cna helis fly upside dow and stay that way?
i know r/c helis can, because of the rotor blade angle but I don’t knoe about the real ones[?]
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.
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.
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.
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 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.
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.
(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.
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
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.
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).[:D]
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.
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!
yes Battle Field Vietnam
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.
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.
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
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
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!