King Air C-90 performance?

[satpak77]

Could someone post the "real world" performance of the King Air C-90 model?

Typical cruise speed?
Range with IFR reserves?
Typical cruising altitudes? (I assume high teens/low 20s)
PAX capacity with full fuel?
Fuel burn? (up at cruise in mid-20's I get 550-650 in the B-350).

thanks guys

 

[Diesel]

I'm currently flying a B-90 Lonestar Conversion.

247kts cruise.
It loves FL250 to FL270
About 300lbs a side burn. Maybe a little less 280 or so.
No hot section or fuel nozzels and no overhaul.
Being a B-90 it's only has the lower gross weight. I think the C-90's have 10,100. I'd have to go look it up.
5 blade props make it look mean.
I'd have to look up the range we 4hrs 45 to 5.0 and your flamed out

It's a conversion plane but it's cheaper to do a conversion than buy a new one. Plus the engines only cost 68k each to overhaul after 3000hrs.

 

[Diesel]

Oh i forgot they are 750shp downrated to 550.

 

[mattpilot]

Oh i forgot they are 750shp downrated to 550.

Question:

What exactly does it mean to 'downrate' an engine? And why would you do something like that?

Or does 'downrated' just mean thats the HP at the prop (gearing loss, etc..) ?

Sorry, not engine savvy

 

[wingnutt]

well if a lonestar isnt your bag, stick with the later model C90B's. 240knots, low to mid 20's seem the place to be with about 500 an hour fuel burn. 10,100 max weight. empty runs about 6800 pounds for a well equipped aircraft. that means full fuel will leave you 800 pounds of pax capacity. subtract yourself and you get about 600 pounds available...which aint much.

 

[Diesel]

The 90 was certified for a 550shp engine. 750shp engine on it you could do some damage and it wasn't certified for 750shp.

Problem is a 550shp engine runs out of steam at around 18k. A downrated engine like 750shp allows you to hold 550shp for a lot longer. Because the engine can really do 750hp but you are just running it at 550shp you have a lot more in reserve.

So when we're running at 26k we are running a full 550shp. Also we are never temp limited on takeoff because we're only using 550shp not the full 750.

There are two lines on the torque gauge though.

 

[Diesel]

We can also do a conversion on a C-90.

The lack of a hot section is what sells the engine. Plus having the autostart feature is nice.

 

[Diesel]

A king air is a true if it fits it flies airplane. They are built like tanks.

 

[KiloBase]

Derating

De-rating on turbines is usually performed by fuel control. Only allowing the engine to produce a certain amount of power. Reason behind this is possibly to keep stress down on drive train components.

And as mentioned above. It allows the de-rated power to be held at higher altitudes without being temp limited.

 

[prpjt]

FOr a C90b the #'s are as follows.

Cruise speed - avg 235 between 17k and 21K, depends on temp. I've seen 228 and I've seen 242. It doesn't like to be heavy when it's in the 20's.


Range - 2 pax with light bags = 4:10
4 pax with light bags = 3:30
6 pax with light bags = 2:15
All times are landing with 500 lb fuel which is about an hour. IFR alternate comes
off of the above times.
This is for 210 altitude. You can go considerably longer if you go higher. My longest flight in the C90B was 4:42 at FL260.

Cruise altitudes - It likes 18K to 21K. Will go on to 260 easily if you have less than 1800 lbs of fuel.

Full Fuel Pax capacity - Our plane weighs 7100 with me and the normal stuff.
So with a full fuel load of 2573# I can carry 487 lbs of people. Weak.

Fuel burn -

FL180 = 500 pph
FL200 = 475 pph
FL220 = 440 pph
FL240 = 400 pph
FL260 = 370 pph (and 215 -220 kts)

 

[Diesel]

I've actually found that the only thing limiting us from going higher is the cabin altitude.

With the older B models the cabin has a different differential than the C's.

 

[satpak77]

ok thanks guys, good info

 

[Diesel]

Just did a flight and my fuel numbers were off.

FL260

FF 260/260 TAS 247kts.

 

[wingnutt]

so did I...

11,500 feet

ff 290/290

235 knots average (265 going south and 205 coming back)

 

[Diesel]

I've got a pic of our groundspeed doing 315 in level flight. That was a sweet day for the old girl.