Aces High Bulletin Board
Help and Support Forums => Aces High Bug Reports => Topic started by: GScholz on March 10, 2014, 08:37:20 PM
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Was very surprised to test and find that the P-38's dive recovery flaps do not produce drag. Top level speed is not affected by deploying these flaps.
(https://dl.dropboxusercontent.com/u/26232318/AH/p-38-dive-flaps-bug.jpg)
I'm pretty sure something that big and uncompromisingly flat is going to produce a lot of drag. Right?
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Ooh good find! :aok
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Yeah hitech will fix this in the next millennium.
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It wouldn't effect top speed like a dive brake would.
ack-ack
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It must produce drag, thus it must affect top speed. They couldn't make a bomb pylon drag free, but what is in effect an under-wing spoiler was magically drag free?
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It wouldn't effect top speed like a dive brake would.
ack-ack
Not like a dive brake yes but it would effect top speed. Alter the skin shape and you alter the drag coefficient one way or the other albeit ever so slight. It could be only be one tenth of an MPH or it might be two or three. That we don't know until some one finds the missing piece of information like a performance retest of the J with and without the device. Till then, no bases for a change.
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More like several tens of mph, at least. A single center line ord pylon on a WWII fighter reduces top level speed by 3-5 mph, or more.
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More like several tens of mph, at least. A single center line ord pylon on a WWII fighter reduces top level speed by 3-5 mph, or more.
Even if that were so, the device is to be used in a dive, not normal level flight. In a dive the max speed is only limited by man and machine. Still a mute point.
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It must produce drag, thus it must affect top speed. They couldn't make a bomb pylon drag free, but what is in effect an under-wing spoiler was magically drag free?
The dive flap is extended to 35 degrees per the pilot manual. It's not 90 degrees like a spoiler. I don't know what it adds to the drag coefficient.
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An excerpt from the P-38L's pilot manual was posted in the aircraft forum:
"The dive recovery flaps which are installed under the wings between the booms and the ailerons, restore the lift to this portion of the wing and thus cause the uncontrollable nose heaviness to occur at a higher speed. The flaps also add some drag to the airplane, which in conjunction with the higher allowable dive speed, permits safe dives at a much steeper diving angle. The dive recovery flaps should be extended before starting the dive or immediately after the dive has started before a buffeting speed has been reached. If the airplane is buffeting before the dive recovery flaps are extended, the buffeting will momentarily increase and then diminish. With these flaps extended, the nose heaviness is definitely reduced but the diving speed should never be allowed to exceed the placard by more than 15 or 20 mph. With the dive recovery flaps extended before entering the dive, angles of dive up to 45° may be safely accomplished. Without dive recovery flaps extended, the maximum angle for extended dives is 15°."
Note that the flaps do not allow for an increase in dive speed of more than "15 or 20 mph" while allowing an increase in dive angle of 30 degrees (from 15 degrees without flaps to 45 degrees with flaps). That takes drag... and a lot of it.
Not 90 degree dive bomber speed brake drag of course, but 45 degree dive bomber speed brake drag...
So... All the data needed is right there. With the dive flaps extended the P-38L should be able to safely dive at 45 degrees, but the top dive speed should only be 15 to 20 mph more than in a 15 degree dive without dive flaps.
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The dive flap worked by reducing buffeting and preventing the center of pressure on the wing from moving back and tucking the nose down. This is a separate effect from the drag it may have caused and can't be used to infer the difference in drag. That speed difference was just in controlability at higher speeds. I have a P-38 pilot manual AAF 51-171-1 that doesn't mention drag at all when describing the dive flaps so it likely wasn't significant. It does look like there should be a little drag and maybe a trim change but I haven't seen any figures on it.
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You do realize introducing some measure of drag to the dive flaps would be to the advantage of P-38 pilots right? Anyway, rather surprised they don't induce some drag. You tested this offline?
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Yes I tested it offline. I don't care who it is or isn't an advantage to. Why would you even think in those terms in a bug report thread? :huh
Would you actually prefer a bug to remain in the game if it is to your advantage?
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Yes I tested it offline. I don't care who it is or isn't an advantage to. Why would you even think in those terms in a bug report thread? :huh
Would you actually prefer a bug to remain in the game if it is to your advantage?
No. Just pointing out that deceleration device is quite useful in ACM. It seems odd to me that HTC has overlooked this bit.
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Would you actually prefer a bug to remain in the game if it is to your advantage?
Not exactly unprecedented.
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Unfortunately no...
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No. Just pointing out that deceleration device is quite useful in ACM. It seems odd to me that HTC has overlooked this bit.
I doubt it's overlooked. Looking at parts of aircraft in isolation can be misleading.
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It is physically impossible for it to not produce drag while being in an airflow.
