stuck on grass

[jackmckay]

Taxiways have at least 1m of hardened soil around its edges not covered in concrete. Its usually grained rock, rolled and packed before concrete layer. Cant dip in there.

[cichlidfan]

That chart is nice but still meaningless since there is no specific test data for the soil next to the taxi/runways.

 

FYI.

 

I just called up a friend of mine who happens to be a retired Command Sergeant Major, US ARMY (26 years). His battalion was a horizontal construction battalion. In other words they built roads and runways. He told me that the terrain along side the runways and taxiways was not, in any way, compacted or strengthened. If an aircraft went off the edge it almost always had to be lifted out.

 

The gravel area you are talking about is probably part of the runway model in DCS. When you are sitting in the grass, you are beyond that area.

Edited November 30, 2017 by cichlidfan

[jackmckay]

This is Russia! :)

[cichlidfan]

Let's assume you are correct and DCS has it modeled incorrectly.

 

1) Assuming the issue is with the Normandy or Nevada maps, it is likely to be a low priority bug.

 

2) If the problem is on the Caucasus map, that is going to be completely replaced soon so nothing will be fixed on the current map.

 

Under those circumstances, your best bet is to taxi slower and steer better in order to avoid leaving the pavement.

 

EDIT: Russia is a big place, with a great deal of different terrain characteristics, and that does not look like the edge of a runway in Georgia. It is a cool video, though, so thanks for that.

Edited November 30, 2017 by cichlidfan

[jackmckay]

https://foxtrotalpha.jalopnik.com/watch-these-migs-operate-from-a-grass-field-like-its-no-1697990135

All fine guys. I like your stories from RL ..but read the article above.

[Fri13]

you want to tell me how you expect 50000lbs of metal and fuel to do something besides sink into the dirt?

 

Leopard 2A4 weights about 55 tons. It has tracks that generate ground force per square centimeter lower than a 75kg adult with a average shoe size. This is why a 55 tons Leopard 2 can easily travel on soft snow or swamp as long it doesn't get stuck by bottom part.

The 55 tons is moved up to 45km/h when off-road (soft terrain) by a 1500 HP engine.

 

A Su-27 engines both generate 12500 kg thrust by both so total 25000kg and the combat load is average 24000kg so in optimal situation engines can push aircraft upwards vertically.

 

The undercarriage for fighters is designed to withstand multiple times the weight of the combat loaded fighter for landing purposes, but that is only at straight vertical momentum.

 

Now, saying that Su-27 in full afterburner, that is generating more thrust than the whole aircraft has mass in combat load, can't move even when wheels are on unpaved ground?

Nope.... If one would lock the front wheel on ground (like build a steel structure that is screwed in ground so it can't move) it would cause the whole aircraft flip over front wheel as long the aircraft can rotate around front wheel axis as the engine generated force is higher than front wheel contact point as that is the new COG, just like an helicopter will flip easily over when one wheel/skeet touches the ground slightly as that is now the COG and all forces goes around it.

 

But we are talking about an aircraft that has wheels, that rotate. On a hard paved ground.

The wheels rotate, the turn and the keep going as long they don't slip nor get stuck (dive so deep to the ground that undercarriage hits the earth) and the whole aircraft really needs to be locked on ground.

 

No, the wheels of the aircraft doesn't have a such friction that they wouldn't roll on ground. We are not talking about low weight, but neither are we talking about small wheels that has so high friction that even full breaks can't hold wheels so firmly on ground as does this "soft terrain".

 

 

physics is not stupid

 

Yeah... it ain't....

 

Why to build a complex arresting hook to F-15 for ground engine testing so it can be hold still with full afterburner, when all that ground crew should have done was to just roll the F-15 over pavement? Shouldn't it just be easier to then attach a tractor to under carriage and pull it out? Or would it require to lift up the aircraft?

 

Sorry but no, that action that is there has something to do with the earth collision modeling so the 3D models gets destroyed by touching ground or rolling when in free flight.

And it is just not mattering for the fixing in old engine versions as you are not supposed to taxi over unpaved areas. So you even keep some players in some order in multiplayer so they don't roll over whatever they want!

 

As long the wheels can roll, that is the friction that the aircraft needs to overcome. Because wheel touches something unpaved, doesn't mean the friction is so high that even full afterburner can't push the aircraft on the move.

