Normally aspirated motors at high altitudes

[whistleblower]

I'm planning a trip from the southeast US to the Jackson Hole, WY area this summer. I fly a 210 with a normally aspirated IO 550. I'm looking for feedback on normally aspirated performance in the 14-16k range, maybe even as high as 18k (fingers crossed for a nice tailwind heading back east).

Does anyone regularly fly these altitudes with NA engines?

Besides the given decrease in performance, anything else I should be aware of? I don't think this is the case but I'm going to ask anyways: any harmful side effect to the engine from prolonged flight in low oxygen environments?

I'll have portable oxygen with me.

Looking for first hand knowledge/tips/tricks.

 

[kgruber]

Climb will be slow, be patient. Above about 8,000 I lean about 25º ROP for best power.

You won't need anything over 12,500 around Jackson Hole, or anywhere crossing the Rockies VFR on the lower airways. My favorite was always Denver, near Laramie, Rock Springs, Burley.

Don't do it when it is windy. Get up way early, takeoff an hour before sunrise. Quit before noon. You will be fine.

 

[Clark1961]

Best thing to do is to get formal training on high altitude operations.

The engine can handle it just fine. The driver is usually the problem. All the engine needs is to be set up and leaned properly. The driver is going to see a whole new world at high elevation, hot airports. I know you didn't ask about airports, maybe you should.

 

[bluerooster]

What Skywag said.
Just get were yer going and be tied down before noon. (wind can do nasty things in them hills)
I've flown Dads 182 in the hills of CO. with no issues. This is a carburetted, NA O470.
What I found pretty neat is at 1000agl, ALT was reading 9000'. Other than that and a DA of about 10k' at 8am local It's all business as usual, and don't forget to lean the mixture, full rich and you won't make takeoff power.
Have fun.

 

[midlifeflyer]

Where in the southeast, whistleblower? I moved to the Raleigh area last year after 20 years flying and teaching in Colorado.

 

[CharlieTango]

Lean for best power before departing any high altitude field. Lean for best power on approach to be set up for a go around.

 

[N801BH]

I'm planning a trip from the southeast US to the Jackson Hole, WY area this summer. I fly a 210 with a normally aspirated IO 550. I'm looking for feedback on normally aspirated performance in the 14-16k range, maybe even as high as 18k (fingers crossed for a nice tailwind heading back east).

Does anyone regularly fly these altitudes with NA engines?

Besides the given decrease in performance, anything else I should be aware of? I don't think this is the case but I'm going to ask anyways: any harmful side effect to the engine from prolonged flight in low oxygen environments?

I'll have portable oxygen with me.

Looking for first hand knowledge/tips/tricks.

First post...

Welcome to POA......

I "heard" Jackson Hole is a really nice place......

As for NA operation.. Your 210 will be just fine out here. Just plan on less HP and as others have said, Fly in the mornings when it is cool...

 

[Kristin]

It is as much the airframe as the engine. I haven't run a C-210 around the mountains but wouldn't expect any issues related to altitude if you observe the limitations. I run Comanches up to 15-17K all the time. The only real issue is you may have to ride mountain wave conditions as you might not be able to hold altitude.

Check the 12,000 foot winds. You don't want to be out in much more than 25kts at that altitude. Maybe less if you have passengers who will not appreciate a bumpy ride.

 

[Ted]

Went out that direction in November in the 310 with naturally aspirated 520s. It did just fine. I find that 15k and below is really where the plane is happiest. It'll do 17k and be surprisingly happy there, but above 17k, it was unhappy. As Kristin said, it's as much the airframe as anything. I'm not sure how a 210 would do there having no experience with them.

 

[Walt]

whistleblower,
Your 210 will do ok up high but headwinds on the way out will likely have you flying in 10-14K range. Biggest tip I can give you is to be knowledgable about high density altitude takeoffs and landings. NA airplanes are leaned for takeoff and it is an art form that you need to have some experience doing. Too rich a mixture will produce less power and too lean a mixture will produce a lot less power. Use long runways until you get this figured out. Approach speeds are higher because TAS is higher. Again long runways are helpful.

 

[flyingriki]

What I'd give for that kind of cubic inches! My trustie old 320 got me up to 17,500 a few times and we cruised along sweetly. Obviously wasn't in a certified spam can and the GPS said 175 kts.....

 

[murphey]

Best thing to do is to get formal training on high altitude operations.

The engine can handle it just fine. The driver is usually the problem. All the engine needs is to be set up and leaned properly. The driver is going to see a whole new world at high elevation, hot airports. I know you didn't ask about airports, maybe you should.

