Adapting land based planes for carriers

You have indeed. The reason why Treasury imposed limits on defence spending was because the UK's economy was getting a battering after WWII. It didn't really have the chance to recover from its massive over-stretch during that conflict. Political decisions were made to spend what money there was, on the civilian population, rather than what were perceived as pointless armaments when the next war was going to all over in less than 15 minutes (and that includes the four minutes for the ICBM/IRBM's to reach the UK).

What I often find interesting in discussions about military history and technology is the way in each civilian political decisions and economic factors are so often disconnected and forgotten about in the delight of talking about the "Gee-whiz factor", as I call it. The UK made these decisions not necessarily because there were alternatives but rather because there weren't. It was a case of either a new carrier/aircraft/tank/missile/etc. or several new hospitals/schools/etc and guess which one got chosen because it would earn more votes?

The end result was, as I pointed out previously, that the RN ran out of money. It couldn't replace Ark Royal, so they got out of the CTOL fixed wing aviation business. The USN is rapidly looking like it may well be in a similar position as far as front-line fighters are concerned. It will be back to accepting second-best because it refuses to compromise, I'd suggested.
 
rickshaw said:
What I often find interesting in discussions about military history and technology is the way in each civilian political decisions and economic factors are so often disconnected and forgotten about in the delight of talking about the "Gee-whiz factor", as I call it. The UK made these decisions not necessarily because there were alternatives but rather because there weren't. It was a case of either a new carrier/aircraft/tank/missile/etc. or several new hospitals/schools/etc and guess which one got chosen because it would earn more votes?

It’s not as simple as that or you’re almost right but still so very wrong.

Much of the criticism in a more informed forum like this one is not levelled at the national leadership for not spending huge amounts on defence hell or highwater but on the defence leadership (both civilian and military) for wasting much of the defence monies. If this money was spent better, and usually this is about early risk assessment (ie engineering), then there is often enough to allow for proper force modernisation to meet the threat. Case in point is Sweden where thanks to their 450 year old defence materiel agency, the FMV, a country of only eight million people can design, build and enter into service large fleets of the world’s best tanks, submarines, fighters, etc

Much of the discussion in this forum is about projects that went wrong and the options that were available earlier. Case in point for naval aviation is the RN’s failed post war attempts to build a new carrier and the USN’s failed attempts in the 1980s and 90s to build a new naval tactical aircraft. The issues here were not necessarily overall defence funding but wasted investment.
 
Nope its not accurate at all. UK could've acquired at least one or two affordable CTOL CVs had it approached this task reasonably.
Had such been available in '66 the calculation would've been different.
Wilson faced the problem of not just keeping the existing disparate fleet funded, but also funding new larger and more expensive CVs to replace them. It was too much, and to cover the real reasons declared CTOL carriers unecessary, but subsiquent events rather flew in the face of that with the Beira patrol.

Indeed the UK did have the finance to persue Victorious's modernisation and the completion of Hermes and Ark Royal, as well as the modernisation of Eagle.
It did have the finace to expensively develope the NA39 winner.

But not the DH110 and the Type 556 together, they chose the nearterm option.....in 1954.....only for the whole effort to be delayed into service proper until 1960. Far too late for a machine the RN orriginaly hoped would be ISD by 1953!

What went wrong after was they overreached themselves, trying to jump a generation after that second haitus in 57 and combine RAF and FAA requirements in a machine that is'nt that far off the US's TFX. With predicable results.

They did'nt have the money to build a new CV in the late 50's AND a new drydock able to cope with it for military use.

They did'nt have the money to design and build a new CV design in the 1960''s using lots of all new technology. Mk6 catapults, Type 985 then Type 988 radars, SeaDart, ADAWS-3, 1000psi boilers, lightweight construction techniques, scissors lifts, all where new technology back then.
Especialy one whose design was driven by trying to match the needs to operate tacticaly useful numbers of OR346 types, within both budget and artificial constraints. Frankly shipyard staff to actualy build the thing was below the required numbers in the 1960s.
CVA-01 was as much overreach as OR346. The two interconnected, and the F4K does'nt solve a thing, in the cost of it makes things worse.

In fact the RNs numbers from the CVA-01 quick look studies and costings show the cheaper and more affordable option was a 42,000ton CV, (you can afford five of them for less than the cost of four 55,000ton CVs) but its aircraft numbers don't match logical division of their Tactical Air Unit once you change from NA39 to OR346.

Their numbers are pretty clear to anyone who looks at them, and likely if the Treasurey got their hands on them they'd clearly see the RN was planning a fleet of five CVA-01's and never stopped doing so despite all Treasurey advice and warnings.

They did have the chance to design and build a new moderate CV using known technology already paid for in the late 1950's. That is BS mk4 and mk5 catapults, Mk13 arrestor gear, Type 984 radar and CDS (even its successor ADA).

Medium Fleet CV is that ship, the prefered option from 1954, affordable and achievable, that fits the doctorin of the times. Flexible enough and cheaper to operate than Eagle and Ark Royal.
What went wrong was they where too cautious and held off on key decisions until it was too late.
Staff requirements should've been writen for it by the end of '54, instead they where tentatively discussed in '56.

