su-27 performance

[Yo-Yo]

Yo-YO it was the G to altitude chart that Ed followed, but there many other perfomance aspects that cant be matched with SFM, but we hope they could be with AFM. Ill investigate my F-15 book GG right after dinner BBL

 

We always did claim that SFM provides good TRAJECTORY/ENERGY (CG flightpath) model of the real plane, rollrate as well but we never claim that it can provide live short-period behavior (rotations around the CG).

If G vs TAS and altitude and acceleration/climb vs TAS and alt fit the real plane we can consider trajectory model quite accurate.

[Pilotasso]

Im talking about minimum level sustainable flight and climb rates. I have no straight figures though I did fing descriptions of manuevers at certain altitudes and speed that are far out of LOMAC's reach. Pics to follow shortly.

[Pilotasso]

heres some text describing the manuevers:

 

put emphasis on the last 2 sentences of pics 1 and 3

 

Source: Great Book Of Modern Warplanes by Mike Spik and Bill Gunstonn 2003 edition

[Pilotasso]

lol what did you expect? Classified reports? :P

[Force_Feedback]

9750 M/min /60= 162.5, the su-27 has 230-270 M/sec, depending on who you believe. Seems pretty obvious from here on, and the F-15B matches the flanker better weight wise.

[GGTharos]

Thanks again for your answers Yo-Yo :)

 

Are you trying to say that the simulation is correct within its own limitations? :)

I'm not sure how to interpret this - does this mean that there are some factors which may affect performance that are not simulated, but they should only be affecting things like roll and yaw rate at different speeds and altitudes?

 

I'm sorry to be asking so many questions, I am curious; do you have the excess-energy curves for F-15? :)

I was told to also check some other performance like acceleration, and it seems to be too low: again same configuration at 40000', acceleration from Mach 0.9 to 1.3 should be well under 110 sec, but it is more in LO, IIRC.

Again, I refer to F-15C however Su-27 also has this perceived deficiency.

 

We always did claim that SFM provides good TRAJECTORY/ENERGY (CG flightpath) model of the real plane, rollrate as well but we never claim that it can provide live short-period behavior (rotations around the CG).

If G vs TAS and altitude and acceleration/climb vs TAS and alt fit the real plane we can consider trajectory model quite accurate.

[Frostie]

Its all very good ...now lets get back on topic and discuss Su-27:bored:

 

Jees ,its got to a point were im too scared to start a conversation with my gran for fear she'll bring up F-15 problems in Lomac.:chair:

[GGTharos]

Frost1e, wherever you read F-15 here, just read 'F-15 and Su-27'.

 

These aircraft are direct competitors with very similar performance in this respect IMHO and as such this is for both of'em.

[Yo-Yo]

9750 M/min /60= 162.5, the su-27 has 230-270 M/sec, depending on who you believe. Seems pretty obvious from here on, and the F-15B matches the flanker better weight wise.

 

What can be discussed W/O weight info? And please keep in mind that energy climb strongly depends on altitude.

 

 

If you want to compare some charts you want you can find there

 

http://www.airwar.ru/other/bibl/su27mh.html

[Yo-Yo]

Thanks again for your answers Yo-Yo :)

 

Are you trying to say that the simulation is correct within its own limitations? :)

I'm not sure how to interpret this - does this mean that there are some factors which may affect performance that are not simulated, but they should only be affecting things like roll and yaw rate at different speeds and altitudes?

 

I'm sorry to be asking so many questions, I am curious; do you have the excess-energy curves for F-15? :)

I was told to also check some other performance like acceleration, and it seems to be too low: again same configuration at 40000', acceleration from Mach 0.9 to 1.3 should be well under 110 sec, but it is more in LO, IIRC.

Again, I refer to F-15C however Su-27 also has this perceived deficiency.

 

 

Yes you are right: any model is correct within its limitations. That's why AFM was developed, that's why the new generation of engine model is implemented in BS.

 

Yes, we have these curves.

[Frostie]

Or he could just open his mind a bit.

:spam_laser:

[Vekkinho]

OT but here's my remark on Open Falcon's F-16 FM.

 

Cat I vs Cat III:

In OF you can pull more G in Cat III config (9G) equipped with 2X600 gal. Fuel Tanks and rip your wings off than in Cat I clean (6.5G).

 

So much of HFFM and general F4 realism!

 

Enjoy!

[Red Hammer]

Do you people mean that the aircraft did not been modeled with their real performance?

So how big difference there is between the lock on and the real life plane?

[GGTharos]

This is a year old thread. And the Su-27 was modeled with its performance as close to real as the SFM permits.

[cool_t]

I truly feel that the ET is the only thing going for the Su-27, and thats a botched missile.

[Mugatu]

^^^

 

And the datalink.

[cool_t]

^^^

 

And the datalink.

 

Woops I forgot that one, also it can cary bombs.

[Vekkinho]

So can the Flanker in LO if you LOPE it.

 

A-G mode is also implemented just like in case of MiG-29 so if we decide it can carry bombs (but based on RL data) than it shouldn't be a problem in MP!

[Vekkinho]

This is a year old thread. And the Su-27 was modeled with its performance as close to real as the SFM permits.

 

I know it's old but I just had to add my 2 cents on F4's HFFM.

 

Although a SFM but planes in LO "feel" much closer to RL flying than F4 flying does. RL Falcon HUD tapes show more wobble during flight than HUD tapes from F4 where planes seems more stable and sterile.

 

Also high AoA flying in F4 is a disaster, final approach @<150 CAS feels like landing a truck as you have no control as you should have IRL.

