Mountain flying in a M20E

[mike_elliott]

3 minutes ago, midlifeflyer said:

That's a great method for hitting your target EGT for leaning even at altitude (whether LOP or ROP). But the typical  leaning for high D-Alt takeoff in a normally aspirated airplane involves something richer than best power to allow for better cooling. Basically, neither our engines nor airfoils (including prop) are as powerful/efficient at higher density altitudes so they work harder - think of an extended climb at cruise power  with your wings providing less life and your prop providing less thrust.

It, as all ops anywhere anytime, require your plane to be cooling correctly, have the baffling correct, timing correct, etc. The CHT's and EGTs take this lack of air into account at high DA's. If richer ops are needed, it might mean you need to review your cowl flap settings, baffling, etc. 

Climb VY until out of the kill zone, then at 120 for better cooling, but Bob knows this.

 

 

[Ross Taylor]

So, we just returned from our trip to Truckee-Tahoe yesterday evening.  While on this trip, I wasn't keeping up with the thread and am just now seeing a question about our high altitude leaning.  I lean to max RPM during run-up, then dial in (richer) two turns.... but that's just me, for starters.  I watch my JPI and richen as needed from there, but have found that seems about right for us.  Maybe 2 turns is more than needed, but I'd rather run a bit rich (here) than be too lean during take off.  I do aggressively lean during taxi and in cruise.

As far as this trip goes, we took off from Truckee-Tahoe at about 1pm yesterday and the DA was a bit over 7000' - which is the actual physical elevation of our home field.  We requested a southeast departure and, after take off, tower asked if we wanted to climb over the airport to clear the ridges.  I appreciate that they offered, but with the two of us and full fuel and about 85 pounds in baggage it wasn't needed.

 

[midlifeflyer]

1 hour ago, Ross Taylor said:

So, we just returned from our trip to Truckee-Tahoe yesterday evening.  While on this trip, I wasn't keeping up with the thread and am just now seeing a question about our high altitude leaning.  I lean to max RPM during run-up, then dial in (richer) two turns.... but that's just me, for starters. 

 

No, it's not just you. Although the number of twists can vary slightly with the make/model (you learn what works for your airplane), this is the way leaning for takeoff is taught for normally-aspirated engines by instructors in Colorado (at least in 20 years of flying,  and teaching there I haven't come across one who didn't teach it this way).  

FWIW, this is a copy/paste of a write-up I did years ago.

Leaning for takeoff at high density altitude (normally aspirated).

If you are operating for the first time in a high density altitude environment, local instruction is always your best bet because it's not just about the effect on power. That said, this is the method generally taught at flight schools in Colorado.

Target leaning for max power is done at runup power. This is for two reasons other than it just works for all but a very few make/models.  One is that leaning at full power can be hard on the brakes of higher performance engines; the brakes might not even hold in some. The other is that, a constant speed prop will act like a fixed pitch one when set at runup rpm so you an easily see the changes on the tach..

When you are ready to do the run-up:

1. Enrichen the mixture (you should have leaned it for taxi, so you need to enrichen it for the run-up power demand). You don't really need to go back to full rich at this point, but there's no harm in doing so until you learn about where to set it.

2. Go to run-up power.

3. Lean. You will initially see a rise in RPM as you reach best power and then a drop. When you see the drop, enrichen back to peak. 

4. Enrichen more. On airplanes with a vernier mixture control, 3-4 twists will do it. Without a vernier, about 1/4-1/2" tends to take care of it. The enrichment is for 2 reasons:  approximate the additional power  requirements for takeoff and for engine cooling.

In most airplanes, this will be exactly what you need for takeoff. Many instructors I know stop here but bear in mind that this is an *approximation* which needs to be cross-checked, at least until you have learned  the run-up technique works for your airplane.

The cross-check should be done at full power. It does not take long a few seconds at most. If the brakes will hold, you can do it while still at the runup area, or you can wait until the runway just before beginning the takeoff roll. I usually do that final check on the takeoff roll. The exact check varies. It's often simply getting expected rpm but you might have a table of fuel flow targets for takeoff to measure against. If you know your target best power EGT, great. Personally I have never had to move the mixture more than a 1/2 twist or its equivalent. 

Finally, remember that this isn't brain surgery. Look at your POH - that instruction to lean "above 3000' is a pretty good indication of how much leeway is built in.
 

 

 

[kortopates]

The above is probably the best you can lean a NA aircraft for takeoff without an engine monitor, but with an engine monitor we can do far better about guessing how much more to enrich or how lean to keep it using the target EGT method described in the referenced presentation below. Keep in mind a great many aircraft are already on the lean side at takeoff at sea level, with corresponding high temps in initial climb.  So if you're possibly one of these consider leaning to what is your full rich EGTs at 1000' msl or maybe a bit higher rather than sea level; especially if you don't have low obstacles to be concerned with. But regardless, if you know how to lean by max rpm, tune your leaning using the Target EGT in the  take off run and after you have cleared low obstacles to ensure max performance without the guess work. If your just learning how to lean for high DA, you may prefer to give yourself some additional time to adjust by holding the brakes on the runway. See the Target EGT presentation here https://www.advancedpilot.com/tech.html 

With the vast majority of trainer rentals having engine monitors these days having one and knowing how to use it should be more widespread. But what I see in my area may not be representative of the entire country. 

