Rudder effectiveness

[CoBlue]

FYI, every airplane in the world will do a flat turn, and any RL pilot will confirm this no matter what airplane he/she has flown.

As a RL pilot I can confirm that without any doubt:thumbup: This is flight lesson nr 1, very basic stuff!

On some airplanes it was recommended to keep your heading with rudder inputs & wings level after rotation on x-wind take-offs.

[Djent33]

It’s nice that pilots know that it turns.

In short, you pull on the stick to make the wing hit the wind at an angle..

Now the rudder is hitting the air at an angle and its flap forcing it left but the rudder angle is forcing right. Equilibrium? No it should turn a bit more but it’s not a basic stuff when you flying sideways IMO, net force should pull it all the time.

[AH_Sid]

 

If the rudder is correctly modelled, can anyone give me any tips on how to improve my cross-wind landings?

 

I can just about get it down (and stay on the runway locking a brake), but so far I wouldn't describe it as 'Adequate control'.

 

This is at 13 Meters per second / 25.27 Knots

 

[iFoxRomeo]

Cofcorpse, sorry for being insistent. But could you comment on the video please. Especially regarding the turn indicator(except for the KA-50 which has no turn indicator). It has a duration of only 3 minutes.

 

Is the Sabre (and Eagle) supposed to have nearly ZERO deflection on the turn indicator with pedals fully applied to one side, while all other aircraft(except the Huey) then show half scale(and more) deflection?

 

Thank you.

 

Fox

 

OK. I maybe missed it, but is there some concrete data about correct behaviour of F-86F? If there isn't, why do you assume that something is wrong?

 

And, F-15 is discussed in another thread.

 

Cofcorpse, I made a comparison video of various DCS aircraft. And there you will see, why people find it hard to belive, that the sabre´s and eagle´s yaw behaviour is supposed to be correct. Watch the turn indicator. The Huey´s, Eagle´s and Sabre´s turn indicator show nearly Zero, when they shouldn´t.

That similar behaviour probably led to the following idea...

 

""Originally Posted by Chappie What I am thinking. They produced helicopter FMs and just slapped em on the ED F-15C and the F-86. Then they modified the parameters. Makes sense since a Helo can perform a 360 turn while never deviating flight path2""

 

These aircraft turn so slowly that it seems to be incorrect.

 

The video is not listed in YT.

 

 

 

Fox

 

p.s. I love the Sabre, and this issue is no showstopper for me. But would be nice if it could be clarified, if this is wrong or not.

[cofcorpse]

Cofcorpse, sorry for being insistent. But could you comment on the video please. Especially regarding the turn indicator(except for the KA-50 which has no turn indicator). It has a duration of only 3 minutes.

 

Is the Sabre (and Eagle) supposed to have nearly ZERO deflection on the turn indicator with pedals fully applied to one side, while all other aircraft(except the Huey) then show half scale(and more) deflection?

 

Thank you.

 

Fox

 

Thanks for the video. Some remarks:

1) I think it's not correct to compare jet and prop planes. There are big differences.

2) I think it's not correct to compare jets and helicopters. There are big differences.

 

We will recheck and prepare explanation of such behaviour.

[iFoxRomeo]

Thanks for the video. Some remarks:

1) I think it's not correct to compare jet and prop planes. There are big differences.

2) I think it's not correct to compare jets and helicopters. There are big differences.

 

We will recheck and prepare explanation of such behaviour.

 

Thank you very much.

 

Fox

[bkthunder]

 

We will recheck and prepare explanation of such behaviour.

 

If you can explain that, I will burn my pilot's license together with all the aviation manuals I've ever read.

 

Joking aside, I'm glad you have finally decided to look into the issue. :thumbup:

[cofcorpse]

If you can explain that, I will burn my pilot's license together with all the aviation manuals I've ever read.

 

Joking aside, I'm glad you have finally decided to look into the issue.

We're looking into this issue since we released Sabre. And I doubt that you fly F-86F, or am I wrong?

 

P.S. what aircraft do you fly?

[audax]

Do you have to be so aggressive, cofcorpse?

[cofcorpse]

Do you have to be so aggressive, cofcorpse?

I'm sorry, didn't want to be rude. But you must understand - if there is no data, there is unlikely any changes will be made. (Unless we find any mistake)

Every plane flies different.

[CoBlue]

I'm sorry, didn't want to be rude. But you must understand - if there is no data, there is unlikely any changes will be made. (Unless we find any mistake)

Every plane flies different.

Have you read post #33 ? every airplane can perform a flat turn. What data do you want?

[cofcorpse]

Something more concrete than

every airplane can perform a flat turn.

 

For example, level flight, no roll, 1000ft, 400knots CAS, full fuel, full rudder defection - 10 degrees per second turn rate.

[OnlyforDCS]

I dont get it, Rodd is the Sabre is not able to perform a flat turn in the sim?

