I’m a new user working my way through the Flight Training tutorials. One of the VFR modules requires you to climb from 6500 feet to 8000 feet and whatever I try, I can’t seem to do it.
I’m flying the Cessna 152 which according to the POH has a best rate of climb at around 75 KIAS/700 feet per minute. But I can’t get the plane to do this. As I gain altitude, the airspeed goes lower and lower and long before 8000 feet, I get the stall warning.
What’s the trick here?
Should I be leaning the mixture maybe? There’s been no mention of leaning in the tutorial so far but maybe they threw this in as a trick!
OK thanks, I’ll try this, But it’s a pretty cruel trick to throw this in without guidance on rookies who are still trying to figure out one end of the plane from the other!
No, you have to lean it more and more as you climb. A quick and dirty way to lean the mixture is to just pull it and listen until it starts to sputter, and then push it back in a bit until you hear your RPMs peak. Make sure your carb heat is cold while climbing (turn it on when idle on descent).
Please note that the 700fpm climb rate for the 152 is the maximum @ sea level, where you have the most horsepower available. At 6,000ft and depending on aircraft weight, outside air temperature and atmospheric pressure, the best rate of climb is barely above 400fpm and it reduces to less than 400 FPM at 8,000 ft.
And very importantly: In addition to leaning to ensure best power, from your description it sounds as if you are trying to maintain a set rate of climb and allowing the speed to decay. This is not the appropriate way to increase altitude. The appropriate way to climb is to apply full power (appropriately leaned) and raise the nose to get to the best rate of climb speed, which at 6,000+ feet is around 63kts IAS. You must then maintain that speed by adjusting the trim of the aircraft and accept that, as you continue climbing, the rate of climb will gradually diminish as the maximum horsepower reduces with reduced air pressure.
So bottom line: to climb from 6,500 ft., stick to about 63kts IAS and expect around 400fpm rate of climb likely reducing to less than 400fpm by the time you reach 8,000 ft. And unless you have auto mixture enabled, you will have to further lean the mixture as you climb.
The rate of climb gauge is used only as information; climbing is basically a matter of speed.
Here are the speeds of the C152:
Best glide speed 60 KIAS
Stall in landing configuration Vso 35 KIAS
Stall in cruise configuration Vs1 40 KIAS
Rotate Speed Vr 50 KIAS
Best angle of climb Vx 55 KIAS
Best rate of climb Vy 67 KIAS
Maneuvering Speed 1670 lbs. Va 104 KIAS
Flaps extended Vfe 85 KIAS
Max. Structural Cruising Speed Vno 111 KIAS
Enroute Climb Speed 70-80 KIAS
Approach Speed Vapp 55-65 KIAS
Never Exceed Vne 149 KIAS
Vx and the Vy are the most used during a climb. The Vx (55 knots) is the best speed to create the best angle to fly over an obstacle; for example to fly over trees at the end of the runway you are taking off. The Vy (67 knots) is the speed to get the highest altitude in the shortest period of time.
As for leaning the mixture, we do not basically lean during a climb, because the engine is working hard (like a car climbing a hill) and not leaning is keeping the engine cooler because of the rich mixture. When the cruising altitude is reached, then we lean to keep the appropriate air/fuel ratio. I agree though that leaning the mixture while getting at high alitude like 8000 feet is required.
By the way, during a hot and humid summer day, rate of climb decreases naturally a lot because the air is less dense; leaning the mixture is no help to get things back to normal.
I helped someone with this a while back. You need to lean the mixture. Give it full throttle and slowly pull the mixture back until the RPMs peak. Or push it forward. Whatever it needs to deliver peak RPM.
It is beyond comprehension why they decided to use the area around Sedona AZ for flight training, in a 152 no less. Beginner pilots have more than enough on their plate already with everything going on and to toss in high altitude performance issues in an underpowered aircraft with no prior instruction on engine management is indeed cruel and unusual. Honestly it makes me mad because I think they should be trying to make it easy to learn. Pick an airport at or near sea level, for crying out loud!
Quick postscript to this (and thanks again to all the helpful comments!) - looking around this forum, I see that mixture setting on prop planes in FS2020 appears to be fundamentally broken. Fix coming in Su7 (maybe…)
I also didn’t realize that auto mixture was an option in the settings (and is on by default). So if I manually lean the mixture mid-flight with the auto setting on, does it actually do anything?
There are eight lessons in the first set, seven in the second set, before you get to VFR. I’m amazed they wouldn’t cover leaning before VFR navigation.
