Avro Arrow killed in the cradle?

[Lascaris]

Usually you get what-ifs about Arrow not getting cancelled. But arguably the aircraft was too complex, too big and too costly for its long terms prospects. So how about the reverse? Come 1952-53 the Canadians decide to go forth with a less ambitious and presumably more affordable design like the proposed C.104/4. When the lets call CF-104 takes to the air in late 1957 it looks closer in size to Mirage III or Draken with a single engine (what was that supposed to be for C.104/4, I presume RB106?). While no CF-105 it is actually in the right cost performance range to be bought by the Canadians in place of F-104 and F-5 and potentially get some exports as well.

Thoughts?

 

[uk 75]

The elephant in the room is of course the USA.
Arrow was killed by the cheaper alternatives offered by the US (Voodoo and Bomarc).
Your single engined Arrow would be up against the Starfighter and the F106 Delta Dart (or even F102 Daggers).
Mirage and Draken are pretty hard acts to follow. Neither France nor Sweden is likely to change. But Israel and Finland will also stay with M and D.
India was developing its own combat aircraft and Canada might find a partner and customer there.

 

[Apophenia]

The other pachyderm is mission and related range. The C.104 would have been aimed at replacing the Canadair Sabre, the C.105 (like the C.103 before it) was to replace the C.100 Canuck. The Sabre had a shorter-range tactical role (mainly to satisfy RCAF NATO commitments), the Canuck satisified the longer-range NORAD commitment.

 

[zen]

This is also the period of the UK late model Meteors and Javelin. Which is obviously disappointing for any Canadian licensing....

Though there is always the Fighter Canberra option.

And if one wants to throw a wildcard one could ponder Vulcan in some Red Barrel style version.

 

[riggerrob]

Two other variables combined to kill the Avro Arrow: RCAF generals and ICBMs.
First, RCAF generals had lost touch with how much Treasury Board was willing to finance. The RCAF was competing with the RCN and Canadian Army for ever-shrinking procurement dollars. If TB was willing to fund the Arrow, then the RCN would not have gotten any new ships for another decade and the Canadian Army would have been stuck with Sherman Kangaroo armored personnel carriers for another decade. This was also during an era when the RCAF still depended upon CC-119 Flying Box Cars for tactical transports … and they were starting their second or third major overhaul.
Competition between the RCAF, RCN and RA got so viscious that they became greater enemies than the USSR.
I suspect that one of the reasons that Defence Minister Paul Hellyer integrated the Canadian Armed Forces was because he was tired of listening to generals bickering with admirals. When several admirals resigned in protest, that was a relief for politicians.

Secondly, both the USA and USSR were starting to deploy Inter-Continental Ballistic Missiles during the late 1950s. ICBMs flew far too high and far too fast to be intercepted by Arrows.
Arrows were better suited to interfering the TU-95 Bear bombers that wandered too close to Canadian shores. During the 1950s, the USSR was also developing supersonic, long-range bombers.

Given those two factors, Avro of Canada would have been wiser to concentrate on a single-engined, single-seater, supersonic interceptor to rival Dassault’s Mirage III or SAAB’s Drakken.
Forget about competing with CF-104 and it’s tiny wing.

 

[Apophenia]

Forget about competing with CF-104 and it’s tiny wing.

The CF-104 was basically an attempt to replicate the success of the Canadair-built Sabres. And it worked.

The 200 x CL-90s for the RCAF were followed by another 140-odd Canadair-built CL-201 Starfighters for export. The latter were paid for by the US Mutual Aid Program ... while this extra production volume reduced the costs of Canada's CL-90 procurement.

That subsidized export success for the CL-201s also served to support Ottawa's choice of buying stubby-winged interceptors for the NATO low-level nuclear attack role. That may sound bonkers to us but it made perfect sense to Treasury Board and the Conservative Cabinet of the time. And that brings up personalities ...

The MND of the time of the CF-104 procurement was Conservative MP, George Pearkes. Or, to give him his full due: The Hon. MGen G. R. Pearkes, VC, CC, CB, DSO, MC, CD, PC. Montgomery may not have thought too highly of Pearkes' wits during WW2 but no denying that the man had some military game. But, somehow, that never seems to translate into an effective Minister ...

 

[Apophenia]

... When the lets call CF-104 takes to the air in late 1957 it looks closer in size to Mirage III or Draken with a single engine (what was that supposed to be for C.104/4, I presume RB106?). While no CF-105 it is actually in the right cost performance range to be bought by the Canadians in place of F-104 and F-5 and potentially get some exports as well.

