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Need trim-reset


MarcT-NL

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Eventually there will come a time that you just don't get the trim right again. The shortest push to the left gets it left from center, the shortest push to the right gets it to the right of the center.

I think all virtual planes who have a trim, need a trim-reset binding.

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3 hours ago, MarcT-NL said:

Eventually there will come a time that you just don't get the trim right again. The shortest push to the left gets it left from center, the shortest push to the right gets it to the right of the center.

I think all virtual planes who have a trim, need a trim-reset binding.

Why? You always can see your trim position...

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3 hours ago, MarcT-NL said:

Yes and sometimes I just want to center it all with a push of a button.

...and sometimes i would like to win the lottery. But unfortunately...
I always find it interesting that people demand DCS to be as real as possible, but on the other hand then have such wishes 😆.

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Well that's nice. Let's just say that IF ED decides to make a trim-reset in the F5 and Mosquito and just make that one of the standard-features for every plane, just like they did in the P-51, the A-10C's and the choppers, and maybe some other planes, then you just won't use it. OK ? I wouldn't want to ruin your feel for reality.

I always find it interesting that people try to oppose someones whish while they have totally no disadvantage from it.

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10 hours ago, Terry Dactil said:

It is a propeller aircraft, so any time you change power or speed you need to set a new trim position.

That applies to jets too, at least that was my experience in T-37s, T-38s, RF-4s, (not the F-16A since it autotrimmed to 1 G), DC-9s, MD-80s, B-757s, and A319/320s.

10 hours ago, Terry Dactil said:

There is no 'center' position to reset it to

There is a "neutral" trim position in all three axis, just look at the trim indicators.

To @MarcT-NL, I'm finding the Mosquito requires about 2 units (tick marks) of nose down trim for a level cruise at a nominal airspeed of ~250+ mph (~2300 RPM and ~6 lbs of boost) at low altitude. Neutral rudder trim and slight right aileron (trimmed slightly right). 

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11 hours ago, Terry Dactil said:

There is no 'center' position to reset it to.

The position it had when you entered the mission. I don't expect the plane to behave neutral with this button. Just to get the trim in the starting-position.

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On 3/27/2022 at 8:54 PM, Robi-wan said:

There is a "neutral" trim position in all three axis, just look at the trim indicators.

To @MarcT-NL, I'm finding the Mosquito requires about 2 units (tick marks) of nose down trim for a level cruise at a nominal airspeed of ~250+ mph (~2300 RPM and ~6 lbs of boost) at low altitude. Neutral rudder trim and slight right aileron (trimmed slightly right). 

I find it odd that I need so much forward trim in the Mosquito. Planes are usually designed to cruise with the elevator trim at near neutral position. This is of course dependent on the current weight distribution and in the Mosquito the bay bombs shift the center of gravity backwards which requires nose down trim to compensate. During takeoff you want the tail to rise by itself, so trim is nose down.

However, I can’t find any situation where I trim past the “neutral” center position into the “nose up” side. Maybe during landing when I am too busy to notice?

The practical state of Mosquito trimmers is pretty good right now and I can trim her well enough to hop over and play navigator without going off course or lawndarting. So kudos ED :thumbup:

“Mosquitoes fly, but flies don’t Mosquito” :pilotfly:

- Geoffrey de Havilland.

 

... well, he could have said it!

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On 4/1/2022 at 1:07 PM, Bozon said:

However, I can’t find any situation where I trim past the “neutral” center position into the “nose up” side. Maybe during landing when I am too busy to notice?

I too am finding the persistent nose heavy (down) trim a bit of a puzzle. IMHO the Pilot Notes regarding configuration changes is less than enlightning. It would be more helpful to say something like at cruise with gear and flaps up at XX,XXX weight, anticipate slight/significant/2 units of nose down trim (in relation to neutral/centered). Or possibly Undercarriage down and flaps up ... Nose (slightly up/down from neutral) rather than this.

Mosquito trim changes.jpg

Using the instant action free flight scenario I tried a quick check of 1) slow flight with gear down holding altitude then 2) landing configuration descents with gear down, flaps ~15-20 and 3) landing configuration with gear down and full flaps. I set the RPM to ~2700 and from there only modulated the throttles.

Slow flight looks like it requires about 1 unit of nose down trim.

Slow flight gear down flaps up.jpg

Landing configuration with gear down and flaps 15-20 degrees...didn't require a change of the trim, and I had slowed down.

Descending gear down flaps 15-20.jpg

Adding full flaps didn't require any trim changes.

