Slip indicator broken in forward flight. Long standing issue. Proof Included.

[fapador]

I hope your long post shuts some mouths around here and finally gets this issue reported. Thank you for your time and effort you invested  towards it.

Now rest well my friend  @Tim_Fragmagnet

@NineLine @BIGNEWY time for action...

[Tim_Fragmagnet]

1 hour ago, fapador said:

I hope your long post shuts some mouths around here and finally gets this issue reported.

This issue had already obtained the "investigating" tag by staff, however I have recently changed the title of the thread to something more accurate, which has removed that tag from from the title, it is still there in the tags list however.

I just wanted thorough proof to be placed within the thread.
At this point the thread has
Photo / video evidence, and literal flight engineer data proof, I've also had plenty of word of mouth confirmation from flight engineers and actual huey crew members on my own time as well.

I declare it to be a complete report and that anyone saying it's wrong should read it all again.
There's a lot of confusion in this thread, I barely knew what was going on when I first looked into this myself, I was just someone noticing a pattern that wasn't being followed.
For anyone who still doesn't quite understand what's going on, don't worry, this is NOT a simple topic/concept, just know that the real UH-1H has specific patterns in its flight dynamics that the DCS module's instruments do not follow, in turn causing it to fly wonky if flown by the instruments.

Edited June 6, 2022 by Tim_Fragmagnet

[TrevorMcNeill]

Disclaimer: some explanations may not be perfect as I A)suck at explaining things and B) am still in flight school but I've talked extensively about these topics with my IP and academics instructors so they should be about 95% accurate.

So throughout reading this post I've found that alot of people seem to know just enough to sound smart to people who've never learned about helicopter flight. I say that because I see alot of either half accurate statements or just complete misunderstanding of certain effects.(shocking I know). I didn't read through everything as I saw a trend so some of what I'm about to say may have been stated before. 

 

To start let's talk about three very important topics when it comes to helicopter flight, that being Dissymmetry of lift, Translating Tendency, and Transverse flow. That will hopefully help going forward.

Before I get into those though, one other term is important to know and that is

gyroscopic precession: in short, the effect of a force placed upon the rotors will take place 90° later in the plane of rotation. This will make more sense as I go on

Dissymmetry of lift: 

In short, in counter clockwise rotating rotor disks, in forward flight, more lift on right side than left, gyroscopic precession causes that increased lift to take effect 90° later causing the nose to pitch up. Correction is forward cyclic.

Transverse flow:(not going into the specifics as it isn't important right now.)

The differential lift between the forward and aft halfs of the rotor disc,, in forward flight, causes increased lift in the forward half of the rotor disk, effect is 90° later causing roll right. Correction is left cyclic. Felt around 10-20kts

Translating Tendency, tendency for the helicopter to drift right due to a combination of main rotor torque and tail rotor thrust(again in counter clockwise spinning rotors) correction in a helicopter that has no factory implamented Correction(mast mounted tilted slightly left, cyclic rigged slightly left, or implemented through AP/SAS) is left cyclic.

So on to the trim ball, the correct action is to "step on the ball" ie ball is left, increase left pedal. Centering the trim ball doesn't correct for right drift, thats corrected by left cyclic.

Also I wanted to point out that when you have wind, your nose won't always align with direction of travel. IE if you're headed direct north and you have wind from the west, an aircraft in trim and maintaining a proper ground track of north will have its nose pointed off left the direction of travel. In helicopters with a navigation display like the one pictured below used in the lakota you can use the drift track indicator(the diamond) to help keep your ground track but in the huey you don't get that so it's up to you to maintain a north(in this case) ground track. 

Now hopefully I worded that in a good way as I tend to not explain things the best way possible and hopefully this clears some things up. Now I don't currently play DCS right now as im to busy with army flight school so I couldn't tell you if it works correctly but food for thought regardless.

 

 

Edited June 21, 2022 by TrevorMcNeill

[Tim_Fragmagnet]

@TrevorMcNeillwhile your post is quite detailed, it says a lot, without saying much that hasn't already been said over the course of the thread. It's just all condensed into one post.
It also makes the mistake of assuming all helicopters are the same, and that they act the same under different flight profiles.
Yes, your listed effects will generally be the same for every helicopter with a counter clockwise rotor.
Yes, while in the presence of wind, your ground track and nose heading will likely not be the same with the ball centered.
However, without the wind, that is not true for every helicopter. Different helicopters have different forces acting upon them in flight, some less balanced than others.

In the case of the huey, in forward (and apparently even rearward) flight, there are enough forces acting upon the aircraft that translating tendency is effectively completely cancelled out.
However, on something like an apache, translating tendency is nowhere near cancelled out by the forces generated by forward flight.

You want raw data proof?

Here is flight engineer data from a clean UH-1H flight showing the control positions at different sideslip angles in level flight with the shaded data points showing where the controls are when the ball is centered.

