LRAPIS - 1960 hypersonic successor to LRI-X?

[patburke06]

I heard rumors about and little bits of info on successors to the LRI-X interceptors that were hypersonic and had missiles with a range of 500 miles is there any info on them like blueprints and performance information?

 

[hesham]

Welcome aboard Patburke06,

strange Info for me, all I know about developments for LRI ?.

 

[patburke06]

LRAPIS is the successor programs name if I’m correct and can someone can find any info other than Mach 5, and 200 mile high service ceiling

 

[Grey Havoc]

From an old SPF thread that you may have already seen:

Following disillusionment with the F-I08, ADC began, in October 1960, to work on the specifications for another advanced long-range manned interceptor (involving what ADC described as a "quantum jump" in interceptor performance) designed to cope with a new family of threats that not even the F-I08 could be expected to handle. These new threats included air-launched ballistic missiles (ALBM), submarine-launched ballistic missiles (SLBM), Boost Glide Vehicles and Intercontinental Cruise Missiles (ICCM). This advanced interceptor was initially known as LRAPIS, for Long Range Advanced Piloted Interceptor System. The ADC Plans organization estimated that this aircraft would have to be capable of a speed of Mach 5 and an altitude of 200 miles. Asked for an unofficial opinion on such a vehicle, WADD agreed that development of the LRAPIS was technically feasible, but that the difficulties would be great. In the first place, WADD didn't believe it could be developed by the target date of 1966, but that 1970-72 would be more logical. Furthermore, it would have to be extremely large (about the size of a B-70), which would probably limit its use as a fast-reaction interceptor. Finally, the cost was likely to be astronomical. Despite this somewhat negative response, ADC continued to feel a need for a long-range manned interceptor beyond the F-101B. As of the summer of 1962, the LRAPIS had evolved into the Improved Manned Interceptor (IMI). USAF and DOD had expressed interest in such a vehicle, but approval for development had not yet been received .

Note that, according to a late 1970s USAF historical document, the supposed 'disillusionment' was actually a cover story; the USAF was actually quite pleased with the way work on the F-108 had been going, but in the late 1950s the Air Force suffered a major funding crisis that was apparently (according to later historical revelations in the 1990s and beyond) at least in part down to cost overruns on the Minuteman ICBM (in an ironic echo of the Navy with it's Polaris SLBM program if only the two rival services had but known it). The Rapier was unfortunately one of those programs that was (rather ill-advisedly at best) sacrificed in order to plug the funding gap while trying to conceal the truth from Congress (and the ICBM program's own enemies in-house!).

 

[Antonio]

Mach 5, and 200 mile high service ceiling

Never heard about that project but that figures you give are quite high, especially the service ceiling which is just into the Low Earth Orbit. The F108 estimated ceiling was 15 mile. Are we talking about kind of space plane instead a bomber interceptor? A bomber capable of 200 mile service ceiling was also beyond capabilities of Soviet Industry in the 60's. The Mach 6 Tu-360 from the 80's had an estimated ceiling of 18 mile.

Could you please give a source for that "LRAPIS" program?

 

[Antonio]

Could you please give a source for that "LRAPIS" program?

Many thanks Grey Havoc.

 

[Grey Havoc]

An edited excerpt from a late 1964 USAF historical document (an ADC in-house historical study) that may have deliberate or inadvertent inaccuracies and omissions given the period it was published:

The Wright Air Development Division of ARDC admitted that the LRAPIS was technically feasible, but that the technical difficulties would be great and the cost would be fantastic.49

In view of the ARDC comment, ADC, in early 1961, scaled down the LRAPIS to a vehicle capable of speed of Mach 4.5 and an altitude of 90,000 feet. A formal Qualitative Operational Requirement (QOR) on this subject was submitted to USAF in April 1961, but generated no enthusiasm there. It had neither been approved nor disapproved by the end of 1961. Meanwhile. in the summer of 1961, ADC was invited to participate in planning a new, all-weather, joint-service 2.5 Mach aircraft called TFX. But ADC demurred on the ground that a Mach 2.5 interceptor would be too slow to counter the post-1965 threat. Also, ADC felt it needed an aircraft with a radius of action of at least 800 miles. In August 1961 USAF entered the discussion by presenting the Department of Defense with a proposal to provide 25 squadrons of long-range interceptors to ADC, beginning in Fiscal 1967. DOD disapproved the USAF request, but USAF hoped approval would come later, with funds to be made available in the with funds to be made available in the budget for Fiscal 1963. USAF had in mind an aircraft that offered performance somewhere between that of the F-108 and LRAPIS.50

