Bell UH-1H rotor mast orientation

Because I don't want to still pollute the other thread, I created a dedicated one here

It seems I'm the only one ( with Eagle Eye ) who affirm that the actual DCS Belsimtek UH-1 rotormast is pointing backward as it shouldn't... It is not like if I was saying that the skids are too high for a UH-1H helicopter ( and they are ) etc etc, as a model cannot be perfect and there are things that are more important than others ... and the rotormast not being straight vertical induce the whole rotor system to be canted backward, at neutral cyclic input, which is not accurate at all.

I will just copy my post from the other thread, so anyone of you will be able to build her/his opinion :

" Ok, will try to answer each posts

Are you a helicopter pilot in real life? If so, and you know how rotor disc suppose to be, then it's OK.

 

Or, these photos seem normal to me, as Rammit said, they are taxiing.

No, I am not yet, but will attempt army heli pilot selection soon, already PPL(A) and learning on helicopters for years, have already two logged hours on R44 and Bell 47. I obviously see that Mil is taxiing. You can spend time to find any pictures on the web etc, of the heli shut down, and you will notice the main mast has some forward degrees orientation, this is how helicopter are built in real world, that's all

*cough*

 

 

This is absolutely inaccurate, as the Huey rotorhead is a semi-rigid see/saw type, meaning there is a bearing in the hub that allow the whole hub/spindle shafts/blade grips assembly to freely rotate around that bearing, from around +10°/-10°!... this also explaining the possibility of mast bumping.

As you may see, all these Hueys are grounded, the rotor is put in almost it's rearmost position for the ground crew can " lock " the rotor ( tie the blade down ) to avoid them to flap with wind and such and so damage the mast ( like a " light " mast bumping ). Some operators also tie them in the forward position, it is just a matter of choice :

Ok so this has nothing to do, the rotor mast could be tilted 5° backward and you also could be able to place the rotor in that forward position.

Please, not again this stuff.

 

Yes, a main rotor mast is tilted forward on pretty much any helicopter.

Though when the helicopter is on the ground, rotor stopped or turning.

Things may look different.

 

Please just keep in mind that the rotor mast is tilted forward in relation to the helicopters waterline.

Which itself may well be titled backward when the helicopter is standing on the ground.

 

No way of knowing without consulting the manual.

 

And agree whit Alpha 1 6 here, controls are only at neutral whit rigging pins in.

And even then there can be exemptions.

 

Besides that, controls "neutral" could very well result in an control input, its just an reference from the manufacturer for when work is done on the flight control system.

And as such, is unique to every helicopter.

It isn't written in the manual, just because the main mast got an absolute Zero vertical orientation, perfectly perpendicular to the Helicopter 0° pitch attitude.

You still disagree ?

Okay, here is a picture I myself took in a 205 here in south France, flying for the Pompiers du Var ...

If you can't see that the rotor mast isn't 90° to the helicopter lines ( based on the skids ), well, then there is a problem. And no, it is not because the high skids configuration, they are exactly the same orientation as the low skid ones.

Now, look how things are in actual DCS model :

And even in the 3-view of their model, it not hidden at all that main mast is some degrees backward, and so cyclic at neutral produce a small back rotor disc tilting...

I have hard times understanding while all of you nice guys don't want to accept the real mast isn't straight ! I'm the first to say Belsimtek module is really a masterpiece of computer engineering, modeling, coding and texturing ! But saying all is perfect because you are so happy to be able to make a hover on their hard heli isn't a reason for saying it is perfect, this is UN-professional behavior and this sim ( DCS ) should considered as a professional tool now, not a Level D sim but much more than FSX games etc, the degree of realism in flight dynamics helped me alot when I got my hands on a real machine, as well as X-Plane advanced flight dynamics.

We paid 50 USD for the Beta, I think I am in the right to ask that to be FIXED for final, as well as you guys ask for the starter button and shutdown procedures to be done correctly, others ask for Radar alt, more weapon choice, Slick versions etc etc ...

Here, I'm criticizing a graphical thing, that shouldn't be hard to change for the final version, but I just don't understand why you still saying this is UN-true as I brought you all the proofs possible

OKAY , now I consider the matter closed regarding the Huey, if they don't want to correct that flaw, this is their problem but don't tell me please that what I'm saying is false. While I strongly hope they will fix that problem for final, as for a paid Beta, they should be listening a lot the customer feedback..

I just made the post to ask them not to do the same error in their upcoming M-8... no helicopters have their rotor discs canted backward just around neutral cyclic...