Had -01 been ISD by 1964 its likely Ark Royal would've been paid off, she was in poor condition by '63. That leaves the logical decision on -02 to replace Eagle or Victorious later on.
 
Having a read through Stevenson’s 1970s F-15 book (and it is very good) I have summarised the following F-15N data.

In mid 1971 the US Navy sought data on a carrier suitable F-15 from McAir under direction of the SECDEF. McAir designed a minimum modification F-15N with 2,300 lbs extra for carrier suitability. This included strengthened landing gear for catapult tow, wing fold and a tailhook. Pilot view, takeoff and landing speeds and structural strength were all considered suitable. The F-15N was rated by McAir as suitable for down to CVA-19 (Essex) carriers which the F-4 and F-14 weren’t. What McAir didn’t add is Phoenix and the Navy study of the F-15N with Phoenix increased its weight, drag and cost so it wasn’t 'competitive' with the F-14 (so they say).

The second pass on the F-15N came in 1973 when the F-14 was in funding troubles (leading to the drop of the F-14B with F401, aka F100 engines). There was a DEPSECDEF effort to arrange a F-14 vs F-15 flyoff but funding wasn’t available. What arose from this was the idea for the NACF [Naval Air Combat Fighter] that was won by the F-18.

Despite being added Phoenix the F-14N with four of them would have a TOGW of 46,957 lbs vs 68,684 lbs for the F-14A (with four Phoenix). This still gives it a higher fuel fraction (0.25 vs 0.24) and far higher thrust to weight ratio and far lower wing loading on takeoff and landing. T/W on takeoff would have been 1.02 (F-15N) vs 0.59 (F-14A) and W/S (lbs/sq ft) 94 (F-15N) vs 122 (F-14A).

Before anyone gets all excited about how this disproves the need for purpose designed carrier suitable aircraft: the F-15 was designed by a naval fighter house – McDonnell Aircraft – towards an RFP specification that focused on many carrier suitable traits like – high T/W, low W/S, high forward pilot visibility, high -/+ G tolerances, STOL and so on... You couldn’t take a F-106 and turn it into a naval interceptor so easily.
 
Truthfully speaking, I think the F-15N would have been better. At least you wouldn't have had 16 years go by with the aircraft flying with an unsuitable engine.

KJ Lesnick
BTW: The F-15N was a single-seater or a twin-seater?
 
KJ_Lesnick said:
BTW: The F-15N was a single-seater or a twin-seater?

The book doesn't make a point of it and the one picture is posted earlier in the thread. It looks like a two seater canopy, but it wouldn't make that much difference on an F-15 as they were all built with the room for the second seat and instrument panel as spare space.
 
AeroFranz said:
F-14D said:
You could open quite a debate by calling the F/A-18 the greatest Navy plane. There are quite a few people (including me) who consider that airplane probably the most devastating thing to hit Naval Aviation in its histroy.

Amen to that. And how about the fact that Super Hornets -supersonic attack aircraft - are flying the tanker mission... Pretty soon we'll have a one-airplane Navy with F-18s flying the ASW and CODmission!

I agree with both these statements!
The USN has put too much faith in the F/A-18A/C and especially the F/A-18E/F designs
They have lost a true long-range medium attack, with the retirement and non replacement of the Grumman A-6 Intruder (and the lost opportunity of the A-6F)
It does seem a some what waist of capability in using the Super Hornet as a tanker.
Will the EF-18F Growler have the range and loitering time too be an effective replacement for the EA-6B Prowler?

Regards
Pioneer
 
More data on the F-15N, from the Flight archives:

Now just F-14/F-15 fly-off?
The US Deputy Defence Secretary, William Clements, has announced that the F-4 will not now take part in the proposed fly-off competition with stripped-down F-14s and strengthened F-15s to decide finally on a fighter for the US Navy (see Flight for June 21, page 938).
More at:
http://www.flightglobal.com/pdfarchive/view/1973/1973%20-%201883.html
 
The F-15N was rated by McAir as suitable for down to CVA-19 (Essex) carriers which the F-4 and F-14 weren’t.

Wow!
No mean feat if true.
Does this mean a dry thrust launch?

And one wonders about recovery of any large, heavy and fast aircraft on such short angled decks as on the modernised Essex types.

Has someone mentioned TO and L speed for this F15N?
 
zen said:
Has someone mentioned TO and L speed for this F15N?

F-15N takeoff and landing speeds would be roughly worse than the F-15A as it has an extra 2,000 lbs of deadweight. The F-15A’s level flight data gives it a minimum airspeed of 66 knots with four AIM-7 and a gross weight of 35,040 lbs... Probably be good enough to land on a Majestic class carrier...

The F-8E would trap about a SCB-125A Essex at 22,000 lbs and an approach speed of 140 knots (stall at 123 knots).
 
NASA report on F-15 landings:


Dynamic Ground Effects Flight Test of an F-15 Aircraft
www.nasa.gov/centers/dryden/pdf/88337main_H-1999.pdf
 
No not even at 66kts would a Colossus of Majestic handle this, since their limited majoritively to 24,000lb and one to 30,000lb aircraft.

A Centaur might, Hermes most likely, since it was thought possible with mk13 gear to land a 35,000lb machine at 97kts in 1952.
Victorious, Eagle and Ark Royal yes.