Stop off in Denver for a day or two and take a lesson from a CFI who specializes in high altitude flying. Number of us here can provide recommendations.

 

[poadeleted20]

Go fly your plane up to those altitudes, and see what vertical speeds you're making and the ground speeds you're getting at Vy. Then take a real good look at the climb gradients (that's gradient, not just rate) you can achieve at those altitudes, and compare them to the gradients required on the ODP's out of KJAC. Then decide if that's something you want to do.

At a Vy of maybe 90 KIAS, your ground speed is near 110 knots, and with a climb rate of maybe 250 ft/min, your climb gradient is not much more than 100 ft/nm -- just barely enough to make the minimum enroute climb gradient above 10,000 MSL of 100 ft/nm, and nowhere near enough to make the 335-450 ft/nm gradients required for the instrument departures. If you're operating VFR, you can work your way up staying in the valley between the ridges until you're high enough to clear the obstructions before heading out on course, but up there above 14,000 or so, all it takes is one little downdraft and you can't stop the descent.

Of course, this is all dependent on weight. Fly that 210 solo, and you get a lot more margin for error. But if you're planning to load up with two couples, holiday baggage, and enough fuel to get straight home, and those margins are completely gone and then some.

My suggestion, then, is to go out in lower terrain, load up the same way you'd be departing KJAC, climb up to 14-18K, and see what you have left. If it isn't enough to handle whatever downdrafts you think you might encounter, do like Nancy Reagan said and "just say no" to that trip plan.

 

[poadeleted20]

What I'd give for that kind of cubic inches! My trustie old 320 got me up to 17,500 a few times and we cruised along sweetly.

Big difference between a twin turbocharged Cessna 320 Skyknight and a single-engine non-turbocharged Cessna 210 when you're talking about air that thin.

 

[poadeleted20]

Went out that direction in November in the 310 with naturally aspirated 520s. It did just fine. I find that 15k and below is really where the plane is happiest. It'll do 17k and be surprisingly happy there, but above 17k, it was unhappy. As Kristin said, it's as much the airframe as anything. I'm not sure how a 210 would do there having no experience with them.

Twin-engine airplanes are, by necessity driven by certification requirements, overpowered when running on both engines. For that reason, Ted's experience with a 310 is not indicative of what a single-engine plane will do at those altitudes.

 

[pericynthion]

Big difference between a twin turbocharged Cessna 320 Skyknight and a single-engine non-turbocharged Cessna 210 when you're talking about air that thin.

He's not talking about a Cessna 320, he's talking about the O-320 in his Long EZ

 

[murphey]

Rule of thumb for weight is at least 10% below max gross for high altitude flights. I regularly fly 10-13K in a cherokee 180.

 

[hiflier]

There sure is a lot of hand wringing when it comes to flying in the mountains. I live in the Sierra where the local airport is at 6,000 and have flown over to JAC in my v35b with an IO 550. I'm always at around 3,000 gross and 90% of the time climb right up to 12,500 or 13,500 and go any place I want without thinking twice. Just go around the high mountains. You're not going to be IFR in the summer because if it's IMC you are dealing with cumulus clouds that you don't want to fly through. In the winter it's ice. The only thing that is always on my mind is turbulence. In the winter you can get some really powerful up-and-down drafts when there is a cold front around and high winds on the lee side. In the summer it's convection. Be ready to slow down to near Va. Like Captain Ron said, take your plane up to JAC field elevation, or whatever, and play with the mixture, etc. and you'll be good to go. The plane will fly fast and economically up at 12-14 and you can keep your IAS down in the 135-145 range in case of turbulence.

 

[BillTIZ]

whistleblower,
Your 210 will do ok up high but headwinds on the way out will likely have you flying in 10-14K range. Biggest tip I can give you is to be knowledgable about high density altitude takeoffs and landings. NA airplanes are leaned for takeoff and it is an art form that you need to have some experience doing. Too rich a mixture will produce less power and too lean a mixture will produce a lot less power. Use long runways until you get this figured out. Approach speeds are higher because TAS is higher. Again long runways are helpful.

Approach speeds are not higher. Fly the same IAS on approach that you would at lower "normal" airports!

The resulting TAS will be higher with higher resulting GS giving the illusion you are flying too fast and the pilots get to slow based on the visual illusion. Pay attention! Results in longer ground roll too.

 

[whistleblower]

I appreciate the replies. Though I've never flown in the rockies, I've been around the Appalachians enough to appreciate winds and waves.

