MOTS Phantom for the RN?

[Rule of cool]

I'm not comfortable with those margins, I could imagine them causing problems exactly when the RN was most vulnerable.

 

[MadRat]

So basically COTS Phantoms were not much different in practice on UK carriers than Spey-powered Phantoms with telescoped legs?

 

[orlovsky]

So basically COTS Phantoms were not much different in practice on UK carriers than Spey-powered Phantoms with telescoped legs?

The longer nose gear delivered, about 12 kts.
From the numbers around, my conclusion is that the Spey made no difference in carrier suitability.

I'm not comfortable with those margins, I could imagine them causing problems exactly when the RN was most vulnerable.

RN would have preferred more and probably expected more from the sales pitch - but went with what the F-4K actually delivered. For the F-4J, the RN would have had to accept that performance from the start.

 

[Rule of cool]

RN would have preferred more and probably expected more from the sales pitch - but went with what the F-4K actually delivered. For the F-4J, the RN would have had to accept that performance from the start.

IIUC then it comes down to timing for a MOTS buy. In 1963-64 the RN was looking at the F4B, which did need the Speys, but when it came time to actually build the aircraft in ~1967 they wanted them based on the F4J which didn't fly until May 1966.

To go with the F4J as a MOTS buy the RN would need to know it was under development early in their process, be comfortable that it would meet their requirements, be confident that it would enter production and that the US would let them buy it. That's a lot of 'ifs' that going with the Spey, that McD themselves proposed in about 1963, would ameliorate. All for the low low price of 25 million pounds development money and some 40% of the aircraft by value would be spent in Britain saving even more precious foreign exchange. Sounds awesome, lets do it!

 

[orlovsky]

The F-4K was discussed as a spey-engined F-4J in early 1964, just see the report posted here:

https://www.secretprojects.co.uk/threads/planned-uk-carrier-order-of-battle-1975.20517/page-2#post-420283

Both options were considered:



From this, it is clear that the F-4J with the longer nose gear would have worked from the 199ft catapult, with even the high hopes for the spey showing only marginal improvement; a larger difference was expected with the shorter catapults and slower Hermes:




In reality, the spey version fell at least 10 kts/4000lbs short of expectations.

 

[alertken]

Tory Minister Thorneycroft in '62 imposed, McNamara-like, commonality for the Hunter/Sea Vixen replacement. He selected P.1154 18/2/63 (BS.100, 25/3/63), RAF (1-seat) +RN (2-seat).
1/64 (why not 2/63?) he was told 2 engines were vital overwater, VTOL not, so RN 27/2/64 was allowed to escape P.1154B.
He accepted that a MOTS F-4B would arrive sooner/cheaper than an RN-peculiar P.1154, which might also disrupt work on RAF's variant. He authorised R&D for a reheated Spey, but did not then fund $ work, as an Election must soon be held.

New Ministers 27/10/64 funded 4xYF-4K, not fixed price as it was evolving from an F-4B to an F-4J base. They also funded R&D on Spey (to be) 202, though that added (unknown) cost/time. I do not know if jobs led that decision, or if they had been told J79 was incompatible with Ark/Eagle/Victorious - at all, or at tolerable safety. Ministers do not/cannot read graphs, but rely on professionals for techno-input.

CAS knew he had inherited from (now DSACEUR) MRAF Pike a programme that new Ministers would not buy: replacements for Shackleton MR, Beverley/Argosy transports, Canberras, Hunters, plus 5xSSBN, plus...plus...DoD offered US-standard products at fixed Unit prices and on deferred payment terms. Inter-operation with US and other Allies...fixed prices...credit...piles of parts: what's not to like?

Min Defence Healey asked simple Qs on P.1154: on the Central Front, what sortie has VTO+supersonic; in NEAF/FEAF why VTOL at all?
If CAS had said: "so we can operate after AW on our runways"...Ministers might buy no tactical type, and just fund MAD.
If an iron interlude is realistic, runways would be intact, awhile. So RIP P.1154/RAF, 2/2/65. He asked for 175 Long-TOL F-4D/J79, NOW!

The case then made to Ministers was that RN's bolter case required slam reheat, which Spey would do in half a second, as J79 would not, so operationally unsafe. Min of Aviation (Industry sponsor) Jenkins claimed commonality, Spey for F-4M, though RAF did not need it.

(Healey, 13/11/65 revisited £100Mn. saving as J79 now seemed acceptable for RN CVs, but Jenkins carried the Case that canx would do “harm to RR's intnl. standing” A.S.Bennell,Def.Pol.&RAF,P.6.9).

