F-5 Performance

[Felipe Antonio]

Good mornnig.

I have some doubts about F-5 performance on DCS. In accordance with F-5 manual, performance chapter, the F-5 is capable to reach 7,33g at 5000 ft with 340 kias. But the aircraft barely reach 6 g's. I dont know where is the problem. I make other tests like sutained turn at 5000 ft and this parameters are corrects. To all tests auto flaps was selected.

With this possible error, the F-5 dont have the correct performance and accuracy.

I share the technical order performance page and one video.

You can download F-5 manual on DCS site.

T.O. 1F-5E-1 (F-5E Manual) (digitalcombatsimulator.com)

 

Edited December 25, 2020 by Felipe Antonio

[GGTharos]

I'll run a test myself, but before that a couple of questions:

1) Did you match the GW?

2) Did you set up correct ISA standard day?

[Felipe Antonio]

Yes... I set the the correct weight and ISA. The parameters at 15000 ft and 30000 ft follow correctly the manual but I didnt ajust the ISA parameters to this 2 tests. (Only to 5000 ft). Only the corner speed at 5000 ft dont match with the data performance. I didnt make the acceleration test yet. 

Edited December 25, 2020 by Felipe Antonio

[Malamem]

A friend of ours made the acceleration test and have got the result that it's accurate.

AFAIG, the turn performance bleeding energy can be related to the induced drag at high AoA.

 

The problem reported by yourself is an old question already raised by many of the F-5E real pilots. 

 

Excellent data Felipe.

[bkthunder]

I think the wind bug is still present, so wind will impact the performance of the F-5 depending on which direction you're pointing at... ridiculous but it is what it is. 

Make sure you have 0 wind in the mission.

[PetRock]

FYI there is a known bug about engine thrust being related to ground speed instead of airspeed that I don't believe has been addressed yet. I have also heard there are issues with drag calculations as well. Check the bugs section.

[BIGNEWY]

please include short track replays showing the issue, we can review it then.

 

thank you

[Tiger-II]

On 12/25/2020 at 3:13 PM, Felipe Antonio said:

 

 

 

 

Great to see some data on this! It is my biggest complaint with the F-5. It is supposed to be competent at ACM, but the current flight model requires that more thrust than necessary is required to fly at the desired performance, which in turn burns too much fuel and shortens the fight (fight, not flight) time considerably.

 

Between this and the engine problem when wind is present, are the two biggest items that need addressing, IMHO.

 

I'll try and get tracks tomorrow for a second view.

Edited December 30, 2020 by Tiger-II

[bkthunder]

The wind and engine bugs have been reported, over and over again. Don't hold your breath, this module's FM is as broken as it could possibly be, and nobody has done a thing about it for the past 2 or 3 years. 

[Tiger-II]

2 hours ago, bkthunder said:

The wind and engine bugs have been reported, over and over again. Don't hold your breath, this module's FM is as broken as it could possibly be, and nobody has done a thing about it for the past 2 or 3 years. 

 

I know.

 

Why??!! How are such major problems allowed to persist?

 

This would be one of the best DCS modules if they fixed these problems.

[PetRock]

On 12/29/2020 at 3:33 AM, BIGNEWY said:

please include short track replays showing the issue, we can review it then.

 

thank you

 

Just in case you are asking about the thrust issues (which could be related depending on how the FM is done in the DCS game engine).

 

 

Good luck with the bug hunting and thank you for your attention.

[Jagua]

I did the test with the same condition above, including weight (50% fuel and AIM9s). I didn't get the 7.33 Gs, my maximum was 6.2, but I got the maximum instantaneous TRT (22.3).

The maximum sustained TRT I got (maintaining speed) was 13.0 at 4.4 Gs, as in the data graph.

 

 

Edited December 30, 2020 by Jagua

[Felipe Antonio]

On 12/29/2020 at 8:33 AM, BIGNEWY said:

please include short track replays showing the issue, we can review it then.

 

thank you

I did test again with all standard parameters.

I lost the track of 5k full ammo. I will make again later. (ALL FILES NOW ARE ATTACHED)

 

Tacview-20201231-031043-DCS-F-5E3 performance test - 5k full ammo.zip.acmi Tacview-20201231-030215-DCS-F-5E3 performance test - 5k no ammo.zip.acmi F-5E3 performance test - 5k no ammo.miz F-5E3 performance test - 5k full ammo.miz LastMissionTrack.trk

Tacview-20201231-192519-DCS-F-5E3 performance test - 5k full ammo.zip.acmi

Edited January 2, 2021 by Felipe Antonio

[shadepiece]

Was there any follow up on this?

[Shortways]

Despite all tests above, when doing a tailchase exercise with an F-5E as agressor, it is impossible to stay on his tail during BFM. It simply has more power and/or less drag.

Edited February 15, 2022 by Shortways

[Tiger-II]

On 2/15/2022 at 5:07 PM, Shortways said:

Despite all tests above, when doing a tailchase exercise with an F-5E as agressor, it is impossible to stay on his tail during BFM. It simply has more power and/or less drag.

 

F-5 is AI? It uses SFM and has too much thrust in AB. No thanks to integrity check AFAIK it's now not possible to edit the file if you want to fly online. If you look at the thrust for AB it is double what it should be. Correcting it back gives it the correct performance and it makes all the difference.