upside down

QUOTE: Originally posted by mscottholt Matt, Are the 'Hawks still limited to the 60/30 degree restriction or did it get rescinded for OEF/OIF?

As far as I know, meaning when I was there, we were still limited to the 30/60 rule. Then again you wouldnt want to manuver even to that extreme when you had wounded on board. I never even thought to ask my buddies over in the Lift unit next door. I think that the "powers that be" in the blackhawk community never even thought to modify those limitations.

In the AH-1G it was important to maintain positive G's on the rotor system when performing the split-s manouever or the aforementioned "mast bumping" would be induced in which case you and the bird were parts.
We would start by getting a whole bunch of air under our chair; 3500' AGL minimum. We reduced collective while pulling the nose up to bleed off airspeed. Unlike the Apache we wanted to be slow when the recovery dive was initiated in order not to bust our VNE (180kts). As the IAS passed below 50kts
we would roll the bird on its back. Since we were slightly nose up when the roll was started, the nose was already below the horizon when the bird got to the inverted position. As the nose came down we would maintain a constant increase in power (raise the collective) and maintain backpressure on the cyclic to pull the nose through. Airspeed built up fast and we would come screaming out of the sky. The steady increase in pitch kept positive g's on the rotor. Needless to say this practice was frowned upon and very dangerous. But we were kids with fabulous toys and very large boy parts.

Matt,
Are the 'Hawks still limited to the 60/30 degree restriction or did it get rescinded for OEF/OIF?

I have seen a sikorsky demo video of the hawk doing Hammerheads and 80+ degrees nose down spirals, among other manuvers. There are a few Helos that can loop but I know that very few sane pilots would even try it. I konw that I am restricted from anything close to that, still can give you a wild ride though!!

I saw the RAF Blue Eagles (helicopter demo team) on TV (can't remember if it was History Channel or Discovery) once and they did some really amazing things with their helos.

Here's their site:

http://www.deltaweb.co.uk/eagles/

Glider,

Sounds cool. Who do you fly with?

"I have never seen a helicopter do a "loop", but I suspect the AH-64 could do it, but I also suspect that it is a "prohibited" manouver(sp)."

Yep, it's a prohibited manueverfor us line pilots. Until recently we were limited to +-30 degrees in pitch, +-60 degrees in roll by the -10. Last year we were authorized +-60 degrees pitch, and +- 120 degrees in roll. This was due to combat experience gained in OIF. This was to accomodate new manuevers like the pitch back turn, which is similar and has the same purpose as a return to target, but has the advantage of maintaining a bit more airspeed throughout the manuever (done correctly, anyways).

The way to roll past 90 degrees without packing it into the ground is to be in climb when you do it. Start with at least 90 KTAS, preferably more, pull up, roll towards the target before you bleed off too much airspeed, aft cyclic to bring the nose in line with the target, roll out and let her rip.

Even so, most of us rarely go all the way to the limits. There's simply no purpose in doing so.

QUOTE: Originally posted by ridleusmc I saw a Sikorsky testing film from the early 60's in which they took a stripped down CH-53A to do a set of barrel rolls and a loop. Sure enough they did it, but According to the film, the airframe had to be retired.

I saw the same film (what hydraulic blooded 53 guy hasn't?!) Man that was an awesome stunt.

QUOTE: Originally posted by grandadjohn There is a difference between RC helo's and real one's, wouldn't want to be in a real one trying to do what the RC's do(and I sold alot of repair parts for RC helo's)

ohhh ya!

There is a difference between RC helo's and real one's, wouldn't want to be in a real one trying to do what the RC's do(and I sold alot of repair parts for RC helo's)

Upside down in the 9D5 is close enough.
Flying upside down? Not while my butt is inside.
Hovering, (?) at 40 Feet in 70knots of wind and 30 foot seas below is scary enough thank you.

Don

wow!
in my FlyRC magazine, there was this guy inverting his heli (model) and when the crownd screamed louder, he'd go lower, so later.
it said that he was literally cutting grass blades!
I bet that scratched his rotor

Back in the mid 70's I worked for a company that had a few of the first Bo-105's. With it's rigid rotor system it was capable of doing loops and rolls and only saw it on a demo tape. One day one of our pilots thought he had enough balls to do it but chickened out in the vertical and just did a hammer head. I was in the left seat! He did do some 90 degree banks at low atltitude that raised the hair on the back of my neck too. Something about aerobatics and rotors that don't seem to "mesh"! I also saw the Army Demo Team the Silver Eagles flying OH-6's in the mid 70's and they did some tricky stuff. During a performance during a windy day a hammer head turned into a loop and I doubt if he was at 500 ft. I have a picture of two going vertical, main rotors facing each other and they happened to be sync'd. If you draw a line down the middle it looks like a mirror image.

Man, I started downloading the Helo Thunder Video. I chose the Large edition, but it's taking forever. I need to upgrade from DSL to Cable.

