Cyclic - can't maintain attitude?

[FragBum]

Oh right fig 15-4 pp126 :) describing the same thing.

 

second edition.

 

:thumbup:

[Holton181]

Right, but in the same way wrong. Thats because the G-force and formula I referred to is actually

 

the calculation to maintain the same lift vertical to the earth. Your description is another way to describe the same as G= 1/(cos bank angle). So it is not ’in addition’ :)

 

I see your point. My confusion was due to a matter of what terminology used, and I believe we use different ones. You using G-force (=acceleration) and I'm using centripetal force (times mass=acceleration) and gravity (=acceleration).

But I generally only consider force x mass = acceleration (circular and linear) as G-force, and not gravity, which is of course wrong (especially since gravity is basically the definition of G-force...). So when you used G-force I only considered the portion due to centripetal force. The G= 1/(cos bank angle) would have helped me on the right track if I just had looked at it more thoroughly. Thanks.

As a side note lots of literature during civil pilot training and also physics at universities (I carry a technical degree myself) don't use the G-force terminology.

[Holton181]

Oh right fig 15-4 pp126 :) describing the same thing.

 

 

 

second edition.

 

 

 

Indeed, but using load factor (what I'm used to) instead of G-force (see my post above regarding terminology confusion)

[borchi_2b]

About adding power. If you fly at 80knt level with 60% TRQ you will need in a 60° roll, to maintain speed and altitude 120% TRQ

[Rogue Trooper]

I feel I must mention here that Belsimtek made a conscious decision not to replicate the controls of their choppers fully in order to allow the "majority" of simmers an easy time of controlling the chopper with their desk top controllers.

This makes good sense from a sales point of view but without doubt a true sim option in the menu would be sweet.

 

Also the MI-8 only requires a touch of right cyclic to maintain a right turn, this after the main pulse on the cyclic to achieve the correct roll into the turn.

She will self level in time without the slight right cyclic.

 

Gunnar,

forward flight in the gazelle, you push the cyclic forward to start the acceleration and then centre the stick, the machine continues forward at the fixed speed you set.

This good for you?

 

 

It is really nice to hear someone else talking about the rotor head and blades as the entire way a chopper behaves!

[Gunnars Driver]

I feel I must mention here that Belsimtek made a conscious decision not to replicate the controls of their choppers fully in order to allow the "majority" of simmers an easy time of controlling the chopper with their desk top controllers.

This makes good sense from a sales point of view but without doubt a true sim option in the menu would be sweet.

 

Also the MI-8 only requires a touch of right cyclic to maintain a right turn, this after the main pulse on the cyclic to achieve the correct roll into the turn.

She will self level in time without the slight right cyclic.

 

 

That's a good approach!

In my way of thinking, DCS isn't really a simulator but a game.

Very many helos aren't that easy to fly or hover IRL(for a non trained person), at least the ones without a stab system. A flight model that allows for fun gaming without making it to hard is good.

 

 

That said, I don't have the Mi-8 module and what I said about the mi-8 flight characteristics is not a complaint towards the DCS mi-8. In the case of me saying "thats not wright" it's about that there cant be to different ways to use the stick AP on or of( and IRL stick around center for roll rate zero in a banked turn). This is just for the sake of this thread and the OP question.

 

 

We have people that never ever flew a real helo on the forum which have the DCS Mi-8 and/or the Huey and then they think they know how a helicopter fly IRL and from this they say that another DCS module isn't correct because of this or that and they really don't know what they talk about. There are also some, stating to have flown the type in question but from some statements its easy to see that they don't know what they talk about at all. For the developers its good to know how it really works, to be able to se the rubbish from 'hobby complainers' and not implement this to the module.

 

Gunnar,

forward flight in the gazelle, you push the cyclic forward to start the acceleration and then centre the stick, the machine continues forward at the fixed speed you set.

This good for you?

 

 

I dont have the Gazelle either( the friends I game with have and tried to talk me into it). I knew I had read some complaints, that's the reason I got to this part of the forum.

