Why's and How's of a Coordinated Turn - Page 2 - ED Forums
 


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Old 09-10-2019, 01:41 PM   #11
Nealius
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I find the "step on the ball" principle to be only valid when doing Cessna turns. Any time I'm not doing gentle turns I ignore the ball and just watch what the nose is doing, which is much easier to do in VR.

During aerobatics the ball doesn't make any sense; not just the Tomcat, but in the Tomcat and all the warbirds too. When doing an aileron roll, let's say to the left, the ball slams to the left for the first 90 degrees of the roll, and it slams to the right the second 90 degrees of the roll. However, if you actually step on the ball as it is indicating, you will be yawing all over the place during your roll. Another example is when snapping into a high bank angle. Going left again, the ball will slam to the left side even if I give max possible rudder deflection.

With the Tomcat in particular, the ball's movements are extremely delayed. I'll do a roll which looks nice and straight when looking over the nose, but the ball will be oscillating back and forth even after I've flown straight and level for a good 5 seconds, with the nose dead-straight and rock-solid.

It seems like the ball is really only useful when you are already established in a bank. Other than that, it's best to look over the nose and do it by feel.
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Old 09-11-2019, 06:33 AM   #12
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Originally Posted by Jester2138 View Post
e.g. if you know your nose is pointed at the mountain top, then as you roll you just watch the mountaintop for slip and move your feet to make sure it rotates exactly about that axis and no other.
Ok, I tried this, and to be honest, I'm confused.

If my nose is pointing at a mountaintop and I bank to the left to initiate a turn, the mountaintop immediately moves away from the nose. So with the lineup lost between the nose and the mountaintop, how do I keep track of things. The axis of rotation is somewhere in the direction of the horizontal component of my lift vector (and perpendicular to it) ...

I know this must sound so stupid that it might seem like I am trolling ... but I'm not!
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Old 09-11-2019, 08:50 AM   #13
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I sometimes find that the turn-and-slip indicator shows that the opposite rudder from what I expect.
Yes. The Tomcat has both adverse and proverse yaw depending on your AoA. As a rule of thumb, at higher speeds it has proverse yaw and lower speeds adverse.

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If my nose is pointing at a mountaintop and I bank to the left to initiate a turn, the mountaintop immediately moves away from the nose. So with the lineup lost between the nose and the mountaintop, how do I keep track of things. The axis of rotation is somewhere in the direction of the horizontal component of my lift vector (and perpendicular to it)
Yes, because you're not coordinated. It's easier to explain in video, as Jabbers does here (the explained theory is essentially correct, although his demonstration is backwards - he's trying to counter adverse yaw (left bank with left rudder) while experiencing proverse yaw, which is why he's totally uncoordinated the whole time if you watch his ball lol)

https://youtu.be/b5opjCygZug?t=227

To explain what he should have been doing: at low AoA such as in his video, when you roll left, you put in a little right rudder. At high AoA (11+) such as when dogfighting, when you roll left, you put in a little left rudder (like a Cessna/warbird).

Something worth noting is that being perfectly coordinated 100% of the time is not necessary. It's a mark of good airmanship, sure, but you're not going to crash just because you've got a bit of a slip going on in a standard turn. When you're dogfighting, though, you should be worried about it a lot more. I find my feet moving all over the place in a dogfight. At really high AoA you're banking primarily with rudder, not aileron!

Last edited by Jester2138; 09-11-2019 at 09:02 AM.
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Old 09-11-2019, 10:45 AM   #14
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Hello,

I am thinking the ball in the Tomcat is really sensitive. It is affected very much with even the slightest amount of rudder input. I have the crappy Thrustmaster rudder pedals so that may not help, but in real life flying, when doing high bank angle maneuvers you need quite a quick on the rudder to keep coordinated when entering the turn. The only time I got a sensitive ball was flying ultralight which had very few inertia on the yaw axis. I may be wrong but I guess an F14 would have quite heavy inertia on the yaw axis and far more stable ball as a consequence.

Pierre
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Old 09-11-2019, 05:32 PM   #15
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Originally Posted by Jester2138 View Post
Yes. The Tomcat has both adverse and proverse yaw depending on your AoA. As a rule of thumb, at higher speeds it has proverse yaw and lower speeds adverse.

Yes, because you're not coordinated. It's easier to explain in video, as Jabbers does here (the explained theory is essentially correct, although his demonstration is backwards - he's trying to counter adverse yaw (left bank with left rudder) while experiencing proverse yaw, which is why he's totally uncoordinated the whole time if you watch his ball lol)

To explain what he should have been doing: at low AoA such as in his video, when you roll left, you put in a little right rudder. At high AoA (11+) such as when dogfighting, when you roll left, you put in a little left rudder (like a Cessna/warbird).
So it's proverse yaw at low AoA (requiring opposite rudder) and adverse yaw at high AoA (requiring rudder in same direction as turn)? I thought it was the other way around. And that may explain some of my confusion!

The other confusion I had with the fixed-mountaintop exercise: from the video it seems we use it to practice rolling/banking, but not actually turning. That is, your heading stays the same and that's how you have a static point of reference. I thought we were using the distant feature as a reference while actually turning, i.e. changing heading.