 

Now how about data for something like an apache?

 

Yes, the apache does fly with a right sideslip with the ball centered. It's about 6-6.5degrees.

 

The fun part is that the huey actually flies with 0.5degrees of LEFT sideslip.
And as a reminder, this thread wasn't originally about the sideslip, it was actually about the position of the pedals with the ball centered, which has already been proven to be wrong, while the overall flight model appears to be correct.

In short, the slip indicator is not taking the aerodynamic forces of forward and rearward flight into account.

Edited June 21, 2022 by Tim_Fragmagnet

[TrevorMcNeill]

@Tim_Fragmagnet so after reading it I don't think I did, yes, I'm saying all non tandem(ka-50) rotorblade helicopters have at least those three aerodynamic forces acting upon them(I won't speak to tandem as I don't know nor is it pertinent) but I never said that all have the same reaction to them. Most helicopters with tail rotors will require offset pedals in flight as you still need to counteract main rotor torque even though the vertical fin is helping to reduce that load on the tail rotor. 

 

As I had said I'm not the best at explaining and I was also trying to explain without going into too much detail as that's a whole book worth going into induced flow ect and so maybe the lack of detail put into the post is why it made it seem like it was grouping all helicopters into the same flight profile but it certainly wasn't the case I was trying to present.

 

As far as if it works as intended I'd literally have to fly it to see but if it's just a problem that the pedals are not at the same angle as the real thing then I don't see the issue. The trim ball is just that, to keep the aircraft aerodynamicly in trim. Again It's hard to see what the problem with it is without seeing a video but I just wanted to correct some of the things that had been said. You'd be suprised how much improper flight can effect trim but idk. Glad it had all been said before but as I said I had seen a Trend for quite a few posts including one saying that knowing the aerodynamic forces and understanding them wasn't important to a pilot which is far from the truth lmao.

Edited June 21, 2022 by TrevorMcNeill

[Tim_Fragmagnet]

@TrevorMcNeillthe details are all in the thread but I'll summarize here again

the DCS huey sees the slip indicator centered with the pedals to the left at cruise speeds, however real hueys of the same model fly with the pedals to the right with the ball centered.
Both visual evidence and actual flight engineer data corroborate this.
DCS is wrong on that front, by a fairly large margin, the real thing wants the pedals to the right with the ball centered at speeds as low as 25knots.

The next front is how it flies
In DCS with the ball centered, it flies with a fairly large amount of right sideslip, for many helicopters this is realistic, but once again, actual flight engineer data shows that the real thing flies with no sideslip with the ball centered, if not with a small amount of LEFT sideslip

If you move the DCS huey pedals to the realistic position, you fly mostly straight, in a realistic manner. It also relieves the pilot of a large amount of uncharacteristic wobbling and instability. But the ball is to the left. Meaning that in terms of this problem, the flight model itself is not at fault, it is the slip indicator incorrectly asking for the pedals to be to the left.

That is the entire issue, the slip indicator is broken and nothing else.
 

Edited June 21, 2022 by Tim_Fragmagnet

[Talisman_VR]

14 minutes ago, Tim_Fragmagnet said:

@TrevorMcNeillthe details are all in the thread but I'll summarize here again

the DCS huey sees the slip indicator centered with the pedals to the left at cruise speeds, however real hueys of the same model fly with the pedals to the right with the ball centered.
Both visual evidence and actual flight engineer data corroborate this.
DCS is wrong on that front, by a fairly large margin, the real thing wants the pedals to the right with the ball centered at speeds as low as 25knots.

The next front is how it flies
In DCS with the ball centered, it flies with a fairly large amount of right sideslip, for many helicopters this is realistic, but once again, actual flight engineer data shows that the real thing flies with no sideslip with the ball centered, if not with a small amount of LEFT sideslip

If you move the DCS huey pedals to the realistic position, you fly mostly straight, in a realistic manner. It also relieves the pilot of a large amount of uncharacteristic wobbling and instability. But the ball is to the left. Meaning that in terms of this problem, the flight model itself is not at fault, it is the slip indicator incorrectly asking for the pedals to be to the left.

That is the entire issue, the slip indicator is broken and nothing else.
 

 

Thanks for explaining this.  It has been confusing me for some time.

Happy landings,

Talisman

[TrevorMcNeill]

8 hours ago, Tim_Fragmagnet said:

@TrevorMcNeillthe details are all in the thread but I'll summarize here again

the DCS huey sees the slip indicator centered with the pedals to the left at cruise speeds, however real hueys of the same model fly with the pedals to the right with the ball centered.
Both visual evidence and actual flight engineer data corroborate this.
DCS is wrong on that front, by a fairly large margin, the real thing wants the pedals to the right with the ball centered at speeds as low as 25knots.