But no funds were requested for what had come to be known as the Improved Manned Interceptor (IMI) in the budget for Fiscal 1963. In something of an afterthought to his testimony before the Senate Armed Services Committee on 22 January 1962, Secretary of Defense Robert S. McNamara said that "later on, if a new inteceptor is required we could consider the TFX fighter for that role.51 The TFX, of course, was not what ADC and USAF wanted.

Even so, USAF indicated to ADC in January 1962 that DOD recognized the need to modernize the interceptor fleet after 1965. At the same time, USAF did not believe it was an opportune moment to push LAAPIS Nothing much happened, however, as the months stretched into years. Hopes were rekindled when Secretary McNamara visited ADC/NORAD on 14 August 1962 and appeared to listen sympathetically to briefings which detailed the requirement for the IMI. He asked for a further briefing on the subject in Washington on 5 September.

I'll add a bit more from that document later since I have to head away in a few minutes. Note that 'USAF' in the text refers to USAF Headquarters and the Department of the Air Force.

I didn't include the referenced notes because, between redactions and poor document quality, not to mention a fair bit of slightly cryptic shorthand in some of them, they are not very scannable. I might try to add them in a later edit though, I'll see.

 

[cactus]

Hello! This is my first post so I’m sorry if I didn’t clean up the document enough.

An expert from NORAD / CONRAD Historical Summary January- June page 50

The Advanced Piloted Interceptor in mention is LRAPIS

Advanced Piloted Interceptor. ADC wanted it to be capable of operating at 100,000 feet altitude at Mach 5 speed, possess a range of 1500 nautical miles, and be able to make three kills with a 500-mile missile against all post-1966 threats except the IRBM and ICBM. The operational date was to be no later than 1966.

In its reply, NORAD posed a series of questions which, in essence, wondered if the proposed interceptor were not too complex to meet the imminent threat of the supersonic bomber. Any realistic proposal for solving the problem would receive NORAD's heartiest blessing and support. But this particular design did not seem
to fit the bill.

In the light of NORAD's comments, USAF ADC modified its QOR, lowering the speed and operating altitude to Mach 4.5 and 90,000 feet, and including more detailed information on the concept of employment. In April 1961, USAF ADC sent the QOR to USAF for study and action. At the same time, it asked NORAD to submit its comments on this revised version for forwarding to USAF.

These were furnished by NORAD on 31 May. While agreeing that the post-1966 threat called for a drastic increase in range, speed, and endurance of interceptors, NORAD expressed doubt that the proposed system was the answer. It appeared to go too far into the ballistic defense area, thereby over-complicating fire control
and armament requirements and, perhaps, over-lapping projects already in the mill under the "family ofweapons'' concept of air defense. Also, the 3-kill capacity was too low for NORAD's requirements.

Thus, NORAD's criticisms remained the same: the proposed system appeared to be too complex and too expensive. NORAD doubted that it could be developed in time to meet the threat.

Here the matter rested at mid-1961. The situation seemed to be that nothing further would be done until a study underway in DOD was completed on a super interceptor capable of meeting the requirements of all the services.

 

[patburke06]

Interesting is there any photos of mock-ups or concept art?

 

[iverson]

Cancelling the F-108 and the various IMI projects seems more fortuitous than ill-advised. They were designed in response to a non-existent bomber threat that was probably already known to be non-existent but was politically expedient for the USAF. Speculative requirements involving science-fiction levels of performance unconstrained by cost did nothing for America's defenses. Had the F-108 et al proceeded, we would have been even less well-prepared for the air wars that we had to fight in the coming decades than was actually the case.

 

[Archibald]

200 miles ?? 360 km - this is freakkin' ISS altitude ! Mach 5 in comparison falls far from orbit (= Mach 26).
Maybe they thought about militarizing a X-15 rocketplane; in turn these performances looks like ISINGLASS (ramjets to mach 5) and RHEINBERRY (suborbital, with a rocket).