Heatloss

Boy, was I wrong. Went searching for information on AIM-7 as an Air to Ground weapon, ran across this. No time tonight to investigate further, but you might be interested. This is a manual dated 1970, with the black bar representing a change as of 1973.

Finally found a minute to drag out the F-4J tactical manual. NAVAIR 01-245FDB-1T, 1972.

First off, VTAS I was not a great system. It introduced too much clutter, lacked proper adjustments initially, and was quickly supplanted by VTAS II. VTAS II utilized reflection on one of the two visors in a dual visor system. HGU-37/P and HGU-46/P. I cannot tell you the exact weight differences, unfortunately. MDRs and FOIA requests have turned up blanks for the most part. Same with APX-80A/81. As for dying off. We've been over this. SEAM WAS CARRIED OVER. THIS IS THE SIDEWINDER OFF BORESIGHT PORTION OF VTAS. IT WAS USED WITH RADAR IN BOTH THE TOMCAT AND THE PHANTOM. THE VTAS HELMET JUST ALLOWED THE PILOT TO CONTROL THE SEEKERHEAD MANUALLY INSTEAD OF SLAVING TO RADAR. SEAM WORKED VERY WELL AS EARLY AS THE AIM-9G. SEAM worked so well, in fact, that it was carried on to the 9L. For a long time, air force sidewinders did not have the option to use SEAM. I have heard references to it being integrated into the 9P4 and 9P5, but those are in passing and have no sources to back them up. VTAS was binned because it was expensive. Radar only SEAM did 90% as well as VTAS SEAM, and you didn't have to get your helmet refitted every time you gained or lost a few pounds. Helmet fitting and VTAS calibration was a lengthy and expensive process for the navy. That is why they binned it, not effectiveness. As for the reason my profile picture is VTAS I, it has nothing to do with it being the more effective VTAS system or anything(it's not). It's just recognizable, and I think it looks cool. Even if pilots hated "granny glass".

I believe that was all of them. Cooling was provided by the pylon except for a short time that would be used for guidance. It's possible on the phantoms the falcons used the guidance liquid nitrogen to cool on the rail. I love the F-106. With IRST and radar locks checking one another through the fire control system, it provided a rudimentary way for the pulse system to see through clutter and different forms of ECM. Despite low reliability with early MA-1 systems, it was worth its weight in gold when it was needed. Integration with SAGE was quite neat too. Would make for an interesting GCI facet to a F-106 module. There are great reasons to do the 4E. I'd like to see a 4E, 4D and 4S. That would be ideal in my mind. The ultimate multirole, the falcon slinger, and the ultimate dogfighter of the line. The 4D could also perform most of the same tasks as a 4B or 4C in game.

I don't remember if that was corrected before the pylons on the F-4E, which I believe fixed it. But that may be very wrong. On proper pylons, such as the ones on the F-102, 106, 101, et cetera, they could cool for as long as twenty minutes.

Yes. It's been a long time, but yes. I'll try to track them back down but it may take days or weeks. I'm a busy guy, as you can probably guess from my sporadic responses. VTAS used the same circuits as slaving the seeker to the dish, except without moving the dish. I'll try to find the circuit diagram at some point here too. Out of 10 falcons fired in Vietnam, all 10 were fired out of the envelope. 8 didn't hit, and 2 failed due to other errors. Likely a seeker ran out of coolant. In tests, the lack of a proxy fuse hardly limited it. It was a perceived issue rather than an actual issue. The warhead in the superfalcons (G and F) also about the same size as early sidewinders. The 4D was impact and didn't really need the larger warhead. There were tests where the fuse failed and the missile ripped apart the target anyways, if memory serves. Fun fact, it had a boresight, sidewinder-esque mode which used proportional navigation for the entire flight instead of terminal guidance. You needed to press one button on the stick or throttle quadrant, I don't remember which one, and it would swap to this mode with the seeker caged at boresight. This was available on the F-4D and E. No pilot in southeast Asia was aware of it to the best of my knowledge.

