Ran FCF-A Checks, found issues and

[Below Average]

BLUF: Ran the pilot FCF-A Checks and found numerous systems that are either improperly modeled, modeled partials or just not modeled.

 

Background: While tanking in a popular server the AI took a cheap shot, I broke away and took some damage. The damage was mainly to my combined system and wing sweep actuator and I ended up loosing all combined hyds. I emergency extend the gear and landing with my wings swept to 55 degrees with no flaps. Before I got it on deck I broke out my PCL and through the appropriate EPs. Not everything worked according to the book and became curious on how accurate the HB F-14B really is. I jumped into the FCF-A (Functional Check Flight Alpha profile in chapter 10 of Natops 01-F14AAP-1 1 AUG 2001) checklist as that is the best way for a pilot to check and see if a system is working or in this case modeled properly.

 

The testing:

 

1) Park and Aux accumulators do not rise with combine pressure and have no indication in-flight. Emergency brakes work however and do appear to run out.

 

2) Egen works with 0 psi combine pressure, transfer pump off and flight hyd pressure. Zero combine hyd pressure14 should result in no Egen.

 

3) Egen test... Inop I believe this is a known and in the Heatblur manual. Same goes with the OBC.

 

4) Paddle switch disengages roll n pitch aug switches and does not switch to engine to manual mode and sec modes. As far back as the 1972 preliminary Natops the roll n pitch should only be disengaged momentary when holding the AFCS emergency disconnect paddle. The SAS switches should not move.

 

5) No speed brake stab shift. The gauge indication nor the stab move. The speed break interconnect is not working, not sure if the flight mode part works but the visuals don’t.

 

6) Trim doesn’t go to 9 degrees TED. Not sure why but I am not getting full throw as per the manual.

 

7) DLC trim not accurate and inboard spoiler gauge has an animation issue.

 

8) WRS and DTFO inop (LSXC). I believe the Tomcat we have is a very early B that did not incorporate the Digital Flight Controls that most B’s had later. This is evident by the SAS panel being similar to old As.

 

9) Asymmetrical switch guard doesn’t reset asymmetrical switch back to on when guard secured.

 

10) Auto-relight logic lights of at 42% during on deck checks. Failure or lack of of N2 deceleration logic.

 

NFM 2.8.1: At rpm above 59

percent, ignition is provided if N2 deceleration exceeds

a 5 percent rpm per second rate. Ignition continues for

20 seconds after N2 deceleration falls below the

5-percent per second rate.

 

and...

 

Spool down relight fails (airstart switch not effective, staying above 300 IAS has no effect). Engine indicates a relight witha rise in temps and fuel flows for a half a second then immediately falls off. Only way to restart is with a crossbleed.

 

11) At 35k wing sweep program inaccurate. ..8 IMN = 37 degrees... .9 = 56 .93 = 65. Doesn’t match up with natops.

 

12) No idle lockup. At 1.1+ IMN idle lock prevents rpm decay greater then 2% below mil, when less then mil is selected. Not modeled, important feature on most a supersonic aircraft.

 

13) ECS not properly modeled. Ecs off and dump fail to work, gauge just sits at old position. However when ECS is on normal the cabin pressure tracks properly. ECS has to be on for the cabin altimeter to work. Example: Climb to 15k, shut off ECS, try to dump pressure and the indication will still be 8K. Blow the canopy and it will still be 8K. Turn the ECS back on and now it indicates 15k. Must be a bug.

 

More testing to come..

[draconus]

Yes, our Tomcat is not DFCS equipped and a bit older than 2001 docs describe. Mind it is still EA and WIP.

[sLYFa]

Good catches,a few comments though.

The SAS switched are spring loaded to the off position and solenoid held in the on position. Once they switch to off (which they do upon depression of the emergency disengage paddle), they must be manually moved back to on. The switch from BOOST/AUTO to MAN and engines to SEC does only occur with WoW upon paddel depression (although I'm not sure whether you tried this on the ground or not)

 

The stabtrim shift with speedbrake deployment was implemented earlier. However, it did not result in correctly neutralizing the pitch down moment caused by the speedbrake, so it was removed, along with the speedbrake pitch down moment. This means that the plane behaves correctly (i.e. no pitching moment with speedbrake extension) but not from two aerodynamical forces cancelling each other out like in the real plane but from omitting these two alltogether. HB said this will change someday but is low priority at the moment AFAIK.

