VC10 autopilot

[forthbridge]

Just got round to reinstalling (cleanly) my VC10 fleet

However, and I am banging my head of the wall here..... :brick: I cannot get the autopilots to operate correctly no matter what I do.....

As the '10 is a favourite, I've installed it several times with absolutely no problem, however after installing and rebooting, and selecting the aircraft the standard (IE after a default) way, when I engage the autopilot, it all works - except altitude (IE use the datum adjust to alter pitch. Even if I settle the A/C manually into level flight, when I engage the A/P, it will hold (give or take) altitude as long as I quickly select a zero climb/descent rate. As soon as I move the selector, even to sub 500 fpm figures, the tail pitch starts going wonky, giving negative pitch and the plane starts to dive. It then initiates a climb which is then to pot as the speed has increased in the dive, etc etc basically giving a yo-yo effect. Anyone any suggestions?

:brick:

[Garry Russell]

Hi Jim

Is your load and CG within limits?

Garry

[forthbridge]

HI Garry,

Yes, I've tried various combinations. Generally I load about 40% fuel for ambling about, but at any weight on any model, I get the same result. In my experience the VC10 autopilot is very 'robust' in operation, so I'm perplexed.

[forthbridge]

Just had a sortie from Leuchars. Default payload and 90% fuel. At 1500AMSL I retracted flaps, IAS was 215 knots.Using the pitch at about 2.5degrees, maintained climb to 2500AMSL and 250KIAS. Engaged auopilot which then proceeded to disobey me (again).

Using throttle, A/P on/off and pitch, I managed to keep her in the air, and at 224 KIAS and 500 feet engaged autpilot again. It took me down to a Tonks-in-his bathing costume 35 feet above the sea, and LEVELLED off. (I had the datume set to +700FPM although the A/C descended....)

At this perilously low altitude, the datum adjust set itself to zero, so I tapped it up to +200 FPM. The aircraft climbed to 90 feet, then descended back down to 33 feet and levelled off.......

[DanKH]

I had something like that a while back, but bugger me if I can remember what was wrong....

Some wrong path-reference as I remember, and had to do a few edits in the cfg-files...

But I'm on FSX. On FS9 doing "what you're told" shouldn't place anything wrong.

You have of course downloaded the latest and greatest files from DM's site right?

[forthbridge]

Hi Dan,

All latest from DM's site. Something ain't quite right.... Even when the aircraft was trimmed to climb, it was sinking (IE pitched to correct climb) - with the speed dropping slowly. Increasing throttle merely made the pitch reduce and sink rate increase.

[DanKH]

And you're on FS9?

[Garry Russell]

What flap settings are you using?

Garry

[TSR2]

Is this not the old missunderstanding of how the VC10 AP works? I can't remember the detail, but recall similar questions when she was released... all those years ago!

[robbie]

Hi Dan,
You're right, there was a problem with the VC10 hunting +/-500 ft/m around the selected altitude, didn't happen to everyone though, I have the same fault, and a few other people,using the new Caravelle model.
I remember the exstensive posts at the time, but bugger me also, I can't seem to locate it now, I don't fly the 10 for that reason.
Robbie.