QUOTE: Originally posted by AH1Wsnake (ok, correction.........) I beleive know he (jinithith2) is referring to a popular video game (re: "BF vietnam heli"). Any flight characteristics produced by those software designers have no basis in reality. The game is for fun, not a flight sim.

yes Battle Field Vietnam

I've got a copy of the "Helo Thunder" video that's been mentioned here (watch it before ever PT test!) and the maneuvers that the Apache pulls at the end are quite impressive to say the least. It basically goes from a barrel roll to a hammerhead and then corkscrews down. If anyone wants to see it, go to www.grouchymedia.com and you can download it there. Just do a search for "Helo Thunder". Its set to ACDC's "Thunderstruck" which is enough to get anyone going!

There is a good propaganda vid of the apache doing a split -S, Barrell and Loop/Clover combo. If I remember right the apache also was at an OGE Hover and did a barrell roll to show its maneuverability. on this video. Impressed the hell out of me. All fully articulated and fully rigid rotor systems can take Negative G's, I believe the Blackhawk and Apache approach -2.5G's, but that was a quote from an IP, not in the -10. Do a neg-G in a semi-rigid and you get into mast bumping and possibly a spot on the "Stupid Helicopter Tricks" video.

QUOTE: Originally posted by GeejeeZ I think the bottom line is that normal helicopter rotors cannot take too much 'negative G': one exception being the (navy-) Lynx, which uses some kind of 'reverse thrust' to push the helicopter to the deck of a moving shipdeck.

The Bell systems (two bladed) can not do negative, or evern Low-G as they get into what is called "Mast Bumping". A nasty situation leading to the airframe and rotor going their separate ways...

The lynx's blade angle is adjusted so that when the collective is all the way down, the blades have a slight negative angle, this is also sometimes present in the Bell's I fly. When we adjust "auto-revs" or the rotor RPM in autorotation, the engineers may have to put some negative angle on the blades to allow the RPM to stay where it should.

This causes a somewhat pronounced "hopping in the seat" when starting up or shutting down.
No helicopter can fly upside down. Only the Lynx and the BO-105 can do (Almost) unlimited aerodynamics, the apache can do some, and the cobra's can do less, BUT, if done carefully by trained aircrew, some can be done (Like Split-S).

I've seen the South African Rooivalk doing loops and doing quite a few of them.
They weren't F-16 loops but the Rooivalk was sort of upside down and they did it a couple of times.

Apparently this "loop" ability is quite unique. Will check some local sites and try and get more info.

My friend actually made a video clip, will check to see if he still has it.

OR Jinithith2 could be referring to the well known Cobra propaganda video from the Vietnam era, in which you see a Cobra do a half roll (during which it actually flies upside down for a second or so), to come out of it in a steep nose dive in the opposite direction.
I have seen a video of a Bölkow 105 doing a full loop. The Bo105 was a (the first?) helicopter with a rigid rotor system that (amongst other things) made it possible to fly inverted for a very short time.
I think the bottom line is that normal helicopter rotors cannot take too much 'negative G': one exception being the (navy-) Lynx, which uses some kind of 'reverse thrust' to push the helicopter to the deck of a moving shipdeck.
I must admit I have never been good at mathematics and related stuff, so please correct me if I have it all wrong.
Gertjan

(ok, correction.........)
I beleive know he (jinithith2) is referring to a popular video game (re: "BF vietnam heli"). Any flight characteristics produced by those software designers have no basis in reality. The game is for fun, not a flight sim.

QUOTE: Originally posted by jinithith2 oh, then is the for-a-fewseconds-upside-down-flight thing on the BF vietnam cobra heli incorrect? I'm not implying that you're wrong, I'm just curious, because I have alittle knowledge of helis.

What is a BF vietnam cobra heli?

As the others have stated as well, they don't usually do them and it is very difficult, sometimes deadly. And no inverted flight.

I have seen several pieces of film footage which show the AH-64, AH-1W/Y?? and the British "Lynx" doing a 'roll". I have never seen a helicopter do a "loop", but I suspect the AH-64 could do it, but I also suspect that it is a "prohibited" manouver(sp).
From first hand experience, I know a competent pilot could get an AH-1G inverted in a "split-S" and recover. I have photos to prove it which I will post if there is an interest.
The crew chiefs hated it when we did it because the oil bladder in the pylon would empty all over the inside of the engine/transmission area and make a bloody mess.
Sorry 'bout that Phillepe, Axe, and Grit.

Seen them do rolls and some other tricky aerobatic's, but never seen them fly upside down for more then a second or two, know of two pilots that tried it once, it killed them when they couldn't recover and hit the ground from 5,000ft

I saw a Sikorsky testing film from the early 60's in which they took a stripped down CH-53A to do a set of barrel rolls and a loop. Sure enough they did it, but According to the film, the airframe had to be retired.

oh, then is the for-a-fewseconds-upside-down-flight thing on the BF vietnam cobra heli incorrect?
I'm not implying that you're wrong, I'm just curious, because I have alittle knowledge of helis.

Nope, some can doo tight loops, but they pretty much fall over in a controlled fall when they reach the apex and it takes a good pilot to get them recovered back to normal flight.