Aces High Bulletin Board
Help and Support Forums => Help and Training => Topic started by: Badboy on August 09, 2009, 10:05:59 AM
-
Don’t get in a Flap
Some players make good use of flaps, others don’t. For the most part, we learn how to employ flaps from experience, but in some cases, even after significant experience it is still all too easy to get it wrong. One reason for this is a lack of good information. My intention in this post is to begin to help fix that.
Firstly though, some general comments on the use of flaps in air combat. It is fairly commonly known that using flaps changes the camber of the wing and that this changes both the lift and drag. Most players are aware that the lift increases, and the drag also increases, but what is important is the ratio between the increase in lift and drag and that ratio is known as the aerodynamic efficiency. Depending on the type of flaps and how much they are deflected, the influence of the flaps on the profile and induced drag in proportion to the lift can result in either an increase or decrease in the resulting aerodynamic efficiency of the wing. What that means is that the use of flaps can be good or bad in terms of the price you have to pay for the increase in lift.
What does that mean in terms of air combat? During an engagement, the differences in lift and drag are apparent by the influence on the way our aircraft can turn. Employing flaps generally results in higher instantaneous turn rates, and a smaller turn radius. However, in the case of a sustained turn, while the turn radius is always reduced, the sustained turn rate may either increase or decrease.
In cases where a particular flap deflection results in a reduction in turn radius, and an increase in the sustained turn rate, it is very important to identify that, because it can be highly desirable to fly in that configuration. However, it is more common for a reduction in turn radius to be accompanied by a reduction in the sustained turn rate. In those cases it is essential to know when you need to minimise your turn radius, or when it is more important to maximise your sustained turn rate.
The answer is this… Generally, (I need to speak in general terms because there are exceptions and I will come to that later) it is better to minimise your turn radius in a one circle fight (nose to nose turns) and to maximise your turn rate in a two circle fight (nose to tail). This is a very important point, it is so important that many players lose fights because they fail to understand the subtleties of it.
In order to make best use of the differences in radius and rate caused by the use of flaps, it is necessary to know how your turn radius and turn rate are influenced by the use of flaps in a sustained turn. That information is conveyed most readily by means of a diagram showing the turn circle for a fixed time. That way the turn radii can be seen relative to each other, and because the circles are drawn for a fixed time, the differences in sustained turn rates will be apparent because some lines will extend farther around the circle than others. You can see this by inspecting the following diagram.
(http://www.badz.pwp.blueyonder.co.uk/Files/Images/TurnF4U1D.gif)
Here you can see that the F4U1D benefits from a tighter turn radius and an increased sustained turn rate when flaps are employed. You will notice that the best sustained turn rate occurs when the flaps are deflected by two notches. That’s the best place to be in nose to tail fight, because the way to win that kind of fight is simply to win the turn rate war. You need to gain angles on your opponent until you move around the circle onto his tail. In order to do that you need to know how to maximise your sustained turn rate. The diagram above shows you exactly how to do that.
You can also see that if you deflect the flaps on the F4U1D beyond two notches, you pay for it with a reducing sustained turn rate. Notice also that once you get to four notches, the fifth and final notch gives you a slightly tighter radius with an insignificantly small reduction in rate. So for this particular aircraft, once you enter a turn fight, you should use only two notches of flaps as long as you are turning nose to tail to optimise your rate, and if the fight goes nose to nose, such as in a scissors, where you need to reduce speed and minimise your turn radius, use full flaps.
Lastly, if the situation changes don’t be afraid to work the flaps. If the fight is nose to nose and you employ full flaps as appropriate in that case, but the situation changes to one where you find your self chasing the bandits tail, don’t be afraid to reduce your flap deflection in order to improve your turn rate, and thus out turn your opponent.
Having said that, few things in life are cut and dry, and even that wisdom isn’t always safe. It all depends on the aircraft. For example, take a look at the diagram for the A6M2 shown below:
(http://www.badz.pwp.blueyonder.co.uk/Files/Images/ZekeR1.gif)
You will see that this case is very different from the previous one. Instead of the flaps producing an increase in the sustained turn rate as it did in with the F4U1D, you now notice that as the flaps are deflected the turn radius tightens up as expected, but now the sustained turn rate drops also. You can see that while there is a significant drop in sustained turn rate for the first and second notch of flap deflection, the second, third and fourth positions all have very similar turn rates.
