Caco's trial helicopter flight.....

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CharlieOneSix
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Re: Caco's trial helicopter flight.....

#161 Post by CharlieOneSix » Sat Oct 13, 2018 10:53 pm

From the NZ Herald:
Robinson helicopters make up 35 per cent of the New Zealand fleet but 49 per cent of accidents, 64 per cent of fatal crashes and all seven fatal mast-bump accidents.
This safety notice from Robinson is quite amazing:
.
rhc44.JPG
rhc44.JPG (16.34 KiB) Viewed 770 times
From the document below: The low-G mast bumping accident rate in New Zealand compared with the United States is about nine times higher.
New Zealand Transport Accident Investigation Commission

All quite concerning. You don't get to try recovering from mast bumping in a Robinson - it's a one way ticket to the morgue.
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Re: Caco's trial helicopter flight.....

#162 Post by Seenenough » Sat Oct 13, 2018 11:14 pm

I learned to fly helicopters on an Enstrom 280.It had no governor or corolator and required constant throttle changes for each process .It has a very rugged undercarriage which is designed to deal with very heavy run on landings.Later on in more advanced failure training it gave a lot of leeway to practice many proceedures knowing that the skids could take quite a bit of abuse.

I believe it made me a better pilot because I had to learn to fly doing everything myself.

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Re: Caco's trial helicopter flight.....

#163 Post by FD2 » Sat Oct 13, 2018 11:38 pm

Quite right Seenenough - the Hiller UH12E that C16 and I trained on was similar, with no real technical refinements.

There is a lot of support around the World for a cheap machine such as the Robinson but it is not forgiving of any mis-handling, and is not really suitable for someone who is just out of training and has no real experience - the very market it appears to be aimed at!

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Re: Caco's trial helicopter flight.....

#164 Post by Undried Plum » Sun Oct 14, 2018 12:37 am

Frank Robinson himself has said that he would not want any family member of his to fly as a passenger in one of his helicopters with a pilot who has less than 500 hours in the thing.

Seenenough

Re: Caco's trial helicopter flight.....

#165 Post by Seenenough » Sun Oct 14, 2018 2:06 am

Later on when doing FADEC and govenor failure training on Squirrels I found them easy to to as I to me it was just like fling the Enstom.Small little adjustments from a log way off.The Enstrom also taught me to use throttle to adjust tail torque when landing with no tail authority.Not really possible on B2s but could be done with B3s.

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Re: Caco's trial helicopter flight.....

#166 Post by Cacophonix » Sun Oct 14, 2018 5:02 am

FD2 wrote:
Sat Oct 13, 2018 9:22 pm
There's a trial going on right at the moment:

https://www.stuff.co.nz/national/107499 ... al-resumes

and in general, if you're quick enough to drop the collective in time after the donk stops, you still have less suitable places for your engine-off landing amongst all the rugged countryside.

The R22 is a popular choice for people in remote areas but it's not an ideal beginners' machine....
Sadly I do know of an old school mate's friend, a very good Kiwi fixed wing pilot, mountain pilot and world renowned mountain flying instructor, who was killed in the mountains near Queenstown while flying the R22 as a low hour heli pilot. She was flying back to base after dropping off a fellow pilot on an aircraft pickup and was running late en route home and possibly worried about running out of light in the mountains was flying fast when a clang was heard and a local farmer saw the aircraft drop out of the sky the rotors completely stopped. Light on fuel, at speed in good viz. but with possible mountain tubulence and the pilot possibly distracted it seems that the aircraft suffered some sort of loss of control that resulted in a fatal rotor strike or mast bumping incident.

https://www.nzherald.co.nz/nz/news/arti ... d=10846107

As someone who has elected to learn in the R44 I am aware of many accidents (mostly in the R22 to be fair) and am apt to listen and try and learn from Robinson's training videos and safety notices. I have in effect swallowed the Kool-Aid and the little aircraft is the best thing since sliced bread to me now even if I am still more often than not (but increasingly less so now) a ham fisted fixed wing type who is having to up his game to fly the little beauty.

It seems amongst the helicopter flying cognoscenti the Robinson attracts strong emotions both way and I am apt to listen and learn from both sides of the debate.


As for the Robinson's throttle correlator it really only works in the range between 18 inches and 24 inches of manifold pressure and I am being taught to consistently judge to the amount of throttle to twist on. Nice to have but never to be ignored or blindly relied on.

As for the rest I am thoroughly bought into getting the licence, whatever it takes now. I am just so sorry I didn't do this years ago.

Caco

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Re: Caco's trial helicopter flight.....