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The dive flaps have a deployed angle similar to the landing flaps of WWII fighters, and they're not that much smaller either, to some of the single-engine fighters. It must produce a lot of drag. If not then we're in flying Unicorn land, magic rainbows and all.
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I have nothing to add to this subject,i just want to stay up to date on it's development.
:noid
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Here's a study of dive brakes and dive flaps. It's just a wing but it looks like a P-38 wing.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20030066111.pdf
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Yeah hitech will fix this in the next millennium.
If all you do is complain trust me the door is that way --->
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Worry about your luft iron leave my 38 alone. Practice in your birds and the 38s wont smoke ya
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Funny. Adding drag to the dive flaps would aid the 38, not make it worse. If HTC changes it, you can thank me later. :aok
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Funny. Adding drag to the dive flaps would aid the 38, not make it worse. If HTC changes it, you can thank me later. :aok
:aok
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FTR, I did a quick test in the P-47M. Offline, 50% fuel, at 500" AGL. The AC actually gained 1 MPH IAS after deploying dive flaps. Something isn't quite right
(http://i207.photobucket.com/albums/bb1/bigsargewells/ahss6-1.png) (http://s207.photobucket.com/user/bigsargewells/media/ahss6-1.png.html)
(http://i207.photobucket.com/albums/bb1/bigsargewells/ahss7-1.png) (http://s207.photobucket.com/user/bigsargewells/media/ahss7-1.png.html)
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Your true air speed didn't change.
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Your true air speed didn't change.
Yes it did. Just not enough to make it 335. There are decimals there, we just don't get to see them.
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Of course. What I meant was that the numbers showing the actual speed didn't change.
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This discussion is silly. True purveyors of twin engine pwnage fly the J or the G. :rock
The only time the L is useful is when you want to chase down 190's and out roll their rolling stick stir. :old:
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Of course. What I meant was that the numbers showing the actual speed didn't change.
And why is that relevant?
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This discussion is silly. True purveyors of twin engine pwnage fly the J or the G. :rock
Nah. Real men fly the one-ten... :aok
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Nah. Real men fly the one-ten... :aok
http://www.youtube.com/watch?v=KMy1zO8m8sM&feature=player_detailpage#t=25
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:lol
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:) :aok
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And why is that relevant?
You're assuming a speed change and neglecting air density.
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You're assuming a speed change and neglecting air density.
This game does not model turbulence or any variations in air density, except with altitude. In level flight if IAS changes, then inevitably so does TAS. If his IAS is 331.4 mph and his TAS is 334.1 the readout will be 331 IAS and 334 TAS. When his IAS increases by 0.2 mph his IAS will be 331.6 and a TAS of 334.3. Since the readout does not show the decimals it will read 332 IAS and 334 TAS.
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IAS will also change if he loses a little altitude. Altitude is not shown in the second screenshot. Which is more likely, increased speed from not adding drag or increased IAS from flying at the altitude where the decimal rounding changes?
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The latter, since he's on auto pilot. And it is not the altitude that changes decimal rounding, but his continued acceleration. His speed had obviously not completely stabilized yet.
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The latter, since he's on auto pilot. And it is not the altitude that changes decimal rounding, but his continued acceleration. His speed had obviously not completely stabilized yet.
So we agree the screen shots don't illustrate any part of this discussion? :D
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No we don't agree. The screenshots show that despite lowering two large flaps into the under-wing airflow the aircraft continued accelerating, even at the very edge of its top speed.
Are you just trolling now?
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We already know the dive flaps don't add drag in subsonic flight in AH. No one claimed that they do.
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Then why carry on this nonsense about the TAS not increasing?
Also please stop calling it "subsonic flight" or "supersonic flight". The P-38 is always subsonic. Localized supersonic airflow does not mean the aircraft is in supersonic flight.
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Then why carry on this nonsense about the TAS not increasing?
I responded to Ammo's post, then you asked me about it. :lol
And yes I do mean airflow.
The question I'd like to see answered is how much drag should the dive flaps add. So far I'm the only one posting test data to support your position.
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According to this article in Aviation News from 1945 the P-47 dive flaps had an extension angle of 21 degrees. In AH it opens to 90 degrees. I hope that will be adjusted along with the P-38L.
http://legendsintheirowntime.com/Content/1945/P47_Av_4502_dive-flap.html
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According to this article in Aviation News from 1945 the P-47 dive flaps had an extension angle of 21 degrees. In AH it opens to 90 degrees. I hope that will be adjusted along with the P-38L.
http://legendsintheirowntime.com/Content/1945/P47_Av_4502_dive-flap.html
There was also an error with the Spitfire flaps until last year. The graphics model was fixed quickly when it was reported. Do not know which angle the flight model was (and indeed is) using.
