Supermarine Scimitar

[Howard of Effingham]

please, please oh! pretty, pretty please could we have a supermarine scimitar.

i have not the £$£$ or the patience for a 1/48 vacform and the frog 1/72 offering
is just too hard to find and i declined a battered 1/72 one at the 2004 SMW.

i have plans for RAF scimitar FA2's and a FRS3 in falklands era markings, never
mind the markings they did actually carry.

trevor

[Thorvic]

Trev

Already done by Czechmaster a few years ago in resin, so no way Colin would try and match it for the same cost !.

1/72 Scimitar Kit

Cheers

Geoff

[Howard of Effingham]

Already done by Czechmaster a few years ago in resin, so no way Colin would try and match it for the same cost !.

1/72 Scimitar Kit

thanks thorvic.

and you too lee.

£29.80 is ok ish for me, but i would prefer limited run injection moulded as that's
easier to kitbash with.  ^_^  

[ysi_maniac]

I do remember some styrene injected Scimitars: in 1/600 Ark Royal by Airfix.

Sorry, I could not resist. But it is true, no?  

[Geoff]

Welsh Models do a 1/144th vac form one with white metal "bits".

[elmayerle]

Magna also do a Scimitar.  Not as good as the CMK one but probably cheaper.

If you can find someone willing to part with an example, Skybirds-86 did one.  ISTR that he had some nasty comments about the Magna one being a copy of his when it came out.

[Zen]

Real world.
Circa July 1953 NA.38 was changed, it would now require a heavier aircraft, to operate from Fleet carriers with 151ft BS mk4 catapults. Launchable in 15kts WOD, recoverable with mk 13 gear at no more than 28kts WOD.

CAP endurance 2 hours.
Climb 12,000ft/min
Speed at sea level requirement still at 600kts, but 530kts at 40,000ft.
Ceiling without missiles to be 48,000ft or above.
Desired armament two Blue Jay (Firestreak), four 30mm ADEN, or alternatively four Blue Jay and two 30mm ADEN.
Future development to take two Red Dean AAM's or two Red Angel rockets.
Use of AI.18 radar and mk2 GCS Blind Predicting Gunsight.

Met by Supermarine Type 556, a development of the Scimitar, with widend forward fusilage to take the 30 inch AI.18 and side by side seating for pilot and radar operator. USe of reheated Avon RA24Rs.
Climb was predicted at 43,600ft/min.
Sea level speed maximum at 665kts, and 600kts at 40,000ft.
Maximum take off weight for long range fighter with two 30mm cannon, two Blue Jay, two Drop tanks is 41,852lb.
Single prototype was ordered September 23 1954, allocated number XH451.
Mockup suspended April 27 1955. Not enough money to persue two fighters, this being concurrent with the DH110 Sea Vixen.

What happens if this project is continued instead of the DH110?

Likely the following remains true.
Red Dean is dropped, and illuminator issues with AI.18 make the successor AAM, Red Hebe unlikely to continue post 1957.
So the machine might never progress beyond the AI.18/Red Top system. But its likely the option with four AAMs and two cannon is favoured. Cannon may be dropped in favour of microcell rockets.
However we know that a developed AI Pulse Doppler was offered to upgrade the SeaVixen in 1966 (this maybe called AI.25 and it may relate to SeaSpray), and this may relate to Ferranti's PD seeker head offered for a radar guided version of Red Top (this to also use a new MAFI/RFNA rocket motor for IOC by 1968).

Could this be part of an upgrade package for the Type 556?

However it might be that this machine reduces the pressure to find a replacement compared to the SeaVixen, which might suggest the earlier Aspinal CW set inteded for the RN along with a new AAM (AST.1193) is considered as a upgrade for the aircraft to meet AW.406.

But even earlier in 1958 there was talk of an improved AI.18 set that would cure the illuminator integration issues.
Would a push have been made at this time to get the "lightweight" developed AI.18 working?
In which case assumably the radar guided missile would still be live at this stage, but which one?
The Vickers Small Weapon, a scaled Red Hebe down to 670lb, 9ft long, 10" diameter, with a x-band seeker?
Or the Fairey Semi-active Radar Weapon, a sort of scaled up Fireflash (bluesky) dart in appearance, 500lb, 10ft 11" long, 12" diameter J-band seeker?

Supermarine may offer thinner (but of greater span) outer wings but whether their chosen is another matter, this formed part of the Type 558 mark 2 Scimitar offering of April 1955. Its quite reasonable to see the full leading and trailing edge blown reducing TO and L speeds by another 9kts or so.

