PSA: F-14 Performance/FM Development Status + Guided Discussion

[Baz000]

44 minutes ago, Victory205 said:

That's because moving the wings is a configuration change.

How did you overcome the horrifying task of trimming an aircraft. Understand that the F14 constantly requires constant corrections, it's nothing different than any other aircraft, including FBW. 

I haven't spent much time in the T45 and don't have the A4, so can't comment on whether they provide positive training, but I get a sense that a lot of folks jump into the complex modules without spending time flying basics, holding altitude, turns, simple configuration changes, etc, without attempting to understand what is transpiring or how to anticipate. Simply turning off the HUD in the F14 and learning to perform the aforementioned tasks will help you understand what's going on, pitch attitudes and power required. I noticed that the gent doing the AOA vs Speed turned on the autothrottles (I think) to obtain his data, which speaks volumes. Almost all pilots I knew ensured that they would first be proficient without aids, because those aids wouldn't be available when it mattered most. 

That you can do it at all is astonishing. The Heatblur gang has a group that impressed me with their ability to get around the ship. My hat's off to the folks who spend the time and energy to get it right.

I'm not gonna lie, I came from the Hornet to the Tomcat... And i'll tell you what I am very glad I did because I am learning so much more flying the Tomcat than I ever did flying the Hornet (maybe because i'm not actually flying the Hornet but i'm more of a "voting member" so to speak)

If you really want to know how I overcame the horrifying task of trimming the F-14, I picked up my FAA Aircraft flying handbook and gave it a good read, I didn't really find much of my answer in there so I opened my next FAA book I had on my shelf... And I remember you telling me that flying the F-14 had alot to do with instrument flying and to be honest... Before now I had not read much in my instument flying handbook until this point because alot of the instruments discussed(or so I thought until I opened it and started giving the analog instruments section a good read) like FMS and TCAS and etc didn't really apply to us in DCS and was more airliner related.

 

There was something in that book that kinda clicked in my head when I was reading about flying using the analog instruments and it translated well to DCS. For one, I had to stop being ham-fisted on the stick and use distinct pressure instead either fore aft or side to side to get the aircraft to move precisely where I wanted. And another thing was actually incorporating an instrument scan routine and changing the scan depending on what parameter i'm changing on the aircraft with my control or power inputs. But always first and foremost referencing the VDI display because it shows the most immediate change in attitude. And then the next to last thing was stabilizing the aircraft in all of its parameters... Stable speed, altitude, attitude, configuration, only giving slight power corrections as needed to keep a constant speed.

And the final thing was learning how to trim properly by gently relaxing the pressure I'm applying on the stick (so it returns back to center in a controlled non ham-fisted manner) trying to minimize displacement as much as possible and only using slight pressures instead while applying generally nose up trim. But when I would relax the stick near almost right at the center point but not quite there yet... I would see, damn the nose is starting to droop... Immediately start applying the same magnitude of pressure I had on the stick as before and giving nose up trim, the goal being that when I take my physical hand off the stick in front of me... The plane in DCS doesn't move, and it is hard to see in DCS unless you have some frame of reference you use like the instruments but I generally look at the horizon relative to the cockpit frame.

Anyways, after I learned all that... Flying the plane in that trimmed state is very easy with just slight pressures on the stick... And of course it takes practice too, but you have to understand your reactions or over-reactions on the controls are having either desired or undesired effects on the flying of the aircraft.

The nice thing about the FAA handbooks is it also explains "common errors" that are observed and offers ways to solve them too. I think chief among them was I was changing my power setting far too much, I had to set it and forget it for a bit so everything could stabilize and then adjust accordingly to hold say 350 kts for example.

Oh, also another thing was trying to work on one flight parameter at a time instead of trying to fix everything at once(with-in reason obviously)... Everything has an effect on each other I looked at it kinda like the idea of stack, line, spacing in formation flying where you prioritize each dimension to reduce variables.