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One has to wonder... If the dive flaps somehow magically did not create drag, why were they then made retractable? Seems like an unnecessary complication. The stall strips on the F4U were just bolted on the leading edge since they didn't create enough drag to warrant doing something about it.
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One has to wonder... If the dive flaps somehow magically did not create drag, why were they then made retractable? Seems like an unnecessary complication. The stall strips on the F4U were just bolted on the leading edge since they didn't create enough drag to warrant doing something about it.
I really don't think anyone is disputing that the dive recovery flaps created drag, the question is how much drag and how much it effected performance. I realize you found where it said a 59% increase over the wing drag alone….but what does that mean in the big picture for the P-38s performance.
I agree that we should see some effect from deploying the dive flaps in the sense the aircraft should slow…..I just don't know how much it should be effected.
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Then why carry on this nonsense about the TAS not increasing?
Also please stop calling it "subsonic flight" or "supersonic flight". The P-38 is always subsonic. Localized supersonic airflow does not mean the aircraft is in supersonic flight.
Bro you are wasting your time . He is not honest enough to admit you have a point. I argued with him for three years about a bug he liked. He still argues even though it has been fixed. I would like to know how the flaps and aileron boost add no weight. The J is too heavy in game.
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Bro you are wasting your time . He is not honest enough to admit you have a point. I argued with him for three years about a bug he liked. He still argues even though it has been fixed. I would like to know how the flaps and aileron boost add no weight. The J is too heavy in game.
I'm disappointed that you can harass me for years and HTC does nothing about it. If you accused Hitech of dishonesty I doubt you'd still be here.
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I'm disappointed that you can harass me for years and HTC does nothing about it. If you accused Hitech of dishonesty I doubt you'd still be here.
ROFL harass you for years ? :noid :noid
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One has to wonder... If the dive flaps somehow magically did not create drag, why were they then made retractable? Seems like an unnecessary complication. The stall strips on the F4U were just bolted on the leading edge since they didn't create enough drag to warrant doing something about it.
Because they can reduce lift and alter the downwash angle in real life..
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I'm disappointed that you can harass me for years and HTC does nothing about it.
Admitting you were wrong when you are is a marvelous way to immediately stop harassment and not look like a prideful arrogant horse's arse from that point forward.
This thread is now officially retarded. GScholz has clearly found a bug and people are arguing about his methodology and the merit / demerit of correcting it. Welcome to the Aces High forum where one can easily get an argument that black is white. (http://i1114.photobucket.com/albums/k526/rwrk2/facepalm.gif) (http://s1114.photobucket.com/user/rwrk2/media/facepalm.gif.html)
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Admitting you were wrong when you are is a marvelous way to immediately stop harassment and not look like a prideful arrogant horse's arse from that point forward.
This thread is now officially retarded. GScholz has clearly found a bug and people are arguing about his methodology and the merit / demerit of correcting it. Welcome to the Aces High forum where one can easily get an argument that black is white. (http://i1114.photobucket.com/albums/k526/rwrk2/facepalm.gif) (http://s1114.photobucket.com/user/rwrk2/media/facepalm.gif.html)
Speaking of which. Neither one of you noticed that I agree with Gscholz and I posted the data that supports his case?
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Speaking of which. Neither one of you noticed that I agree with Gscholz and I posted the data that supports his case?
That's a separate issue. You did (naturally) take the opportunity to criticize Gscholz's testing method which was entirely irrelevant to his discovery of this bug in the flight model.
Eventually maybe you will notice the consistent element in these unnecessarily awkward exchanges is you.
:salute
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That's a separate issue. You did (naturally) take the opportunity to criticize Gscholz's testing method which was entirely irrelevant to his discovery of this bug in the flight model.
Eventually maybe you will notice the consistent element in these unnecessarily awkward exchanges is you.
:salute
Gscholz didn't test anything that I disagree'd with. What is consistent is you and hlbly failing to appreciate the irony of your criticism.
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Here is more P-47 flight data. Fig.46 is the dive flap acceleration chart. Nothing about dive flap drag.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090022749.pdf
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Here is more P-47 flight data. Fig.46 is the dive flap acceleration chart. Nothing about dive flap drag.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090022749.pdf
Same thing with the flight data from the tests of the use of a dive flap on a XP-51, has the acceleration charts but nothing on drag.
ack-ack
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Plenty of flaps in aces high produce less drag than they should.
What's strange is leading edge slats stopping an airplane almost dead when they deploy.
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Gscholz didn't test anything that I disagree'd with.
You disagreed with his method in order to show how fantastically correct you are which was irrelevant to the discussion.
What is consistent is you and hlbly failing to appreciate the irony of your criticism.
It would have only been ironic if hlbly was incorrect and you were correct. You consistently derail useful and constructive threads with your ego and then whine like a petulant child when criticized for it.
