How to hit Mach 2.4?

[Hawkeye91]

According to this new video, the F14s flew at Mach 2.4 to intercept the SU22s. Now, This is a struggle to this this speed in DCS. Details missing from this are what altitude did the start at, what was there fuel state, stores, ect? They had at least 2 sidewinders each and I'm guessing they had drop tanks because I'm fairly certain they navy would ALWAYS equip drop tanks on carrier launches because you always want extra gas over the water. So my question is, how where they able to hit Mach 2.4 to intercept these guys? 

 

[DD_Fenrir]

Your first mistake is assuming that a YouTube video is a faultless source of information.

I have watched many of these Operations Rooms videos and - while entertaining - they all have errors; the Desert Storm, Operation Jericho and this one have various, some small, some not so.

 

Edited June 13, 2022 by DD_Fenrir

[Gun Jam]

Im curious about this as well.The internet agrees that mach 2.4ish is the top speed for the A model. I dont think ive ever seen anything above mach 1.6 (but I usually only fly the B)

Can any SMEs actually provide the realistic top speed and whats required to reach that Mach value? Then there is confusion about mach vs knots to measure top speed (at least in my head)

 

[DD_Fenrir]

Top speeds are usually gained at a specific altitude (usually higher) and a particular loadout.

A combat loaded Tomcat won’t get much above Mach 1 below 20,000ft. Even above that height you need a lot of space, time and fuel to get to 1.6, but the less ordnance you have hanging off the plane the better.

For big Mach numbers you need to be Angels 30 and up. Phoenix are too draggy so a sparrow load out will better assist reaching the Mach 2 region of the flight envelope.

[WarthogOsl]

I've always heard the top speed listed as Mach 2.34...since forever.  It actually seems pretty rare for Tomcat pilots to have ever even reached Mach 2 in their careers (based on some anecdotal answers on the F-14 Tomcast podcast).

[DD_Fenrir]

That's true for all aircraft. As an alternative let's look at the Spitfire LF.IX: it had, in one test, achieved a top level speed of 411mph. However, there are specific parameters:

1. Clean airframe, no stores
2. You had to be using War Emergency Power of 18lb boost (and were limited to 5 minutes at this power setting)
3. You had to be at 21,000ft (any higher and the horsepower drops and decays airspeed, any lower and the air density increases, increasing drag and again decaying airspeed)

Add to this the fact that the 411mph figure is a TAS figure and you find that in cockpit you're Air Speed Indicator would register only~300mph. So, unless you are diving, you'll never as a Spitfire pilot see 411mph straight and level on the ASI.

A similar effect is true for Mach number. On a standard atmosphere day:

Mach 2.34 at sea level is ~1540 Knots

Mach 2.34 at 20,000ft is ~1240 Knots

Mach 2.34 at 30,000ft is ~1100 Knots

Mach 2.34 at 40,000ft is ~940 Knots

So where do you think you'll be more likely to see Mach 2.34?

 

Edited June 14, 2022 by DD_Fenrir

[CarbonFox]

Atleast in-game I've noticed the F-14 (both A and B) can run upto Mach 1.2 quite easily and then seems to hit some kind of wall where it takes quite abit of time to reach Mach 1.6.

[Uxi]

I got a bit past Mach 2.1 in the B though had to drop my bags to get past the hump at 1.8 ish. Hit bingo and did an idle glide back to the carrier to trap.

[QuiGon]

5 hours ago, Uxi said:

I got a bit past Mach 2.1 in the B though had to drop my bags to get past the hump at 1.8 ish. Hit bingo and did an idle glide back to the carrier to trap.

Should get even faster if you remove the pylons for less drag and fly higher.

[Spurts]

I got an A with six Sparrows and two Sidewinders up to 1.86M at 45,000ft doing an intercept profile test.  I was accelerating and climbing from 1.4M at 30,000ft (holding roughly 550-560KIAS).  Spent almost 5 minutes above M 1.7 before hitting my waypoint 150nm from the boat.  Full mil power return flight at 34,000ft to trap with 3,000lb remaining.  Roughly 11 minutes in full AB.

[WelshZeCorgi]

I always wondered, is Mach 2.4 the fastest the plane has EVER flew? Or is it that the number in level flight? Cause you can always point the nose down with after burner from 42,000 feet and probably reach 2.4 before hitting the much denser air. But if in level flight, the 14 must be capable of going faster than Mach 2.4, right? point the nose down and continue using gravity to speed up the aircraft. 

[Spurts]

Unconfirmed accounts of pilots claiming to hit 2.7 in the A model.  Once must assume a light and completely clean jet, and it probably would not be a stretch to assume it was a cold day and that the engines of that particular bird ran a bit hot.  So IF that account is true it does NOT represent what we should expect from our DCS A model, especially a loaded one.

[DD_Fenrir]

The Vne is determined by structural limitations and, above supersonic speeds, airframe heating limitations. 

Go above Vne and you can start to expect deformation, failure or even outright detachment of panels.

Windshields and canopies on the 4th gen types tends to be the limiting factor. It is probably likely that the Tomcats windshield was the defining limiter. But like structural g limits there was a safety margin built in to allow for a little… over exuberance. Hence making it to 2.7.