 

I think there is alot of a disconnect between IRL and sim too, for one thing you don't feel the trim forces on the stick, but for another... When I flew a 1 hr intro flight in a T-34B you could barely move the stick an inch in displacement without it wanting to flip the airplane upside-down. I seem to remember the controls were really really touchy (maybe they did that intentionally since it was a traininer, dunno) I barely had to move the stick to get the plane to move and I also didn't feel like I had to fight air against the control surfaces either and muscle the controls around.

Edited November 10, 2021 by Baz000

[LanceCriminal86]

44 minutes ago, Victory205 said:

That's because moving the wings is a configuration change.

How did you overcome the horrifying task of trimming an aircraft. Understand that the F14 constantly requires constant corrections, it's nothing different than any other aircraft, including FBW. 

I haven't spent much time in the T45 and don't have the A4, so can't comment on whether they provide positive training, but I get a sense that a lot of folks jump into the complex modules without spending time flying basics, holding altitude, turns, simple configuration changes, etc, without attempting to understand what is transpiring or how to anticipate. Simply turning off the HUD in the F14 and learning to perform the aforementioned tasks will help you understand what's going on, pitch attitudes and power required. I noticed that the gent doing the AOA vs Speed turned on the autothrottles (I think) to obtain his data, which speaks volumes. Almost all pilots I knew ensured that they would first be proficient without aids, because those aids wouldn't be available when it mattered most. 

That you can do it at all is astonishing. The Heatblur gang has a group that impressed me with their ability to get around the ship. My hat's off to the folks who spend the time and energy to get it right.

Getting my ghetto sim setup for my floor mounted Virpil (including chopping out the front of my seat to clear the stick) and actual rudder pedals has been enlightening for sure. I've forgotten how long it's been since I used rudder pedals, but I need to completely go back to basics on coordinated turns. I guarantee you would be shooting me down with the CIWS on 100% of my attempted passes if you were the LSO.

I haven't personally used it either but it really sounds like I need to get the T-45 mod and focus on those basics. I'd love to see some guided mission sets that replicate basic flight training, formation flying, and around the boat stuff. As you've pointed out there was a lot to learn and *perfect* before pilots even got a CHANCE to get an F-14 slot.

[Sideburns]

1 hour ago, Baz000 said:

I'm not really a fan of mods, for one thing if you have any you don't get any troubleshooting support with DCS until you eliminate them as a potential cause... And my DCS already gives me plenty of problems at times without introducing any new ones to it.

It's fairly easy to disable the mods using the built in mod manager, I have no issues running the T45 or A4c mods but I do have quite a stable system and DCS install.

[Baz000]

1 hour ago, Victory205 said:

Almost all pilots I knew ensured that they would first be proficient without aids, because those aids wouldn't be available when it mattered most. 

If I remember what read a long time ago correctly, wasn't it like pilots were not even permitted to use auto throttle until 100 manually flown traps... And certainly not while you were in training, this was a fleet thing from my understanding. Damn, or am I thinking about the ACLS?

12 minutes ago, Sideburns said:

It's fairly easy to disable the mods using the built in mod manager, I have no issues running the T45 or A4c mods but I do have quite a stable system and DCS install.

yeah i'm aware, I use OVGME for skins... Tho I must say the mods have gotten better about not installing inside the DCS root directory of the install and going into the saved games folder instead (it used to not be like that)

Edited November 10, 2021 by Baz000

[Callsign JoNay]

@Victory205

-I do my best to fly within the G-limits and speed limits that I know of. 

 

-I used auto throttle because I thought it would produce a more scientific test result. I'd be happy to fly it again with boost if you want me to.

 

-I don't have time to AOA test missile weights today, and maybe not tomorrow, I have work and RL commitments for the next little while. Is there a specific configuration you want me to test?

[Victory205]

You've swerved into something, have a look at a couple of configurations that represent the spectrum of the load outs.

Should be obvious that I tend to favor "teach a man to fish" over "give a man a fish" approach.