Nice job Gscholz, very good detective work :salute
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You disagreed with his method in order to show how fantastically correct you are which was irrelevant to the discussion.
It would have only been ironic if hlbly was incorrect and you were correct. You consistently derail useful and constructive threads with your ego and then whine like a petulant child when criticized for it.
Nice job Gscholz, very good detective work :salute
You really didn't follow that at all did you? :lol
He said there is no drag. I agree. The question is how much should there be.
You going to add more useful constructive info now?
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Plenty of flaps in aces high produce less drag than they should.
What's strange is leading edge slats stopping an airplane almost dead when they deploy.
I'd enjoying seeing data that supports your ideas.
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You really didn't follow that at all did you? :lol
Well let's see...
So we agree the screen shots don't illustrate any part of this discussion? :D
No we don't agree. The screenshots show that despite lowering two large flaps into the under-wing airflow the aircraft continued accelerating, even at the very edge of its top speed.
Are you just trolling now?
Yeah, the OP has sensed you were positively gushing with agreement and support here.
You going to add more useful constructive info now?
Criticism can also be constructive.
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Nice job Gscholz, very good detective work :salute
:aok
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Yeah, the OP has sensed you were positively gushing with agreement and support here.
Ok nrshida, you continue with the gushing and I'll take the technical questions that you can't handle. :aok
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Ok nrshida, you continue with the gushing and I'll take the technical questions that you can't handle. :aok
I think someone who finds a bug no one has found before deserves a compliment. I think someone who does nothing but look for opportunities to demonstrate how correct they are about nothing particularly special as a platform to talk down to people without making a genuine contribution and even derail technical threads to do this should be criticized. :aok
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I'd enjoying seeing data that supports your ideas.
How about you simply try it out yourself rather than sit there like a baby bird squawking away with beak upturned so you can be spoon fed the data you argue.
Try a little experimentation.
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How about you simply try it out yourself rather than sit there like a baby bird squawking away with beak upturned so you can be spoon fed the data you argue.
Try a little experimentation.
I tried the flaps. Now please explain how they have less drag then they should.
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I think someone who does nothing but look for opportunities to demonstrate how correct they are about nothing particularly special as a platform to talk down to people without making a genuine contribution and even derail technical threads to do this should be criticized. :aok
You still don't realize you're describing your current behavior here?
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You still don't realize you're describing your current behavior here?
The only point I am asserting I am right about (which was in response to you once again unjustifiably starting on hlbly) is that you troll as much as the next man, just with more subtle packaging. Trying to take the moral high ground afterwards and implying you get trolled by people of lesser intellect while only making contributions is simply your method to wriggle out of criticism for it (to which you seem particularly sensitive to).
Ok nrshida, you continue with the gushing and I'll take the technical questions that you can't handle. :aok
Let's review your technical contribution to this thread:-
I don't know what it adds to the drag coefficient.
I have a P-38 pilot manual AAF 51-171-1 that doesn't mention drag at all...
I doubt it's overlooked.
<snip>
Start of irrelevant nonsense about the TAS not increasing (even though you later claim you agree with the point you are arguing with).
So we agree the screen shots don't illustrate any part of this discussion? :D
Are you just trolling now?
(I include this last quote to prevent implications on your part that I'm the only one that thinks you troll).
Then you upload some P-47 flight data which you say states nothing about dive flap drag.
So actually FLS, you've taken precisely NO technical questions that I or anyone else can't handle, contributed nothing technical at all and done nothing but muddy the waters on this issue and harass the OP with irrelevancies and pointless criticism.
Like I say, continuing to use 'begging the question', 'escape hatch', 'moving the goalposts' and your other favourite logical fallacies in this and other threads makes you a hypocrite, and just as much a troll / griefer as if someone were to imply that someone else were an arrogant, egotistical, narcissistic horse's arse with Asperger's, who'd rather derail a thread than be seen to be wrong. Ever, for instance.
I actually find your technical contributions rather simplistic, bookish, unimaginative and yet condescending all at the same time, which is why I hold my present opinion of you.
If you were as technically fantastic as you think you are, genuinely more intelligent than the rest of us, and your only purpose was to make positive contributions (which I think is dishonest of you at best) in an environment of stupid people then why don't you produce equations to calculate the drag of the P-38 dive recovery devices?
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The only data sources posted in this thread that support Gscholz are from me.
Here's a study of dive brakes and dive flaps. It's just a wing but it looks like a P-38 wing.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20030066111.pdf
Here is more P-47 flight data. Fig.46 is the dive flap acceleration chart. Nothing about dive flap drag.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090022749.pdf
The point about IAS is a simple one. Gscholz pointed out that decimals may be rounded up. The same is true when considering air pressure as with speed. How much do you need to descend to change 119 mph IAS to 120 mph with a fixed TAS? If you only need to change 119.49 to 119.50 then it likely isn't very much. If there is an altitude where xxx.49 changes to xxx.50 then there is an altitude a few feet above that which you may be starting from. In any event it says nothing about the dive flaps so the screen shots do nothing to "illustrate" (get it?) the discussion.
