severe turning just after taking off..

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Aceman
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Re: severe turning just after taking off..

Post by Aceman »

Hey guys... I just made a short video on what is happening.. As you can see in the video, the plane turns too the left..

https://youtu.be/td2J8Q38wRo

Jason

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mallcott
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Re: severe turning just after taking off..

Post by mallcott »

Looks like rubbish technique more than anything.

Way too fast raising the power
Nowhere near enough foot movement on the rudder pedals
No fore/aft stick movement to unlock/lock the tailwheel
Don't know why your IAS indicator isn't moving, but you need to wait until you have rudder authority before you add power to t/o, and make sure you've lifted the tail to unblank the rudder
In this case the aircraft starts left, your rudder response is too little, too late and then despite the absence of rudder authority you added power to over 40"

Hopefully this helps hone in on what you're doing wrong.

TreeTops
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Re: severe turning just after taking off..

Post by TreeTops »

Correct. It can be seen in the last second on the video when substantially more power is added that there is a noticeably greater left turn caused by increased torque.
Find yourself a really long airstrip and take your time increasing power. I think you will find if you have patience in building up speed to 60-70 knots, the rest will come easier.
Cheers
Trev

Aceman
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Re: severe turning just after taking off..

Post by Aceman »

I have been taking off and landing this bird for 100's of times and never run into this issue. I cranked the rudder to 8.0 and did a very slow start down the runaway. It STILL has a problem with turning. It's not a power issue. Like I said.. I did a slow running up not even half throttle and it turns. Very frustrating.. Full tank on wings and in body. This problem did not show up until I updated.. I am not doing anything wrong.

TreeTops
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Re: severe turning just after taking off..

Post by TreeTops »

Did you mean set the rudder trim to 8? This will have no effect until you leave the ground.
What happens if you leave it at 20" MP and let it roll down the runway? Does it stay straight then balancing on the rudder?
Half throttle is not stating power accurately. Always talk in Inches MP with such a powerful engine.
Abrupt change in MP from 15 to 30 will kick you left. Smoothly run up to 20" MP over many seconds and leave it there to see what happens.
Also, remove the fuel from the fuselage tank. This will only add to your problems.
I agree with Malcott below, if you think you are doing it right you are mistaken judging on the video you posted. Hundreds of poor technique take offs prior to the more accurate update dynamics does not mean it's broken. It's pilot technique.
Forget about taking off. Just achieve a successful tail up and trundling down the runway to get past this psychological barrier you have built for yourself.
Also you want to be quicker on the right rudder pedal. The nose has swung through to the left before you have right rudder applied. Momentum is already working against you holding it straight. As soon as the plane stops kicking right you need to be looking at right rudder to stop the inevitable left turn.
Last edited by TreeTops on 30 Jan 2017, 17:31, edited 3 times in total.
Cheers
Trev

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mallcott
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Re: severe turning just after taking off..

Post by mallcott »

Aceman wrote:I have been taking off and landing this bird for 100's of times and never run into this issue. I cranked the rudder to 8.0 and did a very slow start down the runaway. It STILL has a problem with turning. It's not a power issue. Like I said.. I did a slow running up not even half throttle and it turns. Very frustrating.. Full tank on wings and in body. This problem did not show up until I updated.. I am not doing anything wrong.
The video suggests otherwise. Advice is freely offered. If it is not taken then really there is little point in continuing. You don't even address the individual points.

What is this `cranked the rudder to 8.0`? Are you truly messing with the aircraft .cfg file on this bird? I told you, it's your technique - or you haven't calibrated the rudder axis correctly.

Good luck solving your problem. I'm out.

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Jacques
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Re: severe turning just after taking off..

Post by Jacques »

I thnk "dancing" on the pedals is a good term to remember, both left and right, just to add a bit to what Treetops is saying.

AviationAtWar
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Re: severe turning just after taking off..

Post by AviationAtWar »

You really need to start with the stick all the way back. Add power slowly and stay on the rudder. Only when stable can you continue to add more power and start to ease off the elevator. In the video you added a bunch of power just before the video ended but the airplane wasn't under control when you did. If you're not under control to start with then adding a bunch of power is definitely going to cause problems. Unless you're heavily loaded you don't need more than 40-45" for takeoff and you can use much of the runway length to add the power in.

I have a couple Mustang videos but none showing stick and rudder inputs. I'll try to get one up tonight.

AviationAtWar
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Re: severe turning just after taking off..

Post by AviationAtWar »

I have around 300 hours in the Mustang now and haven't had any issues. I've seen these 'Mustang pulls left' threads keep coming up and I've always wondered if it was all technique or if there was actually a problem. Ground handling on all the warbirds was changed last year with the T-6 release and I really don't know if there is actually some kind of installation/update issue or if it's technique. Maybe I've been one of the fortunate ones without issues, I don't know.

In the case of the video posted above; Aceman, respectfully, there are several mistakes going on there and I think you'll be fine with some practice. As mentioned above, find a long and wide runway somewhere and practice for a while. I made this video tonight, see if this helps.

[youtube]http://www.youtube.com/watch?v=39TozyVFWuU[/youtube]

Aceman
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Re: severe turning just after taking off..

Post by Aceman »

Hey thanks Aviationatwar! That was very nice if you to show me how to do the take off! I will pull out my 51 a go and try it. I will for sure make sure the stick is back and of course a nice smooth throttle input. I will let you know! It's a big help to actually see what is going on. :P

Cheers.. Jason

TreeTops
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Re: severe turning just after taking off..

Post by TreeTops »

Please report back on your experience.
Fully experiencing the P-51 and all its demands sure is a challenge. Just a little bit of a step up from the default C172. :)
Cheers
Trev

wrkempson
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Re: severe turning just after taking off..

Post by wrkempson »

What a great video by Aviation. If I am seeing things correctly, it looks like he anticipates that first right hand drift, but then quickly starts to apply right rudder before the leftward pull. This seems to be the key. We know there will be a left hand pull, so anticipate it with the rudder before it kicks in.

Am I right that Aceman was chasing the turn, applying rudder only after the leftward pull begins? It seems to me this results in being behind instead of in front of the turn.

Anyway, great videos on both counts, and both very informative for me. I have 200 hours in this aircraft simulation and was gratified to see my takeoffs looking a lot like Aviation's.

A nice wide and long runway for practice is Edwards AFB.

Wayne

Aceman
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Re: severe turning just after taking off..

Post by Aceman »

I tried it again this morning.. I watched the video completely. Had the rudder set for 6.0 deg to the right. Had the stick all the way back on the takeoff. It still turns to the left. I mean I have it barely cracked open and once I hit 25 mph half way down the runaway, it started to turn left again... hummm.... :roll:

Maybe just uninstall the plane completely. It funny, it works just fine before the update 1/17/17.

that my report..

I am sorry I am being a pain.. :lol:

AviationAtWar
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Re: severe turning just after taking off..

Post by AviationAtWar »

Try uninstalling it I guess, delete the P-51 update folder, reinstall it and see what happens. If you still have issues upload another video if you can and we'll take a look at it.

Aceman
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Joined: 27 Jan 2011, 13:59

Re: severe turning just after taking off..

Post by Aceman »

Hey Guys... I uninstalled the 51 and removed all of the files associated with it. Reinstalled and takeoffs are working just fine! Beautiful takeoffs. I am now hold the stick back and making my run down the runaway now. Much more stable for sure! I don't know what happened but it's flying great now!

Jason

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