IIRC I read that article detailing the 2.7 run; didn’t they lose a panel or two or am I mis-remembering?

 

[WelshZeCorgi]

https://www.19fortyfive.com/2021/11/how-an-f-14-tomcat-hit-a-record-mach-2-5-top-speed/

 

Found this article, not sure if it will put a bow on this thing. 

“My squadron had one jet that was a real ‘hotrod.’ It always flew great, trimmed up perfectly, and out-accelerated and was faster than all the other jets in the squadron. Even the AWG-9 radar/weapons system worked better than the other jets. Everybody loved flying it,” he wrote.

“One of my most memorable flights was taking that one out on a post-maintenance check flight. When flying from our home base on land we would do these and other training flights in designated ‘restricted’ military training areas that were a hundred miles or more out over the Atlantic Ocean east of the Virginia/North Carolina coast. The PMCF checklist called for a supersonic dash up to 1.2 Mach as one of the checks, so this being the squadron hotrod, of course we decided to see what she’d do (despite the imposed NATOPS speed limit of 1.88 Mach),” he added.

“So we climbed to around 40K ft, pointed her east away from the coast, the pilot pushed the throttles into full burner, and we let her rip (note: the jet was in a ‘slick’ configuration, no drop tanks or missile rails). That jet accelerated like it was blasted out of a cannon. In maybe fifty seconds we went from about four hundred knots and reached the advertised top speed of Mach 2.34, and the jet was still accelerating. I’m sure she would’ve gone past 2.5 Mach if we’d let her, but backed off at that point because we were getting close to ‘bingo’ fuel state,” he continued.

Edited June 16, 2022 by WelshZeCorgi

[WelshZeCorgi]

If true, it does seem like the 14 we got in DCS does not have a similar flight model, cause going to mach 2+ in less than a minute from 400 knots @ 40,000 ft is not possible in DCS. 

[bies]

Mach=1.4, not 2.4, it's some mistake in the video.

To go Mach 2.4 Tomcat would need to fly with max 4 Sparrows in semi-recessed low drag fuselage pylons only, no Sidewinders and for sure no Phoenixes. It would need to fly straight and high at least 37,000-40,000ft, accelerating for a long time. In tactical situation like the one in the video when they needed to have their options open and be able to outmaneuver the enemy flying at Mach 2 would be a big mistake.

[Spurts]

1 hour ago, WelshZeCorgi said:

If true, it does seem like the 14 we got in DCS does not have a similar flight model, cause going to mach 2+ in less than a minute from 400 knots @ 40,000 ft is not possible in DCS. 

Why should the DCS flight model be representative of the squadron hot rod?  There are no charts for that.  That is also a non-scientific statement about both the speeds and times.  also, 400kts on the dial at 40,000ft is already what? 1.2M?

 

2 hours ago, DD_Fenrir said:

IIRC I read that article detailing the 2.7 run; didn’t they lose a panel or two or am I mis-remembering?

The panel losing story I recall was from low level (TARPS?) runs over Libya(?) where they lifted the NATOPS low level limit 

[WelshZeCorgi]

Well, has anyone gotten the DCS 14 to M2.34, clean, level, at any altitude without first running out of fuel?

Edited June 16, 2022 by WelshZeCorgi

[Spurts]

Sure, when the A was first released and super buggy I got it to Mach 3.2.  Seriously though, I have not bothered trying taking the shoulder pylons off to get a properly clean jet.

[Uxi]

7 hours ago, QuiGon said:

Should get even faster if you remove the pylons for less drag and fly higher.

I could have stayed with it a bit longer with the cans lit,  too, but wanted to trap instead of running out of fuel. 

[Golo]

I got A to just over M2.2 at shallow descent from about 45k to 38k. AIM-7s at stations 4, 5 otherwise clean. Im sure it would go faster but I was getting to bingo as I was passing 38k. That was few moths ago, I might just try again now. 

[DD_Fenrir]

Don’t forget that early A’s had TF30’s that had significantly more oomph than those in later years; they were gradually de-rated, probably to increase service life and help stop the jets eating themselves.

The 2.34 max would have come from early testing before the de-rating; it’s therefore unsurprising that you cannot hit that number in the 135 which is representative of those later models with less thrust.

Edited June 16, 2022 by DD_Fenrir

[Hawkeye91]

8 minutes ago, DD_Fenrir said:

Don’t forget that early A’s had TF30’s that had significantly more oomph than those in later years; they were gradually de-rated, probably to increase service life and help stop the jets eating themselves.

The 2.34 max would have come from early testing before the de-rating; it’s therefore unsurprising that you cannot hit that number in the 135 which is representative of those later models with less thrust.

 

Interesting. I did not know the TF30s were derated in our version in DCS. Do you know by how much exactly?

[DD_Fenrir]

Not off the top of my head: Bio references it in the F-14 Tomcast episode dedicated to the F-14a first fleet deployment.

 

[Panny]

13 hours ago, WelshZeCorgi said:

Well, has anyone gotten the DCS 14 to M2.34, clean, level, at any altitude without first running out of fuel?

 

yup, think fastest I achieved was M2.42. Launched with bags, tanked, got to altitude, accelerated to around M1.7 by the time bags were empty, jettisoned them and continued to push aircraft while around 36k feet