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JammedStab
13th Apr 2018, 05:14
Really...did they have that much drag?

Just reading an article about the Cirrus Vision Jet and the writer says that for the descent, he pushed the thrust up to max continuous because like the Citation 500, aerodynamic drag prevents the aircraft from exceeding redline speeds in 3-500 fpm descents at MCT.

eckhard
13th Apr 2018, 10:37
All the straight-wing Citations are draggy in the descent, the 500 series more so than the the 525s.

Cruising at any level above about FL280 was normally accomplished with full thrust. Any climb required a reduction in speed to achieve.

Assuming a C550, here are some typical figures:

Cruise at FL370. N1 102%. IAS 190. TAS 360. M0.62

At top of descent, you could push over to achieve about 1000fpm and the airspeed would increase but so would the barber’s pole. If you wanted 2000fpm you would reduce N1 to about 85%.

Eventually the Vmo would be about 260 and your IAS about 240-250.

In the event of an emergency descent, with thrust levers closed and speedbrakes out, descent rates must have been 5000-6000 fpm, but I can’t really remember.

I do remember when I moved from Citations to B737, being astonished that one could cruise at 85% N1 and have sufficient excess thrust available that one could maintain speed if one climbed to a higher cruise level.

At top of descent the thrust levers were closed! Just shows the huge difference made by a swept wing.

Tinstaafl
14th Apr 2018, 05:39
I fly a C500. For most descents I leave power near cruise setting, with slight reductions in lower altitudes to stay under Vmo. Depends on the ROD I choose, but I typically aim for 1000-1500'/min. Any more and the pressurisation in the one I fly can misbehave.

Above The Clouds
16th Apr 2018, 14:54
I heard the Citation 500 was so slow that its one of the few jets that could have a bird strike from behind :)

flyboyike
16th Apr 2018, 16:40
I heard the Citation 500 was so slow that its one of the few jets that could have a bird strike from behind :)

Not only that, there is an option for trailing edge deicing.

His dudeness
16th Apr 2018, 17:37
At top of descent the thrust levers were closed! Just shows the huge difference made by a swept wing.

Do that in a Sovereign and you`ll stall at a 1000fpm.... with 16° swept on the wings...

Doin 174 KIAS at 3nm on a 3° GP, close the throttles and deploy full flap, youŽll make a crater at one mile final.

Them dudes at Cessnas do know how to build some drag into their flying contraptions...

Guptar
11th May 2018, 05:17
Would the CJ4 be classed as draggy.

Do the Tamarak winglets take out a lot of that descent drag?