However that pdf is something to read, and while I've only had a quiick look through it might suggest a more normal figure of 150kts, which if we factor in a 25kt WOD means 125kts.

Err 22,000lb at 140kts is rather different from 35,000lb at 66kts, let alone the latter weight at 125kts.
 
The 150 knots landing speed in the NASA study is not the minimum landing speed of an F-15, it’s just what they used to get good ground effect data. I perhaps should have read through that study before linking it here as it didn’t have minimum landing speed data. The F-15 can do a loop at 150 knots so I think it can land at a much lower speed. 66 knots is the rated minimum speed for level flight at low altitude, before stalling. The STOVL F-15 S/MTD (Short Takeoff and Landing/Manoeuvre Technology Demonstrator) with canards and thrust vectoring nozzles was achieving take off rotation at speeds as low as 40 knots. However the F-15N would probably approach the carrier at 120 knots but would be able to do it with negative YOD and have huge reserves of lift for emergency climbing.

To landing on a Majestic type carrier, arrestor strength is usually classed by weight because most jet aircraft approach at the same speed (~120-125 knots). But it’s all about absorbing energy which is variablenot just by weight but by momentum which includes velocity. So a heavier aircraft, theoretically, could be stopped by a lighter weight arrestor system if it lands at lower speeds. Of course other issues like deck strength and so on are important.
 
Nothing wrong as such with what you say but...

Centaurs with mk13's are your limit I think on that.

mk12 as used on the Majestics and Colossii would not cope with a 35,000lb aircraft at 100kts (assuming a 20kt WOD)

Maybe 30,000lb at 60kts if I reccal correctly. Which was on the old Brazilian ex-Dutch ship, much modified and modernised.

So on the whole theres nothing wrong with the idea of a F15N operating in limited numbers from a small Fleet CV like Hermes.
Theres even nothing wrong with trying to produce a new CV of small size comparable to a Majestic to operate such an aircraft (shades of Trade Protection types from the 50's and comparable to the much smaller Harrier carrier ideas often bandied around).

Just the idea of trying to use it on a Majestic itself is thats wrong.

Interesting idea, though a Navalised F15.
 
Well it’s hardly an idea I’m trying to seriously pitch. It was an off the cuff emphasis point about how comparatively easy it would be to land an F-15 on a carrier compared to F-14s and F-18s with its very low wing loading and very high thrust to weight ratio.

I’m sure but if the F-15N had ever entered service then the USN and friends couldn’t resist landing one in low weight ‘Streak Eagle’ish configuration (~32-35,000 lbs) onto a Majestic just for the hell of it ;-)
 
It would've been a publicity stunt for sure ;D

The ship would've been reinforced specialy the F15N stripped of every superfluous item (shades of SteakEagle there).

Now had this been the 70's, they could've done it from the old Ark Royal for real as a sales pitch, which would certainly be a interesting thing to have seen.
But I think Hermes was stripped of her CTOL equipment before such a F15-N would've been available even as a prototype.
 
just to add something but which might be superflous , this Spitfire fan (who became a fan due to Mk1 assembled without glue he kept on the top of the clothes rack and how nice a blue colour it was ) has recently read that out of 106 Seafires attached to a landing in Italy 40 crashed and only 6 or 8 were left operational , but the conditions were less than ideal .
 
r16 said:
just to add something but which might be superflous , this Spitfire fan (who became a fan due to Mk1 assembled without glue he kept on the top of the clothes rack and how nice a blue colour it was ) has recently read that out of 106 Seafires attached to a landing in Italy 40 crashed and only 6 or 8 were left operational , but the conditions were less than ideal .

They were using escort carriers, which weren't really suitable for either high-intensity operations nor operating Seafires with their comparatively high approach speeds.
 
nor there was wind to assist , yet ı would believe British interests would be better served by keeping the Spitfire on land .
 
"..keeping the Spitfire on land ."

Maybe the Spitfire/Seafire is not the best example !
IIRC, "Winkle" Brown said, that is was "a really beautiful aircraft in the air, but it really
should have staid there" and I think, this statement wasn't limited to using the Spitfire
from a ships deck.
The SeaHurricane, I think gave much less trouble, the only point against it was, that it
was never fitted with folding wings.
 
KJ_Lesnick said:
Truthfully speaking, I think the F-15N would have been better. At least you wouldn't have had 16 years go by with the aircraft flying with an unsuitable engine.

KJ Lesnick
BTW: The F-15N was a single-seater or a twin-seater?

But you would have almost a decade go by before you got a good engine. The F100 didn't start getting good until it was faced with competition from the F110.

To use AWG-9, it would have to be a two seater, plus the Navy was convinced (correctly) that it's nearly always better for a fighter to be two-crew.
 
I'd like to throw out a few thoughts here,, for what they're worth. Since they touch on so many posts, and I'm not that good at splicing in multiple quotes, I'll just fire away:


1. F-15N operating an Essex (actually Ticonderoga class), while F-4 and F-14 couldn't, according to McAir. Well, of course they'd say that. In point of fact, the F-14 had a requirement to operate from those same carriers as well; that was the reason for its very low approach speed. However, that requirement was dropped because a) the Gov't failed to deliver an engine of the specified thrust and weight that made it feasible. b) It was clear in the early '70s that this class of carrier wasn't going to be with us for many more years anyway, so it wasn't worth the trouble and expense to have this capability. There was also the issue with both aircraft of the "Yellow Gear" on such a small carrier.

