F-15 Sea Eagle history (Naval version)

Cold war, Korea, Vietnam, and Desert Storm - up to and including for example the A-10, F-15, Mirage 200, MiG-29, and F-18.
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edpop

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Unread post01 Aug 2021, 05:58

Most aviation buffs will agree that within the diverse realm of military aviation, one of the most interesting topics of discussion is aircraft that never were. No, when I say “never were”, I’m most certainly not referring to black aircraft that “don’t exist”. Rather, we’re talking about aircraft designs that barely made it to the prototype stage before getting canned, or worse- they never left the drafting table before the project/concept was scrapped in favor of some other program. The 1970s, in particular, bore a few examples of a bunch of aircraft that never were. Let’s briefly talk about one of them.

The early ’70s saw the United States Navy test the Grumman F-14A Tomcat as a carrier-based fleet defense fighter; the eventual complete replacement for their F-4 Phantom IIs. However, the first problem with the Tomcat that immediately blew into the spotlight (other than its engines which had a nasty habit of stalling during certain maneuvers) was that it was a very costly aircraft. Granted, it fulfilled the needs of the VFX (Naval Fighter Experimental) Program almost perfectly, and looked every bit the part of an air superiority fighter that could actually live up to what Grumman promised it could do. However, money and budgeting has constantly been a concern of many a one-star admiral and above. That’s why in the early ’70s, the Navy very briefly entertained an interesting proposal from McDonnell Douglas. The aircraft they offered would function as an alternative to the costly, heavier and “riskier” F-14 Tomcat. It wasn’t an upgraded Phantom, McDonnell Douglas’ most successful fighter at that point in history, nor was it a clean-sheet design. In fact, the fighter jet MD executives offered the Navy was none other than the F-15 Eagle, then still being tested and developed prior to its integration into the United States Air Force’s inventories.

NavalF-15

At a first glance, the aircraft bore no drastic visual departures from the F-15A. It looked very similar, right down to the inclusion of a tailhook which was standard on the Eagle for short-field arrested landings (especially in emergency situations). However, the Eagle needed to be navalized. For storage in close proximity to other aircraft on the flight deck of an aircraft carrier, and for closed storage inside the massive hangar bays of a carrier, the wings would have to be shorted. Since this was impossible to do with the Eagle, the naval version would instead feature folding sections of the wings (a little more than 15.4 feet on both wings) that would lift up into right angles. That solved one problem. The next was the fact that carrier landings are usually very rough on an aircraft. Essentially a very highly-controlled crash, trapping aboard a carrier involves hitting the deck with your wheels and hopefully snagging one of three or four wires stretched across the angled deck. Added to the mix is the roll of the ship (it’s in the middle of the ocean, a bit of swaying is to be expected), and weather conditions. So instead of leaving the navalized F-15 with the Eagle’s original landing gear, McDonnell Douglas promised that if the jet was selected for further development, they’d redo the gear so that it could accommodate violent carrier landings with ease. Third was the tailhook. Yes, the land-based Eagle already came with one stock, but the naval variant would get an even stronger hook, as it would be used far more frequently than the regular F-15’s tailhook. It would have a higher rate of climb, max speed and combat range than the F-14A too. McDonnell Douglas engineers christened the proposed jet the F-15N Sea Eagle (I like to call it Seagle).

The Seagle, however, was afflicted with with a slew of issues that virtually doomed it from the get-go. The Navy (obviously in hindsight) found it less than satisfactory, and judged that the aircraft design failed to meet certain requirements that weren’t actually set for the hypothetical acquisition of such an aircraft, especially considering that the Navy was already gearing up to buy the Tomcat as their fleet-wide solution. Among the most glaring of these issues was the substantial weight of the jet. That, and the aircraft couldn’t carry the AIM-54 Phoenix, a missile the Navy felt showed considerable promise when paired up with the appropriate jet (namely the Tomcat). Temporarily undeterred, McDonnell Douglas got its engineers back to their drafting tables. The redesigned bird was deemed the F-15N-PHX, which would be able to carry (and deploy) a full load of Phoenix missiles. Once again, weight became an issue. The added weight of the missiles to the already-heavy jet would likely have had a significant negative impact on the combat performance of the aircraft, making it a far less feasible fighter to the F-14. The F-15N and F-15N-PHX never made it off the blueprint sheets, instead dying a very quick death after a Senate review in 1973.
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Vietnam veteran (70th Combat Engineer Battalion)(AnKhe & Pleiku) 1967
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Unread post01 Aug 2021, 16:28

"It would have a higher rate of climb, max speed and combat range than the F-14A too.."

