High altitude, non-turbo flight

[Tx_Aggie]

Having owned my J for 4 years now, I’ve never taken it up beyond 11,000’ yet. I’ve read on here that several of you have some kind of oxygen set up and take advantage of the winds when they’re favorable. 
 

my question this time is, what is your typical power setting, outside of WOT? Full rpm? What mixture settings (ballpark) for say 13-18k?

 

thanks!

[mike_elliott]

Que up the ROP/LOP rants!

[M20F]

6 hours ago, Tx_Aggie said:

. I’ve read on here that several of you have some kind of oxygen set up and take advantage of the winds when they’re favorable. 
 

I have a RayJay and I rarely go high because the winds really need to be blowing and the trip has to be long to beat 6000-9000 feet.  Without a turbo it would be once in a lifetime that climbing up in the teens is ever going to work.  Certainly you can do it and there are people here who have taken NA Mooney’s into the FL’s for fun but not really for practicality. 

 

[Steve Dawson]

Climbed to 14K once to get over some mountains in my J model. I used a portable oxygen system and a pulse oximeter to watch my O2 levels. WOT, 2500 RPM and lean to best power since you'll below 65% power and won't be in danger of hurting the engine. 

[gabez]

get a pulse ox and try different altitudes from 9-11K and see how your blood oxygenation reacts. Usually at 11-12K I am sitting at about 83 and I am still fine but once I cross the 12K I always use oxygen. you can buy a tank at aircraft for 500 bucks and it comes filled already 

[N201MKTurbo]

I used to fly my M20F over the Rockies almost every day back in the 80s. I would cross one way at 12500 and the other way at 13500. It went up there with no problem. I occasionally did it IFR at 16000. 
 

I was young and lived in Denver, so I didn’t use oxygen up to 13500. Once I got pushed up to 17000 in a mountain wave without oxygen. I found that changing channels on the radio was a lot of effort. I was up there for less than a minute before I was able to get back to 12500.

[201Mooniac]

I always use O2 when at or above 10000, used to use a portable bottle, now an O2 concentrator.  As to the mixture question, in my M20J as close as I can recall I would be seeing about 8gph at 13000 but I just head on up and lean as normal, no red box to worry about up there.

[Fritz1]

Can make sense with jet stream on your tail, portable O2, WOT, best power mixture, about 100 dF rich, RPM 2400 -2500, jet stream in winter can be 100kt in the mid teens

[Shadrach]

I frequently cruise 11.5  or 12.5 on long cross countries. I’ve seen ground speeds over 200kts more times than I can count and  on few occasions topped 240. 

Throttle is set wide-open from takeoff until I have some reason to reduce manifold pressure (rough air, non-standard descent profile or slowing down to enter the pattern for landing)

I only fly lean of peak EGT at DAs below 5000 feet where there’s a surplus of air to make good power. Starting at about 5000 feet I run much closer to peak EGT  until I get  to 10,000 or above where I run 100 Rich of Peak EGT.

This works out great for flight planning purposes as the delta in fuel burn from say 2500 feet (LOP) to 11,500 (100ROP) is relatively small. The same can be said for TAS. 

There really is not much reason to run a normally aspirated Lycoming, lean of peak EGT when peak is sufficient to keep CHTs in check.

I set RPM around 2500 because it feels like the sweet spot in terms of smoothness and noise. I’ve also been told that’s where my prop is most efficient.

I have found this to be the simplest way to manage the power plant. It yields good speed, good efficiency and cool CHTs with minimal effort.

[EricJ]

Living in the southwest or western US it's not unusual to be cruising above 10k.    I had my J at nearly 18k coming over the rockies thanks to a mountain wave, and I took the opportunity to just cruise at the higher altitudes for a while to enjoy the view (I had O2).

As previously mentioned, WOT and 2500 rpm is a good choice (it's pretty much what I always cruise at anyway), so really the only issue is leaning it to some suitable EGT.   If you want a little more power, then increasing rpm is an option.

[Shadrach]

my little F model doing its best impression of an Acclaim at 25,000 feet. Except for I’m burning under 10 gallons an hour and I don’t have a hose in my nose. I should’ve gone higher just to see how fast it would go but I was only 22 miles from my destination.

 

[AndreiC]

I have only had my E for a little over a year, but I am very happy that it can go much higher than the Cherokee 180 I had before. It has allowed me to go over mountains I would not have gone over before. I have been at least twice over 15k, once going over the Grand Canyon to avoid the restricted area, and a couple of times going over the Sierras. Usually this is the reason I'll go high (many times around 12k), to avoid mountains or clouds. Did not try it for speed. I use a portable oxygen bottle. As @Shadrach said, full throttle, ram air on, 2550 or 2600 rpm, mixture to peak or somewhat rich of peak. Definitely see a slower TAS, but I don't remember exactly what it was. 

Here she is at 15.5.

[Ragsf15e]

Certainly out west it’s nice to cruise in the mid teens on occasion.  Don’t plan on it max gross weight.  You can probably get there but the climb is slow and the cruise feels mushy.  One or two occupants in a light plane with cool temperatures, it’s definitely an option. Rich of peak and 2500 RPM will be your friends.

[wombat]

3 hours ago, N201MKTurbo said:

I used to fly my M20F over the Rockies almost every day back in the 80s. I would cross one way at 12500 and the other way at 13500. It went up there with no problem. I occasionally did it IFR at 16000. 