#167 Post by CharlieOneSix » Sun Oct 14, 2018 8:32 am

FD2 wrote:
Sat Oct 13, 2018 11:38 pm
Quite right Seenenough - the Hiller UH12E that C16 and I trained on was similar, with no real technical refinements......
I think FD2 mentioned in an earlier post somewhere about how counter-intuitively you had to wind off throttle in a Hiller UH12E as you raised the collective before opening it again before you took off.

I loved flying the Bell 47J2 - just as basic as my first car, an A35! On 11kv power line flying you didn't have much opportunity for looking inside but it soon became easy to keep the engine rpm, and therefore the rotor, within the permitted 200rpm band by sound alone, 3000-3200rpm if I remember correctly - it was a long time ago.

The Enstrom was a great machine - I only had one trip in it when I went for a job interview with Twyford Moors Helicopters in 68, wish it could have been more but I declined the job offer.
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Re: Caco's trial helicopter flight.....

#168 Post by Cacophonix » Sun Oct 14, 2018 6:11 pm

I wonder if anybody here ever got to fly one of these?



https://en.m.wikipedia.org/wiki/Saunders-Roe_Skeeter

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Re: Caco's trial helicopter flight.....

#169 Post by Cacophonix » Sun Oct 28, 2018 12:21 am

I was wondering whether or not it was generally possible to recover from a tail rotor failure when hovering out of ground effect or moving at high speed at low altitude.

The Robinson emergency procedure implies not?
LOSS OF TAIL ROTOR THRUST IN HOVER
Failure is usually indicated by nose right yaw which cannot
be stopped by applying left pedal.
1. Immediately roll throttle off into overtravel spring and
allow aircraft to settle.
2. Raise collective just before touchdown to cushion
landing.
This seems imply an autorotation with a yawing or even spinning body! Have I missed the point?

Rolling off the throttle should reduce the effect of torque but the aircraft will still tend to yaw under the influence of the previous yawing momentc so the best that seems possible is a successful yawing autorotation and the hope that the aircraft doesn't roll over which is likely at speed.


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Re: Caco's trial helicopter flight.....

#170 Post by FD2 » Sun Oct 28, 2018 4:29 am

Caco -

there's a lot more theory than practical knowledge about this subject, thank goodness! Remember that the only 'stability' in a helicopter is a partial one in yaw, solely due to airflow over the tail pylon in forward flight. I'm talking about a machine with no artificial stability assistance. The Robinson does not have much of a surface area to its tail pylon, like many other helicopter designs, so it is probably not possible to keep it even half cocked in one direction with a tail rotor failure. The more surface area there is behind the rotor centroid compared to that in front of the centroid, the better off one is, in theory.

Best have a chat with your instructor about that one! At least one has a fighting chance with tail rotor control failure...Also think about flying inside the 'Deadman's Curve' parameters at low level, which cover the engine failure case in ideal conditions, without the added 'confusion' caused by a tail rotor problem.

In the hover, you should be able to cushion the touch down and you will probably decrease the rate of rotation but not stop it entirely before reaching the ground and any drift may cause the aircraft to roll over as will the chance of the undercarriage collapsing. :(

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Re: Caco's trial helicopter flight.....

#171 Post by Cacophonix » Sun Oct 28, 2018 6:04 am

FD2 wrote:
Sun Oct 28, 2018 4:29 am

Best have a chat with your instructor about that one! At least one has a fighting chance with tail rotor control failure...Also think about flying inside the 'Deadman's Curve' parameters at low level, which cover the engine failure case in ideal conditions, without the added 'confusion' caused by a tail rotor problem.

In the hover, you should be able to cushion the touch down and you will probably decrease the rate of rotation but not stop it entirely before reaching the ground and any drift may cause the aircraft to roll over as will the chance of the undercarriage collapsing. :(
Many thanks for the detailed comment and advice. Always good to get such gen. from a helicopter pro. like yourself FD2. I will, as you suggest, speak to Phil as well.

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Re: Caco's trial helicopter flight.....

#172 Post by Cacophonix » Mon Oct 29, 2018 2:26 pm

LTE - Loss of Tail Rotor Effectiveness

http://www.dynamicflight.com/aerodynami ... _tail_eff/





:-?

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Re: Caco's trial helicopter flight.....

#173 Post by CharlieOneSix » Mon Oct 29, 2018 3:30 pm

Caco - well done for posting those videos!. You can see how my theory in post #36 on the King Power thread possibly fits.

In the first video on LTE theory I have to say that in 38 years of flying helos I have never heard the term "tail rotor vortex ring state"!!! What about you, FD2? Caco - have a word with Phil about that! Maybe it's been discovered since I retired in '99!! :)) I think this side of the pond we just lump it in as LTE. However Ray Prouty does describe it here in Rotor & Wing:

Ask Ray Prouty...

The LongRanger accident video certainly looks like LTE. He should have reduced collective as soon as he could and stuffed the nose down. Not sure what he was trying to achieve.