The autothrottle limitation for new pilots seems to be a direct example of wise leaders ensuring that nuggets don't become dependent upon them. There were no such prohibitions that I recall on the F14, but few people used auto throttles beyond using them while downwind while they needed to divert attention to do something else. It was a different technique.

The aircraft in DCS will exhibit a long period phugoid in the landing config. It does it with wings fixed as well, more evident when they are forward than aft, which is a natural aircraft response- even an airliner on altitude hold exhibits it as evidenced by the speed cycling. This phenomenon can make the speed vary during these tests. Just get it as close as possible and average the mean.

Trim for most flying a sim means trimming while readjusting the stick location back to a neutral position. Trimming in an aircraft means reducing force by feel, while keeping the stick in the current position. It's a different technique to get to a common, desired result. The aircraft will constantly be experiencing slight displacements that require attention, even more so in the real world with natural turbulence, etc.

Edited November 10, 2021 by Victory205

[Callsign JoNay]

"You've swerved into something..."

Interesting. Ok I will take a look when able.

[sLYFa]

I havent tested all possible loadouts but the missile weights check out in both ME weight and on-speed crosschecks. E.g. a 1/4/2 loadout with 6lbs fuel shows 54klbs weight in the ME and gives about 138kts on-speed. The 1000lbs (1100 aktchually if you count the fairing) from the rails are missing here too though. 

So far, on-speed IAS is accurate for whatever weight is seen in the ME in my tests. Considering that rail weight is not accounted for in the ME weight, the FM does not "see" it as well. 

[Callsign JoNay]

7 hours ago, sLYFa said:

I havent tested all possible loadouts but the missile weights check out in both ME weight and on-speed crosschecks. E.g. a 1/4/2 loadout with 6lbs fuel shows 54klbs weight in the ME and gives about 138kts on-speed. The 1000lbs (1100 aktchually if you count the fairing) from the rails are missing here too though. 

So far, on-speed IAS is accurate for whatever weight is seen in the ME in my tests. Considering that rail weight is not accounted for in the ME weight, the FM does not "see" it as well. 

I concur. I got some time tonight and tested 1x4x3, 2x3x2, and 4x2x2. Speeds match the chart except for the 4x2x2 loadout which was about 4 kts slower than it should've been if the phoenix rails had proper weight to them. If Victory is trying to hint at something else wrong with the missile weights, I'm not seeing what it is.

[Baz000]

10 hours ago, Victory205 said:

Should be obvious that I tend to favor "teach a man to fish" over "give a man a fish" approach.

 

 

Reminds me of the "you can lead a horse to water but can't make it drink" idea.

I noticed the long term phugoid when flying around with just the gear and flaps as discussed a few days ago. Is there also a short duration phugoid oscillation that kinda gets coupled leading you into the long term too?

Also, would it make logical sense to think that with the SB and DLC engaged this may add more longitudinal stability and somewhat dampens the magnitude and/or duration of phugoid oscillation? I guess because of the added drag and slower approach speed.(so the wings produce a bit less lift, compared to without)

Considering that the SB is imparting a symmetrical force upon deployment (I'm assuming because of the clam shell design) the only other thing I could think of is that DLC engagement coupled also with the horizontal stab deflection is changing these wing lift forces, so there is probably more longitudinal stability and I would stab at a guess of less oscillation if configured that way... I mean, just thinking about the wing surfaces.

Providing power corrections are not wild and all over the place, which would certainly help to induce said oscillations.

I'm guessing in the fleet you guys had some rough idea gauge you would use when rolling out on downwind and completing the before landing checklist, some RPM or FF or FTIT value to roughly set each engine to in order to get configured and to on speed AOA at the proper altitude.

And the reason I say that is because it wouldn't make too much sense to trim to desired AOA while descending 200 ft and the engines are still at idle, because the moment you start applying power you're going to need to re-trim also, you take a risk in falling behind the power curve and the engines need time to spool up. And we don't want to blow through our target start altitude entering the groove. Always is said that if you have a good start entry, you're setting yourself up for the likelihood of a good trap on the boat. That is something constantly heard.

