Need advice - Landing = Descending + Deceleration? For me ... it equals VRS :(

[Garuda]

Sorry if this was already stated:

The rudders also need to watched. When you slow below 20 knots and start to move through transition the helicopter starts to shake and yaw to the right, naturally you apply left pedal too stop the right yaw; This increases power to the tail rotor but decreases power to the main rotors. So during transition you are loosing lift from the main rotors and the application of the left pedal also causes another loss in lift... double trouble.

 

Again, sorry if this has been sorted and I am repeating something.

 

Adding power to maintain tail rotor RPM also maintains main rotor RPM, there is no decrease. As long as the engine is capable of producing more power there is no loss in lift

[outlawal2]

Adding power to maintain tail rotor RPM also maintains main rotor RPM, there is no decrease. As long as the engine is capable of producing more power there is no loss in lift

 

He is not referring to more engine power, he is referring to tail rotor power..

 

When you push the anti torque pedals (There is no rudder on a helicopter) you put drag on the tail rotor and this causes tail rotor thrust making the helicopter turn in the direction you have told it to go with the pedals.. This torque on the tail rotor takes power AWAY from the main rotor so you will sink slightly requiring you to pull some collective to compensate for it...

 

If you turn LEFT, the helicopter will sink slightly.. If you turn RIGHT, it will ASCEND slightly... Quite a juggle when learning in RL in the wind!...

 

UNLESS of course you are flying a Eurocopter... Since the main rotor turns the opposite direction of a Huey, Turning LEFT makes it ASCEND and turning RIGHT makes it DESCEND... Also makes takeoff interesting as it wants to turn LEFT during takeoff so you have to put RIGHT pedal in to straighten it out..

Edited June 19, 2013 by outlawal2
More to add

[Garuda]

He is not referring to more engine power, he is referring to tail rotor power..

 

When you push the anti torque pedals (There is no rudder on a helicopter) you put drag on the tail rotor and this causes tail rotor thrust making the helicopter turn in the direction you have told it to go with the pedals.. This torque on the tail rotor takes power AWAY from the main rotor so you will sink slightly requiring you to pull some collective to compensate for it...

 

If you turn LEFT, the helicopter will sink slightly.. If you turn RIGHT, it will ASCEND slightly... Quite a juggle when learning in RL in the wind!...

 

UNLESS of course you are flying a Eurocopter... Since the main rotor turns the opposite direction of a Huey, Turning LEFT makes it ASCEND and turning RIGHT makes it DESCEND... Also makes takeoff interesting as it wants to turn LEFT during takeoff so you have to put RIGHT pedal in to straighten it out..

 

There is no tail rotor power vs main rotor power. You would only lose lift if main rotor rpm is decayed, which would only happen if you made large abrupt inputs to the left pedal. In that case you may decrease both main rotor (and tail rotor) rpm before the engine can add more power to compensate for the increase in drag.

[outlawal2]

There is no tail rotor power vs main rotor power. You would only lose lift if main rotor rpm is decayed, which would only happen if you made large abrupt inputs to the left pedal. In that case you may decrease both main rotor (and tail rotor) rpm before the engine can add more power to compensate for the increase in drag.

 

Garuda I can assure you that what I am saying is correct and I have experience with it in real life... BOTH the tail rotor and the main rotor are connected and receive power from the same gearbox. This means that any addition or reduction in TORQUE affects both of them at the same time. So if the TAIL ROTOR puts torque into the system (Like when you push the pedal ) it does affect the main rotor at the same time.. just the way I stated it earlier. In very large helicopters with tons of horsepower the affect is not as noticeable, but I promise you that in a Robinson R22 it is a BIG difference as you have precious little power to spare...

 

If you still don't believe what I am saying then find the book "Principles of Helicopter Flight" By Wagtendonk... Read that book (as I have) and you will fully understand what I am saying..

 

Follow what I am saying and anticipate what the helicopter is going to do and WHY, and you will become a much better pilot and what the machine is doing will make a lot more sense to you..

[Rogue Trooper]

There is a slight drop off in lift which you don't need when transitioning. when I Initially flew the Huey I reacted to the right bank in alarm when transitioning and immediately applied compensation with the left pedal plus course correction to stop the yaw (read fast large left rudder movement) then I noticed the overwhelming vertical velocity problem!

