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Tail Rotor failure option


Nightwolf

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I decided I wanted to practice some tail rotor loss scenarios in the Huey and to my surprise, there is no failure option for it! The only failure related to tail rotor is a gearbox chip, and as far as I can tell it has no effect on actual operation. I feel like it's important to be able to practice tail rotor loss and recovery especially for a combat aircraft where it is much more likely to occur.

 

Is it possible to add a triggerable failure such as a tailrotor gearbox failure similar to the main gearbox failure to the Huey? That way people can practice recovery and landing without having to work very hard to hit the tailrotor on a tree or building or the ground without damaging the rest of the helo just to have a nonfunctioning tail rotor.

"Fighter pilots have ice in their veins. They don't have emotions. They think, anticipate. They know that fear and other concerns cloud your mind from what's going on and what you should be involved in." -Buzz Aldrin

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I want this too, but I don't expect much. They say they are finishing up multicrew and there was talk last year of re writing the engine and rotor blade code. It is an old module that isn't new hotness, so I just enjoy it as is (which is very good mind you) and expect no more updates.

 

If they do add something then I'll be surprised ;)

 

 

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As much as I would like to have additional training options, I'm afraid this one is not so easy.

 

The complete tailrotor gearbox failure doesn't leave you much options anyway beside cutting the engine and entering autorotation.

 

More interesting from my point of view would be the option to simulate "stuck pedals" at different positions e.g. high power/ low power of different magnitudes.

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Well for the stuck pedal, I guess you can just push your rudder full left or full right and just leave it there, no?

 

Yeah this works and it's what I am doing now.

 

Still if we dream about tail rotor failure options I was thinking to throw this one in.

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As much as I would like to have additional training options, I'm afraid this one is not so easy.

 

The complete tailrotor gearbox failure doesn't leave you much options anyway beside cutting the engine and entering autorotation.

 

Well not necessarily, right? Especially at higher speeds and altitude it's possible to use the weathervane or airframe keel effect to keep the helicopter oriented, right? (I'm definitely no helicopter expert) I'd think that especially for combat helos, as long as the main driveshaft to the main rotor is intact and you have power to maintain altitude you'd rather not instantly autorotate the second you lose your tailrotor since you're probably over enemy territory. Even at lower altitudes and speeds, I would think you would be able to climb and get altitude, then reduce collective to reduce torque and bank/pitch the helicopter to get airspeed which would then weathervane the nose to the right direction. Then on landing you come in fast, stop fast, and put down before the rotations get too fast?

 

But then again, this is why I think we need failures like this, and stuck pedal is a good one too. I don't know exactly how the helo will react because I can't make it happen so I can't practice it. The damage model for it is already there, the only thing we don't have is the option to fail it ourselves.

"Fighter pilots have ice in their veins. They don't have emotions. They think, anticipate. They know that fear and other concerns cloud your mind from what's going on and what you should be involved in." -Buzz Aldrin

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I have no problem inducing tail rotor failure, just clip it on a tree or other object and heaps of practice,... :music_whistling:

Control is an illusion which usually shatters at the least expected moment.

Gazelle Mini-gun version is endorphins with rotors. See above.

 

Currently rolling with a Asus Z390 Prime, 9600K, 32GB RAM, SSD, 2080Ti and Windows 10Pro, Rift CV1. bu0836x and Scratch Built Pedals, Collective and Cyclic.

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Then on landing you come in fast, stop fast, and put down before the rotations get too fast?

 

Your approach works on certain types depending on how much altitude and speed you got to start with. But you wouldn't stop but rather run it on to a flat surface between 80 and 110 knots depending on weight and wind.

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It's a shame we can't fail the tail rotor drive, but we can simulate the various scenarios to some extent.

Stuck or limited control is simulated IRL by just locking your feet in position and performing a run on landing at a speed and power combination that you work out at a safe altitude with trial and error before taking it in for landing. Choose a long and wide hard surface if available to prevent rollover if the aircraft starts to turn as you reduce power after landing, not grass.

 

If it's a total loss of tail rotor, it really depends on your flight profile at the time of loss. In ground effect hover, just lower the lever and accept the hard landing, IRL with 2 crew, the non handling pilot would get the engine off if possible.

 

In an out of ground hover, get the nose down and lower the collective, gain airspeed and try to find an airspeed power combination to fly to a safe landing area for an EOL.

 

In the cruise it might not be apparent that the tail rotor has gone depending on your power setting and type of aircraft until you start to slow down and it starts to turn. Look at something like the french design gazelle or 135 with a big fin that's really effective over 65kts.

 

In the worst case an engine off landing is required, hopefully you have found an airfield to land at and got rid of most of your fuel. Pick a landing spot one third of the way along the runway, at 1200 feet above the runway elevation at 90kts and into wind, lower the collective fully, switch off the engines, aim for around 65kts, control the rotor speed with the collective. As you pass through around 80 feet start to flare the nose up with back cyclic to reduce speed and rate of descent, at around 20 feet check the rate of decent with up collective and forward cyclic and cushion the touchdown with full collective. Do not try to come to a hover or zero speed landing. Let the aircraft run on and keep it straight with cyclic., do not lower the collective abruptly to prevent digging in. It won't be pretty but just concentrate on looking ahead to the end of the runway.

