[REPORTED] GSPD setting doesn't seem to work properly for TOT sequencing

[Razi]

(Originally posted this is the wrong bug forum, sorry)

 

 

 

I haven't been able to get the GSPD setting to work in TOT sequencing.

 

I set up a simple 2-leg flight with each leg being about 20nm. At 350 GS it takes ~7 (6:53 in the mission editor) minutes to fly. I then experimented setting up different TOT for waypoint 2. It works perfectly if I set only TOT and fly the required GS. I hit the TOT at the TGT waypoint 2 spot on every time as long as my TOT is within the performance parameters of the aircraft.

 

However, if I set a ground speed, things don't work. For instance, I set a ground speed of 400 GS and it required me to fly about 339 GS to waypoint 1 and then the 400 GS to the TGT at waypoint 2, but I arrive 32 seconds early. I've attached a track of this test.

TOT gdsd test.trk

[Ramsay]

I haven't been able to get the GSPD setting to work in TOT sequencing.

It seems to work correctly if part of a longer flight plan.

 

It's crucial to setup TOT, GS, etc. BEFORE you start the flight leg to the IP.

 

I set up a simple 2-leg flight with each leg being about 20nm. At 350 GS it takes ~7 (6:53 in the mission editor) minutes to fly. I then experimented setting up different TOT for waypoint 2. It works perfectly if I set only TOT and fly the required GS. I hit the TOT at the TGT waypoint 2 spot on every time as long as my TOT is within the performance parameters of the aircraft.

 

However, if I set a ground speed, things don't work. For instance, I set a ground speed of 400 GS and it required me to fly about 339 GS to waypoint 1 and then the 400 GS to the TGT at waypoint 2, but I arrive 32 seconds early. I've attached a track of this test.

 

What happens is you hit the IP too early - 20nm at 400GS = 3 minutes, so with a TOT (WP 2) of 16:07, you should hit WP 1 at 16:04 but it seems the FA-18C can't calculate the flight between the airspawn (WP 0) and WP 1 such that you arrive at WP 1 at the correct time.

 

If I orbit after spawning in your mission and setup TOT, GS, etc. before overflying WP 0 so it auto-steps to WP 1 and then WP 2 - I hit WP 2 on time (+/- 5 seconds) and on speed.

Edited February 12, 2019 by Ramsay

[Razi]

Thanks Ramsay, I'll do some more testing. Probably need at minimum a 3 leg sequence to properly test with.

[Razi]

Still no success for me setting GSPD. I added a third leg which made the flight plan about 3 minutes longer. I configured the TOT sequence during the first leg for a TOT of 16:10:00 (10 minutes) to TGT (waypoint 3). Then I flew the required GSPD of 322 kts the rest of leg 1 and all of leg 2. At the start of the third leg I flew the 450 kts I set and arrived at the TGT 48 seconds early.

 

 

So I don't know if I'm not doing this correctly or if my flight plan is not setup properly. I have tried to make the parameters as simple as possible.

 

 

Attached is this second test.

TOT gdsd test 02.trk

[Ramsay]

So I don't know if I'm not doing this correctly or if my flight plan is not setup properly. I have tried to make the parameters as simple as possible.

Interesting, I'm not getting consistent results, if I take control of your track, I get the same - I'll need to test some more before I understand what's going on.

[NineLine]

Let me know what you guys come up with, and send a track, I will report as needed. If I get time later I will mess with it as well.

[Ramsay]

Let me know what you guys come up with, and send a track, I will report as needed.

 

Got it.

 

TL;DR:

 

The TOT route speed doesn't take into account the IP>TGT section will be flown faster (or slower ?), so TOT is early, if a faster ground speed is specified for the ingress.

 

Detail

 

For example,

 

Flight Plan

=======

WP 0 Air spawn (08:00 Local/16:00 UTC)

WP1

WP 2 IP

WP 3 TGT

 

UFC TOT Settings

=====

TGT 3

TOT 16:10:00

GSPD 400

 

The route ground speed is approx. 361 GS, until the IP, after which, ingress is at 400 GS.

 

IP>TGT is approx. 20nm

• 360 GS = 3m20s

• 400 GS = 3 min

 

On reaching the IP :

 

• If you ignore the higher ground speed prompt and continue flying at 361 GS, you arrive at the target on time (+/- 2s) but slow.

 

• If you follow the HUD prompt and accelerate to 400 GS, you arrive at the target early (20 +/- 2s) but on speed.

 

Note: The reason my previous tests worked, wasn't because I overflew waypoint 0, changed settings, etc. rather it was because, by orbiting, I reduced my route time, increasing it's speed so it was closer to the desired ingress speed of 400 GS.

 

Tested in DCS Open Beta 2.5.4.27314, Nevada

[Razi]

Thanks Ramsay, that is what I've been experiencing. GSPD didn't seem to be changing the required GS at all. Wasn't sure if I was setting things up properly or not for GSPD to take effect.

[NineLine]

Ok guys, got a good track for our internal build and replicated the issue. I have reported it and will see what the team says.

[Sharpe_95]

G Speed/ToT Error

 

Hi there,

This was reported back in Feb here: https://forums.eagle.ru/showthread.php?t=232012

 

I wanted to add to this as I am experiencing the same thing, with an additional issue.

 

In my case, along with seeing the same error that Razi saw I am also seeing the following:

 

- HSI set to waypoint and auto selected with sequence (to show waypoint heading bugs in conjunction with flight path on HSI and automatic selecting of waypoints.

 

What I am seeing in addition to Razis points, I have noticed that the selected target waypoint cycles to the next waypoint well before arriving at it (as much as 5nn before) when on all other waypoints it switches over at less than 0.5nm as I fly over and turn to the next waypoint.

 

I think this may have something to do with why the GS/ToT is not working as it seems to think the waypoint is ahead of its actual position?

 

- Hope this helps squash the bug.

 

- Sharpe.