F-14B acceleration correct?

[GGTharos]

Already discussed to death.  The limit is there for lifecycle hour preservation.

[IronMike]

We know for certain of a Tomcat that pulled 13G irl, and Okie himself once pulled 12G because the ground crew re-adjusted the center of his stick without telling him. We know of at least 2 other Tomcats that accidentally pulled around 11G. Needless to say that these planes had to spend a lot of time in maintenance. But saying "a real f14 could never go above 6G" is simply wrong. The limit that was imposed on pilots was 6.5 G, which has also been known to have been exceeded in dogfights to around 7.5G at times, by accounts of many RIOs and pilots. Their accounts are factual and can be corroborated, if you are willing to dig. But Okie, Victory, Paco, Meagan, Flash, Hey Joe, Billy, Ward, etc etc are all ppl who do not just make up stories to embellish themselves but to give truthful accounts. You can trust them, unlike Snorti who likes to spin sailor's yarn. That has nothing to do with muslce memory or simplification or reflex.

Edited June 17, 2021 by IronMike

[Mistang]

10 minutes ago, Spurts said:

That was not a structural limit, that was a Navy imposed operational limit.  The design limit was closer to 9G at 50,000lb and Grumman tested to 12G.  This is fairly common knowledge among those who have studied the Tomcat but would not be obvious to those who only know about published charts.  The F-14 has no G-Limiter at all.

I can't find any example of a tomcat going above 7g, and even that was for a few seconds. 
 

the 13g tomcat was probably trashed and that doesn't happen in dcs. 
 

the su 27 does not pull that many g, it's able to cobra easily and the tomcat can't. 

Edited June 17, 2021 by Mistang

[Harlikwin]

18 minutes ago, Spurts said:

That was not a structural limit, that was a Navy imposed operational limit.  The design limit was closer to 9G at 50,000lb and Grumman tested to 12G.  This is fairly common knowledge among those who have studied the Tomcat but would not be obvious to those who only know about published charts.  The F-14 has no G-Limiter at all.

 

Yup, the problem isn't really the HB modeling, its a consequence of DCS. You can't "feel" G's, so you have no real reference like a real pilot would. And then there are 0 consequences for pulling too many G's till you literally break the jet, and then who cares, you respawn. Its not limited to the 14, lots of stupid stuff gets done in DCS cuz there are no actual consequences for doing it unless you maybe you are playing on a tournament server and they disqual you if you do stupid stuff. 

 

Might be cool if HB put in a "limiter" option I.e. the pilot won't pull more than X G's. and have that be player settable as a compromise, perhaps not the most realistic tho.

Edited June 17, 2021 by Harlikwin

[Mistang]

1 minute ago, Harlikwin said:

 

Yup, the problem isn't really the HB modeling, its a consequence of DCS. You can't "feel" G's, so you have no real reference like a real pilot would. And then there are 0 consequences for pulling too many G's till you literally break the jet, and then who cares, you respawn. Its not limited to the 14, lots of stupid stuff gets done in DCS cuz there are no actual consequences for doing it unless you maybe you are playing on a tournament server and they disqual you if you do stupid stuff. 

Even so turning 7g  sustained just doesn't happen in real life for tomcat. 
 

the lifecycle limitation argument is unlikely because you're supposed to train in realistic conditions.

[GGTharos]

3 minutes ago, Mistang said:

Even so turning 7g  sustained just doesn't happen in real life for tomcat. 

 

Or any other aircraft.  AFAIK any excursions over 2g are likely very transient.  Let's say 3-5g for tac-turns happening regularly, but still pretty transiant.

 

Quote

the lifecycle limitation argument is unlikely because you're supposed to train in realistic conditions.

 

Sure, but what does this have to do with the design limit of 9g at 50000lbs?  Barring serious issues with the structure underperforming, the only reason for the limitation would be to preserve flight hours.

Edited June 17, 2021 by GGTharos

[Lt_Jaeger]

3 minutes ago, Mistang said:

 

the lifecycle limitation argument is unlikely because you're supposed to train in realistic conditions.

 Nope. No military in the world allows you to deliberately break there expensive stuff. There are so many limitations to extend the life cycle of airframe.... 

