Extreame Left Roll / Yaw On Takeoff.

[Nybble]

Hi all, I come with an issue that myself and a friend have been encountering, regarding the P51-D and takeoff.

 

To cut a long story short, we spent about 3 hours and 50 planes each in a multi-player server hosted by myself, trying to make a successful takeoff.

 

We know all the theory behind it, and can do it with ease in the training mission, however when attempted on the server, each takeoff resulted in failure.

 

The cause of the failure is that as soon as the plane gets off the ground, the left wing (Always left, regardless of wind) would dip down as hard as it good, and no amount of rudder and aileron trim + stick input can keep it level. This is compounded by the plane yawing to the left quite hard, making the aircraft spin out of control on 2 axis.

 

After our three hour session, we loaded up the training mission and had a go, and each of us had a successfully takeoff on our first attempt. Then, back into the server and we could not get one off the ground. 10 aircraft each later we decided it was time for a forum rant, so here it is.

 

Basically I was wondering if anyone else has encountered the issue, or if there is something we are both doing wrong.

 

A couple of notes:

1 - After unbinding all of the trim commands, I succeeded in taking off within the server on my first attempt. Any attempts after this however resulted in the same issue.

2 - When using the F2 camera, I have noticed that the left wheel (left side always goes down) clips though the runway a little, whereas the right side is perfectly stable.

 

I understand the game is in beta, but I can't see anyone else having this issue so we are wondering if it is pilot error.

 

Thanks for the read, I'll upload a track tomorrow if anyone is interested.

[cichlidfan]

Is it possible that you have take off assist or autorudder turned on when you are in SP training mission, but turned off in the MP mission?

[Slap_Chop]

I have had this exact issue but I actually thought it was something I was doing. But it was also happening to me when I created a Fast Mission where

I started cold from Ramp. I couldn't get off the ground without crashing no matter how hard I tried.

 

 

I did what you did as well and went back the original fast mission because I thought I was losing my mind. There I could take off with ease.

 

 

Yes it's a left wing roll over that is uncontrollable. Now that you've brought this up I will pay more attention and make sure I record tracks etc.

 

 

I'm not saying it isn't me but it catches me by surprise sometimes when I'm confident take off is mastered.

 

 

(oh and fast mission was flown in single player and all settings were realistic)

Edited September 30, 2012 by Slap_Chop

[dooom]

are you using a CH stick? Check your spring trim on the base of the tick if you are.

 

 

Are you sure you are allowing enough speed on take off??

[Echo38]

A full fuselage tank dramatically alters the P-51's center of gravity. Does the training mission start you with a full fuselage tank? Does the multiplayer mission?

[Slap_Chop]

A full fuselage tank dramatically alters the P-51's center of gravity. Does the training mission start you with a full fuselage tank? Does the multiplayer mission?

 

 

Hmmm you might be onto something .....

[WildBillKelsoe]

we need that mission/track badly so we can corroborate or negate yer claims.

what is the field you're taking off from?

[Nybble]

Thanks for all of the interest thus far!

 

cichlidfan: I had though of that, and I checked and rechecked but they are all disabled. Unless they are implicitly re-enabled for the training mission without our knowledge.

 

dooom: I am using a Thustmaster HOTAS Warthog, and my friend is using an X52-Pro. Also aircraft speed does not seem to be an issue. It gets to the stage where the plane is so fast it lifts itself however the roll scrapes the wing along the ground and thats it.

 

Echo38: The mission we were attempting it in each P51 had 50% fuel. In the training mission the aircraft has 68%. Also, game flight and avionics modes are enforced to OFF, and the g-effects forced to SIM.

 

WildBillKelsoe : I'll post a track of us taking off in a couple of hours, we'll do a few trials from a number of airbases. For the record the airbase in question was Gelendzhik, with no wind or weather effects.

 

On another note, my friend claims to have fixed the issue in my absence, and has been taking off with ease on another server. This leads me to believe that it may be an airbase issue, or a server related problem.

 

Thanks again, I'll post the track in a few hours!

[Nybble]

Update: I just did an hour long session with my friend, and after finishing we tried to save the track but neither of us could find where to save it! Any tips on saving tracks from multiplayer sessions?

[leafer]

DONE! :D

 

DCS: P-51D Mustang (Final), 1.2.1

 

http://www.digitalcombatsimulator.co...oducts&lang=en

 

This version marks the final version of this product and is no longer in beta.