I took my M20E up to > 17,000 several times.    Never got it to FL180 though.   Here is a picture of it at 17,000 on my way to Missoula.

[N201MKTurbo]

1 hour ago, wombat said:

I took my M20E up to > 17,000 several times.    Never got it to FL180 though.   Here is a picture of it at 17,000 on my way to Missoula.

You are moving along pretty good for that altitude.

[Shadrach]

1 hour ago, wombat said:

I took my M20E up to > 17,000 several times.    Never got it to FL180 though.   Here is a picture of it at 17,000 on my way to Missoula.

The worn and stained grip tape on the yoke really gives that photo a 1940s feel that is spoiled only by the moving  map on the 430.

@Immelman has had his naturally aspirated E to 21.5 many years ago.  There was a video from the cockpit but it has since been made private. 

[Shadrach]

 

40 minutes ago, N201MKTurbo said:

You are moving along pretty good for that altitude.

Of course he is...Can't you see the "Power Boost" control is in the full aft position.  That's got to be good for at least .012" of manifold pressure at that altitude and indicated airspeed.

[wombat]

4 hours ago, N201MKTurbo said:

You are moving along pretty good for that altitude.

Tailwinds!  Indicated airspeed about 108, and 17k altitude, if I remember right it was right around 0C, and the altimeter setting was 30.20, which gives me a TAS of 145, so to get to a 167Kt ground speed, that gives me 22 knots of effective tailwind.

3 hours ago, Shadrach said:

 

Of course he is...Can't you see the "Power Boost" control is in the full aft position.  That's got to be good for at least .012" of manifold pressure at that altitude and indicated airspeed.

If I remember right, the "Power Boost" switches you from flying in MPH to flying in Knots; a 15% increase in speed.

[sleeper-319]

I have a mountain high O2D2 system and a D bottle. It works pretty well. I leave the engine full throttle and 2400 or 2500 RPM.

I frequently fly over 10k because you gotta get up there time you leave California (and sometimes even to go SoCal to NorCal). But I don’t fly above 12.5 all that often; maybe a handful of times per year.  For longer trips that are more than a couple hours at >= 10k, using O2 is great for reducing fatigue even when I’m not at altitudes that require O2. 

I’ve experimented enough that I know my symptoms of decreasing O2 sat pretty well (I start to yawn a lot when it dips below 90). Even without supplemental O2, I can keep the level above 90 with focused, intentional breathing. The cannula takes a little getting used to, I have to pay attention to my breathing to make sure I’m inhaling through the nose, and not taking shallow breaths. The system works well but I might buy a concentrator if I were doing it again.

[GeeBee]

The original owner of my Ovation set a NAA speed record LAS-PIT flying it at FL230 all the way. She tells me it she was solo and it got right up there and flew easy all the way.

[Ragsf15e]

So here we are today in my lowly F at 14,500’ to stay on top and out of the bumps below.  All 4 of us on oxygen because we cruised there for an hour or so.  We were about 200lbs below mgw as we climbed up and climb was anemic between 12500-14500, but she still cruised ~140kts at 100rop and 2500rpm.  It does much better if there’s less weight.

 

[rturbett]

I believe we were at 11k when bringing the plane home when I snapped this. Pretty excited about the ground speed.

I've had problems hiking at 10k so I was nervous about higher altitudes. Turns out when you are just sitting in an airplane, its much easier! pulse ox remained at 98%

Funny that we passed Mt San Jacinto at 11k where I had experienced the oxygen challenges at 10k

[Ragsf15e]

1 hour ago, rturbett said:

I believe we were at 11k when bringing the plane home when I snapped this. Pretty excited about the ground speed.

I've had problems hiking at 10k so I was nervous about higher altitudes. Turns out when you are just sitting in an airplane, its much easier! pulse ox remained at 98%

Funny that we passed Mt San Jacinto at 11k where I had experienced the oxygen challenges at 10k

Sounds like you were using a pulse ox which is good, but I find it very unlikely that your pulse ox was above low 90s at 11,000 feet without O2 Unless you live at very high elevation. I fly a lot out west and we are all affected differently, but I see mine decreasing starting around 8000. If I cruise at 11,000 for a long time, I’ll probably be sitting high 80s low 90s. standby oxygen or I use an oxygen concentrator is very helpful. Maybe try a couple different fingers?

[rturbett]

I took a deep breath before climbing to altitude... or I was hypoxic and couldn't read it correctly!  If I recall correctly, my instructor was at 94%  

I also did some repetitive mental tasks to "judge myself" along the way...

For my normal flying- which is still being determined - I'm usually below 9k

 

[Ragsf15e]

46 minutes ago, rturbett said:

I took a deep breath before climbing to altitude... or I was hypoxic and couldn't read it correctly!  If I recall correctly, my instructor was at 94%  

I also did some repetitive mental tasks to "judge myself" along the way...

For my normal flying- which is still being determined - I'm usually below 9k

 

I think you’ll find very little loss of simple mental tasks and you probably won’t notice a lack of judgment.  You likely won’t have significant hypoxia like people talk about in the altitude chamber if you’re just cruising at 10-12k even though there’s likely some degradation there.  You’ll really need to use a pulseox repeatedly to see the dip.  What you’re most likely to notice is the change in fatigue after (or even during) a flight. Those yawns you mention?  Sure you’re not tired?  How do you feel in the evening after a long flight, maybe a little tired?  O2 makes a huge difference there.