[Mistang]

1 minute ago, GGTharos said:

 

Or any other aircraft.  AFAIK any excursions over 2g are likely very transient.  Let's say 3-5g for tac-turns happening regularly, but still pretty transiant.

 

 

Sure, but what does this have to do with the design limit of 9g at 50000lbs?  Barring serious issues with the structure underperforming, the only reason for the limitation would be to preserve flight hours.

 

Who said it was 9g? The charts show 6.5. 
 

The tomcat g gauge only goes to ten so anything more isn't even verifiable. 
 

The test aircraft wasn't carrying anything most likely. So 9g clean is like 6g in terms of weight carrying Phoenix. Obviously a lighter aircraft will pull more g without breaking. 

[GGTharos]

6 minutes ago, Mistang said:

Who said it was 9g? The charts show 6.5. 
 

The tomcat g gauge only goes to ten so anything more isn't even verifiable. 
 

The test aircraft wasn't carrying anything most likely. So 9g clean is like 6g in terms of weight carrying Phoenix. Obviously a lighter aircraft will pull more g without breaking. 

 

Like I said, it's been discussed to death, we've even found charts of average g per hour use that shows (like most fighters, because the tomcat wasn't the only one of them) showing the F-14 beginning at 9g and dropping off along the same curve as the others.   Do you understand 'designed for 9g at 50000lbs'?   Barring special limitations noted in documentation, it's BAL (Basic Aircraft Limits) for any payload

So, if you can find that documentation HB will implement, and I'm sure they can point you to the relevant info for the airframe tests.

BTW, to the AIM-54 isn't all that heavy compared to the F-14 itself, the charts are for a 54000lbs aircraft which includes 2 phoenix IIRC.

Edited June 17, 2021 by GGTharos

[Mistang]

1 minute ago, GGTharos said:

 

Like I said, it's been discussed to death, we've even found charts of average g per hour use that shows (like most fighters, because the tomcat wasn't the only one of them) showing the F-14 beginning at 9g and dropping off along the same curve as the others.   Do you understand '9g at 50000lbs'?   Barring special limitations noted in documentation, it's BAL (Basic Aircraft Limits) for any payload

So, if you can find that documentation HB will implement.

I've never seen those charts, I've only seen the actual real world performance which was 6-7g with any kind of realistic load.

 

if the tomcat is completely stripped, in test situation to find the absolute maximum g not carrying radar or aux systems or anything I can see it being more. 

 

 

[GGTharos]

Just now, Mistang said:

I've never seen those charts, I've only seen the actual real world performance which was 6-7g with any kind of realistic load.

 

if the tomcat is completely stripped, in test situation to find the absolute maximum g not carrying radar or aux systems or anything I can see it being more. 

 

Ok, I'll be blunt:  You haven't brought anything new knowledge here.  Bring new knowledge and change will probably happen.

[Mistang]

1 minute ago, GGTharos said:

 

Ok, I'll be blunt:  You haven't brought anything new knowledge here.  Bring new knowledge and change will probably happen.

I'm not disagreeing with your data, I'm literally taking your argument to it's conclusion. 9g at 50k is like 7g at 55k. 
 

We're in agreement here I'm just doing math.
 

And as for the claim of no g limiter- it indirectly does because the variable geometry inlet will slow the plane at unstable conditions.

 

the A model has no limiter it simply compressor stalls.

[GGTharos]

It would be a bit over 8g by my computation but I'm sure I'm doing it wrong: (weight * g)/new_weight.  Factor in 1.3x safety margin and you get a lot more g capability out of the airframe than most people realize.

[Mistang]

3 minutes ago, GGTharos said:

It would be a bit over 8g by my computation but I'm sure I'm doing it wrong: (weight * g)/new_weight.  Factor in 1.3x safety margin and you get a lot more g capability out of the airframe than most people realize.

What about the hidden g limiter? Also the g gauge is complicated and unreliable it shouldn't be taken as evidence

 

it just seems odd a plane known for compressor stalls has such great turn rate. 

[GGTharos]

As far as I know compressor stalls were a feature of the TF-30 mostly under high AoA and maybe MIL->AB transients or just throttle movements that were too fast.

