Su-25T vibrations on the ground and seemingly weak nose gear...

I'm not sure whether this should here or in the DCS World 2.5 sub, so feel free to move it if you deem necessary.

Running on OB:

I'm curious whether other people have noticed the extreme amount of vibration while taxing in the Su-25T. Also, the nose wheel feels extremely fragile. (Maybe this is what's causing the vibration at taxi.)

I would say since about a week ago, maybe more, I've noticed the vibration and have not been able to land the 25T successfully, without losing the nose wheel, even when at 320km/h with about 2-3m/s rate of descent, especially if there's a cross wind. I've also lost the nose wheel under braking whilst taxing.

320kph seems to high, at what weight are you landing? I normally pass the runway threshold at around 300kph and touch down around 275kph. Try this, no weapons, no gun ammo and only 40% fuel. Are you still breaking the landing gear on touchdown?

320kph seems to high, at what weight are you landing? I normally pass the runway threshold at around 300kph and touch down around 275kph. Try this, no weapons, no gun ammo and only 40% fuel. Are you still breaking the landing gear on touchdown?

[ATTACH]191615[/ATTACH]

I'll modify my parameters and test again. Each of my recent landings was with about 40-50% fuel and winchester.

umkhunto, check my thread of similar concern:

https://forums.eagle.ru/showthread.php?t=215409

Currently modeled nose wheel is very fragile so be extra careful and keep your rudder inputs minimal.

As for vibrations I see nothing wrong unless of course you already lost some wheel.

Thanks, I'll have a look.

I fly the 25T a lot.

#1 Landing speed is 250/280kmh. You're way over. Waaay over.

#2 You should land with the nose raised a few degrees, which is hard to do at that speed. The nose is for steering and supporting the front, not absorbing shock from landing. That's why the rear gear are several times larger than it is.

#3 The heavier you are and faster you're moving the more important it is you make a gentle and very controlled touchdown. You are coming down too fast for 320kmh and damaging the gear.

#4 There's a thing called friction. It causes heat. When you land at this much higher than safe speed and lock up the brakes they overheat and the tires blow or catch on fire. This is because you're going too fast. -edit High speeds are enough to blow tires all other considerations aside. The plane weighs 30,000lbs+ and you're traveling over 200mph. They're not racing tires.

#5 You don't use the brakes to stop on a Russian aircraft. That's what the drogue chute is for. But you have to slow down first or you'll rip the chute off when you deploy it.

#6 Crosswinds aggravate all of the above. Use the correct runway for the wind direction you have (read the weather data when the mission starts, it's not just decorative) and if necessary use a different airfield.

#7 You're not using flaps most likely, because 320kmh and full flaps makes the plane very floaty. I you are using flaps, you're probably tucking the nose in and collapsing the gear. See #2.

TLDR

The game is fine, the nose gear is fine, your landings suck. 300+ kmh is 'battle damage and can't lower flaps' kind of situation.

Proper landing: Full flaps, nose raised 5-8 degrees, 1-2ms sink rate, touchdown on main gear at whatever speed gives you that, usually 270ish let the plane stabilise several seconds, then pop the chute. Only brake at the very end IF necessary so you can taxi to parking.

TIP: When you land you should be able to hold the nose off the ground, apply full power and climb back up immediately. If you are cannot do that, you are landing too hard.

...the nose gear is fine, your landings suck...

:) Yes, but tell us what you really think.

Another thing - If you're not using the chute, don't try to brake and turn at the same time - makes sense if you think about it - you throw all the weight on the front wheel then peel off the tire by turning it sideways - so pulse your brakes : Brake hard, release and correct track, brake hard, release and correct track.

This is a very low quality video, but it's landing the SU-25T at 19500kg.

Because it's so heavy, you'll see from the HUD I came in a bit low and fast, but if you look carefully at the status bar you can see that as I crossed the threshold I cut the engines and flared, and touched down at 260 km/h. There's a lot of runway left after stopping. I tried without using the chute, and at 19500kg that resulted in a stop much further down the runway :-) - but apart from pride (or a big crosswind), why not use the chute ?

OmWJNuIJYaY

Because it's so heavy, you'll see from the HUD I came in a bit low and fast, but if you look carefully at the status bar you can see that as I crossed the threshold I cut the engines and flared, and touched down at 260 km/h.

I see 280 @touchdown. And it's not extremely heavy if it's 30% fuel :)

...Stuff...

I'm not convinced. A week or two ago I could land it fine, in low visibility with heavy cross winds. Now I can't, without killing the nose gear. The biggest tell tale is the massive vibration I now experience while taxing from the ramp. All the guys I fly with complain about the exact same thing. Vibration during taxi, nose gear made of paper.

I'll make a track when I have a chance.

Unfortunately until Harm it's the only real option for SEAD, which is the only reason for me to fly it. I prefer using the 25A for redfor bomb truckery.

You're welcome to not be convinced, but the landings you describe are still too fast and too hard whether you like it or not. I land in crosswinds, a couple times fairly hard and have yet to damage the gear since I started flying again two weeks ago. Difference : I land 50+ kmh slower than you.

Whether or not you're landing too fast isn't debatable. You are. Read the manual or any reference to Frogfoot landing speeds. A delta wing MIGHT land at a speed in that range, but still slightly on the high side I think.