 

Oh, hold on... Physics don't lie!!!!

 

 

I believe that man is having far more Kn than any other fighter engine.... Right?

[cichlidfan]

https://foxtrotalpha.jalopnik.com/watch-these-migs-operate-from-a-grass-field-like-its-no-1697990135

All fine guys. I like your stories from RL ..but read the article above.

 

Yes, they can operate from 'a grass field'. However, a grass field does not equate to any grass field.

 

Again, this may be a legitimate flaw (I won't use the word bug this time) in the sim. However, under the circumstances you will, first, have to wait until the new Caucasus map is released and then try reporting the problem, if it still exists.

 

Keep the aircraft on the paved taxiway/runway and the problem will cease to be an issue.

 

The only time I have had an aircraft in the grass was when I over ran a runway. The 21 is has a narrow wheel base compared to the paved surfaces in the DCS modeled airfields. It should not be too difficult to keep the wheels out of the dirt. :)

 

Don't sweat the small stuff, life is too short.

[Fri13]

https://foxtrotalpha.jalopnik.com/watch-these-migs-operate-from-a-grass-field-like-its-no-1697990135

All fine guys. I like your stories from RL ..but read the article above.

 

 

At least harrier too rolls nicely from dirt before turning nozzles downwards.

[jackmckay]

Don't sweat the small stuff, life is too short.

 

True, its too short for being stuck in grass box (with plenty of power available) and loosing precious hours of life for failed startups and retaxing with weird rudder reaction. So damn irritating and unrealistic especially on that updated too-narrow taxiways. Feels like driving a wide car true Brazilian favelas.

 

I hope that that new Caucasus map will behave better but I already took too much of my time this way anyway.

[probad]

read the article? for what? article is typical vapid copypasta with 0 content of its own

 

here's what the article doesn't point out:

-airplanes have no ordinance

-airplanes are lightly fueled for exercises

-strip is grass but nevertheless prepared

 

the uneveness of even "flat" terrain in caucasus is the only thing that prevents you from a safe takeoff although it's technically possible. grass takeoffs are trivial in normandy.

 

True, its too short for being stuck in grass box (with plenty of power available) and loosing precious hours of life for failed startups and retaxing with weird rudder reaction.

how do you keep failing something as basic as taxiing that literally nobody else has trouble with after the first few mistakes

 

the consequences must not be harsh enough

Edited November 30, 2017 by probad

[cichlidfan]

 

At least harrier too rolls nicely from dirt before turning nozzles downwards.

 

Keep in mind that even the slightest downward angle of the jets would have greatly relieved the forces between the tires and the ground. Also, as the jet gains forward speed the weight on the gear reduces due to the aerodynamic lift effect from the horizontal surfaces.

[Fri13]

 

[Fri13]

Keep in mind that even the slightest downward angle of the jets would have greatly relieved the forces between the tires and the ground. Also, as the jet gains forward speed the weight on the gear reduces due to the aerodynamic lift effect from the horizontal surfaces.

 

The lift force is nothing, it is simple forward motion that does help. It is always requiring more energy to get something start moving than keep the motion going. But still it is absolutely silly how it is currently in DCS that prepared airfield and its surroundings are like a quicksand for them and their large wheels gets so high friction that they can't even slide forward by a inch.

 

The under carriage is designed to withstand only so much horizontal force, that you can easily damage them if too much force is inflicted to them. But that is something that should be modeled already that you just break them.

 

As well even if you would hit full breaks, if there ain't enough friction to overcome the engine full trusth, the aircraft will start to slide on ground. And it requires very strong counterforce to cause so strong friction that wheels can't move forward.

 

People should realize that paved airfield is always the preferred landing platform, but as well that unprepared dirt strip is designed to be operational field if required.

Problem being many from FOD to such that you might risk dipping too deep in landing, or you will create a hole to ground after enough landings as there are high forces in landing (and yet they don't just dive inside ground when doing so).

 

When landing, you risk to damage undercarriage. When taking-off, you might not get enough speed and as well risk damaging under carriage.

 

But not having a change to get rolling? It is just absurd!

 

you might be able to do that few times in war time for risky strips, but you are not going to do that for 20 years as in peace time.

