Can the vintage auotpilot be used for climbs and decents?

[BraselC5048]

Reading the manual, the autopilot for the l-049 seems pretty darned primitive. I mean, I'm used to vintage autopilots; pitch hold, heading hold, altitude hold and maybe the ability to turn. The problem is that, as far as I can tell, the vintage autopilot isn't really up to pitch hold. From reading the manual, it seems that the aircraft must be properly trimmed for straight and level flight first. But what if you intend to climb or descend? I don't 'think' it's possible to trim hands-off for anything other than straight and level, and it seems (from reading the manual) that changing the elevator setting for a different pitch than 'level' changes the absolute position of the elevator, rather than desired pitch, and as such, for anything other than level, would result in continuous nose up or nose down input until either than plane stalls or control is lost.

Hopefully I'm wrong, and either an aircraft can be trimmed for non-level flight, or the elevator control affects pitch, not elevator position. Also, does rudder and aileron trim need to be applied before engaging the autopilot? Also, it seems you need to manually re-trim the aircraft every time power is changed?

[Aymi]

It does work, the elevator AP control is a pitch command. You enter the somewhat desired pitch and the plane will hold it.

Thanks to how the wing works, it gets harder when you want to maintain level flight. At first you will have high alpha. But since you are flying straight instead of climbing your speed will increase. And speed + alpha induce lift so you'll start to climb again. Then compensate by lowering pitch command on AP for less alpha to get VS back to 0. But less alpha means less drag so you'll accelerate again... etc etc

This is why it is recommended to climb 200-300 ft above target altitude so you can make a descend to quickly gain speed and get to your optimum speed/lift/drag setting quicker.

[BraselC5048]

Well that's good to know. I'm just used to being able to set altitude hold on the autopilot and be done with it. (1940-50's era autopilots, of course. Modern ones are far to complex for my taste.)

On the flip side, I was quite surprised to find that it is not, in fact, turbocharged. Which means no intercooler flaps that are the bane of the flight engineer's existence. Without having to deal with that, and having a 4-tank l-049 (not even a 6 tank l-749!), instead of a 9 tanks with a 6-7 step fuel usage/crossfeed sequence, the flight engineer's workload seems pretty small. Which leaves you time to deal with the world's worst autopilot. (Wish I had the option of a 'modern' c. 1950 autopilot with it's ease of use.)

[Lufthansa 380]

Well, I find it easier to use the pitch trim to control my VS or hold an altitude, with the pitch hold mode engaged. After you get used to it it gets the job done, you just really need to keep an eye on it when adjusting power or levelling off. This autopilot has no ALT or VS hold mode, it's all old school and manual. I find that at 32" manifold and 2300rpm for the climg I can easily maintain a +500 - 1000 fpm climb, dependign on the load, of course. When levelling off at your flight level you need to constantly adjust the rim as you speed up.