 

Looking at the wingsweep numbers you provided, they seem to match up with the appropriate documentation. Or are the numbers you postet what you are expecting and the sim shows different?

[fat creason]

BLUF:

10) Auto-relight logic lights of at 42% during on deck checks. Failure or lack of of N2 deceleration logic.

 

NFM 2.8.1: At rpm above 59

percent, ignition is provided if N2 deceleration exceeds

a 5 percent rpm per second rate. Ignition continues for

20 seconds after N2 deceleration falls below the

5-percent per second rate.

 

and...

 

Spool down relight fails (airstart switch not effective, staying above 300 IAS has no effect). Engine indicates a relight witha rise in temps and fuel flows for a half a second then immediately falls off. Only way to restart is with a crossbleed.

 

12) No idle lockup. At 1.1+ IMN idle lock prevents rpm decay greater then 2% below mil, when less then mil is selected. Not modeled, important feature on most a supersonic aircraft.

 

 

Not sure what the issue is for the first part of 10, if ignition is on and fuel is flowing it will relight at almost any speed above the minimum lightoff RPM. For the second part, there is no Airstart switch on F110 powered Tomcats, that will be removed when we get the proper EIG for the B model. If I recall correctly, you need to be close to 450 KIAS to spool an engine enough to windmill/airstart without crossbleed assistance.

 

As for idle lockup, I've got something in testing but have no documentation on it. Its existence is merely mentioned in the NATOPS but no description on how it works. If you have more detailed documentation on that subsystem I'd love to see it. I may just push what I currently have in the next update.

Edited October 4, 2019 by fat creason

[IronMike]

If I may add, part of these tests also do not function as we do not have most tests, mainly OBC, implemented yet. Thank you for the detailed list, though, it is much appreciated and we'll check it.

[Below Average]

Good catches,a few comments though.

The SAS switched are spring loaded to the off position and solenoid held in the on position. Once they switch to off (which they do upon depression of the emergency disengage paddle), they must be manually moved back to on. The switch from BOOST/AUTO to MAN and engines to SEC does only occur with WoW upon paddel depression (although I'm not sure whether you tried this on the ground or not)

 

The stabtrim shift with speedbrake deployment was implemented earlier. However, it did not result in correctly neutralizing the pitch down moment caused by the speedbrake, so it was removed, along with the speedbrake pitch down moment. This means that the plane behaves correctly (i.e. no pitching moment with speedbrake extension) but not from two aerodynamical forces cancelling each other out like in the real plane but from omitting these two alltogether. HB said this will change someday but is low priority at the moment AFAIK.

 

Looking at the wingsweep numbers you provided, they seem to match up with the appropriate documentation. Or are the numbers you postet what you are expecting and the sim shows different?

 

My understanding from Natops (F-14B, 2001) is the AFCS switch are spring loaded and once paddled off should and do shutoff. The SAS switches shouldn't move unless manual moved. The SAS roll and pitch stability is off when depressing the paddle switch but once released the system comes back, however the switches do stay in the on position the entire time. This is what I gathered from both the F-14B 2001 manual (which is inappropriate as it has the upgraded DFCS) and an earlier Natops from an A (non plus) model.

 

As for the engine modes both sec and manual mode, WonW and WoffW I cannot get the paddle switch to do anything. Now I am basic my research of the F-14B, 2001 manual and would imagine the F-14A+ manual says the same. Unfortunately I cant find that manual.

 

The wing sweep numbers are what the cat does in DCS and not what the manual says it should.

 

Not sure what the issue is for the first part of 10, if ignition is on and fuel is flowing it will relight at almost any speed above the minimum lightoff RPM. For the second part, there is no Airstart switch on F110 powered Tomcats, that will be removed when we get the proper EIG for the B model. If I recall correctly, you need to be close to 450 KIAS to spool an engine enough to windmill/airstart without crossbleed assistance.