You and hlbly have both made the same contribution to this thread. You both made personal attacks for no reason other than spite. Now I'm thinking you don't know what irony is. :lol
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You assume the P-47's altitude changed in the two screen shots? I assure that it did not. I was on autopilot and mil power. The AC's speed was stable before I deployed the dive flaps and actually increased, albeit slightly after they were deployed.
The screen shots I posted do support Gscholz's observation that there is something wrong with how dive flaps are modeled in AH.
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P-38 flight manual page #34 of Scribd link & page #30 of manual.
http://www.scribd.com/doc/147641300/1945-Pilot-s-Flight-Operating-Instructions-for-Army-Models-P-38H-Series-P-38J-Series-P-38L-1-L-5-and-F-5B-Airplanes
http://www.kazoku.org/xp-38n/articles/p38info.htm
Not sure if it helps with this discussion?
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There is no information that has been posted that documents dive flap drag in subsonic flow. The drag from Mach drag from the top wing and mach drag at the dive flap is not documented in this thread.
My WAG is the paint and unpainted issue of drag and weight over shadow any small drag from a subsonic deployment of the dive flap.
Another interesting point was it is thought the thick airfoil selection by Lockheed was the root cause of the problem. Later on, raising the tail to a higher position on future designs was a better way to deal with the problems in transonic flow.
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I think Cactus's post in the other P-38 thread made it clear that there is some drag even at low speeds and it limits your top speed. Is it a bug or a wishlist item? I expect there's a good reason it's not already modeled, along with a trim change, even if it turns out it should be.
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Seems like if it was anything but a bug someone at HTC would have been along by now.
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You and hlbly have both made the same contribution to this thread. You both made personal attacks for no reason other than spite. Now I'm thinking you don't know what irony is. :lol
Not personal it's a criticism of your methods. Why would we need to be spiteful? You were the one who was wrong.
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Nah. Real men fly the one-ten... :aok
I knew there was a reason I liked you. :D :aok
FYI - I like you too, Triton. I simply choose to overlook your love for the B-38. ;)
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I think Cactus's post in the other P-38 thread made it clear that there is some drag even at low speeds and it limits your top speed. Is it a bug or a wishlist item? I expect there's a good reason it's not already modeled, along with a trim change, even if it turns out it should be.
Sure some drag but small below transonic speed. How small? We don't know. And the OP assumes you deploy the flap and continue on without diving which would be pilot error. What the OP should ask is Mach drag in the model? A much larger issue.
Again keep in mind the dive flap will only produce appreciable lift if the top wing breaks continuous laminar flow. Then the flap is deployed breaks breaks laminar flow on the bottom of the wing to counter. Another way to put it is, without the dive flap, the bottom of the wing has more negative lift than the top wing has positive lift in transonic flow.
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Not personal it's a criticism of your methods. Why would we need to be spiteful? You were the one who was wrong.
In a world constantly changing wouldn't it be nice for just once . The bad things change and the good stay the same? I never could state it as eloquent as you my friend.
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And the OP assumes you deploy the flap and continue on without diving which would be pilot error.
No he didn't. He pointed out that the dive recovery flap doesn't seem to have any drag modeled and he is certainly correct that there should be some degree of speed decrease if the flap is extended.
I don't feel that having the drag modeled will make a huge increase in game, the only folks who will notice it will be the ones who forget to retract it and lose some speed when level.
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As it is now you can just extend the flap before rolling and leave it out, never bother with it. If that was HTC's intention when adding the dive flaps then why did they make it a manually operated item in the game? Seems to me they intended for it to be used only when needed like it was in real life, but for some reason the drag and other consequences for having them deployed below Mach .68 was not modeled.
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As it is now you can just extend the flap before rolling and leave it out, never bother with it. If that was HTC's intention when adding the dive flaps then why did they make it a manually operated item in the game? Seems to me they intended for it to be used only when needed like it was in real life, but for some reason the drag and other consequences for having them deployed below Mach .68 was not modeled.
I do see your and Columbo's point. But, maybe it is modeled but not enough measurable difference in the game as GScholz points out in his reply that the dive flap is left on all of the time(The pilot error I was referring to).
Again actuation in the subsonic region is a mute point as there is no document that shows the change in drag coefficient with the flaps down that I have seen. We can only guess it will change but the antidote information out there suggest sub transonic region there is no notable lift. Also note that if a notable speed reduction occurred, then i think we would have found antidote type evidence at least in place of hard numbers.