And now, this is how the Mi-8 rotor disc should look on ground, perfectly neutral ( rotor disc parallel to ground, not backward nor forward )

And in a slight forward cyclic input for taxiing

Thanks for having reading me,

Hueyman "

So, I ask you guys what do you think about that. Don't answer " no, this is nitpicking, the Huey sim is fabulous, it flies very well, you won't find anything better etc etc " as this is not the question

I ( and all of us here ) paid for a 50 USD Beta, it is absolutely NORMAL we ask for more improvements in the final version, and this one is obviously one of them to bring. It may not be important for you guys, who just discovered that helicopter more or less and that it is just another great heli module ... But for me and some guys here, the Huey is a true religion, and such big inaccuracy can't stay there for the final product.

I won't spend my time reporting every inaccuracies, like the rotorhead mechanism animation being totally fantasist ( the swashplate will never move the whole rotorhead assembly as it does now, not in a real Huey, nor any helicopter, only the light Gyrocopter does that ), seeing the push rods bending at their ball ends, instead of a correct mechanical rotation around the sphere like all rods, the max main blade angle pitch being way too coarse, blade chord being too large etc etc ( well, reporting now just for example, would not create a post for fixing the rotorhead animation for example ) BUT this one regarding the rotor mast should be fixed...

Once again, this is not a freeware product, and they accepted to let people spend money for an unfinished product, which is a great thing I think as long as they continue supporting it as much as they can until final ... instead of that, they started ( well, I think they started it much earlier we think ) and working hard on the Mi-8...

What do you think simmers/pilots ? Am I right or wrong ?

Part of the answer is there, and probably the best proof you can have :

After reading Hueyman`s complain and have a look by myself, at least I know what he is talking about. I absolutely don`t know if this have any relevance on flight dynamic calculations and what not, though I got his point.

 

I put this drawing from the Huey TM 55-1520-210-10 manual over the same drawing from the DCS Huey manual and shift it slightly forward. Look at the rotormast only. There are for sure differences in the types of Huey and I do not know if that matters, though I understand what Hueyman is talking about...and thats all I want to say for now.

 

And

Ignoring the fact this is the MI-8 thread:

 

Hueyman"s concerns are sound.

Did anyone have a look at the rotor disk yet during slow taxi ?

 

 

A little hint, the helicopter is not moving sideways

I set trim for 17-18 km/h forward flight and then left collective and cyclic alone, steering only with rudder around the airfield (no wind btw).

If some people still think I was decelerating in that screenshot, I will post the track too.

 

Now, who volunteers to explain to us that everything is fine with the disk in this screen and the total thrust vector is in fact pointing backwards ?!

 

Greetings

MadCat

But I have to add here, the total thrust vector is not pointing forward at all... while the rotor disc is a tiny bit ( but much less than it is now ! )

Why ? because if the little residual thrust of the T-53 exhaust...

Actually, that vector is obviously absolutely straight vertical in a perfect hover... while everything is compensating : lift, torque, side tail rotor thrust ( and induced roll moment, as the tail rotor is not on the roll axis but offset of the tail fin height ), turbine residual thrust etc etc ...

Please answer this:

What have the skid dimension/design to do with the mast orientation? and how can this relation be important ?

(regarding to your more than questionable comparison shots with the angle drawing - this "comparison" clearly using two different skids and your white line in the DCS shot isn't accurate.)

Just to give you another idea: Imagine the Mi8 is fully loaded and the main gears are almost flat... - where is the 'neutral' position now?

Further: How exactly do you define "Neutral" on a cyclic ?

Because the undercarriage are in aluminum tube construction, and is very flexible ( this ensuring the dampening ). It is easily understandable that higher skids have not the same mass repartition that lower, sturdier and more rigid ones. This could induce a slight change in the fuselage ( and so, rotor mast orientation, compared to the absolute horizontal ) pitch attitude on ground...

And on ground, high or low skids, the rotor mast is straight, not backward nor forward, but straight

Hope I replied to your question ;-)

I have a really basic question. Exactly what difference does it make to the 'big' picture, aside from aesthetics?

I have a really basic question. Exactly what difference does it make to the 'big' picture, aside from aesthetics?

It is a very interesting question, glad you asked it. You know, many things, got a kind of icon to make them very recognizable upon many other things... Huey got its sound, is rotor system , on ground, being tied down backward ( like most of Bell's teetering rotor system helis )

DCS is offers an accurate simulation experience, and this is part of the immersion. So, why people want to get rid of that derivated exhausts, like almost Huey all have ? because in their mind, the image they have of the Huey is the oen without that exhausts aiming rotor downwash, that's all.

Same for people who wants better avionics, realistic starter button, throttle cut-off/idle release simulation... because for them, it is a big part of the immersion... whereas the ship will still fly the same finally.

And for me, this is stuff relating to rotor mechanic, that's it, every one her/his " fetish " part, mine is the rotors/blade/propellers being done accurately.

