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Check of tail rotor anti ice system shows 3rd and 4th section


DeMonteur

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When I check tail rotor anti ice system, lamps indicating activation of rotor deicing section after completing deicing cycle of 2nd section jumps on 3rd section although tail rotor have only 2 sections and also this lamp should jump back on 1st section.

 

Anti ice system: continous working, preventing ice build up. On helos, most often on tail rotor because tge tail eotor is more sensitive to ice( loss of directional control, spinning around -> crasch)

 

Deice system: system that work in cycles. Let the ice form, then deice. Most often on main rotor, because of heavy power demand. Usually cycles between blades, of pair of blades( opposite, for less unbalance).

 

Id guess the mi-8 uses the same as above. If so, deice = main rotor, anti ice tail rotor.

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Check of tail rotor anti ice system shows 3rd and 4th section

 

According to your definition have Mi-8 deice system. Although it is used for prevention as well as for deicing. There is 4 cycling sections on each main rotor blade and 2 cycling sections on tail rotor blades. So if I have set knob for tail rotor, section indicator should cycle between 1st and 2nd section. Just try to wait for 3rd section and then turn knob on tail rotor. Section indicator should show 1st section instead of 3rd as it is now.


Edited by DeMonteur
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According to your definition have Mi-8 deice system. Although it is used for prevention as well as for deicing. There is 4 cycling sections on each main rotor blade and 2 cycling sections on tail rotor blades. So if I have set knob for tail rotor, section indicator should cycle between 1st and 2nd section. Just try to wait for 3rd section and then turn knob on tail rotor. Section indicator should show 1st section instead of 3rd as it is now.

 

Ok, didnt read about the mi-8 deice until now.

 

No, its not rightly understood by you.

 

I found this:

 

https://forums.eagle.ru/attachment.php?attachmentid=127156&d=1447323413

 

The knob you turn should be just for checking the Amphs on each sub system.

You select which sub system to see the current draw on the meter to the right.

 

When you put the anti ice system on, it automatically cycles between the heating elements on the blades. You cannot select what to deice by that knob.

 

The cyclic timer controls the energizing sequence of main and tail rotor heating element sections.

 

The heating element of each blade consists of four sections:

• Upper inboard (Section #1)

• Upper outboard (Section #2) • Front (Section #3)

• Lower (Section #4)

• During operation, the cyclic timer energizes each section in order for 38.5±2 seconds. One complete cycle lasts for approximately 154 seconds.

Each tail rotor blade contains two heating elements made of stainless steel and running the entire length of the rotor blade.

 

• During operation, the cyclic timer energizes each section in order for 38.5±2 seconds. Each section is energized twice during each 154 second cycle. The upper element is energized simultaneously with sections 1 and 3 of the main rotor, while the lower element is energized simultaneously with sections 2 and 4 of the main rotor.

 

So the indication of deice will be for the main rotor blades, but you can understand wich part of the tail blade deicing by looking at the section indication.

 

All clear ?


Edited by Gunnars Driver

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Check of tail rotor anti ice system shows 3rd and 4th section

 

It is perfectly uderstood by me, flight enginieers and lecturers who learnt it this way. Once I personally checked it on real machine because I wasn't sure. That emphasised part talks about internal work of system but not the indication. And indication works the way I explained here. That section lights works according to selection of indication knob setting. So you will go through blades 1-5 of main rotor and it will cycle there through section 1-4. When you set tail rotor, section lights should cycle between section 1 and 2. You simply need explicit check for T/R section deicing to be sure it works correctly.


Edited by DeMonteur
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It is perfectly uderstood by me,

 

I didnt check it out in a real mi-8 but in the original manual.

 

This is the test of MRB:

© Set the LOAD CURRENT (TOK nOTPE6I11TEJlEVI) selector switch alternately to MAIN ROTOR BLADES 1-2-3-4-5 (JlOnACTII1 HECYll.\. BII1HTA 1-2-3-4-5 and read the ammeter to check the cur- rent drawn by each section of the main rotor blade anti-icing system. The hUmberbfsection Undertestis determined by illumination of the SECTION 1 (1 CEKIlIl15'l), SECTION 2 (2 CEKIlIl15'l), SECTION 3 (3 CEKIlIl15'l), SECTION 4 (4 CEKIlIl15'l) lights. The ammeter reading for each section of the main rotor blade heaters should be within the limits of 60 to 80 A.

 

This is the test of tail blades:

 

(d) Set the LOAD CURRENT (TOK nOTPE6I11TEJlEVI) selector switch to TAIL ROTOR (XBOCT. BII1HT). The anti-icing system ammeter readings for the tail rotor blades heaters should be within the limits of110 to 150 A.

 

It doesnt mention the secton check for the tail blades.

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From the DCS Mi-8 manual it indicates that the 4 indicators continue the 4 indicator cycle 1,2,3,4.