I've never heard someone speak poorly about SEAM assisted AIM-9 launches before. Which is EXACTLY what VTAS was doing. Except it connected to your head instead of a radar lock. The Tomcat carried SEAM over, and it was maintained instead of VTAS because it was far, far, far cheaper, 90% as good, and required less training to use. The 9H was already one hell of a missile. Uncaging before launch became a thing as early as the 9G. I'm pretty sure it was there on the 9D as well, but I can't remember at the moment. That meant you could lock the target in boresight, hold the uncage switch, and let the missile follow your target. Made launches far easier, and nobody ever complained about that working to my knowledge. Hell, when lead calculation replaced proportional navigation of the AIM-9s with the 9L, missile turn performance mattered very little. The 9L and M have the same seeker head angle limitations as the 9D (CORRECTION, THEY HAVE GREATER LIMITATIONS. 22 DEGREES FOR 9G AND 9H, AND 40 FOR 9L AND M.) and very similar G limitations to the 9H, which the 9L was built on. Hell, Look at how well the superfalcons, which used lead calculating guidance instead of proportional navigation did on the F-106, especially with properly trained pilots who understood the fire control systems, unlike Robin Olds(not blaming him as much as I'm blaming SAC's complete lack of care of informing the USAF of how to train pilots to us the AIM-4D). The claim that VTAS was too "heavy and bulky" seems downright ridiculous to me. Have you ever handled one of those in the VTAS configuration? The difference in weight is practically none. The biggest hassle is the little wire sticking out the back. The issues with VTAS came with the normal weight of the helmet causing point of aim to shift in high G maneuvers, which just led to further improvements in helmet fitting. Now for the edit. After some searching, I finally found a source that can explain some of this. The weight difference was little, maybe a few ounces at most on the helmet, still clocking in at far lower than the 4 and a half pounds of JHMCS, but there was bulk added for sure. It appears based on the source I read that one major concern was that pilots that were not careful could smack the helmet into the side of the cockpit and damage the IR emitters. A few pilots found it to be more hassle than it was worth, and would simply fly the planes with a standard APH-6 helmet sans the VTAS equipment. However, a large number of pilots loved it, and continued to use it for the service life of the aircraft.

I'm not claiming at all that it was capable of taking on anything newer than a MiG-23MLD and winning. Also please for the love of god read about the glove vanes. I know without looking what chart you're seeing for the 14A turn performance. That is estimated performance before any serious flight tests had been done. They were very, very wrong.

Also, I missed something here. Yes, the N beating the 15A is down to pilot performance. VTAS may have made a slight difference, but the 4N is still a 4B with slight updates and modernization. As far as I am aware, it retained the same questionable vacuum tube APG-72 radar of the F-4B, while mainly changing up the aerodynamics, engines, and cockpit ergonomics.

I'll also add in that VTAS II was developed due to issues that pilots had with the Granny Glass VTAS I (coincidentally that equipment can be seen in my forum profile picture). http://www.best-of-flightgear.dk/vtassafe.htm here is a decent article which mentions explicitly that "[VTAS II], in sizes medium and large, is presently being flown in the fleet." VTAS I had issues which were identified on early usage between flight tests, and, if I remember correctly, limited combat deployment. VTAS II cannot be as easily visually identified, as it uses a secondary visor beneath the normal sun visor to reflect the image. It has a cable coming out of the back for power, but otherwise it looks much like a standard flight helmet of the era.

Everything I've read about it is that it was trialed on the eagle and tomcat, but determined to be too expensive and a hassle to use for those platforms, and that they had other features that made VTAS less worth it. However, I've seen that it was deployed to the entire J,N, and S fleet to great effect. If you check the F-4S SACs as late as 1984, they list VTAS in equipment, which aligns with everything I've read about its employment. There's no question the tomcat had an advantage in a one circle fight. That was by far its greatest advantage, until the 14B, which was the dogfighter of top gun lore. Check EM charts for the F-4E and the F-15A and C. The maneuverability in NASA, USAF, and third party EM and turn performance charts I can find have the 15A/C and the slatted F-4E as even. Key word, slatted. The J had a sustained of around 12/second, which was better than most MiG-23s, and better than early 21s, but not 14A, 15, or the MLD. The greatest weaknesses of the slatted phantoms in a dogfight was the lack of rearward visibility and worse performance in the vertical.

The E has comparable handling in most circumstances to the F-15A/C. The S is the same in a dogfight, except it has a HMD. Look up VTAS, introduced in 1969 on the F-4J. Between that and the AIM-9D/G/H, they never needed a gun. In a two circle or rate fight, the 4E and 4S should more than hold their own against a F-14A. The effect of glove vanes on turn was vastly overestimated, and in a sustained fight, the Phantoms reach their maximum rate at a far higher speed than the Tomcat-A. As for roll, they are roughly similar. To say that the Phantom handles like ass is buying into Robin Olds' trap and misses the incredible piece of engineering that was the later F-4s.