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Thank you Oldahpilot for your well formulated post. You clearly have a lot of experience to share and I am happy to read more about it.

 

I heard the story of the Gazelle which lost the TR drive and realized it only half an hour later.

 

For the DCS Huey I would really like to see anyone demonstrate a power on landing with a clipped tailrotor.

 

I had to try few times after coming too close to a tree/fence/ground during hard quick stops and it was always a huge relief flipping that fuel cutoff switch after spinning few times all around the place.

 

In the DCS Gazelle it would actually be really helpful to have a manual TR drive failure mode as I have not managed yet to fail the fenestron otherwise.

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Thank you Oldahpilot for your well formulated post. You clearly have a lot of experience to share and I am happy to read more about it.

 

I heard the story of the Gazelle which lost the TR drive and realized it only half an hour later.

 

For the DCS Huey I would really like to see anyone demonstrate a power on landing with a clipped tailrotor.

 

I had to try few times after coming too close to a tree/fence/ground during hard quick stops and it was always a huge relief flipping that fuel cutoff switch after spinning few times all around the place.

 

In the DCS Gazelle it would actually be really helpful to have a manual TR drive failure mode as I have not managed yet to fail the fenestron otherwise.

 

You're welcome Gazpad.

 

I currently fly the EC135P2 (now airbus) which has a massive shaped fin, you can really feel its effect. No tail rotor failure with it yet, in fact the only total tail rotor failure I've experienced apart from in the sim was a Lynx Mk7 in the hover taxi, we landed upright after a full rotation, co-pilot got the ECLs back (throttles) and we walked away so it was a good one.

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You're welcome Gazpad.

 

I currently fly the EC135P2 (now airbus) which has a massive shaped fin, you can really feel its effect. No tail rotor failure with it yet, in fact the only total tail rotor failure I've experienced apart from in the sim was a Lynx Mk7 in the hover taxi, we landed upright after a full rotation, co-pilot got the ECLs back (throttles) and we walked away so it was a good one.

 

The Lynx story sounds like it might have slightly raised your heartbeat when it happened. :smilewink:

 

For the stuck pedal exercise, might sound stupid but i really need to focus (too much:doh:) to keep my feet still to simulate it. Otherwise I get that "Forget what my feet are doing" effect and just move them automaticaly where they dont belong for the exercise.

 

So a little support from the Sim would help here... It's great to practice "no pedal" takeoff and landings already though. :joystick::pilotfly:

 

Will have to demonstrate stuck pedal soon on checkride on H269...

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Just back into an object (mostly) works for Mi8, Huey and Gaz. :music_whistling:

Control is an illusion which usually shatters at the least expected moment.

Gazelle Mini-gun version is endorphins with rotors. See above.

 

Currently rolling with a Asus Z390 Prime, 9600K, 32GB RAM, SSD, 2080Ti and Windows 10Pro, Rift CV1. bu0836x and Scratch Built Pedals, Collective and Cyclic.

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Just back into an object (mostly) works for Mi8, Huey and Gaz. :music_whistling:

 

Well A) That's not something I want to get into the habit of doing :lol:

 

and B) That's not very reliable (often also lose main rotor), isn't necessarily easy, and also means you can only experience the failure starting from a very small flight envelope

"Fighter pilots have ice in their veins. They don't have emotions. They think, anticipate. They know that fear and other concerns cloud your mind from what's going on and what you should be involved in." -Buzz Aldrin

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Well A) That's not something I want to get into the habit of doing :lol:

 

and B) That's not very reliable (often also lose main rotor), isn't necessarily easy, and also means you can only experience the failure starting from a very small flight envelope

 

No one said it was perfect with some skill you'll get it, you don't need to put the heli in R for race and plant the boot a gentle approach is best. Besides get creative dink the tail rotor on a tall building, landing on those cranes in NTTR or on top of those tall buildings there is always something to try.

 

:P:thumbup:

Control is an illusion which usually shatters at the least expected moment.

Gazelle Mini-gun version is endorphins with rotors. See above.

 

Currently rolling with a Asus Z390 Prime, 9600K, 32GB RAM, SSD, 2080Ti and Windows 10Pro, Rift CV1. bu0836x and Scratch Built Pedals, Collective and Cyclic.

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In the Huey, that tiny tail fin isn't sufficient to keep the aircraft flying with a loss of tail rotor, even in cruise flight. Thankfully I've never experienced one, but when we run the scenario in our sim, the aircraft immediately veers right and tucks the nose (simulating the change in C of G from the weight of the tail rotor departing the aircraft).

 

It is extremely hard to recover unless you immediately drop the collective and roll off the throttles into autorotation. Perhaps there would be scenarios of low power settings (ie descent) at high speeds where it would be marginally controllable, but maintaining cruise flight or a climb isn't going to happen! Our current fleet has only had a few cases of this, all resulted in very hard landings / crashes.