(PM H.Wilson, Memoirs,P.78: Spey: our “well-meant decision proved extremely costly to the taxpayer”).

 

[orlovsky]

The case then made to Ministers was that RN's bolter case required slam reheat, which Spey would do in half a second, as J79 would not, so operationally unsafe. Min of Aviation (Industry sponsor) Jenkins claimed commonality, Spey for F-4M, though RAF did not need it.

This is sadly funny. Quoting Caygill, "Phantom from the Cockpit":

"...in the case of a bolter, the F-4K taking about 1,000 ft compared with 300 ft for the F-4J."

"Efforts were also made to ... achieve a [Spey] reheat light up time of 1½ seconds (from 3 seconds)."

 

[alertken]

So, an AH would be: no hot Spey for Phantom, MoA Jenkins failing to keep those jobs in UK.
If we take 1965's package as unchanged, then all RR got was dry Spey in Nimrod.

In actual,. next step was BSEL, having lost BOl.320, cuddling up to Pratt/SNECMA on JT9D, 6/66 after abandoning thoughts of a BS.100-aided UK Big Fan. RR had a Demonstrator RB178 contract. Both of them then pitched for Launch Aid to bid to the US TriJets. MoA had a little think about National Interest: BSEL on 747-winning engine, so well placed for a junior role on lots of TriJets, or RR leading a UK Big Fan, pitching v. 1st. mover. (Schemes to be A300 had RB207/JT9D, but volume of business was expected to be modest: BEAC wanted 6).

RR did Ministers' thinking for them and bought 50% of BSEL,10/66, instantly dumping JT9D.

The money to do that came from Spey 202.

So J79/UK: RR unable to buy BSEL. Ministers might well have taken junior on JT9D as a better bet than most of RR, ah, what?

Now take us, via brief AFVG (BSEL/Bristol on M45G) to, 7/68, MRCA, which was won by RB199, offered from ex-BSEL/Bristol.

Ministers Nationalised RR 2/71, when they messed up RB211, ONLY because they had MRCA.

A credible AH is no RR (1971) Ltd, so today no Brit Big Fan.

 

[zen]

J79 with overspeed was used by Israelis for Mig25 interception efforts. Ramping up to 18,000lb or more at cost of shorter life.
Did J79 use water injection?

If not overspeed and water injection might solve the problem.

Far out AH is RB.106 Thames instead of Spey. Faster throttle responses from a dedicated fighter engine and 15,000lb dry thrust would overcome a lot of issues.

What do we know of BSEL BS.100 fan engine for transports....?

 

[Rule of cool]

Things are becoming a little clearer on the project decision side.

In 1964 or so McD/USG could give a fixed price on the F4B, but not the F4J as it in development. What's more I think it was pretty much well known that the F4B could not operate effectively even on the 199' BS5A waist cats on Eagle and Ark, even with the long nose oleo and drooping ailerons, or bring back unused ordnance onto their small decks.

So the decision was.

1. To spend an unknown amount of money controlling development a version of the Phantom that promised launch speeds of 118-129kts @50,000lbs.
2. To spend an unknown amount of money being a passenger for development of a version of the Phantom that promised launch speeds of 137kts @50,000lbs.

Even in technical terms given the information at the time this is a no brainer.

 

[alertken]

zen #49: BS.123 sampled B.Ol.593 turbine, BS.100 compressor, pitched for MoA' Big Fan Demonstrator, to involve SNECMA.. RR pitched (to be RB178-14, 24,750 lb), evolved from Super-Conway schemes, chosen by MoA 6/65 as the SST was seen as ample BSEL Aid.

 

[BlackBat242]

J79 with overspeed was used by Israelis for Mig25 interception efforts. Ramping up to 18,000lb or more at cost of shorter life.
Did J79 use water injection?

If not overspeed and water injection might solve the problem.

Far out AH is RB.106 Thames instead of Spey. Faster throttle responses from a dedicated fighter engine and 15,000lb dry thrust would overcome a lot of issues.

What do we know of BSEL BS.100 fan engine for transports....?

The F-4Es procured by Israel came with J79-GE-17s - which had a thrust of 11,870 lb dry and 17,900 lb in afterburner.

No, the J79 was not equipped with a water-injection system.

Instead of the Thames, the RR-Allison TF41 could be installed in F-4K/Ms from 1968 on... that "improved Spey" put out 14,500 lb dry in 1968 (USAF A-7Ds) and 15,000 lb in 1969 (USN A-7Es).

Fit a proper afterburner in it and you'll get in the vicinity of 25,000 lb in afterburner (using the same dry:ab ratio as the historic RB168-25 (Mk 201 or 202 Spey).