My WAG again is the P-38L is modeled with the best hard-fact information available to the coder. If someone has additional hard facts then let them come forward.
What this thread did do was advance our knowledge of why the dive flap was designed the way it is. My :salute to GScholz for that.
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My WAG again is the P-38L is modeled with the best hard-fact information available to the coder.
I think it is more likely an oversight as an unfortunate side effect of flight modeling and graphical modeling being separate.
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I think someone who finds a bug no one has found before deserves a compliment. I think someone who does nothing but look for opportunities to demonstrate how correct they are about nothing particularly special as a platform to talk down to people without making a genuine contribution and even derail technical threads to do this should be criticized. :aok
:aok
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Not personal it's a criticism of your methods. Why would we need to be spiteful? You were the one who was wrong.
You didn't post anything showing I was wrong. You just keep saying it. You're not criticizing my methods you're criticizing my opinions. You don't agree, you obviously can't argue subjects you don't begin to understand, and you can't handle that gracefully.
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You didn't post anything showing I was wrong. You just keep saying it. You're not criticizing my methods you're criticizing my opinions. You don't agree, you obviously can't argue subjects you don't begin to understand, and you can't handle that gracefully.
Ah good, an opportunity to demonstrate I do understand irony: you're still butt-hurt from being shown to be wrong about a year ago and you're implying it's the other parties that can't handle things gracefully. Now that's irony! :lol
I don't agree with your opinion that the drag was not overlooked because I suspect intuitively it will be more than the trivial amount you're implying it is, but actually in this case I'm more criticising your argumentative and irrelevantly pedantic approach (which incidentally derails threads) just to try and make yourself look superior.
For instance this is now something like the fifth opportunity you've taken to imply I am unable to understand the subject because I'm not as intelligent as you. Despite your continual implication that you think you've made only positive contributions to this topic I've still seen no original effort on your part to actually quantify the drag.
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Ah good, an opportunity to demonstrate I do understand irony: you're still butt-hurt from being shown to be wrong about a year ago and you're implying it's the other parties that can't handle things gracefully. Now that's irony! :lol
I don't agree with your opinion that the drag was not overlooked because I suspect intuitively it will be more than the trivial amount you're implying it is, but actually in this case I'm more criticising your argumentative and irrelevantly pedantic approach (which incidentally derails threads) just to try and make yourself look superior.
For instance this is now something like the fifth opportunity you've taken to imply I am unable to understand the subject because I'm not as intelligent as you. Despite your continual implication that you think you've made only positive contributions to this topic I've still seen no original effort on your part to actually quantify the drag.
You are referring to the haptic thread where hlbly admitted that the tests he did, on the AH version prior to the FFB update, did in fact prove that everything I claimed about it was correct. Then, not having gotten the results he expected, he claimed that the version he had tested was some other version and not the one he meant to test. This after he had posted pics showing that it was in fact the version in question. Then you both stopped posting in the thread. I wasn't hurt by that. I still laugh about it. It's an epic fail.
Let us see anyone quantify the drag from the dive flaps. Since we lack the required test information it should be interesting. I'm sure tests were done and HTC may have a copy but we don't. The UK Air Ministry in 1953, after reviewing all the data on dive flaps available to them, concluded that it was impossible to predict the effect of dive flaps throughout the flight regime because there were too many variables interacting, only flight testing can give conclusive results. So far we have information that there was drag and there was a pitch up when deployed after compression. The first time I saw this discussed here was Feb 2002. I think HTC is aware of all the issues, including drag.
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(https://dl.dropboxusercontent.com/u/26232318/jumpwindow.gif)
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I smell a dead horse.
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You are referring to the haptic thread...
No, I'm eluding to the part where you asserted there was nothing wrong with Haptic Feedback as it was modeled (as it turned out, because you preferred it that way) hlbly demonstrated through independent research and consultation with an expert that it was incorrect, HTC corrected it, and then at a later date you used every logical fallacy and argumentative trap you could think of to try to humiliate him and save face.
Don't think you can re-image those sequence of events, troll boy.
Let us see anyone quantify the drag from the dive flaps. Since we lack the required test information it should be interesting. I'm sure tests were done and HTC may have a copy but we don't. The UK Air Ministry in 1953, after reviewing all the data on dive flaps available to them, concluded that it was impossible to predict the effect of dive flaps throughout the flight regime because there were too many variables interacting, only flight testing can give conclusive results. So far we have information that there was drag and there was a pitch up when deployed after compression. The first time I saw this discussed here was Feb 2002. I think HTC is aware of all the issues, including drag.
Zomg, now you really have gone full retard. You have absolutely no imagination or insight whatsoever do you. So no drag should be modeled because its behaviour could not be predicted without real world flight testing of an actual P-38 in every flight regime?