I've taken the plane up to 17k a handful of times to get over buildups but haven't stayed up there long. I'm thinking about trying to go as high as possible on the return leg. With the right tail wind, I may be able to make it non-stop. It'll be close but its not out of the question (160 kts true @ 12 gph w/ 85 usable).

I'm actually heading into Driggs, west side of the tetons.

Mark - I lived in Chapel Hill until about 9 months ago. Great area, I miss it. Out of Atlanta now.

 

[midlifeflyer]

Driggs is a good choice. Once over Teton Pass

the approach to the airport is wide and accessible

But if you don't stop for some mountain instruction with a local while still in the plains please take the time to discuss the choice of route and mountain. My wife took those photos from the normally-aspirated Debonair we flew on this Colorado Pilots Association fly-out trip. Members flew in in a variety of aircraft, many far less capable than yours. But we lost one member on flying a JetProp Bonanza on the way home (the NTSB has still not issued a probable cause determination after almost 3 years and I hate to speculate on the causes)

 

[Ted]

Twin-engine airplanes are, by necessity driven by certification requirements, overpowered when running on both engines. For that reason, Ted's experience with a 310 is not indicative of what a single-engine plane will do at those altitudes.

You forgot about the fact that my 310 experience is on a 310 with 300 HP engines upgraded from the factory 260 HP.

But you are correct, I was not claiming my 310 experience was going to be the same as 210 experience. My point was that the engines (which are ostensibly the same - 520s vs. 550s) seemed happiest in those altitude ranges as well.

 

[Jthamilton]

Beautiful pics, camping at Yellowstone in airplane on short list for this year.

Look up the next mountain flying course sponsored by Colorado Pilots association. Great class, if you can squeeze it in I highly recommend it!! Course definitely weighed for those with NA aircraft. I kind got feeling that I was cheating with owning a Turbo. It definitely made me better pilot.

 

[murphey]

Beautiful pics, camping at Yellowstone in airplane on short list for this year.

Look up the next mountain flying course sponsored by Colorado Pilots association. Great class, if you can squeeze it in I highly recommend it!! Course definitely weighed for those with NA aircraft. I kind got feeling that I was cheating with owning a Turbo. It definitely made me better pilot.

June 7 (Sat - all day ground) Flying next day or when able to schedule. Out of towners get priority.
Sept 6 - same as above.

www.coloradopilots.org

 

[poadeleted20]

You forgot about the fact that my 310 experience is on a 310 with 300 HP engines upgraded from the factory 260 HP.

You're right -- and that only makes the difference larger.

But you are correct, I was not claiming my 310 experience was going to be the same as 210 experience. My point was that the engines (which are ostensibly the same - 520s vs. 550s) seemed happiest in those altitude ranges as well.

The engines may be happy, but the issue is excess power, and for a 210 at those altitudes, there's a whole lot less of that than even a stock 310.

 

[flyingcheesehead]

I'm planning a trip from the southeast US to the Jackson Hole, WY area this summer. I fly a 210 with a normally aspirated IO 550. I'm looking for feedback on normally aspirated performance in the 14-16k range, maybe even as high as 18k (fingers crossed for a nice tailwind heading back east).

Does anyone regularly fly these altitudes with NA engines?

Besides the given decrease in performance, anything else I should be aware of? I don't think this is the case but I'm going to ask anyways: any harmful side effect to the engine from prolonged flight in low oxygen environments?

Nothing to worry about in terms of the engine itself - Just be aware that at 18K you won't be able to get more than 50% power.

FWIW, I've had a normally aspirated fixed-gear 182 (O-470) up to 17,500 in the summer, and I've had a normally aspirated Mooney Ovation (IO-550) up to 19,000 once and 16,000 quite a number of times.

It does depend on the airframe, but a Cessna wing won't have any issues up there.

What you do need to worry about is flying in between the rocks as well as takeoffs and landings. I'm going to break with the rest of the folks and say that the Colorado Pilots' mountain course is not the one you want - Not because they're doing anything wrong, but because there aren't really any backcountry/difficult strips to land at there. If you're going to Idaho, keep on going to McCall and Mountain Canyon Flying. They'll not only teach you how to fly around the mountains, they'll also teach you how to get in and out of some amazing backcountry strips. Awesome.

Have a safe and enjoyable trip!

 

[jaybee]

I landed at Leadville as a Private Pilot with only 70 hours total time of flatland experience in a T41B which is just a 172 with a controllable prop.

Not saying to not be mindful of what has been said but its not that big of a deal IMHO.