The conclusion you can draw from this is that for this aircraft, if you want to maximise your turn rate, don’t use your flaps at all. There is no sweet spot as there was with the F4U1D. Also, if you feel the need to deflect the flaps by two notches, you might as well go all the way, because you will get a tighter turn radius and your sustained turn rate won’t diminish any farther than it already has. However, in this case the turn radii are small and the reduction in radius at full flaps is significant and that presents another problem.
Continued...
-
Previously my advice for a player in a nose to tail turn would have been to optimise turn rate, however because the circles are so small in this example, there is a danger that a player who drops full flaps may be able to pull his nose inside his opponent’s turn for a shot across the circle. If the shot succeeds, the energy sacrificed will be worthwhile, but be warned, if you go for a shot like that, if it doesn’t succeed, at worst it may very quickly prove fatal, or at best the energy lost in the attempt will haunt you throughout the remainder of the fight.
Not to mention those players who will deliberately offer the prospect of such an opportunity in the hope that their opponent will go full flaps and give up everything for a first shot opportunity. Here is an example, from a high pressure duel, where a very good and well known player, goes full flaps soon after the merge and gives up every bit of energy in the hope of a first shot opportunity. Notice how the shot is avoided with a 90° rotation and pull out of plane, and the bullets missing the tail.
www.badz.pwp.blueyonder.co.uk/Files/Films/Example1.avi
Similarly, I often see players, and surprisingly, some very good players losing fights because they don’t know how to maximise aircraft performance for the situation they are in. They simply don’t know where the sweet spot is for their particular ride. That’s often because they simply don’t have the information. They are at a disadvantage and anyone in that position can minimise their disadvantage by always attempting to take the fight one circle, in which case full flaps is almost always the right thing to do.
Unfortunately, when that is successful, as it can often be against weaker players, it is easy to become locked into that mindset and think that is the only way to fight. But when such a player meets someone who forces the fight back to a nose to tail turn and who then optimises performance for that situation, and has a proper understanding of the relationship between angles and energy, the fight can become very difficult for the player stuck at full flaps with a one circle mindset. The longer such a player allows themselves to remain in that situation, the more they continue to lose angles and energy until they become entirely defensive, or in a worst case scenario, end up like the player in the next example.
Here we see another very good, experienced and well known player in a very tense duel. This example is similar to the previous one only in as much as the victorious pilot only uses his flaps right at the end of the engagement in both cases, and then only for a few seconds. You will notice that the adversary pilot is so desperate for a quick kill, he begins to shoot early on the second merge, (despite previously agreeing rules of engagement involving no head on shots) thus signalling his intentions and allowing time for a guns defence involving a similar 90° rotation and pull out of plane as seen in the previous example.
www.badz.pwp.blueyonder.co.uk/Files/Films/Example2.avi
From that point on the Adversary pilot remains at full flaps, and by virtue of his smaller turn radius, almost gets a tail shot at the 42 second mark in the film. But this is now a nose to tail fight where sustained turn rate should win the day. At 47 seconds the Adversary begins a large low Yo-Yo in the hope of getting a shot across the circle. At the one minute mark you see that he almost gets another tail shot, but not quite! You may notice at those moments a very slight and subtle extra pitch movement in the nose, indicating that this pilot was pulling hard into stall buffet desperately trying to get the few degrees extra needed for a shot, but those excursions deeper into stall come with a drag penalty and even more lost energy. Now, this Adversary has used up all of his energy in a number of failed gun opportunities and despite the smaller turn radius is now in a nose to tail turn where sustained turn rate is what counts.
Now we get to the exciting part.