As accurate as HTC's flight simulation is it is still a model, an approximation, a representation. Do you really think they haven't been forced to use reasonable, educated assumptions and approximate calculations in other areas of flight modeling given the absence of actual specific flight test data?
This is absolutely no criticism of HTC by the way, if you're listening. I think their work is fantastic given the mostly non-flying antiques they are modeling, but are you really suggesting that the drag could not be reasonably calculated through an abstract model of some kind?
Congratulations FLS you win. Another excellent, reasonably investigated and presented issue discovered by a player of this game destroyed by your pedantic monkey business. Of course you have rather demonstrated what you're all about in order to do it haven't you? Good luck with the repairs to your future credibility.
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(https://dl.dropboxusercontent.com/u/26232318/jumpwindow.gif)
:rofl :rofl How appropriate :salute
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(https://dl.dropboxusercontent.com/u/26232318/jumpwindow.gif)
:lol
thats pretty good
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No, I'm eluding to the part where you asserted there was nothing wrong with Haptic Feedback as it was modeled (as it turned out, because you preferred it that way) hlbly demonstrated through independent research and consultation with an expert that it was incorrect, HTC corrected it, and then at a later date you used every logical fallacy and argumentative trap you could think of to try to humiliate him and save face.
Don't think you can re-image those sequence of events, troll boy.
Zomg, now you really have gone full retard. You have absolutely no imagination or insight whatsoever do you. So no drag should be modeled because its behaviour could not be predicted without real world flight testing of an actual P-38 in every flight regime?
As accurate as HTC's flight simulation is it is still a model, an approximation, a representation. Do you really think they haven't been forced to use reasonable, educated assumptions and approximate calculations in other areas of flight modeling given the absence of actual specific flight test data?
This is absolutely no criticism of HTC by the way, if you're listening. I think their work is fantastic given the mostly non-flying antiques they are modeling, but are you really suggesting that the drag could not be reasonably calculated through an abstract model of some kind?
Congratulations FLS you win. Another excellent, reasonably investigated and presented issue discovered by a player of this game destroyed by your pedantic monkey business. Of course you have rather demonstrated what you're all about in order to do it haven't you? Good luck with the repairs to your future credibility.
It's amazing how much power I have. Every wish and bug report is at my mercy. :lol
That was a quote from those "retards" in the Air Ministry. They had a bunch of older P-38s. Capt Eric Brown wrote about flying a borrowed F-5E specifically to test the dive flaps and aileron boosters. And their conclusion, looking at all the data available in 1953, was that modeling dive flaps was too complicated to get accurate results. Maybe Hitech will share some insight with us about the P-38 and P-47 dive flap model since they use essentially the same dive flap and neither one has a drag penalty or a pitch up.
I have clearly stated that I believe there should be a pitch up and some drag. Somehow in your mind that puts me in opposition to the OP. You have been consistently wrong about everything. In the haptic thread you mentioned you also never got anything right. That's a large part of why I ignored everything you wrote. That and the rudeness. I won't rehash it here but anyone can read it and decide for themselves. Anyone with FFB can test an old version themselves. All the proof is available for anyone with the interest. No discussion neccesary. :D
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(http://upload.wikimedia.org/wikipedia/en/e/e0/Energizer_Bunny.png)
It's amazing how much power I have. Every wish and bug report is at my mercy. :lol
People would just rather go do something else than bother discussing with you. About as much point as talking to the wall.
looking at all the data available in 1953, was that modeling dive flaps was too complicated to get accurate results.
It's no longer 1953.
I have clearly stated that I believe there should be a pitch up and some drag. Somehow in your mind that puts me in opposition to the OP.
Completely missing the point I've been banging on about for about 3 pages. Willfully I should expect.
You have been consistently wrong about everything.
Yeah I've got rotten luck too. You'd think I'd get something right completely by chance. :lol
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Maybe Hitech will share some insight with us about the P-38 and P-47 dive flap model since they use essentially the same dive flap and neither one has a drag penalty or a pitch up.
Don't know about the dive flaps on the P-47 in game but on the P-38L, the dive flaps do provide a nose up pitch. This was tested by both Widewing and myself a couple of years ago and posted our results.
ack-ack
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It's amazing how much power I have. Every wish and bug report is at my mercy. :lol
. . . Maybe Hitech will share some insight with us about the P-38 and P-47 dive flap model since they use essentially the same dive flap and neither one has a drag penalty or a pitch up. . .
You need to qualify the speed here. In a dive, extra drag maybe modeled. We have no way of testing. Any flat level drag due to flaps may be modeled in but the change is so small, it is undetectable. From all I have read, I see zero evidence the model is wrong or right.
