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-   -   USAF Hypersonic Missile Test: successful (https://www.pprune.org/military-aviation/646735-usaf-hypersonic-missile-test-successful.html)

Lonewolf_50 17th May 2022 12:45

USAF Hypersonic Missile Test: successful
 
https://www.airforce-technology.com/...rsonic-weapon/

After a few false starts, the USAF's hypersonic missile test has had a success, from the venerable Buff. As I meandered about the net, a few articles came up with the point that DARPA needs to have a successful hypersonic missile (which they call ARRW) so that they can figure out a way to counter them, since it is known that peer competitors have them already.
ARRW means air-launched rapid response weapon.

Originally Posted by tidbits and major points from the article
  1. After separating from the aircraft, boosters of the ARRW ignited and burned for the expected duration required for achieving a hypersonic speed, which is five times greater than the speed of sound.
  2. The milestone achievement comes after a series of tests conducted over the past few years, with the first test conducted in June 2019.
  3. According to the USAF, ARRW will allow the US forces to defeat time-sensitive, fixed and high-value targets from far distances in a contested condition.
  4. The long-range hypersonic AGM-183A ARRW will also improve the precision-strike capabilities of the USAF, by launching rapid response strikes against protected land targets.


Sue Vêtements 17th May 2022 16:01

I wonder how you steer something going that fast. Not just the reaction time, but the forces involved too

Maybe you don't

MPN11 17th May 2022 16:13

VERY small wings/fins? Made from Unobtanium, of course.

henra 17th May 2022 16:20


Originally Posted by Sue Vêtements (Post 11231572)
I wonder how you steer something going that fast. Not just the reaction time, but the forces involved too
Maybe you don't

That generally appears to be the Achilles heel of those wonders missiles. China celebrated a successfull test which had a CEP of ~20 Miles (!!!).
Regarding the capabilities of the Kinshal not much seems to be really clear. Neither speed nor accuracy are really known. There might have been some more knowledge gathered if they have really been used in Ukraine (which Russia claims but where there were some doubts).

ORAC 17th May 2022 17:35

Well the Shuttle managed a series of 4 S-turns at 40 degree AOA and 70 degree bank angle on every re-entry between M25 to M10 every trip - so they seem to know how to handle the problem…

MPN11 17th May 2022 18:57


Originally Posted by ORAC (Post 11231610)
Well the Shuttle managed a series of 4 S-turns at 40 degree AOA and 70 degree bank angle on every re-entry between M25 to M10 every trip - so they seem to know how to handle the problem…

Not being confrontational, because I’m sure you know more that me, but … what was the air density during those high-speed manoeuvres?

Sue Vêtements 17th May 2022 19:06

I read somewhere that a standard rate turn through 180 degrees at Mach 3 in the SR71 took the craft all the way from the border with Canada to the border with Mexico :eek:

uxb99 17th May 2022 19:18


Originally Posted by Sue Vêtements (Post 11231656)
I read somewhere that a standard rate turn through 180 degrees at Mach 3 in the SR71 took the craft all the way from the border with Canada to the border with Mexico :eek:

A missile doesn't pass out though.

SATCOS WHIPPING BOY 17th May 2022 23:52


Originally Posted by Sue Vêtements (Post 11231572)
I wonder how you steer something going that fast. Not just the reaction time, but the forces involved too

Maybe you don't

Article implies the main target will be static land-based or slow moving ship targets. Manouverability shouldn't be a major requirement for a missile travelling at 6000 or so m/s.

Ascend Charlie 18th May 2022 00:40


I read somewhere that a standard rate turn through 180 degrees at Mach 3 in the SR71 took the craft all the way from the border with Canada to the border with Mexico https://www.pprune.org/images/smilies/eek.gif
Standard rate = 180 degrees in 1 minute. Somehow I doubt that he could get from Canada to Mexico in 1 minute, even in a straight line.

golfyankeesierra 18th May 2022 05:53


Originally Posted by Ascend Charlie (Post 11231746)
Standard rate = 180 degrees in 1 minute. Somehow I doubt that he could get from Canada to Mexico in 1 minute, even in a straight line.

Yes, at 180 kts.
Do a 360 at F350 at 480kts and it will cost you about 8 minutes, you can calculate the radius from that one.



beardy 18th May 2022 07:04


Originally Posted by golfyankeesierra (Post 11231804)
Yes, at 180 kts.
Do a 360 at F350 at 480kts and it will cost you about 8 minutes, you can calculate the radius from that one.

A standard rate turn otherwise known as a rate one turn is 3°/second. The speed and altitude are irrelevant.