At 1 minute 11 seconds the adversary pilot has only just failed to make yet another shot, he has a low aspect angle with about 90° angle off, he has his opponent in his forward up view and you can be certain that at this point he felt as though he was in a very strong position. But watch what happens next… Using the energy and sustained turn rate advantage acquired through correct use of flaps, our subject now drives around the circle, and uses flaps just at the last moment to clinch the kill, and it’s all over. An important point here is that even though it looked as though the adversary pilot here appeared to get fairly close to a shot on a number of occasions, there was never any real danger, because if it looked at any point as though the adversary was going to pull enough lead for a shot, there was still the option to rotate 90° and pull into the vertical. Don’t forget, this pilot wasn’t using his flaps, he was faster, he had an energy advantage and still had the option to use the vertical, and drop flaps if needed. He could still execute a similar endgame as seen in the previous film.
Our adversary pilot in this example was desperate for a kill, an attempted HO, followed by two near miss gun opportunities and he went from what he would have perceived as a strong position one moment, and the next moment his opponent had driven around the circle and was gunning him from behind… No need to guess at the surprise and bewilderment going through our adversary pilot’s mind at the last moment, and even less surprising that we often see so many accusations flowing freely at such times, particularly when the adversary has no idea how such a thing just happened.
When asked how it happened, the answer is simple, just learn the relationship between angles and energy, know your aircraft performance in every configuration from clean to full flaps by using diagrams like the ones I posted earlier, and most importantly… Don’t get in a flap.
Badboy
PS
For rate and radius diagrams of the Brewster and I-16 check out the following thread.
http://bbs.hitechcreations.com/smf/index.php/topic,270762.0.html
-
Nice post :aok
-
Excellent info thx for the post! :aok
-
Badboy, that was an IMMENSELY helpful article for me. One of my biggest problems is going too "flap happy," in Corsairs, and it's great to read about other options. Thank you! :aok
Would I be right to assume the -1A is similar?
Can you help me figure out what I need to do to watch these films though? Something about a codec?
Thanks again,
:salute
-
Hi,
Nice article, I am having trouble seeing the films though, what can I use to view them? win media says it can't play them and also the film viewer that came with AH won't play them.
I use 2 notches of flaps in the -1 but I am unsure how hard to pull on the stick. Not enough pull and my opponent beats me in the turn, too much and I stall the plane. Must be a sweet spot there too. I gave it as much elevator as I could last night beat my opponent in the turn then crashed as I stalled it.
-
for those having trouble watching films try these links to the K-Lite Mega Codec pack ( free download )
http://www.google.com/search?hl=en&q=k-lite+mega+codec+pack+download&aq=8&oq=K-Lit&aqi=g10
for a free video viewer, my opinion their are none much better than this free viewer:
http://www.google.com/search?hl=en&q=vlc+player+free+download&aq=1&oq=VLC+Player&aqi=g10
both of these links are Google search pages with multiple download links..........pick your choice......
Note: although with the Video & Audio Mega codec pack installed.you should have no problems viewing these films with Windows Media Player
good luck
The F4U-1 turn rate / turn radius is somewhat different than the F4U1D...... IIRC the turnrate stays near constant, although the turn radius will tighten up with each notch of flaps.......... maybe Badboy can throw up a chart for it......
-
excellent post. Are there charts somewhere for the whole plane set?
-
great help badboy thnks for the post. :rock
-
TC is correct, the turn rate will more or less remain the same, but the radius will change:
Turn Radius with Full Flaps
F4U-1A - Not sure of the numbers, but I want to think it's somewhere in the vicinity of 419-422ft
F4U-1 - 425ft
F4U-1D - 427ft
F4U-4 - 428ft
F4U-1C - 443ft
I don't know the turn rate comparisons, but I would think the F4U-4 would be on top, followed by the 1A, 1, 1D and 1C in that order.
Incidentally, I always subconsciously try to avoid dropping more than two notches of flaps in the F4U. Interesting to see there's a technical/aerodynamic justification of it.
-
Awesome post, I've noticed similar traits in the A6M5b but I don't have a chart to back it up, just feel from flying it so long. Do you by chance have a graph for the A6M5b showing the best use of flaps?
-
The old "do whatever feels right" flap system works well with me. :aok
-
Thanks for the codec link TC I could not play these videos and also the scenario films Kermits makes with my stock vista home premium.