 

[poadeleted20]

I landed at Leadville as a Private Pilot with only 70 hours total time of flatland experience in a T41B which is just a 172 with a controllable prop.

...and a 210HP engine compared to the 145HP with which that airframe was originally designed. With that engine and prop, the T-41B develops at least as much power on takeoff at Leadville as an original T-41A (essentially a pre-68 Cessna 172) develops on takeoff at sea level -- and that's a huge factor. That engine was specifically installed in the B-model T-41 at USAF request to make it more suitable for operations at Colorado Springs CO, where the DA in the summer runs up to 10,000 or more.

Not saying to not be mindful of what has been said but its not that big of a deal IMHO.

What makes it not that big of a deal is an engine 50% bigger than originally used on the airframe, and at 10,000 MSL, the OP"s stock C-210 doesn't have that large excess power margin you had in that T-41B.

 

[Henning]

Go fly your plane up to those altitudes, and see what vertical speeds you're making and the ground speeds you're getting at Vy. Then take a real good look at the climb gradients (that's gradient, not just rate) you can achieve at those altitudes, and compare them to the gradients required on the ODP's out of KJAC. Then decide if that's something you want to do.

At a Vy of maybe 90 KIAS, your ground speed is near 110 knots, and with a climb rate of maybe 250 ft/min, your climb gradient is not much more than 100 ft/nm -- just barely enough to make the minimum enroute climb gradient above 10,000 MSL of 100 ft/nm, and nowhere near enough to make the 335-450 ft/nm gradients required for the instrument departures. If you're operating VFR, you can work your way up staying in the valley between the ridges until you're high enough to clear the obstructions before heading out on course, but up there above 14,000 or so, all it takes is one little downdraft and you can't stop the descent.

Of course, this is all dependent on weight. Fly that 210 solo, and you get a lot more margin for error. But if you're planning to load up with two couples, holiday baggage, and enough fuel to get straight home, and those margins are completely gone and then some.

My suggestion, then, is to go out in lower terrain, load up the same way you'd be departing KJAC, climb up to 14-18K, and see what you have left. If it isn't enough to handle whatever downdrafts you think you might encounter, do like Nancy Reagan said and "just say no" to that trip plan.

Holy crap, Jackson Hole has tons of room to climb to get out of, and the 210 isn't that bad a performer. Just do it on a decent VFR morning which you get most of the summer and it's all good. With an IO 550 rated for 300hp you'll still have 245hp or so taking off out of Jackson Hole, and they have a long runway and a big bowl to climb if you need.

 

[Tom-D]

I'm planning a trip from the southeast US to the Jackson Hole, WY area this summer. I fly a 210 with a normally aspirated IO 550. I'm looking for feedback on normally aspirated performance in the 14-16k range, maybe even as high as 18k (fingers crossed for a nice tailwind heading back east).

Does anyone regularly fly these altitudes with NA engines?

Besides the given decrease in performance, anything else I should be aware of? I don't think this is the case but I'm going to ask anyways: any harmful side effect to the engine from prolonged flight in low oxygen environments?

I'll have portable oxygen with me.

Looking for first hand knowledge/tips/tricks.

Follow Skywag advice and you be OK, there is no reason to go to 18k',

what it looks like from a 165 horse power Fairchild 24 we were only 12,500" when these pictures were taken.

 

[Tom-D]

Holy crap, Jackson Hole has tons of room to climb to get out of, and the 210 isn't that bad a performer.

every one knows that you can't go west of the Mississippi with out high altitude training and a turbo charged 1000 horse powered aircraft.

 

[N801BH]

Holy crap, Jackson Hole has tons of room to climb to get out of, and the 210 isn't that bad a performer. Just do it on a decent VFR morning which you get most of the summer and it's all good with an IO 550 rated for 300hp you'll still have 245hp or so taking off out of Jackson Hole, and they have a long runway and a big bowl to climb if you need.

Agreed..... Ron has painted a very ugly and false picture of a 210 with reduced power.... People fly out here daily with non turboed motors and live to see another day... The OP was a newbie here asking a simple but honest question and some people here are trying to scare him into not flying above 1000msl......

 

[jaybee]

Agreed..... Ron has painted a very ugly and false picture of a 210 with reduced power.... People fly out here daily with non turboed motors and live to see another day... The OP was a newbie here asking a simple but honest question and some people here are trying to scare him into not flying above 1000msl......