I'm not sure about the C.104/4 powerplant. For obvious reasons, Avro Canada hung on to the Orenda TR9s (with Solar reheat) for as long as they could. The early alternative was the AS Sapphire 4 (+ rocket booster). Avro Canada then moved on to a hypothetical 30-inch diameter turbojet.

For the C.104/2, the Rolls Royce R.A.17 (which becomes the R.B.106) is first mentioned in Dec 1952. So, it is possible that the R.B.106 was considered for the C.104/4 (although the Rolls wasn't actually selected for the C.105 until August 1953.

I suspect that both Hawker Siddeley and Avro Canada were fully aware that the C.104/4 was wide of the mark for any RCAF requirement. As an export fighter - even had it received official support - a first flight in late 1957 makes it too late. The Saab Draken prototype had been flying since Oct 1955 and the Dassault Mirage III just over a year later.

 

[riggerrob]

The CF-104 was basically an attempt to replicate the success of the Canadair-built Sabres. And it worked.

The 200 x CL-90s for the RCAF were followed by another 140-odd Canadair-built CL-201 Starfighters for export. The latter were paid for by the US Mutual Aid Program ... while this extra production volume reduced the costs of Canada's CL-90 procurement.

That subsidized export success for the CL-201s also served to support Ottawa's choice of buying stubby-winged interceptors for the NATO low-level nuclear attack role. That may sound bonkers to us but it made perfect sense to Treasury Board and ..

As a poorly-informed, enlisted Air Frame Technician, I had the impression that CF-104s were originally purchased as interceptors and the nuclear bomber role was only “tacked on” after they exhausted all other possible NATO roles.
Mind you, the rumor-mill was pretty “thick” by the time we shipped the last few CF-104s from CFB Baden-Solingen to Turkey in 1985.

 

[Lascaris]

The other pachyderm is mission and related range. The C.104 would have been aimed at replacing the Canadair Sabre, the C.105 (like the C.103 before it) was to replace the C.100 Canuck. The Sabre had a shorter-range tactical role (mainly to satisfy RCAF NATO commitments), the Canuck satisified the longer-range NORAD commitment.

Mission is actually a pretty good question IMO. Deciding to go for a domestic design to replace CF-100 gets you to C.105 and eventually down the path of OTL. So how do you get the RCAF to decide it's interested in a Sabre replacement instead? Perhaps you should go earlier to the develompent of CF-100? Let's say that the CF-100 design avoids the structural error that led the the loss of the secod prototype and the delays of the program. Instead everything goes well CF-100 gets into service somewhat earlier and the earlier entry also gets CF-103 into production in place of CF-100 Mk5 with a CF-103 mk2 firing Sparrow (like the proposed CF-100 mk6) following in service. With CF-103 around C.104 becomes a Sabre replacement...

 

[Apophenia]

Lascaris: I think you are on to something here. The Diefenbaker Cabinet might have played a role there by insisting on a tight timeline (think: modern Danish Defence Agreement incremental funding). So, say, the RCAF has until 31 Dec 1952 to both finalize its long-range interceptor plans and place a production order. At that point, the C.103 and C.104/2 were the only games in town. So, the RCAF must chose between the transonic C.103 or supersonic C.104/2.

A well-advised Cabinet (or MND) might have further stipulated either a C.103 powered by new TR9 turbojets or the more radical C.104/2 powered by proven engines (eg: the Avon R.24Rs for the P.2 Lightning prototype?). Maybe a proven missile type should be demanded as well - keep in mind that the AAM-N-3 Sparrow II never functioned properly (Douglas dumped further development in 1956). A possible alternative (close to being within our timeframe) would be Raytheon's AAM-N-6 Sparrow III (begun 1951, IOS 1958)

The next question is whether Avro Canada had the space or workforce at Malton to built both 'CF-103' interceptors and 'CF-104' fighters. My guess is 'No'. That means, either, transfer production of the 'CF-104' to Canadair or build a second Avro Canada factory outside of Toronto.

riggerrob Yup, I definitely oversimplied the nature of RCAF Starfighters.

 

[uk 75]

What Canada really needed both at home and in Europe was the F4 Phantom.
Twin engined and with Sidewinder/Sparrow.
Rather like the RAF the domestic alternative would be as Phantomlike as possible.

 

[riggerrob]

What Canada really needed both at home and in Europe was the F4 Phantom.
Twin engined and with Sidewinder/Sparrow.
Rather like the RAF the domestic alternative would be as Phantomlike as possible.