[cichlidfan]

Btw, the heaviest BMP weighs less than 20 tonnes which is about what a loaded Mig-21 weighs. Again, lots of tread contact vs. a small amount of tire contact with the ground.

[cichlidfan]

But still it is absolutely silly how it is currently in DCS that prepared airfield and its surroundings are like a quicksand for them and their large wheels gets so high friction that they can't even slide forward by a inch.

 

But not having a change to get rolling? It is just absurd!

 

Perhaps you are correct, and (as I said earlier) there is a flaw in the modelling.

 

Obviously, this is an issue as well.

 

 

It is still a small issue compared to many others and should be given the attention required by it's relevance to the purpose of the sim.

 

Don't walk, or drive, near a body of water, and don't drive off of the runway.

[Mars Exulte]

I assume you're talking about the very old and dated game engine that is being REPLACED RIGHT THIS MOMENT. Because, that makes perfect sense for a pointless, empty headed rant. "Yarrrr, FIX THIS... I mean, I know you're already on it, but .... If I stop to think about that, then I can't rant, now can I?"

 

For reference, on NTTR, you can dip off the taxiway (usually) and move around as long as you're careful (I sometimes take shortcuts... I'm not proud of it, but it's true), but then that's hard, dry sand in the Nevada desert, not dark and possibly wet eastern european Georgia or French Normandy.

 

As others pointed out, armored vehicles are quite heavy, but their weight is distributed over a very large area. Otherwise... Surprise, they also sink.

 

A jet often weighs as much or more as most AFVs, but typically has three relatively small wheels. Why? Because they're supposed to operate from paved runways.

 

 

As for your statement "Russian jets are designed to operate from grass and dirt (or something to that effect)"... NO. They are NOT. They are designed to operate from improvised runways, such as a highway, or perhaps a minimally prepared unpaved runway. If you try to set one down in JUST ANY OLD FIELD it will faceplant. EVERY TIME.

 

For proof of my statement above, please see YouTube, where you can readily find videos of an Su-34, a Tu-22, and probably several other Russian aircraft overshooting the runway and rolling end over end as their gear collapses almost immediately.

[Yurgon]

..taxing on narrow taxiway, slipping out a little bit and pow.. damn plane wheel drops like in living sand.. full afterburner, [...]

 

F16 Crash Oshkosh EAA AirVenture 2011

 

Airbus A320 schießt auf Sylt über Landebahn hinaus

 

Those morons! They just had to push throttles to max or even full AB and then they'd have avoided all that embarrassment of leaving a perfectly airworthy jet stuck in the mud. :megalol:

 

Now I'm not saying ground behavior in DCS is perfect right now. But your comparisons and assertions are pretty far fetched, and the repeated references to entirely unrelated material don't help get your point across, either.

 

Now that you know about the problem, how about you don't taxi off runways? It's not that difficult. Most of them are actually built so that pilots would find it relatively easy to keep their aircraft on them, rather than off.

 

If you have any particular problems with ground handling of DCS aircraft, find the proper forum section and I'm sure people will gladly help you.

[Art-J]

I wouldn't call it a flaw, but rather simplification. The old map seems to have only 3 types of surface modelled - concrete, gravel and soft soil. No option for unpaved but hardened emergency strips that could be found in many Cold-War era eastern airbases.

 

So anything up to clean-config Sabre and the MiG-15 can taxi on the grass, anything heavier cannot. Sometimes a bit annoying indeed. Will this aspect be tweaked in updated map? Maybe, though I wouldn't hold my breath for it. I don't think about it much nowadays, 'cause I just learned to taxi properly :D. Apart from ridiculously narrow taxiways at Vaziani, they're more than wide enough on all other bases on the map.

[jackmckay]

MiG-15 can't taxi on the grass. There was a wreckage on taxiway so I turn to avoid it but one wheel stuck and everything goes back to the beginning.

[Terzi]

Well this is a complicated topic.

 

Thinking about the fact that landing gears has their airspeed limitations, wheels buried in humid ground would easily get broken if you apply too much thrust.

 

Weather the wheels get stuck depends on humidity and composition of the soil, tire pressure area and weight on that tire.

 

How much the tire gets stuck is also important. If the center of the wheel is buried already, there is no way that it will get any further by applying thrust.

