The F-5‘s Aerodynamic Model might need to be polished？

[1130]

When I do researches on F-5E tiger's Landing video records, I found most of the "tigers" will do a nose up Aerodynamic Braking, in this video the voice over said 10 degrees (?)  But I found it's really hard to do it in DCS, even I tried to touch down very Gently, the nose gear will "Strike to the floor" within 2 seconds, just like there is a force that pulling it down.   ( I double/hundred checked my brakes are off ),TRACK INCLUDED DOWN BELOW , but  yet I'm not a professional, and I'm lack of documents to proof it further, maybe you the one can provide a little help.   PS. the F-5E must need moooooore LOVE    

 

F5LAND.trk

Edited January 8, 2022 by 1130
Polishing words， Eng not my 1st Language

[RustBelt]

There is a force pulling it to the floor, it's all the weight in front of the main landing gear. You have to preemptively catch it. Easier to do with FFB. 

[LowRider88]

On 1/11/2022 at 5:17 AM, RustBelt said:

There is a force pulling it to the floor, it's all the weight in front of the main landing gear. You have to preemptively catch it. Easier to do with FFB. 

Hi RustBelt,

Do you have tracks or videos to show what you are describing?

The preeemptive FFB catch you describe seems to apply to scenarios when the landing has a bit of force, so the impact of the main landing gear hitting the pavement causing a rotating moment around the gear.

But I have experienced what 1130 describes on the occasions when I am able to pull off a feather light landing, and yet the nose still drops a little after touch down.

I suspect the reason is not FFB, but instead that the wings lose all lift a little after touch down speed.

According to the F-5E manual, touch down speed is about 135 KIAS.

But the manual's Stall Speed chart 6-1, Sheet 2 shows that the lowest stall speed can be about 96 - 100 KIAS (wings level).

So stall speed is about roughly 30 KIAS less than touchdown speed.

So if the stall speed is less than touch down speed, the F-5E should be able to hold about 10 degrees pitch up until the speed degrades from 135 to 100 KIAS.  So maybe the problem here is the higher than expected stall speed.

I plan to test the full flaps down stall speed of the F-5E some time this week, as well as if a 10 degrees pitch hold on landing roll is possible in a completely empty plane.

 

Regarding stall speed < landing speed, this may be similar to what GVad says about approach speed, which may or may not be the same thing.  GVad is a pilot of over 20 years.

 

 

Edited January 15, 2022 by LowRider88

[=475FG= Dawger]

On 1/8/2022 at 3:28 PM, 1130 said:

When I do researches on F-5E tiger's Landing video records, I found most of the "tigers" will do a nose up Aerodynamic Braking, in this video the voice over said 10 degrees (?)  But I found it's really hard to do it in DCS, even I tried to touch down very Gently, the nose gear will "Strike to the floor" within 2 seconds, just like there is a force that pulling it down.   ( I double/hundred checked my brakes are off ),TRACK INCLUDED DOWN BELOW , but  yet I'm not a professional, and I'm lack of documents to proof it further, maybe you the one can provide a little help.   PS. the F-5E must need moooooore LOVE    

 

F5LAND.trk 331.04 kB · 10 downloads

 

I am able to aero-brake in the F-5. It requires a certain amount of precision that may not be feasible on a normal (unextended) joystick but it can be done. 

 

 

 

Edited January 16, 2022 by =475FG= Dawger

[Chuck_Henry]

 

It is possible to aerodynamically brake the F-5E upon touchdown, but it requires quite a bit of finesse. I think the most important tip I can give you is you have, have, HAVE to be on-speed AOA or slightly fast. If you let the jet get slow in the transition and flare, you will need more nose up to arrest the descent rate. That's equals a greater nose down moment than the stabilators have the authority to arrest. Or if you just let the jet touch down hard, it will be a more violent nose down moment, which again the stabilators cannot arrest.

The transition is the hardest part, and I really believe it requires a ton of "batting practice" to feel when the jet is getting low on energy. There are multiple techniques on how to fly it. Crack-shift-idle-flare works, so long as you can consistently feel how much power you're cracking out. I prefer constant pull to the threshold - that is, at the start of the runway underrun, begin steadily pulling the throttles back to hit idle right as you cross the runway threshold. At the same rate, add aft stick pressure to keep the descent rate steadily decreasing until you touch down as lightly as you can manage. Shifting your eyes to the end of the runway (typical airplane technique) or out to the side (helicopter technique I prefer) helps a lot with judging the flare.

The final bit is anticipating how much aft stick pressure to hold as the main gears touch down. You can't just add full backstick, or you risk bouncing the jet. You also can't just hold what you had in the flare since the nose down moment will overcome that. Again, just practice.

Edited September 6, 2022 by Chuck_Henry
Updated broken link to video

[Tiger-II]

I think the F-5 is not quite balanced correctly on its mains. The pitch down seems too strong, suggesting the CoG is slightly too far forward of the main gear.

[LiquidGER]

Just wanted to chime in here to give this thread a +1.
I just flew the damn thing for 40 miles landed my F-5E with no wings after ripping them off in an Over-G maneuver.

I don't think this is accurate  

[Dragon1-1]

Multiplayer? Known issue with damage visuals desyncing from actual damage. 

If SP, then it's definitely a bug.

[Quati]

On 7/18/2022 at 5:43 PM, LiquidGER said:

Just wanted to chime in here to give this thread a +1.
I just flew the damn thing for 40 miles landed my F-5E with no wings after ripping them off in an Over-G maneuver.

I don't think this is accurate  

It has been reported already.

 

[Flappie]

@LiquidGER The F-5E received several DM fixes in 2022 but it seems it was not enough. I'll report to devs.

