Can an EC135 do a roll or loop
 

With the rotor head on the 135 having no flapping hinge per say but a flexbeam that is outboard of the rotor mast I'd say it has enough authority to do a roll. It will probably create massive stress loads and not something you would want to do more than once before putting the aircraft in the scrap pile but it theory can it be done? Or does anyone have knowledge of airbus flight testing showing that it could or could not be done. This is referencing the crash in Drexel Hill PA with the EC135 and crew reports the aircraft did 2 barrel rolls while on autopilot.

https://cimg0.ibsrv.net/gimg/pprune....123b26e1a5.jpg

You can roll anything...just sayin'.

I was lucky enough in the late 80s to see the AS565 panther do a loop at the factory in Marignane and It was one of the 1st time it was executed live at airshow.
The maneuver was slightly underwhelming as we were all expecting to see a nice round loop, and instead it was basically falling on its tail and recovering.

The point is: in oposition to the BO105 solid machined titaninum head or the lynx all metal head, the AS565 (loop pioneer of the time) is a starflex not as away from the EC 135 flex beams design.

Looping - probably not a big issue - the 135 has a big hinge offset - watch the mast moment as you fly around and do manoeuvres - nothing much happens compared to the loads you can get on the ground unless you pay attention.

Rolling - Think about the resultant forces - the BO105 suffers in the tail rotor and subsequently i would have my concerns with the EC135 in the area of the ring frame.

Get back to us. I'll put the popcorn on.

can't you roll anything once?

Looping and rolling a helicopter puts high stresses on the tail boom and drive shaft - the TR gearbox and hub are big lumps of metal on a long moment arm from the aircraft C of G. Without a g-meter fitted you have little idea what you are doing to the rest of the aircraft.

Could it do it? Sure.

Should it? ........

I seem to recall Alan Bristow claimed to have looped an FH1100 at Redhill after someone joked "if you loop it, I'll buy one". He did - just - and they didn't... Hope it wasn't the one that crashed at the Paris Airshow...

Years ago I displayed the Puma HC1. I was encouraged from above to make it a “dynamic” one, rather than previously where displays had consisted of not much more than a series of wing overs, backwards flight and spot turns. As part of my work up I was required to fly with the previous display pilot, who had not displayed for a few years and he showed me manoeuvres that had been developed by himself and others. We subsequently began to explore the capabilities of the aircraft and got to the point where he became slightly nauseous. After that I was left to it.

Shortly afterwards I attended a very interesting brief given by Westlands, who were developing the Lynx and trying hard to impress potential buyers. With a semi rigid head it was a lot more manoeuvrable than my old Puma and it was being “officially” looped and rolled during displays, all very impressive.

However, the Westlands rep stressed that their display aircraft was being very carefully monitored and major components such as main and tail gearboxes were frequently being changed because of the extra stresses put on them. He made it quite clear that a squadron aircraft should definitely not be flown in this way. I realised right then that above all I needed to be gentle and careful with my aircraft to avoid flying it in a way that was potentially more damaging than it was designed for.

Edit: Good advice because with helicopters it’s relatively easy to get into flight regimes that haven’t been taken into account with regard to component fatigue life calculations.

Unlike some other Puma pilots I have heard tales about:)

…and absolutely not scoring the tail boom with the tail rotor blades….

EC225 looping:


that absolutely wasn’t flown by the Test Pilot on his last ever flight before retirement, as part of a fly past, in front of the customer whose aircraft it was about to become….

PCD,

Definitely not me….and no names mentioned.

Asking for a friend?

I can't imagine a more pointless maneuver for a chopper to do.

If God had meant helos to fly upside down, he would have put the rotor blades underneath!

Mog

Search on YouTube:
Swiss air force: 20 helicopters in the air
5:30 should be a proof good enough:)

I am not allowed to post the link :)

You have probably seen this old video - I wouldn't like being the next up in that one!

can you cite a source for this statement?

The Army Air Corps were looping Gazelles at displays for a number of years before somebody thought to check on whatever passed for the Release To Service in those days. Even the POH clearly stated not to exceed 90 degrees in pitch or roll, but hey, the POH is just like a suggestion, right? I can't remember the exact fallout, but it was quite the task to track down all the airframes that had been looped, and then do the subsequent engineering tear downs to establish how many were bent, buckled or scored. All very embarrassing and quite avoidable. There was also a well known photograph of a Gazelle fully inverted (probably following a roll) against the backdrop of a large TV mast south east of Detmold in Germany, everyone admired it, but nobody ever thought to challenge the how and the why.