[Mistang]

8 minutes ago, GGTharos said:

As far as I know compressor stalls were a feature of the TF-30 mostly under high AoA and maybe MIL->AB transients or just throttle movements that were too fast.

The f110 did not fix compressor stalls. They simply limited the inlet geometry.

 

youve discussed this lots but never with an engineer.

[fat creason]

@Mistang If you look at the excess power charts it's very clear the F-14B can sustain turns way beyond the 6.5G "limit", with 8000 lbs of fuel and 8(!) missiles. It's hard to not call that a "realistic load" (I assume you really mean useful load here). It has more than 300 ft/sec (equivalent to 18000 ft/min climb energy!) of excess power while holding 6.5G at Mach 0.8 at sea level, meaning it has tons of extra power to climb, accelerate, or add more G above 6.5 while maintaining speed. It isn't until about 8000 ft @ Mach 0.85 that it can no longer sustain 6.5G. That excess power also increases dramatically as weight and drag from those stores and fuel is reduced. I'm not convinced you really know what you're talking about here.

 

 

54 minutes ago, Mistang said:

The f110 did not fix compressor stalls. They simply limited the inlet geometry.

 

youve discussed this lots but never with an engineer.

 

This is also false. The F110 is far more advanced over the TF30, and it has nothing to do with inlet geometry.

Edited June 17, 2021 by fat creason

[Mistang]

2 minutes ago, fat creason said:

@Mistang If you look at the excess power charts it's very clear the F-14B can sustain turns way beyond the 6.5G "limit", with 8000 lbs of fuel and 8(!) missiles. It's hard to not call that a "realistic load." It has more than 300 ft/sec (equivalent to 18000 ft/min climb energy!) of excess power while holding 6.5G at Mach 0.8 at sea level, meaning it has tons of extra power to climb, accelerate, or add more G above 6.5 while maintaining speed. It isn't until about 8000 ft @ Mach 0.85 that it can no longer sustain 6.5G. I'm not convinced you really know what you're talking about here.

 

This is also false. The F110 is far more advanced over the TF30, and it has nothing to do with inlet geomtery.

That graph seems to avoid giving g or turn rate.

 

the f110 has the same dry thrust, the entire difference is inlets.

 

every plane has hidden g limiters. I will leave the thread and let you disagree because I don't think you've adequately addressed this point.

[fat creason]

 

41 minutes ago, Mistang said:

That graph seems to avoid giving g or turn rate.

 

I stated in the post above that the chart I included was at 6.5G sustained. Alright, here's a chart at 5000 ft showing turn rate and G. Same loadout and weight as above (8000 lbs fuel, 8 missiles). At ~330 KIAS it can sustain 16 deg/sec at about 5.5-5.8G. However, it can sustain something like 7G near Mach 0.8, albeit at a slightly lower turn rate. Hope that adequately addresses this point.

 

 

 

41 minutes ago, Mistang said:

the f110 has the same dry thrust, the entire difference is inlets.

 

Again, this is false. Some basic research (like the first hit in a Google search) would reveal this. Additionally, there is no difference in the inlet geometry between the engine types, just a slightly different AICS ramp schedule to accommodate the different airflow requirements of the two engines.

 

The point of your posts in this thread is not clear to me. The only "hidden G limiter" in the Tomcat is the pilot's ability to not GLOC and/or structural failure of the airframe. It would be beneficial in the future for you to do some basic fact checking before you start typing. It's my expectation (and most others?) that you do your homework before you can have a meaningful discussion here. Otherwise you're just wasting everyone's time.

 

Edited June 17, 2021 by fat creason

[TLTeo]

> complains about sustained turn rate

> does not know what an excess power chart is

 

Peak DCS forum right there.

[GGTharos]

No, he's saying that the available g is too high, it's not really about turn rate.

[TLTeo]

His original title literally had "turn rate" in the title though. Besides, more available g (for a given airspeed) equals higher turn rate and all that...

[Spurts]

And when told of charts showing real world G excursions out to 9 the response of "well I haven't seen this chart" instead of "can you please help me find it?" shows a lot, also the "just doing the math" and doing it wrong.  This person came to be right, not to find facts.