F-5E wings gone 1.trk

Edited July 20, 2022 by Flappie

[Flappie]

With a little bit of training, I was even able to land, just like you said.

F-5E wings gone 4_landing.trk

[Schmidtfire]

I would like to see the pilot who has the ability to physically pull so many G's that the wing breaks..
It's nonsense. That effect is exaggerated and needs to be fixed. A pilot would g-LOC or loose strength
making it impossible to maintain the extremely high G's necessary to do that kind of thing.
 

[Flappie]

31 minutes ago, Schmidtfire said:

I would like to see the pilot who has the ability to physically pull so many G's that the wing breaks..
It's nonsense. That effect is exaggerated and needs to be fixed. A pilot would g-LOC or loose strength
making it impossible to maintain the extremely high G's necessary to do that kind of thing.
 

Create a separate thread, please. My goal here was to obtain a wingless F-5 -no matter how- in order to reproduce reported bug (which should also have been reported in a separate thread).

[=475FG= Dawger]

5 hours ago, Schmidtfire said:

I would like to see the pilot who has the ability to physically pull so many G's that the wing breaks..
It's nonsense. That effect is exaggerated and needs to be fixed. A pilot would g-LOC or loose strength
making it impossible to maintain the extremely high G's necessary to do that kind of thing.
 

I agree with you.

Many real world fighter pilots agree with you.

Aerospace engineering, physiology and materials science agrees with you.

However, if you persist, you will discover that you must "git gud" and that this "feature" is entirely realistic. 

I have given up any hope of this being reversed.

I have also given up paying money to ED until it is fixed or every other module is treated in the same manner.

Maybe Aerges will entice me to spend money again once I know for sure their new module does not suffer from the same "feature" but even then how do I know it won't receive the same treatment at a later date?

[LiquidGER]

Am 20.7.2022 um 15:08 schrieb Flappie:

With a little bit of training, I was even able to land, just like you said.

F-5E wings gone 4_landing.trk 278.23 kB · 1 Download

Yeah it's pretty crazy.. then on the other Hand, maybe it's aerodynamically accurate? I don't know.
I used differential thrust for Trim mostly and if you're quick enough on the throttle, you can even fly a pretty stable slow approach.
Only issue is that the landing gear is damaged with the wings ripped off, so you have to absolutely butter that thing onto the runway.

I since fooled around with a wingless F-5E and you can even do some proximity mountainflying, once you get used to it.
That's beyond ridiculous imho.


As for Dragon 1-1s Question:
No, I was able to do it in MP and SP without any issues..  you lose control for a second and as soon as you slowed down the spin you have pretty good control of the Airplane (or what's left of it)

Am 20.7.2022 um 12:30 schrieb Dragon1-1:

Multiplayer? Known issue with damage visuals desyncing from actual damage. 

If SP, then it's definitely a bug.

Edited July 25, 2022 by LiquidGER

[Tiger-II]

Broadly speaking I try and avoid rolling while pulling g in any aircraft (sim, or real). It's uncomfortable.

I've yet to accidentally rip the wings off. Going to try flying it again as I haven't flown it since the change(s).

I wish the FM would get some serious attention from ED/whoever wrote it. It had too much drag last time I flew it, but I'm not hopeful it was fixed. Maybe with the impending update it will get looked at? EDIT: see my following post.

Edited August 13, 2022 by Tiger-II

[Tiger-II]

Whoa... I'm fairly sure it is not my imagination but it is flying better than before.

I could actually accelerate very slightly to just over 400 kts and maintain speed in a level +4 g turn - this is definitely something it couldn't do before - and going supersonic wasn't nearly the headache it used to be. I remember it was difficult to get it to go faster than Mach 1.0, but now she'll do it in a gentle climb, as she should! Mach 1.2+ still requires a dive which is also accurate to real-world.

No doubt someone will tell me nothing was changed, but I spent a lot of time flying the F-5 (in DCS) and know it well. These subtle changes to match real-world performance are very greatly appreciated! The real F-5 is no slouch, and finally the sim is close to how it should be!

This brief test was with a clean jet. I'll try it later with a pair of sidewinders.

Edited August 13, 2022 by Tiger-II

[Sarowa]

On 8/12/2022 at 8:23 PM, Tiger-II said:

Whoa... I'm fairly sure it is not my imagination but it is flying better than before.

 

It kinna sounds like you just had a bag on previously?

Granted I've only been flying the Tiger since late 2021, but I only noticed the supersonic wall with at least one bag. With nothing but sidewinders, it'll happily do 1.4 around FL360 in level flight, no dive required.

I also make sure to jettison the center pylon whenever I jettison the center bag by holding down the jettison selected button until I hear two clicks. I don't know if this actually reduces drag but I imagine it can't hurt.

Edited August 15, 2022 by Sarowa

[Tiger-II]

On 8/15/2022 at 10:50 PM, Sarowa said:

It kinna sounds like you just had a bag on previously?

Granted I've only been flying the Tiger since late 2021, but I only noticed the supersonic wall with at least one bag. With nothing but sidewinders, it'll happily do 1.4 around FL360 in level flight, no dive required.

I also make sure to jettison the center pylon whenever I jettison the center bag by holding down the jettison selected button until I hear two clicks. I don't know if this actually reduces drag but I imagine it can't hurt.

 

Well... I totally forgot about that! I will try it [jettisoning the pylon] and see what effect it has!

I put limited stores on the aircraft and flew it, and the problem still persists. I think it is the pylon drag that is wrong. I remember this being an issue on another aircraft as well. The pylons are seperate from the aircraft and have their own characteristics. They add crazy amounts of drag, beyond what they should (yes, they will add some, but not to the extent we see).

Edited August 17, 2022 by Tiger-II