[REPORTED] Turn coordinator a bit slow

[frumpy]

Hi guys,

 

this guy needs about 25° bank at medium speed to get

the turn coordinator to a nearly full (one pointer-width less)

indication:

 

[ame]

[/ame]

 

To do that with the DCS version, I need about

80° bank angle.

 

So the coordinator is a bit slow, no?

[Corrigan]

I've noticed that it's very hard to fly uncoordinated, even without any rudder input at all. Is that related to this? And does the aircraft require that little rudder in real life too?

[OnlyforDCS]

I've noticed that it's very hard to fly uncoordinated, even without any rudder input at all. Is that related to this? And does the aircraft require that little rudder in real life too?

 

I think Wags mentioned a few months ago that the L39 pilots they were working with all noted that the plane required little to no rudder input, except in crosswind landing conditions.

[Corrigan]

That's great news, in that case. Always a pleasure to find out that things are more realistic than you suspected.

[frumpy]

Guys, what I was trying to say: Its a bug. The turn coordinator needle should deflect a lot more. Did the developers notice this?

[Anatoli-Kagari9]

Guys, what I was trying to say: Its a bug. The turn coordinator needle should deflect a lot more. Did the developers notice this?

 

Sorry, but I couldn't glimpse the TC in that video ?

 

I see an AH with an embedded turn coordinator ball - is that it ?

 

EDIT: Ok, saw it .... Think you're right ...

Edited December 15, 2015 by jcomm

[frumpy]

Did the developers take notice of this or should I contact them via private message?

[Anatoli-Kagari9]

frumpy,

 

since I do not ( yet ) own this module I can't run the test I am suggesting here, and since I also do not have access to the aircraft manual, I don't know what the markings in the TC are set for - I mean, what rates of turn they match...

 

But let's admit they're set for 4' rate turns ( full circle in 4 minutes ).

 

Simply level and perform a timed coordinated ( not mandatory, but should be done that way ) full turn and observe to where the TC needle points. If it's over the correct mark then the TC is ok, otherwise it isn't...

 

Last time I tried this in the UH-1H where the TC is marked for 4' std turns, if one completes a full turn with the TC needle aligned with either of the markings ( left or right ), it takes a LOT LESS than 4 minutes to complete... ( could have changed after the various updates, I'll check over Nevada ASAP... )

 

EDIT: It now works as precisely as I could tell, because it's really difficult to keep the TC needle aligned with the std marks through the full turn, but it did take near 4 minutes to complete !!!! This is excellent - they fixed that :-)

 

I used the Nevada Map, because I no longer have the helicopters installed in 1.5.2...

Edited December 27, 2015 by jcomm

[frumpy]

Hey jcomm, I'll check. The turn coordinator works a bit different than

I'm used to.

 

From the L-39 manual:

 

"It is developed to determine turn and slip directions and bank angles at speed

of 350 km/h. Angular velocity measurement limit is ±5,7 0/s, which corresponds

to 450 bank angle and speed of 350 km/h."

 

Thanks to the recent sale, I also bought the MiG-21. It's DA-200 turn coordinator is calibrated at 500 km/h.

[Anatoli-Kagari9]

Hey jcomm, I'll check. The turn coordinator works a bit different than

I'm used to.

 

From the L-39 manual:

 

"It is developed to determine turn and slip directions and bank angles at speed

of 350 km/h. Angular velocity measurement limit is ±5,7 0/s, which corresponds

to 450 bank angle and speed of 350 km/h."

 

Thanks to the recent sale, I also bought the MiG-21. It's DA-200 turn coordinator is calibrated at 500 km/h.

 

 

Thx for the additional info frumpy!

 

I am probably getting the L-39 anytime soon :-)

[frumpy]

>I am probably getting the L-39 anytime soon :-)

 

I like the L39, its got a good looking cockpit, excellent flight dynamics,

easy to handle yet capable of doing aerobatics.

 

I checked the turn coordinator again at 350 km/h. It seems to

deflect only about 2/3 of the correct value:

 

 

 

 

Who is the developer of the L39? I'll give them a headsup.

Edited December 27, 2015 by frumpy
changed pic

[derelor]

Thanks - reported as ticket #33175.

