King Air C-90

Nothing to it and you would never know. Engineers say it could easily fly to 60k but no reason to do so and certification would be difficult. All Gulfstreams are notoriously over-powered, so engines are usually in loaf mode. I've never used FL510 as an alititude, only came close (above 50k)once when topping a storm enroute from LAX to some outlying airport in Detroit.

Henning said:
Ok, that's where 9 some came from, I was not aware they certified that altitude, that's pretty interesting, I would love to get a ride through that altitude cycle so I could watch that engine performance cycle. That's running pretty close to the ragged edge.
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Dave Siciliano said:
Ted: 4.6. At 20,000 our cabin is 7,000. We are seeing exactly what the gauge shows it should be. 230 was 9000. That seems to be the tradeoff, better fuel flow and range higher, better cabin and a bit faster lower. We were also topping some weather which made 230 the best choice.

Dave
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Thanks for the info, good food for thought!

The Commander has a 5.4 psid cabin, IIRC. We end up flying it at FL260-270 typically, because of the fuel economy. Of course, that gets us up at the 10,000 ft cabin pressure. A bit higher than is really nice, but seems to work.
 
What's more amazing to me are the old Lear 24E/F and 25D/F that were certified to FL510. The few 24 and 25 s I got to fly were only good to FL450. I really wanted one time to get one that was certified to 510 and take it up there just long enough to take a couple of pictures. I think I would have worn a mask :yesnod:
 
wabower said:
Nothing to it and you would never know. Engineers say it could easily fly to 60k but no reason to do so and certification would be difficult. All Gulfstreams are notoriously over-powered, so engines are usually in loaf mode. I've never used FL510 as an alititude, only came close (above 50k)once when topping a storm enroute from LAX to some outlying airport in Detroit.
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51,000 you should be starting to get a black sky above and seeing the curvature of the Earth. If I had one I'd have to go at least once as high as it could go just to get some pictures.:yesnod:
 
I've flown many trips at 490 and didn't see much difference. Couldn't tell if the houses looked any smaller.

Henning said:
51,000 you should be starting to get a black sky above and seeing the curvature of the Earth. If I had one I'd have to go at least once as high as it could go just to get some pictures.:yesnod:
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wabower said:
Do the houses look any smaller from there?
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I doubt it, regardless that's not the direction I'd be looking if I could get to 60,000'. That would be an awesome view, and yes, the houses will disappear there.
 
Henning said:
I doubt it, regardless that's not the direction I'd be looking if I could get to 60,000'. That would be an awesome view, and yes, the houses will disappear there.
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I just placed Google Earth view out to 60,000 feet and I still saw houses, roads, landmarks, etc. :rolleyes:
 
Rotor&Wing said:
I just placed Google Earth view out to 60,000 feet and I still saw houses, roads, landmarks, etc. :rolleyes:
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You think the optics taking those images are the same as the optics in you eyes?:confused::dunno: The comparison is valid how?:dunno: wow....
 
Henning said:
You think the optics taking those images are the same as the optics in you eyes?:confused::dunno: The comparison is valid how?:dunno: wow....
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Unlike you I've been up to FL510, and yet I still saw houses, roads, landmarks, etc.

Your BS is downright comical at times.

BTW, think you could see an exploding barge from 50-60K? :rofl:
 
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Henning said:
I doubt it, regardless that's not the direction I'd be looking if I could get to 60,000'. That would be an awesome view, and yes, the houses will disappear there.
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The human eye has a resolution of between 5.5 to ~11 meters from that distance (18.3 km). As most houses are within that size range, they are certainly visible as are any ships, on fire or not.
 
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Hey Dave,

Just wanted to say thanks for a very educational and entertaining thread here.

After having spent about 2 hours introducing a friend to GA this afternoon (in a 160hp warrior), I got home and started to read this thread... It's fun, I was able to answer every question the friend had today, this thread on the other hand, well, I was aware that I knew very little overall and it's always a learning process, but here comes the fire hose again!

Now I need to figure out how to get some turbine time and learn what n1, 12%, 40%, Hot start, stablize?!? And the many many more things mentioned in this thread are, mean and how they effect the operation of the engine/aircraft.

I'm not looking for definitions, but have found this thread very informative and have enjoyed reading it. Congratulations on the purchase and please keep your questions coming for the me's of the board who have started drinking from a fire hose again!
 
