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Cessena 172 leaving ground to early with no elevator input

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Cessena 172 leaving ground to early with no elevator input

Postby johndc » Sat Jan 12, 2019 4:44 pm

Brand new to FG. Going through tutorials. In takeoff tutorial, plane leaves runway too soon before desired takeoff speed, with no elevator input whatsoever. Makes control of the aircraft almost impossible. I have a Saitek st290 pro controller. Any ideas? I am using keyboard for rudder control to control steering while on ground.
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Re: Cessena 172 leaving ground to early with no elevator inp

Postby legoboyvdlp » Sat Jan 12, 2019 4:49 pm

Hi,
What speed is it leaving the ground at? The normal takeoff speed is around sixty knots.

Are you using live weather? If so, maybe you have a strong headwind as well, which could cause you to takeoff at a slower speed. However, your airspeed indicator will still show 60 knots as it adds the wind speed to the 'true' speed.
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Re: Cessena 172 leaving ground to early with no elevator inp

Postby Knüppelrührer » Sat Jan 12, 2019 4:52 pm

Small checklist:

- is your joystick really centred?
- what is the trim setting? (position of the mark of the trim wheel)
- maybe something loaded in the back of the plane? Might be worth checking in the fuel and payload menue.

At what speed is the aircraft leaving the ground? Normally it should be rotation at 50kts and then liftoff at 56kts or so.

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Re: Cessena 172 leaving ground to early with no elevator inp

Postby johndc » Sat Jan 12, 2019 7:24 pm

leaving ground by itself at 50 knots. Joystick is dead on. I think rudder position may be my problem. Is there a way to view rudder position input while I am flying? I want rudder to be at 0 when it leaves ground. But this still does not address the fact that it is leaving with no elevator input
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Re: Cessena 172 leaving ground to early with no elevator inp

Postby Knüppelrührer » Sat Jan 12, 2019 7:29 pm

Rudder shouldn't be a problem as it does only yaw (plus a bit of roll).

If you use the HUD (press h) you can see your rudder inputs.

maybe trim not on takeoff position?
When you hover with the mouse over the wheel, it gives the numerical value. For example 0.15 is fine.

Flaps are up?
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Re: Cessena 172 leaving ground to early with no elevator inp

Postby Knüppelrührer » Sat Jan 12, 2019 8:22 pm

After some testing:
With the elevator trim at exactly the takeoff mark, the aircraft is leaving the ground without input.
You can fly like that without any problems.

By default the trim is a bit more forward, which means you have to pull a small bit and then have a good trim for the initial climb method.

Looks realistic to me. Hence: no worries, mate!
Last edited by Knüppelrührer on Sat Jan 12, 2019 9:43 pm, edited 1 time in total.
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Re: Cessena 172 leaving ground to early with no elevator inp

Postby legoboyvdlp » Sat Jan 12, 2019 9:37 pm

johndc wrote in Sat Jan 12, 2019 7:24 pm:leaving ground by itself at 50 knots. Joystick is dead on. I think rudder position may be my problem. Is there a way to view rudder position input while I am flying? I want rudder to be at 0 when it leaves ground. But this still does not address the fact that it is leaving with no elevator input


As you speed up you will gain lift. I don't think this is necessarily a problem - it definitely depends on your trim position.

Rudder will have no impact whatsoever on pitch
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Re: Cessena 172 leaving ground to early with no elevator inp

Postby johndc » Sun Jan 13, 2019 3:36 am

I cannot control the airplane with my controls. I am not a pilot but I do have experience with MS flight simulator and I never experienced this problem with their C172 sim. MS seems more realistic in the aspect of controlling by elevator and aileron. As far as I am concerned the C172 realism should be a top priority in this program. Just my humble opinion. I am finished with this tutorial. It did not help whatsoever.
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Re: Cessena 172 leaving ground to early with no elevator inp

Postby sidi762 » Sun Jan 13, 2019 3:47 am

johndc wrote in Sun Jan 13, 2019 3:36 am:I cannot control the airplane with my controls. I am not a pilot but I do have experience with MS flight simulator and I never experienced this problem with their C172 sim. MS seems more realistic in the aspect of controlling by elevator and aileron. As far as I am concerned the C172 realism should be a top priority in this program. Just my humble opinion. I am finished with this tutorial. It did not help whatsoever.

Hi Johndc,

Welcome to FlightGear!

Does not mean to offend, but if you're not using a2a c172 then the c172 in MSFS is a piece of junk. The reason you feel this c172p hard to fly somehow is that in real life your yoke is directly connected to the control surfaces, so you will feel the forces on it to prevent your movement on your yoke. In FlightGear you are using either mouse or yoke that doesn't reflect that force on your hand, so you can easily over control, causing unusual or dangerous movement of the plane.

Best Regards,
Sidi
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Re: Cessena 172 leaving ground to early with no elevator inp

Postby Octal450 » Sun Jan 13, 2019 3:58 am

That is incorrect behavior. IRL, trim is actually slightly downward, or neutral for takeoff, and doesn't need to be adjusted much after takeoff (of course a little, but not as much as you describe). That sounds like the pitch axis of the Aero needs work.

Trim should not need to be moved that far back to remain stable during flight.

Kind Regards,
Josh
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Re: Cessena 172 leaving ground to early with no elevator inp

Postby sidi762 » Sun Jan 13, 2019 4:16 am

it0uchpods wrote in Sun Jan 13, 2019 3:58 am:That is incorrect behavior. IRL, trim is actually slightly downward, or neutral for takeoff, and doesn't need to be adjusted much after takeoff (of course a little, but not as much as you describe). That sounds like the pitch axis of the Aero needs work.

Trim should not need to be moved that far back to remain stable during flight.

Kind Regards,
Josh

Hi Josh,

Just tested with C172p of 2018.3.1. With little wind, no yoke input and neutral trim, it doesn't lift off until 75 kts.

I'm not sure about it since I have no RL experience. Does it feel right to you?

Best regards,
Sidi

EDIT: Sorry forgot to mention, it's with default load.
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Re: Cessena 172 leaving ground to early with no elevator inp

Postby Octal450 » Sun Jan 13, 2019 5:47 am

Well, I've never stayed on the ground to 75kts, so I don't entirely know. But that does probably sound more right. In the air, what happens, do you need to "trim excessively" as said above?

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Josh
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Re: Cessena 172 leaving ground to early with no elevator inp

Postby sidi762 » Sun Jan 13, 2019 11:45 am

it0uchpods wrote in Sun Jan 13, 2019 5:47 am:Well, I've never stayed on the ground to 75kts, so I don't entirely know. But that does probably sound more right. In the air, what happens, do you need to "trim excessively" as said above?
Kind Regards,
Josh


No, I usually press the key for just two to four times and it flies quite happily.

Best regards,
Sidi
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Re: Cessena 172 leaving ground to early with no elevator inp

Postby sim » Sat Jan 19, 2019 11:24 am

Conflicting reports! One saying c172 takes off at 50 knots without needing elevator and Another saying c172 needs to reach 75 knots before lift off. Pilot 1 should be happy, Pilot 2 either your trimmed nose down or you've too much ballast on board! :roll:

Heck! Try the c150 that's much more fun!
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