The next front is how it flies
In DCS with the ball centered, it flies with a fairly large amount of right sideslip, for many helicopters this is realistic, but once again, actual flight engineer data shows that the real thing flies with no sideslip with the ball centered, if not with a small amount of LEFT sideslip

If you move the DCS huey pedals to the realistic position, you fly mostly straight, in a realistic manner. It also relieves the pilot of a large amount of uncharacteristic wobbling and instability. But the ball is to the left. Meaning that in terms of this problem, the flight model itself is not at fault, it is the slip indicator incorrectly asking for the pedals to be to the left.

That is the entire issue, the slip indicator is broken and nothing else.
 

 

 OK I think that actually clears it up a bit. so what you're saying is that if you fly the Huey as it's intended realistically inside of DCS(right pedal) then it flies properly(in trim) but gives you incorrect trim indication.  Meaning that if you were to try to follow with the trim indicator is telling you and apply left pedal it would actually bring you out of trim to the left is that what you're saying?  If so yeah that's definitely incorrect and such a simple fixes well.

 

PS had a flight today to verify and uh-72 flies right pedal in when in trim as well

Edited June 21, 2022 by TrevorMcNeill

[fapador]

On 6/21/2022 at 7:09 PM, TrevorMcNeill said:

OK I think that actually clears it up a bit. so what you're saying is that if you fly the Huey as it's intended realistically inside of DCS(right pedal) then it flies properly(in trim) but gives you incorrect trim indication.  Meaning that if you were to try to follow with the trim indicator is telling you and apply left pedal it would actually bring you out of trim to the left is that what you're saying?  If so yeah that's definitely incorrect and such a simple fixes well.

 

PS had a flight today to verify and uh-72 flies right pedal in when in trim as well

Yes like Tim said. Even the Kiowa fly's with right pedal in level flight as I have confirmed with real pilot. In my country I see Huey's fly over my house all the time as Hellenic Army is still operating them, anyway's the left slip as @Tim_Fragmagnet said is actually so much I can actually notice it from the ground when looking at them flying at speed low altitude.

 

 

@BIGNEWY Still no update with what's going on with the remedy of this important issue...

Edited August 21, 2022 by fapador

[Dangerzone]

On 8/22/2022 at 6:38 AM, fapador said:

Still no update with what's going on with the remedy of this important issue...

I don't think there's much being done on the Huey anymore. The other issue (where the co-pilot takes over and steers straight) has been drifting to the right forever, and I don't think there's any intention to get this resolved either. I can't help but think that both of these could be related in some way but if the drift (which I thought would be as easy to fix as the slip indicator) isn't planned on being addressed - then this may follow the same.  Maybe there's only so much resources they're willing to throw at older modules? I don't know. (Which is sad, because as far as enjoyment of simple flight goes - the Huey is my absolute fav aircraft)!

[DishDoggie]

With total Respect to E.D. and all of us Huey Lovers

Price for the Model is at 49.99 By Belsimtek Never sorry to pay that for the Fun I have had.

To Quote a line from Dangerzone "I don't think there's much being done on the Huey anymore."

I wish I could say I don't feel the same way but I do and I am so sad by that. IS Belsimtek even in business any more? I honestly do not know. Is E.D. responsible for all needed updates and bug fix issues? Again I honestly do not know.

I do know a lot of us have reported a lot of issues with the Huey. I can honestly say when reported we had a genuine honest concern to report and take the issues to the People that take the issues in hand. Not faulting this process at all. It has been a Good part of the process. Thank you.

Sad but we have no movement in the area of patches to help us out yet with the Huey. So I do feel Dangerzone is right. I can say for myself "only" This issue and the very sad startup and shut down body rocking are 2 of my top of the list issues. like 1 and 2 on the list. Because I love this Model so much I have made Liveries and so I know of the sad long problems with the Shinny body and dull tail bug that a wonderful user named ams999 figured out was a 1 file fix to the ab-212.lods.Json file and it alone returns all Liveries to the intended way a livery was meant to look. Very easy fix that could be added into any patch at any time. The Only point I think I am dragging you into is If that is so easy and left to go not fixed. I am sad to say we may never see any patch fix for our beloved Huey. But I hope I'm wrong. 

[Dangerzone]

57 minutes ago, DishDoggie said:

The Only point I think I am dragging you into is If that is so easy and left to go not fixed.

It may seem as though it's so easy to fix, but often it's not. Well... to clarify - the fix is easy - but the debugging, debugging, monitoring, and then maintenance etc - what else could it alter that could cause problems can make a simple task end up eating more resources and time that was first anticipated.

I don't know where ED is at, but if they're anything like where I'm working at the moment - we have so many tasks to do and more being thrown at us - we are triaging tasks knowing that some requests may never ever get done because simply - there's too much to do, not enough staff to do it all - and what is deemed more important needs to take precedence over the others. 

