Flight Controls

[jay43]

Today during maintance I made short and simple vid about movement of main rotor hub with swashplate. Like i said is the same like on Mi-24 so I thought it may be intresting for You.

 

Very cool I found it interesting nice video.

[AlphaOneSix]

Nice video.

[TimeKilla]

Today during maintance I made short and simple vid about movement of main rotor hub with swashplate. Like i said is the same like on Mi-24 so I thought it may be intresting for You.

 

Make more videos!! :thumbup:

[CYGAN apa.sq]

Make more videos!!

Thanks. I could make more viedo's but only about Mi-24 or Mi-2 .

Unfortunately there's more differences then similars between Mi-17 and Mi-24 .

But if somthing will be good to show in topic about Mi-17 I will do that.

[AlphaOneSix]

Tail Rotor Pitch Limit System SPUU-52

 

The tail rotor normally has a maximum pitch angle of 23°20’. At high air density (low altitude, cool day) this amount of pitch actually has a possibility of overloading the drive system. In order to prevent overloading the drive system, the tail rotor flight controls incorporate a pitch limiting system. This system decreases the amount of pitch available at higher air density. When fully limited, the tail rotor pitch is limited to 17°20’.

 

The system determines air density through the use of an air pressure sensor and a temperature sensor. A feedback transducer sends a signal to the control panel in the cockpit to indicate how far the electric actuator (MP-100M) is extended or retracted. The control panel in the cockpit is used to test the system, as well as visually determine the amount of extension of the actuator. At full extension of the actuator, tail rotor pitch is limited to 17°20’. At full retraction of the actuator, tail rotor pitch is not limited by this system, and can reach its full pitch of 23°20’. If the SPUU-52 system is receiving power, but is in the OFF position, the actuator fully retracts and the red lamp on the control panel lights up.

 

Edited November 13, 2021 by AlphaOneSix

[Suchacz]

Today during maintance I made short and simple vid about movement of main rotor hub with swashplate. Like i said is the same like on Mi-24 so I thought it may be intresting for You.

Oh my god, what a wonderful piece of machinery. We want moaaarrr :D

[AlphaOneSix]

Tail Rotor Pitch Limit System (SPUU-52)

 

Here is a picture of the other side of the system.

 

 

As you push on the right foot pedal, the control rod in the picture above moves downward (increasing pitch in the tail rotor blades). In high density air, the actuator (MP-100M) will be extended, and the rocker and stop will be higher than in the picture. The stop and the rocker are hinged together and held apart with a spring. This is why it sort of looks like Pac-Man or scissors or something.

 

If you push too much right pedal, the bushing will come into contact with the stop. The stop is able to pivot slightly before it hits the rocker, at which point it can no longer move. Also, when the stop pivots onto the rocker, the microswitch is activated. The purpose of the microswitch is to temporarily disable the yaw channel of the autopilot, so the autopilot cannot continue to increase tail rotor pitch once the bushing hits the stop. (The autopilot yaw channel will begin to operate normally again once the stop moves away from the microswitch.) The bushing has a spring on it, so when the bushing, stop, and rocker are all in contact, this spring pressure alerts the pilot that he should stop applying right pedal input. The pilot can overcome some of the limit by pushing past the spring in an emergency, but not in normal flight...the pilot will stop pushing the pedal immediately upon feeling the spring resistance.

 

The feedback transducer is what tells the control panel where to move the actuator indicator (the white bar that moves left to right in the control panel window). When the actuator is fully retracted and no limiting is in effect, the white bar indicator will displace to the extreme left. As the actuator extends and pedal travel becomes more limited, the bar will move to the right.

Edited November 13, 2021 by AlphaOneSix

[AlphaOneSix]

Electromagnetic Brakes and Sprint-Type Feel Mechanisms

 

The lateral, longitudinal, and directional flight controls have mag brakes and feel springs to keep the cyclic and foot pedals in place. When the TRIMMER button is depressed on either cyclic control, all three mag brakes are energized and become free to move. In this way, control forces are removed and there is nor spring force to override to move the cyclic or pedals. When the TRIMMER button is released, the mag brakes are de-energized and no longer move. All cyclic and pedal control movements then must overcome the spring tension in the feel mechanisms.

