Simviation Forums

How can I adjust the trim on a Jet?  most of my jets, specially the bigger ones in my FS2004, tend to point the nose up too much when cruising at high altitude, any altitude for that matter.

Any help will be much appreciated.

John.

The default settings are on the numeric pad (1 and 7 if I remember correctly but I changed mine). If you go to settings and look at keyboard assignments you'll be able to check. Also remember that changing your engine settings will affect things as does burning fuel

I thought it was normal for a jet to have a slight nose up position when cruising....oh well...

.mic

You will know if the nose is TOO high by observing your "Rate of Climb" indicator during the cruise.

If it indicates that you are climbing during your selected cruise altitude, and at your selected cruise power, then you need to trim the nose down slightly with the "Trim Wheel" until your rate of climb indicates zero.
(Auto-pilot normally does this for you).

Then re-adjust your power setting.

As Ozzy says, any change in power will also affect your pitch, which you will have to correct manually.

F....G-BPLF... 8-)...!

You will know if the nose is TOO high by observing your "Rate of Climb" indicator during the cruise.

If it indicates that you are climbing during your selected cruise altitude, and at your selected cruise power, then you need to trim the nose down slightly with the "Trim Wheel" until your rate of climb indicates zero.
(Auto-pilot normally does this for you).

Then re-adjust your power setting.

As Ozzy says, any change in power will also affect your pitch, which you will have to correct manually.

F....G-BPLF... 8-)...!

Hey Fozz.

What ever happened to low and slow??

Zaphod.

You will know if the nose is TOO high by observing your "Rate of Climb" indicator during the cruise.

If it indicates that you are climbing during your selected cruise altitude, and at your selected cruise power, then you need to trim the nose down slightly with the "Trim Wheel" until your rate of climb indicates zero.
(Auto-pilot normally does this for you).

Then re-adjust your power setting.

As Ozzy says, any change in power will also affect your pitch, which you will have to correct manually.

F....G-BPLF... 8-)...!

Hey Fozz.

What ever happened to low and slow??

Zaphod.

Hello Zaph... ...!

It's always low and slow with me... ...!

The nice thing about "Low and Slow" is that you have time to take in the situation and make corrections in plenty of time...

(As the Bishop said to the Actress).

I apply the same techniques to my little Cessna 150...
...and she loves it...too... ...!

F.... ... ... ...!

It's not only the trim that affects this, some models aren't quite right and they will naturaly cruise with a high nose. Dropping the nose useing the trim will just make you go down.

John_HR,

Worry ye not - there is a tweak to fix this. As indicated, most jets are slightly nose-up in cruise - about 2-3 degrees is normal. If it's higher (or indeed lower), you can adjust it. First, back up your aircraft.cfg, then open it in Notepad. Look for the [flight_tuning] section, and the first entry is normally:

cruise_lift_scalar=1.00

This value increases or decreases the lift at cruise. Excessive nose-up usually means not enough lift, so by increasing the value, you increase the lift and the nose correspondingly drops. Play around with it until it's right for you - figures up to 1.50 aren't uncommon.

Of course, to raise the nose, reduce from 1.00. (My Posky 747-400 value is set at 0.6.)

..Micro...

The name "Microlight" and "Posky 747-400" never seems to sit in the same category, lately.... ...!

F.... ...!

P.S. ....remember the Cosmos "Flex Wing" Avatar?.......LOL... ...!

John_HR,

Worry ye not - there is a tweak to fix this. As indicated, most jets are slightly nose-up in cruise - about 2-3 degrees is normal. If it's higher (or indeed lower), you can adjust it. First, back up your aircraft.cfg, then open it in Notepad. Look for the [flight_tuning] section, and the first entry is normally:

cruise_lift_scalar=1.00

This value increases or decreases the lift at cruise. Excessive nose-up usually means not enough lift, so by increasing the value, you increase the lift and the nose correspondingly drops. Play around with it until it's right for you - figures up to 1.50 aren't uncommon.

Of course, to raise the nose, reduce from 1.00. (My Posky 747-400 value is set at 0.6.)

If all your other numbers are good (like adequate cruise speed at cruise settings.. or the proper airspeed when climbing at a known vertical speed... or the proper vertical speed when descending).. you  DO NOT want to mess with flight tuning at all, especially cruise lift. It will mess up the other numbers and you'll end up chasing 5 tails.. What you want to do is change the wing incidence in the geometry section.  Increasing the incidence lowers the nose.. It's the angle at which the wing cord is, to the fuselage, longitudinally.

Interesting point there, Brett, and if we were talking about FS2002, I'd agree with you - indeed that's how I used to fix it in that sim. But it doesn't appear to work with FS9 (hasn't for me anyway). Adjusting the cruise lift figure is specified in the aircraft container SDK for this, and while I agree also that all things being equal, you shouldn't need to do this at all - but sometimes you have to as all FDEs are not created equal.

Also, it's either that, or start fiddling in the depths of the .air file - something that's best avoided at all costs!

Ah, that Cosmos flex-wing...

Oh my..

Checking/adjusting your aircraft's weight and balance might help if the pitch is excessive... some of the a/c I've downloaded have in some instances been overweight by as much as 60k lbs, with much of that weight well aft of the center of gravity.  

Two ways to check and adjust w&b: if you're in flight mode go to the menu bar, click on "Aircraft," and then click on "Fuel and Payload." Also, on the "Create a Flight" screen there's a "Fuel and Payload" button that'll let you adjust these as well.

Thanks all you guys/gals,  I'll start tinkering around a bit, see what I find and maybe I ca fix it.  By the way, when I say "nose up" I mean its 10 degree up or sometimes even more, amd I know thats way too much.

Thanks again, I hope I find some time this weekend, to play around a bit.  :)

John.

Brett,

You make a very fair point about the SDK authors!

You're of course also right about the danger of random tinkering with isolated values in the FDE. One of the issues I guess is that there are too many developers that are so keen to see their creations 'out there' that maybe not enough care is taken over the FD. This is why it's important to get the balance right between all of the lift, drag and thrust inputs - and cruise lift is just one component of that. When it's part of a holistic design though, it's a powerful tool.