I've only run out of tail rotor authority once - in a Bell 47J2 whilst climbing slowly up a steep Welsh hillside at about 30ft AGL whilst inspecting an 11kv power line. The left pedal hit the stops but I was able to kick on right pedal and throw the helicopter over my right shoulder and dive away down the hill. Sweaty moment though, not to be repeated! #:-S
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Re: Caco's trial helicopter flight.....

#174 Post by FD2 » Mon Oct 29, 2018 6:58 pm

Nope - never heard of TR Vortex Ring - it must be a new thing.... :-?

The LTE mention reminded me of one or two videos I'd seen where the pilot has run out of tail rotor thrust - both Skycrane firefighting machines and both recovered successfully after some brown trouser moments. Here is one:



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Re: Caco's trial helicopter flight.....

#175 Post by G~Man » Mon Oct 29, 2018 11:08 pm

B-) Life may not be the party you hoped for, but while you're here, you may as well dance. B-)

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Re: Caco's trial helicopter flight.....

#176 Post by Cacophonix » Tue Oct 30, 2018 8:55 am

Looking at those videos of the Skycranes, it seems that soon as one of those long helicopter tail booms starts swinging under torque in the opposite direction to those long, relatively heavy, rotors then you are in the land of angular momentum and a lot is left riding on the small tail rotor whose thrust, may have been compromised by the wind or ingersion of the vortices, and a boot full of left pedal to save the day. Looking at both videos it seems like the pilots ran out of pedal but had enough height to push the cycle forward and get some forward speed and gain enough airflow to allow to sabilise and allow recovery, both remarkably close to the ground.

Hair raising stuff!

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Re: Caco's trial helicopter flight.....

#177 Post by Cacophonix » Thu Nov 01, 2018 4:04 am

The Robbie will autorotate with zero speed.

However I see that recovering from a Zero speed 360 degree autorotation is not without its dangers, my training outfit having lost a R22 in just such a training exercise back in 2015 when the skids dug into a ploughed field and the helicopter rolled over after difficulties in recovering from a 360 autorotation, probably due to windshear.

https://www.gov.uk/aaib-reports/aaib-in ... eta-g-thla

Enough to dent one's confidence, just before a GFT. The aircraft was written off apparently.

Example of a 360 autorotation lesson lesson here.



As ever the USA folks go for a landing on the hard surface whereas all such training at Headcorn, perforce (tis a grass field) lands onto grass.

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Re: Caco's trial helicopter flight.....

#178 Post by Cacophonix » Thu Nov 01, 2018 4:32 am

Perhaps the R44 gets a bad rap from the press... and it is definitely not an R22.
Flight Handling

The R44 was given high marks for its manners in the air. Pilots with time in the Bell JetRanger insist that it handles more like that aircraft than the Robinson R22, calling it stable, smooth and "not squirrelly."

Turns don’t feel forced, nor do pitch changes, allowing the aircraft to be maneuvered around a point or held on glide slope almost effortlessly. "It feels like you’re wearing it," commented one high-time R44 pilot. "Just think about what you want it to do, and she’ll do it," said another.

Many people attend the Robinson R44 Pilot’s Course, a transition school, so to speak, designed to give both novice and experienced pilots extensive, hands-on training in the aircraft. Factory instructors give each student several opportunities to perform autorotations in company trainers, so they can become familiar with the aircraft’s temperament in the unlikely event of an engine failure.

Pilots are surprised to see how gently the R44 glides to the ground during an autorotation, as well as how relatively easy it is to keep the rotor system "in the green" from start to finish. Students quickly learn that the R44’s semi-rigid, tri-hinge rotor system can store enough inertia during descent to allow the pilot to do a full-touchdown autorotation, then raise the collective, fly another 10 feet, and do a second nicely cushioned touchdown without bringing the engine back online.
https://www.rotorandwing.com/2009/06/01 ... inson-r44/

Next lesson on the 7th (a whole week away)! :(

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Re: Caco's trial helicopter flight.....

#179 Post by CharlieOneSix » Thu Nov 01, 2018 9:18 am

A 360 autorotation is a good training exercise but in a real life engine failure situation with the most suitable field underneath me I would prefer to S turn whilst drifting a little downwind. By doing that I would keep the landing area in sight at all times rather than turn my back on it.
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Re: Caco's trial helicopter flight.....

#180 Post by FD2 » Fri Nov 02, 2018 10:30 pm

Caco - some of this may sound a bit negative but better forewarned and forearmed. The R44 sounds like an improvement on the R22 and, I'm guessing here, has higher inertia in the blades than the R22?

It's not an easy process, even converting with a lot of fixed wing experience. It opens up a whole new world of things you can do in the air but it will all come together as you gain experience.

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