 

 

Yes, there are some problems with having a (joy-)stick that cant move the center position and simulate the real world stick-further-the-faster. In the Huey you loose throw, and might run out of cyclic if trimmed for Fast Forward Flight( I got that a few times befor I learnt to reset trim.). I think this way of trimming should change the expo curve instead so you can reach the cyclics 100% throw despite being trimmed for FFF.

 

 

The other way around is to have it like I saw in the clip posted in this thread, and have stick att center for trimmed pitch up/down at all times.

I would not have any problem with this. Its a good compromise I think.

Not how you fly a real helo, but then again, its not a simulator, its a game.

(I still think the DCS name is good, its a combat simulator, not a "flight simulator").

 

 

I have some hours playing around with RC helos also(long story, my brother in law….). Well, the RC helos (old fashioned) have a Bell hiller mixer with stub wings on the flybar that cancel the nose up with increasing speed.

The same behavior is selected for the electronic flybarless gyros that superseeded the real flybar.

For a RC helicopter with a transmitter where the stick also cannot be re-centered the only logical solution is to always have it trimmed with stick in center.

 

 

So, for the modules no problems.

 

But expressions like this:

If cyclic is re-centered, so would attitude.

or

In the real Gazelle (and in most part of French helicopters) a displacement of the cyclic of x cm is corresponding to a steady x degrees roll angle of the helicopter.

 

They are wrong. And when someone like the OP makes a thread with a question he deserves the appropriate answer. That at least what I think.

[Rogue Trooper]

I suggest you get the gazelle Gunnar, get it fast.

I suggest you get the MI-8 and I suggest you get it real fast.

 

 

By getting these Sims you will promote the chopper Sim community and you will offer superb experience for which we will all benefit.

 

You will not make assumptions from some bollocks chopper pilot that has some belief that his useless free ride in an R22 teetering blade machine bears any resemblance or relevance to the MI-8.

Do not take the descriptions or some video that some hunk a junk part time pilot experienced in comparison to the R22!

this is virus on this this web site!

Edited March 4, 2019 by Rogue Trooper

[Gunnars Driver]

I suggest you get the gazelle Gunnar

I suggest you get the MI-8

 

:)

 

I dont really have the time. I already got a couple pf modules that I didnt have the time to learn to use weapons etc. I’m connected to the guys developing the Bo105. I have helped, and will, to get the Bo as good as possible. Besides this, I try to keep up with the guys I do DCS with. I can only put a fraction of the time :cry:

[FragBum]

I feel I must mention here that Belsimtek made a conscious decision not to replicate the controls of their choppers fully in order to allow the "majority" of simmers an easy time of controlling the chopper with their desk top controllers.

This makes good sense from a sales point of view but without doubt a true sim option in the menu would be sweet.

 

That should be the "Game Mode" verses "Sim" mode option if it were to be done.

 

 

Also the MI-8 only requires a touch of right cyclic to maintain a right turn, this after the main pulse on the cyclic to achieve the correct roll into the turn.

She will self level in time without the slight right cyclic.

 

Next you fly it bring up the controls display you'll find you need to push and hold the cyclic for the duration of the turn then bring the cyclic back and voila it's level again. Turn AP off and it responds correctly put the Mi-8 into a bank return cyclic to neutral and the Mi8 kinda just stays there subject the aerodynamics.

 

Gunnar,

forward flight in the gazelle, you push the cyclic forward to start the acceleration and then centre the stick, the machine continues forward at the fixed speed you set.

This good for you?

 

Perhaps you might like to read up on blow back and it's effect on the aircraft in forward flight.

 

You could test this in the Huey it is at least modelled for forward flight. :music_whistling:

[FragBum]

I suggest you get the gazelle Gunnar, get it fast.

I suggest you get the MI-8 and I suggest you get it real fast.

 

 

By getting these Sims you will promote the chopper Sim community and you will offer superb experience for which we will all benefit.

 

You will not make assumptions from some bollocks chopper pilot that has some belief that his useless free ride in an R22 teetering blade machine bears any resemblance or relevance to the MI-8.

Do not take the descriptions or some video that some hunk a junk part time pilot experienced in comparison to the R22!

this is virus on this this web site!