OTL the RCAF ended up with the F-4 Phantom’s predecessor, the interceptor-only McDonnel-Douglas F-101 Voodoo. Those USAF-surplus Voodoos “retired” to Canada in exchange for the “loan” of RCAF instructor pilots Voodoos served the RCAF for another 23 years (1961 to 1984) in the air defence role, chasing Tu-95 Bear bombers away from Canadian shores.
While the RCAF might have wanted F-4s, they were too valuable as fighter-bombers during the War In Viet Nam.

 

[uk 75]

Just as the UK had a number of paper Phantom substitutes I am sure Canada could have done the same.

 

[Apophenia]

What Canada really needed both at home and in Europe was the F4 Phantom.
Twin engined and with Sidewinder/Sparrow.
Rather like the RAF the domestic alternative would be as Phantomlike as possible.

Okay, a few things here ...

1: As noted earlier, the Sparrow II never worked and the USN ended their involvement. The Navy may have been wise to do so ... but it left Canadair holding the bag and was a direct contributor to the CF-105 Mk.2 being cancelled. So, USN/RCAF relations may not have been the best in the Spring of 1959.

2: The RCAF's Air Defence Command was integrated into NORAD by 1957. So, by definition, the RCAF was inter-operating with the USAF. Why would DND have been considering a prototype naval fighter in 1959?

3: Assuming that the RCAF was interested in the YF4H-1 in 1959, would production F4H-1s have been made available (and only 45 x F4H-1/F-4A airframes were ever built). USN F-4Bs deliveries didn't begin until 1961 - by which time, as riggerrob has noted, CF-101s were already in service (and under highly favourable conditions, it should be added).

4: AFAIK, not a single Phantom was exported prior to 1968. (I mean, besides the Spey-powered FG.1 naval fighters.)

5: You are proposing that 1 Air Division replace its single-seat, gun-armed, 17,580 lb MTOW Sabre 6 tactical fighter with a 2-seat, missile-armed, 44,600 lb loaded, supersonic carrier fighter. With hindsight, we now know what a great 'land fighter' the F-4 would become. In 1959, this suggestion would have seemed utterly bonkers.

 

[uk 75]

A single seater single engined Arrow meets the same fate just at the hands of the Starfighter instead of the Voodoo/Bomarc for the same reasons.
In real life Canada was keen on the Phantom in the same timescale as the UK. Canadair Phantoms might have equipped both RAFG and CAD in W Germany.

 

[Pioneer]

What about Canada/RCAF working with McDonnell to produce a true multi-role derivative of the F-101 Voodoo? J79-powered (replacing J57), already a two-seat derivative offered (F-101B) and Tactical Recon derivative (RF-101A).
Perhaps, McDonnell appreciate the cutting-edge nature of it's F4H-1(F-4 Phantom II) and it's carrier-based centric design philosophy, see much more merit in promoting an outgrowth of it's 'known' Voodoo.....getting rid of the Aim-4 Falcon's and incorporating two or three recessed Sparrow Aim-7 AAM's from experience off the back with designing and building it's F-4H-1...., wing mounted Aim-9 Sidewinder's....

Just a thought....

Regards
Pioneer

 

[Lascaris]

A single seater single engined Arrow meets the same fate just at the hands of the Starfighter instead of the Voodoo/Bomarc for the same reasons.
In real life Canada was keen on the Phantom in the same timescale as the UK. Canadair Phantoms might have equipped both RAFG and CAD in W Germany.

And why exactly if the Canadian government has to choose between domestic aircraft just entering service of comparable cost to F-104G will choose F-104G over it? To lose the work seats and votes in Canada? If anything this *Arrow would be a contender in NATO against F-104G.

 

[riggerrob]

….. Why would DND have been considering a prototype naval fighter in 1959? ….

Ask the admirals.
If the RCN had maintained their “big ship” attitudes into the 1960s, they would have needed a replacement for the MacDonnell-Douglas Banshee fighters flying from HMCS Bonaventure. As first-generation jet fighters, they were a bit crude. Furthermore, those 39 airframes had been acquired second-hand from the USN, delivered 1955 to 1958. Banshees were becoming increasingly expensive to maintain and they suffered a 30 percent accident rate. The last Banshee retired in 1963.
Finally, few of the new naval jet fighters could land-on the Bonny’s short deck. Trials with the smallest USN jet - A4 Skyhawks - proved that it was possible, but with only tiny margins for error.
So it really depends upon which group of admirals had the most influence. One group wanted to retain fighter jets in the RCN, but with better short deck characteristics than anything the USN was developing.