 

• War Emergency Power (WEP) has been implemented.

• Tail wheel dynamics reworked for more realistic performance.

• Realistic cooling system added and integrated into the full engine thermodynamic model.

• Landing gear physics have been reworked to have realistic behavior and interaction with the fairing doors and down-lock latches.

• Fairing doors can now be damaged or ripped off at over-speed conditions.

• Engine wear or damage due to high manifold pressure at low RPM, overheating, and overuse of WEP has been implemented.

• Oil pressure is now viscosity dependent. Oil dilution is now possible and has direct impact on engine performance.

• The front dash gauge panel and the K-14 gunsight are now spring suspended.

• The K-14 gunsight has been reworked using new data from K-14 documents.

• The rudder anti-booster tab now works correctly.

• Control stick and rudder pedals movement are now limited due to hinge moments.

• Flap drag has been adjusted.

• Lamps brightness and electro-dynamic gauge readings are now voltage sensitive. You can best see this during engine start.

• The starter can now be burned out due to overheat if overused or overloaded.

• Guns jam due to over-G firing has been added.

• The radiator shutters' thermo-sensors can be damaged now.

• All aircraft failures are now reported correctly in debriefings.

• Sounds for the primer, pilot parachute opening and flapping during decent, and pilot landing have been added. The canopy sound has also been improved.

• Corrected tendency for left roll at takeoff.

• Adjusted Red Tail pilot art.

• Improved bailing out animation.

• Fixed landing light on with air start.

• Fixed cockpit tooltip for the gun switch.

• Corrected radio information entry in Mission Editor.

• Improved AI P-51D.

• Fixed SCR-522 resetting in some situations.

• Adjusted G impact on airframe.

• Improved pilot normal maps.

• Adjusted landing gear collision model.

• Corrected trim performance in multiplayer.

• Adjusted wingmen takeoff behavior.

• Improved prop RPM model.

• Sounds for control stick and rudder movement have been added.

[Exorcet]

Update: I just did an hour long session with my friend, and after finishing we tried to save the track but neither of us could find where to save it! Any tips on saving tracks from multiplayer sessions?

 

All MP tracks are auto saved in Temp folder.

 

As posted above, the issue is fixed in the patch released today.

[Nybble]

Woo awesome!

 

Thanks for that guys.

[Nybble]

I played quite a bit of 1.2.1 last night, and thought I would post in the event anyone else is encountering the problem.

 

There was definitely a problem with the left roll in 1.2.0, however it is still possible to encounter similar issues in 1.2.1 due to pilot error.

When heading down the runway for takeoff, even if you are perfectly down the center and at the correct speed you will encounter severe and uncontrollable roll if you pitch up to severely.

 

In 1.2.0 it was almost the opposite (in my experience), you had to pitch extremely hard to gain any control at all, however this still ended in a fireball most of the time. This conditioned me to pitch in the same manner in 1.2.1, which is a habit I had to break to reach a successful take-off.

 

I'm now taking off with a full weapons load-out and 75% fuel with no issues at all!

[VH-Rock]

When heading down the runway for takeoff, even if you are perfectly down the center and at the correct speed you will encounter severe and uncontrollable roll if you pitch up to severely.

 

Of course, you're in a slow aircraft, that's quite heavy, and you're trying to pull too much. It's no different than stalling in a dog fight if you let the speed get too low. Being perfectly centered doesn't make a difference at all.

[TimmyD]

If I put too much power on to take off she does tend to roll to the left a fair bit. Try using 42" Manifold pressure and a tiny bit of flap and she'll just fly off with you only having to make small corrective inputs. HTH ;)

[Nybble]

Just to be clear, I know the difference between the normal side roll which everyone encounters, and completely uncontrollable roll which I was getting.

 

My first posts were in reference to the uncontrollable roll (since been corrected), and my later post was in reference to how trying to counter that taught me bad habits in flying in the fixed environment.

[Echo38]

"Uncontrollable roll" sounds like you were stalling the airplane by lifting off at too high an AoA, using the ground effect which quickly become unavailable, resulting in a stall and wing drop.

[ttaylor0024]

Prop planes like the P-51 have 4 left turning tendencies, like what is being described here. The USA lost many planes due to this when they first came out, because the plane would dip left wing low due to these.