 

From the DCS-M-8 manual.

 

attachment.php?attachmentid=206365&stc=1&d=1552620641

 

Sections are energized in cycles by cyclic timer ПМК-21. In one cycle, the cyclic timer

activates heating of every section of main and tail rotors for 38.5 sec and cooling of

them for 115.5 sec (main rotor section) and 38.5 sec (tail rotor section). Tail rotor

heating elements sections are energized in the following sequence: the first sections

of tail rotor blades’ heating elements are energized along with the sections I and III

of main rotor blades’ heating elements; the second sections are energized along with

the sections II and IV of main rotor blades’ heating elements.

 

So according to the above the indicators continue to identify main rotor sections 1,2,3,4 with the timing of the of the tail sections alternating at 38.5 seconds on and off in other words the tail heaters 1 sections correspond with main 1,3 and tail rotor blade heater 2 sections corresponds to main 2,4 respectively.

 

This means if you select tail rotor current you can identify which heater is energised by which lamp is lite and verify operation by observing the current.

 

The Mi-17 seems to be much the same except for the duty cycle timings. The indicated currents for the Mi-17 appear to indicate that tail blade heater blade sections 1 are in all parallel as are blade sections 2 hence higher current per heater section for the tail. :)

 

AlphaOneSix might be able to clarify that

DCS_Mi-8BladeHeaters.JPG.5677bc318a215fe8bd7fa902ca5cd173.JPG


Edited by FragBum
<typo>

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

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

 

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@Fragbum: yup !

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I didnt check it out in a real mi-8 but in the original manual.

 

This is the test of MRB:

 

 

This is the test of tail blades:

 

 

 

It doesnt mention the secton check for the tail blades.

 

I see now. So it is not bug. It is feature. Probably too much code for such a small detail.

 

@FragBum thanks for explanation.

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I see now. So it is not bug. It is feature. Probably too much code for such a small detail.

 

Not really the coding for that functionality would have been trivial, at least at the Boolean logic level. :)

 

As it would also be at the hardware level with some diode gating at the expense of maybe an extra switch contact but unnecessary.

 

The implied logic is correct for the annunciator panel as described without adding additional circuitry.

 

I have no other information between the DCS modelled Mi-8 manual and an Mi-17 manual cica 2007.

 

Perhaps there may be a more recent update to the annunciator panel logic in question?

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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Okay.

 

I will start by saying that I am calling the system anti-ice instead of deice. For this aircraft, the distinction is irrelevant in my opinion. If you turn the system on manually before you get icing, it's anti-ice. If you let it come on automatically after icing is detected, then I guess it's deice. In Russian, it's not called either. It's called "heating".

 

The ammeter has nothing whatsoever to do with the anti-ice system. It just checks the current being drawn by the item selected. The systems works just one way no matter what you have selected on the ammeter dial.

 

Here is the sequence for the rotors when the anti-ice system is turned on:

 

  1. The SECTION 1 light illuminates and the heating elements of section 1 of the main rotor and section 1 of the tail rotor are energized for 38.5 seconds.
  2. The SECTION 2 light illuminates and the heating elements of section 2 of the main rotor and section 2 of the tail rotor are energized for 38.5 seconds.
  3. The SECTION 3 light illuminates and the heating elements of section 3 of the main rotor and section 1 of the tail rotor are energized for 38.5 seconds.
  4. The SECTION 4 light illuminates and the heating elements of section 4 of the main rotor and section 2 of the tail rotor are energized for 38.5 seconds.
  5. Go back to #1.

 

This means that each main rotor section is energized for 38.5 seconds and is de-energized for 115.5 seconds per cycle. Each tail rotor section is energized for 38.5 seconds and is de-energized for 38.5 seconds. The total cycle time is 154 seconds.

 

The position of the ammeter dial has no relevance to this cycle, other than it allows you to see if current is being drawn by various blades/sections for troubleshooting purposes. You can check each main rotor blade individually, because you can change each main rotor blade individually. The tail rotor blades are always changed as a set, so it doesn't matter which particular tail rotor blade may be causing the anti-ice to fail, since all three will be replaced anyway.

 

If you turn the ammeter to the tail rotor position and when the SECTION 4 light illuminates the ammeter drops to zero, that means that section 2 on one or more of the tail rotor blades has failed for some reason. If you turn the ammeter dial to W/S or DUST PROT then it will go occasionally drop to zero normally because those elements de-energize when their respective temperature sensors reach 30 degrees C.


Edited by AlphaOneSix
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I have no other information between the DCS modelled Mi-8 manual and an Mi-17 manual cica 2007.

 

Perhaps there may be a more recent update to the annunciator panel logic in question?

 

Thats why I am writing about it here. From my point of view it is bug. But similar kind of bugs is also usual in these helicopters.

I wouldn't be surprised if this logic is different in each series. Or even pieces.

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Okay.

