missing info Tailwheel Flight Model

[maajr57]

My experience is with the P-51D but probably applies to all the tailwheels. I would like to see DCS improve the flight model particularly for when the plane is on the runway both taking off and landing. The plane does wild yaws that are very unrealistic. I understand about torque and ground loops and such but planes don't travel down the runway sideways in real life. The amount that the plane can yaw before it stalls or has a wing strike needs to be more limited. 

[grafspee]

This one went sideways a lot.

Any way i find P-51 the most stable plane on the ground, you have to do something wrong if you are drifting it sides way during landing or take off.

Edited October 23, 2022 by grafspee

[Ala13_ManOWar]

Yep, I hardly recall going "sideways" ever, somewhat unstable when mistreated and as per seen in any tail dragger on YT for instance (I have flown TDs IRL a few times, but never had to opportunity to skid it sideways) and specially… well in 2014 when it first came out and we knew nothing about it in a simulation environment, yes, it happened, but nothing wild or out of the norm in a TD. If something, I think the FM is milder, all of them are, after a while from release time and P-51 is no different in that. But too much? If you ask me I think the Pony is too forgiving compared to what it was, which means nailed behaviour IRL just harder to control on a PC with no feeling at all so they ease it a bit.

You're right, planes don't travel down the runway sideways, the pilot at the controls put it that way. But a bit of practice makes magic. And don't try to compare it to anything you'd used before in PC, DCS in literally a unique software for the purpose, so it's either you know RL behaviour or nothing to compare.

Well, I stand myself corrected… or not, it's still the pilot .
 

 

[AJaromir]

From my experience the take-off with P-51D in DCS:World might be unstable at some conditions.

First of them is overweight. Make sure your aircraft load is in weight limits.

Second - make sure you have set rudder trim 5° right.

Third - make sure you pull your stick a bit. There is mechanism which locks the tailwheel when the stick is pulled. When the stick is pushed, the tailwheel is unlocked to be able to do sharp turns.

Remember, the best take off and landing is perfomed from/on 3-points. Taking off from two points need extra rudder pedal kick when lifting tail - to compensate gyroscopic precession which is created by change of attitude. 

Time 20:20

 

Edit: reminder - All of those factors (specially the slip-stream) are most strong when the engine power is at maximum and aircraft speed at minimum. One of those reasons is almost no rudder authority caused by no airflow. All flight control surfaces need airflow to be effective.

Edited October 26, 2022 by AJaromir

[AJaromir]

Here is the video with take-off and landing which I've made today in 2.8.0 You can see in input graph (the red square in bottom left cornet) that my rudder input is very stable. P-51D gains rudder authority very fast. Also you can see the take off and landing is very stable.

 

[NineLine]

On 10/23/2022 at 10:07 AM, maajr57 said:

My experience is with the P-51D but probably applies to all the tailwheels. I would like to see DCS improve the flight model particularly for when the plane is on the runway both taking off and landing. The plane does wild yaws that are very unrealistic. I understand about torque and ground loops and such but planes don't travel down the runway sideways in real life. The amount that the plane can yaw before it stalls or has a wing strike needs to be more limited. 

I need a track of your issue so I can review, thanks.

[maajr57]

Hello all and thanks for the replies. Please go to the Callenge Campaign Mission 3 and demonstrate the technique for a crosswind takeoff. I think u will all get a better understanding of the flight model issues. I set up the same crosswind with the P-51 in X-Plane and had no issues.

[grafspee]

12 hours ago, maajr57 said:

Hello all and thanks for the replies. Please go to the Callenge Campaign Mission 3 and demonstrate the technique for a crosswind takeoff. I think u will all get a better understanding of the flight model issues. I set up the same crosswind with the P-51 in X-Plane and had no issues.

I don't have this Campaign. Can you tell me what weather conditions are on this mission i will try replicate it in mission editor so i will get better understanding of this.

[AJaromir]

On 11/7/2022 at 10:20 AM, grafspee said:

I don't have this Campaign. Can you tell me what weather conditions are on this mission i will try replicate it in mission editor so i will get better understanding of this.

It is default campaign included in base P-51D. I will try that.

[grafspee]

Oh ok then i will try it too.

 

[=475FG= Dawger]

On 10/23/2022 at 12:07 PM, maajr57 said:

My experience is with the P-51D but probably applies to all the tailwheels. I would like to see DCS improve the flight model particularly for when the plane is on the runway both taking off and landing. The plane does wild yaws that are very unrealistic. I understand about torque and ground loops and such but planes don't travel down the runway sideways in real life. The amount that the plane can yaw before it stalls or has a wing strike needs to be more limited. 

I have a bit over 5000 hours in taildraggers, from very lightweight experimental aerobatic aircraft up to the B-17. "Going sideways" is an ever present danger in any taildragger. They are a very different animal when compared to tricycle gear aircraft.

If anything, DCS tail draggers are very forgiving and easier, which is good because in a real aircraft you feel the swing before you see it and can correct earlier. Properly simulating a tail dragger ground handling is impossible without serious motion actuation and even then it would be pretty kludgy.

[grafspee]

@maajr57

I found a mission, i must say 20kts cross wind is pretty absurd for P-51 when planes like 737 can handle  30 kts cross winds, depends on runway conditions.

How can any one expect to be easy to do that kind of take off, i doubt that any  P-51 pilot would do that now.

I managed after couple tries does not look perfect but i managed.

