Notchy pitch trim?

[Deano87]

Hey all,

 

I'm loving this module, everything feels so analogue and alive.

The only issue I'm having at the moment is that the pitch trim seems to feel very notchy and imprecise. I tap nose up trim.... nothing happens, tap it again.... nothing happens... tap it a third time and suddenly it seems to click over to the next notch and I get a load of trim change all of a sudden, It makes the aircraft really difficult to trim out at times.

I've actually sat on the ground and watched the stabs from external view, you can actually see them mirroring the above behavior. I can give it taps of trim in either direction and most of the time the stab doesn't move, and then when it does it moves a BIG step to the next trim "notch".

Is this some idiosyncrasy of the IRL Mig-21s trimming system or some weirdness in the sim?

[Maxthrust]

I was wondering about this as well, however, large trim steps help levelling the aircraft at supersonic speeds. Combined with the rather fast trim rate, trimming for a speed that falls between the “notches” is not possible. Fret not though as we are not trying to match our speed say, with a tanker. 
 

It also helps to think the trimmer as the ultimate AoA selector. Maintaining altitude or desired ascend/descend rate is done by throttle input. For instance, 5 to 7 units AoA is recommended for best rate descends. Likewise the approach profile requires 7 to 9 units for initial approach and 11 to 12 units for the short final. Resulting speeds are just a function of the current aircraft weight and the air density.

[Deano87]

Hi Maxtrust, Thanks for your reply.

 

You maybe misunderstood my point. I'm not really looking for advice on how to fly around the issue, I more want to know if its realistic behaviour to the Mig-21 as I've never flown an aircraft (either IRL or virtually) with electric trim that behaves this way.

Looking at the issue more closely it seems as though there is a time threshhold which the trim button is required to be pressed in order for the stab trim to move, once that threshhold is passed the trim starts moving, however it will then continue moving for roughly 1/3rd of a second even if the trim switch is no longer being pressed. This is what causes the relativly course trimming feel. It also means that a lot of quick dabs of trim do not get registered at all. And when it does register it will just move to the next 1/3rd of a second step.
 

I have a difficult time believeing this is realistic, and It makes trimming - specailly while flying formation - a real chore.

 

Could we please get a "simplified" trim model where the stabs move as soon as, and for as long as the trim switch is activated. Make it a custom setting if you want. It would make the aircraft much nicer and more natural feeling to fly. IMHO.

 

I've made a short video to show the problem.

 

 

Edited December 26, 2020 by Deano87

[Maxthrust]

I agree with your observations, and I would have preferred if there was no or smaller delay between the trimmer switch activation and corresponding stabilitor  movement. 
 

Solution to your issue would also a require smaller trim step per each trimmer “click”, however this idea was shot down by the devs long time ago.
 

Having flown the -21 for a while now, the trimmer works pretty well for me and I don’t have any issues with flying the plane level or in a formation.
 

 

 

 

[rossmum]

I asked Dolphin about this a while ago, and he gave the impression that it's how the real thing behaves - that trimming hands-off is exceptionally difficult and you're almost always maintaining a little pressure on the stick. I haven't handled a real 21, but I had similar impressions from aircraft I have flown with electric trim systems, so it wouldn't surprise me.

[Deano87]

On 12/28/2020 at 12:09 AM, rossmum said:

I asked Dolphin about this a while ago, and he gave the impression that it's how the real thing behaves - that trimming hands-off is exceptionally difficult and you're almost always maintaining a little pressure on the stick. I haven't handled a real 21, but I had similar impressions from aircraft I have flown with electric trim systems, so it wouldn't surprise me.

 

It surprises me that the trim would be so course as for one notch to easily register on the G-meter though! But if that's the way it is! 

[CoBlue]

On 12/28/2020 at 1:09 AM, rossmum said:

I asked Dolphin about this a while ago, and he gave the impression that it's how the real thing behaves - that trimming hands-off is exceptionally difficult and you're almost always maintaining a little pressure on the stick. I haven't handled a real 21, but I had similar impressions from aircraft I have flown with electric trim systems, so it wouldn't surprise me.

Then he would have implemented it 5 years ago, it was not so sensitive before.

 

The trim is way to sensitive.