2. F401 dying through lack of funding. Technically correct, but there's more to it than that. The Air Force at this time was encountering developmental problems with the F100. Reliability in the test program was not up to snuff and the engine was not taking well to rapid changes in fuel flow. The F100 engine at this point in time was more critical to USAF than the F401 was to the Navy. Although the F401 was the engine around which the F-14 was designed and provided the thrust levels and sfc benefits to allow the F-14 to meet its design specifications, the Tomcat was flying successfully with the TF30. Without the F100, though, there could be no F-15. USAF knew that given enough time they would solve the early F100 problems. In fact, they eventually did in the next decade (partly by derating the engine), but at this juncture it didn't look like Congress was going to give them the necessary time. One of the most critical tests was the 150 hour run, wherein an F100 would have to run for 150 hours without failing. Congress had made it clear that without passing this test funding for the F100 would disappear, and the Eagle would remain grounded. Published reports at the time were somewhat confusing about the definitive 150 qualification test. According to some reports, on the critical test the engine was closely monitored and if certain key components appeared that they were about to fail, the test was suspended, the component replaced, and then continued. The F100 engine passed the test. Once the F100 passed the 150 hour qualification test the Air Force was no longer responsible for reliability and endurance improvements in the common core. At this point the Navy was on its own, and had to accept the core in its current state. Any desired core improvements would have to be funded solely by the Navy. The Navy took a look at what it would cost to bring the core up to an acceptable level of reliability and performance to bring the F401 into service and decided it just wasn't worth it, and so abandoned the engine in April, 1974. It wasn't until the arrival of the F110 that the Tomcat got the engine around which the plane had been designed. It has also been said that it wasn't until the arrival of the F110 that Pratt got serious about improving the F100's reliability and performance.

3. F-15N vs F-14 wing loading. It appears when deriving those numbers, you used the figure of 565 ft2 for the lifting area of the Tomcat. This ignores the entire tunnel area, which is a lifting body that adds 443 ft2 once the wings sweep. Using the full lifting area would give a ratio of 68, not 122 for the F-14 vs 94 for the F-15. This is one of the reasons that an F-14 at comparable T/W ratios outturned the F-15 (unless the TF30s were acting up in the F-14, unless the F100s were acting up in the F-15).

4. F-15 doing a loop at 150 knots IAS. Yes, it probably can, under the right conditions and at a safe altitude, but keep in mind that going up it’s under full a/b, not a normal condition on approach, and on the other half it’s going down rapidly, also something you probably wouldn’t want to do with the ocean filling your windscreen. The ability to do this would really have no relevance to landing on a carrier, as would a stalling speed that’s partly achievable due to downward thrust at extreme AoAs.

5. F-15N itself. Without massively redoing the wing and control surfaces I would find it hard to believe that the -15N would have an approach speed of 120 knots. Keep in mind the even the “light” F/A-18A, which was designed to be carrier compatible from the get-go can’t do that. Also, you have to keep the nose where you can see the MLS and deck. Lots of a/c can fly really slow if you point th nose at the stars. F-14 is something like 45 knots. Hey, the Mig-29 and SU-27 can do zero! In any case, the original impetus for the -15N was a push by McAir to try and sell more of their planes (can’t blame them). The “flyoff” idea was never serious, IMHO, but a way to placate Congress. It would cost a fortune to do, and while valuable would only mostly tell you what you already knew. ,Just assume that both planes would do what their manufacturers promised. What do you learn? Actually, there was sort of a “flyoff” once-the second Iranian fighter order (under the Shah). Both the F-15 and F-14 were involved. The F-15 flew first and gave its usual eye-watering performance and there were some really neat shots of it making its really tight turns as it headed back onto the base for the next maneuver. The F-14 flew next, and essentially matched the Eagle’s performance (with couple of extras thrown in), with one notable difference: it was able to do all that within the airfield’s perimeter. This was a contributing, but not the only factor in why Iran bought the F-14 on both buys. As an aside, one of the big reasons there weren’t more F-14 export orders is that except for Iran, the US wouldn’t allow the aircraft to be exported (although they probably would have made an exception of the UK).

In any case, in order for the F-15N to be a viable concept the Navy would have to relax its requirements to whatever the -15N was capable of (shades of the Hornet!). Range and endurance, sensor performance, etc. . Because of the funding issues (mostly caused by the Gov’t) the F-15N was at least considered, but what really doomed the idea was that it would have cost more to “navalize” and equip the Eagle for the Navy than the amount of the funding issues with the F-14, and you would have ended up with a less capable, less versatile aircraft. No reflection on the Eagle, just that’s why the Tomcat cost more (along with production rates). Also, there was really no need to take on a new aircraft with a more expensive, unreliable engine when the Navy already had a less-expensive unreliable engine of its own.

