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Barrel rolls with a huey ? is that possible IRL ?


FZG_Immel

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Tonight I was in some aerobatic server, and out of being bored, i started trying some crazy stuff with the huey.. I can safely make barrel rolls with the huey. Is that something that is even possible IRL ?

 

very smoothly done in the sim, it creates no problems.


Edited by FZG_Immel

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Any positive G maneuver within reason is possible, as long as it won't make the rotor blades collide with tail boom (aggressive pull-up, or roll to the left), or go well above Vne (danger when looping a helicopter). Just keep it light.

 


Edited by Sundowner.pl

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I don't know if it is possible in real world heli's but I've done similar type maneuvers with my RC heli's that were not designed for it and others which were not setup as 3d models. Even though the models aerodynamics are somewhat removed the from real world aircraft the moving parts(rotor head assembly,swash plate etc.) are pretty much the same. So while undoubtedly far from recommended it might be possible but I have never heard of it being done in any helicopter.

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You mean, like that:

 

 

:smilewink:

 

BTW, Nick Lappos wrote few things about aerobatics in general few years ago:

Regarding aerobatics in non-aerobatic machines:

 

1) Don't do them unless you have the skill and a special dispensation from the

Pope.

 

2) Fear airspeed build up while pointed at the farm. Mcbloo is dead on,

airspeed buildup is a real problem. With your nose 90 deg down, you will

build speed like a Mosler safe, so plan the maneuver to get 90 nose down while

real slow and get the nose back up fast. Load factor is caused by pitch

attitude rate and airspeed, so the penalty of waiting a few seconds before

pulling out is that the pitch rate to get the nose level causes a lot more

g. Since the load factor of the rotor reaches a max at about 80% of Vne, if

your speed builds too fast, you're sunk, cause you will stall the rotor trying

to raise the nose. This is kind of what happened to Egyptair, where he got so

fast it was actually unrecoverable (mach effects in his case).

 

3) Avoid wasting load factor while pulling out. Keep the wings close to level,

so all your rotor's poop is working to get you back to level flight.

 

4) When you ask too much from the rotor, it mushes through, and you get an

attitude change but your flight path is still unchanged. This means you'll

still hit, but you'll be looking at sky while doing it. Stall will limit the

load factor, and may cause high vibes and sloppy roll control. In older

machines (50's vintage) you may accidentally perform the classic pitch up and

roll left retreating blade stall maneuver, accompanied by control feedback).

In this hairy flare, you might actually autorotate the rotor, and will need to

pull collective to keep the rotor speed somewhere on the gage.

 

5) Most helos have lots of static structural strength (static structure is the

non-spinning kind, everything from the tranny down), with that stuff designed

to take what the rotor can dish out. The weak link is usually the rotor, and

the controls. When you get control feedback, you are actually back driving

the servos, which means they are putting out max force, and the rotor is

pushing them backwards, making your controls pulsate. Imagine that you park

your machine up against a concrete wall, and cast the rotor blade into the

wall with extra concrete. Then you put hydraulic power to the servos and

start playing with the control sticks, making the blade, horns, push rods,

swash plate, and servos take the beating because the rotor blade is stuck in

the wall. Ouch! That's what happens to a helicopter when you push it around

too much. All this assumes you have a certified helicopter, where someone,

Military or FAA, has setsome standards as to the strength and servicibility of

these systems. For experimental kit builts, there really are no standards,

and therefore no real assurance of anything. Let the buyer beware, with a

parachute.

 

6) The loop is the worst maneuver to try since the critical place is when you

run out of airspeed at the top, where there is little you can do if you

misjudge except try to roll off the maneuver. If you start falling through,

the cyclic will be less effective, or maybe ineffective, and you'll become a

passenger. The next bad place is when you are staring at houses over the top

of your glare shield, and your airspeed is going rapidly beyond Vne.

 

7) The worst rotors for aerobatics are teetering ones, since they rely on

positive load factor to stay together and to provide cyclic control power. The

literally give you no out if something goes wrong. Recall that mast bumping

can occur, especially when you put big cyclic denands in when the load factor

is low. Most articulated rotors hold good roll and pitch control power down

to zero g or even lower, and rigid rotors are even more forgiving, but

teetering rotors will not only lose control, they may help you sever the mast

at the wrong time. BTW, all tilt rotors have teetering rotors, so they can't

be too sporty as helos.

 

 

Some specific comments on the excellent thoughts presented by others:

 

>Ron (Sikorsky fan) said:

"The guy that accidentally put the Jet Ranger into a loop probably didn't

>have to complete the loop, just roll (or pull if you're vertical) to the

>nearest horizon....."

Good escape technique, as long as there is positive G to work on. Pull

collective and keep back stick in to keep the load factor positive, while

rolling back rightside up.

 

Matthew said: "you have the option of rolling upright and pulling out if your

speed looks like it would be too great.....(regarding engine failure) .I'd

guess that with sufficient airspeed, aft cyclic would keep your rotor spinning

for some time. Use the collective to control your Nr."

 

Sounds right to me. The worst luck on earth is to lose your only engine right

there at the top of a loop. Maybe it just isn't your day.....

 

Bob Barbanes said: "Guys, guys, guys...ANY helicopter can be looped, provided

that positive-G was maintained throughout the maneuver."

 

Maybe so, but the need for enough speed to get you through the first 90

degrees of the pitch up might be hard to attain in some machines. Of course,

if you pitch up really fast, you don't need any speed. I rode thru a partial

loop from a hover in a BO-105, as I described in a post above.