Edited July 16, 2019 by kortopates

[zaitcev]

On 7/10/2019 at 9:11 AM, Bob_Belville said:

• KCUT Custer Co. SD (Mt Rushmore) 5602' elev;  5500' r'way
• KCOD Yellowstone RGNL WY             5102            8200
• KWYS Yellowstone (West) MT           6649            8400
• KMMH Mammoth Yosemite CA        7135            7000 in the shadow of high peaks to the West
• KTPH Tonopah NV                              5430            7100
• KCDC Cedar City RGNL                      5622            8600
• KCEZ Cortez CO                                   5918            7200
• KSAF Santa FE NM                              6345            8300

I'd be very interested in a report about a few of these places, too, especially Yosemite fields.

I never landed at Tonopah, but I drove in 4 years ago. It was an absolutely hole in the wall airport. However, there was someone living on the field, running what you may consider an FBO. As I was taking my tour, a King Air landed with UPS parcels and UPS workers unloaded it into delivery trucks. Absolutely do call ahead to find out if they have fuel. When I fly in the area, I always go direct from Reno to Cedar City, or Hawthorne to Cedar City.

Cedar City is fabulous. I very much prefer it to Bryce.

For some reason, I could never land in Cortez, always ending in Farmington instead. Every time tell myself "never again".

Santa Fe is an okay airport, but it is stupid expensive. A gallon of 100LL can easily be $7+ there. I flew there a lot when I lived in Albuquerque, but now I always avoid it. You can refuel in Las Vegas, NEW MEXICO (KLVS)

As far as mountain flying goes, it's way overblown. Sparky's Bible is needed when you do real back-country. Otherwise just make sure to lean to best power before takeoff and make your preflight planning properly, including climb-out routes, not just runway length. The biggest thing about mountain flying is the weather. But then you aren't screwing with thunderstorms on the plains either, right? It's no different in the mountains: don't screw with winds and clouds and you'll be fine.

I found that flight following is usually available if you just stick to 11.5-12.5, if you want to go VFR.

Edited July 20, 2019 by zaitcev

[Danb]

Bobby nice trip , I’ve followed your progress a few times a day with jealousy, boy you must be tired, hopefully your grandson got great memories? DB

[Danb]

10 hours ago, Danb said:

Bobby nice trip , I’ve followed your progress a few times a day with jealousy, boy you must be tired, hopefully your grandson got great memories? DB

Bob also followed your trip home,  welcome. I gotta get a life. Nice job, I’ve landed at Snipes a few times luckily you kept trucking 

.

[CaptainOveur]

On 7/11/2019 at 3:45 PM, Bob_Belville said:

Thanks for the vote of confidence, Paul! I can learn form anyone and I appreciate all the advice from all those who took time to comment.

My current plan has moved the Eastbound portion to the south picking up Yosemite and an aerial tour of the Grand Canyon  (not depicted) so I'll skip Denver but enjoy Gorilla's hospitality in OK.

 

• Thursday July 18 Minuteman to KPWK (Chicago) eat at Cafe Beograd.need car, room

• Friday July 19 KPWK to KMSN, Holiday Inn Madison WI 

• Saturday July 20: formation flight KMSN-KOSH Camp with Mooney Caravan in “North 40”

• Sunday July 22 Caravan Wisconsin Fish Fry @ Caravan tent

• Monday July 22 MooneySpace pizza @ Caravan tent 

• Wednesday July 24 Brats & Brew at Aspen Avonics

• July 22-28 AirVenture … Air shows every day & 2 nights, war birds, antiques, exhibitors, workshops and seminars... 

• Day 1 Monday July 29 KOSH to KCUT (Custer SD) with brief stops in MN, ND, NE. camp on airport overnight

• Day 2 Tuesday July 30 rental car to Mt. Rushmore then flight to KCOD Yellowstone. Fly over/through Yellowstone land KWYS West Yellowstone. Camp there and rent car for tour through the South Loop of the park - Old Faithful, etc.

• Day 3 Wednesday July 31 KWYS to KDLS (The Dalles OR - Columbia Gorge with stops in Idaho Falls ID, Pasco WA. The leg from Paso to The Dalles follows the Columbia River.

• Day 4 Thursday August 1 The Dalles OR to KMMH Mammoth/Yosemine CA. Scenic flight passing Mt. Hood, Mt. Jefferson, Mt Washington, Three Sisters Mts, Crater Lake, Klamath Lake/Rapids, Mt. Shasta, .

• Day 5 Friday August 2 KMMH  to KPGA Page City AZ with stops in Tonopah NV and Cedar City UT. 

• Day 6 Saturday August 3 KPGA to KSAF Santa Fe NM with aerial tour off Grand Canyon and stop in Cortez CO. (Glen Canyon, 4 Corners) 

• Day 7 Sunday August 4 KSAF to KSUS St. Louis MO with stops in Amarillo TX, Elk City OK, Independence KS

• Day 8 Monday August 5 St. Louis to Minuteman with stop in Dayton OH

 

What a cool adventure and cool thing for your grandson to pass along to his own grandkids someday!

 

 

[Bob_Belville]

On 8/5/2019 at 5:02 PM, Danb said:

Bob also followed your trip home,  welcome. I gotta get a life. Nice job, I’ve landed at Snipes a few times luckily you kept trucking 

.

Thanks Dan, you're right about the tired! But great adventure.

Spent today loafing... Nancy and I will fly home from MA tomorrow, D.V.