Because of this and due to massive and effective lobbying by the light fighter lobby, it was decided to develop a “Naval Air Combat Fighter”, as the Air Force was doing because of pressure over the cost of the F-15. Not too far into that, Congress weighed in and decreed that the NACF would be required to be a derivative of the USAF’s ACF.
 
zen said:
The F-15N was rated by McAir as suitable for down to CVA-19 (Essex) carriers which the F-4 and F-14 weren’t.

Wow!
No mean feat if true.
Does this mean a dry thrust launch?

And one wonders about recovery of any large, heavy and fast aircraft on such short angled decks as on the modernised Essex types.

Has someone mentioned TO and L speed for this F15N?

In order to operate from a Essex/Ticonderoga, the launch would have to be dry thrust or minimum a/b because if nothing else the flame arrestors on the catapults couldn't handle what came out of the back of the jet at max a/b. On the Forrestal and later CVs, the arrestors were modified to be water cooled for the F-14, so the problem would be even more for a higher thrust engine. There wasn't room in the Ticonderogas, I believe, for this gear. The idea for the smaller carriers was that you would never go off the deck on a Ticonderoga with four + AIM-54s, it would be an AIM-7/AIM-9 loadout. The was intended to have as much thrust a military power as the TF30 did in max a/b, and that's how the goal would be achieved. When the F401 died, that dram tically impacted the ability to operate from the smaller carriers. Even though it was lighter, I'm not sure you could have gotten an F-15N off the deck except with a dramatically reduced payload without using a/b, even if you could have gotten it on the deck.

BTW, an F/A-18 couldn't operate from those smaller carriers either.
 
F-14D said:
2. F401 dying through lack of funding. Technically correct, but there's more to it than that. The Air Force at this time was encountering developmental problems with the F100. Reliability in the test program was not up to snuff and the engine was not taking well to rapid changes in fuel flow. The F100 engine at this point in time was more critical to USAF than the F401 was to the Navy. Although the F401 was the engine around which the F-14 was designed and provided the thrust levels and sfc benefits to allow the F-14 to meet its design specifications, the Tomcat was flying successfully with the TF30. Without the F100, though, there could be no F-15. USAF knew that given enough time they would solve the early F100 problems. In fact, they eventually did in the next decade (partly by derating the engine), but at this juncture it didn't look like Congress was going to give them the necessary time. One of the most critical tests was the 150 hour run, wherein an F100 would have to run for 150 hours without failing. Congress had made it clear that without passing this test funding for the F100 would disappear, and the Eagle would remain grounded. Published reports at the time were somewhat confusing about the definitive 150 qualification test. According to some reports, on the critical test the engine was closely monitored and if certain key components appeared that they were about to fail, the test was suspended, the component replaced, and then continued. The F100 engine passed the test. Once the F100 passed the 150 hour qualification test the Air Force was no longer responsible for reliability and endurance improvements in the common core. At this point the Navy was on its own, and had to accept the core in its current state. Any desired core improvements would have to be funded solely by the Navy. The Navy took a look at what it would cost to bring the core up to an acceptable level of reliability and performance to bring the F401 into service and decided it just wasn't worth it, and so abandoned the engine in April, 1974. It wasn't until the arrival of the F110 that the Tomcat got the engine around which the plane had been designed. It has also been said that it wasn't until the arrival of the F110 that Pratt got serious about improving the F100's reliability and performance.

So you're saying the USAF cheated during the 100 hr test? If so, why didn't the USN do the same thing?

Why was the USAF no longer responsible for any reliability and endurance improvements once it passed the test, and the USN was simply on it's own and had to accept things as they were? That sounds totally messed up (as in unfair)

3. F-15N vs F-14 wing loading. It appears when deriving those numbers, you used the figure of 565 ft2 for the lifting area of the Tomcat. This ignores the entire tunnel area, which is a lifting body that adds 443 ft2 once the wings sweep. Using the full lifting area would give a ratio of 68, not 122 for the F-14 vs 94 for the F-15. This is one of the reasons that an F-14 at comparable T/W ratios outturned the F-15 (unless the TF30s were acting up in the F-14, unless the F100s were acting up in the F-15).

Why is the tunnel's lifting effects only added after the wings sweep? Wouldn't it always be producing lift?


KJ Lesnick
 
KJ_Lesnick said:
So you're saying the USAF cheated during the 100 hr test? If so, why didn't the USN do the same thing?

Why was the USAF no longer responsible for any reliability and endurance improvements once it passed the test, and the USN was simply on it's own and had to accept things as they were? That sounds totally messed up (as in unfair)



Why is the tunnel's lifting effects only added after the wings sweep? Wouldn't it always be producing lift?


KJ Lesnick



It wasn't so much cheating as exploiting a loophole to save the F-15 on the 150 hour test, since the requirement didn't explicitly state 150 continuous hours using all the same parts that were present when the test started, although that was clearly what everyone expected and had always been the standard before As far as the USAF/USN responsibilities go, the joint development agreement was that since USAF was going to be buying the lion's share of the engines, they would be responsible for the larger part of the costs for developing the core and the common parts. Once USAF declared that phase completed and they accepted the F100, the Navy would be responsible for all development costs incurred for unique items to produce the F401 version. It was expected this would include marinization, JP5 fuel feed, reduced sfc, the larger fan, more powerful afterburner and the like. USAF said that since they had accepted the F100 in its present state, any increase in reliability beyond what the F100 demonstrated so far was a Navy unique requirement and they didn't have to fund it. Fair? This isn't unique. Why, for example, did USAF lobby so heavily to kill the Navy/USMC Bulldog laser guided missile and insist that everyone had to use their existing-only-on-paper, much more expensive Laser Maverick and then, once Bulldog development was dead, declare that they had no need for a laser guided missile and that Navy/USMC should fund all the development for Laser Maverick if they wanted it? "Fair" doesn't enter into these things.