The fact you're having this problem and I'm not is pretty indicative I'm correct. That your friends also scrub their landings is irrelevant, as is whether you think you got away with it before. Reduce your speed about 50kmh and watch your problem magically disappear. Or don't and keep pretending it's not your fault. Doesn't matter to me =) I'll just taxi around the wreckage

I see 280 @touchdown. And it's not extremely heavy if it's 30% fuel :)

You're funny :-)

If you look carefully again you'll see it's a full internal load of fuel (3790 kg), and a full load of 32 FAB-100, which puts the weight at 4 kg below the maximum permissible weight.

A quick Google search produced 210kmh for Su-25A and 230kmh for the T. I'm a bit over (250-270), but I don't flare on landing, I just come in nose high. Homeslice here is roughly 100kmh over on his landings... but, yeah it's TOTALLY the poor simulation in DCS and weak nose gear. Not excessive speed at all. Ridiculous notion :p Note : A fully loaded 25T takesOFF at less than 320 =)

If you look carefully again you'll see it's a full internal load of fuel (3790 kg), and a full load of 32 FAB-100, which puts the weight at 4 kg below the maximum permissible weight.

Ahh, ok, this fuel indicator is misleading :)

I'm not convinced. A week or two ago I could land it fine, in low visibility with heavy cross winds. Now I can't, without killing the nose gear. The biggest tell tale is the massive vibration I now experience while taxing from the ramp. All the guys I fly with complain about the exact same thing. Vibration during taxi, nose gear made of paper.

 

I'll make a track when I have a chance.

 

Unfortunately until Harm it's the only real option for SEAD, which is the only reason for me to fly it. I prefer using the 25A for redfor bomb truckery.

Out of curiosity, is this just happening in:

1) MP?

2) on a particular map?

3) at a particular airbase or airport?

Ahh, ok, this fuel indicator is misleading :)

:) it is.

I'm curious whether other people have noticed the extreme amount of vibration while taxing in the Su-25T. Also, the nose wheel feels extremely fragile. (Maybe this is what's causing the vibration at taxi.

The shaking was added just a little before 2.5 IIRC. It's just for "immersion". It's supposed to make you "feel" the runway/taxiway. If I was shaking the bad in a real aircraft while taxing on pavement I'd take it back to maintenance or never take that taxiway again. It's the same as getting the shaking when getting hit or being near an explosion, nothing changed as far as the aircraft is concerned. I personally hate the vibration because at frame-rates under 100hz it's almost nauseating. I wish programmers and game designers would realize that you can't shake a virtual camera in the way you might get shaken IRL. The frame-rate affects that movement you see in a very negative way.

I've flown the 25A and 25T plenty since they implemented that and I've not broken the steering once. The 25's nose wheel has always been very fragile. You cannot make sudden movement of the steering and you cannot take turns fast. If you are breaking the steering on crosswind landings either you are exceeding the crosswind limitations or you are being too rough with rudder inputs. Also, don't use the drag chute with strong crosswinds.

This for Su-25A, but the technique is quite similar for Su-25T. 500 kg of Fuel, 2xS-13, Empty drop tanks, landing by the RL manual numbers: 260-280 km/h above inner marker, 220-240 km/h touchdown on main landing gear, aerobrake until 180-190 km/h:

I fly the 25T a lot.

 

#1 Landing speed is 250/280kmh. You're way over. Waaay over.

 

I agree 100% with Zhukov on all the points he makes. Also try not to use too much steering until you slow way down. Otherwise you will blow a tire

i see lots of responses to how to land the 25t but not a lot if anything about the taxiing issue,

it looks like in sitting on a pneumatic drill, actually feels like the tire has blown out.

i get that runways are not billiard table smooth and expect a little roughness, but the 25t is seriously exaggerated.

i see lots of responses to how to land the 25t but not a lot if anything about the taxiing issue,

In the thread below this one ;) https://forums.eagle.ru/showthread.php?t=174009

Check out my video. I talk about the taxiing issue and you can see for yourself. It's not that bad. You can spend 5 minutes googling and find excellent Su-25 taxiing footage. The sim is SPOT ON.

If you are breaking the airplane on landing, you may need to re-examine your technique. Notice how the pilots bring them in very very softly even aerobraking. Try to do the same.

And notice the shaking on landing? It's actually softer in the sim.

Also take a look at the reflections in the HUD. I would say ED got it right.

Actual here

My video here

https://youtu.be/gFvKIOS40ZY?t=195

It's not the plane shaking that's the problem, it's the CAMERA shaking in a somewhat ridiculous fashion. In rl your eyes somewhat auto stabilise. Your view doesn't shake like that in the airplane. The youtube video is a camera hard mounted to the dash, causing the view to shake in the same fashion as in the game. Camera on dash =/= your vision, it's not hard to grasp, though whoever added this stupid shaking fails to have made that distinction.

As for the hud reflection, the reflection isn't the problem, it was always there in 1.5.8 too, but the switch to DS rendering broke the textures for all the unupdated aircraft, like the 25s, and at one point the MiG-29 which has since been fixed (unless that's a mod I'm using). It is not a conscious decision to render it the manner it currently displays, it is a holdover baked texture from the previous rendering engine which looks terrible with the new engine. That is why the windscreen on the Ka-50 is borked, the hull on the 25A has a weird flat reflectivity, etc. It is something unintentional that needs to be fixed, not 'a feature', i.e. an old unupdated texture incompatible with the new PBR standard.

I disagree. Looks just fine to me. Go fly a shaky plane and try to focus on a needle. Reflections are spot on.

Look at the pilot. He shakes too in the video...lol

And do you hear all the noise when the nose gear touches down? I think Ed should make it rougher.