 

Nick Lappos


Edited by Sundowner.pl

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(...) So while undoubtedly far from recommended it might be possible but I have never heard of it being done in any helicopter.

 

Don't know what the manual says about it but I have seen a Bo-105 do it.

 

Here's a vid (not mine):

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Yeah, that's nice but I'll bet his gunner can't hit the broad side of a barn while he's flying like that! :P

 

 

 

Seriously, that is amazing. Thanks for posting. :thumbup:

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Just for the fun of it, I tried doing a looping with the Huey the other day.

 

Well, it doesn't look like a proper circle (the top is more like a cone ;) ), and you drop altitude like crazy (so start high enough), but the Huey does the flip.

 

I won't speculate about the accuracy of the maneuver compared to real life, but it was fun to try anyway.

 

 

Also, Immelman - not so much :D

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One of the main differences between the Helo's in the Vid's doing rolls and the UH-1 is the Helo's in the Vids have Pressurized Hydraulics including the reservoir, I do not believe the UH-1 has a pressurized system like the H53 has.

 

The other factor affecting real life is once you stressed the airframe to that point it would be good for nothing but static display.

The H53 you see in the video was an A model marine bird pulled right from the flight line. After the aerobatics the airframe was retired because of being over stressed at Main GB bolting points and center frame section.

It was used for Training... we use to call it "Alfie"

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Overall the UH-1 is pretty poor platform for aerobatics:

- the teetering rotor restricts maneuvers (only rolls to the right, only maneuvers above 0.5G)

- it's sloooooow, to do a proper loop, you need to get the helicopter going 130-140 kts, that's above its Vne. On the roll-out you would hit 140-160kts, and that's crazy town for its rotor system. Can be done on Bell 412, not really on 205.

 

It does have a lot of power for its weight though... not like the Tarhe, that empty, could power out of VRS, but not to shabby either.

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Helicopters with teetering rotor systems can't do aerobatics. If you do, and for some reason surviva, you can scrap the aircraft. Helicopters with rigid rotor systems, like for instance the Bo-105 and AH-64, can do aerobatics. It's all about rotor system design.

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Overall the UH-1 is pretty poor platform for aerobatics:

- the teetering rotor restricts maneuvers (only rolls to the right, only maneuvers above 0.5G)

- it's sloooooow, to do a proper loop, you need to get the helicopter going 130-140 kts, that's above its Vne. On the roll-out you would hit 140-160kts, and that's crazy town for its rotor system. Can be done on Bell 412, not really on 205.

 

It does have a lot of power for its weight though... not like the Tarhe, that empty, could power out of VRS, but not to shabby either.

 

I hit 160 knots once...the rotor detached, but other than that everything went ok... :pilotfly:

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Depends on your understanding of "aerobatics". You can do barrel roll (to the right only), lazy split-S, and hammerhead - so its up to anyone to judge if that's enough to call it aerobatics-capable.

 

You shouldn't do it, but you can.

 

Well... With my understanding of helicopters, I don't think you can. Maybe you can once, but you'll crash or you can scrap the aircraft. So I wouldn't call that aerobatics capable. And there are several definitions for aerobatics, but I guess the most common one is all abrupt attitude change, pitch more than 30 degrees up or down and bank angles of 60 degrees and more are considered aerobatics.

So yeah, you can probably make 90 degree angle of bank turns in the Huey, but anything inverted, nah, forget it.

Don't forget it's the main rotor system carrying the whole Huey. The fuselage just hangs underneath the rotor system. I don't know if the Huey can keep enough positive G's throughout manoeuvres, but hey, there's a reason you can't find any Huey aerobatics videos on Youtube :)

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A Huey can go past 90 degrees angle of bank if you keep the disc loaded with collective and aft cyclic.

 

However the -10 prohibits intentional maneouvres beyond attitudes of +/- 30 degrees in pitch or +/- 60 degrees in roll.

 

Thankfully not all users used direct copies of the -10 as wingovers to ~110 degrees were common in my old squadron.

 

- Bear

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Just countering claims of "can't" and "scrap the aircraft".

 

- Bear

Pacifism is a shifty doctrine under which a man accepts the benefits of the social group without being willing to pay - and claims a halo for his dishonesty.

 

- Robert A. Heinlein

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It's OK saying it is not aerobatic, but the real question is: what is the maximum permitted *intentional* loading of the rotor system (I'm not talking theoretical maximums - I mean what are you allowed to pull in normal ops that means you can fly it again later)?

 

It's like the Boeing test pilot who barrel rolled the 707 - it was a 1 g maneuver, so no harm to the aircraft whatsoever.

 

I get the impression that +2 g is pushing things in the Huey...

 

Another important factor in any flying is to fly smoooooooooth.

 

Best regards,

Tango.


Edited by Tango
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I don't think a G load is what you should be worry about in a helicopter, what barrier you will encounter first is retreating blade stall, and this can be very painful in the Huey (main rotor blade impacting tail boom). For more lengthy discussion on the subject I would recommend reading this thread on PPRuNe Forum:

 

http://www.pprune.org/rotorheads/447900-helicopter-g-limits-manoeuvering-speed-r22-takeoff-w-gs.html

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I got told by a real pilot that it was possible and only really ever done by a special breed of helo pilot with balls and nerves of steel.

He went on to say there are alot of variables involved in what is a fairly simple manouver in an airoplane to getting it to work in a helo.

And your multi tasking skills have to be on the ball.

He said get it wrong or stay upside down to long then the blades will just fold in on themselves.

He also said its best to practice this in a simulator as in the real world enviroment you could destroy the helo.

Eagles may soar high but weasel's don't get sucked into jet engines.

 

 

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