King Air C-90

Thanks Wayne. The plane is so much quieter than the 58P even at 2,000, I was cruising there to begin, but have started using 1,900. I think in the past, I've pulled them back to 2,000 after climbing a bit for noise abatement and just left them there. Tom Clements has also said 1800 is also acceptable. Do I lose much efficiency there?

I'm headed to SIMCOM Tuesday and I'll check with them also.

Best,

Dave
 
Thank goodness. No more of that incessant blather about 58Ps.....

:D

Nice ride. Turbines are fun. I guess you need to be spinning 2, though, to get ATC respect. I still have to trundle around at low alts climbing out around NYC. They don't give a crap about turbine fuel burn at low altitude. :(
 
Dave, I think you will like the 1800 for cruise for noise. Actually the steeper blade angle at 1800 in cruise MIGHT be a tad more efficient but, not that you will notice. You will not give up anything. On the -61's I run, I climb at 1800 (take off is at 2000) and cruise at 1700. Makes a big difference in noise. As some have mentioned your temps are quite low. You are doing your turbine blades no favor by doing this. Your redline is what 700 deg? I suspect your blades are of similar material as most Pratts. The larger engines like tha 60's have a temp limit of 810 deg in my case. Check with Tom about this but I suspect most anybody will recommend a higher temp for cruise.
 
Thanks Ronnie: always appreciate your perspective. Yea, even at 800 pounds of torque, my TITs were only in the high 5s that day I posted. I just hate the higher fuel burn, but will give some higher power settings a try.

Dave
 
You don't feed turbines to fly cheap. If you think fuel is high just replace a set or two of PT blades due to sulfadation. Of course in my case it is not my money. Oh and BTW it is ITT, TIT makes people think you are burning avgas. Just messing with you!!!:D
 
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The slower they turn the less noise they make. The only disadvantage to 90's vs. the 200's (and it's immaterial insofar as the big picture is concerned) is that the prop tips are closer to the fuselage. But the 90's have a huge advantage insofar as running the AC on the ground without an engine running, which makes them much better suited for TX IMO.

Dave Siciliano said:
Thanks Wayne. The plane is so much quieter than the 58P even at 2,000, I was cruising there to begin, but have started using 1,900. I think in the past, I've pulled them back to 2,000 after climbing a bit for noise abatement and just left them there. Tom Clements has also said 1800 is also acceptable. Do I lose much efficiency there?

I'm headed to SIMCOM Tuesday and I'll check with them also.

Best,

Dave
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The tendency by many operators to run cool is/was partly due to a carryover from the earlier -20 engines. Those engines were quite a bit more "tender" and operators knew that some of the components (such as the guide-vane fasteners and safety wire web) were prone to break loose and wreak havoc with the PT disk and blades if they were operated at recommended temps.

Pratt redesigned the internals on -21 engines and the engines are more tolerant of what would be considered normal temp ranges for turbine engines.

So when you're getting sage advice regarding operating parameters, be sure it's from somebody who understands the generational differences.

Dave Siciliano said:
Thanks. I guess the TIT was a carry over from my 58P (g).

Dave
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Thanks. Tom Clements has done a pretty good job of reviewing that in his book which I've read a couple times. The problem is, the performance charts that came with the C90 show pretty cool temps. Tom brings out the fact that Beech didn't want the C90 to compete with the E and de-rated the -21 performance charts. When the E was no longer being sold and the C90-1 came out, the performance charts showed substantially higher power settings for the same engines.

Tom has recommended I get the C90-1 performance charts and use them. He sent a summary chart of settings at altitudes in light of ISA temps. It provides a torque setting: of course one wouldn't exceed ITT, but it doesn't show what fuel flow or IAS would be shown at those settings.

Of course, I can run the C90 book settings and compare IAS and FF to see if I'm hitting book numbers; then, run the C90-1 settings in actual use. It would just be nice to have the C90-1 performance section.

Best,

Dave
 
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Dave when you say that it burns 50gph, are you talking per side or total? If it's total, that's darn good. Even per side it's alot less than I thought it was. It was my uneducated estimation that anything with a jet engine on it burned atleast 200gph.
 