[outlawal2]

There is a slight drop off in lift which you don't need when transitioning. when I Initially flew the Huey I reacted to the right bank in alarm when transitioning and immediately applied compensation with the left pedal plus course correction to stop the yaw (read fast large left rudder movement) then I noticed the overwhelming vertical velocity problem!

 

That is why very SMOOTH movements are a must in a helicopter especially during landing.. The automatic throttle on most helicopters will compensate for the added torque but it is not instantaneous and a drop in altitude will occur when you put pedal in.. The key is anticipating this and putting in some left pedal smoothly while pulling collective (Also smoothly) to compensate for these tendencies... It takes a LOT of practice to get it right and every helicopter will be slightly different...

[Rogue Trooper]

That is why very SMOOTH movements are a must in a helicopter especially during landing.. The automatic throttle on most helicopters will compensate for the added torque but it is not instantaneous and a drop in altitude will occur when you put pedal in.. The key is anticipating this and putting in some left pedal smoothly while pulling collective (Also smoothly) to compensate for these tendencies... It takes a LOT of practice to get it right and every helicopter will be slightly different...

 

Yeah I agree .

Smoothness is the key. Anticipate what you know the helicopter will do!

[Garuda]

Garuda I can assure you that what I am saying is correct and I have experience with it in real life... BOTH the tail rotor and the main rotor are connected and receive power from the same gearbox. This means that any addition or reduction in TORQUE affects both of them at the same time. So if the TAIL ROTOR puts torque into the system (Like when you push the pedal ) it does affect the main rotor at the same time.. just the way I stated it earlier. In very large helicopters with tons of horsepower the affect is not as noticeable, but I promise you that in a Robinson R22 it is a BIG difference as you have precious little power to spare...

 

If you still don't believe what I am saying then find the book "Principles of Helicopter Flight" By Wagtendonk... Read that book (as I have) and you will fully understand what I am saying..

 

Follow what I am saying and anticipate what the helicopter is going to do and WHY, and you will become a much better pilot and what the machine is doing will make a lot more sense to you..

 

As you pull up on the collective drag on the main rotor increases, which will decrease main rotor RPM and tail rotor RPM if engine power is not increased. The governor automatically does this, so rotor RPM is maintained. Same thing applies to the tail rotor. As you apply left pedal drag increases on the tail rotor, which would decrease both tail rotor RPM and main rotor RPM if no additional power is applied. Again, the governor automatically increase engine power so rotor RPM is maintained. If rotor RPM is maintained, there is no loss in lift.

 

Only if large abrupt inputs are made (increasing drag too quickly for the engine to supply more power), or there is no governor automatically increasing engine power would you lose rotor RPM while applying left pedal.

 

Also, I know you have experience in the R22 from the other VRS thread. While I appreciate that you have helicopter flying experience, do not think that other people on this forum do not.

[outlawal2]

All I can tell you is that an R22 definitely acts exactly the way I have described and all helicopters will do this to some extent. The less overall power you have at your disposal the more this effect will rear it's ugly head.. As I stated before, the automatic governor is NOT INSTANTANEOUS and the helicopter will rise or fall when you push the pedals. The DCS Huey SIM also shows this behavior when landing...

 

And for the record it kinda freaked me out in the real helicopter at first because when trying to hover the damned thing porpoised up and down quite a bit as I worked the pedals.. Damned disconcerting when you don't expect it.

 

It is what it is...

 

Come on folks, where are the helicopter flight instructors out there? What I am saying is the facts so let's get an instructor to chime in... I know there are a few on the forum..

 

AND if you still refuse to believe what I say then maybe you might believe the information provided right in the Huey PDF manual on page 103...

 

"b) When initiating a LEFT hovering turn, the pilot first adds left pedal, which increases tail rotor thrust and produces a slight bank to the right (1 – 3°) and slip to the right. Slight LEFT cyclic (1/8 – 1/10 of its movement range) is required to compensate for these tendencies and maintain the turning center point near the main rotor vertical axis. In addition, the transfer of power to the tail rotor produces a reduction in main rotor RPM (by 3 – 5 RPM) in the initial moments after input of the left pedal (when left pedal input is significant), leading to a slight loss of altitude (0.5 – 1.5 ft). It may take the engine governor up to 2 – 4 seconds to compensate and return the main rotor RPM to its starting value, at which point the helicopter may experience a slight climb rate (depending on the rate of yaw and available engine power). The climbing tendency occurs due to the increased velocity of the main rotor blades when combined with the helicopter's own rate of yaw relative to the surrounding air. The extent of all of the dynamic tendencies described depends on the aggressiveness of pedal input and the established rate of yaw.