 

I will start by saying that I am calling the system anti-ice instead of deice. For this aircraft, the distinction is irrelevant in my opinion. If you turn the system on manually before you get icing, it's anti-ice. If you let it come on automatically after icing is detected, then I guess it's deice. In Russian, it's not called either. It's called "heating

 

 

This means that each main rotor section is energized for 38.5 seconds and is de-energized for 115.5 seconds per cycle. Each tail rotor section is energized for 38.5 seconds and is de-energized for 38.5 seconds.

 

Very good for this thread that you controbute ! :thumbup:

 

 

Not important for the thread but anyway:

Because the sections of the rotors dont heat full time, some ice will form on the sections between the cycles, thereby its formally a deicing system by western definition. That doesnt mean it isnt good though. To keep all part of the blades heated all timewould cost a lot more electrical power ( more fuel used, heavier alternators and so on).

 

In western modern helos the common idea is to use deicing on the main rotor but to use anti icing on the tail rotor.

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Can also confirm the DCS Mi-8 anti-ice functionality is as per the DCS Mi-8 manual as well appears to conform to the Mi-17 manual with only differences in timings. See post #7.

 

As did Gunnars in Post #4.


Edited by FragBum
<correction>

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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Timings are the same, I'm not sure where you see a difference. It's not the 115.5, is it?

 

38.5 ON

38.5 OFF

38.5 OFF

38.5 OFF

 

So each main rotor section spends 38.5 seconds on and 115.5 seconds off, for a total cycle time of 154 seconds.

 

Or am I misreading something somewhere?

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Timings are the same, I'm not sure where you see a difference. It's not the 115.5, is it?

 

38.5 ON

38.5 OFF

38.5 OFF

38.5 OFF

 

So each main rotor section spends 38.5 seconds on and 115.5 seconds off, for a total cycle time of 154 seconds.

 

Or am I misreading something somewhere?

 

 

Most probably not. You got it :-)

 

 

I think the OP had misunderstood the funktion of the anti ice panel, section lights in particular.

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This is what I have from "TM 1-1520-Mi-17-10" Dept of the Army 2007

 

2-63.3 Rotor Blade Deice Systems

The main and tail rotor blades have electrical

heating elements to prevent ice build-up on the

blades. The main rotor blades have four heating

elements each. The tail rotor blades have two heating

elements each. The blade heating elements are

controlled by the deice system control box. When the

system is operating, the main rotor blade heating

element sections operate for approximately 13

seconds each, in turn. The tail rotor blade heating

element sections operate for approximately 25

seconds each, in turn. This cycle repeats until the...

 

The only other difference I see is this note here also from the same publication.

 

Standard helicopters are equipped

with the RIO-3 radioactive ice formation warning sensor. The sensor automatically activates the rotor, windshield, and engine deice/anti-ice systems when ice is detected. The radioactive elements have been removed

from the helicopters operated by the

U.S. Army. As a result, the deice and

anti-ice systems on these aircraft operate in the manual mode only

 

I'll just add I am not claiming one or the other to be right or wrong just that there is a difference everything else agrees as to operation, I only included that detail as an observation of available data.

 

:)


Edited by FragBum
<edit>

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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Okay I see. You can ignore that -10 then, because it's incorrect. But that's okay, the U.S. manuals contain a lot of discrepancies like that. In fact, the correct information can be found in the TSMO maintenance manual for the ice protection system, found in TM 1-TSMO-Mi-17-23-1 volume 2. I know very little and have no first hand experience with any Mi-8's prior to the Mi-8MT (called Mi-17 for export). The Mi-17-1V is the export name of the Mi-8MTV-1. All Mi-17's operate as I've described above.

 

As noted with the RIO-3, that was an older, radioisotope-based detector used on early versions of the Mi-8 and Mi-17. I'm not sure when they quit using them, as I have documentation of Mi-8MTV-1/Mi-17-1V with both RIO-3 and SO-121 detectors. All of the Mi-8MTV-1/Mi-17-1V aircraft I worked on had the older RIO-3 installed, but all of our Mi-17V-5's (export version of Mi-8MTV-5), Mi-171's, and Mi-172's have the SO-121 detector set installed. Regardless of the detector installed, the PMK-21-TV cyclic timer energizes the heating elements in the same way and for the same times. Maybe on aircraft prior to the Mi-8MT/Mi-17 they had a different timer, I don't know. I kind of doubt it, but I don't have any documentation on them so I can't be sure.

 

Thank you for your input!

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Okay I see. You can ignore that -10 then, because it's incorrect.

 

 

Yup. A good idea should be to get as close to the manufacturer when it comes to flight manuals. Possibly even in the manufacturers language if possible.

I can think of the Mi-17 original manual but in English. It wouldn't be that impossible that they know what they are writing about but in the translation there will be a way for them to express themselves that makes other people interpret some text different than what the manufacturer did mean.

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