I did mean 50 gph total, but it's apparent I'm using lower power settings than what good policy would dictate for long engine life. I'll probably start flying a little higher where I can keep FF down at 60 gph or less and get better fuel economy with a higher hotter ITT
.
If you look at the panel pic I posted, FF on the left was 170 pph and on the right was near or over 200. To roughly convert to GPH divide by seven or add 50% and drop the zero at the end. So 200PPH, add 50% to 300PPH and drop the last zero would be 30 GPH on that side. The C90 looks like it will lose 6 knots if I climb to 24,000 from 18 and fuel flow drops 9%. So 3% drop in airspeed for 9% fuel savings. Makes sense to me. I'll probably start filing for 21 and 22,000 to keep the cabin under 8,000.

Dave
 
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Glad you're enjoying the new ride, Dave. It looks like your numbers are not too dissimilar to what we see on the Cheyenne II that I fly now and then. It sounds like a nice fit for you.

On the Cheyenne, we typically find that FL200-250 is a good range, depending on the winds. We went non-stop from Pennsylvania to Newfoundland back in January, burning only about 1600 lbs of fuel. About 80 kts right on the tail at FL250, and at 650 ITT burning 200 pph a side. TAS was 225, and 235 a bit lower.

It's surprised me how much I've enjoyed having GPSS and WAAS in the 310. I only spent the money on the WAAS since the lowest approach at the home field is now an LPV, and the GPSS was part of the deal with the Aspen install. I wouldn't have spent the money otherwise, but find I really enjoy having the vertical guidance on approaches, and setting the autopilot in GPSS mode and letting it follow the routings. Definitely spoiled me.

flyersfan31 said:
Nice ride. Turbines are fun. I guess you need to be spinning 2, though, to get ATC respect. I still have to trundle around at low alts climbing out around NYC. They don't give a crap about turbine fuel burn at low altitude. :(
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They don't typically care even if you have two around NYC. One of the disadvantages of living there.

DavidWhite said:
Dave when you say that it burns 50gph, are you talking per side or total? If it's total, that's darn good. Even per side it's alot less than I thought it was. It was my uneducated estimation that anything with a jet engine on it burned atleast 200gph.
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Your uneducated estimation is, indeed uneducated. 50 gph combined is very low for a turbine twin. However, in the Cheyenne we're typically doing about 60-70 (which is probably what Dave will end up seeing if he starts running his engines a bit harder), and in the Commander we see about 70-75. Both are far, far away from 200 gph.
 
Dave Siciliano said:
I did mean 50 gph total, but it's apparent I'm using lower power settings than what good policy would dictate for long engine life. I'll probably start flying a little higher where I can keep FF down at 60 gph or less and get better fuel economy with a higher hotter ITT
.
If you look at he panel pic I posted, FF on the left was 170 pph and on the right was near or over 200. To roughly convert to GPH divide by seven or add 50% and drop the zero at the end. So 200PPH, add 50% to 300PPH and drop the last zero would be 30 GPH on that side. The C90 looks like it will lose 6 knots if I climb to 24,000 from 18 and fuel flow drops 9%. So 3% drop in airspeed for 9% fuel savings. Makes sense to me. I'll probably start filing for 21 and 22,000 to keep the cabin under 8,000.

Dave
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Thanks for the info Dave - I've been enjoying reading this thread. It's not only very informative, but it's also stinkin' cool that you own a KA!
 
DavidWhite said:
Thanks for the info Dave - I've been enjoying reading this thread. It's not only very informative, but it's also stinkin' cool that you own a KA!
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It's only a natural progression - now he's always running LOP! ;)
 
DavidWhite said:
Thanks for the info Dave - I've been enjoying reading this thread. It's not only very informative, but it's also stinkin' cool that you own a KA!
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Yes, one of my many vices :rofl:

Thank goodness for this and other boards where I can confess my sins to folks with a sympathetic ear. Once one has the flying bug, it's just a matter of degrees!

Best,

Dave
 
I see the listing on Controller doesn't show the plane anymore. Here's a pic on the ramp in Rockford and an interior shot when I was in Oshkosh with my niece and her family.

Best,

Dave
 

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Dave Siciliano said:
I see the listing on Controller doesn't show the plane anymore. Here's a pic on the ramp in Rockford and an interior shot when I was in Oshkosh with my niece and her family.

Best,

Dave
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Sweet.

Are there more than 4 passenger seats?
 
Dave Siciliano said:
Yes, one of my many vices :rofl:

Thank goodness for this and other boards where I can confess my sins to folks with a sympathetic ear. Once one has the flying bug, it's just a matter of degrees!

