ryan1234
Desensitized Member
Ha - I was actually being serious... and by "here" I meant where I work.. He's a fairly well known guy in the Naval Aviation world.
Forward slipping a swept wing, transport category jet
- Thread starter jtrain609
- Start date
Ha - I was actually being serious... and by "here" I meant where I work.. He's a fairly well known guy in the Naval Aviation world.
ryan1234
Desensitized Member
Whatever happened to the engine upgrade plans for the A-10?
Hacker15e
Who am I? Where are my pants?
I was sitting in a pilot briefing at my squadron where the Wing pilots were being briefed by the CC of the AFRES/ANG Test Center about new engines for the A-10 being bought, paid for, and ready to install........
.......problem is, this briefing was back in the year 2000.
MoMatt
Well-Known Member
So, pardon my dim-witedness, but can someone explain why, on a swept wing design (think global or DC10, or B52!; something with an aggressive sweep) if you enter an aggressive, prolonged forward slip (full rudder) that it doesn't create a roll / over-the-top stall towards the trailing wing? In other words, once in the slip, the "forward" wing has an effective sweep of say, 0 degrees, with almost all chord-wise flow while the trailing wing now has an even larger sweep, with a whole lot more span-wise, non-lift-producing flow.
I was taught this was the reason you don't forward slip a swept wing jet and I haven't seen it brought up here. Just wondering if this was bunk reasoning. Where's tgrayson when you need him?
I was taught this was the reason you don't forward slip a swept wing jet and I haven't seen it brought up here. Just wondering if this was bunk reasoning. Where's tgrayson when you need him?
seagull
Well-Known Member
Obviously you have dihedral effect with a swept wing. So, it wants to roll with the direction of rudder push, and you offset it with aileron. Not a big issue. One thing that can lead to higher sink rates is if you get to the point where the aileron input leads to spoiler activation. This increases sink rates.
None of this is an aerodynamic issue, as the same happens on crosswind landings. The difference, however, is that on a crosswind landing you are (hopefully) on GS and not trying to lose a bunch of altitude, so the vertical path is controlled by the addition of power. If you are doing a forward slip, presumably you are trying to lose altitude, so you would be at idle power. Now you have a very high vertical descent rate with idle power. Not a good combination in a jet.
So, can it be done? Aerodynamically, yes, but the question is whether it's smart. If you are that high the go around is the better option, absent an emergency.
ryan1234
Desensitized Member
Just seems like with the C upgrade, it only makes sense to upgrade the Engines as well... so many advantages long term.
seagull
Well-Known Member
Tgray is around, just not on here lately.
As for the reasoning, while what you said is true, my response would be "so what?". How would that be an issue at all?
dasleben
That's just, like, your opinion, man
Seagull's post is backed up 100% by the applicable manuals. You would need opposite aileron in order to counteract the roll tendency from the upwind wing, but it's not a big deal as long as you're ready for it. Speaking for the 757 and 767, that rolling moment is benign and easily controlled without roll spoilers.
MoMatt
Well-Known Member
Yeah, it makes sense now. Thanks! It was one of those things that an instructor taught me long ago and it stuck before I really thought critically about it and years later it seemed like gospel; IF YOU SLIP WITH A SWEPT WING IT WILL STALL AND SPIN!! When in reality the effect is much less exaggerated and the application of aileron balances it out.
Somewhat, but not really. We've built our tactics around what we have. The new engines proposed were somewhat heavier, yet with negligible thrust benefit. Making the aircraft heavier won't necessarily help. What the fleet has, works, albeit with long-known limitations that have for the most part been accounted for.
dasleben
That's just, like, your opinion, man
I'm not a check airman or in any position to judge the way people fly (with my extensive experience of 250 hours of heavy time!), but one thing I've noticed is that some people treat big jets as if they're unlike anything they've ever flown before. Sure, it's big, but it's still an airplane. Houses get bigger, houses get smaller, all that. There are certainly things that can bite you in something big that wouldn't be as much of a factor in a smaller airplane, but I think a lot of the "Oh my god, don't do that in a jet!!!111" is overblown. This airplane flies like a big cuddly teddy bear.
ryan1234
Desensitized Member
ryan1234
Desensitized Member
Already told you my F-35 story, I think, from long ago.
Of course those are advantages, yes. But wish list aside, we've had to cope with the reality of funding, or lack thereof. It's why i don't believe anything regards upgrades or new aircraft until they're sitting on the ramp, and hence why we've just continued to do the best with what we have. Engine upgrades have been in the wishlist of the A-10 for a few decades now, but systems upgrades and airframe modifications always trumped the engines. These days, one can't have the whole enchilada like days long ago. Kind of like that Christmas present thats just too far out of the realm of reality.
So that being the case, it came down to this:
Lessen the fuel/ordnance load if takeoff factor is truly an issue, otherwise the normal bases we fly out of, it isn't. Unlike the '80s, we won't be operating out of dirt strips anymore likely.
Not that the jet really operates that high to begin with.....medium altitude at best with the modern weapons (low altitude primarily before that); this would really be a factor for air refueling or XC's. On AR, a tanker tobbagan is accepted and expected; XC can suck up the extra time.
A nice to have, but not really a need to have. We've been operating without this and still with excellent maneuverability and have been fine. Would I like to have it? Sure. But it's never been put high on the list.
Another not need to have, nice to have yes. Jet flies fine with how we load it out, and rarely is it at full combat weight anyway.
Nice to have in a pilot fatigue sense, but not need to have. We'd still need the same tanker per 4-ship, though we could likely substitute a KC-135 for a KC-10 possibly. Still, while it sounds good, this is more hype than major reality.
Nice to have. Been here before. Again rarely at max gross, and even at fields where temp/PA show us with a slow climb rate, thats what the external jettison button and fuel flow override switches are for.
So that being the case, it came down to this:
Lessen the fuel/ordnance load if takeoff factor is truly an issue, otherwise the normal bases we fly out of, it isn't. Unlike the '80s, we won't be operating out of dirt strips anymore likely.
Not that the jet really operates that high to begin with.....medium altitude at best with the modern weapons (low altitude primarily before that); this would really be a factor for air refueling or XC's. On AR, a tanker tobbagan is accepted and expected; XC can suck up the extra time.
A nice to have, but not really a need to have. We've been operating without this and still with excellent maneuverability and have been fine. Would I like to have it? Sure. But it's never been put high on the list.
Another not need to have, nice to have yes. Jet flies fine with how we load it out, and rarely is it at full combat weight anyway.
Nice to have in a pilot fatigue sense, but not need to have. We'd still need the same tanker per 4-ship, though we could likely substitute a KC-135 for a KC-10 possibly. Still, while it sounds good, this is more hype than major reality.
Nice to have. Been here before. Again rarely at max gross, and even at fields where temp/PA show us with a slow climb rate, thats what the external jettison button and fuel flow override switches are for.
jtrain609
Antisocial Monster
I want to say something snarky about the A-10, and Mike, and about how Mike's a hack, but I don't want him to forward slip a Mk. 84 into my house
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