Pitch and yaw stabilty in Approach config.

[IvanK]

As you decelerate towards 150MPH with Gear and 2 stages of flap there is a distinct reduction in both Pitch and Yaw stability. It looks very similar to a mini dutch roll phugoid.

[july865]

Manual pg. 100, good reading material

[IvanK]

Yep read that. Thats not what I am referring to. Its a general change in stabilty not trim with configuration change I am talking about.

[Vitesse2l]

Don't have the manual to hand right now, but I'm wondering about this too.

 

What I'm seeing is an oscillation in yaw and pitch when in landing configuration. Speed is generally between 110 - 150 and trim is correct, I think, with elevator and aileron neutral and rudder centering the ball. Full flaps.

 

Probably me, but from the reading I've done there's no mention of this behaviour.

 

Cheers!

[159th_Viper]

Track please :)

[Vitesse2l]

Well, just tried a couple of approaches being extra careful about getting configured and taking care not to be ham fisted with the joystick.

 

Problem gone away.

 

Move along, nothing to see here...

[71st_Mastiff]

no no I'm having the same issue, the figure 8 oscillation when configured for landing.

I'm wondering now if it's the wieght of the A/C?

 

I think I had invisable rockets and bombs?

Are they there, is the A/C still wieghted if I forgot about them?

[brydling]

I have witnessed this a lot of times too.

[IvanK]

I spoke to a personal friend today who regularly flies a restored Mustang and described this behaviour to him. In his opinion he couldn't recall any such change in stability in this phase of flight.

 

A good way to visualise this "nose wandering" is to select GYRO + Fixed with the reticle masked. As the nose wanders it is then clearly visible as the Gyro reticle oscillates around the +. The onset of this phenomena seems to be very IAS specific at around 140MPH.

 

Is there a way to start and stop a track in flight or do you have save the entire flight after the event ?

[JimMack]

I spoke to a personal friend today who regularly flies a restored Mustang and described this behaviour to him. In his opinion he couldn't recall any such change in stability in this phase of flight.

 

A good way to visualise this "nose wandering" is to select GYRO + Fixed with the reticle masked. As the nose wanders it is then clearly visible as the Gyro reticle oscillates around the +. The onset of this phenomena seems to be very IAS specific at around 140MPH.

 

Is there a way to start and stop a track in flight or do you have save the entire flight after the event ?

 

Maybe use TacView to get exact parameters?

[EtherealN]

Entire track is needed, but it needent be long - you could just set up your plane next to a field in the mission editor and do a cirquit where the behaviour shows itself.

[IvanK]

Ok will do

[IvanK]

Quick Youtube vid to show the issue, Nose wandering can be seen from about 36seconds in. Track to follow

 

 

Discovered another bug. K14 Gyro reticle doesn't work in any user made missions that use a Runway Takeoff as a start waypoint. Gyro reticle is visible bit caged to the centre point ... evident in video above. Will report in separate bug thread.

[aaron886]

I saw something similar once, but not since. (I've probably only made 10-15 full patterns in the thing FWIW.) I'm not sure if it's what your describing; I noticed it as extreme pitch and yaw sensitivity in a fully dirty turn at ~120 mph.

[IvanK]

Thats exactly the issue aaron886

[aaron886]

Wondered if it might be damage, I was putting a lot of G on the thing beforehand.

[IvanK]

Another vid. In this one LG down 2 stages of flap. Nose wander is induced by Power changes, all be it fairly quick ones to emphasise the issue. Trk supplied is similar setup with much smaller power changes typical to those used on final approach to peg the speed.

 

nosewander.trk

[71st_Mastiff]

exactly the same issue I get.

 

Also when trying to fight the Invincible AI. I have tried to set my curve to as high as 30 and still I get snapped rolled, or stalled. The AI seems to fly a very clean plane with no problem and more high G turns than me and not flip the plane.

 

:thumbup:

Edited May 4, 2012 by Mastiff

[Vibora]

exactly the same issue I get.

 

Also when trying to fight the Invincible AI. I have tried to set my curve to as high as 30 and still I get snapped rolled, or stalled. The AI seems to fly a very clean plane with no problem and more high G turns than me and not flip the plane.

 

:thumbup:

The AI uses simplified flight model (SFM), so it doesn't flick roll.

Aircraft and stick shaking due to stall is not implemented yet.

Ammo weight is not taken into account for FM, so making a mission with a P-51 Human vs P-51 AI you should set fuel loading for HUMAN less the ammount of ammo weight. For example if ammo weight is G_ammo then:

 

GW_human = GW_AI - G_ammo.

 

So, you could use for example, 30% fuel and 69% fuel for the AI.

 

AI can not use 67" MP temporarily so that both sides are equal.

[HiJack]

So basicly you can slow down the AI with 100% fuel to get an easy target with your own 20% fuel? And set unlimited fuel :D

[Weta43]

From http://www.wwiiaircraftperformance.org/f4u/p-51b-f4u-1-navycomp.pdf

[Yo-Yo]

Another vid. In this one LG down 2 stages of flap. Nose wander is induced by Power changes, all be it fairly quick ones to emphasise the issue. Trk supplied is similar setup with much smaller power changes typical to those used on final approach to peg the speed.

 

 

.

[IvanK]

From http://www.wwiiaircraftperformance.org/f4u/p-51b-f4u-1-navycomp.pdf

 

Yes ok but how does what we are seeing in game compare to first hand pilot accounts today ? Might be worthwhile putting to your P51 pilot helpers/testers.

[Weta43]

It has been.

I know the P-51 is lionised as the greatest fighter of WWII, but it had its defects, and low-speed handling was up there among them:

 

"But everything was not perfect. As previously mentioned, the margin between stall speed and maximum engagement speed (on the wire) was small, too small for safety. Rudder control at low speeds and high angles of attack was inadequate. In addition, landing attitude had to be carefully controlled to avoid damaging the airframe upon landing.

 

One of the handling quirks of the Mustang was also potentially dangerous. During a missed approach or a wave-off, power has to be re-applied gently. If not, the aircraft could roll rapidly, or even snap-roll. At such low speed and altitude, the result could only be fatal."

 

The navy considered the P-51 usuitable for carrier use because (besides the P4U-1 having better speed, climb, manouverability and firepower)if you weren't careful, it did just what you're showing in your video when approaching slow.

If you're careful, that behaviour can be controlled.

 

Well, just tried a couple of approaches being extra careful about getting configured and taking care not to be ham fisted with the joystick.

 

Problem gone away.

 

Move along, nothing to see here...

Edited May 5, 2012 by Weta43

[Slayer]

Not sure if the fuel weight is accounted for yet but I notice a lot of people hardly ever switch tanks. result...imbalance wonky aircraft