Same for people who wants better avionics, realistic starter button, throttle cut-off/idle release simulation... because for them, it is a big part of the immersion... whereas the ship will still fly the same finally.

 

And for me, this is stuff relating to rotor mechanic, that's it, every one her/his " fetish " part, mine is the rotors/blade/propellers being done accurately.

Thanks for the answer.

My perspective on these types of issues is a bit different. Since manpower/resource/payroll are limited, I would prefer to see priority given to things that are more critical to game function and performance. Now if the 3D modeling guys have nothing else to do, then by all means fix it (assuminng it needs to be fixed), otherwise just put it in the queue, with an appropriate priority level, and take the next issue from the top of the stack.

It is not like if it was a new system to code or new part to model and texture.. it is existing things that needs a bit of relocation...

It seems their rotor model is really interactive with the physics, but at some point, there is obviously a relationship between the 3D model we see and what is actually calculated for flight dynamics... and this 3D " display " should be easy to edit isn't it ?

What can you see EB-1 ,is it out of your sight or is it feasible ?

Anyway, we are getting off topic, the question was, is it true or false that the mast isn't straight on this one, compared to the real one ...

I'd have to agree with Heuyman, it's obviously a bit out. BST are busy at work, hopefully this is not missed.

Just trying to fill this thread with some numbers:

(...having some numbers makes every discussion much easier)

Because the undercarriage are in aluminum tube construction, and is very flexible ( this ensuring the dampening ). It is easily understandable that higher skids have not the same mass repartition that lower, sturdier and more rigid ones. This could induce a slight change in the fuselage ( and so, rotor mast orientation, compared to the absolute horizontal ) pitch attitude on ground...

 

And on ground, high or low skids, the rotor mast is straight, not backward nor forward, but straight

 

Hope I replied to your question ;-)

No - you didn't answered my question(s).

 

No - you didn't answered my question(s).

 

Because you edited your post afterward.

That is correct with the Mi-8, not the Huey. And as you may know, each airframe got a load and CG sheet to fill in before everyflight. I don't know the CG min and max limits of the Mi-8, but it is somewhere around the rotor mast of course.

If you add weight on the CG, it will make the ship heavier ON it's CG, and so lowering down equally on front and aft of the ship ( I mean, no differences in pitch attitude )

Also, what I consider neutral is the mechanic neutral, not the " in flight one ". For example, if the PoH says the cyclic travel is 20° in each directions, the neutral is the 0° position.

Hope this answers this time.

And thanks for the picts, numbers are always good to see ;-)

I must add you choose a non orthographic pict ( mm.. this is obvious ), and shot so close to the Huey that the perspective effect makes it hard to takes measure from.

These are correct shots to measure from, and I see a perfect 90° straight angle. Aircraft manufacturer don't have to worry their factories with 0.3° differences in SUCH things ( yeah, some things like the blade pitch adjustment etc have much lower tolerances )

Seriously is it that important I think not that is just a ridiculous thing to be even looking at.

Don't forget the image you are comparing the real one to is by all accounts a game even if it is a simulation its still a game, did you actually morph yourself into the game with a spirit level and square rule to measure the dimensions no you dragged some lines across a screen capture how is that even anywhere near close to reality.

Don't forget that in DCS world the skids usually submerge themselves into the ground texture ever so slightly.

Also all those pictures of real Hueys would not have been parked on level ground either no runway in the world or hard stand is ever flat the ground always has a pitched angle to encourage water to run off to the drains so none of those Hueys would be sitting on level ground.

The point of this thread is determining if yes or no the mast is straight. If you don't want to investigate with us, then you can press the return button to choose another thread that may interest you.

I have much respect for all of you guys, really, but you complain for stuff like ( quoted for some new feature asking threads ) :

" Some instruments should oszillate. The Airspeed indicator oszillates approx. +/- 2Knots at 90 KIAS, the torque indicator increases oszillation with increasing torque, approx. +/-1 psi at 50 psi. "

" Add a rotor brake "

" Winch ability " etc etc ...

Before adding things, wouldn't the base empty model better be correct ?

So please stop giving your advices about if yes or not this correction is requested. It is DCS, it is not HAWX or ArmA, we pay for the excellence and it is normal we request it.

It is about as correct as it can be there is no need to start faffing around with the mast.

Like I said your real world comparisons can not be compared to this virtual world due to the limitations of the virtual world.

Never mind the fact that none of the Hueys in your pictures where you are drawing and dragging lines across are even sitting on level flat ground its just not comparable.

If you really want to be that anal about it send me an accurate schematic of the Huey and i'll open it up in my works auto cad sit it on a flat level line and then I will drag lines across it and tell you what the angles are exactly but that still wont help.

