Just inquiring about what people have “real world” experience in with summer time heat and higher altitudes. Looking at a 6300’ elevation and 80 degree temps with pressure at 30.10.

I can do the numbers, but just curious if there are any “insider” tips, gotchas, techniques. And to throw a twist….that strip could also be water in those same conditions (so for you float flyers as well).

I flew in the Idaho back country in August 2016 and landed at some high elevations such as Cold Meadows (U81) at 7,030 ft. It was in the morning about 9:00 am and the temperature was somewhere around 70F so the density altitude was about 9,100 ft. My MX-7-180's weight was about 2,200 lbs. Takeoff distance was about 1,400 ft and climb with a 180 hp O-360-C1F carbureted engine was anemic at about 300 fpm. Cold Meadows has a 4,550' x 90' turf/dirt airstrip so the takeoff distance wasn't a problem. If you are going to land at short airstrips in high density altitude conditions, make sure that you can take off again or plan to camp overnight until cooler morning conditions. Takeoff distance in my airplane is about twice the distance of landing at high density altitudes.

Because the air is so much thinner at high density altitudes (less lift), it's good to be careful about steep banks at low airspeeds on landing or circling. To avoid a low-altitude stall/spin, don't apply any yoke back pressure to keep the wing unloaded and accept the altitude loss in a steep bank, such as a canyon turn. A slower canyon cruise speed, flaps and full power are your friends in that situation. Having a steep, stable approach to clear obstacles, slow final approach airspeed to shorten landing distance, and a well-identified abort point are important. Many of the back country airstrips are one-way in and out with high terrain so go-arounds are difficult or impossible.

Install an AOA and fly it. Makes everything the same till you get to the ground. Doesn't help the need for longer runways or the less vertical speed on climbs though.

I had my MX-7-180 for a year out in Colorado. With just me and full fuel, I would take off around 8000ft DA and climb up to 12,000ft pretty generally holding 700-500 FPM on the way up. With two people and full fuel at 9000ft, my takeoff roll was around 1000ft and climb was about 500 FPM. For my plane, I liked to climb at 200-300FPM while going as fast as possible with the energy left over to cool my engine. When you have 20 miles to clear the ridge, no need to try to climb at Vy and get too hot.

My friend with an M-7-235 was passing 10000ft climbing at 1000 FPM so the 235 definitely shines at higher altitude.

My advice is to make sure your prop low pitch is correctly set up so with the brakes set and full power applied, you are “off the governor.” Depending on the installation, you may be 50-100RPM below your actual redline, then as the airplane accelerates the prop unloads and the governor takes over at the redline. The benefit to this is being able check your static RPM and potentially lean for best power at the higher elevations. If your prop is set at a finer pitch than it should be, you will always show you’re making full power but won’t know if you actually are until you see your climb rate.

My final high DA tip is the Surefly SIM won’t do you any favors using their variable timing if you are trying to climb in high density altitudes. I went back and forth with them and finally put mine back to fixed timing and got much better performance.

Not Maule specific, but something to keep in mind for higher DAs: remember to keep the mixture pulled out, even on takeoff and landing. Your mixture should be correct already on approach, and you should lean for engine performance during your run up, but if your primary instruction was like mine, then it's habitual to "mixture, full rich" during those phases.

Years ago, when I was a fresh from the flatlands pilot, I had a most exciting takeoff from Dyer, NV (2Q9) on a hot afternoon in early July (DA was likely 8-10k) when my instincts in response to my engine not making full power on the takeoff roll was to push mixture all the way in. The engine just about died and those wires on the departure end got quite a bit closer than I'd like before I figured out what I'd done...