How high can you go without a turbo?

[gismo]

It was too windy to fly the Porterfield today, so I took the Baron up instead. And "up" is the key word in that phrase. I've often wondered how high it would go and today I easily got to FL 220. I could have gone higher, but ATC gave me some nonsense about not being able to let me above there due to "military traffic in the area" (this was 10-20 miles outside the MSP Class B lateral extent). Anyway I could still climb 400 FPM at FL 220 and I'm guessing I might have made FL 240 or FL 250 given enough time. Of course I cheated by starting out about as light as I ever fly the plane with only 50 gallons of fuel and just me in the cabin. Still I was amazed that there was still a lot of climb left up that high.

Several years ago I tried the same thing in an older Bonanza and couldn't get more than a few hundred feet above FL 180. That time I wasn't so light, with a 220 lb friend in the right seat and several hours of fuel, plus it was a very hot day.

It sure took a lot less time in the Baron than the Bonanza. Today I made it to FL 180 in less than 20 minutes from the takeoff roll and that included levelling off a couple times for ATC (the Bo took close to twice that long). I had no trouble keeping the engines cool in the Baron either. In fact it seemed that the CHT's actually went down as I climbed past 15,000.

Anybody else attempted taking a plane to it's absolute ceiling?

 

[Tom-D]

I'v had a C-150 to 14k, it gets kinda puney up there.
I'v had my F-24 up to 14k too, it was still climbing.

 

[bbchien]

Cessna 205 with one up and 60 gallons of fuel (1200 undergross) easily made FL 21 eastbound. It does get quiet, however.

 

[Carol]

I've been to 14,500 in the Comanche crossing the Rockies with full fuel and luggage and I was the only soul on board. I wasn't trying to go any higher. Maybe next time I will check it out. The book says the service ceiling is 21,000. Not sure I am willing to attempt that.

 

[James_Dean]

I've had the 'toga to 16,000 @ 700 under gross and was climbing 400 fpm.

I know that each individual has different physiological response but,

At what altitude is supplemental oxygen not adequate?

Can you go higher with a cannula vs a mask?

Bruce, to go to FL210 in a 205 you must have been on a long trip and chasing some big winds!

Is there an ambient temperature where 100LL will start to have flow problems?

RSVM applies to FL270 and above? That would obviously apply to piston driven birds as well. I seem to remember that Deakins writing an article where he took his Bo to FL290. Are there any piston powered planes that are certified above FL270? Lancair?

James Dean

 

[Dave Siciliano]

Lance:
You're probably aware I took 2024Q up to FL 250. Still had 25 inches of MP. My passenger and I were both on oxygen and didn't really care to go higher. I think 29,000 would have been doable; then; we'd have had a problem with ATC and airline FLs. We had full fuel, two of us in the plane and he's over 200 pounds and we had some baggage. Of course, this is a turbonormalized plane.


Best,

Dave

 

[gismo]

I know that each individual has different physiological response but, At what altitude is supplemental oxygen not adequate?

Above 44k you need a pressure suit or pressurized cabin, so I guess you can say that supplemental O2 isn't adequate above that. From 35k-44k you need a pressure mask.

Can you go higher with a cannula vs a mask?

AFaIK all cannulas are limited to 18k, and a mask is needed above that.

Is there an ambient temperature where 100LL will start to have flow problems?

Gasoline freezes around -57C. The standard atmosphere bottoms out around -56.5C at 35000 MSL and the temp goes back up above 60000 MSL. While that sounds a bit too close for comfort, as long as you were flying in the daytime, solar heating should keep you safe assuming no water in the fuel tanks.

RSVM applies to FL270 and above? That would obviously apply to piston driven birds as well. I seem to remember that Deakins writing an article where he took his Bo to FL290. Are there any piston powered planes that are certified above FL270? Lancair?

Some Aerostar models have a service ceiling of 30,000.

 

[bbchien]

AFaIK all cannulas are limited to 18k, and a mask is needed above that.

And the non pressure fit mask tops out at 24K. The Scott 2000 pressure fit system will do to about 29K.

Some Aerostar models have a service ceiling of 30,000.

This latter has more to do with decompression certification; the routine for demonstrating rapid descent to 10,000 within one minute, etc.

