Su-27 Open-Beta chit-chat and first impressions!

[ruddy122]

Hi Everyone,

 

Personally, I believe the new Su-27 is fine for now.

 

One of the unique characteristics of the ED folks and what I have seen with 3rd party guys like Leatherneck Sims is that they will respond to feedback and will try their best to update their products in the next release.

 

The ED folks have seriously tried to take the video game perfrmance out of the FC3 Su-27 and try to add more realism by adding limits on how far the aircraft can be pushed. Complex simulators from civil airliners to hi performance jet fighters are constantly updating their flight models which take time (years as a matter of fact) and lots and lots of money (millions of dollars) to achieve the level of realism demanded by the customer.

 

What I've seen from the Su-27 beta is that you need a gentle hand, need to stay ahead of the aircraft, and you need to understand the limitiations of the model to effectively employ the aircraft. These are the same principles any real pilot will use when flying Cessnas to heavy airliners and fighters. Eagle Dynamics will fix the bugs but it will take time.

 

Cheers

Lucky

Edited November 9, 2014 by ruddy122
spelling grammar error

[mvsgas]

For USARStarkey and others, what F-15 engines are modeled within DCS? PW-100( + sub-variants), -220( versions) or the -229? Which version versions was used to achives mach 2.6+ in real life? I believed that was mention. I ask because how can we compared the RL with DCS if we do not have a basis to compare it.

 

To anyone,

The only referance I have for the SU-27 is the SU-27SK manual found online. How close is this to the modeled SU-27 in DCS? Considering the SU-27 module is a beta for one and two thta is not a Full DCS module ( like A-10C, P-51D, etc.)

[GGTharos]

They're -220's, which version exactly I don't know. I can tell you that the charts are from '90 or slightly after '90, as far as I know.

 

As for the M2.69, that was the NASA F-15, and I know that they've worked on engine modifications in the past, so that aircraft might have engines that are tuned ... differently.

 

Regarding the Su-27, I don't think you'll find the data it's tuned to online. Just a hunch.

[Esac_mirmidon]

Why after a vertical tail slide the Su-27 enters always in a inverted flat stall? What i'm doing wrong?

[BIGNEWY]

attach tracks, it is the best way to see the issue you are having or creating :)

[BIGNEWY]

When pressing "S" (Stabilization key) the aircraft immediately pitches down and enters an unrecoverable spin. Definitely unsafe and repeatable. 1.2.11. Also I believe last update, main gear does not retract, and indicator shows that all wheels are down, and no "Gear Down" warning is given either, track included.

 

It seems to me you were going to fast to retract your gear

 

Yep did so, with the gear one, I'll make one with the S issue and upload as well.

 

EDIT Updated with track file, also unable to eject (CTRL E E E) from aircraft

 

ctrl e is working fine for me, check your bindings.

Edited November 9, 2014 by BIGNEWY

[SimFreak]

When pressing "S" (Stabilization key) the aircraft immediately pitches down and enters an unrecoverable spin. Definitely unsafe and repeatable. 1.2.11.

 

Do positive trim before attempting to turn off stability augmentation system.

[BIGNEWY]

try retracting your gear before 450, just an observation but worth a try.

[Weta43]

If I trimmed the su27 with flaps down to level flight and then pull up the flaps, why is the su27 lift up the nose to the sky? Mustn't it be revers? Drop the nose slow to surface?

 

because the flaps are quite a long way behind the COG, and so while they provide lift, they also tend to rotate the nose down. whe you retract them, lift goes down, but the lane pitches up.

[Weta43]

CTRL +E+E+E won't work if you're unconcious (or dead because the blood vessels in your head have exploded..

 

"S" will not cause a violent pitch up or down if you remove trim (CTRL + T), and neutralise the stick before diengeging the CAS.

 

Violent pitching when the CAS is engaged and these conditions are not met is not a bug. The death spin might be :)

[Weta43]

"pressing S and leaving it on which causes the issue of excessive down trim and without stick input"

You have no input, the CAS does. When you turn it of - it stops making that input. If it's trying to hold the nose down, the nose will pitch up, if it's trying to hold the nose up, it will pitch down. If you remove trim and neutralise the stick - it's not making any input and so you won't ntice when you turn it off.

 

Not that it should matter, as it seems to me that if you operated your flanker beyond its thermal and stability limits on an operational basis (assuming the FCS would let you without modification) you wouldnt be operating very long since do such a thing would cause failure due to over stressing the air frame. Its like operating a engine beyond its design limits. You can do it, but you wont have that engine very long.

