Topic For Discussion

[simmie]

A Grumman  F14 Tomcat powered by Rolls Royce Spey's

Discuss...

[Zen]

Actualy offered I think through RR's American partner Allison.

[Maverick]

Given the F-4s as used by the UK were not the sparkliest performers due to Speys, would this have a major affect on F-14s fitted as such??  I've heard a lot of bad things about the Spey Phantoms is all.

Regards,

Mav

[Zen]

Well on the one hand the F4 troubles where due to engine inlet mismatch (spey needed more airflow) and the changes to the fusilage to get the 2.5 inches increased diameter engine in, which happened to be shorter than a J79 too. The latter causes problems with CoG.

Result of which was the Spey F4 was the heaviest, slowest and most expensive F4 built. It even effected ceiling and range.

So for an alternative to the much more similar in size TF30, those issues should'nt occure.

however Spey is a derivative of a civil engine, and this shows, but RR put a lot of engineering into turning it into a supersonic engine and its low bypass ratio is actualy a blessing for high speeds.

[Captain Canada]

A cat that purrs !

 

[kitnut617]

Result of which was the Spey F4 was the heaviest, slowest and most expensive F4 built. It even effected ceiling and range.

It might not have been the fastest, but it was the quickest.  Meaning it could accelerate quicker, which was handy if it was used as a fleet defence fighter.

[Zen]

The extra thrust and 'blow' told for operations from Ark Royal, giving it the ability to operate with a useful load.
By contrast what I've heard of the J79 F4's that cross decked with the RN was that they where rather marginal, and had to launch at low fuel weights, tanking after launch.

[Archibald]

Easy to imagine!    When the TF-30 definitively proved that it was unreliable (on F-111B and early F-14s) the USN send an untimatum to Grumman : give the F-14 better engines or it will be cancelled.  Fortunately, an alternative existed thanks to Allison. It was an american variant of the Spey, dubbed the TF-41.

This was the Corsair II engine, and Allison quickly grafted a reheat to it. This was mounted on the Tomcat in late 1971.  

[Lawman]

There would be two major options in my opinion:

- Big Spey - i.e. just get the Spey, and as is the norm for civil engines, simply do a bigger version. This could have allowed a 'growth' Spey in the same general category as the TF30 or even F-110, admittedly with higher specific fuel consumption than the latter.

- Another British engine, possibly a new turbofan Olympus replacement, maybe even originally intended as a replacement engine for Concorde? Alternatively, a derivative of the Pegasus, since RR had actually designed much bigger versions for use on other types, not all of them being thrust vectoring engines.

[nev]

Given the F-4s as used by the UK were not the sparkliest performers due to Speys, would this have a major affect on F-14s fitted as such??  I've heard a lot of bad things about the Spey Phantoms is all.

Regards,

Mav

They do get a bad rap, but that's only half the story - they had more thrust at low level than the J79 (and thus were valued on Battle Flight in RAFG), and they were also smokeless.

[Zen]

Prior to '65 the Medway was still a live engine for the HS.681 and was offered in various reheated variants too.

Spey is a scaled down Medway and yes Medway was offered for a number of fighter/strike types as a much more modern engine than the Olympus.

I seem to reccal the Swedes where interested at one stage along with the Olympus OL.22R but wisely settled for a engine already is use albeit a militarised JT8D.

So lawman the engine your looking for is the various Medways RR had on the drawing boards as variants of the hardware they had produced.

[r16]

the Tomcat was an urgent requirement , time was saved by using what was available . USN had huge confidence in the concept and accepted the initial batch only because in due time they would have the proper engines. A foreign engine that would waste time , dry up funds and the congress' patience was the last thing Americans needed.It doesn't matter if the Spey had potential or what.

the engine for the F-14 is the F-110.

not that I have anything against PW.

[simmie]

I happen'd upon this info when I was tralling through a Jane's all World Aircraft

P&W TF-30-414A

Dia- 1293mm (50.9")
L - 5987mm (23507")
W - 1905 KG (4202 lbs)
Rating To/SL 93KN (20,900 lbs st)

RR RB168 Mk202 Spey
Dia - 825mm (32.5")
L - 5204mm (204.9")
W - 1857 KG (4093 lbs)
Rating - dry 5405 KN (12250 lbs st)
         - aug 9102 KN (20515 lbs st)

Hope this helps you all

simmie

[Zen]

That looks wrong, Spey was 37 inches in diameter, its reheat unit about 43 to 44 inches diameter.

Weight of the 202/203 types was around 4,210lb with the reheat section attached.

J79 was around 35 inches in diameter.

Avon I get some off figures, seems some of them where rather fat around the middle at 44.5 inches diameter.

[simmie]

I am sorry if you disagree with the figures that I gave, but they are from Jane's All World Aircraft, so I believe them.