Simviation Forums

I can never get non turbo planes near theit service ceiling. Last night was flying the maule somewhere in the european mountains and could not get it above 16,000'. At around 14000 I had to climb at 100' per minute to keep from stalling. manifold pressure was about 18 went down to 15 at 15800. the ceiling for the maule is supposed to be 20000. Today I am flying the new cessna 310 from brett and alrot, take off from Denver flying to Aspen and I have trouble clearing the mountains. Same thing manifold pressure and airspeed drops at roughly 15000 ft. I have the same issue with the baron which has a ceiling above 20000. Never got close to that. I keep automixture on because i dont really understand EGT and dont know when to adjust. If someone would tkae time to explain that i would appreciate it but my main concern is what i am doing wrong that i cant reach the altitude that the aircraft is supposed to be able to attain.
Thanks in advance for any help, trflyman.

You're probably not doing anything wrong...

A Cessna 310 isn't really flyable above 15,000msl. And since it's not pressurized, you can't go above 13000msl without oxygen.

These planes are happy at about 8,000msl.

You can nurse one up near its ceiling to get over weather or something like that.. but like you're seeing.. it's flying on the edge of stalling, at 100fps. And unless you find a tailwind.. you might be tracking across the ground at less than automobile highway speed.

I've gotten my 310 up to 18,000msl... with careful mixture/prop management.. and there is a short-coming in the MSFS flight model that makes it more difficult and time-consuming than it should be. But that's OK, because these planes are meant to be flown where the pilot can breathe without plumbing up his nose..

Denali Base Camp scared me away from flying pistons above 8000

Why do they not just put the service ceiling at 13000 or 15000 instead of 20000 and above. Its hard for the pilot to be in service if he is passed out. Does service ceiling just mean the altitude that the aircraft will start to crumble due to pressure?  

An aircraft is only required to produce 100 fpm climb when at it's service ceiling at the time of manufacturing.

In the real world you'll always lose manifold pressure as you climb. On average, you lose 1" manifold pressure for every thousand feet. Eventually as you climb the throttle will be maxed out. You would then start to lean the mixture to get max performance out of the climb up until the service ceiling.

Of course, as planes age in the real world the odds of actually obtaining the service ceiling are marginal at best. Other variables also play a role such as humidity, temperature, weight, etc.

Are you climbing at Vy?

Are you climbing at Vy?

A little known fact is that Vy will actually decrease as altitude increases.

Are you climbing at Vy?

A little known fact is that Vy will actually decrease as altitude increases.

True.. and Vx increases.. and they become effectively the same airspeed near the ceiling..

But for the purpose of learning about high-altitude climbing in a non-turbo-charged, piston airplane... the important thing to remember is that TRUE airspeed increases.

V-speeds can be referenced by KIAS, no matter what the altitude (or density altitude), because the pitot-tube "sees" the same effect that the wings see. But what's important to remember; is that as the difference between Vx and Vy lessens... so does the difference between Vx and Vstall. If you fly Vy at high altitude, you'll end up teetering on the verge of a stall.. and considering you'd be doing that for quite a while.. I'll point out again, that flying near the ceiling is a theoretical thing only. It's inneficient, counter productive, stressfull... and unless you find a nice tailwind.. the headwinds at those altitudes could have you flying backwards

Are you climbing at Vy?

A little known fact is that Vy will actually decrease as altitude increases.

That was going to be the next question, but you beat me to it. It also changes with weight as well. Unfortunately most FS aircraft don't come with performance charts and only list one speed for Vy. For most light GA with lower ceilings, the variation is usually within 10 knots or so.

If I had to take a stab at it, I'd say that if your a light GA aircraft, decrease Vy by 1 KIAS per 1,000 ft. That'll at least get you in the right park.