Prior to 1957 there maybe an option to fit the RB.106 "Thames" engine in place of the Avons, but probably retaining the limited reheat units of the former as the larger units diameter would require too great a set of changes to the aircraft.
Climb performance would be higher, since each RB.106 produces about 15,000lb of dry thrust. Acceleration would be better, but going supersonic would require the use of reheat. However once over the 'hump' and into the supersonic regime, the real differences between the Avon and the Thames would show in markedly improved performance.

Post 1957, there maybe a number of paper engines offered, but by the early 1960's the talk would be of the Spey, however the limited diameter reheat issue would remain. Use of Spey should increase endurance, but the engines will be heavier than orriginaly offered if supersonic flight is required.

IT should be noted this gives the RN experience of the use of reheat on their carriers in the early 1960's something which otherwise does'nt happen until the introduction of the F4.

Talk of using one or more rocket motors might be bandied around, but whether this goes beyond drawings prior to the whole rocket motor boost idea being dropped around 1960 is questionable.

Its unlikely a replacement would be chosen in 1964, rather simply development probably opted for in 1963, but what does this do to the eventual requirement to replace it and when?

IT should be noted this aircraft does'nt require something as large as CVA-01, and should operate reasonably well off Victorious and even Hermes.

[Tornado]

Good post Zen. Certainly something to think about here.

I would think any service Type 556 would have to have the blown leading and trailing edges from the start and this would be relatively easy to acheive, the thinner wings would be out unless a proper Mk.2 is brought as new-builds rather than just equipment upgrades.

Would not Blue Dolphin be the better radar guided AAM? Easier to ship a missile already based on the IR guided one. Airframe clearances and weights are much the same and the hardpoints don't need fiddling about with. From previous attempts the Vickers Small Weapon and the Fairey Semi-active Radar Weapon seem likely to be duds anyway. The rumoured AI.25 seems to be the best bet if Labour can be forced to squeeze out some more pennies to afford it and some kind of radar-guided Firestreak. The guns would be dropped quite soon I think and Mircocell inserted or extra electronic equipment stuffed in.

The chances of the RB.106 being fitted is slim unless the RAF buys it for one of their fighters, costs alone would rule this out. Spey is the only engine available in the timeframe and the likely costs, an afterburner is a must. Maybe then with the experience of the Spey the government doesn't insist it be put into the F-4 and therefore save even more money in the long-run. With the thinner outer wings the spey might just be good enough. The F-4 is likely the only replacement option left for 1969-71 timeframe unless a Spey-engined F-8 is brought instead which is unlikely given the capability loss over the Type 556 unless its a two-seater.

Also for the Mk.2 proabably some kind of TSR.2 based interial navigation system might be fitted for accurate navigation and maybe a possible secondary-strike role.

[Zen]

Its probably true to say the FAW mk1 Scimitar would enter service without guns rather like the SeaVixen did.

Service entry would be 1958-60, and likely the second batch will gain the fully blown wing.

The curious thought you see is that all the aircraft that might gain the RB.106 or its scaled up version the RB.122 where canceled in 1957, and thus RR abandoned the effort. But if the FAW Scimitar is there entering service RR might just continue with it for future orders.

Similar can be said of the radar guided missile efforts, all the machines bar one where killed off that would use it, and the one that survives (Sea Vixen) is clearly going to be replaced soon.

I would'nt say the late radar missiles of the late 50's are duds, rather their more likely to succeed, since both teams know a hell of a lot more about actualy doing this by then. Of the two Faireys design seems more rational.
Radar Red Top is still going to be a limited weapon, for this era which predates the improvements in rocket motors and seeker heads.
AI.18 seems a problem, but it also seems solutions where on the way when the radar missile is dropped at this time. I'm not entirely sure how much was changed on the SeaVixen FAW mk2 to mate it with Red Top and I suspect the minimum rather than the full capability expected of the 'new' AI.18 sets, which likely remained on the bench as far as hardware goes.
Change the circumstances and its likely this AI.18 set would be persued with more vigour.

The reheat issue is not an issue, merely the size of the reheat unit, and as I said this Scimitar cannot have the large diameter reheat units, so reheat is there on the machine just not as powerful as say the Spey 202 or the RB106 types at around 21,000lb, but closer to something like 16,000lb.
For the RB.106 its main advantage is to push the machine over the hump to supersonic flight at altitude. But its more useful generaly for the Spey.

So a mk2 would see a change of engine, and maybe the Aspinal CW set both to enter service around 1972. This would have to come with a new missile not Red Top, either from HSD or BAC.

