Citation question

[labbats]

I was reading the new Flying magazine that had a big article about the new CJ1+ and the CJ2+ and had a couple of questions.

It says that there is no sweep to the Citations, which I had heard before, but it went on to say that the CJ2+ was certified to Mach .737 and FL450. Doesn't the lack of a swept wing have a compressibility problem or something similar? I'm confused about this. What small understanding I have of Mach compressability is that the sweep of the wing on jets is to remove a lot of the air pushing against the wing at high speed, yet the Citation seems to contradict this.

Could anyone sum up how the Citation is able to go into the Mach .73 range without penalty to the straight wing?

Thanks in advance.

 

[Twotter76]

Not sure about the aerodynamics exactly but the Citation Ultra that I fly is certified to .755 and will get there easy enough if you are in the mid 30s. Up at 40 I doubt any of them will make it to MMO. Lear 35 has a straight wing and I think they can do .78 or so.

 

[FlyingFisherman]

The wings from the S/II all the way up to the XL/XLS are thinner than "conventional" if you consider their span. They have a flattened upper surface which delays the critical mach number (the speed at which the shock wave builds ahead of the wing as it approaches the speed of sound) hence the term "super critical" to describe the airfoil.

While the S/II, Ultra and so forth aren't as "super" as the Soverign (which has an Mmo of .80M) they are still pretty darn good at what they do.

I'm glad I didn't have to figure out the wing on the Citation X. I've been under them (on my feet off of airport property ) when they depart and the wing sweep is really something. Especially when looking at the airplane against a bright blue sky background. Just on departure they look like they're going 1000mph...to my aviation geek eyes.

 

[KeroseneSnorter]

I was reading the new Flying magazine that had a big article about the new CJ1+ and the CJ2+ and had a couple of questions.

It says that there is no sweep to the Citations, which I had heard before, but it went on to say that the CJ2+ was certified to Mach .737 and FL450. Doesn't the lack of a swept wing have a compressibility problem or something similar? I'm confused about this. What small understanding I have of Mach compressability is that the sweep of the wing on jets is to remove a lot of the air pushing against the wing at high speed, yet the Citation seems to contradict this.

Could anyone sum up how the Citation is able to go into the Mach .73 range without penalty to the straight wing?

By the way, the X-1 had straight wings and made it past mach 1.0, The F104 did mach 2.0 + with (almost) straight wings. Lots of ways around the straight wing speed issues up to a certian point.

Thanks in advance.

Thats part of the reason the CJ-2 can ONLY go mach .73.

The bravo, ultra, cj2 has plenty of power to reach much higher speeds, they are however airframe limited (wings, windshield strength etc.)

Note, EDIT screw up in the wrong place above showing in red is my comments, not part of the original posters quote...sorry for the butter fingers in editing!!

 

[FlyingFisherman]

Thx snorter, I only addressed half the issue. I went after first "how they made it get there" when engine technology lagged behind airframe development (as it always does) to now with the very well peroforming motors and a classic base airframe design.

I love this bar!:beer:

 

[Captainzero1]

The CJ1 I sometimes fly say .71. HA!