Aircraft veers to left then corkscrews into ground after take off

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Backtotheroots
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Re: Aircraft veers to left then corkscrews into ground after take off

Post by Backtotheroots »

I did fine before updating accusim to the May 2020 version.

Now I have this problem as well.

FSX STEAM.
With and without FSUIPC

50% fuel in wing tanks, 0% fuel in fuselage, 2 units trim up.

The aircraft lifts off by itself at around 100 kt by itself, rolls to the left and needs full right aileron to control until reaching 150kt or so. Then things improve.

Seems to me elevator trim should be set to 2 (or maybe even more) units trimmed down (instead of up).

TreeTops
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Joined: 07 Apr 2010, 06:13

Re: Aircraft veers to left then corkscrews into ground after take off

Post by TreeTops »

That would be because the aircraft is leaving the ground too early and cannot overcome the prop torque.
Try holding the nose down until you get 120 knots and keep the climb shallow until you get 150 knots.
go back and re-read Dudley's notes on taking off.
Cheers
Trev

Backtotheroots
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Re: Aircraft veers to left then corkscrews into ground after take off

Post by Backtotheroots »

Yes I agree....its lifting off too early...thats what I said.

The question is why is it doing that?

Did something change in the aircraft.cfg that causes this (maybe even desired) effect?
I previously had Accusim version 04/20/15. (yes long time since updating).
And now with the may update I have this „problem“.

I put a lot of time trying to figure this thing out.
I even tried uninstalling/ re-installing (sometimes I normally dont do because it almost never helps anyway...but just to show you how weird I find that I was able to do a normal take off before...and now I am not).

I could try reading up on T.O. technique, but that would mean it is me that is the problem.
I dont mind that....but it does not help to train me if someth8ng is wrong with my aircraft.

So, can you confirm you need to push to keep the airplane on the runway too......this is normal?

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MkIV Hvd
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Re: Aircraft veers to left then corkscrews into ground after take off

Post by MkIV Hvd »

Backtotheroots,

It's not the speed as much as it is the angle of attack. As you said it's taking off by itself at 100 knots, I am assuming that is from the three point position, in which case the lift component will exacerbate the torque effect to the point that you can't control it. I saw the post about 2° nose up (I don't know how that works for the poster below) and that will be the reason for the tail not wanting to come up more or less by itself around 80 knots. The same thing will happen during the takeoff roll, albeit earlier in the roll, if you try to hold the tail down with up elevator.

A normal takeoff for me is 2-3° nose down trim (depending on the fuel load in the fuselage tank), 55"/3000 rpm, stick neutral, the tail will start to come up when it's ready around 80-85 knots, hold the nose slightly above the horizon and start to ease it off the ground at 100 knots. You'll be airborne at approximately 105 knots at which point you'll want to accelerate to best climb speed of 150 knots, before increasing your rate of climb to enroute or circuit altitude.

EDIT:
Backtotheroots wrote: 11 Dec 2020, 10:13 So, can you confirm you need to push to keep the airplane on the runway too......this is normal?
No that's not normal...that is because of the trim setting as well.

Cheers,
Rob
Rob Wilkinson
A2A: Civilian Mustang, T-6, Bonanza, Comanche, Cub, C182, Spitfire, P-40, Cherokee, P-51 - VATSIM P4 and some other stuff...

Backtotheroots
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Re: Aircraft veers to left then corkscrews into ground after take off

Post by Backtotheroots »

Ok, well everything is bogged up now.

After reinstalling the Cherokee 180 and Conny I cant control the P51 yaw anymore at all.

Is there a way to really really uninstall all A2A aircraft and start from scratch?

TreeTops
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Re: Aircraft veers to left then corkscrews into ground after take off

Post by TreeTops »

Not able to control the yaw means too much power applied for the current speed of the aircraft on the runway.
Set up at a very long runway and slowly feed in the power. Initially to hold centreline, rudder will be the limiting factor, not power. Once the tail is up you can feed in the rest of the power quicker.
The symptoms you are listing here mean there is nothing wrong with the plane and everything to do with the pilot. Take your time with the takeoff roll, liftoff and initial climb out.
From the moment the wheels start rolling, for the next minute the mustang will be trying to kill you.
Cheers
Trev

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MkIV Hvd
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Re: Aircraft veers to left then corkscrews into ground after take off

Post by MkIV Hvd »

TreeTops wrote: 11 Dec 2020, 14:06 Not able to control the yaw means too much power applied for the current speed of the aircraft on the runway.
Set up at a very long runway and slowly feed in the power. Initially to hold centreline, rudder will be the limiting factor, not power. Once the tail is up you can feed in the rest of the power quicker.
The symptoms you are listing here mean there is nothing wrong with the plane and everything to do with the pilot. Take your time with the takeoff roll, liftoff and initial climb out.
From the moment the wheels start rolling, for the next minute the mustang will be trying to kill you.
It appears to me that now it is a sim issue, as I'm assuming by this whole thread that Backtotheroots understands the use of rudder to control yaw.

Your definition of not being able to control the yaw because of too much power for the current speed does not correlate at all with my short field takeoff procedure of 45-50 inches against the brakes and the advance to 61" at brake release. I have no issues keeping the airplane straight on takeoff.