I can see rate of climb and max speed perhaps, but range? With only 11,000lbs of internal fuel I think that'd be a stretch. The Cat carried 16,200lbs or so internally, and the external tanks held around another 4,000. They reportedly didn't add much drag either, or at least less than one might expect. I wouldn't even want to know how much drag external tanks on a Sea Eagle (plus combat load of missiles) would have been. Unless they had plans to use the CFT's?

At any rate, the Sea Eagle always seemed like a round peg in a square hole. Whereas the Tomcat always looked and functioned the part. Shame it didn't get better engines from the get go...
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Unread post01 Aug 2021, 22:08

F-15's carry significantly larger bags underwing than Tomcat had under each funnel. Perhaps F-15N had more fuel in a full load out?
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Unread post02 Aug 2021, 01:08

I'd have to look up this issue but I'll suggest that the TOMCAT could not arrest with a full load of missiles IIRC, highlighting the problem: Not only is weight an issue for catapult but particularly for the limitations of the arresting gear for an aircraft approach speed and maximum landing weight. Then there are minimums for approach fuel for various situations. An F-35 needs to be at or below 145 KIAS for an arrested landing at maximum arrest weight (which is quite high) but getting to those limits was problematic (don't mention the first arrest hook). :mrgreen: Go here for more:
Origins-The Story Of The Legendary F-14 Tomcat
14 Feb 2015 N.R.P.

"...There was also an option to carry 6 Phoenix missiles along with 2 Sidewinders, but this option was rarely used when operating from carriers as such a load made it impossible to land on a carrier unless the missiles were expended as it exceeded the carrier weight limitations during landing. So in an ideal combat mission, one of the above mentioned combination of AAMs were carried...." [see table at URL]

Source: https://defencyclopedia.com/2015/02/14/ ... 14-tomcat/
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mixelflick

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Unread post02 Aug 2021, 16:02

Yes it was well known (at last I thought it was) no F-14 could trap with 6 Phoenix, and any such loadout was usually for a photo op. Typical load I saw in the cold war was 2 Phoenix, 2 Sparrow and 2 Sidewinders, while wingman flew with 6 Sparrow and 2 sidewinder.

Alternatively each aircraft flew with a single Phoenix, 3 sparrow and 2 Sidewinders. Iranian fighters rarely carried 6 Phoenix (in fact, I've never seen it) despite the fact they could theoretically land with that full load. Two was usually the most, as any more I'm sure made it a dog and really put it at a disadvantage WVR.
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aaam

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Unread post02 Aug 2021, 20:59

On the F-14A there was also the problem of the miserable TF30 engines. A lot of performance was compromised when they were adopted (remember F-14 was designed around engines of 28,000 lbs thrust, instead of 20,900). This affected allowable weight on approach/trap, which also had to figure in the single engine waveoff case
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Unread post02 Aug 2021, 23:03

That it was impossible for the F-14 to trap with six AIM-54s is yet another myth about the Tomcat. On the F-14 Association Members page on FB, several former F-14 crew members stated that it could absolutely be done with a light fuel load.

From a gentleman who trapped with six AIM-54s:

"Flew with 6 many times while I was the Aim54C test director for OPEVAL. Plane had no problem coming back to the ship with a full load - but you were trick or treat on the ball. (One or two looks at the deck before you were on a tanker). Stations 1 and 8 (wing stations) were most reliable for temp conditions. With the right ROE - you had every chance of becoming an ace in one fight. BTW - AOA is a function of weight. Ordnance or fuel - pick your poison for weight."

It was a very impractical loadout for routine ops though. Realistically, six AIM-54s would only have been carried if the Cold War had suddenly gone hot hence the term "Doomsday Loadout".
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Unread post03 Aug 2021, 10:31

I'm on an extremely slow internet today so this post may not go well. 'Tiger05' explains the situation well and I may add 'to what Tomcat do we refer'? I have NATOPS for A,B & D versions but for the moment I'm only going to post a graphic of the table mentioned in my post above. Posting this may take ages unfortunately due to slow connection. NO GO at MOMENT.

He's back....
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