 

(serious question, dont have the Sabre but I was thinking of getting it at some point since I have both the Huey and Mi8 )

Edited November 28, 2014 by OnlyforDCS

[bkthunder]

We're looking into this issue since we released Sabre. And I doubt that you fly F-86F, or am I wrong?

 

P.S. what aircraft do you fly?

 

I don't fly the F-86 (though my grandfather did..). I currently fly a Piper Aztec E and still fly a Pitts S-2C from time to time. In the past I flew Cessna 172 & 182, Extra 230, RV-4, Pioneer 330 and tried a bunch of other airplanes including some 20 hrs in a KC-10 sim at Travis AFB. In total I have about 3000 hrs since I got my license in 2004.

 

 

Now on to the important stuff: you modeled the F-86 based on incomplete data, you admitted yourself that you would like to have this information:

level flight, no roll, 1000ft, 400knots CAS, full fuel, full rudder defection

 

Let me ask you, have you got data for each and every other altitude/ speed / condition / control surface deflection?

Since you model something only if you have data, I suppose you do.

Still, if you were missing data to such an extent that it didn't allow you to model the rudder and yawing behavior, why on earth did you knowingly decide to sell a module that's missing such a HUGE part of the flight model?? (yes HUGE, because this has consequences on the fuselage as well).

 

 

BST: "Here's your car"

Customer: "Cool, but the reverse gear doesn't do anything, how do I park this thing??"

BST: "Erm...we didn't have data that showed how this car would drive backwards at 2.5 mph on a flat tarmac with 12.5 degrees celsius OAT..."

Customer: "But surely all cars that have a reverse gear can drive backwards!?!"

BST: "Well, I haven't seen any hard data to officially prove that THIS particular car would drive backwards even though it has a reverse gear..."

[cofcorpse]

 

I think this discussion is going to simple dispute.

 

You (our customers) stated that there is some problem. We are doing our best to find the solution (whatever it is).

[bkthunder]

I think this discussion is going to simple dispute.

 

You (our customers) stated that there is some problem. We are doing our best to find the solution (whatever it is).

 

I am very happy that you try to find the solution, and also that you recognize there is a problem. Surely I think some of your previous statements about this issue don't make much sense, but as long as you fix it I don't care how you do it :smilewink:

[NineLine]

 

Now on to the important stuff: you modeled the F-86 based on incomplete data, you admitted yourself that you would like to have this information:

 

I think that information was requested because it can be used to confirm the FM, its not like there is a table of data, and that row is blank because they didnt have the information, its probably only requested to verify either there is a mistake or there is nothing to fix, if that makes sense.

[BitMaster]

By the sake of this topic, isn't there ANY former F-86 pilot we can ask and get 1st person info from battle hardened pilots that flew that thing to and beyond the limits.

 

It can't be that hard to get a true word on that from veterans.

 

Maybe bkthunder can ask his grandpa if he is still with us.

 

 

Cmon, it's no rocket science to find out if the rudder was effective or not and to what extend you could land at xwind scenarios.

 

...and yes...any airplane can make a 360 with rudder and elevator only if you aren't stupid, some planes don't have more than that and flew pretty well ( early days ) and gliders at certain flight phases do complete multiple 360 screwing themselves UP in a thermal upwind with rudder and split aileron ( ok here some aileron on 1 wing half is used too, but it works without it pretty well too )

 

 

As a customer of 2 BST modules, I have to say, I didn't like the tone BST approached it's customers in this thread, I will think twice before I buy again, sorry. You should never forget who pays your bills. I say this as a business man that sometimes has to chew things too and not make customers turn away.

 

Bit is a bit disappointed on how this thread went

[NineLine]

I didn't like the tone BST approached it's customers in this thread

 

I'm not sure where you saw them take a poor tone, couple things, there are non native English speaking people in this thread, sometimes things are lost in translation, including tone of a post. Also, its been said many times in many threads, in order to report something you need to show good solid proof that you know there is a problem... thats all that was asked here. It can be especially challenging with the FM, unless you have experience piloting a real F-86, its hard to disprove something with the FM, unless you can show numbers or data that isnt correct...

 

So lets all take a deep breath and try and focus on the topic and determining if there is an issue.

 

And actually, I think FM creation is pretty close to rocket science ;)

[CoBlue]

Something more concrete than

For example, level flight, no roll, 1000ft, 400knots CAS, full fuel, full rudder defection - 10 degrees per second turn rate.

I don't have those figures, but shouldn't you be able to calculate those numbers yourself????

I mean Belsimtek states this: "During the simulation, complex calculations of the characteristics of the aircraft constituent elements are performed taking into account their mutual influence in all the range of local angles of attack and of sideslip (including beyond stall angles as well), local ram-air flows and Mach numbers taking into account control deflections, and the level of destruction of certain elements of airframe and control surfaces.

 

I dont get it, Rodd is the Sabre is not able to perform a flat turn in the sim?

(serious question, dont have the Sabre but I was thinking of getting it at some point since I have both the Huey and Mi8 )

Correct Sir. It doesn't perform a flat turn, with full rudder & wings level it flies straight, in a yaw, without changing heading.