 

[orlovsky]

Things are becoming a little clearer on the project decision side.

In 1964 or so McD/USG could give a fixed price on the F4B, but not the F4J as it in development. What's more I think it was pretty much well known that the F4B could not operate effectively even on the 199' BS5A waist cats on Eagle and Ark, even with the long nose oleo and drooping ailerons, or bring back unused ordnance onto their small decks.

So the decision was.

1. To spend an unknown amount of money controlling development a version of the Phantom that promised launch speeds of 118-129kts @50,000lbs.
2. To spend an unknown amount of money being a passenger for development of a version of the Phantom that promised launch speeds of 137kts @50,000lbs.

Even in technical terms given the information at the time this is a no brainer.

Yes... with one caveat: The F-4B with the long nose oleo would require around 137 kts @50k lbs, just what the long BS5 + ship speed could deliver.

In this sales document, the nrs for the F-4B are always in mil and for the F-4K in AB. Just a subtle nudge.

The J and K would have a better landing performance, but that could be (and was) retrofitted to the F-4B. With the F-4B being lighter, a further advantage...

 

[Rule of cool]

What about the bleed air? I've read that the blown flaps in the F4K were more powerful and the Spey provided the extra bleed air for this.

 

[Scott Kenny]

What about the bleed air? I've read that the blown flaps in the F4K were more powerful and the Spey provided the extra bleed air for this.

That also caused some challenges for landing. You need high power settings for the bleed air, and if you reduce power you lose bleed air.

 

[Rule of cool]

Does the Spey solve that issue by providing a lot of bleed air at low speeds due to its bigger size?

 

[Scott Kenny]

Does the Spey solve that issue by providing a lot of bleed air at low speeds due to its bigger size?

No, I was quoting complaints about the F-4K.

 

[BlackBat242]

So, an AH would be: no hot Spey for Phantom, MoA Jenkins failing to keep those jobs in UK.
If we take 1965's package as unchanged, then all RR got was dry Spey in Nimrod.

And in Buccaneer S.2.

 

[MadRat]

Being derogatory towards Spey powered Phantoms ignores the fact they had superior power in exactly the flight regime for which they spent their mission. I am surprised J79 was adequate because Spey offered so much additional thrust at launch. But maximum takeoff weight and bring back weight dictate operations, not maximum capability.

 

[Scott Kenny]

Being derogatory towards Spey powered Phantoms ignores the fact they had superior power in exactly the flight regime for which they spent their mission. I am surprised J79 was adequate because Spey offered so much additional thrust at launch. But maximum takeoff weight and bring back weight dictate operations, not maximum capability.

Again, Spey (and the BLC flaps) greatly complicated the landing due to requiring a high power setting when you're trying to keep a specific speed while descending. And if you cut power, you suddenly lose lift and now you're below the glideslope and RAMPSTRIKE!

 

[Rule of cool]

Surely that can't be unique to the Spey? Surely the J79 had low BLC when landing due to low power settings?

 

[Scott Kenny]

Surely that can't be unique to the Spey? Surely the J79 had low BLC when landing due to low power settings?

Yes, for the versions of the F4 that had blown flaps it was an issue, but the US F4s used a lot less blowing overall so it was less visible.

But when trying to land on those postage stamps the RN called Carriers, the F4Ks needed high blowing which meant high power settings.

 

[Rule of cool]

Fair enough, that sounds like a a trade-off. The RN needed the bleed air so has to put up with the trickier power settings.

 

[orlovsky]

I'm not sure about the advantage of this setting...?

The approach speed of the J and K version was essentially the same in the 1964 McD brochure and in the following F-4K manual (left) and F-4J SAC (right):




That came out as expected. But on the single engine approach speed, the hope (left) was for 142 kts @ 33k lbs, reality (right) 150 kts - worse than the F-4B, while the 142 kts should be a good guess for the F-4J's single engine approach speed.

 

[Rule of cool]

With the more powerful blown flaps and the 2 degree greater downward thrust line of the Spey was it more controllable and responsive at the same approach speeds?

 

[orlovsky]

Hmm.... USN F-4K evaluation and follow-up:
"b) Inadequate throttle control so that it was impossible to set up a stable approach path for carrier operations."

"The obvious need for more thrust to address these problems led Rolls-Royce to look towards reducing BLC bleed air flow...."

"Another concern was uncommanded thrust changes of significant size in the full flap approach configuration."
All Caygill, Peter. Phantom from the Cockpit: Flying the Legend (English Edition) (p.46-49). Pen & Sword Books. Kindle-Version.

Some of that was probably corrected, but improvement over the F-4J, I very much doubt that...