 

As for idle lockup, I've got something in testing but have no documentation on it. Its existence is merely mentioned in the NATOPS but no description on how it works. If you have more detailed documentation on that subsystem I'd love to see it. I may just push what I currently have in the next update.

 

For the first part of part 10, as per the Aatops: Note: Failure of the engine to relight above 59-percent rpm indicates a failure of the N2 deceleration auto-relight logic. The issue is the relight is occurring at about 42% which is 17% lower then the allowable limit in Natops. When quickly going to cutoff then idle, the engine flames out and the deceleration auto-relight logic should catch this and start firing the igniters. Normal Engine idle is 62%-78% and in DCS I have normally seen 71% which gives about 12% above the normal start logic (10%-59% with the throttle in idle the ignition will operate). When going quickly to cutoff then idle the engine has 12% to spool down before the normal start logic begins firing, however during the decel the N2 deceleration auto-relight logic should start the igniters and fire them for 20 seconds and stop the engine from decaying below 59% and effectively relighting the engine.

 

So the Airstart switch currently modeled has no effect and will be removed? Id imaging the airstart switch is for the TF-30. Will we get the ignition button on the side of the throttle for the B or atleast an effective binding?

 

The system is supposed to keep the engines at mil while the aircraft is at higher speeds (1.1+ IMN) to prevent inlet buzz and pop stalls. Natops doesn't talk about much besides the AFTC controlling the idle lockup in Pri mode and sourcing the IMN from CADC.

Edited October 5, 2019 by Below Average

[sLYFa]

My understanding from Natops (F-14B, 2001) is the AFCS switch are spring loaded and once paddled off should and do shutoff. The SAS switches shouldn't move unless manual moved. The SAS roll and pitch stability is off when depressing the paddle switch but once released the system comes back, however the switches do stay in the on position the entire time. This is what I gathered from both the F-14B 2001 manual (which is inappropriate as it has the upgraded DFCS) and an earlier Natops from an A (non plus) model.

The manual for the non-DFCS tomcat clearly says that pitch and roll SAS switches move to off with paddle depression (I can't post it unfortunately)

As for the engine modes both sec and manual mode, WonW and WoffW I cannot get the paddle switch to do anything. Now I am basic my research of the F-14B, 2001 manual and would imagine the F-14A+ manual says the same. Unfortunately I cant find that manual.

That should be incorrect indeed

The wing sweep numbers are what the cat does in DCS and not what the manual says it should.

Looking at the sweep schedule diagramm I can read pretty much the values you provided. I assume the values provided in the FCF section are rounded for simplification.

So the Airstart switch currently modeled has no effect and will be removed? Id imaging the airstart switch is for the TF-30. Will we get the ignition button on the side of the throttle for the B or atleast an effective binding?

In the B its actually the backup ignition switch and is exactly that, a lower power backup ignition system for ground- and airstarts. Not sure what you mean by "ignition button"

Edited October 5, 2019 by sLYFa

[Below Average]

The manual for the non-DFCS tomcat clearly says that pitch and roll SAS switches move to off with paddle depression (I can't post it unfortunately)

 

Attached image from non-DFCS tomcat natops.

[sLYFa]

That is most likely from the preliminary manual from 1970. More recent manuals say otherwise

[Below Average]

That is most likely from the preliminary manual from 1970. More recent manuals say otherwise

 

Could you share some more recent yet pre DFCS Natops.

 

Thanks.

[sLYFa]

I can't as per forum rules :/. It appears though as this has been changed sometime during the Tomcat's service life. We will have to trust HB that they did it right for their particular Tomcat.

[Wizard_03]

If I may add, part of these tests also do not function as we do not have most tests, mainly OBC, implemented yet. Thank you for the detailed list, though, it is much appreciated and we'll check it.

 

 

Gonna go ahead and Necro this thread, when should we expect OBC functionality and or the remainder of the ibits like emergency generator in the sim ballpark? I know its probably low priority but I'd love to see that, I only ever cold start.

Edited December 15, 2019 by Wizard_03