-
Is there sound in those vids? I don't have any when I watch them. Perhaps my codecs need updated too.
-
are there any other graphs like this for other AC? and if so where are they?
-
Any sound to the codecs? Have none, at present! :mad:
-
No sound on mine either, there likely never was any just to keep the file size down.
-
No sound on mine either
Yep, no sound on either film.
Badboy
-
Awesome post, I've noticed similar traits in the A6M5b but I don't have a chart to back it up, just feel from flying it so long. Do you by chance have a graph for the A6M5b showing the best use of flaps?
The A6M5 is similar accept for that last notch, in as much as your sustained turn rate drops all the way down to full flaps, as shown below.
(http://www.badz.pwp.blueyonder.co.uk/Files/Images/A6M5R.gif)
Badboy
-
Would I be right to assume the -1A is similar?
The F4U1 and F4U1A behave slightly differently.
Here is the flap comparison for the F4U1A
(http://www.badz.pwp.blueyonder.co.uk/Files/Images/F4U1AR.gif)
Here you notice that once again you have an optimum sustained turn when two notches of flaps are deflected.
However, the F4U1 flap comparison shown below confirms what TC said in an earlier post:
(http://www.badz.pwp.blueyonder.co.uk/Files/Images/F4U1R.gif)
In this case you can see that when you get to two notches, you can reduce your turn radius even more by deflecting the flaps all the way, with no further loss in sustained turn rate. In practical terms what that means is that while you might stay at two notches of flaps in a nose to tail turn in the F4U1A, in order to optimise sustained turn rate, in the F4U1 you could deflect full flaps as the diagram above shows.
Many thanks to TC for following up on that point for me!
Can you help me figure out what I need to do to watch these films though? Something about a codec?
Did the link TC gave you help?
Badboy
-
like Steve said where can we find these chart? sry if i missed the answer its late in korea :)
-
Awesome post Leon, thanks!
Assuming you have all the charts made already, is there anyway you could post this information for the entire fighter planeset? If you don't have the charts already then don't worry, wouldnt want to have to put you through that :)
-
Thanks for the help, BadBoy :aok
The link TC gave me should probably work, but when I first saw it, I was a bit paranoid about installing *anything* on my computer, as I was having an issue or two with the game. It's clear skies now, though, so I'll have to check it out.
-
Badboy,
Thanks for the charts. Flying the 1 and 1a for years and never expected to see that kind of flap performance difference. very interesting stuff :aok
:salute
BigRat
-
Nice post Badboy! :salute
-
The A6M5 is similar accept for that last notch, in as much as your sustained turn rate drops all the way down to full flaps, as shown below.
(http://www.badz.pwp.blueyonder.co.uk/Files/Images/A6M5R.gif)
Badboy
Thanks a ton. :salute
-
Great post I get everything you said. I've been frustrated with knowing these concepts but be able to look up detailed plane performance stats. There are many very eye opening table that could be created with the proper data.
I've combed the AH site looking for exactly this kind of data but I can't find it if it is available.
So where does one get The data!!???
-
So where does one get The data!!???
We get our data in the same way that real aircraft data is obtained, by flight testing. For the diagrams posted above you only need to know the turn radius and turn rate, and that only requires one simple flight test.
The instructions for carrying out the test, and a tool for calculating the required values are available in this download:
Download Badboy's BootStrap Calculator (http://www.badz.pwp.blueyonder.co.uk/Academy/AH_BootStrap.zip)
Hope that helps
Badboy
-
:aok Good thread
-
Badboy,
This will be more fun than I thought! Looking forward to my own flight testing!
You the man.
Vinkman
-
great info on flaps, i love the way this game always has more to learn.
-
Good stuff as always Badboy ... Should be posted or linked to the AHwiki page
Btw do u still have the EM charts for the plane set? Would like to see
the 38's.
Thanks
Tokenjo
-
Badboy,
how did you get these figures? I've always wondered how people came with up these exact numbers for the game. If its something that others could do, then maybe we could all figure out the flaps sweet-spot for all of our fav rides.