 

I'd still say that even with a perfect FM, if you perform tests that are physically impossible to perform in real life (airstart at 13000m & 2500km/h) you can expect to see results that are never seen in real life.

 

but back to the point above...

 

My understanding is that for much of its flight envelope the max speed fo the Su-27 is set not by the ballance between thrust and drag, but by (as you've mentioned) thermal and structural limits.

 

Exceeding those limits will carry a risk of sever damage to the aircraft, the possibly death.

If, in reality, no-one has ever done something because doing it would destroy the aircraft and has a high probability of death, that isn't the same thing as saying that a SIM's FM shouldn't allow it to be done..

 

I do agree that if flying at M 3.3 would cause parts of the plane to disintergrate, you shouldn't be able to do it in the SIM, but (like there being no consequences in the Beta to pulling >30 G by turning off CAS and slamming the stick back ) if the engines will fail at some speed well below that, it doesn't necessarily mean the FM is off, but it definatley highlights a problem with the damage modelling...

Edited November 9, 2014 by Weta43

[SFJackBauer]

So your argument is that the feature that DISABLE THE PITCH AUGMENTATION should somehow compensate for trim? Bizarre.

 

Changing subject, is it normal that my Flanker tries to auto-wing-level? Autopilot is not engaged, trim is neutral.

[Godzila]

Didn't have time to write first impressions. I like it a lot. I am not sorry for downloading open beta just for this. First time in a sim that I really felt that i fly something big and heavy. It feels like plane is trying to kill you all the time, but so rewarding to fly. Landings are a lot easier because plane is gliding at low speed instead of flying on rails. I successfully entered inverted spin of death many times, even without disabling FBW. I don't know if it is really irrecoverable situation. It appears to have some bugs, but this was the module that I wished for the most. I hadn't have time to dogfight yet, I only did some free flying. Most of the time in DCS for me was in this, mig29 and Su-25T, so this is really big step forward for me.

[uboats]

how does the stick control in trim mode work? Didn't notice anything difference after engaging it (I assigned a key and pressed it, if this could engage that mode).

 

Another thing is that, the main gears have a large latency (sometimes nose gear is up, while main gears still in extract status) after pressing G to require gear up.

 

I also experienced heavy head up tendency after taking off (once IAS > 400), is this normal?

[golani79]

For stick to trim you have to hold down the button and move the stick to the desired position - once reached you can recenter your stick while still holding the button. The stick in the plane then stays at the trimmed position.

[Weta43]

"I also experienced heavy head up tendency after taking off (once IAS > 400), is this normal?

"

 

The flaps are a long way aft of the CoG, so while they provide lift, they also cause the aircraft to pitch nose down. When you retract them, there's less lift, and the nose stops being pitched down - so it appears to rise and you have to re-trim.

 

Try landing and you'll see the pitch induced as the flaps extend.

[LJQCN101]

The flaps are a long way aft of the CoG, so while they provide lift, they also cause the aircraft to pitch nose down. When you retract them, there's less lift, and the nose stops being pitched down - so it appears to rise and you have to re-trim.

 

Try landing and you'll see the pitch induced as the flaps extend.

 

I don't know much about the FCS control laws of SU-27 but when FCS is in TAKEOFF-LANDING mode, does it suppose to hold a zero pitch rate if the stick is in neutral position? Or in other words, does it operate as a pitch rate command system?

[USARStarkey]

You have no input, the CAS does. When you turn it of - it stops making that input. If it's trying to hold the nose down, the nose will pitch up, if it's trying to hold the nose up, it will pitch down. If you remove trim and neutralise the stick - it's not making any input and so you won't ntice when you turn it off.

 

 

 

I'd still say that even with a perfect FM, if you perform tests that are physically impossible to perform in real life (airstart at 13000m & 2500km/h) you can expect to see results that are never seen in real life.

 

but back to the point above...

 

My understanding is that for much of its flight envelope the max speed fo the Su-27 is set not by the ballance between thrust and drag, but by (as you've mentioned) thermal and structural limits.

 

Exceeding those limits will carry a risk of sever damage to the aircraft, the possibly death.

If, in reality, no-one has ever done something because doing it would destroy the aircraft and has a high probability of death, that isn't the same thing as saying that a SIM's FM shouldn't allow it to be done..

 

I do agree that if flying at M 3.3 would cause parts of the plane to disintergrate, you shouldn't be able to do it in the SIM, but (like there being no consequences in the Beta to pulling >30 G by turning off CAS and slamming the stick back ) if the engines will fail at some speed well below that, it doesn't necessarily mean the FM is off, but it definatley highlights a problem with the damage modelling...