I was wondering something about the A model in particular, I know in the B model you're supposed to go to MIL power when the landing gear hits the deck in case of a bolter.

How did that go in the A? Is it one of those "it depends" things?

My best guess for the A they went full AB same as a cat shot?

Edited November 11, 2021 by Baz000

[RustBelt]

On 11/9/2021 at 10:48 PM, Baz000 said:

Is that per chance why they seldom if ever would carry six aim-54? Normally I've seen 2 or 4 aim-54 in the tunnel.

Six is similar to that shot of a C model Hornet with 10 aim-120.

 

 

Well that, and also the fact that they were EXPEN$IVE as all hell, and a Carrier only had so many of em on hand. Combine that with the fact that just putting an F-14 in the air with the threat that it had AIM-54's pointed your way did the job well enough even in "not technically a war" time. 

[sLYFa]

2 hours ago, Baz000 said:

best guess for the A they went full AB same as a cat shot?

 

There is no point in lighting the cans in the wires. Mil power provides more than enough thrust at max trap weights for a safe fly away. On the contrary, selecting AB can get you into huge trouble if one of the burners fails to light up, there is no AB asymmetry protection in the A. 

[Baz000]

42 minutes ago, sLYFa said:

There is no point in lighting the cans in the wires. Mil power provides more than enough thrust at max trap weights for a safe fly away. On the contrary, selecting AB can get you into huge trouble if one of the burners fails to light up, there is no AB asymmetry protection in the A. 

That was also along the lines of what I was thinking too, what if one fails to light etc... But if you are faced with plunging into the water and subsequently having the ship run over you vs a chance the AB fails to light or doesn't light symmetrically I mean which of the two would you pick? I'd take my chances with the AB.

The B has that asymmetry limiter because of the sudden massive yaw rate build up being produced by single engine failure or blow out being determined to be too great for the pilot to fix by kicking their boot in those critical phases of flight like takeoff or landing. They basically came up with, it is frankly highly impossible for the pilot to correct for this and to limit aircraft to MIL in certain critical phases.

The A is a bit of a different story tho, if the pilot can detect failure quickly enough they can use their boot to compensate the building of increasing magnitude of yaw rate, I guess the onset force compared to the B isn't as sudden or large in magnitude due to the thrust difference between the TF-30 and GE-110 engines.

Assuming you want the other engine still at MAX power, mind you. Which in certain circumstances you would...

In DCS, what I got into the habit of doing if experiencing a compressor stall and hitting the ground or the boat isn't an immediate problem... I bring both engines back on power to eliminate the thrust asymmetry and then slowly bring them up in power after the alarms have stopped and the small person with the sledgehammer in my air intake stops pounding it lol.

That has become kinda my knee-jerk reaction to it. I am worried all the time tho that I could induce a compressor stall on the good engine by doing that if already I have an issue with one engine it seems logical a issue could potentially develop with the other, right?

 

Edited November 11, 2021 by Baz000

[sLYFa]

53 minutes ago, Baz000 said:

But if you are faced with plunging into the water

Why would this be the case? A single TF-30 at MIL will give you enough thrust for a positive climb even at max trap weight. Max cat launch weight is a different story though, thats why they use burners on those in the A. The key to surviving a single engine failure during a bolter is adequate AoA (no more than 14), roll and yaw control, not excessive thrust. Adding AB doesnt help that.

Edited November 11, 2021 by sLYFa

[Victory205]

5 hours ago, Callsign JoNay said:

I concur. I got some time tonight and tested 1x4x3, 2x3x2, and 4x2x2. Speeds match the chart except for the 4x2x2 loadout which was about 4 kts slower than it should've been if the phoenix rails had proper weight to them. If Victory is trying to hint at something else wrong with the missile weights, I'm not seeing what it is.

Did anyone try flying with empty fuel tanks? Do the approach numbers still make sense?