Descending gear down flaps full.jpg

This was a very quick and dirty check, not a rigorous flight test. I think this needs further testing, but my impression is the current trim model is not correct. 

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@Robi-wan are you sure that you don't have game flight mode checked, because i have to trim a lot when i deploy gear or flaps.

Mosquito in DCS behave just like in that page from manual.

But remember there is no neutral position in elevator trim, manual refers to trim acquired by pilot for level flight, so when pilot deploy flaps or gears will know what plane do.

And elevator trim for level flight will change with load out of the plane, when its empty or fully loaded, level flight trim will change.

 


Edited by grafspee

System specs: I7 14700KF, Gigabyte Z690 Aorus Elite, 64GB DDR4 3600MHz, Gigabyte RTX 4090,Win 11, 48" OLED LG TV + 42" LG LED monitor

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8 hours ago, grafspee said:

are you sure that you don't have game flight mode checked, because i have to trim a lot when i deploy gear or flaps.

Options.jpg

8 hours ago, grafspee said:

But remember there is no neutral position in elevator trim,

Of course there is a NEUTRAL trim position. When the airplane is rigged (installing & adjusting flight control surfaces) the erks follow technical guidance that specifically tells them to set the cockpit trim indicators to NEUTRAL and make sure the corresponding trim tabs are flush (trailing edge of tab aligns with the trailing edge of the tail, elevator, or aileron). 

There is a specific reason there is a big mark in the middle of the trim indicators. But if you don't believe me, how about actual Mosquito maintenance documents as published in this nifty book?

Mosquito Manual.jpg

Sorry for the quality, I took the pictures with my phone rather than scanning the pages. Read this regarding elevator trim...

Mosquito trim.jpg

For those that aren't sure what the highlighted text means, it means to look at the trim indicator on the left sidewall and set the trim to that mark between the O and S in the word NOSE. Okay, it's not a big mark, but it's pretty obvious to me. That is in fact the NEUTRAL trim setting. With this cockpit setting the erks would adust/fiddle with cables and pulleys to have the trailing edge of elevator trim tabs to be flush with the trailing edge of the elevator.

Mosquito nose trim.png

Likewise for rudder trim...that triangle marks where NEUTRAL trim is.

Mosquito rudder trim.png

And last but not least, the same applies to aileron trim.

Mosquito aileron trim.png

So please...everybody stop posting that there is no neutral/centered trim position. 


Edited by Robi-wan
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@grafspee, the overall practical behavior of the elevator trim is pretty good. The issue is that all the trim adjustments range is happening within a band that is quite deep in the “nose down” range, while we never reach the “nose up” side of the trim range.

The elevators of planes are usually designed to be “neutral” trim around some typical configuration/condition. The incident angle at which the horizontal tail is installed is part of this design. It is not a big issue since as I said, the trim does its job effectively - it is just odd, and takes a few more seconds to set up the plane for takeoff when starting cold, and we were wondering if this is how it is/was in the real plane.

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“Mosquitoes fly, but flies don’t Mosquito” :pilotfly:

- Geoffrey de Havilland.

 

... well, he could have said it!

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@Robi-wan  Ofc that all trims have neutral position in terms of trim tabs being aligned with trailing edges, but setting trim tabs that way do not guarantee that plane will fly straight.

 I just loaded mosquito with bombs and for level flight i need almost 2 notch nose down for level flight, i gues that if we were able to remove 20mm stuck  level flight trim would be neutral or something very close to it.

From mosquito manual, trim expected to be nose heavy for take off, so trim is modeled ok

wZxZtXJ.png

 


Edited by grafspee

System specs: I7 14700KF, Gigabyte Z690 Aorus Elite, 64GB DDR4 3600MHz, Gigabyte RTX 4090,Win 11, 48" OLED LG TV + 42" LG LED monitor

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50 minutes ago, grafspee said:

Ofc that all trims have neutral position in terms of trim tabs being aligned with trailing edges, but setting trim tabs that way do not guarantee that plane will fly straight.

To be clear, I've never said (or suggested or implied) that neutral trim would give you straight (& level) flight. But you posted this...

12 hours ago, grafspee said:

But remember there is no neutral position in elevator trim

And that is factually incorrect. You may know this, but readers that are not RL pilots might believe you. 

53 minutes ago, grafspee said:

From mosquito manual, trim expected to be nose heavy for take off, so trim is modeled ok

Having conducted RL flight tests, accuracy in one data point or phase of flight does NOT mean trim is modeled ok across the entire flight regime. It appears to be correct for takeoff, and perhaps cruise.

