Bouncing needles

[II./JG1_Krupinski]

I've been playing with this and have found a few things.

First, I don't have a lot of CoD cockpit time so take this with a grain of salt. I use full real settings as the starting point. and using the German France freeflight quick mission/

I first noticed the shaking on my first flight, which happened to start about 10 seconds before I lubricated my wind screen for a total of 10 seconds flight time. Okay, bad engine management.

Determining the best manner to manage my engine I still noticed the shake, even with oil temp maintaining between 40 and 60 C and water a little above 80C. Tooling around I am setting the engine up @ 1.2 ATA and about 2100-2200 RPM.

I was able to fly to England and back. Over England, I was able to see no shake for about 30 seconds. What I had done was dove to about 800 meters ASL. So a couple things were at play here, lower altitude and faster airspeed. The shaking returned as i climbed and slowed. I thought it was speed at this point.

Starting another quick mission, I tried to tool around at a minimum 450kph. Still, shaking happened. Try this at lower altitude, its shaking.

All manner of tests using full real, I came up empty handed.

Finally giving up and not being able to take the shake, I turn of turbulence in the settings as a last ditch hope of finding what's going on. BINGO! no more shake.

So this shake that I thought was my bad engine management, seems to be caused by turbulence. I am going to test this more tonight.

[Space Communist]

Well I have only been in the cockpit of an aircraft once, a 60 year old Piper. Every instrument in that thing bounced around constantly, just as I have seen happen in many of the videos.

Sounds like this isn't the case with more modern aircraft?

[RAF74_Winger]

I've flown aircraft of similar vintage, but never seen the needles shake around like that, not even during aerobatics or heavy turbulence. There are restrictors in the inlet lines to all of these pressure driven (bourdon tube) gauges for precisely this purpose - besides which the accumulated fatigue damage to the bourdon tube would soon result in a broken instrument if it weren't present.

W.

[Buzpilot]

I would say that engines running at the best in CoD, even then, are somewhat broken.
Mixture don't get sufficient lean ?

[Space Communist]

Originally Posted by RAF74_Winger

I've flown aircraft of similar vintage, but never seen the needles shake around like that, not even during aerobatics or heavy turbulence. There are restrictors in the inlet lines to all of these pressure driven (bourdon tube) gauges for precisely this purpose - besides which the accumulated fatigue damage to the bourdon tube would soon result in a broken instrument if it weren't present.

W.

Interesting. Well I dunno what was up with this plane I was in then. Doing a brief internet search and finding some images I am confident the plane I went up in (which had very bouncy instruments indeed) was a Piper PA-17, if that helps.

Edit: I initially thought it was a J-3 but i was mistaken

[whipper1]

Was out for a pleasure ride in a Hurri the other night and all the guages were bouncing like crazy..to the point of being almost unreadable. I have 100's of hours in light twins (RL) and have never seen anything like it except in the Bermuda Triangle.

[Redroach]

Originally Posted by svanen

This happens when your engine starts running rough, it is very nice feature. The needle does not bounce when engine running smooth in a stable flight.

This, exactly this. I've been able to reproduce this, albeit more by accident, as I'm still learning...

I'm really amazed that those "guys who fly real aircraft with thousands of flight hours" don't get that.
But I don't worry there, 1C have their own flight testers. Some of these guys flew or fly the real thing(s), so I definately give more about them than about random internet "flight instructors".

Originally Posted by Redroach

This, exactly this. I've been able to reproduce this, albeit more by accident, as I'm still learning...

I'm really amazed that those "guys who fly real aircraft with thousands of flight hours" don't get that.
But I don't worry there, 1C have their own flight testers. Some of these guys flew or fly the real thing(s), so I definately give more about them than about random internet "flight instructors".

So next bug classified as irrelevant on this forum... If it is caused by shaking or turbulence, why the whole cockpit is not shaking? If you fly in plane and you fly into turbulence it is not just minor shaking, it is like someone is hitting you from different sides, you hear the sounds as different part of plane hit to each other. I don't see anything like that in CoD... I only see that needles are jumping like mad? But what is physically causing these jumps? Turbulence within each instrument, which is not effecting the plane as whole?

[Redroach]

Okay, maybe you have turned off the head bounce thingy, where it may be not as obvious, but:

I happen to be a physicist (for real, it's not just a random claim ) and the thing is that the engine has its resonance frequency just like anything else. So, if you have tuned your engine badly, it will be go into resonance, causing it to shake and vibrate. And, because the engine represents a large mass, it will shake up the entire airplane with it. This, in turn, includes cockpit instruments and, since the the instrument needles are allowed to move relative freely, inertia causes them to bounce as well.

Now this is less obvious in more modern cockpits, as advances have been made in mounting the engine(s) with dampening elements. The engines are designed to run more vibration-free, too and cockpit instruments, if not already digital, have also been improved, "decoupling" them from airframe vibrations in better ways. It's shouldn't be like 1940 anymore

I'm more and more amazed at the level of detail the developers introduced into CoD and it makes me sad that many of those details are, if not quite convenient, called "bugs" by some users. Don't get me wrong, there are bugs and there are quite a few, but CoD is NOT an arcade game and I really, really hope that Oleg, Luthier & co. stand by their philosophy in striving for realism - as this is the "perk" why the majority of players have fallen in love with the Il-2 line.

Originally Posted by Redroach

Okay, maybe you have turned off the head bounce thingy, where it may be not as obvious, but:

I happen to be a physicist (for real, it's not just a random claim ) and the thing is that the engine has its resonance frequency just like anything else. So, if you have tuned your engine badly, it will be go into resonance, causing it to shake and vibrate. And, because the engine represents a large mass, it will shake up the entire airplane with it. This, in turn, includes cockpit instruments and, since the the instrument needles are allowed to move relative freely, inertia causes them to bounce as well.

Now this is less obvious in more modern cockpits, as advances have been made in mounting the engine(s) with dampening elements. The engines are designed to run more vibration-free, too and cockpit instruments, if not already digital, have also been improved, "decoupling" them from airframe vibrations in better ways. It's shouldn't be like 1940 anymore

In reality, every turbulence has much stronger force effect than any engine and it is affecting whole plane and everything within it. Everything is shaking - pilots or passengers included.... In such cases the needles on instruments would be just "MAD" and completely useless which never ever happened in the whole flying history. Pilots heads is shaking more if going into the wild dive, whole plane is shaking like mad but pilots can still read the instruments. That's what they are trained for, read trembling(but not jumping) needle of instruments when their head is shaking like mad...

If it would only tremble (when starting, turning off, or dives on higher speeds) - OK... But right know it is just one of many little annoying "features" of this sim...