 

The problem is two fold:

 

1. The eagle is constrained to its structural limits, the flanker is not.

 

2. Pointing out that there have been cases of airframe's exceeding their limits on occasion in RL is not a justification for wanton allowance of unrestricted flight. In real life, doing these things could kill the pilot or reduce the life of the air-frame so that it is unflyable in a very short period. The problem with just allowing these things is that they can be abused much more easily in a game than in real life. A real pilot would have to be very mindful of these parameter lest he ruin his plane or kill himself in the process. It's not all that different from WW2 planes having compress-ability limits. On a P-51 the limit is 505mph for a dive at low alt, but you can actually go faster before compressing. However, if you do this you run a very real risk in game of killing yourself. Not so with the flankers structural limits right now---you just exceed them with no regard to the consequences......until 2121mph which might not be possible from ground start. What is more some limits are most likely not something that could be modeled as a issue in game but would certainly be an issue IRL. For example, we know that both the Eagle and the flanker can exceed their structural/stability/thermal limits to some extent. If you take a plane beyond its designed speed limit, you would most likely cause permanent damage to the air-frame. The damage could result in immediate performance losses or being rendered un-airworthy in the future. Pilots here have no such concern. Im not implying that evey RL concern should be modeled in game, be in the case of air to air performance metrics, it absolutely should.

 

3. Afterthought: What would be really interesting would be to know if the CAS system on the Flanker and Eagle would even allow these limits to be exceeded by the pilot. It is clear that many elements of both PFM planes CAS/FCS are not working properly. The un-commanded roll on the EAgle is one example. Do we even know if the CAS would let a flanker pilot exceed the limits by default?

[pyromaniac4002]

I do agree that if flying at M 3.3 would cause parts of the plane to disintergrate, you shouldn't be able to do it in the SIM

 

The Flanker just doesn't do Mach 3.3. Forget making it disintegrate from heat, it shouldn't be getting anywhere near that speed to begin with regardless of loadout.

[BitMaster]

For some reason I can't get mine faster than 1160-ish km/h without difficulty on a level flight

 

inverted flat spins everywhere...

 

 

raise flaps !

 

 

Bit

[BitMaster]

If I trimmed the su27 with flaps down to level flight and then pull up the flaps, why is the su27 lift up the nose to the sky? Mustn't it be revers? Drop the nose slow to surface?

 

 

This depends on where the point of lift moves to when deploying flaps, with some airfoils it moves forward = nose-up, on some AC it moves back = nose down. it's a matter of Airfoil and current CG. it is not static nor simple on some AC, dunno for the Su how sensitive on CG the nose is on flaps.

[theropod]

"I also experienced heavy head up tendency after taking off (once IAS > 400), is this normal?

"

 

The flaps are a long way aft of the CoG, so while they provide lift, they also cause the aircraft to pitch nose down. When you retract them, there's less lift, and the nose stops being pitched down - so it appears to rise and you have to re-trim.

 

Try landing and you'll see the pitch induced as the flaps extend.

 

if you use ffb stick decrease trimmer force to %30 or 40 and uncheck swap axis.

no more head up after take off.

i had the same problem but now my plane is stable in flight.

not: my all dcs aircrafts had the same problem(after takeoff nose up,bank left ....)

maybe that can help you too

Edited November 10, 2014 by theropod

[theropod]

 

I also experienced heavy head up tendency after taking off (once IAS > 400), is this normal?

 

if you use ffb stick decrease trimmer force to %30 or 40 and uncheck swap axis.

no more head up after take off.

i had the same problem but now my plane is stable in flight.

not: my all dcs aircrafts had the same problem(after takeoff nose up,bank left ....)

maybe that can help you too

 

sorry wrong for quote ,now corrected:)

Edited November 10, 2014 by theropod

[MoGas]

I really like the SU-27 now, with the FM. Took a bit tuning the curves and deadzone on the stick, but I have to say, I like it!

 

I couldnt fly the Flanker proberly with the FC3 flight model, joystick settings. Then I switched over my F-15C settings, was much better, and with a bit fine tuning, it flys like beauty.....She needs alot trim attention, but I guess this is how she flys.....

[Ragnarok]

I really like the SU-27 now, with the FM. Took a bit tuning the curves and deadzone on the stick, but I have to say, I like it!

 

I couldnt fly the Flanker proberly with the FC3 flight model, joystick settings. Then I switched over my F-15C settings, was much better, and with a bit fine tuning, it flys like beauty.....She needs alot trim attention, but I guess this is how she flys.....

I think the reaction speed trim on digital inputs a lot slow. On my G940, the axis of trim would be ideal, but it worked only in fc2 :(