investigating Thrust to weight ratio: confused

[Cmptohocah]

10 hours ago, BBCRF said:

Во первых она не аналоговая, а Аналогово-цифровая. Второй момент где там в уравнении СДУ задержка 0.5с?

In English:

Firstly, it is not analog, but analog-digital. The second moment, where is the delay of 0.5 s in the SDE equation?

[DukeAngus]

i know this is an old thread but if there is an "issue" with the mig 29 has to do with drag. it could be that the 29 has to much drag or the other ones have to little drag. take a f15 and the mig 29 go up to 5k and see how far you can glide with each one. i dont know how things are supposed to be in real life. but i do know that an f-15 can fly and land with only one wing, the same isnt true for the 29

[AeriaGloria]

18 hours ago, DukeAngus said:

i know this is an old thread but if there is an "issue" with the mig 29 has to do with drag. it could be that the 29 has to much drag or the other ones have to little drag. take a f15 and the mig 29 go up to 5k and see how far you can glide with each one. i dont know how things are supposed to be in real life. but i do know that an f-15 can fly and land with only one wing, the same isnt true for the 29

Why do you think the same isn’t true for the 29? Just becuase there hasn’t been a mid air collision that took off a wing and the pilot landed safely doesn’t mean it’s just as capable in that respect. It should be even more capable considering the body lift part of the design. I think the body contributes something like a quarter of the lift. 
 

For the FC3 Su-27, it is known that it actually has too much drag, and under performs in sustained turns for instance 

As far as this thread is concerned I wouldn’t pay it much attention. If you look at OP it seems they didn’t take into consideration that it is a twin engine airplane. And did their napkin math using only one RD-33 engine. This being the internet those that are well aware it has two engines we’re happy to argue about MiG-29 thrust when in fact there has never been an issue or reported bug with its thrust that has to do with its power since the new flight model (that I can remember being an issue) 

[DukeAngus]

I am surprised to hear that it is "known " that the Su 27 has too much drag and underperforms in sustained turns. I can dominate any bluefor with the su-27 and the 29 for that matter. it is much harder to kill a 29 or 27 with any bluefor aircraft. I am of course talking about gun Kills.

I shouldn't have wrote that the same wasn't true for the 29,  even though there is no proof that the 29 has the same abilities. looking back at that post, I should have not even brought it up in a Mig 29 section.

[draconus]

27 minutes ago, DukeAngus said:

I am surprised to hear that it is "known " that the Su 27 has too much drag and underperforms in sustained turns.

Hearsay. Nothing confirmed.

[Pavlin_33]

18 hours ago, draconus said:

Hearsay. Nothing confirmed.

I would not really call it "hearsay" as we have that video of real life Su-30 (might be wrong on the type here) that has same engines as 27 and is heavier than the Flanker and yet it accelerates faster. Yes sure, we don't know the OAT in the video, but this is not the only thing that points to potential 27 issues.

[DukeAngus]

 

On 3/8/2023 at 6:35 PM, AeriaGloria said:

Why do you think the same isn’t true for the 29? Just becuase there hasn’t been a mid air collision that took off a wing and the pilot landed safely doesn’t mean it’s just as capable in that respect. It should be even more capable considering the body lift part of the design. I think the body contributes something like a quarter of the lift. 
 

For the FC3 Su-27, it is known that it actually has too much drag, and under performs in sustained turns for instance 

As far as this thread is concerned I wouldn’t pay it much attention. If you look at OP it seems they didn’t take into consideration that it is a twin engine airplane. And did their napkin math using only one RD-33 engine. This being the internet those that are well aware it has two engines we’re happy to argue about MiG-29 thrust when in fact there has never been an issue or reported bug with its thrust that has to do with its power since the new flight model (that I can remember being an issue) 

@AeriaGloria i just came across this  and i guess my original assessment was correct.  it is the same scenario as the f15s' crash as well.

 this video reminds me of a song!

 

[Ironhand]

9 minutes ago, DukeAngus said:

 

@AeriaGloria i just came across this  and i guess my original assessment was correct.  it is the same scenario as the f15s' crash as well.

 this video reminds me of a song!

 

I’m lost. What are these two videos proving or disproving?

[AeriaGloria]

47 minutes ago, DukeAngus said:

 

@AeriaGloria i just came across this  and i guess my original assessment was correct.  it is the same scenario as the f15s' crash as well.

 this video reminds me of a song!

 

No, I don’t think it is the same scenario. This isn’t a scientific test where two things were subjected to the same thing. 

