Q's about manual wing sweep + combat radius

[Pocket Sized]

From what I've read the tomcat will rely mostly on automatic wing sweep, but it can be overidden by opening a cover over the sweep control.

 

So, will we be able to gain an advantage by manually sweeping the wings in certain conditions? I.e. sweeping them forward when doing CAS for tighter turning and better L/D ratio or sweeping them aft in preparation for a "bug out" maneuver, or is the automatic system fast enough that it wouldn't make a noticeable difference?

 

What are the limits with the wings swept vs unswept involving AoA, G load, and Mach number? I'd imagine going supersonic with the wings forward would be a VERY bad idea :D

 

On an unrelated note, how big are the tomcat's legs in comparison to other air superiority fighters? It's a very big plane but has similar TWR to an F-15/18, plus the drop tanks look rather small :( is the internal fuel enough that it doesn't rely on bags as much as the F-15/16/18 or is it doomed to hug a tanker for long missions?

[Revelation]

Here's a story that you might find interesting...

 

F-14 Story

[lunaticfringe]

1. You cannot "undersweep" the program. Progression in manual forward will stop when the wings reach the program minimum. IE, you cannot force 20 degrees when the programmed minimum is 40. The sweep override cover is only utilized in emergencies, and won't override the minimum. The reason it's used in emergencies is because it's marked with relative positions, whereas the thumb switch is merely "FWD" and "AFT", and requires usage of the ACM panel gauge to *confirm* required programming, rather than *direct* the CADC to put the wings in the required setting.

 

2. There are a number of tactical reasons beyond merely falsifying an energy state intro to a fight for which sweep may be set over normal parameters. Remember- with increased sweep comes the increased drag of an increased delta profile. If you're sitting slightly hot to make your first turn, the rapid loss rate will put you at your intended speed faster; you simply need to remember to go Auto after the turn, and the sweep mechanism will program forward.

 

While it sounds like a mere offshoot of the "fast" look, in practice it didn't work that way; in fact, TOPGUN issued a number of Journal articles regarding the technique over the years.

 

3. The original mach sweep program of the F-14 was set for CL Max, with sweep not initiating until M 0.75; after review by Navy, the determination was that for type longevity- specifically of the wings as they showed substantial flex that made some non-aero admirals consider, that the program would be reset for specific excess power.

 

4. With regards to range, the F-14 in both engine configurations had substantially longer legs than the Hornet, and a reasonable increase over the F-15. The external bags carried an additional 3600 lbs of gas, or roughly 20% more. In a wartime CAP orientation, a two ship could top up coming off the boat, run out 300 miles, loiter two hours well hung, and head back.

Edited October 12, 2016 by lunaticfringe

[Hummingbird]

 

3. The original mach sweep program of the F-14 was set for CL Max, with sweep not initiating until M 0.75; after review by Navy, the determination was that for type longevity- specifically of the wings as they showed substantial flex that made some non-aero admirals consider, that the program would be reset for specific excess power.

 

Yeah according to the manual the new sweep program had the wings starting to sweep already at M 0.44, albeit not by much only changing a mere 1.5 deg until around M 0.62 where the sweep starts picking up linearly until max sweep at ~M 0.95.

[majapahit]

.. the new sweep program had the wings starting to sweep already at M 0.44, ..

If auto sweep starts at .44M which is around 350kts at sea level, the reasoning might perhaps be that 'they' considered flights arrive in -tight - formation, and would have their wings moving around the established 350kt, which was considered undesirable, not just for looks, then if you would change the procedure approach speed to a slower speed that would make the 'problem' of these moving wings only worse, one could also up the procedure speed, but then all recovering aircraft types would need to up their speed and still you would have wing movements in F14 flights, or you tell the F14 formations to lock their wings aft because 350kts is exactly about the speed which is where this is considered safe heading for the fantail break and voila, problem solved. And if it happens to look cool, that is just more money.

[Spurts]

1. You cannot "undersweep" the program. Progression in manual forward will stop when the wings reach the program minimum. IE, you cannot force 20 degrees when the programmed minimum is 40. The sweep override cover is only utilized in emergencies, and won't override the minimum.

 

It will in the sim if you pop the override cover and move it forward but do NOT push it back in. I experimented with this once and at low level I could not exceed about 0.95M even with a shallow dive. On the same token, but the opposite side, Manually sweeping aft will provide only one advantage, and it is very corner case... improved lateral/directional stability at max AoA. You can peg the AoA at 30 units and the nose will only slice when and where you rudder it to go.

 

For any practical purpose, you only ever should use Auto and Bomb. Auto is never too slow at sweeping to matter.

[Spiceman]

The sweep override cover is only utilized in emergencies, and won't override the minimum

 

No, the Emergency Wingsweep Handle is a direct cable linkage to the wingsweep drive servos and bypasses all CADC interlocks. The only interlocks that aren't bypassed are the flap interlocks, which are a hard mechanical interlock. The pilot assumes responsibility for manually implementing a wingsweep schedule that will not damage the airframe. The notches are there to prevent inadvertent movement of the handle.

[captain_dalan]

If auto sweep starts at .44M which is around 350kts at sea level, the reasoning might perhaps be that 'they' considered flights arrive in -tight - formation, and would have their wings moving around the established 350kt, which was considered undesirable, not just for looks, then if you would change the procedure approach speed to a slower speed that would make the 'problem' of these moving wings only worse, one could also up the procedure speed, but then all recovering aircraft types would need to up their speed and still you would have wing movements in F14 flights, or you tell the F14 formations to lock their wings aft because 350kts is exactly about the speed which is where this is considered safe heading for the fantail break and voila, problem solved. And if it happens to look cool, that is just more money.

Nah, the change in programming was done solely to benefit the excess power properties of the jet. While the original programming put emphasis on CLmax, but also put extra strain on the wings and the wing boxes.