New pilot. Loss of tail rotor effectiveness in IGE hover below 20 meter.

[DmitriKozlowsky]

New pilot. Loss of tail rotor effectiveness in IGE hover below 20 meter.

In training mission, at times, about half, when hovering or entering IGE hover below 20m, I experience LTE. Rudder control becomes ineffective and often I am unable to re-transition to forward flight due to LTE. But I am unable to understand why I am experiencing LTE. Helicopter is lightly loaded (I change the load out to near empty and lower fuel).

[ARM505]

Some suggestions: - Submit a track of the event if possible if you want other people to attempt to replicate the situation.

- Secondly, open your controls indicator (R CTRL & ENTER) and see if you're actually getting full pedal input at the time - I've personally found the Mi24 to be very odd in this regard. I don't want to say 'bug', but for some reason, especially with the yaw channel engaged, something tends to 'eat up' the full pedal travel, and you'll see that the pedal deflection is either massively reduced from its maximum (despite you having full physical pedal input in), as well as a totally off center neutral position. My understanding of something may well be off, but that's been my experience (it has improved since initial release).

- Thirdly, attempt to replicate the issue with the A/P yaw channel off and see if that isolates the problem (just a hunch)

- Finally, do you have the rudder trim option enabled in the special menu for the Mi24? I'm not sure if this is bugged or not, but there have been some discussions of weirdness in this option, if I remember correctly.

Edited January 20, 2022 by ARM505

[admiki]

40 minutes ago, ARM505 said:

Some suggestions: - Submit a track of the event if possible if you want other people to attempt to replicate the situation.

- Secondly, open your controls indicator (R CTRL & ENTER) and see if you're actually getting full pedal input at the time - I've personally found the Mi24 to be very odd in this regard. I don't want to say 'bug', but for some reason, especially with the yaw channel engaged, something tends to 'eat up' the full pedal travel, and you'll see that the pedal deflection is either massively reduced from its maximum (despite you having full physical pedal input in), as well as a totally off center neutral position. My understanding of something may well be off, but that's been my experience (it has improved since initial release).

- Thirdly, attempt to replicate the issue with the A/P yaw channel off and see if that isolates the problem (just a hunch)

- Finally, do you have the rudder trim option enabled in the special menu for the Mi24? I'm not sure if this is bugged or not, but there have been some discussions of weirdness in this option, if I remember correctly.

 

SPUU 52 will limit right pedal travel to prevent damage to tailboom and TR itself, but that shouldn't be his problem with light helicopter

[Plon]

Try to reset all trim when it's happening, (rudder trim) you may recover some authority on rudder.

[DmitriKozlowsky]

Thank you. I do not use RUDDER TRIM in helicopters. I have UH-1 and Gazelle. I think I am fairly competent in DCS with rotary. Gazelle is like Triumph sports car. UH-1H empty is like a SUV. UH-1H heavy is like a heavy SUV. MI-24P is like a fast heavy sports SUV. When fast its fairly maneuverable. WHen slow, it feels like a heavy truck. It really is a very large helicopter. With translational lift and above 50 kph it , to me, feels like turboprop fixed wing. But that's just me in DCS. In real world, I don't know.

[Grenadey]

2 hours ago, ARM505 said:

Watch this video by Nazradu :

 

In summary, when you end up with the pedals at full deflection due to the Yaw Autopilot then double tap the trimmer button and they will reset to centre.

 

2 hours ago, ARM505 said:

 

 

Edited January 20, 2022 by Grenadey

[admiki]

6 hours ago, DmitriKozlowsky said:

New pilot. Loss of tail rotor effectiveness in IGE hover below 20 meter.

In training mission, at times, about half, when hovering or entering IGE hover below 20m, I experience LTE. Rudder control becomes ineffective and often I am unable to re-transition to forward flight due to LTE. But I am unable to understand why I am experiencing LTE. Helicopter is lightly loaded (I change the load out to near empty and lower fuel).

It would be the best if you could upload track file for us to check it

[cow_art]

Next time it happens, activate Control Indicator (RCTL + Return) and check what happens. My guess would be, that the yaw-autopilot has trimmed the rudder so far to one side, that you have not enough rudder authority left (I think this can happen even when you don't use the DCS rudder trim setting).