[Ironhand]

On 3/8/2023 at 1:53 AM, DukeAngus said:

...it could be that the 29 has to much drag or the other ones have to little drag. take a f15 and the mig 29 go up to 5k and see how far you can glide with each one. i dont know how things are supposed to be in real life. but i do know that an f-15 can fly and land with only one wing, the same isnt true for the 29

Best distance: 58 km in both.

Best hang time for each:

• MiG-29: 7:50 over a distance of 57 km
• F-15C: 7:30 over a distance of 45 km

Edited March 18, 2023 by Ironhand

[DukeAngus]

@Ironhand how fast did you start out at? what altitude? do you remember how much fuel you had? any Stores on?  did you turn the motors off? or j Did you just have them idling? 

 

[Ironhand]

3 hours ago, DukeAngus said:

@Ironhand how fast did you start out at? what altitude? do you remember how much fuel you had? any Stores on?  did you turn the motors off? or j Did you just have them idling? 

 

Those numbers were generated with your specified altitude of 5 km. Starting airspeed was 800 TAS (625 IAS) with 5 kg fuel each so that engines died soon after start of test with throttles pulled back to idle. My scenario was that you are gliding because you have ran out of fuel. No external stores on either aircraft for added drag.

In the Eagle, the best speed for time in the air seems to be around 280 km/hr in the above scenario. 370-380 km/hr for best range. Those numbers are pretty much in line with what I’ve read the relationship should be. In the MiG, however, both best time and distance seem to be obtained with speeds in the 350-380 km/hr range which seems a bit odd.

With engines at idle and enough fuel to make both aircraft of equal weight, my guess is that the F-15 will significantly outdistance the MiG-29 based on the pitch and sink rate numbers I was seeing. IIRC, the idle thrust of the F-15 in the sim is greater than that of the -29. If it’s sufficiently greater to make its pitch and sink rate numbers similar to the MiG-29’s, then it will definitely outperform it in glide. But that’s an experiment for another time.

Edited March 22, 2023 by Ironhand

[AeriaGloria]

On 3/21/2023 at 4:31 PM, Ironhand said:

Those numbers were generated with your specified altitude of 5 km. Starting airspeed was 800 TAS (625 IAS) with 5 kg fuel each so that engines died soon after start of test with throttles pulled back to idle. My scenario was that you are gliding because you have ran out of fuel. No external stores on either aircraft for added drag.

In the Eagle, the best speed for time in the air seems to be around 280 km/hr in the above scenario. 370-380 km/hr for best range. Those numbers are pretty much in line with what I’ve read the relationship should be. In the MiG, however, both best time and distance seem to be obtained with speeds in the 350-380 km/hr range which seems a bit odd.

With engines at idle and enough fuel to make both aircraft of equal weight, my guess is that the F-15 will significantly outdistance the MiG-29 based on the pitch and sink rate numbers I was seeing. IIRC, the idle thrust of the F-15 in the sim is greater than that of the -29. If it’s sufficiently greater to make its pitch and sink rate numbers similar to the MiG-29’s, then it will definitely outperform it in glide. But that’s an experiment for another time.

 

I’ll compare to the MiG-29 manual and see what’s it’s best endurance/distance glide speeds are 

[Ironhand]

1 hour ago, AeriaGloria said:

I’ll compare to the MiG-29 manual and see what’s it’s best endurance/distance glide speeds are 

Be interested to see what you find. If memory serves, the only chart I’ve seen used faster airspeeds. So I’m certain that the time in the air will be less and, unless ED screwed up their modeling, the distance will be less as well.

[Mateo]

I would recommend to all interested of such comparison of different aircrafts to ensure understanding the basic theory of glide flight.

Just to get the things straight: maximum lift to drag ratio is a one number that allow you determine the range of glide (no wind) and is not related to aircraft mass at all. The mass have the influence just on the speed. Increase of mass will increase the optimum speed. Range will stay the same.

Edited April 27, 2023 by Mateo

[AeriaGloria]

On 4/13/2023 at 11:57 AM, Ironhand said:

Be interested to see what you find. If memory serves, the only chart I’ve seen used faster airspeeds. So I’m certain that the time in the air will be less and, unless ED screwed up their modeling, the distance will be less as well.

In a cursory search all I could find was a comparison of 400/450/500 kmh glide angles. Showing 500 kmh as the best glide speed for range. I might read the section around the graphic later and see if it specifies the 400-450 Kmh as best endurance gliding speed