Is this right for level flight?

[imacken]

I don't ever fly the F-14,  but I thought I'd give it a quick try tonight, and apart from not being able to get the auto-pilot working, level flight seemed odd.

Do the attachments look right?  I mean when the the velocity vector is level, the vertical velocity is showing quite a big negative value and level flight shows the velocity vector higher than I would expect.

Sorry about the basic question!

[iantron]

It is correct. That wing is not a velocity vector, just wings on the pitch ladder.

Switch to landing mode and you'll see the velocity vector for comparison.

[imacken]

Ah ok, thanks. What is the point of those wings then?

[iantron]

It's the bank and pitch reference on your pitch ladder.

[imacken]

Sorry to be pedantic, but how can it be a pitch reference on the ladder when it’s not at zero in level flight?

[near_blind]

 

https://pilotclimb.com/flight-path-vector-fpv/

[Dragon1-1]

It's important to understand that the F-14 HUD doesn't work like in the newer jets. You don't have a "real" pitch ladder, just an ADI that's in front of your face. It doesn't correspond to horizon and, crucially, the velocity vector (in HUD modes that provide it) is independent of it. For example, putting the VV on the 10 degree ladder doesn't actually put you into a 10 degree climb, and the zero pitch line won't be on the horizon. It's weird, but that's just the way it is. The modern HUD was yet to come at the time the F-14 was designed.

[Rokkett]

However, you can zero the wings over the horizon line of the pitch ladder (using the HUD trim knob) and have the whole thing work in much the same way as more modern HUDs.

[GrEaSeLiTeNiN]

Coming from modern jets, the F14 needs a bit of adjustment. I was getting confused too. The way I understand it, the ladder's centre line moves with the aircraft's pitching. It's not a horizon line. Where the small 'wings' (referred to as "aircraft reticle" in Chuck's guide) point at any time on the ladder is where the aircraft's longitudinal axis/nose is pointing in relation to horizontal. So if the wings are at say -30deg on the ladder, you are pitching 30deg down in relation to horizontal. If at +90deg, you are nose up vertical. When the wings coincide with the ladder's centre line, you are horizontal (not with the horizon, just level). Nothing to do with the VV or FPM. You can test this in external view.

Example of autopilot alt level flight (no vertical velocity) for current config (FPM at 5deg, 'wings' above centre line, HUD in landing mode).

Edited February 27, 2022 by GrEaSeLiTeNiN

[Lt_Jaeger]

All pretty easy....as soon as you are leveled out, referencing the instruments rather than the HUD, you could use the two knobs HUD Trim and VDI Trim to trim out the respective indications for THAT regime of flight.

You will quickly learn not to reference the HUD for indication, but the instruments. As much as I recall it was stated that the HUD itself is not rated for instrument flight, the jet himself is though.  That said, VDI is some magnitude more reliable for the indication of the "flight status", so get used to use that thing and disregard the HUD

 

 

[imacken]

Thanks a lot for all your useful input here, guys. I'm glad I wasn't going mad!  I'm going to study this in more detail now.

[Nealius]

I've found it easier to think of that T symbol as equivalent to the Witch's Hat in the Harrier. The only times I really use it are when coordinating turns against some reference in the distance (can't see the yaw string well and the inclinometer is unreliable) and when getting on-speed AoA for landing. For on-speed AoA the E bracket should be centered on the T.

[9thHunt]

the pitch ladder on the tomcat is offset 5° from the horizon, IIRC it is for better visibility

[eatthis]

On 2/26/2022 at 11:55 PM, imacken said:

Sorry to be pedantic, but how can it be a pitch reference on the ladder when it’s not at zero in level flight?

it is level if you set the pitch ladder using the knob, it isnt the most reliable lol i use the vsi to check level. also the horizon should be around 1/3rd of the way down from the top of the front glass when level and that can be misleading, take a little time to get used to

[cw4ogden]

On 2/26/2022 at 3:08 PM, imacken said:

I mean when the the velocity vector is level, the vertical velocity is showing quite a big negative value and level flight shows the velocity vector higher than I would expect.

Select HUD Landing mode and you'll have a velocity vector on the hud which will be on the horizon when in level flight.

[Lurker]

The hud in the Tomcat was a fairly new fangled thing, and was never meant to be used as a primary instrument. There were reasons for the pitch ladder being offset to the horizon, the primary being, there was no easy way to calibrate it at the time. Once you get used to it you don't really notice it anymore and I for one prefer the lean and minimalistic HUD of the F14 compared to most other fighters out there. If I need more info, I look at the relevant instrument in the cockpit. 

[Nealius]

15 hours ago, Lurker said:

The hud in the Tomcat was a fairly new fangled thing

I've always been confused by this statement, as it is always cited in reference to the Tomcat's poor HUD functionality. The A-7 had a near-modern HUD and it first flew 5 years before the Tomcat, so the concept of a fully instrumentated HUD wasn't that new. 

[some1]

The first A7s did not have such a fancy HUD like we know from the upgraded D and E models. 

The F14 suffered from protracted development and budget cuts. The F14A, instead of being inertim configuration of the first few dozen units, became the main variant for the whole cold war and beyond. 

Also HUD is not a super high priority if the aircraft primary role is lobing BVR missiles.

[Nealius]

Budget cuts and protracted development seem to make the most logical sense. Even the A-7D was 2~3 years before the Tomcat.

[DD_Fenrir]

Many of the F-14 vs A-7 HUD discrepancy questions answered here:

 

[some1]

6 hours ago, Nealius said:

Even the A-7D was 2~3 years before the Tomcat.

In terms of aircraft design that's basically concurrent development. Especially taking into account different manufacturers, different military communities and even different branches. 

 

[Dragon1-1]

Also, the HUD on the A-7D was exceptional for its time, I think it was the same unit as the one used in A model Vipers. Most other aircraft of the era had HUDs more like the F-14.