[BillyCrusher]

I checked the turn coordinator again at 350 km/h. It seems to

deflect only about 2/3 of the correct value:

 

Incorrect test.

TC calibrated for 350 km/h true airspeed. On your screenshots true airspeed is 400 km/h instead.

[frumpy]

Right you are, I was unsure about this one. The TC is still off by about the same amount.

[Anatoli-Kagari9]

Just out of curiosity, is that 2nd needle in the ASI ( the thinner one ) reading TAS ?

 

@frumpy: So, you did try again, using TAS instead of IAS, and got the same deviation, right ?

 

I had that problem with the initial release of the UH-1H, where, apart from being very difficult to fly a rate turn with the kind of hardware I have to control it, it was very far from the marked 4 minutes.... Latter versions show very near 4 minutes for a full circle, the differences being mostly due to my lousy flying :-)

 

Maybe they can fix it too for the L-39 in one of the next updates - after all, certainly no show killer, but apart from ELITE, there still has to be a flight simulator where this sort of details, more related to IFR practice, are done correctly right from the start.... :-)

Edited December 28, 2015 by jcomm

[frumpy]

jcomm - yes, the thin one is TAS, the big needle IAS.

 

Billy, I don't know how you did it? Your N1 at 94% is significantly higher

than mine. Did you do a level&stable turn without airbrakes? What version?

 

I tried again with 350 km/h TAS, level&stable. DCS 1.5, freeflight mission

at about 3000m. Did not try 2.0.

15° bank is okay, 30° and 45° is off. The higher the bank, the more

the value is off.

I was trying to fly a level turn at full TC deflection, on my L-39 it is not

possible due to exceeding the AOA limit.

 

Edited December 28, 2015 by frumpy

[BeR1]

See also the variometer in the video, this is also important. He is falling.

Edited December 28, 2015 by BeR1

[BillyCrusher]

jcomm - yes, the thin one is TAS, the big needle IAS.

 

Billy, I don't know how you did it? Your N1 at 94% is significantly higher

than mine. Did you do a level&stable turn without airbrakes? What version?

 

I tried again with 350 km/h TAS, level&stable. DCS 1.5, freeflight mission

at about 3000m. Did not try 2.0.

15° bank is okay, 30° and 45° is off. The higher the bank, the more

the value is off.

I was trying to fly a level turn at full TC deflection, on my L-39 it is not

possible due to exceeding the AOA limit.

 

I see on your screenshots (with 30 and 45 deg. bank) that slipping ball isn't centered so you need to apply right rudder a bit for coordinated turn without slip. I believe, in tnat case you'll get correct TC indication.

But anyway, I'll re-check this issue tomorrow.

[Anatoli-Kagari9]

I see on your screenshots (with 30 and 45 deg. bank) that slipping ball isn't centered so you need to apply right rudder a bit for coordinated turn without slip. I believe, in tnat case you'll get correct TC indication.

But anyway, I'll re-check this issue tomorrow.

 

 

Of course, the true TC will be indifferent to uncoordinated turns.

 

On a GA aircraft you can make a flat ( rudder ) turn if you want, and get the exact same result.... I believe the slip in the turns performed by frumpy is so negligible that I don't think it has any influence in the outcome...

[BillyCrusher]

Of course, the true TC will be indifferent to uncoordinated turns.

 

On a GA aircraft you can make a flat ( rudder ) turn if you want, and get the exact same result....

TC pointer position is related to angular velocity of turn (turn rate). With rudder you can change this rate (and yes, make flat turn also) but bank angle will correctly indicated on TC only for coordinated turn.

 

I believe the slip in the turns performed by frumpy is so negligible that I don't think it has any influence in the outcome...

Proof of the pudding is in the eating :)

[Anatoli-Kagari9]

Ok Billy,

 

I'll try it myself when I get the module :-)

 

Thx for the answers.

[frumpy]

I see on your screenshots (with 30 and 45 deg. bank) that slipping ball isn't centered so you need to apply right rudder a bit for coordinated turn without slip. I believe, in tnat case you'll get correct TC indication.

But anyway, I'll re-check this issue tomorrow.

 

Any news on this?

[BillyCrusher]

I've re-check this issue and agreed that needle deflection is a bit small. The issue is adressed now.

[frumpy]

Also happens in the ZA.

[frumpy]

Does anyone care about this?