 

+ major bug are fully automated flaperons. IRL F-16 pilot can manually controll flaperons thru various deflection angles and that's not the case in F4 where FLCS takes care of everything. One of the most important Falcon trainings IRL is a no-flap landing and takeoff but in F4 flaperons are automatically lowered as the plane start to get dirty (gear lowering). There's no chance ofoverriding FLCS in F4 so if your FLCS fails you have no manual control over airframe as you have IRL. That's like steering a car wtih faulty servo, it's more difficult than steering a car with no servo at all.

 

I believe Pilotasso's brother can back me up here.

[Pilotasso]

I know it's old but I just had to add my 2 cents on F4's HFFM.

 

Although a SFM but planes in LO "feel" much closer to RL flying than F4 flying does. RL Falcon HUD tapes show more wobble during flight than HUD tapes from F4 where planes seems more stable and sterile.

 

Also high AoA flying in F4 is a disaster, final approach @<150 CAS feels like landing a truck as you have no control as you should have IRL.

 

+ major bug are fully automated flaperons. IRL F-16 pilot can manually controll flaperons thru various deflection angles and that's not the case in F4 where FLCS takes care of everything. One of the most important Falcon trainings IRL is a no-flap landing and takeoff but in F4 flaperons are automatically lowered as the plane start to get dirty (gear lowering). There's no chance ofoverriding FLCS in F4 so if your FLCS fails you have no manual control over airframe as you have IRL. That's like steering a car wtih faulty servo, it's more difficult than steering a car with no servo at all.

 

I believe Pilotasso's brother can back me up here.

 

I have spoken a dozen times about flight models with him. While he cannot say much for LOMAC he claims F4 low speed FM is off from reality (I say because no moments of inertia or boundary layers are simulated).

 

Not only that but its a common problem even for training simulators. F4 FM is not much better or worse than some full blown military simulations either.

[Groove]

Please stay on topic. Afaik this threads name is "Su-27 Performance" and not "Lomac vs. F4". And - no - we dont need a Lomac vs F4 thread!

[mvsgas]

I know it's old but I just had to add my 2 cents on F4's HFFM.

 

Although a SFM but planes in LO "feel" much closer to RL flying than F4 flying does. RL Falcon HUD tapes show more wobble during flight than HUD tapes from F4 where planes seems more stable and sterile.

 

Also high AoA flying in F4 is a disaster, final approach @<150 CAS feels like landing a truck as you have no control as you should have IRL.

 

+ major bug are fully automated flaperons. IRL F-16 pilot can manually controll flaperons thru various deflection angles and that's not the case in F4 where FLCS takes care of everything. One of the most important Falcon trainings IRL is a no-flap landing and takeoff but in F4 flaperons are automatically lowered as the plane start to get dirty (gear lowering). There's no chance ofoverriding FLCS in F4 so if your FLCS fails you have no manual control over airframe as you have IRL. That's like steering a car wtih faulty servo, it's more difficult than steering a car with no servo at all.

 

I believe Pilotasso's brother can back me up here.

 

OK, Groove I hope this ok. F-16 pilots do not control flaperons, There is a switch that will lower them but I have yet to met a pilot that requires to lower them or would want to do that for no other reason except an emergency. At any rate I have never seen that in 11 years on the F-16. The flaperons come down to 21 degrees automatically when you lower the landing gear or at certain speed and AOA. Also DFLCC or FLCC do not take care of everything, it is a normal misconception. The pilot tell the DFLCC what to do and the computer adjust what ever flight surface it need to adjust to move the aircraft (depending in many factors; AOA, mach number, etc)but the plane does not fly itself. The F-16 can not land without flaps it is impossible. When the landing gear is lower, the DFLCC does several thing. It reduces the speed that flight control surfaces travel and how far they travel. the speed brakes will only open to 45 degrees instead of 60 to prevent scraping them on the ground on landing and will not allow the pilot to open them until weight on wheel on the nose and it will lower the flaperons to 21 degrees. Pilots can not override the DFLCC or the FLCC. If DFLCC fails you go to back up control and if that fails you are screwed literally. It has been known that Falcon 4.0 (all vercions) has a horrible flight model. I got a chance to fly the F-16 simulator the other day when I was getting certified to run the real jet and let me tell you. Falcon 4.0 avionics are pretty close but the flight model is a joke . It is better that some games do. I wander, How does this compare to the SU-27 computer control? It is a FBW aircraft right? Or is it like the F-15 where you have computers but there are more analog servos?

[RedTiger]

Please stay on topic. Afaik this threads name is "Su-27 Performance" and not "Lomac vs. F4". And - no - we dont need a Lomac vs F4 thread!

 

As someone else mentioned, this thread was necroed from a year ago (Vekkinho, you should know that thread necromancy is a punishable offense! :P ). It got off topic before it was ever resurrected. :lol:

[RedTiger]

I wander, How does this compare to the SU-27 computer control? It is a FBW aircraft right? Or is it like the F-15 where you have computers but there are more analog servos?

 

The Su-27 has true FBW. Like the F-16, its statistically unstable and wouldn't be able to fly without it. It doesn't do the job as well as the F-16 though, as far as filtering out unwanted behavior. The Su-27 will still continue to roll a bit after moving the stick back to the center and requires counter stick movement to stop while the F-16 counters this behavior automatically. I've also heard that there is a very, very small yet perceivable "ramp-up" time between moving the stick and actual movement of the plane.

[GGTharos]

Er, no, the Su-27 does NOT have FBW. Unless you're talking the more advanced versions like Su-27SM, etc, which may well have it. The Su-27 has the same type of ACS as the F-15 does, not an FBW.