Respectfully, what @Bozon (I think) and I are trying to communicate, is that in this simulator the ONLY elevator trim positions we have seen are nose down. If you have experience some trimmed up situations with nose up trim, can you share those conditions? And a screen shot to show you have the nose trim up? Otherwise I speculate that this EARLY ACCESS flight model just might have a trim issue. If the Devs have first hand knowledge that the Mosquito always flies around with nose down trim, I'd be happy to hear about it. 

 

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Maybe in this  mosquito model you won't find config to to be able to fly with nose up trim range.

maybe you are right that complete FM will change trim, but look at spitfire, i don't use nose down trim in spit at all too, is is always nose up more o less.


Edited by grafspee

System specs: I7 14700KF, Gigabyte Z690 Aorus Elite, 64GB DDR4 3600MHz, Gigabyte RTX 4090,Win 11, 48" OLED LG TV + 42" LG LED monitor

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I'm scratching my cranium.  :confused:

I just spent some time on the Instant Action mission that attacks Abbeville. So with an internal bomb load, and the power set to ~2650 RPM / ~4-6 pounds of boost I was initially shooting for a climb at 170 mph, but accepted this slower speed. It still required almost two units nose down trim. That's just incredibly odd to me.

slow speed climb.jpg

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If you put more mass behind wings which provides lift and this is a case, it will make even higher pitch up moment which had to be corrected by heavy nose down trim.

But this could be easily corrected, by adjusting horizontal stabilizer angle of incidence, so the trim would be shifted to more neutral or even noes up range but designer didn't chose to do so.


Edited by grafspee

System specs: I7 14700KF, Gigabyte Z690 Aorus Elite, 64GB DDR4 3600MHz, Gigabyte RTX 4090,Win 11, 48" OLED LG TV + 42" LG LED monitor

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Quote

make even higher pitch up momentum which had to be corrected by heavy nose down trim.

/ nit pick mode ON

I think you mean the pitch up moment.  Momentum has a velocity component which does not apply here when the aircraft is in a stable condition.

Otherwise, I totally agree.  :thumbup:

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18 hours ago, Robi-wan said:

I'm scratching my cranium.  :confused:

I just spent some time on the Instant Action mission that attacks Abbeville. So with an internal bomb load, and the power set to ~2650 RPM / ~4-6 pounds of boost I was initially shooting for a climb at 170 mph, but accepted this slower speed. It still required almost two units nose down trim. That's just incredibly odd to me.

 

Re. trim requirements in level flight - Yo-Yo posted on 1st page of that thread why he modelled things the way he did:

 

i7 9700K @ stock speed, single GTX1070, 32 gigs of RAM, TH Warthog, MFG Crosswind, Win10.

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7 hours ago, Art-J said:

Re. trim requirements in level flight - Yo-Yo posted on 1st page of that thread why he modelled things the way he did:

 

Thanks for this.

I can't fault YoYo's logic if all he's working with are those charts. I have questions about the testing used to arrive at the data chart for DZ294. Meaning, DZ294 was a NF Mk II tested by the Royal Aircraft Establishment Farnborough. YoYo chided another poster about using a forward CG setting as being "not in normal flight" when according to one of his charts, 17000 pounds = 25.4 is actually pretty close to a typical operational weight for a NF Mk.II. 

DZ294.jpg

Tare (empty) weight and typical operating weight for a Mosquito NF Mk.II (DZ294)

F II tare weight.jpg

Perhaps he has data for a FB Mk.VI with weights somewhat higher...

FB VI tare weight 01.jpg

FB VI tare weight 02.jpg

Be that as it may, there are other reference documents out there (the Mosquito Manual shown in a post by me above) that specifically adresses rigging the flight controls AND what pilots should expect to see in the cockpit (i.e. the cockpit trim indications). I knew I had read this a long time ago, but couldn't pin-point it as I thumbed through the book (Homer Simpson D'oh moment)

So I posted this earlier to show there is in fact a NEUTRAL elevator trim position.

elevator trim adjustment 01.jpg

But if you keep reading on the top of the next page it continues...

elevator trim adjustment 02.jpg

My conclusion? This field document leads me to believe specifically that in cruise flight the trim INDICATOR should be zero or slightly nose down. Who are you going to believe? But clearly it's not my sandbox. 

[EDIT] Which is essentially validating your position based on the videos where it should be, and the guys that made excuses about it being a museum airplane and not combat weight/loaded are full of hot air.

 

 


Edited by Robi-wan
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