- Dec 4, 2006
But to regain control of one in an inverted tumble is a significant achievement on the part of the aircrew. Much can be done at the edge of the ACs design limits...in fact there once was a C-130 aerobatic team called the Four Horsemen.It certainly looks like a shoebox with wings but it's surprising more agile than it appears:
You're hitting the nail on the head, with standardized parts. With the current set up, one spare engine can essentially replace four. If you switch to counter rotating props, like on the A-400, you now need two spares for four engines. This gives you a bigger foot print, and less reliability.As much of a debacle as the F35 is (and failure to apply lessons learned regarding mixed service requirement aircraft/airframes like the F-111), you're missing the point. It's not cost, it's the fact that you'd have to have a reversed drive section for the turboprop, and that whole deal is unitized. That means logistically you would need to have spares on-hand wherever you were storing and doing maintenance (depending what spare parts are actually held by the different associated squadrons doing dedicated 130 maintenance) of different engines.
Right now, if you lose an engine for whatever reason, you just replace the engine. You have X amount of spares that will work in any mounting location on the airframe. You also have a unitized powerplant that has it's quirks, but untold amounts of hours of known function and tolerances.. and wiggle room if you need to squeeze more out of it.
The new counter-rotating turboprop unit would have to be tested, and it also would have the same teething problems that the original engine had at it's early inception. You would have to also rework every single airframe because the mounts, while quite possibly being symmetrical in design, still have only been tested for specific torque factors in one direction (I'm not a pilot, but Beta on a turboprop isn't 100% on most of them, the herc may very well be different) in both thrust and thrust reversal conditions. Not only would the airframes have to be tested, but you'd have to idiot proof BOTH engines then in terms of say, the mount having one BIG bolt and one TINY bolt on opposite sides of the engine package in order to physically make it impossible without gross mis-installment, to put a right engine on a left engine mount, or vice versa.
They did it for a reason, knew the limitations, and the bird has done great. Maybe JedisonsDad might be able to expand upon why they went with a counter-clockwise target rotation and left side mounting for weaponry on the AC-130, given that this specific airframe behavior exists.
Well if you're in the AO currently, walk on over to our building and I'll get you a ride. Just PM first so I can make sure I'm there. Or, if you're ever in my neck of the woods home station, I might be able to work something.I figured that was the specific reasoning for doing it, even with that flight pattern/aircraft orientation having possible negative aspects. I remembered from my one whopping flight on an AC-130 how things were in terms of on-bird process and overall clif-notes level configuration of equipment.
I don't know next time I'll make my way out there, but I'll hit you up.Hah. Invitation appreciated, however I am long out of uniform at this point. If you ever come through North NV though, beer and accouterments could be arranged easily.
I did happen to get to keep something as a memento of that ride, although it was surprisingly hard, in a Navy town no less, to find Brasso to polish it up when I finally thought about doing it. I can say that if I had the opportunity to go AF, being AC-130 aircrew would be high on the list of jobs I'd bust my ass to get into. I'd need a PTT vs intercom if I was on a joystick, since my running commentary would be best left off the in-flight recorder... "How'd hiding under that tree work out" "Fuck you, your truck, and all your brohams" "Ragdoll Physics for the win!" etc...
1) State for the record your J model experience. Anyone interested in my bona fides can PM and I will explain exactly what my involvement is regarding this subject.Knowing a bit more about the situation, and having talked with both mishap crews, it's deceptive to claim pilot error.
Part of the fault is on the design of high powered propeller aircraft. The rotation of the props cause a gyroscope effect that naturally wants to pitch the plane nose down, and roll it left wing down. I have been taught this and experienced it many times in the simulator. Add in the smarts of the J model, that senses it is stalling and adds power to save itself, and suddenly in a left hand turn, the right wing suddenly has massive amounts of lift, due to the blown wing design of the -130. This causes the right wing to lift even more, taking the bank to extreme, and in this case, nearly unrecoverable angles.
The J model, so far, is less than ideal as a gunship platform.
I just looked you up in the Global and for the members reading this.: You can PM Vat_69, but he's "kinda smart" on the AC-130J.1) State for the record your J model experience. Anyone interested in my bona fides can PM and I will explain exactly what my involvement is regarding this subject.
I didn't talk to "somebody, who knew somebody, that flew a gunship once"1) State for the record your J model experience. Anyone interested in my bona fides can PM and I will explain exactly what my involvement is regarding this subject.
2) "Add in the smarts of the J model, that senses it is stalling and adds power to save itself, and suddenly in a left hand turn, the right wing suddenly has massive amounts of lift, due to the blown wing design of the -130. This causes the right wing to lift even more, taking the bank to extreme, and in this case, nearly unrecoverable angles."
Entirely false. ATCS does this only during takeoff.
(To reduce the air and ground minimum control speeds, the C-130J is equipped with an Automatic Thrust Control System (ATCS).
The ATCS reduces the asymmetric thrust moment caused by an outboard engine failure by automatically reducing the thrust on the opposite outboard engine.) Only below Vmpr, essentially only during takeoff.
2.1) "The J model, so far, is less than ideal as a gunship platform." The F you talking about? I guess zero noise signature and 10 hour legs are less than ideal? I bet the snake eaters beg to differ.