I remember seeing one of a Lynx in that position, but not a Gazelle.

An AAC QHI did as many loops in a minute as possible in a Gazelle for a Matthew Kelly TV prog back in the 80s ISTR.

.

There is an early video (1950's ??) of a Sikorsky (S-52 I think) doing a complete loop above the factory property .

.

I’m pretty sure that Sid S@#£&3r spent a fair proportion of his gazelle time upside down.

Please forgive an ignorant question – I know very little of the subtleties of rotary flying – but if it's possible to do a 1G barrel roll in a fixed-wing, isn't it possible to do a 1G barrel roll in a helicopter without stressing either the airframe or the moving parts?

Marginally more gutsy than my Basingstoke Carnival display in 1973!

Mog

It isn't possible to do a 1 g barrel roll in a FW - it's a myth that is perpetuated, and defies the basic laws of physics and motion!

You keep positive g throughout the manoeuvre and acceleration towards the centre of the manoeuvre but it goes more and less than 1g but not into negative figures (unless you cock it up):)

You can "attempt" a 1g barrel roll though - just won't turn out what you expected!

Aero's in a helicopter can be done "within limits" - the issue is Joe Pilot doesn't know what they are as the manufacturer or certification authority does not publish them.

Test pilots are called "test pilots" for a reason and they come in different flavours - Production and Experimental. Production Test are pretty much average Joe and Experimental Test live a bit closer to God than most!

Helicopters mostly if any do not have a large enough thrust margin to create high g loadings. They will just mush or wash off speed.

It's the other bits that most people don't think about that are the issue that maybe cannot keep up with what the aircraft "could do".

i.e. precession loads on the TR, feedback to the MR PCL's, Low or prolonged -ve g on lube, fuel and HYD systems and the list goes on.

For example - everybody knows about HYD "jack stall" in an AS350. Why is it that way? It is to give you a built in warning that you are approaching the feedback limits of the PCL's on the MR.

Dual HYD models have a LIMIT light as the warning as they will not "stall". What happens if you go past the "LIMIT"?. You probably will start bending and breaking stuff.

Operating outside the approved envelope is the territory of ETP's. Joe Pilot doing this stuff proves what exactly? You get away with it once, you get away with twice you get away with it...................................?

And don’t forget that those ETP’s operate dedicated , instrumented aircraft of which the critical parts can be monitored either in the cockpit or in a telemetry room full of engineers who can call “STOP” at any time during those tests…

Looks like 1G to me.

Bell 407 at an airshow in South Africa, circa 2004.

Bell permanently grounded the aircraft (and all components)

All you can tell from the Hoover video is that is positive G, but not how much. It is theoretically possible to maintain a minimum of 1G during the maneuver, but then you will have a maximum of well over 1G towards the end, as you will be in a rapid descent that needs to be arrested.

Exactly. You can’t start and end with 1 g! Newton 2

212man and others - thanks for your helpful comments.

Informative:


The school.

I thought this was a “Professional” Pilots rumour network?

Looping and rolling helicopters have no place or requirement when flying professionally. So any wannabes reading the !!!!e posted in this thread………just don’t!11!

All the warnings about rotor and airframe stress forgetting that if the positive g disappears all the fuel, oil and other juices necessary to keep the cab healthy end up in the wrong place.

Moronic Darwinian selection in action.

DB - do you know what the g limits for your helicopter are?

Is there a specific warning in the RFM about negative g? (other than for Robbies)

You can get negative g in turbulence - does all the fuel and oil disappear then?

No-one has suggested anyone tries this, it was a question worth asking and answering.

Most manuals will prohibit aerobatic maneuvers, they don't go into much more detail, it's not what civvie helicopters were designed to do.
It also looks quite dull, even with Chuck whatsisname in the 105, it's the wrong tool for that job.
If "pulling g" is the objective, choosing rotorcraft will prove disappointing.

I agree Bell_ringer, but DB getting on his high horse about a thread where no-one has suggested just going out and trying such manoeuvres seems rather OTT.

My point to DB was that less than 1g in a helicopter or even negative g doesn't lead to the instant mechanical failure he implied - you can get to negative g without aerobatic manoeuvres as you know.