 

I don't fly the F-86 (though my grandfather did..).

Let me ask you, have you got data for each and every other altitude/ speed / condition / control surface deflection?

Since you model something only if you have data, I suppose you do.

Still, if you were missing data to such an extent that it didn't allow you to model the rudder and yawing behavior, why on earth did you knowingly decide to sell a module that's missing such a HUGE part of the flight model?? (yes HUGE, because this has consequences on the fuselage as well).

BST: "Here's your car"

Customer: "Cool, but the reverse gear doesn't do anything, how do I park this thing??"

BST: "Erm...we didn't have data that showed how this car would drive backwards at 2.5 mph on a flat tarmac with 12.5 degrees celsius OAT..."

Customer: "But surely all cars that have a reverse gear can drive backwards!?!"

BST: "Well, I haven't seen any hard data to officially prove that THIS particular car would drive backwards even though it has a reverse gear..."

Very good question & a very good comparison with the car:thumbup: This issue is really basic!

 

I think this discussion is going to simple dispute.

You (our customers) stated that there is some problem. We are doing our best to find the solution (whatever it is).

Please do that, thank you:smilewink:

 

Also take a look at the pictures of the full rudder deflection & think for yourself, should this do anything aerodynamically or not?

Edited November 29, 2014 by CoBlue

[NineLine]

I don't have those figures, but shouldn't you be able to calculate those numbers yourself????

I mean Belsimtek states this: "During the simulation, complex calculations of the characteristics of the aircraft constituent elements are performed taking into account their mutual influence in all the range of local angles of attack and of sideslip (including beyond stall angles as well), local ram-air flows and Mach numbers taking into account control deflections, and the level of destruction of certain elements of airframe and control surfaces.

 

Well I think that is what cofcorpse is trying to get across, they enter all the properties of the aircraft, and then see what they get with the FM, his question to you and others I believe is where do you get your information that it is wrong. He never says that you guys are wrong, but in order to know what to fix, you need to know what is wrong.

 

Basically what is the proof that it isnt operating as it should. On BST's side, they entered all the data they had for the aircraft, and based on other FMs done, you should see it operate as it did in real life. Again, not saying something doesnt need tweaked, but you cant guess at these things...

[NineLine]

Guys, thread cleaned a little, please keep it on the topic of the Sabre rudder. Thanks.

[Flagrum]

Well I think that is what cofcorpse is trying to get across, they enter all the properties of the aircraft, and then see what they get with the FM, his question to you and others I believe is where do you get your information that it is wrong. He never says that you guys are wrong, but in order to know what to fix, you need to know what is wrong.

 

Basically what is the proof that it isnt operating as it should. On BST's side, they entered all the data they had for the aircraft, and based on other FMs done, you should see it operate as it did in real life. Again, not saying something doesnt need tweaked, but you cant guess at these things...

But that is the whole point of this "dispute" or maybe misunderstanding, I think.

 

As far as I understood this thread so far (if I say "we" or "us" I mean "those who report this bug"):

- the aircraft does not change the heading when trying to perform a flat turn. It only yaws. This is the proof as this is physically not possible.

- how the aircraft should exactly perform (i.e. which exact turn rate under what exact flight parameters) would describe the solution for the issue, but is not known by us.

 

We would gladly help to sove the problem, but atm all we can do is to point out that there IS a problem.

 

If BST thinks that the modelling is correct, then please explain it - as it seems to be a very unintuitive behaviour of the aircraft. Otherwise correct the issue - and where we can, we will be glad to help to research and whatnot.

 

So where are we now in this discussion? Do we all agree that there is something wrong? And that we need better data to know how to make it right?

Edited November 29, 2014 by Flagrum

[Gargoyle1]

Hm,

 

I haven't noticed this bug. I'll go test it out real quick :joystick:

[bkthunder]

So where are we now in this discussion? Do we all agree that there is something wrong? And that we need better data to know how to make it right?

 

Thanks, your post is very clear.

I think what is freaking me / us out is that BST is still waiting for data to see IF they are wrong or not.

But the point is that, despite what BST thinks that all airplanes fly differently, there are some things that are common to EVERY airplane.

 

It is widely accepted and proved that wings produce lift on ALL airplanes

It is widely accepted and proved that ailerons will make ALL airplanes roll

It is widely accepted and proved that elevators will make ALL airplanes change their pitch

 

and you guessed it...

It is widely accepted and proved that rudders will make ALL airplanes yaw and change their heading.

 

I mean, airplanes have been developed on these basic principles since 1903. If you're doubting that rudders work the way they work, then you're doubting basic principles of physics and as a FM developer that doesn't make you look too good.

 

I truly appreciate the fact that you want to model things based on real data, but if you don't have that data, you still have to do the best you can and calculate it yourself / get pilot input etc. But you can't leave the FM as it is and advertise it as high fidelity. It has to be fixed.