F-108 Rapier Question

[jcf]

The weapons load was to be 3 X Gar 9 on a 'rotary launcher' with the missiles 'dropping through belly doors'
when launched. Good luck fitting a fourth round to the merry-go-round.

[rickshaw]

The weapons load was to be 3 X Gar 9 on a 'rotary launcher' with the missiles 'dropping through belly doors'
when launched.

That would have been entertaining to watch at Mach 3.  How did they expect it to get out from the airflow around the opening?  I'd have expected some trapezing launch rails.

[PR19_Kit]

Perhaps they would have fired it out with an extra large charge in the launcher?

[jcf]

Dunno, the base fuselage design had to stretched at one point when the missile
came out longer than first proposed. The main thing is that the XF-108 was always
'a work in progress' right up to the point it was cancelled, and post-cancellation
configuration drawings (NAA kept plugging away at it) show an aircraft with a
completely different forward fuselage and what can best be described as LERX.

Ultimately, it's anybody's guess as to how a production, service aircraft would
have looked and how it would have been arranged internally. Sounds like
Whif material to me.

[KJ_Lesnick]

rickshaw

Too small.  Repost it at a higher resolution, please.

How did it come out that small?

Good to see you doing something other than posting questions, Kendra/Robynn.

Why do you spell my name as Robynn?

[rickshaw]

Considering what Jon has said, I'd say there simply wasn't room in that configuration for an extra missile.  It looks like they are jam-packed in there.  Even providing the missile with folding fins wouldn't provide sufficient room for a fourth in all likelihood.

However, if you were to propose say, a lengthened version with two banks of two missiles, one behind the other, then you could get your wish and carrying a fourth missile, Kendra/Robynn (and why I spell it that way is 'cause that was how I was told it was spelt, if it is incorrect, please advise me of the correct spelling.  Might even be easier if you stopped using a false name...).   

Now, I look forward to your model/drawing/painting/etc.  When will we see it?

[KJ_Lesnick]

Rickshaw

1. It's spelled Robyn

2. Oh well, I figured with the fins removed a fourth could theoretically fit

[KJ_Lesnick]

I'm curious why the F-108 was built around such extreme speed and range requirements

In terms of speed: I don't know what we thought the Russians were truly capable of, but I don't know how many supersonic designs they really had on the drawing boards: I do know of the M-50/M-52 was being developed in the 1950's and it had a top speed that was to exceed Mach 2 if I recall right.  However, the F-108 was to be capable of Mach 4 as it was to use the same engines of the F-108 (which were rated for Mach 4), similar construction (of which Walt Spivak, the chief designer stated airframe and inlets were good to Mach 4).

As for the range: If you operated even from the Northern United States you'd be flying over 3,000 miles to the pole and another 3,000 back: I'm curious as to why (pre-1958) they didn't just take-off from bases in Alaska, Greenland, and the Arctic which we had access to?

[Weaver]

At the time it was widely assumed that the next generation of bombers would be supersonic, with mach 2 ones following not long afterwards. In a nuclear war, the WWII paradigm of shooting some bombers down before they got to the target, some over the target and some more on their way home, just wouldn't cut it any more. In order to avoid a pyrrhic victory, you had to down almost all of them before they got within range of their targets, and the introduction of stand-off missile technologies was pushing that "in range" figure up into the hundreds of miles.

So the challenge was to race out to the furthest possible interception line, engaging some bombers head-on (hence the Genie et all: only way to get the lethal radius bigger than the miss-distance with 1950s tech), and then tail-chasing the rest down as fast as possible before they got to bombing/missile-launching range. That was hard enough with Mach 0.9 bombers, which required Mach 2 fighters to get out to the interception line between "first warning" and "too late" and then overhaul the bombers in a tail chase. Now multiply the speed of the bombers by two....

Of course, building those supersonic bombers proved so difficult that by the time they were becoming possible, ICBMs had arrived, but that's only obvious with the benefit of hindsight. In 1955, no one knew how long it would take to make ICBMs practical, if it was even possible at all.

Ultimately, the difficulties of this air defence situation are why the UK gave up comprehensive air defence and concentrated on defending the V-bomber bases for just long enough to get them on their way: there was no point bankrupting the country to provide an 80% effective defence when the two dozen or so nukes that got through would wipe us off the map anyway.

[jcf]

Robyn, where did you get the idea that the B-70 and the F-108 were to be capable of Mach 4 speeds?
None of the refernces I've seen make such claims. I think you are misinterpreting test data.

[KJ_Lesnick]

Weaver

At the time it was widely assumed that the next generation of bombers would be supersonic, with mach 2 ones following not long afterwards.

Still, a Mach 2 bomber would probably only require an interceptor with a top speed of Mach 2.5 to 3.0 to intercept it: The F-106A fit this profile pretty good actually

In a nuclear war, the WWII paradigm of shooting some bombers down before they got to the target, some over the target and some more on their way home, just wouldn't cut it any more.

Agreed, if you fail to kill the target, there won't be a next time.

In order to avoid a pyrrhic victory, you had to down almost all of them before they got within range of their targets, and the introduction of stand-off missile technologies was pushing that "in range" figure up into the hundreds of miles.

