Hi all, I’ve got a dumb question re: setting the trim wheel to the “take off” position. If my memory serves correctly (it’s been a few years since I’ve flown), if you do that in a cessna 172 it sets it up for the proper position so that your plane basically flies itself off the runway at 60 or 65 knots.
In MSFS this seems to be absolutely, completely broken. Flying along with the trim in take off position results in the C172 cruising at about 110 knots or so. I also tried to trim the Baron 310 (which I’ve never flow IRL) at the takeoff position - and when I took off in new Tour of Japan, it seems trimmed clear into the red zone - I was easily going 250+ knots. With gear down.
@SPowell42, not a dumb question, and not sure if this helps, but I have the command “Elevator Axis (0 to 100%)” set to one of my joystick buttons. It sets trim for takeoff and is also useful when you turn the autopilot off and it goes crazy. I use it often. Cheers.
Hi @FrankPilot1530, I guess my issue is that when I have the trim set to the proper “takeoff” position, the plane is trimmed for cruise, not takeoff. Does your elevator axis trick work for this? If it’s just setting the plane to the takeoff trim position - that isn’t helping - at least what I see is that the takeoff position is completely wrong.
Well, @SPowell42, for me, in both the C172 and the Baron G58, that command I mentioned sets the trim in the cabin, and also the HUD, to the take-off position and seems to work correctly. The aircraft will eventually leave the runway (at a rather high speed I must say) if you do not pull back on the stick/ rotate earlier at the correct speed, and for level cruise flight I have to manually trim. Anyway, just give it a go and see how you go. Cheers.
If you are using two assignments for the elevator axis, joystick plus an additional button, one cancels out the other.
If you use the button to e.g. pull the nose up a bit with the elevator instead of using elevator trim, it will immediately reset to the originial trim position as soon as you touch the joystick, e.g. during the take off rotation.
Not sure what you mean. I have Elevator Trim Up and Elevator Trim Down for manual trimming on my joystick hat switch, and the command mentioned above on a joystick side button to set take-off trim, similar to IRL. The latter simply saves me from having to set trim to take-off in the cockpit. Cheers.
Say in the C172. The elevator trim wheel has a marked position for take-off. Well, instead of having to use my mouse to turn the wheel to set that position, I simply push that button. Particularly handy for me because I often like to take-off in chase view - I get enough cockpit stuff IRL! Have you tried it? Cheers.
There’s no ‘fixed’ takeoff trim in larger aircraft like the King Air in your screenshot.
Takeoff trim depends mostly on weight, CG and flap position.
Each loading/configuration requires a different setting.
If you e.g. fly the King Air with the same loadout, CG and flap setting each time, you can experiment with changing the trim position until you find the perfect one which suits your needs.
Fair enough. I only fly a C172 IRL. I would not be surprised if MSFS, with all its bugs, does not yet allow what you say. Maybe file a zendesk bug. Cheers.
The point I’m trying to make is that if there’s a command for ‘takeoff trim’, it would reset the trim to the original position when you loaded the aircraft, hence you are back at the OPs problem.
One other thing I should note…when I take off with the C172, I put flaps in the 0 degree position. Not sure why MSFS defaults the C172 to starting with flaps at 15 degrees - but in a real 172 (at least any model I’ve flown), you only use flaps for soft field operations. Even short field takeoffs don’t use flaps.
Sometime I should try leaving the flaps improperly at 15 degrees…maybe then the TO trim actually produces a reasonable speed?
Hi @PZL104, you’re flying a newer model than I did! For the 172N, the POH definitely states no flaps for anything other than soft/rough fields (see attached pix). I didn’t realize other models didn’t follow the same.
