F-14B acceleration correct?

[Spurts]

1 minute ago, maxsin72 said:

 

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.

 

Are you in a B or an A?  IIRC the A has superior thrust above 1.6M at altitude and all high speed (M2+) runs in the real plane were in As.  trying to find info I heard about Bs now to verify

[maxsin72]

15 minutes ago, Spurts said:

Are you in a B or an A?  IIRC the A has superior thrust above 1.6M at altitude and all high speed (M2+) runs in the real plane were in As.  trying to find info I heard about Bs now to verify

B Tomcat, anyway both A and B on the charts are mach 2.4 capable.

 

[captain_dalan]

2 hours ago, GGTharos said:

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

Actually he both didn't recognize the relation between Excess power at mach/alt and sustained turn rate AND incorrectly associated compressor stalls with g limits ON top of allowed g due to over stress. The future is indeed not bright with engineers like this

[fat creason]

Keep in mind that right-most line is with 8 missiles and 8000 lbs of gas, so clean max speed will be a little higher. Also note that neither aircraft comes close to 2.4 according to flight test. Kinda skeptical that removing the missiles would result in a 0.25 mach speed increase ("2.4" clean vs 2.15 with 4x4 loadout), that's a lot of extra drag at those speeds.

Edited June 17, 2021 by fat creason

[maxsin72]

5 minutes ago, fat creason said:

Ok, Grumman validation test for F14A at Mach 2.41, data sheets and DoD Mach 2.34 requirement are only tails for childrens.

[fat creason]

9 minutes ago, maxsin72 said:

Ok, Grumman validation test for F14A at Mach 2.41, data sheets and DoD Mach 2.34 requirement are only tails for childrens.

 

Ok, if you have the doc or a link post it here. Also the performance manual is a tale for children? That's an interesting take. 

[GGTharos]

The performance charts tend to have an acceleration cut-off.

[fat creason]

7 minutes ago, GGTharos said:

The performance charts tend to have an acceleration cut-off.

 

This is true, but the charts above are not from the acceleration data. These numbers are much higher than where the acceleration charts stop.

Edited June 17, 2021 by fat creason

[maxsin72]

44 minutes ago, fat creason said:

 

Ok, if you have the doc or a link post it here. Also the performance manual is a tale for children? That's an interesting take. 

Do the name of Mike Ciminera tell you something? I really hope you know very well who he is https://youtu.be/SsUCixAeZ0A?t=785

Please look at the video at minute 13:06 when he talk about mach 2.4.

I also remember you that if you look at the manual F14 is not able to go past 6.5G but obviously this is not true

[Frosty2124]

17 minutes ago, maxsin72 said:

Do the name of Mike Ciminera tell you something? I really hope you know very well who he is https://youtu.be/SsUCixAeZ0A?t=785

Please look at the video at minute 13:06 when he talk about mach 2.4.

I also remember you that if you look at the manual F14 is not able to go past 6.5G but obviously this is not true

Did we not just get out of a conversation where we were discussing providing evidence before smashing ones face upon the keyboard?

 

here we are yet again, get the evidence, actual factual evidence as in pictures, video or charts.....come on guy, you're better than this. 

[fat creason]

A slide about the Navy's requirements for the VFX is not hard proof that it was achieved in reality.

Best I could find was this, on a random internet forum:
 

Quote

 

The F-14A was listed with top speed of 2.34, but actually made 2.41 during flight test (the RIO was tweaking the ramps via special control box in the test article).

 

 

If this is to be believed, it sounds like 2.4+ may have been achieved on a development test flight by manipulating the AICS ramps manually. This test article was not reflective of production aircraft. I see at lot of 2.34 numbers being tossed around, again, on internet forums with no hard evidence.

Edited June 17, 2021 by fat creason

[Mistang]

Yes, good graph, it simply gives the 6.5 number.

 

it would be strange for an engineer to care about lifecycle because that should be set operationally by the navy. It's like a car designer telling you how to drive. It doesn't work that way, you decide what load and speed to carry your car.