 

[John J]

Anybody else attempted taking a plane to it's absolute ceiling?[/QUOTE]

I took a Aeronca 65-7AC to 9,800+ on a very warm summer day. I tried for 10 but it just could not go any more. It took close to an hour. I even looked for thermals but ran out of them as well. It is amazing when you reach the aboslute ceiling for it is flying right on the edge of the stall. Definately it is flying behind the power curve. The trip down was fun and we did not shock cool that little engine.

John J

 

[Let'sgoflying!]

Anybody else attempted taking a plane to it's absolute ceiling?

I am still wondering why that empty RJ went in recently somewhere in the midwest(?), when the pilots took it to 410, the reported service ceiling for that a/c. Seems like they had two engine failures (compressor stalls?). Could they have been yanking and banking to such an extreme that the engines couldn't get air, but the wings & tail continued to fly ok? That one has me puzzled.
Also once they got it lower, a relight at least of one engine would have been routine I'd'a thought.

 

[ejensen]

I've been to 14,500 in the Comanche crossing the Rockies with full fuel and luggage and I was the only soul on board. I wasn't trying to go any higher. Maybe next time I will check it out. The book says the service ceiling is 21,000. Not sure I am willing to attempt that.

I rode in a 260 with three plus baggage home from ABQ. Made 165 with no sweat. I was impressed.

Eric

 

[ejensen]

Is there an ambient temperature where 100LL will start to have flow problems?

I had an 0-470 start running real rough at -50F @12,500. Carb heat smoothed it out. Later folks suggested the fuel was not atomizing properly.

Eric

 

[Dave Siciliano]

I believe Mountain High is currently touting a cannula system that is good into the low 20s. I'll have to check. Standard cannulas are limited to FL180 as Doc said.

Don't know why a mask would be limited to FL240. I measured my blood saturation level at FL250 and it was 94% at that level. It's only 96 at ground level. I've tested and found that below 85 ot 86 starts to have a negative effect on me.

Best,

Dave
A-36TN ADS

 

[bbchien]

Eric, either that or the air was so dense that by using carb heat, you have a longer draft tube which decreases the number of oxygen molecules (warmer is less dense) and the mix came back into the "stochiometric" mix range again.

Boost pump might have had the same effect- but who cares if it's running right again?!

 

[ejensen]

I tried changing the mixture too with little effect. I had Kremmling made so wasn't too worried. Still nice to hear it come back to full power.

It was -30 when we left Fort Collins in a 182. Can you say drafty!

Eric

 

[gismo]

I took a Aeronca 65-7AC to 9,800+ on a very warm summer day. I tried for 10 but it just could not go any more. It took close to an hour. I even looked for thermals but ran out of them as well. It is amazing when you reach the aboslute ceiling for it is flying right on the edge of the stall. Definately it is flying behind the power curve. The trip down was fun and we did not shock cool that little engine.

John J

Actually, you will coax out the maximum altitude at a speed quite a bit higher than Vs1. The exact best speed is Vy compensated for altitude. Halfway between the published Vx and Vy is about right. Still, nearly 10k ft in an 65 hp Aeronca, is pretty impressive. I assume that like my Porterfield, there is no mixture control so you'd be running very rich up there.

 

[grattonja]

I had a 172M up to 15,500 during mountain flight training over CO last year. Lots of updrafts to boost us up there though. It was pretty cool to be so high up. O2 cannula of course.

Jim G

 

[waldo]

My brother and I was on a short VFR cross country from Concord, CA to Baton Rouge, LA (little over 1700 mile route) in a Cherokee 140 with the 160hp engine. It was during the first part of May 2004. From Casa Grande to Deming we had to climb to get over the mountains and we could only get 11,300 to 11,500 MSL. I don't remember what the Density Altitude was that day but the little Cherokee had all that she wanted. It was an absolutely wonderful trip!

:dance:

Fly Safe,
Waldo
N7064W

 

[Earthroamer]

My brother and I was on a short VFR cross country from Concord, CA to Baton Rouge, LA (little over 1700 mile route) in a Cherokee 140 with the 160hp engine. It was during the first part of May 2004. From Casa Grande to Deming we had to climb to get over the mountains and we could only get 11,300 to 11,500 MSL. I don't remember what the Density Altitude was that day but the little Cherokee had all that she wanted. It was an absolutely wonderful trip!