SO
Scimitar FAW mk1 = Twin Avon RA24R, microcell rocket pack, four Firestreak AAMs or two radar missiles mated with the AI.18, IOC 1959 say, FOC 1962.
RN orders roughly 60 aircraft.
Mk2 = the return of a single 30mm ADEN, AI.26 CW (Aspinal) set mated with either Red Card (BAC John Forbat missile) or Red Kite (HSD Family 500lb) and Taildog, Spey engines IOC 1972, FOC 1975.
RN orders some additional aircraft and some conversions of the mk1 to mk2 standard.
Integration with Martel might be on the cards.

Successor aircraft would thus be the MRCA. Or the new 'Fighter' studies that began as a Jaguar replacement...leading to the Eurofighter today

IF the RAF want this machine the question is what for? Its not a OR.356 type by any means, so they'd need to write a spec for a radar missile toting fighter, but that is possible in the 1960 timeframe, as an adjunct to the Lightning to replace the Javelin more effectively.

[Tornado]

Hi Zen,

I'd thought I'd restart this thread as I have just read Aeroplane's monthly techinical feature which features the Scimitar this month. Also I'm reading a book on Vulcans and an idea popped into my head and I'd like your opinion if its a feasible idea.

The Ecko AI.20 Green Willow X-band radar was developed as a stand-by incase the AI.23 was a dud and eventually this radar became the lightweight Red Steer for the V-bomber fleet as a rear-facing warning radar. It was a basic system but my idea is that rather than build an AI.18 equipped Scimitar, which overlaps the Sea Vixen, why not fit AI.20 into the nose to give a better all-weather capability. Given the timeframe such fighters may have been new-builds rather than conversions. With Firestreak or Sidewinder IR guided AAMs replacing most, if not all, the ADENs then this gives a FAA a basic day fighter with more chances of intcepting a target as a backup to the Sea Vixen. Its cheap and cheerful but might have been all that could have been managed in the financial conditions at the time.

Now would AI.20 fit in the nose without major redesign?
Would the AI.23 be a better choice?

[Zen]

Well the prototypes where fitted into the Swift F7 and used for the beam rider missile Fireflash.
This means the set was able to provide a beam that could be used for illumination as much as beam riding.
The prototype sets produced a beam only fxed to the aircrafts axis...fine if your targeting a big bomber about 2.5miles astern it.
Not sure this radar ever was mated with Firestreak, nor am I sure how easy that would be, since it would need to slew the seeker head to the target and I'm not sure how well the set gave out the sort of signal to do so.

The use CW rather than pulsed beam was felt to be more useful at low and medium altitudes. Pulsed doppler was felt of more use for dealing with high flying fast moving aircraft.

Detection of a hunter sized fighter was I think 5nm and a bomber at 7nm, this using the small dish which maybe less than 24inches diameter.

So in theory contined development to the full AI.20 would see several options open.
1. with the NA.38 (Scimitar FAW) machine this could be taken to a 30inch dish and presumably detection of aircraft pushed out by quite some degree. This would match with an increase in power output.
2. If the electronics for keeping the beam on a target can be squeezed into a set, then SARH missiles become possible.
The electronics need to keep the target inside a certain circle dependant on range, closer the target the smaller the circle as the Beam was very narrow obviously.

3. the existing set with some refinement could certainly fit the Scimitar F.1

Being x-band the set is a possible match for the Red Hebe, and Vickers Small Radar Weapon, but Fairey who worked with this for Fireflash moved onto J-band illumination for their sketch of a new missile (looking rather like a scaled up Fireflash dart).

Later X-band sets derived from this work where used for Concord I think, as a weather radar and at 30 inches had quit some range for surface targets, if a little hazy of course. Theres footage of a set showing ships in the Med south of Sadinia, while flying over I think Libya or Tunisia.

This link will help
http://www.ekco-radar.co.uk/poole/ai20.php

[Tornado]

Thanks for the additional info Zen,

It seems I was not so crazy after all!

It would seem a 30 inch dish improved set could have been created and fitted and would have given the Scimitar a better aerial and surface search capability. Even the refined AI.20 with the 24 inch dish would have given a good capability agianst bombers (I'm thinking possible Tu-95 and Tu-16 bombers over the North Atlantic).