As a matter of fact, advancing the power very slowly on takeoff can be worse than advancing it too quickly, because as the airplane accelerates it's quite easy to get to the point where you don't have enough airflow over the rudder to control the yaw with the tail down. Takeoffs should be planned to spend the least amount of time possible on the ground.

Cheers,
Rob
Rob Wilkinson
A2A: Civilian Mustang, T-6, Bonanza, Comanche, Cub, C182, Spitfire, P-40, Cherokee, P-51 - VATSIM P4 and some other stuff...

Backtotheroots
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Re: Aircraft veers to left then corkscrews into ground after take off

Post by Backtotheroots »

Yes it is is a sim issue now.
You are right, I do know how a rudder works :-)
I fly for a living so I can tell you that what I am seeing now is something entirely different than I had before.

Even with full left rudder and idle power, I can not compensate for the spinning to the left.

I just discovered a tread called something like „ I have lost tail wheel steering after a reinstall...AGAIN“

Seems to me thats what I have now.
I reinstalled and lost rudder control (the pedals move but there is no effect)

And I think it is because when you uninstall....not everything is wiped out.

I need to start from scratch....so please how do I completely remove and reinstall my A2A fleet.

thx.

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MkIV Hvd
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Re: Aircraft veers to left then corkscrews into ground after take off

Post by MkIV Hvd »

Unfortunately (for you :wink: ) I've never had to uninstall A2A aircraft, but I'm sure Nick or Lewis will be along shortly to help with that procedure.

It's in the back of my mind that I read about A2A making some upgrades to the torque and P-Factor specifications a while back that may be the cause of your original findings that something had changed after you updated your Mustang after having it for a long time. I believe they stated that the effects applied to FSX as well, but were magnified in P3D and I know when I moved from FSX to P3D it took me a bit to get comfortable with the airplane again.

You'll be back up and running with your Mustang soon I'm thinking... :mrgreen:

Cheers,
Rob
Rob Wilkinson
A2A: Civilian Mustang, T-6, Bonanza, Comanche, Cub, C182, Spitfire, P-40, Cherokee, P-51 - VATSIM P4 and some other stuff...

Backtotheroots
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Re: Aircraft veers to left then corkscrews into ground after take off

Post by Backtotheroots »

Thx Rob!

Since it cant get any worse I tried another uninstall/reinstall, but I reinstalled in a different order.

First installed the Cherokee 180 - all good as far as I can tell during a quick trial
Next installed P51 Civil, the P51 accusim - quick trial....Aaaaaand......all ok again.

Installed the Conny (comes with capt of the ship) - seems to work ok
P51 - still ok

updating accusim....Aaaaand....nope P51 broke again....no more tailwheel steering possible (except assym brakes).

Backtotheroots
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Re: Aircraft veers to left then corkscrews into ground after take off

Post by Backtotheroots »

Ok, I might have fixed it but I am not sure if it is a fix that breaks other things....

I have a backup folder of the complete STEAM folder from before messing with uninstalling/reinstalling etc.

First I tried replacing the aircraft.cfg file (in the Simobjects/Airplanes/WoP3_P51D_civ folder but that not help.

Then I simply replaced the whole WoP3_P51D_civ folder and that did work :-)
Tailwheel steering is back!

Now how do I know if my aircraft is COMPLETELY ok...that I have caused other problems with that folder copy/paste?

What makes me suspecious that something might still be off is that everything is too good now...lol
As in.....my original problem seems to have gone away now as well!
Is there way to tell what accusim verion my P51 is using (not what was installed....but what it is actaully using after the folder copy/paste)

I still prefer a complete and clean uninstall/reinstall over what I have just done by the way.

What do you say?

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MkIV Hvd
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Re: Aircraft veers to left then corkscrews into ground after take off

Post by MkIV Hvd »

Well Sir, you are now well beyond my area of expertise, but I'm sure someone from A2A will drop in soon with actual expertise... :wink:

I'm glad to hear you're up and flying again anyway!!

Cheers
Rob
Rob Wilkinson
A2A: Civilian Mustang, T-6, Bonanza, Comanche, Cub, C182, Spitfire, P-40, Cherokee, P-51 - VATSIM P4 and some other stuff...

Backtotheroots
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Joined: 17 May 2015, 10:35

Re: Aircraft veers to left then corkscrews into ground after take off

Post by Backtotheroots »

Haha, that makes two of us then :-)

Cheers,
also Rob

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Mazo
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Re: Aircraft veers to left then corkscrews into ground after take off

Post by Mazo »

To find the version:
1. Control Panel
2.Uninstall a program
Every A2A aircraft is listed with the version and date of installation.

Lyn
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Backtotheroots
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Re: Aircraft veers to left then corkscrews into ground after take off

Post by Backtotheroots »

Like I said...that will not work I think.

The control panel will probably display what was originally installed.
(I guess read from a registry entry righ?)

When I start swapping folders then that registry entry is not the same as what is in the folders.


Ps: still waiting for an uninstall procedure that removes everything.

thanks

edit: I do see others with similar questions. Is that UNWISE.EXE the way to uninstall everything?

edit: the uninstall feature for the P51 from the control panel also has a repair feature. But my Civil P51 is software from 2015 . The accusim update is from 2020. So what would happen if I click on the repair? Would that have restored nose Wheel steering in a proper way? Or would that have overwritten new files (2020) with old files (2015)?
Last edited by Backtotheroots on 12 Dec 2020, 06:43, edited 1 time in total.

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