 

Sharing the luv I see. :thumbup:

 

To be fair these guys don't take nonsense from anyone but they a extremely helpful and take time to explain stuff for those that genuinely want to learn, rather then spew forth verbal nonsense like we see from time to time.

 

Perhaps look at the link to the US test and evaluation of the Gazelle some mighty good reading there about cyclic displacement for forward flight. :D

 

Link here to post.

[Gunnars Driver]

About adding power. If you fly at 80knt level with 60% TRQ you will need in a 60° roll, to maintain speed and altitude 120% TRQ

 

 

Ehh…well. I wasn't sure how to handle this, to shoot down another statement… :cry:

Saw it earlier but was due to a VR racing game.

 

That statement isn't really true.(either).

 

 

Its airspeed depending. To try to make an easy explanation, the need for higher lift causes the induced drag to increase. There's parasite drag(drag like a car at speed =no lift) this doesn't change when increasing lift. At high airspeeds the induced drag is low, making for a less part of total drag.

--> If you are on the high side of the Lift/drag curve the torque increase is less then increased lift in percent.

---> If you are at bottom of the lift/drag curve the torque increase should be the samt as the increased lift.

---> If you are on the low side, the torque increase should be higher than the increased lift.

Ill try to show this in a graph, I think.

 

 

[EDIT]

 

The Red boxed numbers is at higher speed, 83% torque /11000kg vs 59.5% torque /6900kg. From 6900kg to 11000 is 59% weight increase (= 59% lift increase). The "cost is" only 39% torque increase.

 

The Blue boxed numbers is at bottom of L/d curve, 51.7% torque / 11000kg vs 32.5% torque /6900kg. 59% weight/lift increase, 59% torque increase. At the bottom of the L/d curve, Borchi_2b is correct.

 

The Green bexed, hover 97.3%/10600kg vs 54.5%/6900kg. 54% weight/lift increase, 78% torque increase.

 

The 2G turn needs a 100% lift increase, and at bottom of the L/d curve it will cost us double power, but at higher speeds it will not. It'll cost us more total power but as referred to the torque at 1G the increase will be lower.

 

Edited March 5, 2019 by Gunnars Driver
Added picture and calculations

[msalama]

conscious decision not to replicate the controls of their choppers fully

 

Either they did*, or their marketing is misleading. Just wonder which is it.

 

* model them fully I mean / EDIT

Edited March 5, 2019 by msalama

[Flagrum]

Either they did, or their marketing is misleading. Just wonder which is it.

 

I only know about is, that they use a work-around for the micro switches in the pedals. As consumer grade pedals are not trimmable (i.e. no FFB pedals), the sim assumes that the feet rest on the pedals if the axis is not centered.

[msalama]

conscious decision not to replicate the controls of their choppers fully

 

But then, both the Huey and the Hip with its AP / stab off do behave as explained here (i.e. cyclic kept deflected keeps the chopper rolling), so I'm not sure if I buy this either. Entirely possible that it's an Mi-8 AP bug, however.

 

And oh, in order to leave this tortured thread finally alone, please visit the following discussion if you're interested in the Hip's modelling quirks and possible inaccuracies:

 

https://forums.eagle.ru/showthread.php?t=233808

[borchi_2b]

@Gunnars Driver: The numbers of my example were only numbers for TRQ, I only wanted to explain that you will need additional 100% trq of your level flight for your 60 degree roll turn. So when you fly x speed and use for example 80% of your available TRQ, like in the huey in forward flight, you will not make any steep turns unless you pull the cyclic and reduce speed

[Gunnars Driver]

forward flight, you will not make any steep turns unless you pull the cyclic and reduce speed

 

:thumbup:

[Sephyrius]

Anyone with a FFB stick that isn't ripping their hair to shreds trying to fly in a coherent manner?

 

Handles fine with FFB off (requires 3rd party FFB forces), but with it on the pitch/roll behaviour is simply erratic, going from gentle to helluva sharp to locked-in-place almost at will.

Had this issue for over a year now (which is when I shelved it while waiting for fixes) , for as long as I can remember having the module, several threads about it, nothing seems to have changed ever since the "we're gonna stop developing FFB but at least fix what's already there" announcement.