 

Edited January 20, 2022 by cow_art

[Grenadey]

As Cow_art says, the Yaw Autopilot will trim and trim and trim until the anti-torque pedals are well over to one side.  The solution is in the video I posted above.

[AeriaGloria]

Yes, everyone is right here about the yaw autopilot trimming the rudder causing this issue, it only trims your rudder if you exceed the 18% authority while the heading hold mode is activated, and heading hold mode is only activated less then or equal to 19-20% input side to side. 
 

one other thing worth mentioning, you can have low flight weight, which is a great first step that you did, but to also remember how slowly the collective needs to be moved. If you increase rotor pitch too quickly before the engines can rev up to maintain rotor RPM, the rotor will produce much more torque then it would if the engines had revved up and used lower collective with less RPM decrease. I’ve heard some people say the tail rotor has to play “catch up.” I think there’s also good reasons behind the idea the tail rotor doesn’t increase thrust as fast with pitch as the main rotor does, owing perhaps to its 5-6x faster RPM. 

For the engine it takes 8 seconds to go from flight idle to full, and 4 seconds to rev up from cruise. So I recommend being close to that and you should have some benefits even outside of your immediate situation.

 

On release many people speculated it had a simulation of one cause of Loss of Tail rotor Effectiveness, LTE, where the tail rotor would VRS like the main rotor if doing a slide to the right. But I have either not experienced that in awhile or not been in a situation that triggered it. 
 

hope some of that helps 

[DmitriKozlowsky]

Ya'know. Maybe it's my thinking. I am thinking 'It's helicopter', where really it is a , what us in USA call a 'compound helicopter'. That is it is a fixed wing aircraft that uses rotary wings to help it fly. Sort of like a forgotten British Fairey RotoDyne. Except that Hind does not have puller prop, and Hind rotor is not always in state of autorotation like Rotodyne. But even with empty Hind and 20% fuel. I have to use almost all power and most of collective to hover below translation speed. With 40% fuel and weapons, I get into trouble below 30-20 kph. Maybe that is why I keep getting LTE in OGE and IGE hover, not enough power. My throttle GAS is INC MAX (to the right twist). Rolling T/O and rolling landings are fairly easy. Except, for me, with high crosswind, tipping Hind over. In Gazelle, you have to dash from tree line to tree line , and hide behind hills. I guess MI-24 is just to big and heavy for that kind of work. It needs to always be in translational lift.

Unlike in Gazelle and KA-50, if there is no smoke, I have hard time judging sideslip and wind direction. As from Hind pilot position, I cant really see the pitot boom vane. 

[DmitriKozlowsky]

Is there anything on real 24P that is digital? Sim is digital, but its simming analog hardware. Everything seems to be analog and manual. Map display for example. I thought it was a TV screen. But it looks like an acrylic microfiche display from library. LIke the navigation moving map displays from 1970's NATO Jaguar and A-7D/E. Where the map route was acrylic roll tape. Perhaps the engine governors?

Aircraft is like 1940's subway cars. Built to last a century. Impervious to EMP probably. No dainty circuits means no heavy Faraday cages for EMP shielding.

[MAXsenna]

1 minute ago, DmitriKozlowsky said:

Map display for example. I thought it was a TV screen. But it looks like an acrylic microfiche display from library. 

It's not even that, it's an actual map. On cardboard I believe. 

[admiki]

59 minutes ago, DmitriKozlowsky said:

Ya'know. Maybe it's my thinking. I am thinking 'It's helicopter', where really it is a , what us in USA call a 'compound helicopter'. That is it is a fixed wing aircraft that uses rotary wings to help it fly. Sort of like a forgotten British Fairey RotoDyne. Except that Hind does not have puller prop, and Hind rotor is not always in state of autorotation like Rotodyne. But even with empty Hind and 20% fuel. I have to use almost all power and most of collective to hover below translation speed. With 40% fuel and weapons, I get into trouble below 30-20 kph. Maybe that is why I keep getting LTE in OGE and IGE hover, not enough power. My throttle GAS is INC MAX (to the right twist). Rolling T/O and rolling landings are fairly easy. Except, for me, with high crosswind, tipping Hind over. In Gazelle, you have to dash from tree line to tree line , and hide behind hills. I guess MI-24 is just to big and heavy for that kind of work. It needs to always be in translational lift.