[fat creason]

17 minutes ago, TLTeo said:

> complains about sustained turn rate

> does not know what an excess power chart is

 

Peak DCS forum right there.

 

6 minutes ago, Spurts said:

And when told of charts showing real world G excursions out to 9 the response of "well I haven't seen this chart" instead of "can you please help me find it?" shows a lot, also the "just doing the math" and doing it wrong.  This person came to be right, not to find facts.

 

Pretty much.

[maxsin72]

6 hours ago, Donut said:

So with the latest update I saw that ED...

• Added new pitot model implementation (Correct KIAS, KCAS, altitude calculation)

I was curious as to what this did so I ran my tests again and the results are interesting.

 

Whatever ED did seems to have affected the Tomcat as well.  The acceleration results I get now are different than my original ones.  The Tomcat is faster (at least what is indicated by TS speed in the info bar).  Most importantly though, I am not seeing the drag anomalies as indicated earlier in this topic.  All acceleration, speeds, and drag effects seem correct at this time.  
 

So... maybe everything was always correct and as @fat creason has stated, the FM isn't too far off as is.  It seems that just how speeds were indicated was wrong.

 

4 hours ago, IronMike said:

 

Correct - hence we do not really react to such tests as provided by you - even though we do appreciate it, read it out of interest, note it down, etc. But, as Creason said before, we have way better ways to test that, without even launching DCS. If we then get mixed into such results, we are thus in reality starting to discuss unknowns, partial or total, if you like. That was the point of pointing out: the indications that you guys have at hand, cannot be fully trusted. What can are the internal tests, scripts etc we use to verify and compare, which unfortunately you cannot have. Hence, unfortunately, you guys will always have to play catch up with us in this regard. And all we can offer sometimes is: trust us that we a) acknowledge what you guys post b) care deeply about fixing what in return really turns out as wrong and c) know what we are doing. This is of course incredibly unfair to those of you with such deep interest, it would be nice to take you "along the factory" one day, show you "see, here we do this here we do that", etc. to give you a tour. Unfortunately, due to the nature of our work being digital, and code not being able to be shared, this is not really possible. 

It is great that ED made these fixes, as it also perfectly demonstrates why we cannot really react to such tests. They do raise our eyebrows, they do make us investigate, but this also takes time. As drag is being adjusted anyway, all we could answer to your tests atm would have been "ok, thanks." Which means nothing at all. When we answer, we like to give you more than that of course (we did start to investigate your findings). In this case of course you found your own answer in the meantime, which is lucky but ofc is rarely the case in this situation of what devs can see vs what players can see.

It is a good demonstration of how scewed perception can be from reality sometimes (and none of it is your fault really). And while it pains me that you as users are put at a disatvantage because of it, when trying to verify these things, I can assure you at the same time that when it does correlate or point towards things we can verify on our side, we do address it. Which is the goal of this entire exercise. You guys noticed the performance being off and you were right in principle. We followed suit by going into a lengthy process of fixing it, which, as we established by now, really takes a lot of time, due to the ripple effect everything has in terms FM. It is a painful procedure, and I can only bow my head to Creason and Victory for putting so much time into it. Why am I saying this: simply, because we have to be aware that threads like these - after we said "we are on it", really serve more to help you better understand, than us to fix stuff (which ofc is fine and we are happy to do that). Now, I am not saying that there is no useful feedback in this thread for us, there certainly is - and even if it wasn't, we would still appreciate your feedback, your tests, your time and your passion you devote to the F-14. We really do. And most certainly we also do learn new things from the exchange with you guys, always. But sometimes it is also important to put things into perspective. The outlook being: we're on it, and it will get fixed. You have to understand guys, and I think most of you do: we really, really want you to be 100% happy with the Tomcat.

Thank you all so much again for your great feedback, for your very kind patience and for the avid discussions. Please keep bringing it on!

 

It's still impossible to go past mach 2.2, tried several times with 0 winds and 20°C, instant mission free flight Nevada after jettison fuel tanks and shot sidewinders, so with clean configuration. Sooner or later i would be happy to see the Cat at 2.4 mach.

Edited June 17, 2021 by maxsin72