 

No difference after using in on a brand new rig with a clean OS and game installation.

[DmitriKozlowsky]

Good video, was thinking about doing one myself, but am up in the alps away from my computer for some time. When banking in the gazelle if you engage the magnetic brake (trim), keeping the cyclic left, but centering your joystick you get a similar result as keeping the cyclic left in the mi-8. No rolling over.

 

My sentiments exactly. Cyclic in DCS: Gazelle does not feel or behave right.

[FragBum]

My sentiments exactly. Cyclic in DCS: Gazelle does not feel or behave right.

 

But the Gazelle (AP on or off) behaves the same as the Huey and the Mi-8 (with AP off) in regard to roll behaviour.

 

If you have the Huey (and or Mi8 ) you can easily prove this for yourself, the Gazelle, Huey and Mi8 (AP off) will roll with cyclic input and stop rolling when the cyclic is bought back to neutral position then either aerodynamics and or gravity and or further cyclic input will change it.

[DmitriKozlowsky]

I wanna give a shout out to the bold incredible helicopter pilot in posted video. He is the only helicopter pilot in USA to be licenced by FAA to perform helicopter aerobatics at air shows. ONLY ONE. Rolling an aircraft flying little over 100 knots, with three wings mounted on articulating hinges, is insane. Or attempting an 360 loop or an Immelman followed by 180 roll. This is what fixed wings are for. Helicopters and aerobatics got together like octogenarians and porn.

[FragBum]

I wanna give a shout out to the bold incredible helicopter pilot in posted video. He is the only helicopter pilot in USA to be licenced by FAA to perform helicopter aerobatics at air shows. ONLY ONE. Rolling an aircraft flying little over 100 knots, with three wings mounted on articulating hinges, is insane. Or attempting an 360 loop or an Immelman followed by 180 roll. This is what fixed wings are for. Helicopters and aerobatics got together like octogenarians and porn.

 

Yeah it's awesome, Chuck Aaron, this one?

 

 

 

Have you tried doing loops in the Gazelle or the Mi-8 yet?

[DmitriKozlowsky]

I don't have MI-8. I have UH-1H, KA-50, and Gazelle. In Gazelle, I have not tried it. In UH-1H , it is death, at any speed and in either roll direction. KA-50 is disk intersection every time, regardless of roll direction, power, entry speed, or collective. My theoretical understanding in KA-50. is fast fwd flight, collective flat down, roll to left. Disk intersection everytime.

[FragBum]

Yeah can only manage "a fat loop" with Huey but you certainly can throw it around a bit when near empty.

 

I don't really fly the KA-50 a lot but get the idea both rotor and or boom clearance to consider.

 

Gotta watch for neg G's and tail strike in Gazelle.

[DmitriKozlowsky]

Story and mods on BO-105 modded for aerobatics.

 

 

 

I do not understand, how making a rotorhead a rigid solid single peice allows for cyclic and collective to work. Makes no sense to me.

[Gunnars Driver]

Story and mods on BO-105 modded for aerobatics.

 

 

 

I do not understand, how making a rotorhead a rigid solid single peice allows for cyclic and collective to work. Makes no sense to me.

 

In the MBB Bo105 (and Westland Lynx) the blade ability to change pitch is still there.

So, there is a normal swash plate and pitch links for changing of pitch on the blades.

The rotor head is one solid piece of titanium, so there are no lead-lag or flapping joints.

The blades will still need to flap and move leed-lag wise, but this movement takes place in the inner part of the blade, made to flex.

 

In the video you linked you could get the idea that the helicopter Red Bull uses is very different from other Bo105. Well, the rotor head is not changed or modified. They might have added some extra equipment that other Bo105 might had from before. For example the ‘bulls balls’ on the inner part of the rotor blade is vibration dampers that is optional.

Also, the change of CG mentioned might just be to put the battery in the nose compartment.

The ones I flew already had all those options and had the envelope -1G to +3.5.

I think the “secret” part of this mods arent that secret actually. Sounds cool on youtube though :)

 

This was 1986:

 

This is also long time ago;

 

No ‘mods’:

Edited March 10, 2019 by Gunnars Driver