Unlike in Gazelle and KA-50, if there is no smoke, I have hard time judging sideslip and wind direction. As from Hind pilot position, I cant really see the pitot boom vane. 

Say what? I can load 100% fuel, 2x S8 pods and 8x ATGM and hover OGE no problem.

[DmitriKozlowsky]

I cant. Wont even break ground contact with 100% fuel and weapons. I need to be above 30 kph. maybe 50 to heavy take off. Forget hover. With throttles MAX'ed collective twist grip to MAX, collective at almost max, nose slightly up attitude, gear down. Aircraft sinks to ground . Do you place individual throttles to MAX > I keep them in default middle, and set collective grip twist throttle to MAX.

[MAXsenna]

43 minutes ago, DmitriKozlowsky said:

I cant. Wont even break ground contact with 100% fuel and weapons. I need to be above 30 kph. maybe 50 to heavy take off. Forget hover. With throttles MAX'ed collective twist grip to MAX, collective at almost max, nose slightly up attitude, gear down. Aircraft sinks to ground . Do you place individual throttles to MAX > I keep them in default middle, and set collective grip twist throttle to MAX.

Yeah, you're doing it wrong. The throttle is the twist on the collective. Watch it when you push the correctors to max.

I suggest you repeat the cold start training mission again. 

Cheers! 

[ARM505]

11 hours ago, admiki said:

SPUU 52 will limit right pedal travel to prevent damage to tailboom and TR itself, but that shouldn't be his problem with light helicopter

I meant to add this part, but didn't want to confuse the issue - I should have been more clear, that the yaw channel, when I last used it (I confess to not using it much at all) seems to progressively use up more and more of the available travel, unlike the SPUU which just limits a certain amount under certain conditions. And, the SPUU indication is clear on the control indicator (small arrow/chevron creeping in from the right on the pedal scale, unlike a potential problem with pedal travel where the position indicator just won't reach the maximum on the scale).

In response to something else somebody said, double tapping the trimmer to reset trim to nil no longer works (it worked in initial release, but was removed)

Edit to add more: Something is definitely still 'off' with the A/P yaw channel. If it is used, and ends up with an input during straight and level flight, and is then switched off, this input will be held in, essentially being a new 'neutral' position - I just did a flight, and ended up with some right pedal input, even though my physical pedals were centered. This then caused the inability to reach full pedal input to the left (the input mark stopped short of full deflection by the same amount the new center had been deflected by), and pedal input to the right to beyond the SPUU chevron limit.

Edited January 20, 2022 by ARM505
Trying to be more clear

[admiki]

TBH, I don't use it at all, only pitch/roll channels

[AeriaGloria]

4 hours ago, MAXsenna said:

Yeah, you're doing it wrong. The throttle is the twist on the collective. Watch it when you push the correctors to max.

I suggest you repeat the cold start training mission again. 

Cheers! 

Dmitri when referring to individual throttles might mean ECL levers, in Which case setting them to auto basically is max. If the ECLs are auto/middle, and collective gas throttle at max that should be fine. 
 

But yes perhaps a track or some video of startup. One thing I would do to troubleshoot startup other then tutorial missions is to watch auto steer up if the module has subtitles for each switch movement 

[DmitriKozlowsky]

5 hours ago, MAXsenna said:

Yeah, you're doing it wrong. The throttle is the twist on the collective. Watch it when you push the correctors to max.

I suggest you repeat the cold start training mission again. 

Cheers! 

Thats what I use, the twist grip. I leave the individual throttle levers in default mid position. I see rotor RPM at 92-93%, engine RPM at 95%.

[DmitriKozlowsky]

OK, the engine throttle levers have to in max UP position. Not just twist grip at INC MAX. That was not covered in Training StartUp. Thank you.

[DmitriKozlowsky]

9 hours ago, MAXsenna said:

It's not even that, it's an actual map. On cardboard I believe. 