Edited June 19, 2013 by outlawal2
Data from the manual

[Weta43]

Again, the governor automatically increase engine power so rotor RPM is maintained. If rotor RPM is maintained, there is no loss in lift.

 

If the Huey's governor's action was instantaneous, and there were no change in rotor rpm, this would be true, but it's not, so there is, so it's not ...

[Garuda]

All I can tell you is that an R22 definitely acts exactly the way I have described and all helicopters will do this to some extent. The less overall power you have at your disposal the more this effect will rear it's ugly head.. As I stated before, the automatic governor is NOT INSTANTANEOUS and the helicopter will rise or fall when you push the pedals. The DCS Huey SIM also shows this behavior when landing...

 

And for the record it kinda freaked me out in the real helicopter at first because when trying to hover the damned thing porpoised up and down quite a bit as I worked the pedals.. Damned disconcerting when you don't expect it.

 

It is what it is...

 

Come on folks, where are the helicopter flight instructors out there? What I am saying is the facts so let's get an instructor to chime in... I know there are a few on the forum..

 

AND if you still refuse to believe what I say then maybe you might believe the information provided right in the Huey PDF manual on page 103...

 

"b) When initiating a LEFT hovering turn, the pilot first adds left pedal, which increases tail rotor thrust and produces a slight bank to the right (1 – 3°) and slip to the right. Slight LEFT cyclic (1/8 – 1/10 of its movement range) is required to compensate for these tendencies and maintain the turning center point near the main rotor vertical axis. In addition, the transfer of power to the tail rotor produces a reduction in main rotor RPM (by 3 – 5 RPM) in the initial moments after input of the left pedal (when left pedal input is significant), leading to a slight loss of altitude (0.5 – 1.5 ft). It may take the engine governor up to 2 – 4 seconds to compensate and return the main rotor RPM to its starting value, at which point the helicopter may experience a slight climb rate (depending on the rate of yaw and available engine power). The climbing tendency occurs due to the increased velocity of the main rotor blades when combined with the helicopter's own rate of yaw relative to the surrounding air. The extent of all of the dynamic tendencies described depends on the aggressiveness of pedal input and the established rate of yaw.

 

If you want any flight instructor's opinion, I can tell you mine again. I do both right and left pedal turns in R44s and R22s every day I'm at work. I completely disagree with your statement that left pedal turns in either of these aircraft cause a loss in lift, since the piston engine combined with low inertia blades means the governor can keep rotor rpm right at the top of the green arc when turning without issue. The most important thing to stress is the use of lateral cyclic due to an increase or decrease in translating tendency in order to maintain position over the ground (as well as keeping the cyclic pointing into the wind on windy days).

 

I will say again that I have zero experience in Hueys, and that I've never flown any turbine helicopter. Yes, turbine engines are not capable of increasing power as rapidly as a piston by a decent amount of time.

 

I will say that I just jumped into DCS Huey not 5 minutes before posting this and checked to see if left pedal turns caused any noticeable decay in rotor RPM. The only time the RPM needle even moved was going from full right pedal to immediate abrupt full left pedal, and even then it barely moved at all. Also to note, zero loss in lift, even after doing this repeatedly as aggressively as I could for a few minutes, at no point ever moving the collective from its original hover position.

 

So either the sim needs an update, or there is no noticeable effect to lift while making left pedal turns. I am not an expert on anything about helicopters, but I do get paid to fly them a lot.

[Weta43]

Ok, I just tried it isn SIM (just to make sure this hadn't disappeared from the FM).

In a hover ~ 4' or 5' off the ground, hard left pedal causes a small drop for the first 3/4 of a turn (observable from outside, and in a small movement of the VVI), then the governor catches up and the aircraft goes back to it's original hight, right ruddder has the opposite effect.

[Garuda]

Ok, I just tried it isn SIM (just to make sure this hadn't disappeared from the FM).