It was primarily senior officers who maintained “big ship” attitudes since time served as staff officers onboard RN capital ships was what got them promoted to flag status. With only a single capital ship remaining, they saw time served onboard HMCS Bonaventure as the only path to promotion. Meanwhile Parliament was only willing to finance DDE destroyers carrying single helicopters in the convoy-escort anti-submarine role.
Many admirals retired in protest rather than work under this new model.

 

[uk 75]

If Lockheed played nice Canadair would have a chance with a home grown prototype. Unfortunately Starfighter sales were an infamous swamp.
Frankly a single seater Arrow would be like the HS 1121. A beautiful plane but with none of the systems know how of US industry or the financial clout.

 

[uk 75]

Canada was right to go down the destroyers with Sea King (plus some with ASROC) route. The US Navy had enough carriers to tackle long range Soviet airpower but all those reinforcement convoys to Europe needed as many ASW assets as possible against Soviet submarines.
A single small carrier is fine for a nation not expecting to join allies in a major war. Canada was an important NATO navy.

 

[Apophenia]

Ask the admirals...

Quite so. As you've identified, F-4s could not operate from Bonaventure 690 foot flight deck - usually, HMS Ark Royal 804 foot deck is given as the shortest possible surface to operate Phantoms from. Hence those RCN A-4 Skyhawk tests at NAS Norfolk.

So, what if HMCS Bonaventure had survived in service even longer? Well, one possibility would have been to follow the Indian example with another Majestic class carrier - INS Vikrant. She was upgraded a number of times, including a 1979-82 refit with a ski-jump for Sea Harriers.

 

[MadRat]

Canada should have dumped Arrow way sooner and gone SAGE-integrated FF-106 using an Iroquois engine and insisting on Sparrow/Sidewinder support. Hughes was the weak link. Might have even looked at Firestreak/RedTop to spur favorable terms.

Can anyone imagine a Chance Vought XF8U in RCAF service? Room for Iroquois, Sidewinder, and Sparrow all in one package.

 

[GTX]

Can anyone imagine a Chance Vought XF8U in RCAF service?

Like this perhaps?

 

[Apophenia]

Canada should have dumped Arrow way sooner and gone SAGE-integrated FF-106 using an Iroquois engine and insisting on Sparrow/Sidewinder support. Hughes was the weak link. Might have even looked at Firestreak/RedTop to spur favorable terms.

Okay, but what RCAF requirement was this 'CF-106' supposed to satisfy? Could it provide anything (other than Iroquois-related development risk) that the CF-101 didn't have and then some?

 

[riggerrob]

Like this perhaps?

Did F8 Crusader have a sensitive enough radar to work as a long-range, all-weather interceptor?

 

[uk 75]

With the benefit of hindsight Canadair should have found a US type to build and sell itself as it did with the Sabre.
Crusader comes at about the right time. Land based F8s might have been a better fit for NATO than the F104. As a bonus the RAF used Sabres to rescue it from the Swift debacle so Canadair Crusaders might have got it off the Lightning/Sea Vixen replacement hook.

 

[MadRat]

Okay, but what RCAF requirement was this 'CF-106' supposed to satisfy? Could it provide anything (other than Iroquois-related development risk) that the CF-101 didn't have and then some?

You pit contractors against each other to get the desired outcome. There was much more to my suggestion than what was on the surface.

I think the Chance Vought XF8U is being confused with its predecessor. XF8U fighter and F-106A interceptor share motors from the same family as the F-105 fighter bomber. Canada was more than capable of building their own F-106/XF8U. What they needed was a weapon system, which is a supply chain of both weapons and equipment. They didn't have the expertise for that. But the airframe. They were capable of doing a supersonic fighter airframe.

 

[apparition13]

You pit contractors against each other to get the desired outcome. There was much more to my suggestion than what was on the surface.

I think the Chance Vought XF8U is being confused with its predecessor. XF8U fighter and F-106A interceptor share motors from the same family as the F-105 fighter bomber. Canada was more than capable of building their own F-106/XF8U. What they needed was a weapon system, which is a supply chain of both weapons and equipment. They didn't have the expertise for that. But the airframe. They were capable of doing a supersonic fighter airframe.

You're referring to the XF8U-3 Crusader III.

The XF8U-1 aricraft were the original Crusader prototypes, F8U-1 the original production aircraft, and the F8U-2 production aircraft were the Crusader II. It's the pre-1963 naval designation system.