Cant EMP good ole acetate paper map. True and magnetic north don't change. Well they do but very slooowwwllyyy. Although there were 'black' projects out in the desert , that tried to mess with local magnetic field in a way that a normal lensatic magnetic compass user would  not pick up unless he knew the offset of the day. As declinations would be different then what was on maps. Since ballistic missile gyros were tied to compasses, it was though that the interference would misguide so the missile would hit. Theoretically it may have worked, but quickly it was countered by cross checking astro-navigation using stars. So who knows what came of those programs. Could of messed with landnav of ground forces, until they would have gotten SATNAV GPS. Since GPS was used as early as early 1960's. It was likely judged as a waste of effort.  

So whats the trick of using 'paper' map display in our sims. If we are overflying known position on map,  slide the gridsquare cross over that. OK then what? Same as a marker on kneepad. Is there a waypoint caret that appears on HSI , as with DF? Or do we just do mental Magnetic To Grid Easterly ADD or MAGE acronym ,  Grid to Magnetic Easterly Subtract, then set that course? Or do we just cheat and use kneepad with marker to orient along our route? So analog!

[AeriaGloria]

2 hours ago, DmitriKozlowsky said:

OK, the engine throttle levers have to in max UP position. Not just twist grip at INC MAX. That was not covered in Training StartUp. Thank you.

This is not true, Middle/default is auto and they should work just fine that way. They basically do the same job as the twist grip just for an individual engine, you shouldn’t get any higher rpm out of both engines together by increasing them.

Ive heard sometimes in real life they would change the position of each ECL to correspond to the service life of each engine. I lightly used engine would have its individual level higher and the more used engine would have its levee lower, that way the gearbox would “expect” more power from the newer one, they are “condition”levers after all.

Why did increasing the ECLs actually help you? 

[DmitriKozlowsky]

4 minutes ago, AeriaGloria said:

This is not true, Middle/default is auto and they should work just fine that way. They basically do the same job as the twist grip just for an individual engine, you shouldn’t get any higher rpm out of both engines together by increasing them.

Ive heard sometimes in real life they would change the position of each ECL to correspond to the service life of each engine. I lightly used engine would have its individual level higher and the more used engine would have its levee lower, that way the gearbox would “expect” more power from the newer one, they are “condition”levers after all.

Why did increasing the ECLs actually help you? 

Don't know. Just does. In Training mission leaving ECL in default mid pos, works fine. But in custom missions, leaving ECL in mid and only MAX'ing on twist grip, I would not get enough power. In fact, I would get "Generator FAIL" Nagging'Nadya when accelerating and climbing, and HUD cross hairs would go off, AP channels would pop OFF, magnetic trim loss of power would have the biggest  effect on flight. Nose would snap to side up or down, depending on cyclic trim at time of generator loss. Then everything would power back up, only to once again loose power for short time. Putting ECL at max UP and twist grip throttle at max, makes all those problems go away. The rotor and engine RPM are all nicely bracketed by green lines. 93% as described in RTFM. 

[admiki]

3 hours ago, DmitriKozlowsky said:

Don't know. Just does. In Training mission leaving ECL in default mid pos, works fine. But in custom missions, leaving ECL in mid and only MAX'ing on twist grip, I would not get enough power. In fact, I would get "Generator FAIL" Nagging'Nadya when accelerating and climbing, and HUD cross hairs would go off, AP channels would pop OFF, magnetic trim loss of power would have the biggest  effect on flight. Nose would snap to side up or down, depending on cyclic trim at time of generator loss. Then everything would power back up, only to once again loose power for short time. Putting ECL at max UP and twist grip throttle at max, makes all those problems go away. The rotor and engine RPM are all nicely bracketed by green lines. 93% as described in RTFM. 

Look, this is going in circles. Just record a short track of your start and hover/takeoff. Even loosing generators should not lead to nose snapping anywhere. If I had to make ablind guess, you are not trimming at all and then loss of AP changes net input.

One thing people don't understand is that resultant inputs to rotor is a compound between actual flight controls and AP channels. Once AP shuts down, channels will go to neutral, changing result force to the rotor.

This is all moot, give us track.