I don't know if ED is in the same boat, and don't want to project my own experiences on to ED - but I do get a feeling that they have more work than they can poke a stick at, and they're also prioritizing - but the workload is so big that with the agile method they're using - some of the lesser tasks may never be seen to. While disappointing to consider - being on the other end of this as well - I can completely understand as well.

The big problem here I think is with Belsimtek not being around (or active?). Other dev's that are around developing models may have more time and take more pride in keeping patches done, etc. Like you - I hope I'm wrong and we see both of these resolved one day - but I'm also trying to be pragmatic and real about expectations. 

[Flappie]

@DishDoggie Back in June 2018:

Quote

Eagle Dynamics and Belsimtek

"We've been silent for a while and want to announce a new exciting change. Eagle Dynamics has been working hand in hand with Belsimtek for many years and together we have succeeded in creating some well-known products in the flight simulation community that we hope you enjoy. With the intent of further developing this success we have decided to align and strengthen our brand image under one banner, Eagle Dynamics. The team will remain unchanged and under the same leadership we are confident of delivering great new products to you. With the F-16C block 50, Mi-24P, AH-1S Huey Cobra and F-4E in the development pipeline, the future is very exciting. Together we look forward to taking Eagle Dynamics to the next level. Thank you."

https://forum.dcs.world/topic/248262-weekend-newsletters-2018/?do=findComment&comment=3517055

 

[DishDoggie]

@Flappie Thank You very much for educating me and finding the information to help me understand this, I know from your past involvement with other Items I put out about the Huey how helpful you are in our communities outreach to E.D. with our concerns and need for help with any Model and this one. Thank you for all you do. I hope to see official News statement of some fix and bug patches for our Huey community. Patience of waiting for things is what we do best. Thank You for all you are doing. 

[Xupicor]

I've noticed this too -- it's quite obvious even to a newbie pilot like me that if you try to center the ball in the Huey at speed something is completely off. For that reason, sadly, I ignore it completely and fly by what I see out the window and that gives me better results.

 

I'd also say the ball doesn't quite work right in the Apache, since if I try to follow it religiously I risk departing... Again, I tend to fly by what I see outside with regards to sideslip and ball centering, makes it much safer for me. That might be just bad newbie piloting on my part in the Apache, though.

It's saddening to see this issue still being seemingly ignored. I know ED uses SMEs when developing modules, but SMEs can make mistakes too, especially with so many different models of Hueys out there. That one post with different models pictured with tail rotors on different sides of the tail makes me think at least some SMEs flew different models than the one that's depicted by the sim and some facts just went under the radar.

I'm not even judging - things happen, it's not the end of the world. It would just be nice to have that fixed. Especially that the FM looks correct, and it's "just" the indicator that does something funky.

Edited September 12, 2022 by Xupicor

[sasquatch98]

On 4/2/2022 at 4:25 PM, WillyPete said:

It's also worth noting, that the trim problem affects other helicopters.  

Have a look at this following screenshots from Wag's video introducing flight in the Apache.  

The first shot shows the slip ball off to the left (same rotor system as huey) and the Flight Path Vector indiscator is centered.  
The second shows him in an "aerodynamically trimmed state" (his term) with the ball centered, but the FPV showing his heading off to the right.  
When in this state it is very obvious in the video, that he is crabbing right.  

 

It's not just the huey.

 

I just have to correct this since no one has yet the Apache and Huey do not have the same rotor system. The Huey has a semi rigid rotor which is why it’s susceptible to mast bumping and the Apache has an articulated rotor system.

[MoleUK]

On 9/12/2022 at 8:09 PM, Xupicor said:

I've noticed this too -- it's quite obvious even to a newbie pilot like me that if you try to center the ball in the Huey at speed something is completely off. For that reason, sadly, I ignore it completely and fly by what I see out the window and that gives me better results.

 

I'd also say the ball doesn't quite work right in the Apache, since if I try to follow it religiously I risk departing... Again, I tend to fly by what I see outside with regards to sideslip and ball centering, makes it much safer for me. That might be just bad newbie piloting on my part in the Apache, though.

It's saddening to see this issue still being seemingly ignored. I know ED uses SMEs when developing modules, but SMEs can make mistakes too, especially with so many different models of Hueys out there. That one post with different models pictured with tail rotors on different sides of the tail makes me think at least some SMEs flew different models than the one that's depicted by the sim and some facts just went under the radar.

I'm not even judging - things happen, it's not the end of the world. It would just be nice to have that fixed. Especially that the FM looks correct, and it's "just" the indicator that does something funky.

 

Yeah when I first started in the huey I went by the ball indicator, after a few weeks of that in VR I started getting serious back-ache problems lol. Now I know just to ignore it, which is unfortunate as it'd be nice to have an accurate indicator.