Looping a B-1 Bomber!

The C-17 guys can do it with that super high speed descent trick where they put a couple into reverse and drop out of the sky at 15-20k on the VVI. It's not allowed I wouldn't plan on trying it in the C-130E/H and you couldn't even do it in the J model without figuring out how to trick the engine management. The guy(s) that did it straight up screwed up.... But sometimes it takes an idiot screwing something up to do the things sane people only talk about.

They didn't crash it. If I recall correctly the props all decoupled momentarily and there may have been some negative Gs which triggers all sorts of inspections. But the airplane wasn't permanently damaged. Not saying it was a good idea (much like looping a B-1) but it can be done. That seemed to be the direction this thread was going.

 

Why would you go to full power when you are pointing the nose down? You said roll inverted, mil power, pull? Why not roll, flight idle, and pull?

Also, and this might be a B-1 specific thing that no one on here knows, but does it have speed brakes that you could pop as you are pointed straight down? That might help with the speed a bit.

 

There was, a number of years ago a regional airlines pilot that routinely did reverse props (turboprop) when he landed... shortly before the threshold... came in fast and high. Bragged to FO that it worked great.

One time it didn't and he hit hard. Plane was a loss. Don't remember if there were fatalities but there were injuries I recall.

I'll try to find a link.

 

I figured you might ask, but it has to do with maximum performance on the edge of the V-G diagram. Remember, I postulated a maximum performance pull starting at 10 knots above stall. Starting a pull here is presumably way below corner velocity, and while the turn rate with the nose transitioning downward towards vertical will be high, it will actually increase until corner is reached. That said, I want to be able to pull the nose through as many degrees as possible just above stall in the least altitude as early as possible before I get into Taz's "impossible" (90 degrees nose low) zone of the maneuver. Since I entered just above stall, power at mil will actually help me pull harder sooner in the maneuver. As soon as corner is reached, pull at corner or Max G in that order until you either hit the ground or recover to enjoy tea and crumpets back at the mess.

Edit: To be honest, the right BFM text book answer would be Full AB for this maneuver! But I could only determine the best way to do this by looking at the V-G (also knkwn as V-n) diagram, amongst other B-1 specific limits of which I have no clue. Hence...Don't try this at home!

 

On F-111s doing 30 degree dive bomb runs (something we never did in combat, since it was all at night), you used 35 degree wing sweep for more lift and drag and went to idle power on roll-in. Altitude loss was still very high and, without idle power, we would have been supersonic on pull-out. F-111s and B-1s are very clean, and nose down velocity increases at a prodigious rate. The F-16C and F-15C could not stay with an F-111F in a drag race through the mach, even in level flight, and nose down was not even a contest. Only the Mig-23 and late F-14s (Cs and Ds) were clean enough and had high enough T/W ratios to stay with an F model through the mach. The B-1B is similarly clean, but does not have nearly as high a T/W ratio. That high wing loading, however, lets it accelerate very rapidly using God's g (nose low).

So I think you would probably kill yourself trying to do a split S in a B-1B, especially since the high wing loading means you are starting from a relatively low altitude (the 20s) to begin with.

 

I get that you think it can't be done. I'm not saying that you're wrong. Still, everything above about 30 degree DB runs at idle doesn't relate to a split S other than as an emotional evocative that the airspeed increases [too] fast with the nose pointed at the ground. All aircraft do this. In a DB run you want to maximize time on final to get a firing solution and remain above Safe Escape or the designated floor or the ground, depending on what you're dropping or spitting. In a maximum performance turn in the vertical, by contrast, the fastest recovery is attained by reaching corner velocity as rapidly as possible, the point where the maximum G load can be pulled without stalling the aircraft which in turn provides the maximum nose track in degrees per second. In the case of a split S starting just above 1G stall inverted, I'd actually be counting on the developing nose low attitude and increasing airspeed to help get the nose to vertical in the least altitude possible. Idle power and speed brakes in the vertical would make it worse anywhere before corner velocity. It's very counter intuitive. Detailed analysis of velocity-load diagrams isn't an everyday task for most pilots and hence may make this discussion confusing. That said, it's still fun to think about!

 

Will- Being a weapon school graduate and with a chemistry degree, those diagrams are not too complicated. Unfortunately, your background in a high L/D, low wing loading aircraft is in a completely different portion of the flight envelope than those of us that were in high wing loading, low L/D aircraft. The two worlds are hard to directly compare or draw inferences from personal experience.

 

Wow. Okay. I guess I should just shove off and discuss it with the rest of my undereductated 3000+ hour fighter pilot buddies who are also board certified surgeons. Maybe if enough of us got together, our collective science, math, and technology backgrounds would lead us to just throw our hands in the air and declare that the B-1 is simply too big, too sleek, and has too high a wing load to ever make it through a vertical 180 degree turn.

By the way, Taz, I never meant that V-G diagrams might be confusing to you. I said this as another poster had asked about the impact of using full power to effect a nose low recovery with the least altitude loss.

 

Will- Not my point at all. I have time in the F-16, F-15 and F-4 and they are completely different, and enjoyable, experiences from flying an Aardvark or B-1B. No time in the Bone, but I have a B-1B weapons school graduate friend I will have to ask. My personal opinion is the physics will just not work. You start from too low an altitude, lose too much altitude in the turn, and have limited pull-out capability at the bottom. Turn radius in an accelerating, nose low, vertical turn is huge, especially with the relatively low L/D you want to keep drag low during terrain following.

 

Jacob- No sweat.