[Fri13]

 

Those morons! They just had to push throttles to max or even full AB and then they'd have avoided all that embarrassment of leaving a perfectly airworthy jet stuck in the mud. :megalol:

 

No need to act as moron to make false claims from different situation in videos.

 

Differences are that what is the soil (hardened dry dirt or a by design softened part end of the strip for emergency landing situations!) and what damages you can get to under carriage by entering the unpaved area with various speed by different aircrafts.

 

A passenger aircraft is totally different thing by design than a combat aircraft designed to take off and land in dirt strips.

An american aircraft designed to operate mainly from a clean airfields is totally another thing than soviet that is designed to operate from non-prepared airfield by taxiing from all kind war time shelters etc.

As well there is a big difference between military airfields and civilian airfields. Others are designed and built to withstand a bombing and be quickly repaired and serviced all around it as critical mission in military one is to get aircrafts up in the air and down in operational condition without delays, while on civilian one they need to withstand more weight and more landings and have safety functions for emergency situations and yet air traffic can be routed elsewhere in case of emergency.

 

And none of these are about taking off or even landing (while as you can see Mig-21 landing on dirtstrip) from unpaved strip.

 

And there is a big difference as well in weather is it a rain season or dry season.

 

 

Now I'm not saying ground behavior in DCS is perfect right now. But your comparisons and assertions are pretty far fetched, and the repeated references to entirely unrelated material don't help get your point across, either.

 

If you have a tens of tons in motion, all resting on couple very weak and long under carriage in the mass/length ratio, you will easily snap a such mechanism when it can't anymore roll.

 

But as is said, this is in the old engine if using 1.5, but this is as well case in NTTR map where the surroundings of taxiways has been hardened.

 

 

 

One of the reasons why C-130 is in favor for CIA is that you can land it for short dirt strips and take off as well. Great cargo plain for smuggling and illegal traffic operations with huge capacity.

 

Totally different caliber aircraft, but so is the design and field too:

 

I wouldn't even consider taking off in such field if it would be in DCS way....

[Fri13]

How much the tire gets stuck is also important. If the center of the wheel is buried already, there is no way that it will get any further by applying thrust.

 

It actually can come up as applied force will push the tire upward like a lifting force as the force below wheel is stronger than above (aircraft weight).

Question really is more as you said as well, how much force can the under carriage withstand in horizontal direction and even slight off-axis force can be very serious.

 

But as you said as well, if the top layer of the soil is so soft that it can't support the weight, it can't either generate "lift" and will only slow down.

 

This is one of the reasons why in cars or any other wheeled mobility it is important when sinking that you don't stop as getting back moving takes more energy and you might sink deeper immediately when you stop.

 

But we need to take in consideration that this is now just a full lack of simulation capability to fluid mechanics on ground. But could be interesting to see in next decade a additional feature where on wet weather the soil could be swallowing tires, while on dry seasons not, like when soil is frozen or been dried up. But after weeks of light rain, you just go deep quickly.

 

It is very normal thing in anything. Ie. I can stomp with boots the soil front of my yard as much I want without much effect on summer, or drive around with lawn mower without any trace. But if I do that after a week of raining, already my boots goes 5cm deep and driving on it will leave deep traces. But again on winter time I can't even get a 10kg iron bar through couple cm after some time as the frozen soil is too hard.

[BIGNEWY]

Aircraft belong on runways and taxiways in DCS, but in some cases it is possible usually by reducing the aircraft's weight.

 

Long story short, don't go on the grass.

[Art-J]

MiG-15 can't taxi on the grass. There was a wreckage on taxiway so I turn to avoid it but one wheel stuck and everything goes back to the beginning.

 

Must be fuel load related then. I remember taxiing both MiG and F-86 on the grass just as an experiment after similar topic (one of the many on this subject) popped up somewhere in the forum months ago. I don't remember how much fuel I had, though, so probably not much. Still had to use full throttle to get them un-stuck initially.

 

On a sidenote, I also attended this particular airshow back in the day:

 

h1pndkxI7fo

 

However, it's not a fair comparison, as this grassy strip was hard enough for much heavier Catalina and Dakota!

Edited November 30, 2017 by Art-J

[Tone71]

I've lost so many hours on this "feature" that has nothing to do with RL. ...

 

Seriously? Hours? Something's wrong but I'm not sure it's the grass... :joystick: