 = M0.99 uncorrected, if they utilize an "automatic system" (guessing Mach Trim) the margin may be reduced to M0.05.
M0.92 + M0.05 = M0.97

 

[FracCapt]

14 CFR 25.335 (b)(2) The minimum speed margin must be enough to provide for atmospheric variations (such as horizontal gusts, and penetration of jet streams and cold fronts) and for instrument errors and airframe production variations. These factors may be considered on a probability basis. The margin at altitude where MC is limited by compressibility effects must not less than 0.07M unless a lower margin is determined using a rational analysis that includes the effects of any automatic systems. In any case, the margin may not be reduced to less than 0.05M.

M0.92 + M0.07 = M0.99 uncorrected, if they utilize an "automatic system" (guessing Mach Trim) the margin may be reduced to M0.05.
M0.92 + M0.05 = M0.97

DOH! There I go again...trying to remember things...when I should really look it up to be positive before I spout off.

 

[banned username 2]

DOH! There I go again...trying to remember things...when I should really look it up to be positive before I spout off.

LOL!!! No Prob... I had to look it up myself!