Force Feedback stick force unaffected by airspeed

[nairb121]

When flying the DCS F-5E with a force feedback stick, the forces on the stick remain constant for a given displacement regardless of airspeed. This is inaccurate - the F-5E has an artificial feel system which should provide longitudinal (pitch) stick forces proportional to g. Increased airspeed results in more g for a given deflection - therefore stick forces should be higher at greater airspeeds.

[Bucic]

Thanks for reporting! That's interesting.

[Bucic]

What brand and model of joystick do you use? Any third party FFB effects software?

[nairb121]

It's a Brunner CLS-E. I normally use Brunner's CLS2Sim software, since Brunner doesn't natively support DirectInput FFB, but I recently got BrunnerDX working and wanted to try it out with the F-5E. Until this is fixed though, I'll probably just keep using CLS2Sim instead.

[Bucic]

I wouldn't hold my breath. Most probably the implementation of FFB in DCS relies solely on DirectInput, i.e. the standard. If that's the case, this bug report isn't even valid. I'd do a forum search for Brunner FFB or, even better, contact Brunner directly to confirm the status of DCS support on their end.

Edited January 18, 2023 by Bucic

[nairb121]

BrunnerDX is an external program that uses an Arduino to interface between DirectInput and CLS2Sim, allowing DCS's native force feedback to work with Brunner hardware. I've been using the CLS-E with CLS2Sim in DCS for a couple years, and have only now been able to test the native implementation via BrunnerDX. This is indeed the behavior of DCS's native FFB implementation.

[Bucic]

I'll step aside and wait for ED's response. Personally, I'd need a confirmation using a standard-standard FFB joystick. Too many factors

[nairb121]

Public-release unlimited distribution document linked below provides data on the F-5's longitudinal feel characteristics and loads, starting on page 151 (numbered in document as 122). Of particular note are the charts showing measured stick force per g at various speeds and configurations on 169-171 (numbered in document as 140-142).

https://apps.dtic.mil/sti/pdfs/AD0738625.pdf

[firefox121]

As far as I know, F5 module has not FFB implementation.....only a small force detent in the longitudinal axis to simulate the aileron limiter

FFB modules 

P-51

mig 15 

Mig 21 (not sure)

F-14

Mirage F1 (not working well at this time)

Helicopters modules in trim implementation (holds stick in trimmed position)

Sas Viggen 

none Flaming cliffs module nor new advanced era Aircrafts (f/18, f16,  etc ) has FFB implementation.

Edited February 8, 2023 by firefox121

[Bucic]

3 hours ago, nairb121 said:

Public-release unlimited distribution document linked below provides data on the F-5's longitudinal feel characteristics and loads, starting on page 151 (numbered in document as 122). Of particular note are the charts showing measured stick force per g at various speeds and configurations on 169-171 (numbered in document as 140-142).

https://apps.dtic.mil/sti/pdfs/AD0738625.pdf

This is what I've been looking for all along for the purpose of the simpit thread! Thank you! https://forum.dcs.world/topic/318106-f-5e-simpit-cockpit-dimensions-and-flight-controls/

 

After reading the following document dated 1978: Northrop f5 Cas Study in Aircraft Design - AIAA, document pages 139 - ...

... I have a problem with control system descriptions applicability between F-5A and F-5E. The problem is the AIAA document boasts about significant redesign of the force feel system and the weight bob*. To give you something for scale, the stick control forces changed by as much as 20% between variant X and Y. The problem is it doesn't clearly indicate what those variants were! Those could be:

X - T-38 OR F-5A (early development(NF-5A?) OR F-5A

Y - F-5A or F-5E

I could compare the respective charts from AIAA and the  AFFDL-TR-71-134 (AD0738625.pdf) but the AIAA's doesn't include test conditions description for the force-feel system chart. The only reference is in the bottom part of that chart and it says '78-1186 3Q'

* the funny thing is the AFFDL-TR-71-134 (AD0738625.pdf) does mention the bob-weight but doesn't show it, from what I've seen.

 

Edited February 8, 2023 by Bucic