Was the Spey-engined `toom a hot-rod?
 

Reading the Wikipedia entry - it seems to suggest that although there was a considerable amount of modification required, the Spey-engined Phantom exceeded the GE-engined US jet in performance in almost all arenas but flight at altitude.
Is that right?
How did those of you who flew it find it?
Did anyone have a chance to fly both the US engined jet - and the Spey engined jet to compare?
I suspect so - given training requirements - which I assume took place in the US before the first jets were delivered?
Would be very interesting to hear some stories...

Plenty over here flew both - 74 Sqn's post-Falklands aircraft were ex US Navy F4Js.

I read in a book somewhere that the Brit Tooms were more expensive and underpowered, compared the American engined examples.

Underpowered? No...

Spey - 12,250lbs dry, 20,515lbs reheat
J79 (GE-17) - 11,900lbs dry, 17,900lbs reheat

Unfortunately, the fuselage mods to allow the Spey to fit (wider intakes needed for increased mass air flow, deeper and wider rear fuselage) ruined the area ruling and increased drag to such an extent that much of the expected benefits of the increased thrust of the Spey were lost.

-RP

I only flew the FGR2 / F4M, but it was no slouch. In RAFG LLAD fit (2 bags + gunpod), we made 1.6M at 36K on one high level intercept as fighter; my WSO was not a happy bunny, as it screwed his final turn keys.

At LL in the above config, she was superb, with awesome acceleration. With tanks and gunpod removed she was brutally powerful. On a windy winter's day, I recall being airborne just past the app end cable, after an 8 second ground roll; this just about matches the Tiff!

In my book she was a great fighter.

Like 27mm, I was an FG1/FGR2 man, but I remember that we did a number of mixed type trips from Wattisham and our FGR2s had a job keeping up with the 74 Sqn aircraft.

In McDonnell flight test in 1967, our tired F-4C chase plane had no problem keeping up with the first F-4K during acceleration at altitude. We (and Rolls-Royce) were relieved when it finally reached Mach 2. The Brits blamed the shortcoming on airframe drag and McAir, less than spec thrust. Performance may have improved subsequently.

It may have been Gunston or Roy Braybrook who wrote that "nobody realized how much supersonic thrust the J79 could put out, until they put the Spey in the F-4".

The Spey did have very good thrust at low level but the reheat light-up time was quite slow (about 5 seconds from memory). I flew one trial in 'C' fit when we had tests at 750 KIAS (the limit)and 250 ft (over the sea) and thrust was not a problem. I only flew a few sorties with the J79 and didn't have the chance to go high speed low level so cannot comment on the difference.

At Boscombe we had the pre-series F-4K (XT597) which we often flew clean (plus AIM7 on station 6 for c.g. reasons) and it was quite light so the opportunity was taken to try to get a Spey-engined F-4 to 2.0M. The profile we used was to climb to 48 000 ft at 0.95M then enter a shallow dive to accelerate until you reached 2.0M. The first time I tried it the rate of climb seemed quite low above 40 000 ft so I started the dive before early (cannot remember precisely how high) and I only reached 1.95M. The next time I persevered to 48 000 ft and reached 2.0M quite easily. We had a couple of very experienced F4 guys on the squadron and they had never been to 2.0M in a Spey-engined aircraft until they flew 597. Again, I never had the opportunity to fly this profile in a J79 mark so cannot compare although the high altitude flying that I did in one I recall as being much better performance qualitatively. The only other interesting performance point in a 'clean' 597 was 600 KIAS at low level, pull into a vertical climb and zoom until about 250 KIAS then pull over at 5 - 10 AOA until inverted and roll out; used to make about 31 000 ft. Happy days!

Clean aircraft generate impressive numbers, those in war-fighting don't.

I recall the 20 Sqn Hunters from Tengah, going to to Seletar for a major service. There was a roster! Tanks, pylons and, IIRC, even the Sabrinas were taken off. A clean Mk 9 ... Anyone here with a 20 minute trip in a stripped-down Hunter before fuel became a bit 'interesting'? :)

I was 20 Sqn's ATCO, so they told me these things. I only ever got to fly in the NoMotion Sim ... dammit :)

I imagine the Spey, designed for the Bucc with a small by-pass, was optimised for low levels. More thrust off the boat and better range at all levels, but less thrust at high level (a trait the F3 inherited) - and also for the drag reasons highlighted above. I guess the J79, like many US engines would have had much quicker response and been better at high level.

I've flown in a couple of US-engined jets, including a German F4 once, and I seem to remember the rpm gauge seemed to be connected directly to the throttle - unlike the laggy response of UK high by pass jets.

Of course I should have said slower, thanks for that Rhino. I take it from your moniker, you're a fan of the Mighty Toom as well.

'fan', might be considered something of an understatement, 'obsessive' is probably closer to the truth... ;)

-RP

Phantom Spey
 

One aspect where the Spey was outperformed by the J79 was the reheat nozzle design. The translating shroud on the Spey had a large base area behind the inner petals so even when the nozzle was fully open in max reheat there was still a lot of base drag. There was talk of a true convergent/divergent nozzle being designed for the Spey but as far as I know it never materialised.

I recently re-read Sir Stanley Hooker's autobiography Not Much of an Engineer. In one chapter he describes his experiences when Rolls Royce sold the Spey 202 design to the Chinese. In the mid 1970's we (HSA Ltd) hosted a visit to Holme on Spalding Moor by a combined Rolls Royce and Chinese delegation. We had been told they could see any aspect of the engine and it's installation in a UK Phantom but not view the radar or look in the cockpit. I expected lots of detailed questions about the clever bits of the installation such as the intake ramps and bell-mouth. In fact the thing that seemed to excite the Chinese the most were the little spring-loaded fingers that sealed the gap between the rear fuselage and the translating reheat shroud. I have occasionally wondered how they got on with the reheated Spey and whether they are still in service.

Walbut

F4k/M v F4j(UK)
 

Having spent 15 years flying both, one snippet might help. The Avengers, flying F5s reckoned that when they did a head-on pass against an F4K/M it had accelerated out of Sidewinder range by the time it was in their gunsight, unlike the J79 F4, which was still in range.

Let me add the supersonic test profile of the German J- 79 RF-4E, clean aircraft.
We climbed to 36.000 ft , selected reheat and accelerated through mach1 in a slight dive, regained FL 360 and accelerated level to check at least M2.2 as max speed , which some jets exceeded up to M 2.35. To reduce to subsonic speed the power had to be reduced to minimum reheat ( deselecting reheat could have blown the nozzle flaps), spedbrakes were extended and a zoom climb to 48.000 feet initiated. AFAIK the German J-79 F-4F was doing the same profile, but was slower in top speed.

License built copies of the Spey 202 (Xian WS-9) are still in service and power the Xian JH-7/7A...

-RP

The Chinese had a lot of trouble producing the Spey 202 as the WS9.

Even though it was under licence production from RR, they didn't have the level of technology for - at that stage - such an advanced afterburnered bypass. A main problem, I believe, was mastering turbine blade technology.

So in a game of catch-up there was a lot of reverse-engineering, and in the late 1990s China bought over 100 ex-RAF F-4 Speys. These powered the initial limited batch productions of the JH-7 (FB-7).


Finally they cracked it with the indigenous WS9A which has powered the follow-on JH-7A. China has truly benefited from the technology transfer.

A very good read on the early problems with the Spey engined F4 is 'Fly no more' by Brian Davies.

Scan2334%255B5%255D.jpg (image)

Would be interested to know if the Spey fit contributed to wing crack issues on the K & M.