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Cessna always turns left

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Cessna always turns left

Postby Ultra109 » Sat May 18, 2019 1:37 pm

When I'm on the runway, the Cessna turns left regardless of the rudder being in the centre, and when I'm in the air, the Cessna still turns left and rolls left as well without me doing anything. Please tell me there is some fix for this and isn't some feature that can't be changed, because otherwise I can't fly the plane at all and it's just getting stupid now.
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Re: Cessna always turns left

Postby Octal450 » Sat May 18, 2019 2:00 pm

It is supposed to do that, p-factor: https://en.wikipedia.org/wiki/P-factor

But I will point out that it is too strong in the FG 172.

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Re: Cessna always turns left

Postby wkitty42 » Sat May 18, 2019 2:59 pm

the P-factor effect should be weaker in the next release of the c172p...
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: Cessna always turns left

Postby wlbragg » Sat May 18, 2019 3:03 pm

Please tell me there is some fix for this and isn't some feature that can't be changed, because otherwise I can't fly the plane at all

Even if by design, you should be able to fly the aircraft. Many other people do including myself. I use a mouse and keyboard. What type of control hardware are you using?
How bad does this roll happen, bad enough you can't counter it with rudder?
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Re: Cessna always turns left

Postby Thorsten » Sun May 19, 2019 5:34 am

Please tell me there is some fix for this and isn't some feature that can't be changed, because otherwise I can't fly the plane at all and it's just getting stupid now.


It's what real single prop planes do, so you better get used to it... Try a jet or a twin prop plane - they don't do that.
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Re: Cessna always turns left

Postby Alant » Sun May 19, 2019 8:46 am

Thorsten wrote in Sun May 19, 2019 5:34 am:
It's what real single prop planes do, so you better get used to it... Try a jet or a twin prop plane - they don't do that.


Some (mostly powerful WWII fighter planes) do it more than others.
As has already been said in this thread FG's C172 simulation may be over enthusiastic and the effect has been reduced in the up and coming revision.

My own limited experience of the real aircraft is that the effect is noticeable on take off, but not in cruise.

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Re: Cessna always turns left

Postby roberto.jobet » Tue May 28, 2019 8:55 pm

Hi,
Same problem here (...)

Using FG ver. 2018.3.2 on Windows 10 (64bit) with mouse and keyboard.

Any tip?

Thanks.

Regards,
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Re: Cessna always turns left

Postby wkitty42 » Wed May 29, 2019 1:40 am

if you don't know already, look up "P-factor" and you'll understand why this happens in single engine craft...

yes, in the c172p, the effect is a little too strong but as mentioned above, it has been tweaked in the next release of the craft... the only real option is to wait for the next release to hit the streets and then update...

if you want to run on the bleeding edge, you could pull a snapshot of the craft from the development repository, place it in your custom craft directory, and use that one instead of the one delivered with the install...
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: Cessna always turns left

Postby Johan G » Fri May 31, 2019 6:59 pm

Some posts were split off to the new topic Possible JSBSim issue with tail-dragger aircraft.
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Re: Cessna always turns left

Postby Fullaly » Fri Jun 26, 2020 10:46 pm

same happen to me. however, it doesnt seem reallistc because even if I do max to he right still flying to the left. something is extremly weird about that
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Re: Cessna always turns left

Postby dilbert » Sun Jun 28, 2020 11:30 am

Using Win10 and 2018.3.5, Just flew the 172. The slipstream swirl from the prop required a modest amount of right rudder at takeoff and full power, which became neutral at 80 K and slightly left at 120 k; which felt correct to me, having flown a real 172-provided its rudder wasn't properly trimmed. I don't think the effect should be reduced. What I do think, is that the FG version needs a rudder trim facility. The real bird I flew 30 years, or so , ago had a saw tooth aluminum strip below the panel, which served as a detente for the rudder trim lever. X notches right for TO, x notches left for cruise, etc. Assume later models had a similar arrangement. Using keyboard versus stick seems part of the problem; as a twist stick enables you to maintain constant, but not excessive, rudder pressure, which is not doable with keyboard. In either case, addition of rudder trim would fix the problem.

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Re: Cessna always turns left

Postby legoboyvdlp » Sun Jun 28, 2020 2:03 pm

There should be a rudder trim option - did you check the config options?
It's on the lower panel, a lever near the aileron and elevator trim.
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Re: Cessna always turns left

Postby dilbert » Sun Jun 28, 2020 8:40 pm

Thanks

Ah yes, if you go to 172 p options in the top menu, there's a show rudder trim option , which if checked causes a rudder trim wheel to appear, as Legoboyvldip has stated.

Ultra109, if you check the box, you should be able to trim the rudder and solve your problem.

Given the number of complaints in this regard, why isn't the wheel displayed in default mode? :?
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Re: Cessna always turns left

Postby wkitty42 » Sun Jun 28, 2020 11:58 pm

dilbert wrote in Sun Jun 28, 2020 8:40 pm:Given the number of complaints in this regard, why isn't the wheel displayed in default mode? :?

because it is not authentic for the year craft the c172p is in the sim... this is an 81 or 82 model and they don't have anything inside the cabin for this... only one outside on the rudder which you bend to manually adjust (if needed) before flying...
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: Cessna always turns left

Postby dilbert » Mon Jun 29, 2020 8:55 am

Good grief. According to my logbook, those I flew between 9/6/84 and 3/24/85 were most likely later models. Certificate numbers were 4857G and 5323e. :o

Nope: according to FAA cancellation records, 4857G was a 1979 model.

Excerpt from 2006 training manual:

"With a trim lever, trimming is accomplished by lifting the trim lever up to clear a
detent, then moving it either left or right to desired trim position (as shown in
the picture below). Moving the trim to the right will trim nose-right, conversely,
moving the lever to the left will trim nose-left.
The rudder trim control is connected via a bell crank to a bungee, which is
directly connected to the rudder pedal control bar and thus to the rudder itself.
by D. Bruckert & O. Roud © 2006"

Some year models also had the trim wheel, as included in the FG 172p>options menu.

http://www.cessna172club.com/forum/ubbt ... ber=225029


Thanks Wkitty42, and kind Regards.
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