[IronMike]

33 minutes ago, maxsin72 said:

Do the name of Mike Ciminera tell you something? I really hope you know very well who he is https://youtu.be/SsUCixAeZ0A?t=785

Please look at the video at minute 13:06 when he talk about mach 2.4.

I also remember you that if you look at the manual F14 is not able to go past 6.5G but obviously this is not true

 

Hey Maxsin, yes we of course know who Mike Ciminera was, and we all know the video. But - sorry that there is always a but - this is not unsimilar to the talk we once had about Snorti. Now Ciminera and Snorti are nothing of the like, even if he may have been buddies with his dad, most likely, hehe - but the point is: the mach 2.4 is something that was a) wanted and b) achieved once only (maybe twice, not that I know of), under very special conditions.

Having someone in the backseat manually temper with the ramps to make it go past what the schedule would allow, is not really worth modeling. What for? So you can once fly all the way to M2.41 and then have to immediately eject, because you ran out of fuel? And mind you - only if we modeled the ability for the RIO to pull some buses or the likes, and then also only if you actually found a RIO who would do it properly.

At M 2.34 even, you will be just empty, unless you cheat and dive ofc. Rarely will it matter to you, to be beyond M1.6.

These are - like Snorts example with the flaps - all edge cases, exceptions, not under normal circumstances and also irrelevant to accurate modeling. How much G it can pull is very different, because that can happy anywhere, any time. Going M 2.41, I can assure you, is an exercise you would do once. And again, only if we gave you the tools, through a lot of investment from our side for little return.

What is important, is that it meets the performance under normal, realistic circumstances, and not edge cases or special circumstances. This is why it will take you to 2.34 ish. Since everything else is modeled correctly, I bet you, if we disabled the ramp stuff or have it set correctly, we could prolly reach 2.4 (when done with the performance tweaks). But again, you couldnt even do it on your own. And we certainly wouldn't model that for Jester. It does not serve you anything. It is not like you can fly around at M 2.4 for more than couple seconds after you reached it anyway. And it would likely take you 10-20 min to get there in the first place.

These numbers give ballparks, and again are here mentioned to an audience who doesnt see a difference between M2.34 and M 2.41. That is not of any interest to them. Furthermore, tests are sometimes done to prove a point. After the point was proven, the M was limited to 1.8x (Victory mentioned the exact number in this thread iirc, you can check). There is a reason for it.

We need to make sure it reaches 2.34 ish under normal circumstances. Not 2.41 in some rigged situation. And what we do make sure, is that the performance is such so that if we did rig the situation, you could reach 2.41 theoretically. Because that is what most of these tests are: theoretic. And so, theoretically, you could reach 2.41 with ours as well. But there is no need to provide such circumstances, even if you would like to have it. Even if you really, really wished for it, trust me, you would get little to nothing out of it.

Edited June 17, 2021 by IronMike

[GGTharos]

3 minutes ago, Mistang said:

Yes, good graph, it simply gives the 6.5 number.

 

it would be strange for an engineer to care about lifecycle because that should be set operationally by the navy. It's like a car designer telling you how to drive. It doesn't work that way, you decide what load and speed to carry your car.

 

It is set by the USN.  The F-15A was a 7.33g aircraft until the OWS was installed.  Did the engineer suddenly wake up and decide that he forgot to put in the correct g-limit?

Edited June 17, 2021 by GGTharos

[Frosty2124]

Just now, Mistang said:

Yes, good graph, it simply gives the 6.5 number.

 

it would be strange for an engineer to care about lifecycle because that should be set operationally by the navy. It's like a car designer telling you how to drive. It doesn't work that way, you decide what load and speed to carry your car.

bruh really.... we design aircraft to meet the requirements of the customer. the customer wants 20 years of service, we design, build, and develop maintenance schedules to provide that life cycle. the customer then takes that gen and tightens it down if they need more life out the jet. or if they wanna fly it harder they need to collect and provide EVIDENCE (shocking i know) to get sign off from the design auth before sign off from the relevant operating authority

 

Sincerely

 

Former Typhoon Part 145 engineer

[Mistang]

4 minutes ago, GGTharos said:

 

It is set by the USN.  The F-15A was a 7.33g aircraft until the OWS was installed.