 

Each spring is set to a different maximum tension, but they all start at 9.1kgf (20lb). This initial tension must be overcome to begin moving the controls. As the controls move further and further without pressing the TRIMMER button, the tension increases in a linear fashion, up to the maximum, as listed below:

 

Foot pedals: 53 kgf (117lbf)

Lateral (left-right cyclic): 43kgf (95lbf)

Longitudinal (fore-aft cyclic): 55.4kgf (122lbf)

 

 

Edited November 13, 2021 by AlphaOneSix

[Silver_Dragon]

AlphaOneSix all that systems has been simulated in detail into of Mil Mi-8MTv2 module or will be simplificated?

[AlphaOneSix]

AlphaOneSix all that systems has been simulated in detail into of Mil Mi-8MTv2 module or will be simplificated?

 

WWWS?

 

What Would Wags Say?

[AlphaOneSix]

Collective Pitch and Engine Controls

 

The collective control, through control rods, connects to both the swashplate (to increase or decrease collective pitch of the main rotor) and to the engines (to increase power as the collective is raised, and reduce power when lowered).

 

Edited November 13, 2021 by AlphaOneSix

[AlphaOneSix]

Collective Pitch and Engine Controls

 

When the collective control lever is moved up and down, the power setting for both engines is increased at the same time and by the same amount. For testing and emergency purposes, there are also two independent engine condition levers provided to allow changing the power settings of each engine individually. The engine condition levers are mounted on the pilot's (left seat) collective assembly only. The co-pilot (right seat) does not have access to the engine condition levers.

 

The collective friction assembly, likewise, only exists on the pilot's collective, although both pilots have a friction release button in order to remove the collective friction force. The amount of friction (without pressing the friction release button) can be adjusted using the handwheel on the left side of the collective friction assembly. Adjusting the handwheel loosens or tightens spring force against a friction plate within the assembly, thereby reaming or adding friction force. Pressing the friction release button on either collective control cause hydraulic pressure to push against the friction plate to remove this friction force.

 

Pressing the collective friction release also disengages the autopilot altitude channel, if it was engaged. If desired, the autopilot altitude channel can be re-engaged after the friction release button is released by pressing the altitude channel button on the autopilot control panel.

 

The collective control also includes a throttle twist-grip. When the throttle is fully opened (twisted to the right, or clockwise looking from behind) the engines are set to automatically maintain the proper main rotor speed. This setting is analogous to the AUTO setting for the throttles in the Ka-50. Turning the twist grip to the left disables automatic rotor speed control and gradually reduces engine power to the idle setting when the twist grip is fully closed (turned to the left).

 

The engine separate condition levers can be moved through a range, and includes three detent positions. During normal operations, the separate engine condition levers are left in their middle position, and engine power changes are introduced using the twist grip throttle and movements of the collective up and down. During emergencies or for testing, each engine condition lever can be moved up or down separately from its central position, with the lower position corresponding to idle power. When moved to the full up position. the engine will produce full power.

 

 

Edited November 13, 2021 by AlphaOneSix

[AlphaOneSix]

Engine Speed Re-Adjustment Control

 

In order to maintain the main rotor RPM within the desired range, both pilots' collective controls include an engine speed re-adjustment control. The switch on the control is spring loaded to its central position. Pressing the switch forward increases main rotor RPM, while pressing the switch to the rear decreases main rotor RPM. This switch adjusts the fuel controls for both engines simultaneously.

 

Edited November 13, 2021 by AlphaOneSix

[AlphaOneSix]

Differences between pilot and copilot collective controls

 

It should be noted that the copilot (right seat) collective control lacks several of the controls available to the pilot (left seat).

 

The following lists the available controls to the pilot. The list items in bold are ONLY located on the pilot's collective control assembly. Items not in bold are available on both collective assemblies:

 

• Collective Control Lever
  
• Throttle Twist Grip
  
• Throttle Twist Grip Friction Adjustment
  
• Collective Friction Adjustment Handwheel
  
• Collective Friction Release Button
  
• External Cargo Emergency Release Button
  
• External Cargo Tactical Release Button
  
• Individual Engine Condition Levers
  
• Engine Speed Re-adjustment Switch
  
• Landing Light Control (there are two landing lights, one for each pilot)
  

Edited July 24, 2013 by AlphaOneSix

[AlphaOneSix]

Engine Shutdown Levers

 

The engine shutdown levers (not to be confused with the engine fuel shutoff valves), are located on the cockpit ceiling above the pilot's seat. When in the aft position, fuel from the engine fuel control is shut off from the engine fuel manifolds. When in the forward position, fuel is permitted to flow into the engine fuel manifolds and into the combustion chambers.