In a hover ~ 4' or 5' off the ground, hard left pedal causes a small drop for the first 3/4 of a turn (observable from outside, and in a small movement of the VVI), then the governor catches up and the aircraft goes back to it's original hight, right ruddder has the opposite effect.

 

Okay, well I don't know why mine is different. I just tried it again and made sure to save the track. I do not move the collective at all once in a hover, and I do not see any loss in lift with full left pedal input. I even start by applying full right pedal for a few seconds before putting in hard left pedal and the helicopter does not settle even one inch. I have the current updated version.

Pedal_Turns.trk

[HuggyBear]

I'm posting a cut and paste of a similar discussion in the Tester Forum.

 

-----

 

Increasing left pedal increases tail rotor pitch which slows the N2/NR and causes a momentary descent. The governor senses this NR droop and increases N1/TQ to recover N2/NR and the descent will stop.

 

However:

 

If the left pedal turn is continued the aircraft will begin to climb...

 

NR is sensed by the NR tachometer attached to the airframe so any NR indications in the cockpit or input to the governors are relative to the airframe. the lift produced by the rotor system varies with NR relative to the air.

 

(I know, there are about a million other tiny variables, but for the purpose of this discussion that'll do nicely)

 

With any left pedal turn (the same direction as the rotor) the NR relative to the airframe will droop. The NR tacho will sense this droop relative to the airframe and increase N1/TQ to recover N2/NR relative to the airframe.

 

This results in an NR relative to the air which is slightly higher than normal, creating more lift, resulting in a climb.

 

The reverse is true for the right pedal turn (the opposite direction to the rotor).

 

With the pedal turn to the right the NR relative to the airframe will increase. the NR Tacho will sense this increase and decrease N1/TQ to recover NR relative to the airframe.

 

This results in an NR relative to the air which is slightly lower than normal, creating less lift, resulting in a descent.

 

-----

 

I tested pedal turns in the B412 which is similar to the UH-1H, although upgraded engines, governors, FCU and rotors, although still old mechanical equipment, with no FADEC or other digital control of the engines.

 

Turns were made at approx 40 degrees per second through 360 degrees.

 

Left Pedal turn:

 

The aircraft descended approximately 1 foot over the first 60 degrees, then climbed 15-20 feet over the remaining 300 degrees of the turn.

 

Right Pedal turn: The aircraft remained stable over the first 45 degrees, then descended 20-25 feet over the remaining 315 degrees of the turn.

 

The rate of descent during the right turn was slightly higher than the rate of climb during the left turn.

 

-----

 

In practice none of this matters a lot, just use your hands and feet to keep your arse where you want it and don't worry so much about why things are happening, just try to learn when they happen. :).

 

- Bear

[dahui]

I'm posting a cut and paste of a similar discussion in the Tester Forum.

 

-----

 

Increasing left pedal increases tail rotor pitch which slows the N2/NR and causes a momentary descent. The governor senses this NR droop and increases N1/TQ to recover N2/NR and the descent will stop.

 

However:

 

If the left pedal turn is continued the aircraft will begin to climb...

 

NR is sensed by the NR tachometer attached to the airframe so any NR indications in the cockpit or input to the governors are relative to the airframe. the lift produced by the rotor system varies with NR relative to the air.

 

(I know, there are about a million other tiny variables, but for the purpose of this discussion that'll do nicely)

 

With any left pedal turn (the same direction as the rotor) the NR relative to the airframe will droop. The NR tacho will sense this droop relative to the airframe and increase N1/TQ to recover N2/NR relative to the airframe.

 

This results in an NR relative to the air which is slightly higher than normal, creating more lift, resulting in a climb.

 

The reverse is true for the right pedal turn (the opposite direction to the rotor).

 

With the pedal turn to the right the NR relative to the airframe will increase. the NR Tacho will sense this increase and decrease N1/TQ to recover NR relative to the airframe.

 

This results in an NR relative to the air which is slightly lower than normal, creating less lift, resulting in a descent.

 

-----

 

I tested pedal turns in the B412 which is similar to the UH-1H, although upgraded engines, governors, FCU and rotors, although still old mechanical equipment, with no FADEC or other digital control of the engines.

 

Turns were made at approx 40 degrees per second through 360 degrees.