Smalahove 18th May 2022 07:27


Originally Posted by Ascend Charlie (Post 11231746)
Standard rate = 180 degrees in 1 minute. Somehow I doubt that he could get from Canada to Mexico in 1 minute, even in a straight line.

Great circle route CBB9-MXL: 1002 nm

Just This Once... 18th May 2022 07:28


Originally Posted by golfyankeesierra (Post 11231804)
Yes, at 180 kts.
Do a 360 at F350 at 480kts and it will cost you about 8 minutes, you can calculate the radius from that one.

A correction, as a rate 1 turn really is 3deg/sec, so a 180deg turn does take 1 minute. The example you give is not a rate 1 turn and the parameters to maintain one are directly proportional to TAS (not altitude per se).

I think you are confusing the bank angle recommendation (25deg etc) that is used for IMC flight. As TAS increases the AoB required for a rate 1 turn also increases. If you cap the 'rate 1' turn at no more than 25deg AoB (due to the physics of gin/tonic/ice/lemon or lime interactivity) when more AoB is required to maintain it, it is no longer a rate 1 turn.

[email protected] 18th May 2022 09:09

At normal human speeds, the required AoB for a rate 1 turn is simply approximated by knocking the last digit off the TAS and adding either 6 or 7 depending on which you prefer - 90 Kts gives 9 + 7 or 16 deg Aob (so fly to 15) 120 kts gives 12 + 7 = 19 Kts (so fly at 20).

Not sure how well that works when you are doing Mach 3 at 35000' and your TAS is in the region of 1800 Kts :)

Circa 30 nm/min makes for a big turn but not Canada to Mexico....

Lonewolf_50 18th May 2022 13:55

There was an article circling around some years ago that captured a talk given by an old Blackbird pilot who described how long it took him to turn around after a photo run over Lybia. I'll see if I can find the link, but I also think that somewhere on this very forum that story is available. First search didn't find it, though.

megan 18th May 2022 15:31

From the SR-71 manual. Turns were typically made at 35° bank, at ISA temp and 3.2M radius would be 70NM and take about 8 minutes for 180° turn, about 220 track miles.

Just This Once... 18th May 2022 15:42


Originally Posted by Lonewolf_50 (Post 11231987)
There was an article circling around some years ago that captured a talk given by an old Blackbird pilot who described how long it took him to turn around after a photo run over Lybia. I'll see if I can find the link, but I also think that somewhere on this very forum that story is available. First search didn't find it, though.

That would be a nice find as these anecdotal / real-world accounts from Blackbird pilots are usually illuminating as reading the books does not give justice to the complications of flying this beast at the edge of the performance envelope whilst actively controlling and/or monitoring the limits of engine technology, metallurgy, fuel tech, atmospherics et al, all whilst doing an operational job.

From the limited teaching we had on the SR-71 on the hard sums coarse I know that a suitably light SR71 that was somehow / actually in the best bit of the CofG envelope, with sufficient LN2 density, operating at a lower altitude that also happened to be unusually cold, with intakes in fully automatic (and trusting that they would remain so(!)) at a reduced mach number (say M3.0 or below), in a flight regime that allowed up to 25º AoB whilst remaining within the limited AoA range etc, then you could probably achieve a turning radius of under 100nm. Easy.

I recall that real-world ops tended to have few, if any, of the favourable conditions above and with an AoB limits reducing towards zero makes turning at operational altitudes / mach a serious challenge. I do recall (with reasonable certainty) that any manual control of the intakes (as an example) at typical operational altitudes had a 0º AoB limit. Tricky.

I doubt any of us without direct experience of this incredible aircraft will ever appreciate the performance complexities that came with operational flying. What was routine for them would normally require an experienced TP, telemetry, support TPt and a massive technical support team behind them working the live data at carefully controlled test points. It was in a whole different league.

I think LOMCEVAK had a very good insight into the aircraft at one point and I am sure he would have loved to have added it to his logbook. I don't think we have any ex-Blackbird pilots on this forum and those that may have flown a similar type probably don't exist anywhere!

Lonewolf_50 18th May 2022 17:33

Just This Once; Here's a related story about outrunning a SAM over Libya in 1986.

tdracer 18th May 2022 18:58


Originally Posted by megan (Post 11232029)
From the SR-71 manual. Turns were typically made at 35° bank, at ISA temp and 3.2M radius would be 70NM and take about 8 minutes for 180° turn, about 220 track miles.

Back in my college days, we had a lot of USAF pilots in our classes (who the Air Force had sent back to get advanced degrees).
One once made a comment regarding the viability of the YF-12/SR-71 as an interceptor to the effect 'You'd better get the bomber on the first pass, because it takes two states to turn around'. Sort of depends on which states you're referring to, but 220 miles sounds consistent...


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