To come back to the original point of this thread, highlighted in bold above, I completely agree that the standard “take-off trim” position (as labelled in the cockpit) on pretty much every aircraft appears to be incorrect, and results in the following behaviour:
a long ground run / high take-off speed, unless pull back sufficiently
a tendency for the aircraft to nose-dive back towards the ground once you get cleaned up and reach a reasonable climb speed, if you ease off the back pressure
As you said, it seems that the take-off trim position is more suited to cruise, and does not replicate a typical take-off trim position as found in every other flight sim I have used, ever. I know it will vary by weight & balance but it doesn’t seem to change whether light or heavy in my experience so far.
Perhaps this is an oversight such that the aircraft are pre-trimmed for a typical cruise configuration, to suit the majority of casual users who just want to quickly fly around and look at the sights, without even knowing what trim in an aircraft is. It wouldn’t surprise me. Much like the seat positions are too low in every aircraft (seems better in 1.9.3.0 though), the default trim might be wrong too.
One interesting point I noticed last night in the DA42:
When I started cold-and-dark, the trim was at the “take off position” and had a strong ‘nose down’ tendency after take off, as described above
When I started on the runway, engine running (after a CTD - forgot about the ■■■■ VFR map crash bug and hit ‘V’), the trim was set somewhat nose-up from the “take off position” and the aircraft took off more ‘naturally’ at a lower speed.
I’ll need to double-check to make sure I didn’t dream that, but if true then it suggests the trim is moved nose-up of “take off” as part of the automatic pre-flight sequence if you let it run.
Hi @Mustang242Sqn , thanks for bringing us back on topic
I haven’t been judging other planes compared to other flight simulators…but I’ve got a couple of hundred hours IRL in the C172, and I know in that airplane when trimmed in the take off position it’ll lift off the ground around 65 to 70 knots…never paid exact attention. And it “could” be that I was unconciously pulling back on the stick…but my gut feel is if I just let it float off the ground by itself it would have a steady climb at 65 or 70 knots.
Definitely not the “nose dive” which appears to be caused because, IMO, the Take Off trim position on the default model actually trims for 110 to 120 knots, instead of the 65 to 70 knots you “should” be climbing out at.
I’m going to wait until the next patch comes out next week to test again. I do want to test what would happen if I left the flaps in their first detent position (10 degrees or 15 degrees…not sure…what ever the first setting is). The C172 at least always has those down for takeoff, which is not correct for the version I flew (C172 N), but might (???) be correct for other models of the c172?
I have very little real life experience. After 5 minutes at the controls I have to hand over and prepare the sickbag, sadly. But I’d be surprised if all the other sims were incorrect and MSFS was correct. My experience in every other ‘realistic’ simulator is as you describe the real aircraft. A natural tendency to lift off by itself and climb…
I took off in the C152 last night at “take off trim”, flaps up. It lifted off between 90 and 100 knots, and in a completely flat attitude. It barely began climbing and wouldn’t have cleared the obstacles past the end of the fairly long runway if I had not pulled back. Definitely not what I would expect from a “take off trim” position! This was with the default 50% fuel and load out.
The other GA aircraft behave similarly in my general experience so far. If I apply some back pressure to lift off, reach climb speed and relax back pressure, they will pitch over into the negative range and start to return to the runway.
There seems to be a misconception about takeoff trim.
This doesn’t mean that you should expect the aircraft to take off on its own at the correct speed.
It’s just a trim range where you can expect to take off by applying a reasonable amount of force and the aircraft settle at a safe airspeed during the initial climb.
Since there are different weight, CG and flap positions and combinations of these for most aircraft, it’s impossible to have a one-size-fits-all trim.
You definitely don’t want your aircraft to lift off at a low speed on its own and pitch further up into a stall.
It’s obviously way safer if the trimmed airspeed is too high than too low.
You are not a passenger and sit there watching your aircraft pitching up or down on its own, you are actively and always controlling the pitch of your aircraft.
After establishing the initial climb attitude/speed you trim aways the force require to pull/push the yoke. That’s all. Applies to a 152 and to a 747.
In case of trainers like the 152 there are instructors who even let their students fly complete patterns with the trim fully up and fully down, so they get a feel about a mistrimmed 152 and how it handles.
