Brian Abraham
Talking about the 71 Jane
Okay
FoxtrotAlpha18
A-12s were retired permanently in 1968 and the surviving YF-12 in the late 70s, and both only ever used the AFICS.
The dozen SR-71s equipped with DAFICS had much more stable inlets and weren't anywhere near as prone to unstarts.
The SR-71 first flew in 1964, and entered service in '66. DAFICS wasn't installed until 1980.
The inlet doors could be 'fine tuned' in flight by the pilot
As I understand it, the inlets were either functioning fully autonomously, or the aft-bypass doors were controlled by the pilot which affected the aft bypass doors indirectly. There was a manual override to control the spike and so forth in the event of a malfunction.
but on the occasions when it did happen the system would actually unstart the 'other' engine by pushing the spike back out in order to arrest the yaw.
Not exactly... the other engine would go through the same restart cycle to reduce the degree of yaw produced by the unstarted inlet. They called this a sympathetic unstart. This was applied at some point on the A-12 program then applied to the other designs.
This of course means that the unstarts encountered early in the program were far more violent than most encountered later.
I've been told by a former SR-71 driver that every jet was different and had its own little inlet idiosyncracies
That's correct.
hval
A delta-winged aircraft has a number of disadvantages: it cannot use flaps, and so has a long takeoff run
Actually a delta wing can use flaps -- you simply need leading and trailing edge flaps working together. One produces lift up front, the other in the back. It doesn't work as well as a tailed design though.
As for takeoff run, that depends on the takeoff speed of the plane and it's acceleration. The F-102's and F-106's had rotation speeds of around 125 kts, and a lift-off speed of 140 kts which is quite low. Acceleration rate is determined by thrust to weight ratio, drag of the airframe and it's attitude on the ground, and the inlet design (a short inlet which is often used on subsonic aircraft works very well; a long inlet designed with geometries for supersonic flight does not work quite as well because it's longer and its geometry isn't as optimized for supersonic flight).
its low wing loading makes for a rough ride at low altitude, even though the B-58 actually gave quite a good ride at low altitudes.
The B-58 didn't have a very light wing-loading. Typical takeoff weight was 163,000 pounds and very early on in it's service career it was increased to 176,000 (though rarely operated in this configuration); wing area was 1,542 square feet which yields a wing-loading of 105.7 to 114.1 lbs/ft^2. When the fuel capacity is reduced to 50% that brings the weight down to around 115,500 to 118,500 and the wing-loading to 75 to 77 lbs/ft^2 which is still pretty high (it's heavier than a fully loaded F-100 at takeoff weight). Though wing-loading isn't an absolute as far as I know for low altitude ride, aspect ratio among other factors are important too -- from what I remember reading (I think Phil Rowe's site) it did ride rough on the deck at least at certain loads (during a test flight, it was said to have flown rough on the deck).
A delta wing aircraft loses speed quickly on turns, limiting manoeuvrability.
Depends on what speed you fly it at...
The MiG-21, F-102A, and F-106A all had delta wings and had similar turning performance. At Mach 0.8 @ 15,000 feet (which IIRC is around 420 kts) they could sustain in excess of 6g's in a level turn. As you slow down the L/D ratio falls off quickly and airspeed bleed-off becomes excessive.
This was a test of inflight shutdown and restart of the engines at supersonic speed. It has also been said that there may have been carrying out tests on side loads for the fin. I am not sure how true this is.
It almost certainly was the former, though the latter could have been conducted simultaneously as the yaw, sideslip, and rudder application would all put a load on the rudder.
The test was simulating outboard engine failure at Mach 2. A failure of the Yaw Damper caused the aircraft to yaw at supersonic speed
I'm uncertain what kind of yaw-damper malfunction would have produced this result, as virtually all engine failures in multi-engined aircraft induce yaw (an exception being the EE Lightning) requiring opposite rudder input, so the pilots would have just had to apply a little more rudder than they were expecting. The only thing I could think of would be that somehow a dutch-roll started and the crew overreacted with rudder inputs, or; the yaw damper swung the rudder the wrong way; the yaw damper swung the rudder left and right in rapid succession, over-stressing the tail.
and the shock wave entered No. 4 engine while No. 3 was shut down
Hmmm, if they were simulating an outboard engine failure -- they would have cut engine 1 or 4, not 3. As for shock-waves entering the #4 engine -- that seems nonsensical -- I did some reading and the B-58 had an interesting problem called "fuel stacking" which occurred when the tanks were half empty and it seems that it could come very close to endangering the structural integrity of the aircraft and no engine problems seemed to occur. Could be wrong though
It was determined that a number of factors had contributed to the accident. The official report noted "design deficiency in that the directional restoring moments on the aircraft were not adequate for the test conditions".
So the plane wasn't directionally stable enough?
This was a deficiency in the tail fin structural integrity and a complex aerodynamic phenomenon that involved the aircraft’s large elevons and a small set of control surfaces at the wing root that served as trimming devices.
I don't remember the B-58 having any small trimming devices other than the elevons at the wing-root -- it almost looks like they're talking about something like the F4D's trimmer-vanes.
Regardless what they're talking about seems almost like a problem that occurred with the F-15 during it's test period -- there was an aeroelastic problem with the booms (the trailing-egde root-extentions) which mounted both the horizontal and vertical tails which ultimately was fixed by putting a dogtooth on the tail.
From an engineering point of view (maintenance) the B-58 looks like it may have been somewhat difficult to maintain from systems to airframe.
Yes, it was. The electronics were very complicated, which included the bomb-navigation system (which in turn included a star-tracking system, a doppler system, and a downward looking radar), the automatic inlet-control system, while I don't know how complex this was at the time, the aircraft was automatically trimmed; it had a sophisticated autopilot which could also automatically adjust the C/G position in addition to fly the plane; it had a radar in the base of the tailfin (not that complex for the time, but it all adds up) to feed guidance data to the turret (which truthfully was unnecessary for the aircraft), it had a very advanced jamming system.
Mechanically, it was complicated in terms of the honeycomb panels which include stainless steel honeycomb-panels in the leading and trailing-edge, and the elevons; aluminum/aluminum and aluminum/composite honeycomb-panels which were expensive to make, expensive to replace, and the composite cored panels corroded. The landing gear system was complicated due to the need for the wheels to have the clearance to make the ground with the pod on it and be able to retract without hitting the pod, so the nose gear had a joint on it; the main gears flipped up to lie flush with the strut, which then flipped back into a fairing. The actuators for the inlets also probably required a decent amount of maintenance.
Definitely special going those speeds, even if it could only do mach 2 for 30 minutes.
That doesn't sound right. A supersonic range of 2,000 miles was admitted to early on which means an endurance of 90 minutes minimum; in a book written about the B-58, I think it was stated that it's radius was 4,000 miles with a supersonic radius of 2,000 to 2,500 miles.
BTW: I don't want to be perceived as arguing with anybody -- that is not my intention.