Edited by Sandman1330

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From memory, the Flight Manual said continued flight to a suitable location was possible above 40 kias.

 

That was for a loss of TR drive, not for actual loss of the TR components.

 

A lot less torque in the -1H than the 412.

 

Don't remember a checklist action for loss of TR components such as rotors, hub and gearbox...

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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From memory, the Flight Manual said continued flight to a suitable location was possible above 40 kias.

 

That was for a loss of TR drive, not for actual loss of the TR components.

 

A lot less torque in the -1H than the 412.

 

Don't remember a checklist action for loss of TR components such as rotors, hub and gearbox...

 

If it's possible, it would be a heck of a ride!! Our checklist is the same for loss of drive as well as components (we just call it loss of tail rotor thrust). The only real difference is the change of C of G causes a nose tuck if you lose components since the moment arm is so long.

 

Edit: Just found a UH-1H flight manual online, you're correct - it states the following:

 

9-21. Complete Loss of Tall Rotor Thrust This situation

involves a break in the drive system, such as a severed

driveshaft, wherein the tail rotor stops turning or

tail rotor controls fail with zero thrust a Indications.

(1) In-Flight.

(a) Pedal input has no effect on helicopter

trim.

(b) Nose of the helicopter turns to the right

(left sideslip).

© Roll of fuselage along the longitudinal

axis.

(d) Nose down tucking will also be

present.

WARNING

At airspeeds below 30 to 40 knots,

the sideslip may become

uncontrollable, and the helicopter will

begin to revolve on the vertical axis

(right or left depending on power,

gross weight, etc.).

(2) Hover.

Helicopter heading cannot be controlled with pedals.

b. Procedures.

(1) In- Right.

(a) if safe landing area is not immediately

available and powered flight is possible, continue flight to

a suitable landing area at above minimum rate of

descent airspeed. Degree of roll and sideslip may be

varied by varying throttle and/or collective.

(b) When landing area is reached,

AUTORO TATE using an airspeed above minimum rate

of descent

CAUTION

The flare and the abrupt use of

collective will cause the nose to

rotate left, but do not correct with

throttle. Although application of

throttle will result In rotation to the

right, addition of power Is a very

strong response measure and Is too

sensitive for the pilot to manage

property at this time. DO NOT ADD

POWER ATTHIS TIME. Slight rotation

at time of impact at zero ground

speed should not cause any real

problem.

© If landing area is suitable, touchdown

at a ground speed above effective transitional lift utilizing

throttle as necessary to maintain directional control.

(d) If landing area is not suitable for a runon

lancing a minimum ground run autorotation must be

performed, enter autorotation descent (throttle off) start

to decelerate at about 75 feet altitude so that forward

ground speed is at a minimum when the helicopter

reaches 10 to 20 feet, execute the touchdown with a

rapid collective pull just prior to touchdown in a level

altitude with minimum ground speed.

 

Our checklist does call for power reduction to minimum, then autorotation if yaw is uncontrollable - it just always manifests ends up being uncontrollable!

 

There is also one for loss of components - it calls for immediate auto:

 

9-23. Loss of Tail Rotor Components. The seventy

of this situation is dependent upon the amount of weight

lost. Any loss of this nature will result m a forward center

of gravity shift, requiring aft cyclic.

a. Indications:

(1) Varying degrees of right yaw depending on

power applied and airspeed at time of failure.

(2) Forward CG shift.

(3) Abnormal vibrations.

b. Procedures:

(1) Enter authoritative descent (power off).

(2) Maintain airspeed above minimum rate of

descent airspeed.

(3) If run-on landing is possible, complete

autorotation with a touchdown airspeed as required for

directional control.

(4) If run-on landing is not- possible, start to

decelerate from about 75 feet altitude, so that forward

groundspeed is at a minimum when the helicopter

reaches 10 to 20 feet; execute the termination with a

rapid collective pull just prior to touchdown in a level

attitude

with minimum ground speed.


Edited by Sandman1330

Ryzen 7 5800X3D / Asus Crosshair VI Hero X370 / Corsair H110i / Sapphire Nitro+ 6800XT / 32Gb G.Skill TridentZ 3200 / Samsung 980 Pro M.2 / Virpil Warbrd base + VFX and TM grips / Virpil CM3 Throttle / Saitek Pro Combat pedals / Reverb G2

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Tucking can be expected without a loss of components as well. The change in CG exagerates it but most helicopters will tuck the nose if at high speed and very out of trim because of the sideways-ish airflow. Atleast I know a 500 and a 206 will. Never tried it in a Huey.

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in fact the only total tail rotor failure I've experienced apart from in the sim was a Lynx Mk7 in the hover taxi, we landed upright after a full rotation, co-pilot got the ECLs back (throttles) and we walked away so it was a good one.

 

Is that the one RAF made a video about? (Maintenance error and hard pressure due to upcomming excercise, if I recall it correctly ?) I’ve been shown that vid’ a couple of times in my AF.

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[DCS Mirage 2K; Huey; Spitfire Mk IX, AJS 37, F-14, F-18, FC3, A-10 Warthog II and a few more ]

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