The lifting body's effects are there at all times, but really come into their own as the wing sweeps back and you have essentially a tailed delta. At the lower speeds where the wing is still forward, the fact that you have what is almost a straight wing planform contributed more than the lifting body to the Tomcat's tight turning ability
 
F-14D said:
It wasn't so much cheating as exploiting a loophole to save the F-15 on the 150 hour test, since the requirement didn't explicitly state 150 continuous hours using all the same parts that were present when the test started, although that was clearly what everyone expected and had always been the standard before

Was the 150 hr test required for the USN as well? And did similar rules apply?


As far as the USAF/USN responsibilities go, the joint development agreement was that since USAF was going to be buying the lion's share of the engines, they would be responsible for the larger part of the costs for developing the core and the common parts. Once USAF declared that phase completed and they accepted the F100, the Navy would be responsible for all development costs incurred for unique items to produce the F401 version.

Why the hell did the USN want the F-401? The F-100 was a better engine and evolved out of the F-401, it produced more thrust, and was capable of higher-speeds, right?

It was expected this would include marinization, JP5 fuel feed, reduced sfc, the larger fan, more powerful afterburner and the like.

-What requirements are necessary for marinization?
-I didn't know it was a big difference to use JP-4 or JP-5
-How much of a difference in SFC would be needed?
-Why would you want a larger fan and a bigger burner -- I thought the F-100 was more powerful?


Why, for example, did USAF lobby so heavily to kill the Navy/USMC Bulldog laser guided missile and insist that everyone had to use their existing-only-on-paper, much more expensive Laser Maverick and then, once Bulldog development was dead, declare that they had no need for a laser guided missile and that Navy/USMC should fund all the development for Laser Maverick if they wanted it?

Why did the USAF want the Maverick so bad? Was the Bulldog a better weapon then the Maverick?

"Fair" doesn't enter into these things.

And unfortunately the USAF has much better lobbying capability than the USN

The lifting body's effects are there at all times, but really come into their own as the wing sweeps back and you have essentially a tailed delta. At the lower speeds where the wing is still forward, the fact that you have what is almost a straight wing planform contributed more than the lifting body to the Tomcat's tight turning ability

Wasn't the F-14's wing-loading with the wings swept all the way back still better than an F-15 with it's fixed large wing? If I recall it was 60.6 lbs/ft^2 for the F-15A, and 55 lbs/ft^2 for the F-14 with her wings all the way back...


KJ Lesnick
 
F-14D said:
In the old days, the Navy used to require Enormous amounts of paperwork, which was often hard to decipher if you didn't have a familiarity with the way the Navy did things. They actually didn't get better, everyone else just "caught up". And even thought that was the 15th rule, Lockheed was eager to be on the AX-A/FX program. Unlike the ATA, to Lockheed (and a lot of folks in the fleet) A/FX actually made sense.

Not to reply twice in a row, but...

Why did the USN do this? And at what point in time did everyone else "catch-up"?


KJ Lesnick
BTW: I just read one of your posts which said the P&W F-100 didn't begin to evolve into a good engine until the GE F-110 came along. Do you mean when the F-100 and F-401 were being initially developed? Or do you mean in the late 1970's when the F-15C was built? If the former, how much of a difference was the F-100 from the F-401 originally, and finally -- Meaning when the F-100 and F-401 designs finally ready to go into service? And if the latter, the primary improvement I assume was the revised fuel-control system, no?
 
KJ_Lesnick said:
F-14D said:
It wasn't so much cheating as exploiting a loophole to save the F-15 on the 150 hour test, since the requirement didn't explicitly state 150 continuous hours using all the same parts that were present when the test started, although that was clearly what everyone expected and had always been the standard before

Was the 150 hr test required for the USN as well? And did similar rules apply?

As far as the USAF/USN responsibilities go, the joint development agreement was that since USAF was going to be buying the lion's share of the engines, they would be responsible for the larger part of the costs for developing the core and the common parts. Once USAF declared that phase completed and they accepted the F100, the Navy would be responsible for all development costs incurred for unique items to produce the F401 version.

Why the hell did the USN want the F-401? The F-100 was a better engine and evolved out of the F-401, it produced more thrust, and was capable of higher-speeds, right?




It was expected this would include marinization, JP5 fuel feed, reduced sfc, the larger fan, more powerful afterburner and the like.

-What requirements are necessary for marinization?
-I didn't know it was a big difference to use JP-4 or JP-5
-How much of a difference in SFC would be needed?
-Why would you want a larger fan and a bigger burner -- I thought the F-100 was more powerful?




Why, for example, did USAF lobby so heavily to kill the Navy/USMC Bulldog laser guided missile and insist that everyone had to use their existing-only-on-paper, much more expensive Laser Maverick and then, once Bulldog development was dead, declare that they had no need for a laser guided missile and that Navy/USMC should fund all the development for Laser Maverick if they wanted it?