Best,

Dave
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The only thing worse than the flying bug..................is the TURBINE flying bug!!!! :yikes::yikes: Once you start burning Jet-A it's hard to go back to avgas, real hard.:mad2: But it's doable. :D
 
45 hours in the last month seeing:
300 gph climb
220 gph cruise
but somebody else is paying :D

Dave, your plane looks GREAT!
 
Lance F said:
45 hours in the last month seeing:
300 gph climb
220 gph cruise
but somebody else is paying :D

Dave, your plane looks GREAT!
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Hope to see you at Gaston's Lance.

Dont know John, but I can certainly understand that.

Dave
 
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Dave Siciliano said:
Thanks Ronnie: always appreciate your perspective. Yea, even at 800 pounds of torque, my TITs were only in the high 5s that day I posted. I just hate the higher fuel burn, but will give some higher power settings a try.

Dave
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I would think you should be able to raise the temp and torque by reducing RPM without increasing fuel flow.
 
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Thanks Henning. I'll try 1900 and a bit higher and see where that gets me.

Here's a pic from front to back. Behind the seat to the left is a side facing, belted seat. You can see the seat in the rear and their is a set of curtains in front of it that can be closed for privacy. Luggage is stored in the cabin to the left of that rearmost seat.

As I talk through this, it reaffirms more reasons I liked this particular plane: nice interior and I liked this layout--many C90s didn't have this configuration, or had a raggy interior. The avionics were better than most of this vintage, decent paint; good maintenance history and I knew everyone (or had friends in common in the case of the seller) and didn't have to go through what can sometimes be a challenging purchase negotiation.


Dave
 

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wabower said:
The Pratt & Whitney hot-section repair guys at Dallas Airmotive (at Love Field if you ever want to stop in and see their operation) say they see more blade damage from sulfidation than from running too hot. Max continuous for the -42 in our B-200 was 770C, they recommended at least 760. Max allowable is 800C.
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I'm no expert on turbine ops but this came from one:

A common myth is that changing engine operating temperatures can alleviate sulfidation problems. The truth is that changing engine operating temperatures only moves the location within the turbine area where sulfidation occurs. Lowering operating temperatures moves the sulfidation to the CT vane ring, whereas increasing the operating temperatures moves the sulfidation to the CT shroud segments and the power turbine vane ring. For this reason, flight crews are not encouraged to make any changes in the operating regime of the aircraft to decrease sulfidation. However, they should be aware that periods of high temperature during start-up, and high temperature/high power conditions during take-off and cruise all contribute to “premature hot engine distress.”
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There are (or were) a number of CT blades in the top right desk drawer of the spare desk at your shop that will refute that statement. All were condemned due to sulfidation.

gismo said:
I'm no expert on turbine ops but this came from one:
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Dave Siciliano said:
Does anyone have a reference for checking the indicated airspeed indicator in the air? As I recall, one ran a triangle of a known distance with the GPS and compared the three legs. Can anyone point me to a good explanation of how to properly perform it?

Thanks, Dave
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There are several methods but all involve capturing enough data to determine the wind vector and compensating for that directly or indirectly.

One method require measuring the groundspeed while flying three headings 90° apart, another (my preference) has you record the GPS track and GS on three divergent legs, some use four legs. AFaIK, any method that simply averages the GS on three or more legs will only provide an approximation because the effects of the wind are not associative.

There are also many spreadsheet examples and Java applets that can be downloaded on the web to perform the calculation (all of which involve solving three or four simultaneous equations). I think there might even be an iPhone app for this.

This page on the RV-8 forum has links to several such apps:

http://go.phpwebhosting.com/~khorton/rv8/phplinks/index.php?PID=49

All the methods I've seen yield TAS so to calibrate your indicated airspeed you will need an accurate OAT (or TAT if you're going fast) and pressure altitude to translate the TAS back to IAS correctly. And watch out for the many IAS/TAS "calculators" which use a simple formula that assumes a linear relationship between the ration of IAS to TAS and altitude as that is likely to be off by at least a few knots.

I prefer the methods which use GPS track vs the ones using magnetic heading because small errors in the measured magnetic heading can generate large errors in the computed TAS if the wind is strong and GPS tracks are far more accurate than headings.
 
Dave Siciliano said:
Thanks Henning. I'll try 1900 and a bit higher and see where that gets me.