In another thread, Victory mentioned that rudder input is required only with lateral deflection of stick, then as this is relaxed and you pull back to turn, you remove the rudder input. This is with respect to the break turn on landing, but if it applies more generally then I can see the above exercise helping generally too. However, if you want to check/practice coordination throughout an actual turn (i.e., while your heading changes) --- which was what I was trying to do --- then I guess the turn-and-slip indicator is all you have?


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Originally Posted by Jester2138 View Post
Something worth noting is that being perfectly coordinated 100% of the time is not necessary. It's a mark of good airmanship, sure, but you're not going to crash just because you've got a bit of a slip going on in a standard turn. When you're dogfighting, though, you should be worried about it a lot more. I find my feet moving all over the place in a dogfight. At really high AoA you're banking primarily with rudder, not aileron!
When in dogfighting/BFM, I usually just "go with the flow", working all controls (stick, rudder, throttle) simultaneously without thinking about coordination etc. to just get pointed where I want to point. I do not actually come off too bad because of my previous (simulated) warbird experience. But just want to be sure I am doing things "correctly" by the numbers/book as well as "right" by the feel/intuition, if you know what I mean. So I would like to build up my airmanship skills.

The F-14 is the first DCS jet that I've tried to learn how to fly fully as my typical sim experience is otherwise 50% helos / 50% warbirds. The simulated warbird experience has help develop a lot of intuition with regards to rudder especially, but I find that it is only partially translating to the F-14. And, weirdly, I love that! It is presenting such a different and such an enjoyable challenge! It honestly is the most fun I've had learning to fly ....

Last edited by Bearfoot; 09-11-2019 at 05:38 PM.
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Old 09-11-2019, 06:04 PM   #16
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Quote:
Originally Posted by Jester2138 View Post
Yes. The Tomcat has both adverse and proverse yaw depending on your AoA. As a rule of thumb, at higher speeds it has proverse yaw and lower speeds adverse.



Yes, because you're not coordinated. It's easier to explain in video, as Jabbers does here (the explained theory is essentially correct, although his demonstration is backwards - he's trying to counter adverse yaw (left bank with left rudder) while experiencing proverse yaw, which is why he's totally uncoordinated the whole time if you watch his ball lol)

https://youtu.be/b5opjCygZug?t=227

To explain what he should have been doing: at low AoA such as in his video, when you roll left, you put in a little right rudder. At high AoA (11+) such as when dogfighting, when you roll left, you put in a little left rudder (like a Cessna/warbird).

Something worth noting is that being perfectly coordinated 100% of the time is not necessary. It's a mark of good airmanship, sure, but you're not going to crash just because you've got a bit of a slip going on in a standard turn. When you're dogfighting, though, you should be worried about it a lot more. I find my feet moving all over the place in a dogfight. At really high AoA you're banking primarily with rudder, not aileron!
Assuming what you say is correct (and I have no reason to think otherwise, in fact I agree and it's my experience as well) and the turn-and-slip indicator is modeled correctly in the HB F-14, then almost no-one of the more well known DCS-Youtubers is flying correctly, and coordinated using the t-s indicator. They just pretend they know it seems, talking about how one should use the rudder a lot while in fact I almost never see them fly coordinated, judged by the t-s indicator.
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Old 09-11-2019, 06:51 PM   #17
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There's a very big difference between knowing what adverse/proverse yaw are and being proficient at dealing with them. Considering the famous youtubers (e.g. Ralfi and Jabbers) tend to mostly fly the F18 (and F15 in the past) and they do not have formal training, I wouldn't be surprised if they were doing lots of things wrong
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Old 09-12-2019, 12:34 AM   #18
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I have still yet to find any video footage, real or DCS, of a centered slip ball during an entire aileron roll or when snapping into a high AoB. Until I see such a video, I'm going to stick by my experience (in DCS) of the slip ball being accurate only in gentle turns.
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Old 09-12-2019, 10:48 AM   #19
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Low aoa is adverse yaw, so when you stick left you rudder left also.

High aoa don't use the stick for roll! Use rudders only.

This way you don't need to think about reversing your rudder usage depending on aoa... These planes are designed to be as simple as possible (but not too simple) so you can concentrate on the kill.
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Old 09-12-2019, 05:48 PM   #20
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Quote:
Originally Posted by Jester2138 View Post
As a rule of thumb, at higher speeds it has proverse yaw and lower speeds adverse.
when you roll left, you put in a little right rudder. At high AoA (11+) such as when dogfighting, when you roll left, you put in a little left rudder (like a Cessna/warbird).

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Low aoa is adverse yaw, so when you stick left you rudder left also.
Yikes. Which is it?


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Originally Posted by Jester2138 View Post
At really high AoA you're banking primarily with rudder, not aileron!

Quote:
Originally Posted by METEOP View Post
High aoa don't use the stick for roll! Use rudders only.

This way you don't need to think about reversing your rudder usage depending on aoa... These planes are designed to be as simple as possible (but not too simple) so you can concentrate on the kill.
Agreed! In fact, I find myself using rudder roll at low AoA / high-speeds as well. Whether "correct" or "incorrect", it feels right? Not so much in BFM but when practicing flying in "Star Wars canyon" runs (e.g., following rivers through valleys in the Caucasus).
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