Why did the USAF want the Maverick so bad? Was the Bulldog a better weapon then the Maverick?



"Fair" doesn't enter into these things.

And unfortunately the USAF has much better lobbying capability than the USN

The lifting body's effects are there at all times, but really come into their own as the wing sweeps back and you have essentially a tailed delta. At the lower speeds where the wing is still forward, the fact that you have what is almost a straight wing planform contributed more than the lifting body to the Tomcat's tight turning ability

Wasn't the F-14's wing-loading with the wings swept all the way back still better than an F-15 with it's fixed large wing? If I recall it was 60.6 lbs/ft^2 for the F-15A, and 55 lbs/ft^2 for the F-14 with her wings all the way back...


KJ Lesnick

Addressing your questions in order:


The USN had equivalent testing criteria, but they weren't exactly the same. Also, the R&D agreement specified how certain things were to be tested.


Because the F100 wasn't designed to meet the Navy's needs. Remember, though, the F100 & F401 were being developed simultaneously around a common core from the Air Force's Advanced Technology Engine program. The F401 used the same core as the F100 with a bigger fan, different afterburner, better sfc and fuel control and was marinized.

Going into all that is involved in marinization is too much in the weeds for this forum. Just think of it as, "everything involved in having to operate in a salt water environment all the time".

The bigger fan was for the much longer loiter time and more thrust at all speeds the F-14 mission required relative to the F-15. The F401 was to be at least 10% more powerful than what the F100 was supposed to deliver. In reality, if it would have worked, it would have ended up being 20% more powerful, due to the derating of the F100 to meet its reliability criteria. Of course, if they had to derate the F100 they almost certainly would have had to derate the F401.

USAF actually didn't want Laser Maverick, they just wanted to make sure that USN/USMC didn't get to have their own missile. Bulldog took the existing USN/USMC Bullpup inventory and added a (USAF developed, actually), laser seeker. It had the advantage of already having the right type and weight of warhead, which Maverick didn't, and was compatible with existing USN launchers, which Maverick wasn't.

Depends on the weights. I simply ran the numbers using the weights Abraham was using.
 
KJ_Lesnick said:
F-14D said:
In the old days, the Navy used to require Enormous amounts of paperwork, which was often hard to decipher if you didn't have a familiarity with the way the Navy did things. They actually didn't get better, everyone else just "caught up". And even thought that was the 15th rule, Lockheed was eager to be on the AX-A/FX program. Unlike the ATA, to Lockheed (and a lot of folks in the fleet) A/FX actually made sense.

Not to reply twice in a row, but...

Why did the USN do this? And at what point in time did everyone else "catch-up"?


KJ Lesnick
BTW: I just read one of your posts which said the P&W F-100 didn't begin to evolve into a good engine until the GE F-110 came along. Do you mean when the F-100 and F-401 were being initially developed? Or do you mean in the late 1970's when the F-15C was built? If the former, how much of a difference was the F-100 from the F-401 originally, and finally -- Meaning when the F-100 and F-401 designs finally ready to go into service? And if the latter, the primary improvement I assume was the revised fuel-control system, no?

As to why the Navy was the way it was, that goes back to coming from a shipbuilding environment where specifications had to be much more rigid than the other services because you couldn't just pull over to the side of the road or land in a filed if something went wrong. Also you're into bureaucraticy 101. With all the things Congress has imposed on everyone, the rest of the services were just as bad by the late -80s (except for USMC).


I don't understand your second question. Basically, the bottom line was that when the services had nowhere else to go, Pratt had no real incentive to fix the F100. When GE started offering an engine that was more powerful, and better performance and more reliable, customers started buying that engine instead. At that point, Pratt sat up and took notice and started making the F100 what it always should have been.
 
F-14D
The USN had equivalent testing criteria, but they weren't exactly the same. Also, the R&D agreement specified how certain things were to be tested.

Understood

Because the F100 wasn't designed to meet the Navy's needs. Remember, though, the F100 & F401 were being developed simultaneously around a common core from the Air Force's Advanced Technology Engine program. The F401 used the same core as the F100 with a bigger fan, different afterburner, better sfc and fuel control and was marinized.

Going into all that is involved in marinization is too much in the weeds for this forum. Just think of it as, "everything involved in having to operate in a salt water environment all the time".

How much did it take to marinize the engines? Was that where the bulk of the cost lied? If not, where did the bulk of the cost lie?

(Out of curiousity, how hard was it to marinize the F110 for USN use)

The bigger fan was for the much longer loiter time and more thrust at all speeds the F-14 mission required relative to the F-15.

Could the F401 reach the same top-speeds as the F100? Because, one of the requirements for the FX was that it was to be as fast as a MiG-25

The F401 was to be at least 10% more powerful than what the F100 was supposed to deliver. In reality, if it would have worked, it would have ended up being 20% more powerful, due to the derating of the F100 to meet its reliability criteria. Of course, if they had to derate the F100 they almost certainly would have had to derate the F401.

Probably true...

USAF actually didn't want Laser Maverick, they just wanted to make sure that USN/USMC didn't get to have their own missile.