:dance:

Fly Safe,
Waldo
N7064W

I took our LJ45 up in the FL500's also just to see it and then came back down. Had all I wanted too.

Brent

 

[John J]

Actually, you will coax out the maximum altitude at a speed quite a bit higher than Vs1. The exact best speed is Vy compensated for altitude. Halfway between the published Vx and Vy is about right. Still, nearly 10k ft in an 65 hp Aeronca, is pretty impressive. I assume that like my Porterfield, there is no mixture control so you'd be running very rich up there.

Lance;

Your are very right. At the time I was a young 16 student pilot. The descenty altitude must have been close to 11 to 12k for it was 85 to 90 degrees at sea level. There was no mixture control and that little Continental was working real hard. If I had the mixture control I most likey would have gotten more out of the plane. The oil temp stayed cool all the way.

I remember seeing Porterfields when I was a young airport kid and I thought they wre great and for years wanted one. But the Aeronca was such a joy to fly and the price was right. 10 hours of work to get 1 hour of flying time.

Thanks for the tip on climb speeds at high altitudes.


John J

 

[poadeleted20]

I am still wondering why that empty RJ went in recently somewhere in the midwest(?), when the pilots took it to 410, the reported service ceiling for that a/c. Seems like they had two engine failures (compressor stalls?). Could they have been yanking and banking to such an extreme that the engines couldn't get air, but the wings & tail continued to fly ok? That one has me puzzled.

Stacey Kotrla, who flies these jets for a living, gave a pretty good summary of the problems they ran into over on the AOPA Web Board, but I don't remember the details and I can't retrieve them now. However, while yanking and banking at low Q can cause compressor stalls (BTDT -- attempted roll in an F-111 at about FL 250 and 300 KIAS -- left engine went "pop" but recovered as soon as it was pulled back to idle), that was not the issue in this case.

Also once they got it lower, a relight at least of one engine would have been routine I'd'a thought.

It would, except that for reasons Stacey covered, you have to get down below FL 260 before even attempting a relight in this jet. They didn't do that, and then I believe they gave up trying when neither engine relit up high.

 

[Let'sgoflying!]

I took our LJ45 up in the FL500's also just to see it and then came back down. Brent

Brent, I had a DE tell me that if you have an explosive decompression above about 310 then its all over, you will never get a mask on (if not wearing one already). Do you believe it? Even with TUC from charts, the noise, fog and burst eardrums, gas evolution in the body would make it pretty much impossible to function.

 

[Earthroamer]

Brent, I had a DE tell me that if you have an explosive decompression above about 310 then its all over, you will never get a mask on (if not wearing one already). Do you believe it? Even with TUC from charts, the noise, fog and burst eardrums, gas evolution in the body would make it pretty much impossible to function.

Yes, to an extent, I would believe it. I think you would be fine at maybe FL310. In the FL400's and FL500's, I dont even think you would have time to say, "WWhhhhhhaaaaaattttttt". It would all be over. There are published time tables of just how much time you will have during a decompression. It gets dramatically small when in the upper 30's (were talking down to seconds). We train at FSI for it but most pilots know that you are pretty much screwed if you are up high. For that reason, is why I stated initially what I did. Slow decompressions are most likely what you will really see. For example, door seals splitting apart. I know of one crew that had this recently. It was manageable and they got down, but if they would have been in the FL500's then it would have taken longer to get the plane down. The air is really thin and you cant just pitch it over and come down.

Some pilots also state that the amount of radiation in the 40's and 50's are pretty high. With the coffin cornor and the radiation, I really dont see a need to get up there even though the plane will do it easily. You most likely will not save more fuel going above 410 or 430 compaired to 510. If it's a thunderstorm you are trying to top, you shouldn't be there either. Go around. I usually fly 410 and below. I know that for our a/c's it doesnt take but maybe 390 or so for the plane to feel like it's back in thicker air and you can start coming down easily.

I just wanted to see the 50's and then I was done.

Brent