I prefer the Crusader III to the F-106, but there's no way a prototype aircraft is going to be procured. F-106 (with or without Orenda 13) would make sense for the Arrow mission, especially if NORAD integration is a factor.

Was SAGE deployed in Canada as well?

 

[Apophenia]

You pit contractors against each other to get the desired outcome...

Understood.

My question was how buying/building F-106s (or Crusaders) fits into RCAF procurement requirements. Neither aircraft could satisfy AIR-7-3.

 

[Apophenia]

Was SAGE deployed in Canada as well?

Yes, later, on the CF-101B Voodoos.

 

[MadRat]

Understood.

My question was how buying/building F-106s (or Crusaders) fits into RCAF procurement requirements. Neither aircraft could satisfy AIR-7-3.

In the requirement demanding two engines, clearly it would not. But that was fallacious requirements written to a predetermined outcome... I mean political decision.

You're referring to the XF8U-3 Crusader III.

The XF8U-1 aricraft were the original Crusader prototypes, F8U-1 the original production aircraft, and the F8U-2 production aircraft were the Crusader II. It's the pre-1963 naval designation system.

I prefer the Crusader III to the F-106, but there's no way a prototype aircraft is going to be procured. F-106 (with or without Orenda 13) would make sense for the Arrow mission, especially if NORAD integration is a factor.

Was SAGE deployed in Canada as well?

My mistake. Yes, I did leave off the "-3" in that case. While the F-8 was not a bad looking jet, there needed to be a larger radar. And the F-8 might have looked a little funny with an Iroquois engine.

 

[uk 75]

Canada had two distinct requirements in the late 1950s.
In North America fears of large numbers of supersonic Soviet bombers led to the development of long range interceptors (F108, YF 12 A and Arrow) and missiles (Nike, Bomarc). It soon became apparent that apart from modest numbers of Bears and Bison there was to be no Soviet long range supersonic bomber but a family of ICBMs instead. The Voodoo was twin engined with Genie nuclear missiles. It and the nuclear Bomarc were appropriate to the level of threat.
In Europe Canada needed a shorter ranged supersonic fighter with a capacity to strike as well. The licence built F104 made sense as W Germany, Belgium and Netherlands, Denmark and Norway used them. Only France (Mirage) and UK(Lightning/Hunter GA) did not.
Until the appearance of the F4 there was no actual aircraft that could meet both these requirements. In fact it had to wait until the F18 to merge them.
The US in this period introduced the F102 Delta Dagger followed by the F106 Delta Dart but it was only the F101 Voodoo that had the spec Canada needed.
USAF in Europe had the F100 Super Sabre (Denmark, France too) and the F105 Thunderchief coming into service (no other NATO). These served into the 60s until the F4 was bought.
Like the UK Canada could have developed its own F100/F104 equivalent or better yet an F4 alternative.
Sadly the Arrow and the UK 1957 fighters were not these planes.
I suspect neither the UK nor Canada had the industrial and organisational capability to build a weapons system as opposed to a nice looking airframe. TSR2 and P1154 proved this in the UK. Canada learnt the lesson faster with Arrow.
MRCA/Tornado when it came in the late 60s was pretty much an F4 with VG.

 

[GTX]

Did F8 Crusader have a sensitive enough radar to work as a long-range, all-weather interceptor?

Maybe under GCI control

 

[Archibald]

- I hate to say that but RCAF would probably end with F-106s, because NORAD interceptors. Although F-101B might make more sense, because two seats, two engines... and we are back to OTL. Although Phantom is also a match there.

- IMHO the biggest mistake that sunk the Arrow was to dump the MA-1 & Falcons... after 1956 before returning to them by September 1958. Sparrow II was a pipe dream, no way to get even a downrated AMRAAM in the 1950's. It was a fateful 18 months wild goose chase, unfortunately by the era of the Arrow, radars & missiles had became the most costly developments, ahead of Orenda engines and Avro airframe... which were doing well, cost-wise.

-Maybe another mistake came earlier, when they dumped the Avro C-104 delta wing design... which could have been a Canadian a) F-106 or b) Draken or c) Mirage III. Just one engine and delta-wing, seems to have worked well for ADC, France, Sweden. Maybe that was the one and only right way to go ? Only with one Orenda Iroquois it would still have a crapton of thrust. Perhaps hitting the right spot between a smallish Mirage III and a F-106 larger, pure interceptor. Imagine the versatility of the Mirage III but inflated to F-106 size and thrust: could have been a world beater.