I’ve been flying for weeks in the landing config in order to tune other parameters. While flying at a constant weight, often max trap, In certain load outs, I’m getting strange approach speeds that don’t make sense.  Adjusting fuel loads to put the aircraft at a constant weight results in varying speeds at 15 units AOA. It’s confirmed by other factors like stab angle and power required.

Been away for a few days and haven’t been able to evaluate what might be causing it.

[Bremspropeller]

20 pages in and still no diagram of Penny Benjamin.

 

You guys are letting me down.

[lunaticfringe]

3 hours ago, Bremspropeller said:

20 pages in and still no diagram of Penny Benjamin.

 

You guys are letting me down.

 

Diagram of Penny Benjamin:

1. Load up a copy of 'Career Opportunities'.

2. Fast forward to 1:08:35.

3. Go along with whatever she does. 

4. Involuntarily dig for quarters. 

[sLYFa]

4 hours ago, Victory205 said:

Did anyone try flying with empty fuel tanks? Do the approach numbers still make sense?

Putting tanks on makes things interesting...

I did three setups: Clean airframe, no gun ammo and: Full tanks, empty tanks, no tanks. Fuel levels adjusted to have 54000lbs (in ME)

Full tanks onspeed: 132kts

Empty tanks onspeed: 132kts

No tanks onspeed: 138kts

It seems like adding tanks removes weight from the FM rather than adding it. Looking at the numbers, about 3000-4000lbs go "missing" when putting on tanks, full or empty.

[Callsign JoNay]

4 hours ago, Victory205 said:

Did anyone try flying with empty fuel tanks? Do the approach numbers still make sense? 

I had empty fuel tanks, yes. I didn't notice anything out of the norm. I'll check again.

 

@Victory205 @sLYFa Are you guys testing A or B? I've only been testing B.

[Victory205]

Thanks sLYFa, that's looks like what I'm seeing. The configurations that I used obscured which stores contributed to the phenomenon, but based on your work and my notes, it looks like investigating tank dynamics is in order. Seems like the power required correlates also. 

2 minutes ago, Callsign JoNay said:

I had empty fuel tanks, yes. I didn't notice anything out of the norm. I'll check again.

 

@Victory205 @sLYFa Are you guys testing A or B? I've only been testing B.

Both, but I was looking at other aspects of the FM and noticed this as an adjunct of that testing. I will set aside time to look at it as soon as possible.

The tanks are going to be empty as a facet of carrier landing. What I initially surmised was that only fuel state might have been determining approach speed, not missiles, but it appears to be more complex than that.

[Victory205]

5 hours ago, Baz000 said:

That was also along the lines of what I was thinking too, what if one fails to light etc... But if you are faced with plunging into the water and subsequently having the ship run over you vs a chance the AB fails to light or doesn't light symmetrically I mean which of the two would you pick? I'd take my chances with the AB.

...I bring both engines back on power to eliminate the thrust asymmetry and then slowly bring them up in power after the alarms have stopped...

That has become kinda my knee-jerk reaction to it. I am worried all the time tho that I could induce a compressor stall on the good engine by doing that if already I have an issue with one engine it seems logical a issue could potentially develop with the other, right?

Mil power only in the wires, you can't make the ship go any faster. The problem, and there is a nice treatise in NATOPS about much of this, is the time for the TF30 burners to light. You can actually lose thrust for a moment as the cans open before light off. At landing weights, it isn't much of an issue as the max weight would be 54,000 lbs. 

Every CQ prior to a line period would involve a "day emergency" period (all other FCLP was almost exclusively performed at night). The emergency period involved SE passes with a throttle at idle at 14 units, no SB/DLC (combined failure), etc. The aircraft climbed fine single engine. We did SE wave offs, and were supposed to push up both engines before rotating on a SE FCLP pass, but on occasion one could try an SE touch and go and it wasn't an issue. F14 pilots were pretty aware and adept at using rudders.

The problem of course, would be if a pilot let a high descent rate condition develop, that's where burner is required, but if SE the aircraft should be at 14 units with a little margin. 