Well, the F4D-1's APQ-50 had a maximum effective range of 200 miles, I assume the F-102A was similar or a little bit greater: Maximum effective and practical weren't the same though and the actual range you'd pick up a bomber-sized target, track it reliably; then get a missile lock were closer in. 

I'm not sure how much technology limited lock-on ranges, but the missiles were a limiting factor.

So the challenge was to race out to the furthest possible interception line, engaging some bombers head-on (hence the Genie et all: only way to get the lethal radius bigger than the miss-distance with 1950s tech)

Well, the Genie was proposed for several purposes

1. Wasting multiple bombers at once: There might have been some people who felt that the USSR would use formations that would be similar to the RAF or USAAF's.  While the RAF's formations were somewhat looser than the USAAF's, they were pretty close from the standpoint of a nuclear blast!

2. If you can't hit accurately enough: Make a big enough bang:  The early missiles had reliability issues and should they fail this would ensure a kill even guidance systems

3. Neutron Kill: It would render most nuclear weapons useless and due to the design of earlier nuclear weapons; there was a worry they'd still go off if armed if the bomber wasn't blown up

That was hard enough with Mach 0.9 bombers, which required Mach 2 fighters to get out to the interception line between "first warning" and "too late" and then overhaul the bombers in a tail chase. Now multiply the speed of the bombers by two....

Actually the F4D was quite effective at intercepting subsonic bombers and it only could do Mach 1.5 if I recall right; the F-102A was capable of probably at least Mach 2 based on the following

• The YF-102 was capable of doing Mach 0.98 max in level flight
  
• The YF-102 could do 812 to 870 mph in a dive or mach 1.23 to 1.32
  
• I do remember (in a rather old book) about the Air Force (1968-1972 about) stating the F-102A was more than twice as fast as the YF-102A: This equates to 1.96 or greater based on level flight speed (most likely), or 2.46 to 2.64 if the speed was more than twice as fast in level flight as the dive speed (less likely based on the fact that the F4D's often seemed to be used for NORAD use and did okay)
  
• While this source is old, the fact is that in those days they would be more likely to under-rate the performance of the planes than modern day; not overrate.
  

The F-106A was considerably faster owing to a more cleaned up fuselage, and variable geometry inlets.  Even those on the F-106 Delta Dart site admitted openly to a top speed of at least Mach 2.5, and made a comment about the vertical tape maxing out at either 2.80 to 2.85

Ultimately, the difficulties of this air defence situation are why the UK gave up comprehensive air defence and concentrated on defending the V-bomber bases for just long enough to get them on their way: there was no point bankrupting the country to provide an 80% effective defence when the two dozen or so nukes that got through would wipe us off the map anyway.

That's why you guys just stuck with the Lightning?


Jon Carr Farelly

Robyn, where did you get the idea that the B-70 and the F-108 were to be capable of Mach 4 speeds?

Several sources of which one includes Steve Pace's book on the XB-70 (Page 6, right half, 2/3 down the page).  It was talking more about Boeing's 804 design, but it stated the X279E engines (J93-GE-1) were rated for Mach 4: While the rest of the book doesn't mention these speeds, it seems as if the author failed to notice the implications of this information.

As for the other sources, one of them was a quote by Walt Spivak, who stated the inlet's and engines were good to Mach 4, though I cannot locate it (It was on one of the few aviation forums I was a member of and got banned -- no it wasn't for asking lots of questions)

[zenrat]

F-102A max speed Mach 1.25 at 40,000 feet.

http://en.wikipedia.org/wiki/Convair_F-102_Delta_Dagger

[PR19_Kit]

Ultimately, the difficulties of this air defence situation are why the UK gave up comprehensive air defence and concentrated on defending the V-bomber bases for just long enough to get them on their way: there was no point bankrupting the country to provide an 80% effective defence when the two dozen or so nukes that got through would wipe us off the map anyway.

That's why you guys just stuck with the Lightning?

That and the fact that we probably couldn't afford anything else anyway...........

[rickshaw]

Ultimately, the difficulties of this air defence situation are why the UK gave up comprehensive air defence and concentrated on defending the V-bomber bases for just long enough to get them on their way: there was no point bankrupting the country to provide an 80% effective defence when the two dozen or so nukes that got through would wipe us off the map anyway.

That's why you guys just stuck with the Lightning?

That and the fact that we probably couldn't afford anything else anyway...........

Or need anything else.  The Lightning provided sufficient of a fig leaf so that HMG could demonstrate to foreign and domestic observers that they were serious about defending UK airspace.  Without that, they believed they would lose the confidence of the electorate and their allies.

Expense isn't something that should be overlooked IMHO.  HMG was having to constantly try and afford a first class defence on a dwindling income.  It had to cut it's sail to suit the cloth and that meant a steadily dwindling armed forces.

[KJ_Lesnick]

rickshaw

Or need anything else.  The Lightning provided sufficient of a fig leaf so that HMG could demonstrate to foreign and domestic observers that they were serious about defending UK airspace.  Without that, they believed they would lose the confidence of the electorate and their allies.

So the Lightning was 20% aimed at defending the UK Airspace, and 80% at showing the UK public that there's something there to defend them; allies that you guys could protect yourself; and of course telling the Russians that you couldn't be easily jumped?