Exactly why I posted my experience above. Flew 180 S model 172 at sea level getting my rating. Was up at the Academy doing some work as a wet ink Private Pilot I took a T41B ( and an Instrctor from Petersen AFB ) which is like a whole 20 hp more and flew into Leadville. Again, IHMO not a big deal.

 

[midlifeflyer]

Exactly why I posted my experience above. Flew 180 S model 172 at sea level getting my rating. Was up at the Academy doing some work as a wet ink Private Pilot I took a T41B ( and an Instructor from Petersen AFB ) which is like a whole 20 hp more and flew into Leadville. Again, IHMO not a big deal.

Let's make that a whole 30 hp more - almost 20% hp more in an aircraft already capable of performing pretty well in the hands of a knowledgeable pilot (I have been into Leadville more than once in a 180 HP 172).

Just be aware that your humble "no big deal" opinion has been held by many others with even more power at their disposal. You can read about them in the NTSB database. Just search for "GA" and "fatal."

That's not to scare anyone. Ron, as usual, is going a bit overboard. But there are indeed considerations when flying in high mountainous terrain and high density altitude that require, at the very least, study from a knowledgeable source. Not everyone absolutely needs a mountain flying course to "get it" but I'd say that most flatlanders I've done basic mountain training with (we're talking regular public airports, not backcountry strips) have been surprised by at least some parts of the very normal flight.

 

[Clark1961]

Let's make that a whole 30 hp more - almost 20% hp more in an aircraft already capable of performing pretty well in the hands of a knowledgeable pilot (I have been into Leadville more than once in a 180 HP 172).

Just be aware that your humble "no big deal" opinion has been held by many others with even more power at their disposal. You can read about them in the NTSB database. Just search for "GA" and "fatal."

That's not to scare anyone. Ron, as usual, is going a bit overboard. But there are indeed considerations when flying in high mountainous terrain and high density altitude that require, at the very least, study from a knowledgeable source. Not everyone absolutely needs a mountain flying course to "get it" but I'd say that most flatlanders I've done basic mountain training with (we're talking regular public airports, not backcountry strips) have been surprised by at least some parts of the very normal flight.

Spot-on as usual Mark. I find it mildly humorous that Stratobee did exactly what some folks are recommending, he flew with a CFI so he did get some training. Yes, of course Ron and Ben are exaggerating - such is life.

 

[Neal Howard]

My 160hp normally aspirated RV-6 loaded full of camping gear did just fine in the mountains. But being an RV makes the comparison to a factory spamcan a bit unfair, at 13-14K MSL it would still outclimb what a Cherokee 140 will do at flatland altitudes :wink2:

A trick I was taught to see what your takeoff performance will be like at high altitude airports is to climb up to high altitude and and see what kind of manifold pressure your engine will make at a normal climb attitude up there at full power/prop full forward, etc. Then try taking off from a nice long runway, limiting yourself to just that amount of manifold pressure, or perhaps an inch less and then see how long your takeoff roll becomes. Of course, make sure you have a runway with ample excess length plenty long enough for this experiment first

 

[flyingcheesehead]

A trick I was taught to see what your takeoff performance will be like at high altitude airports is to climb up to high altitude and and see what kind of manifold pressure your engine will make at a normal climb attitude up there at full power/prop full forward, etc. Then try taking off from a nice long runway, limiting yourself to just that amount of manifold pressure, or perhaps an inch less and then see how long your takeoff roll becomes. Of course, make sure you have a runway with ample excess length plenty long enough for this experiment first

The problem is, that experiment isn't an accurate simulation: If you take off with, say, 22" of MP from a sea level airport, you'll still get up faster than you would with 22" MP from an airport at 8000' because your prop and wing are biting into thicker air.

 

[Neal Howard]

The problem is, that experiment isn't an accurate simulation: If you take off with, say, 22" of MP from a sea level airport, you'll still get up faster than you would with 22" MP from an airport at 8000' because your prop and wing are biting into thicker air.

This is true, but it's not meant to be a laboratory accurate simulation, it's just intended give you a taste of what it feels like to have substantially reduced takeoff power available.

 

[Jaybird180]

The problem is, that experiment isn't an accurate simulation: If you take off with, say, 22" of MP from a sea level airport, you'll still get up faster than you would with 22" MP from an airport at 8000' because your prop and wing are biting into thicker air.

True, however it's the best simulation you can get esp with -1"MP

 

[Clark1961]

True, however it's the best simulation you can get esp with -1"MP

At least it should teach you that ya can't just pitch up 8 to 10 degrees and hope to climb out...and that ya might taxi for awhile prior to rotation