Losing an engine on takeoff in burner was a controllability issue more than a sink rate issue, as long as AOA was managed by proper rotation off the cat. Raising the landing gear closed the MCB's and gained thrust, which was in the procedure.

You may have noticed that the AOA shifts both index and tape to 17 units during test. Early on, to make the Navy approach speed specs, the aircraft was going to approach and land at 17 units, with the AOA reference shifting either when gear or full flaps was selected (I don't remember which). That would have killed a lot of ventral fins and burner cans to be sure, and it was scrapped with more WOD required and so forth. You may see the 17 unit reference in old docs from time to time.

Same thing with gross weights. The original max trap was 51.8, which was raised in the mid eighties, making life a lot easier. The max TO weight kept increasing, far beyond what I saw in order to accommodate the bombing mission primarily. Again, more WOD for launch and recovery was mandated to help offset the increases, but the energy addition and dissipation still increased on the AG and CAT.

[Katj]

Mil power only in the wires, you can't make the ship go any faster. The problem, and there is a nice treatise in NATOPS about much of this, is the time for the TF30 burners to light. You can actually lose thrust for a moment as the cans open before light off. At landing weights, it isn't much of an issue as the max weight would be 54,000 lbs. 
Every CQ prior to a line period would involve a "day emergency" period (all other FCLP was almost exclusively performed at night). The emergency period involved SE passes with a throttle at idle at 14 units, no SB/DLC (combined failure), etc. The aircraft climbed fine single engine. We did SE wave offs, and were supposed to push up both engines before rotating on a SE FCLP pass, but on occasion one could try an SE touch and go and it wasn't an issue. F14 pilots were pretty aware and adept at using rudders.
The problem of course, would be if a pilot let a high descent rate condition develop, that's where burner is required, but if SE the aircraft should be at 14 units with a little margin. 
Losing an engine on takeoff in burner was a controllability issue more than a sink rate issue, as long as AOA was managed by proper rotation off the cat. Raising the landing gear closed the MCB's and gained thrust, which was in the procedure.

You may have noticed that the AOA shifts both index and tape to 17 units during test. Early on, to make the Navy approach speed specs, the aircraft was going to approach and land at 17 units, with the AOA reference shifting either when gear or full flaps was selected (I don't remember which). That would have killed a lot of ventral fins and burner cans to be sure, and it was scrapped with more WOD required and so forth. You may see the 17 unit reference in old docs from time to time.
Same thing with gross weights. The original max trap was 51.8, which was raised in the mid eighties, making life a lot easier. The max TO weight kept increasing, far beyond what I saw in order to accommodate the bombing mission primarily. Again, more WOD for launch and recovery was mandated to help offset the increases, but the energy addition and dissipation still increased on the AG and CAT.

It has occurred to me that the extension of DLC (also in its "neutral" position) kills lift and thus increases approach speed. This should lower theoretical max trap weight accordingly.

Now, this may have been deemed necessary with the tf30 engines, but didn't it unnecessarily limit the max trap weight on the F110 equipped jets?

[Callsign JoNay]

Weird, I didn't get any of those empty fuel tank weight discrepancies int my tests last night.

 

 

I tried three missile configs, all with external tanks (empty), all tested with boost this time ), and I adjusted the fuel slider until I had a gross weight right around 54,000 as per the ME. All three tests produced an on speed of 138-139 kts, which is consistent with around 54K lbs in the natops chart. As I mentioned, the only problem I'm seeing is the lack of weight from the phoenix pylons. The 4x2x2 loadout should've weighed more like 56,000 lbs, but I got the same speed as if I was 54,000.

 

Miz attached.

 

AOA Weight Test.miz

[Victory205]

Very good, did you try removing the tanks only, leaving only the original missile load out, and noting if there is a speed difference at 15 units AOA?

Same process, but add fuel to put the gross at 54K again. Any change in speed?

[Callsign JoNay]

Not yet, but I'll try when I get some time.