Armament poses questions. Of course Fireflash was not a huge success and was very 'draggy' so is not really an option for a 1956-57 timeframe. Red Hebe is too big, it would affect performance too much, also Red Hebe was designed for launch from supersonic fighters (M2.5), something the Scimitar was not. The smaller Vickers Small Weapon would have been a better choice. Certainly Squadron Leader Poole, (radar and ECM specialist with Operational Requirements branch) felt Red Hebe was a generation behind the American developments taking place. I'm still sceptical myself, if Sandys hadn't axed red Hebe it still would have been a technical failure compared to more modern designs.
Blue Jay Mk.5 (later Blue Dolphin) might be the best option if the AI.20 could accomodate a compatible CW illuminator. Maybe a mix of missiles with Blue Dolphin for lower-altitude targets and Red Top for higher altitude targets?

Much of this is pure what-if but I wonder if anyone in the MoS or the Admiralty did ever consider an AI.20 equipped Scimitar at any time?

[Zen]

Fairey's proposed Semi-Active Radar Weapon was its contender to the same spec as Red Hebe and the VSW. It looks like the unpowered dart that forms the heart of Fireflash, in otherwords less draggy due to the motor being integral rather than a pair of boosters.

Seems Vickers also appreciated the issues with seekers, both Vickers and Fairey seem to be moving towards monopulse seekers, and J-band would match that AND the AI.23, while X-band meant either a new set or the choice between AI.20 or AI.18.

Use of the older mechanical X-band seeker meant the distance at which you could guarentee the weapons closeness to the target pushed up the size of the warhead. Thus the size and weight of Red Hebe.
Vickers stated a move to J or I band monopulse seekers would reduce weight from 1,350lb to 950lb for Red Hebe.

Faireys weapon was proposed with a continious rod warhead which improves lethality compared to more traditional warheads as Vickers was using at the time. Their missile was aimed at about 500lb total weight but it was more sketchy.
Of the two it seems Fairey where on the right track, but not supported, despite having the more practical experience of radar guided weapons on aircraft after the Fireflash effort. No surprise as Vickers was always favoured....too much 'old school tie' going on there. Thus the preference for EE over Fairey that lead to the Lightning being ordered.

DH's Blue Dolphin would be an option, and with a CW x-band seeker, compatable with the AI.20, and DH had more pull with government ministers, though it was fading after the delays over the DH110 and the whole Commet saga.
At the time CW was considered a better option for dealing with low flying aircraft, and since the concern was high flying aircraft IR looked the better option (hot objects up high get very visible when your looking up at them).

I think the prototypes used on the Swift where 18 inches diameter, this comes from a comparable drawing of the proposed Hunter with the same missile/radar combination (based on wingspan being the same). AI.20 would take this to at least 24inches.

Its inverse square law for power over distance. That is to double a signals strength for a given distance or double the distance for the same strength you have to quadruple the power.
Similarly with reception. To double the gathering area of a dish you need to quadruple the dish area.

Signal of a search beam must go out to target AND THEN BACK. This means to double the return signal strength or get the same for double the distance you must octople the power!

But electronics improved sensitivity to existing signal returns, thus the 'memory' mentioned at the ECKO website history of the prototype radar. UK seems to lag behind the US in this field, at least for lightweight sets used on aircraft. At this time a lot of stuff is very analogue, getting digital compact enough and light enough was extremely expensive. Read the section that covers a single high power transistor used in the prototypes.

AI.20 does seem to be considered for the Saro P.177 fighter, but oddly the Scimitar proposals either have AI.18 or AI.23, never AI.20.

[Zen]

If you've got the developed Scimitar, then there's no need for Phantom?

Indeed, no need for the F4 for at least the 60's.
Scimitar FAW would enter service around the year 1960, and should be a valid system into the 1970's.

So the Scimitar FAW would likely fill most of the roles for the F4 in both RN and RAF service.

Possibly if the strike/attack variant of the FAW is persued but that puts the RN in a difficult position vis-a-vis the Buccanner.
RAF certainly started life with the F4 as a strike/attack machine, only later switching it to Fighter duties, once the Jaguar came into service. So some variant of the Scimitar does seem to have its attractions as a earlier way of getting tactical nuclear strike into the RAF.

[Tornado]

I'd love to see an RAF Scimitar.

However it seems the RAF would not accept any Navy aircraft but the latter was forced to use a series of RAF aircraft re-hashed for carrier use (Sea Venom etc). If the RAF wanted TSR.2 over the Buccaneer, even with improvements at any cost then I doubt they would have accepted the Scimitar even as a stop-gap, maybe not even with improved supersonic versions (which would take longer to get into service anyway).

Let's say the Navy had a AI.20 equipped Scimitar FAW.1 from 1956-57 and then your proposed Supersonic Scimitar FAW.2 from 1960-61 and this meant the Navy had no need of the F-4 what would the P.1154 programme look like? Would the RAF go it alone and develop its own variant or would Healy force the RAF to buy the F-4 anyway?