Here's a similar thing from the tomcat Wikipedia.

 

 Two triangular shaped retractable surfaces, called glove vanes, were originally mounted in the forward part of the wing glove, and could be automatically extended by the flight control system at high Mach numbers. They were used to generate additional lift (force) ahead of the aircraft's center of gravity, thus helping to compensate for mach tuck at supersonic speeds. Automatically deployed at above Mach 1.4, they allowed the F-14 to pull 7.5 g at Mach 2 and could be manually extended with wings swept full aft. They were later disabled, however, owing to their additional weight and complexity

 

so it straight up implies a g limiter of 7.5 which was later reduced.

 

and yes it's different with modern aircraft that have known, hard coded g limits (the tomcat did too it was just a aerodynamic one). 

Edited June 17, 2021 by Mistang

[Frosty2124]

4 minutes ago, Mistang said:

Here's a similar thing from the tomcat Wikipedia.

 

 Two triangular shaped retractable surfaces, called glove vanes, were originally mounted in the forward part of the wing glove, and could be automatically extended by the flight control system at high Mach numbers. They were used to generate additional lift (force) ahead of the aircraft's center of gravity, thus helping to compensate for mach tuck at supersonic speeds. Automatically deployed at above Mach 1.4, they allowed the F-14 to pull 7.5 g at Mach 2 and could be manually extended with wings swept full aft. They were later disabled, however, owing to their additional weight and complexity

 

so it straight up implies a g limiter of 7.5 which was later reduced.

no it doesn't

[fat creason]

There is no G limiter on the F-14. Not sure how many times it needs to be repeated. It can pull much more than 6.5 or 7.5G if you ask it to, that's extremely obvious. In most situations at that load factor, you're going to be losing speed (negative excess power) and it cannot be sustained.

Edited June 17, 2021 by fat creason

[Mistang]

Just now, fat creason said:

There is no G limiter on the F-14. Not sure how many times it needs to be repeated. It can pull much more than 6.5 or 7.5G if you ask it to, that's extremely obvious. In most situations at that load factor, you're going to be losing speed (negative excess power) and it cannot be sustained.

 

I dunno, Wikipedia seems to contradict that. We have only two instances of cats ever going over 9g and both are probably A models which would compressor stall.

[Frosty2124]

2 minutes ago, Mistang said:

I dunno, Wikipedia seems to contradict that. We have only two instances of cats ever going over 9g and both are probably A models which would compressor stall.

you're misktaing g-limiits with g-limiters

 

G-LIMITS are how much a jet can pull before it dies or what the navy they want the pilots to pull

 

G-LIMITERS are physical restraint systems within the jet that prevent the aircraft from going over a certain G

Edited June 17, 2021 by Frosty2124

[fat creason]

I need to tap out of this discussion, I've run out of ways to explain this. Hopefully someone else can explain things.

[Mistang]

1 minute ago, Frosty2124 said:

you're misktaing g-limiits with g-limiters

 

G-LIMITS are how much a jet can pull before it dies or what the navy they want the pilots to pull

 

G-LIMITERS are physical restraint systems within the jet that prevent the aircraft from going over a certain G

 

Yes I mean hidden limiters like glove vanes.

[TLTeo]

LOL Wikipedia. Wow.

[Frosty2124]

1 minute ago, Mistang said:

Yes I mean hidden limiters like glove vanes.

the glove vanes aren't g-limiting devices, they are lift augmentation devices

[Mistang]

Just now, Frosty2124 said:

the glove vanes aren't g-limiting devices, they are lift augmentation devices

Wikipedia implies they also limited g.

 

but we're attacking sources at this point.

 

my only question is did the tomcat ever hit 8g in real life? Was okie flying an A model when he made that claim and did he think it would matter?