Here's a pic from front to back. Behind the seat to the left is a side facing, belted seat. You can see the seat in the rear and their is a set of curtains in front of it that can be closed for privacy. Luggage is stored in the cabin to the left of that rearmost seat.

As I talk through this, it reaffirms more reasons I liked this particular plane: nice interior and I liked this layout--many C90s didn't have this configuration, or had a raggy interior. The avionics were better than most of this vintage, decent paint; good maintenance history and I knew everyone (or had friends in common in the case of the seller) and didn't have to go through what can sometimes be a challenging purchase negotiation.


Dave
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Pretty sweet plane there Dave, give a shout next time you're in So Fla, I'd love to take a look.:D

Thing to remember about turbines is they are "LOP" engines, the only time a turbine is "ROP" is on start up, and we all know what happens when they get too rich.:hairraise:

If you keep the fuel flow the same as you reduce RPM you enrichen the mix since you reduce the airflow/time. It basically will have the same effect as if you are flying 30*LOP and richen it up to 5* LOP, you'll increase temperature and combustion pressure which will increase torque.
 
Fuel control units handle all the mixture issues. Pilot has no input.
Henning said:
Pretty sweet plane there Dave, give a shout next time you're in So Fla, I'd love to take a look.:D

Thing to remember about turbines is they are "LOP" engines, the only time a turbine is "ROP" is on start up, and we all know what happens when they get too rich.:hairraise:

If you keep the fuel flow the same as you reduce RPM you enrichen the mix since you reduce the airflow/time. It basically will have the same effect as if you are flying 30*LOP and richen it up to 5* LOP, you'll increase temperature and combustion pressure which will increase torque.
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Thanks Lance. I'll try to look at those. Any chance you'll be at Gaston's this year?

I don't really have a manner in which to lean the condition lever on here Henning: just low and high idle best I can tell. And, if I could lean, I'd have to idea what to look at when I did to be safe.

Best,

Dave
 
I have nothing useful to add to the conversation about operating turbine engines, but I've enjoyed reading this thread - very informative and a good read for us 'little' bug-smasher peons.

Now if you will excuse me, I need to get a towel to wipe the drool from the keyboard after seeing the pic of Dave's KA. ;)
 
Dave Siciliano said:
I don't really have a manner in which to lean the condition lever on here Henning: just low and high idle best I can tell. And, if I could lean, I'd have to idea what to look at when I did to be safe.
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I recall when I was learning how to fly the King Air, someone pointed to the condition levers and said, "Remember, these are not mixture."
 
I dont believe Henning is saying you directly adjust the mixture just that the net effect of changing RPM / power results in such. Since I know nothing about turbines I cant say much.
 
wabower said:
Why do you think PT-6 is rich at startup?
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That little puff that comes out the pipe, if you have visible exhaust you have unburned fuel. Sorry, I didn't mean the entire starting process just that first moment. However if you get a "hot start" you are definitely rich.
 
Well, I'll probably step all over my feet with golf shoes, but we have three main engine controls: the power levers on the left is what we advance to bring up torque/n1; the prop controls and the condition levers. The condition levers are set to high or low idle. I normally just adjust those in conditions where I what the engine idling at a high power setting; like on start when I need more power to the generator, or a short field landing where I want full beta to stop after the mains touch. I don't normally adjust the condition levers at all in normal flight.

I've only got a bit over 40 hours in this plane now, so, I'm still learning a lot, but I have some great coaches in Wayne, Tom Clements, my mechanic and Joe Sasser here that has about 5,000 KA hours and ran Kerr McGee's flight department. (Several other volunteers offering to fly with me and provide free advise (g)).

Best,

Dave
 
CJones said:
I have nothing useful to add to the conversation about operating turbine engines, but I've enjoyed reading this thread - very informative and a good read for us 'little' bug-smasher peons.

Now if you will excuse me, I need to get a towel to wipe the drool from the keyboard after seeing the pic of Dave's KA. ;)
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I haven't seen anything in POA rules about you having to add anything useful to be on here :rofl: Most of what I post is probably not in the useful category. We enjoy you're company; I'm just more right brained than most folks.

Best,

Dave
 
jesse said:
I dont believe Henning is saying you directly adjust the mixture just that the net effect of changing RPM / power results in such. Since I know nothing about turbines I cant say much.
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We can change that at Gaston's sir!

Best,

Dave
 
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