 

These tendencies are:

P-Factor- most pronounced at high angles of attack, the propeller is set at a slight angle to the fuselage, and when at a high angle of attack, such as takeoffs, the descending sided of the prop has a higher AOA than the ascending side, causing more lift, thus left turning tendency.

 

Torque- Prop turns to the right as viewed from the cockpit, counter-clockwise as viewed from the nose. Opposite reaction, left roll. (Thanks Echo38)

 

Spiraling Slip-stream- Prop wash spirals around the fuselage and hits the vertical stabilizer, but since there isn't a vertical stabilizer on the bottom of the aircraft too, the force is only in one direction, another left turning tendency.

 

Gyroscopic Precession- When a gyro is moved, force is 90* from rotation, then out. When your propeller is moving, it is essentially a gyro- it doesn't want to move. On takeoff, you pitch up, it doesn't like that. Last left turning tendency. It will initally yaw left, then the left wing will dip and roll. Thats why on crosswind takeoffs and landing you use opposite aileron. Example- left to right wind on final, you will crab into the wind to stay on centerline, then hit right rudder when close to the runway while using left aleron to keep the right wing from hitting the runway (and touching down your left wheel first).

 

Prop planes are much different than jets. I would give some info on tail-wheel attributes, but I don't have my tail-wheel endorsement...yet...

 

Sources: my pilot training (private pilot, almost complete with instrument)

Edited October 3, 2012 by ttaylor0024

[Echo38]

Ttaylor, a few amendments to your explanation: "Torque--prop turns clockwise, so the plane wants to roll the opposite way."

Also, replacing "turn" with "yaw," at least in the explanation of gyroscopic precession.

[ttaylor0024]

Ttaylor, a few amendments to your explanation: "Torque--prop turns clockwise, so the plane wants to roll the opposite way."

Also, replacing "turn" with "yaw," at least in the explanation of gyro precession.

 

And the yaw makes the plane roll also. It will initally yaw left, then the left wing will dip and roll. Thats why on crosswind takeoffs and landing you use opposite aileron. Example- left to right wind on final, you will crab into the wind to stay on centerline, then hit right rudder when close to the runway while using left aleron to keep the right wing from hitting the runway (and touching down your left wheel first).

Edited October 3, 2012 by ttaylor0024

[Echo38]

The propeller turns to the left as you view it inside the cockpit (right, or clockwise as you look at it form the nose), it makes the plane want to roll left as you are flying it.

 

Hmm--every action has an equal and opposite reaction. The propeller's clockwise revolution inspires counterclockwise revolution in the airframe.

 

And the yaw makes the plane roll also. It will initally yaw left, then the left wing will dip and roll.

 

However, the gyroscopic precession itself does not directly cause roll. The roll is caused by other factors which result from the gyro yaw.

Edited October 3, 2012 by Echo38

[ttaylor0024]

Hmm. Every action has an equal and opposite reaction. The propeller's clockwise revolution inspires counterclockwise revolution in the airframe.

 

Ah, I see where I went wrong, your right, The propeller turns to the right when inside- counter clockwise as viewed from outside. My bad, your right :) Still, the plane loves to torque roll.

[Echo38]

Still, the plane loves to torque roll.

 

I certainly won't argue with that! My first few takeoffs were ugly enough.

 

Best of luck with your taildragger endorsement, by the way. I am happy for you.

[ttaylor0024]

I certainly won't argue with that! My first few takeoffs were ugly enough.

 

Best of luck with your taildragger endorsement, by the way. I am happy for you.

 

Thank you sir. It was actually another member on here I talked to a couple years back that made me realize I want to be a pilot. I am going to school at K-State Salina to get 2 degrees- Professional pilot (all ratings through commercial, flight instructor, multi-engine, etc), and Unmanned aerial systems. I will try to bring back some knowledge on subjects like this :)

 

Anyway, back on topic

[mjolner]

Just flew the p51 with 1.2.1 last night. Did a few take off and landing runs to test the flight model changes. I was really suprised how minimal the roll tendency was even when pushing to the firewall and without the 5 degree rudder trim.

 

I went back into options to check my settings and made sure my flight model was set to simulation. Maybe I missed a new setting for auto rudder or something? I am at work so I cant verify anything but I hope I missed something in the options menu.

 

She behaves pretty tame compared to other obligatory P51 sims.

Edited October 14, 2012 by mjolner