3) BL: Nothing wrong with the J Model. It flies EXACTLY as designed and as any plane will when intentionally placed in a high angle of attack stall, extreme yaw; sprinkle in a roll rate and KAPOW full blown spin. Your grandpa's Cessna (or any plane for that matter) will behave the exact same way. You be the judge of why the Test pilots were allowed to do it twice. All I can say is it didn't come from the bottom up. IMO SOF entities did this to themselves.
4) It's a goddamn shame this was allowed to happen. Thankfully no one was killed.
Don't try to pass rumor as intelligent commentary because, "you talked to somebody, who knew somebody, that flew a gunship once."
We like to think it is a bit more than,"it's just the internet" here on ShadowSpear. That said, I suggest you take this to pm, if you want to continue this discussion, in this manner.I didn't talk to "somebody, who knew somebody, that flew a gunship once"
If you check who I am, you might see that I'm not some random person. Based off of Freefalling's comment and your location, I imagine you're somebody that I might know, perhaps even flown with. But whatever, its just the internet.
I did take it to PM.We like to think it is a bit more than,"it's just the internet" here on ShadowSpear. That said, I suggest you take this to pm, if you want to continue this discussion, in this manner.
I didn't need to assume your background. You are clearly aircrew on legacy gunship. That was obvious. What I meant to say was you talked to somebody, who knew somebody, that flew a J gunship once. I missed the J part. I am aware that you are very knowledgable, just not about J gunship specifics.I did take it to PM.
Also, on Shadow Spear, isn't it also preached to not spout off at someone without knowing their background? Isn't that exactly what he did when he accused me of knowing a guy who knew a guy that once flew? I'm not outside my lane. Going off of Free Falkings comment, Vat 69 is somehow related to Gunships, possibly a crew member. I too am a gunship crew member. I've got a broad experience on them, having flown and deployed in both the AC-130H Spectre and the AC-130U Spooky. I'm also not some irrelevant crew position (system knowledge wise) on the plane. I am a Flight Engineer. My entire purpose on the plane is to be a systems knowledge expert. My job involves understanding every aspect of the plane, how it flies, and ensuring that it continues to fly. When the pilot can't figure something out, he turns to me for the answer. Granted, I haven't flown the AC-130J, but I am familiar with its systems, and the basic principles of aircraft flight, blown wing design, and gunship orbit and firing geometry. I can't immediately see who Vat is right now, as I'm currently deployed, but I at least did the professional thing and didn't say he didn't know shit without knowing who he was.
I've already sent him a private message, as I'm sure I probably know him.
Everybody that I've talked to that was flying the plane that day, and also the other time, said that the addition of power caused the plane to roll as I described. It never entered any sort of flat spin, or anything like that. But let me caveat by saying I have no J model experience, I just talked to the co-pilot that recovered the aircraft the second time.This post is in no way intended to call out anyone...just looking for additional insight/increase my knowledge.
@Vat_69 , can you help clarify a couple things:
In your post (item #2), you mention V-mpr. I'm not familiar with that v-speed? Did you mean V-mp (min. power) or is this something different?
Also, you mentioned the J-model in a spin in this accident (#3). It's not clear to me... I read this event to be, essentially what I'm familar with, as a "rudder stall". Did the aircraft actually enter a spin that was just not called out as such in the report or was it something else?
In reading through the accident report, while it mentions an objective of exploring stall characteristics, I didn't see any overt mention of a spin, aside from refrences to the Feb 2014 departure of the C-130J. For this accident, I only saw the event described as a left roll inverted into a dive. I've read a fair number of accident reports and, with spin having very specific aerodynamic meaning, I guess I would expect that to be called out. You mentioned "grandpa's Cessna" and having flown many a Cessna, including Aerobats, they're very stable and require some effort to get them to enter a spin. However, the numerous times I've spun the airplane, I've never come close to having it roll inverted.
In this case, they first completed the sideslip to the right without even encountering a rudder alert but easily encountered it when slipping to the left.
As such, with a steady heading slip, JedisonsDad's description of keeping power in, rolling left and ultimately coming over the top makes sense; sounds very similiar to an engine-out, rudder stall scenario on a small multi-engine (ie. Baron, Apache, etc)? The LM re-enactment sim probably provides this detail but I haven't seen and probably won't see that.
Hopefully all that made sense. Understand if this is not something you can/want to share.
They said they were testing stall characteristics in an orbit.Vmpr is min power restoration speed. So, yes the plane in fact experienced rudder force lightening, rudder fin stall as we used to call it. The way the plane enter that is how you intentionally try to spin a plane, at least it was when I went through pilot training. It nearly impossible to spin stable aircraft which the C-130 is, so technically the plane did not reach a full spin, had the plane not been recovered, I believe it would have entered s full spin. I have spun a Cessna and it was hard to achieve. Hard in a T-6 as well, both scenarios the plane rolled inverted. The addition of power, like Jed said, certainly didn't help because of the factors he mentioned. However, stall recovery procedures (max, relax, roll, neutralize) are correct. The roll off to the left should be expected, however without neutralizing the rudder the plane will continue to roll, in this case inverted. The roll to left is recovered by maintaining it until the nose attitude drops and airspeed increases. As aileron control improves, you begin to roll wings level and pull towards level.
Full rudder deflection is a bad idea period in any plane with a high angle of attack and high power on your prop or props. The question to ask is why they put it there in the first place.