 

[Archibald]

Maybe under GCI control

Not that different from all those MiGs and Sukhoi interceptors, post MiG-19 and before MiG-23.

 

[Apophenia]

In the requirement demanding two engines, clearly it would not. But that was fallacious requirements written to a predetermined outcome... I mean political decision.

In what sense was AIR-7-3 a "political decision"? If it had been at all politically driven, the Diefenbaker Cabinet would never have allowed the RCAF to write such a risky and obviously expensive requirement.

Nor do I see what fallacy was involved. The twin-engines of AIR-7-3 were demanded out of concern for potential mechanical failures over largely uninhabited and often hostile territory. Hence the CF-105 programme's replacement by twin-engined CF-101Bs (and, later, the Voodoos' replacement by CF-188s).

 

[Apophenia]

...Maybe another mistake came earlier, when they dumped the Avro C-104 delta wing design... which could have been a Canadian a) F-106 or b) Draken or c) Mirage III. Just one engine and delta-wing, seems to have worked well for ADC, France, Sweden. Maybe that was the one and only right way to go ? Only with one Orenda Iroquois it would still have a crapton of thrust. Perhaps hitting the right spot between a smallish Mirage III and a F-106 larger, pure interceptor. Imagine the versatility of the Mirage III but inflated to F-106 size and thrust: could have been a world beater.

I love the idea of a service C.104 but that too would have likely killed Avro Canada. The Mirage and Draken already had a good lead. Maybe a 'world beater' but the C.104 had already missed its time slot.

Perhaps the money should have been invested in Orenda? Since the Iroquois was roughly the same size as the RB.106, it should have been an easy fit into the Draken (history tells us that Dassault would demand too many Francs to slide an Avon into the Mirage III).

 

[Lascaris]

I love the idea of a service C.104 but that too would have likely killed Avro Canada. The Mirage and Draken already had a good lead. Maybe a 'world beater' but the C.104 had already missed its time slot.

Perhaps the money should have been invested in Orenda? Since the Iroquois was roughly the same size as the RB.106, it should have been an easy fit into the Draken (history tells us that Dassault would demand too many Francs to slide an Avon into the Mirage III).

Marcel would be much more interested to slide an Iroquois into Mirage III arguably particularly in conjunction with the plans to put Iroquois into Mirage IV. If it could be fitted it would be giving Mirage III 19,350 lbf on dry thrust as much as an early Mirage 2000 had on afterburner. And with a lower specific fuel consumption.

Although you are getting into Mirage F3 size territory to properly fit the engine I think, Iroquois is closer to size and weight to TF30 than ATAR it seems to me. Still...

 

[Lascaris]

In what sense was AIR-7-3 a "political decision"? If it had been at all politically driven, the Diefenbaker Cabinet would never have allowed the RCAF to write such a risky and obviously expensive requirement.

Diefenbaker came to power in April 1957. The decisions to develop CF-105 were under the Liberals of St Laurent who were in power since 1948. And you'd better get whatever Avro designs working by April 1957. Which for a presumably simpler one engine aircraft should be feasible.

 

[BlackBat242]

You're referring to the XF8U-3 Crusader III.

The XF8U-1 aricraft were the original Crusader prototypes, F8U-1 the original production aircraft, and the F8U-2 production aircraft were the Crusader II. It's the pre-1963 naval designation system.

To use the later designation system (October 1962 - present):
F8U-1 = F-8A ... AN/APG-30 gun-ranging radar
F8U-1E = F-8B ... AN/APS-67 (very) limited all-weather search & ranging radar
F8U-2 = F-8C ... AN/APS-67 (replaced by the AN/APQ-83 in the early 1960s, improved search&track)
F8U-2N = F-8D ... AN/APQ-83 (added an IR line scanner for night targeting of aircraft {engine heat})
F8U-2NE = F-8E ... AN/APQ-94 (larger diameter nosecone for larger antenna {longer range}, further search & track improvements)

All of these (except the F-8As) eventually saw upgrading from 1967 on to a near-identical standard with more-powerful J57 engine and new radar, added weapons, wing pylons, etc.
-E > -J (also got the boundary-layer control (blown-air) wing of the French Crusaders)
-D > -H
-C > -K
-B > -L
-A > M (planned, cancelled)

F-8E(FN) ... French version, AN/APQ-104 (with modified AN/AWG-4 fire control - compatibility with Matra R530) and boundary-layer control for added lift