 

Edited November 13, 2021 by AlphaOneSix

[AlphaOneSix]

And since there was so much to cover for flight controls, I feel like I should note that I'm done...with flight controls at least. :D

[Rogue Trooper]

Superb thread!

[SNAFU]

Jepp, thanks for the very intersting insights...

[tusler]

This system looks very similar to the Sikorsky HH-3E I use to work on years ago.:music_whistling:

[thrawn]

Looking at this it looks like there is no governor on the MI-8 and oddly rather than the throttle on the collective it is a switch on the panel? or is there a governor and the switch is just to adjust what RPM the governor tries to hold?

[AlphaOneSix]

Looking at this it looks like there is no governor on the MI-8 and oddly rather than the throttle on the collective it is a switch on the panel? or is there a governor and the switch is just to adjust what RPM the governor tries to hold?

 

There is an electronic governor (which I have not talked about at all yet) as well as a mechanical governor (also have not mentioned it).

 

The controls I've talked about here have nothing to do with the governing of the engine RPM. When the ECL's are in their central detent, and the throttle is twisted full right, then the mechanical governor on the engine fuel control takes care of the engine and rotor RPM. The INCR-DECR switch is just to set what RPM you want the engines to be set to. For example, the nominal RPM for the rotor during fight is 95%. You check this on the ground by pulling in 3 degrees of pitch with the collective. If the rotor RPM is not at 95%, you use the INCR-DECR switch (engine speed re-adjutsment control) to set the rotor at 95%. Then you are done and you do't touch it anymore after that. In most cases, you never have to touch that switch at all, except during testing.

[CYGAN apa.sq]

Defult rotor speed is 95% and during engine speed re-adjutsment control and flight can be perform to down from defult - 89 - 93% and up - 96 - 99%.

For exemple You can also adjust RPM rotor befor takeoff and landing by increase rpm a little bit to prevent drop them when You are heavy load and /or your engines don't have enought power depand on altitude (ex. Afghanistan) or they quite worn. This doesn't mean that you not need worry .... it still be carefull about rotor rpm becouse wrong calculate ladning path and to much and rapid movements on stick and collective make drop rotor speed and short way down.

But also you must remember that you can't adjust during advanced manouvers like during display flight (sorry ... my english could't better explain).

This is all for Mi-24 but they have the same engines system so if something is different on Mi-17 A16 please correct me.

Edited July 26, 2013 by CYGAN apa.sq

[159th_Falcon]

Defult rotor speed is 95% and during engine speed re-adjutsment control and flight can be perform to down from defult - 89 - 93% and up - 96 - 99%.

For exemple You can also adjust RPM rotor befor takeoff and landing by increase rpm a little bit to prevent drop them when You are heavy load and /or your engines don't have enought power depand on altitude (ex. Afghanistan) or they quite worn. This doesn't mean that you not need worry .... it still be carefull about rotor rpm becouse wrong calculate ladning path and to much and rapid movements on stick and collective make drop rotor speed and short way down.

But also you must remember that you can't adjust during advanced manouvers like during display flight (sorry ... my english could't better explain).

This is all for Mi-24 but they have the same engines system so if something is different on Mi-17 A16 please correct me.

 

So what you are saying is that the rotor RPM can be set as required between 89 and 99%.

And it is not recommend to adjust this setting unless the helicopter is either in a hover or straight and level flight.

 

Correct?

[Skulleader]

Hello AlphaOneSix,

 

Great topic, I would like to know if it's possible to found the same book where you show us these photos ?

Is it possible to bought this book ?

A great thanks in advance for all and best regards. Skull

[CYGAN apa.sq]

And it is not recommend to adjust this setting unless the helicopter is either in a hover or straight and level flight.

 

Correct?

Correct .... hover or straight and level flight ...and on the ground.

But like A16 said in practise is almost never use.