 

Left Pedal turn:

 

The aircraft descended approximately 1 foot over the first 60 degrees, then climbed 15-20 feet over the remaining 300 degrees of the turn.

 

Right Pedal turn: The aircraft remained stable over the first 45 degrees, then descended 20-25 feet over the remaining 315 degrees of the turn.

 

The rate of descent during the right turn was slightly higher than the rate of climb during the left turn.

 

-----

 

In practice none of this matters a lot, just use your hands and feet to keep your arse where you want it and don't worry so much about why things are happening, just try to learn when they happen. :).

 

- Bear

 

 

This is how you Fly sometimes in Logging OPS with the Lama, where you dont have a Torque Indicator or Limitation. You have the Blade Angle like in the KA50 and a small "Computer/Calculator" where you get the information with the OAT and Altitute, how much Collective you can Pull. When you are in Maximum then, you can Push the PowerPedal and the Climb will begin :)

[lxvanwyk]

Although the fm for Huey is very realistic I still believe the VRS modeling is a bit over the top as well as the gyro effect when increasing and decreasing collective pitch. I myself have been caught in the initial stages of vrs and it was frightening however this only occurred after hovering for approx 22 min in one place (on hover ball) and with a change of wind direction from on the nose to a quick tail gust. This model for Huey is a bit rough in my opinion however it does pose a challenge and really keeps you on your toes.

[outlawal2]

If you want any flight instructor's opinion, I can tell you mine again. I do both right and left pedal turns in R44s and R22s every day I'm at work. I completely disagree with your statement that left pedal turns in either of these aircraft cause a loss in lift, since the piston engine combined with low inertia blades means the governor can keep rotor rpm right at the top of the green arc when turning without issue. The most important thing to stress is the use of lateral cyclic due to an increase or decrease in translating tendency in order to maintain position over the ground (as well as keeping the cyclic pointing into the wind on windy days).

 

I will say again that I have zero experience in Hueys, and that I've never flown any turbine helicopter. Yes, turbine engines are not capable of increasing power as rapidly as a piston by a decent amount of time.

 

I will say that I just jumped into DCS Huey not 5 minutes before posting this and checked to see if left pedal turns caused any noticeable decay in rotor RPM. The only time the RPM needle even moved was going from full right pedal to immediate abrupt full left pedal, and even then it barely moved at all. Also to note, zero loss in lift, even after doing this repeatedly as aggressively as I could for a few minutes, at no point ever moving the collective from its original hover position.

 

So either the sim needs an update, or there is no noticeable effect to lift while making left pedal turns. I am not an expert on anything about helicopters, but I do get paid to fly them a lot.

 

OK so you are a flight instructor and fly them everyday? Then I am really intrigued now as I have experienced this phenomena in the R22 personally so now I am wondering why our experiences differ? I don't believe either one of us to be liars so SOMETHING must be affecting this... Air density / temperature, I don't know, but I have felt this many times when hovering... And if you say you are an instructor and say you have NOT felt this, I believe you but still wonder why the difference?

 

Regardless, it is real and my experience, the book I recommended as well as the documentation provided with the Huey module all support it...

[Zlin]

I was having a lot of vrs issues as well. I saw a post somewhere up here that the auto updater was not working properly and to manually download the latest version of the Huey module, which ends in ...186 then uninstall the Huey module and reinstall from the ..186 version. I did this and noticed a dramatic difference in the fm and am not having vrs issues any longer unless I really rush my landings.

 

Not sure is this will help but it made a big difference for me.

[Flagrum]

I was having a lot of vrs issues as well. I saw a post somewhere up here that the auto updater was not working properly and to manually download the latest version of the Huey module, which ends in ...186 then uninstall the Huey module and reinstall from the ..186 version. I did this and noticed a dramatic difference in the fm and am not having vrs issues any longer unless I really rush my landings.

 

Not sure is this will help but it made a big difference for me.

I'd say, it's the "placebo effect".

 

Lol, I had high hopes on this one as well. But ... I ran the autoupdater, too. Some log-file stated I had version xxx.168. Then I did a file comparison (by using the JSGME Tool): no changes. Then I installed the stand alone version of the Huey (that with version xxx.186) and compared the changes again: no difference. (i'd say, it is only a typo in the installer file ... .168 ...186)

[outlawal2]

I'd say, it's the "placebo effect".