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I meant to add a few explanations to a prior post, but forgot.

The PT-6A turboprop engines on Dave's plane consist of a compessor section (suck, squeeze bang, blow) and a power section that uses the blow (hot gas) to turn a turbine wheel that is connected to one end of a gearbox with a prop on the other end.

N1 (or Ng for generator, the terms are interchangeable) is the speed at which the compressor turns. The typical operational speed is ~35,000 RPM, so percentage numbers are used for convenience and simplification. 12% N1 is equivalent to ~4,200 RPM. During the start process, the compressor must spin up and maintain to a certain speed (~12% N1) prior to adding fuel to the engine. The 40% N1 self-sustain start speed (starter no longer required to maintain rotation and complete the start process) is ~14,000 RPM.

If too much fuel enters the burner can within the compressor section, the resulting fire is called a "hot start" and can damage the metal.

Mattl said:
Hey Dav

Just wanted to say thanks for a very educational and entertaining thread here.

After having spent about 2 hours introducing a friend to GA this afternoon (in a 160hp warrior), I got home and started to read this thread... It's fun, I was able to answer every question the friend had today, this thread on the other hand, well, I was aware that I knew very little overall and it's always a learning process, but here comes the fire hose again!

Now I need to figure out how to get some turbine time and learn what n1, 12%, 40%, Hot start, stablize?!? And the many many more things mentioned in this thread are, mean and how they effect the operation of the engine/aircraft.

I'm not looking for definitions, but have found this thread very informative and have enjoyed reading it. Congratulations on the purchase and please keep your questions coming for the me's of the board who have started drinking from a fire hose again!
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Thank you!!
The "that's impressive" part of my brain likes the numbers (35,000 rpms) over the percentages. Thanks for the explanation as to why the % is utilized, makes complete sense now.

Now to figure out how to get some turbine time :) Or just some time in a turbo piston, hell, I'm happy with time in something with wings!
 
Four instrument approaches; couple on one engine yesterday. Two the day before with no emergencies just to get used to the sim the day before. I'm scheduled to fly this afternoon again (in the sim). This has all been in the Baron sim. They are trying to work in one or two sessions in the KA for me too which doesn't fly a lot different, but it's good to work on and understand systems and what to do with failures that are different than in the Baron. In between, we are either giving or receiving classes on different things. One fella with FedEx did crew resource management and discussed some accidents that resulted from poor CRM. One went over the Baron electrical system in detail (instructors here were asking him questions--he's and EE). One designed a pilot briefing and procedures handbook that was interesting. I was going to cover circle to land approaches, but don't know if I'll have time. Lots of ground school and reading in between. Pretty worn out at night.

Tonight a fella that was on a Special Forces A team with me in RVN is going to drive over and go to dinner. He's just getting to where he can discuss some things that happened way back then.

Best,

Dave
 
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Mattl said:
Now to figure out how to get some turbine time :) Or just some time in a turbo piston, hell, I'm happy with time in something with wings!
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Flying a turbocharged plane is a nice step above a naturally aspirated one. For me, that's my preference. Turbines are a lot of fun... so long as someone else is paying. :)
 
Cap'n Jack said:
The human eye has a resolution of between 5.5 to ~11 meters from that distance (18.3 km). As most houses are within that size range, they are certainly visible as are any ships, on fire or not.
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That's also about Standard Atmospheric Visibility IIRC at 11 miles (standard for measurement of all maritime navigational lights when given)

However, regardless of that, they disappear into the periphery of down. My understanding is that 60k' gives you a near black sky with a full star field in the day light and pearl blue horizon with a curved black terminator. My understanding is that you start to get across that terminator between 50 & 60,000', the higher the better. I want to see that climbing into a western sunrise and take a couple of pictures.
 
Henning said:
That's also about Standard Atmospheric Visibility IIRC at 11 miles (standard for measurement of all maritime navigational lights when given)

However, regardless of that, they disappear into the periphery of down. My understanding is that 60k' gives you a near black sky with a full star field in the day light and pearl blue horizon with a curved black terminator. My understanding is that you start to get across that terminator between 50 & 60,000', the higher the better. I want to see that climbing into a western sunrise and take a couple of pictures.
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Doesn't matter on a clear day. All of the haze is below you by 40,000 feet, so there isn't going to be anything more to absorb or scatter light by 60,000 feet and reduce contrast. Since you still have the contrast, you'll see it if the object is bigger than that 6 to 11 meters I mentioned.