Hi all

Huyeman +1 :thumbup:

Have fun !!!:joystick:

I don´t understand, why some people try to deemphasize Hueyman´s point.

Hueyman, I´m absolutely with you. This is neither nonsense nor "as correct as it can be" to use your words Jay43.

PeterP you indeed showed with your mesurement of the angle of the main rotor mast, that BST made a mistake. And what is a beta for? Right, smashing bugs.

And this is an obvious bug. If the calculation of the aerodynamics is independent of the visual appearance, it should be no big deal to change it.

The main rotor mast of the real UH-1H is tilted forward by 5° to the helicopter´s longitudinal axis. So in Peter´s render picture, the blue angle should be 95°.

The 5° forward tilt is visible in real life and its absence is visible in the DCS Huey. That is why the DCS Huey´s main rotor is tilted backwards on the ground with the cyclic "mechanically" centered.

Maybe Hueyman was a little, well, lets say emotional about this. But he is absolutely right. He wants a mistake being corrected in the DCS Huey, and i think this is something we all want. So the DCS Huey can become "as correct as it can be" on a PC.

Jay43, you don´t need autocad or something like that. Just have a look at the TM 55-1520-210-10 Chapter 6, page 5 figure 6-1. The lower picture.

FoxRomeo

Nate

:doh::doh::doh: THANKS GUYS :doh::doh::doh:

I really understand the fact that some improvements are in trop priority before others ( like this one is not top priority ), though they HAVE TO work hard to deliver the best product they can, or I don't think anyone will pay anymore for their next product's Beta ...

And I wasn't totally right too, I knew inside of me that it has some degrees forward, but as I didn't found any solid material to prove it, and in order not to shock other pessimist guys too much ( ... lol ), I just said it was straight...

Now, Belsimtek, please make this +5° forward mod for final ...

Thanks, the matter is closed... hopefully solved soon :pilotfly:

So please stop giving your advices about if yes or not this correction is requested. It is DCS, it is not HAWX or ArmA, we pay for the excellence and it is normal we request it.

Hueyman, I have no technical knowledge in this area so I shant/cant comment, but perhaps looking at an engineering manual or contacting some Huey pilots might provide you with a definitive answer?

While I agree that ED DCS sets the bar high in terms of standard and that where ever possible a precedent should not be allowed to be set that needlessly compromises sim fidelity I think ultimately you need to speak with Belsimtek offline and persuade them. Really the people on this forum will spout off a load of rubbish and even some genuine accurate points. One way or the other though you need to change the mind only of Belsimtek and this may best be done subtly offline away from public scrutiny.

If you can't persuade them or ED then it really doesn't matter one way or the other and I fear you may be tilting at windmils.

Good luck though mate (assuming your right),

-Sharpe

Yeah Sharpe I agree with you, I contact them now.

And I think the real " engineering " proof is the just above " Helicopter Station Diagram "

Yeah Sharpe I agree with you, I contact them now.

 

And I think the real " engineering " proof is the just above " Helicopter Station Diagram "

No need, I've added it into the Buglist. This does NOT mean it will be fixed. If I hear anything back I'll let you know.

Nate

No need, I've added it into the Buglist. This does NOT mean it will be fixed. If I hear anything back I'll let you know.

 

Nate

Thanks Nate " In Real Life " ? :smartass:

 

Nate

Floor level attitude. This may prove to hurt your case Hueyman. I can't explain right now. I will tonight when I can get off my phone.

Floor level attitude. This may prove to hurt your case Hueyman. I can't explain right now. I will tonight when I can get off my phone.

See Below

Nate

Check the ground level Nate,

The deck (floor) of a uh1 sits at 5.45 degrees while on the ground empty. I personally took this measurement from a calibrated source. This puts the rotor in your 1st picture at .45 degrees after on the skis.

When in alpha I spent a few days taking all the early complaints on model errors and checked them with a calibrated source on a UH-1H. I found all of them within .5 degree. I did not report any of the complaints based on that data.

Check the ground level Nate,

 

The deck (floor) of a uh1 sits at 5.45 degrees while on the ground empty. I personally took this measurement from a calibrated source. This puts the rotor in your 1st picture at .45 degrees after on the skis.

 

When in alpha I spent a few days taking all the early complaints on model errors and checked them with a calibrated source on a UH-1H. I found all of them within .5 degree. I did not report any of the complaints based on that data.

Perhaps I'm Misunderstanding you, the ground angle in my opinion should not be considered at all. It is irrelevant.

The Diagram shows the Rotor mast at a 5 deg angle from Huey Deck perpendicular. The DCS model does not have this 5 deg offset from the Deck perpendicular.

Nate