 

Lol, I had high hopes on this one as well. But ... I ran the autoupdater, too. Some log-file stated I had version xxx.168. Then I did a file comparison (by using the JSGME Tool): no changes. Then I installed the stand alone version of the Huey (that with version xxx.186) and compared the changes again: no difference. (i'd say, it is only a typo in the installer file ... .168 ...186)

 

No sir, it is NOT a typo and is not a "placebo" affect. Please do not talk about things unless you actually know what you are talking about. I am the one that posted that fix and it DEFINITELY is a fix for some folks. And the version numbers are not there to be pretty.. I HAD .168 and had multiple issues with it. I then loaded .186 and it made a DRAMATIC difference..

 

Don't muddy things up unless you have real, credible information to share with folks because stating what you did only hinders other people's ability to fix a real issue they may be having..

[YorZor]

OK so you are a flight instructor and fly them everyday? Then I am really intrigued now as I have experienced this phenomena in the R22 personally so now I am wondering why our experiences differ? I don't believe either one of us to be liars so SOMETHING must be affecting this... Air density / temperature, I don't know, but I have felt this many times when hovering... And if you say you are an instructor and say you have NOT felt this, I believe you but still wonder why the difference?

 

Regardless, it is real and my experience, the book I recommended as well as the documentation provided with the Huey module all support it...

 

 

Small piston helicopters suffer from it certainly. In the H-269c it was there for sure. And just asked a friend who flies the r22 and he has the opinion. It is there however subtle. It's is very minute and most of the time you notice it the most in hover when you're doing spot-turns with high winds.

[doveman]

No sir, it is NOT a typo and is not a "placebo" affect. Please do not talk about things unless you actually know what you are talking about. I am the one that posted that fix and it DEFINITELY is a fix for some folks. And the version numbers are not there to be pretty.. I HAD .168 and had multiple issues with it. I then loaded .186 and it made a DRAMATIC difference..

 

Don't muddy things up unless you have real, credible information to share with folks because stating what you did only hinders other people's ability to fix a real issue they may be having..

 

He did share "real, credible information". He compared the files from .168 and .186 and apparently there was no difference whatsoever.

[outlawal2]

He did share "real, credible information". He compared the files from .168 and .186 and apparently there was no difference whatsoever.

 

 

So.. I just made it up as a gag?

 

CORRECTION: There was no difference whatsoever for HIS system...

 

This is no way makes it true for everyone...

 

Why is this such a tough concept for people?

 

If he wants to say "Nope, it didn't work for me" , then more power to him and I say, sorry it didn't work for you.

 

But revision numbers in software denote differences in programming and they are not changed and released for the fun of it.

 

I posted the fix because it made a huge difference on MY system.. the poster above also said it made a difference on HIS system so it is not just my system that had the issue so it is safe to assume that others may have the same problem..

[Flagrum]

No sir, it is NOT a typo and is not a "placebo" affect. Please do not talk about things unless you actually know what you are talking about. I am the one that posted that fix and it DEFINITELY is a fix for some folks. And the version numbers are not there to be pretty.. I HAD .168 and had multiple issues with it. I then loaded .186 and it made a DRAMATIC difference..

 

Don't muddy things up unless you have real, credible information to share with folks because stating what you did only hinders other people's ability to fix a real issue they may be having..

 

Erm ... wtf?

 

Well, then tell me please how I check what exact version of the Huey module I have installed.

[outlawal2]

Erm ... wtf?

 

Well, then tell me please how I check what exact version of the Huey module I have installed.

 

In the other thread I talked about that... There is no way (That I know of) to verify the exact version once it is installed.. (In my case I still had my original module install file saved away and it ended in .168... I then went out to the web and looked at the version currently out there and it ends in .186 and that is what prompted me to try the re-install)

 

If you want to try it, you will need to uninstall your existing Huey module, RESTART your machine and then install the .186 module off the website... I don't recommend trying to just install over top as that seldom works and could cause worse issues...

 

In my case it made a world of difference in regards to VRS.. With the old version I was augering into the ground repeatedly.. With the new version I have not had VRS issues at all and this is much more realistic according to what I have read and what real Huey pilots have said...