Optical theory notwithstanding, we do have an eye-witness account:
Rotor&Wing said:
Unlike you I've been up to FL510, and yet I still saw houses, roads, landmarks, etc.
<SNIP>
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Lol, still not getting the difference, never mind, I give; 'yeah, if the sky below is clear you can see a house from 60k'.' I just wouldn't be wasting my time looking down.
 
A Baron sim session today and one in the KA.
I was doing too well in the Baron; so, I lost the attitude indicator and had to do several instrument approaches partial panel.

KA time was just normal procedures for awhile, couple ILS approaches, then some failures that weren't too bad: generator, boost pump; a lot of discussion of the start procedure; dead battery on start, etc. I don't think I'd ever consider buying one of these, they have too many failures (g).

Dave
 
Dave Siciliano said:
. I don't think I'd ever consider buying one of these, they have too many failures (g).

Dave
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I think the stress of the upcoming repair bill would cause me to lose my ability to fly the plane.....

Sounds like a good time in the sim!
 
Henning said:
Lol, still not getting the difference, never mind, I give; 'yeah, if the sky below is clear you can see a house from 60k'.' I just wouldn't be wasting my time looking down.
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I think I see your problem now, and understand the comment about the navigation light. A house is big enough so that the unaided eye can identify it as a house (that's why I keep talking about resolution). A nav light has to be bright enough to see over a certain distance. Put two of those lights nine feet apart, and you'll see them as a single light from 60,000 feet, but you'll see the same two nav lights from 60,000 feet if they are 35 feet apart.

I't's interesting looking both up and down from altitude. Flying gives a different perspective both ways.
 
180 kts, is it 5mpg, 7mpg...? If that answer isn't available the question is not so silly.
 
Why would anybody need that information? Airspeed or groundspeed?Does anybody use MPG for trip planning? Each trip is different, winds play a large part.

Henning said:
180 kts, is it 5mpg, 7mpg...? If that answer isn't available the question is not so silly.
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Since a C90 is, by definition, less than 1/3 of a C310 (after all, 90 < 310), Henning is trying to figure out if he could trade his C310 for a C90 and get a significant increase in fuel economy. ;)

I don't use MPG in trip planning, but it is something that I look at to compare efficiency of aircraft. What I typically do, though, is figure out the aircraft's total cost per hour and come up with a $/mile number. The 310 costs about 5-10 cents per mile more than the Aztec. This is acceptable to me, since it's also about 20 kts faster, meaning less time of my butt in that seat to get where I'm trying to go.

Of course, this number is relatively useless since my $/mile can go up by 50% or more with winds. But it makes me feel all warm and fuzzy. Or maybe that's the Scotch.
 
wabower said:
Why would anybody need that information? Airspeed or groundspeed?Does anybody use MPG for trip planning? Each trip is different, winds play a large part.
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Yes, miles per gallon is a vital part of determining total cost of trip to determine operational viability. It's how I show a cost benefit of hauling an owner/pax/parts directly to the boat wherever it lies especially in the out islands with an amphib; clear in most direct POE on runway, then land at the boat with the people/parts. I get 10mpg rather than the 3 gallons to mile and 5 times more time than sending the boat to the POE. Expecially great for parts. I could do basic but feasible service with a LA 24-200 that I'll be in $85,000 by the time I have it on my guy's 135 certificate he said I can use for amicable terms. I'm still trying to sell / trade for a reasonable Buccaneer deal.
 
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Where do you come up with this stuff?

Henning said:
Yes, miles per gallon is a vital part of determining total cost of trip to determine operational viability. It's how I show a cost benefit of hauling an owner/pax/parts directly to the boat wherever it lies especially in the out islands with an amphib; clear in most direct POE on runway, then land at the boat with the people/parts. I get 10mpg rather than the 3 gallons to mile and 5 times more time than sending the boat to the POE. Expecially great for parts. I could do basic but feasible service with a LA 24-200 that I'll be in $85,000 by the time I have it on my guy's 135 certificate he said I can use for amicable terms. I'm still trying to sell / trade for a reasonable Buccaneer deal.
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Ted DuPuis said:
I don't use MPG in trip planning, but it is something that I look at to compare efficiency of aircraft.
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I think you are the only person who has ever asked me the MPG of an airplane. :rofl:
 
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