 

Edited November 9, 2022 by grafspee

[AJaromir]

Crosswind take-offs and landings are always difficult. You must keep yourself lined with runway. You have to use ailerons to keep aircraft's nose "straight" For example, when there is strong crosswind from left side, you have to roll left. In the result the right wheel will be in air sooner than left wheel. Same technique is used for landing. You can choose the "beginner" style which is: "Line up nose with airfield on final approach and compensate turning by roll" The "pro" style is: "press rudder pedal to line up with runway just right before touchdown - about second or two before"

 

But for take off you try to keep yourself straight until lift-off where you want to inmediately roll to compensate slip. If you will roll, you should not slip.

Edited November 9, 2022 by AJaromir

[maajr57]

Nice job grafspee! So you think the flight model is realistic particularly when things don't go well? During my attempts, the tail would swing INTO the wind and the nose would drop for a prop strike. 

[grafspee]

2 hours ago, maajr57 said:

Nice job grafspee! So you think the flight model is realistic particularly when things don't go well? During my attempts, the tail would swing INTO the wind and the nose would drop for a prop strike. 

I'm not sure. i'm not expert on taildraggers.

I performed couple more tests with other planes, like Spitfire , P-47 and Fw190 A8

results are that only Spitfire had tendency to turn in to the wind, and i must say it was almost impossible to turn left while taxing when wind was from right side, and at take off Spitfire was pulling in to the wind so hard that minimal power made rudder almost ineffective it was at the verge of capabilities to take off with 20kts left cross wind.

P-47 and Fw190 acted like P-51 but they were easier to take off but this was after i did couple tries with P-51 so maybe my skills went higher.

Why P-47 and Fw190 and P-51 are pulling away to the wind i don't know

Edited November 9, 2022 by grafspee

[AJaromir]

I think I've found where you make mistake. You need to pull the stick bit more. This will improve traction of tailwhell because there will be higher press on it. Try to keep stick fully pulled until 90-110 mph IAS.

[AJaromir]

2 hours ago, =475FG= Dawger said:

If anything, DCS tail draggers are very forgiving and easier

Advice from old IL2 veteran. Using as wide field of view as possible helps to see the aircraft motion a lot. Then your reaction to motion will be much faster and better.

 

Edited November 9, 2022 by AJaromir

[=475FG= Dawger]

3 hours ago, AJaromir said:

Advice from old IL2 veteran. Using as wide field of view as possible helps to see the aircraft motion a lot. Then your reaction to motion will be much faster and better.

 

 

Actually the real world technique of picking a far distant point works well in DCS for lateral control. 

Edited November 9, 2022 by =475FG= Dawger

[maajr57]

Don't know how to post my tracks. Sorry

I'm thoroughly disgusted at this point. As I said in my opening post, I have no problem in X-Plane. I have also flown normal 45 degree crosswinds in DCS. Here, in what is supposed to be a training scenario, the tail swings into the wind and the prop goes to the right and into the ground without me touching the stick. I understand about Gyroscopic Precession but this is crap. The aerilons should be banked to the left in this scenario and there should be right rudder to keep the nose straight, just like landing in the same scenario. Left rudder when the tail comes up to compensate for the Gyro. So what's the trick to keep the prop from going into the ground?

Edited December 1, 2022 by maajr57

[maajr57]

On 10/31/2022 at 4:01 PM, NineLine said:

I need a track of your issue so I can review, thanks.

I will get a track posted as soon as I figure out how to do it. Thanks for the reply and sorry for the delay. At this point, after watching AJaromir's video, I think the problems begin when I lift the tail. I was trying to do a wheel takeoff rather than a 3 point takeoff. I will get you a track soon. Thx.

On 11/9/2022 at 1:36 PM, AJaromir said:

I think I've found where you make mistake. You need to pull the stick bit more.

Since you are the resident expert, would you please try some 2 wheel takeoffs rather than 3 point in the same crosswind scenario? 

Looking forward to your input. Thx

[grafspee]

On 12/1/2022 at 3:38 AM, maajr57 said:

Don't know how to post my tracks. Sorry

 

 

It is simple, on the bottom of the post edit window 

You can drag file here or choose them from 

At the end on the mission you have option to save track.

If nose goes down i pull stick aft that fix problem.

I would advice to check if brakes aren't applied 

I can't help if i don't know when this nose drops.

Edited December 2, 2022 by grafspee

[maajr57]

Crosswind Takeoff 1.trk Crosswind Takeoff 2 No Stick.trk

Thanks Grafspee!

[maajr57]

Not what I had in mind Grafspee! lol! 

So how do you watch these? My guess is that they need to be copied to the Tracks folder in DCS.

I tried to upload the same files to Youtube like AJaromir but Youtube rejected them, probably because it doesn't know what a TRK file is.

[razo+r]

8 minutes ago, maajr57 said:

Not what I had in mind Grafspee! lol! 

So how do you watch these? My guess is that they need to be copied to the Tracks folder in DCS.

I tried to upload the same files to Youtube like AJaromir but Youtube rejected them, probably because it doesn't know what a TRK file is.

Yup, you copy them to the track folder of DCS and then use the replay function within DCS to watch the track.

[grafspee]

4 hours ago, maajr57 said:

Not what I had in mind Grafspee! lol! 

So how do you watch these? My guess is that they need to be copied to the Tracks folder in DCS.

I tried to upload the same files to Youtube like AJaromir but Youtube rejected them, probably because it doesn't know what a TRK file is.

You can upload in to YouTube only video capture of the game, posting track is different thing and only DCS client can read that.

So if any one is asking for track, you upload those directly in to forum, if you want that ppl can watch what you are doing in DCS without DCS client, you have to capture audio and video track via capture software, i for example use "NVidia experience"  and then you can upload it to YouTube.

Edited December 2, 2022 by grafspee