Why did they not want the USN and USMC to get their own missile? Why such a spiteful decision, when the USAF could use that missile too?

Bulldog took the existing USN/USMC Bullpup inventory and added a (USAF developed, actually), laser seeker. It had the advantage of already having the right type and weight of warhead, which Maverick didn't, and was compatible with existing USN launchers, which Maverick wasn't.

So it was a Bullpup with laser instead of radio-signal guidance?


As to why the Navy was the way it was, that goes back to coming from a shipbuilding environment where specifications had to be much more rigid than the other services because you couldn't just pull over to the side of the road or land in a filed if something went wrong.

That actually makes sense...

Also you're into bureaucraticy 101. With all the things Congress has imposed on everyone, the rest of the services were just as bad by the late -80s (except for USMC).

So the Navy didn't get easier... all the other services simply got more difficult when asking for specifications? How did the USMC get around the problem?

I don't understand your second question. Basically, the bottom line was that when the services had nowhere else to go, Pratt had no real incentive to fix the F100. When GE started offering an engine that was more powerful, and better performance and more reliable, customers started buying that engine instead. At that point, Pratt sat up and took notice and started making the F100 what it always should have been.

They didn't have incentive because they didn't have the money to make the engine better then?


KJ Lesnick
 
KJ_Lesnick said:
F-14D
The USN had equivalent testing criteria, but they weren't exactly the same. Also, the R&D agreement specified how certain things were to be tested.

Understood

Because the F100 wasn't designed to meet the Navy's needs. Remember, though, the F100 & F401 were being developed simultaneously around a common core from the Air Force's Advanced Technology Engine program. The F401 used the same core as the F100 with a bigger fan, different afterburner, better sfc and fuel control and was marinized.

Going into all that is involved in marinization is too much in the weeds for this forum. Just think of it as, "everything involved in having to operate in a salt water environment all the time".

How much did it take to marinize the engines? Was that where the bulk of the cost lied? If not, where did the bulk of the cost lie?

(Out of curiousity, how hard was it to marinize the F110 for USN use)

It was designed that way from the start

The bigger fan was for the much longer loiter time and more thrust at all speeds the F-14 mission required relative to the F-15.

Could the F401 reach the same top-speeds as the F100? Because, one of the requirements for the FX was that it was to be as fast as a MiG-25


It's not how fast the engine goes, it's the plane that it's in and that's due to a number of factors including drag, whether you need to sustain it, etc. An F401 powered Tomcat might be a few knots slower at the very top end because of more fan drag, but very, very little time is ever spent there. The requirement was M2.2 +and all versions of F-14s can do better than that. I believe the highest sustained performance every publicly disclosed for an F-14 was M2.5 @ 70,000 feet, which officially is above both its speed and altitude limits. There was no requirement for FX to match MiG-25 speeds. In fact, an F-15 can not catch a MiG-25 if the Foxbat can make it to cruise, however a missile can. IN the case of the Tomcat, an AIM-54 definitely can knock down a Foxbat no matte re where the MiG is at, as the Iraqiis learned to their regret.


The F401 was to be at least 10% more powerful than what the F100 was supposed to deliver. In reality, if it would have worked, it would have ended up being 20% more powerful, due to the derating of the F100 to meet its reliability criteria. Of course, if they had to derate the F100 they almost certainly would have had to derate the F401.

Probably true...

USAF actually didn't want Laser Maverick, they just wanted to make sure that USN/USMC didn't get to have their own missile.

Why did they not want the USN and USMC to get their own missile? Why such a spiteful decision, when the USAF could use that missile too?


They're the Air Force and have a history of doing stuff like that. They're very jealous of their "roles and missions", and even if they don't have the intention of doing something, they may not want another service to have the capability.



Bulldog took the existing USN/USMC Bullpup inventory and added a (USAF developed, actually), laser seeker. It had the advantage of already having the right type and weight of warhead, which Maverick didn't, and was compatible with existing USN launchers, which Maverick wasn't.

So it was a Bullpup with laser instead of radio-signal guidance?

Yes, with laser homing rather than steered by the pilot of the launch aircraft


As to why the Navy was the way it was, that goes back to coming from a shipbuilding environment where specifications had to be much more rigid than the other services because you couldn't just pull over to the side of the road or land in a filed if something went wrong.

That actually makes sense...

Also you're into bureaucraticy 101. With all the things Congress has imposed on everyone, the rest of the services were just as bad by the late -80s (except for USMC).

So the Navy didn't get easier... all the other services simply got more difficult when asking for specifications? How did the USMC get around the problem?

They're results oriented and they keep their word. They're the only service that contractors are willing to spend big amounts of their own money without a contract because if the Marines tell them they're going to buy something if it meets specs, they don't bail on them and move heaven and earth to get it.

I don't understand your second question. Basically, the bottom line was that when the services had nowhere else to go, Pratt had no real incentive to fix the F100. When GE started offering an engine that was more powerful, and better performance and more reliable, customers started buying that engine instead. At that point, Pratt sat up and took notice and started making the F100 what it always should have been.

They didn't have incentive because they didn't have the money to make the engine better then?

No, they knew the services had nowhere else to go, so why spend a bunch of your own money if you're going to get the sale anyway?
 

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