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Don't know about the dive flaps on the P-47 in game but on the P-38L, the dive flaps do provide a nose up pitch. This was tested by both Widewing and myself a couple of years ago and posted our results.
ack-ack
When I dive I find that the nose goes according to the trim setting. I can dive straight in to the ground or dive and pull out from pre-setting the trim. I don't find a difference between opening the dive flaps before I dive or after I'm buffeting. Opening after the buffet is supposed to pitch up enough to loop, 3-4g just from the dive flaps. I don't doubt your results Ack-Ack but I don't recall the post and I don't know if we're looking for the same degree of pitch change. Link?
You need to qualify the speed here. In a dive, extra drag maybe modeled. We have no way of testing. Any flat level drag due to flaps may be modeled in but the change is so small, it is undetectable. From all I have read, I see zero evidence the model is wrong or right.
The info Cactus posted was advice to pilots. It's really hard to believe that they would be warned about a negligble amount of drag that is undetectable. It would be easier to believe that the extra drag was only prior to compression and it was reduced at compression because of the difference in the center of pressure but that's just spit balling. It seems likely that if all we needed was a fixed increase in the coefficient of drag from the dive flaps we'd have that already.
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Something I noticed in Ammo's pix is the fact that after the flaps were lowered the climb rate changed,now to be fair it was a small change from 1 fpm to 0 fpm but that does indicate a change in AoA so the flaps seem to be doing something.
Of course that could be just bullpucky and the change is the reason the airspeed increased.
:salute
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If you look at the map he's changed position noticably and we don't see the altitude on the 2nd shot.
I think the best thing to take away from ammo's pic is that the P-47 dive flap visual model is also extended 90 degrees instead of 21 degrees for the P-47. The amount of drag and pitch up should be clear to anyone testing it. I don't notice any.
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Any one care to take the plunge & purchase this?
http://discovery.nationalarchives.gov.uk/SearchUI/Details?uri=C4020638
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We already have a few sources indicating a 3-4g pitch up when deployed at high speeds. Dive flap drag tests on the actual aircraft would be nice if we can find them. Since the intention was always to close the dive flaps as soon as they aren't needed it may be that drag tests for normal flight weren't considered important.
At least the dive flaps we have work properly when we need them to. If you open them before the dive and close them as soon as they aren't needed you should have a well modeled "realistic" dive.
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Well the results might be in here 50 pages of Naca testing for a total of 16,457 documents . I won't be going through them all to find the one on the P-38. The first document alone is enough to make your head swim.
http://www.scribd.com/search-documents?escape=false&page=1&query=NACA+Ames+Aeronautical+Laboratory+Records+
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The P-47 uses essentially the same dive flap. Either one would be good. Flight testing for dive flap drag in service aircraft would be ideal. :D
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The P-47 uses essentially the same dive flap. Either one would be good. Flight testing for dive flap drag in service aircraft would be ideal. :D
P-51 do?
Don't have time to read it have to go to work.
http://www.scribd.com/doc/139117583/34811307-NACA-P-51X-Dive-Flap-Mods
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That was the same dive flap mounted for testing on a P-51. There should be a free version of that document somewhere.
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That was the same dive flap mounted for testing on a P-51. There should be a free version of that document somewhere.
This is the link for the report on the dive flap testing on a XP-51.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930093004_1993093004.pdf
ack-ack
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Thanks Ack-Ack. Still no drag or speed differences. They do state that the deployed flap pitch up is independent of the pitch trim with the flaps closed.
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Here is a quote from gripen where he posts some drag numbers from a wind tunnel test. Unfortunately, the links he provided are no longer valid but he does mention the serial number of the report with the drag data.
Ack-Ack and Murdr,
It would help a lot if you actually understand what the report (http://http://naca.larc.nasa.gov/reports/1947/naca-rm-a7c24/) says:
"The outboard dive recovery flaps produced favorable shift in trim by decreasing the angle of attack for the zero lift and increasing downwash on the tail, but did not alter the the mach number the diving tendency developed"
Note the part on angle of attack (Ack-Ack) and part on diving tendency (Murdr), this can be confirmed from the graphs (http://naca.larc.nasa.gov/reports/1947/naca-rm-a7c24/index.cgi?page0023.gif) too.
For wind tunnel data on drag you should get that DSIR 23/15088. Here is some numbers from that report:
mach clean flaps
0,5 0,030 0,034
0,6 0,035 0,05
0,65 0,042 0,10
At mach 0,65 the dive recovery flaps doubled the drag.
gripen
ack-ack
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I assume that's wing drag not total drag so the increase in total drag at .5 Mach would be less than 13 % ? In either case it seems drag should be noticeable. I'm guessing the lack of difference in top speed is due to the shock wave drag being so high.
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Well. Since aviation scientists in 1953 could not accurately predict the effect of dive-flaps on a plane, and there's no reliable information on how they handled, and since HiTech refuses to make a phony mock-up of the dive-flap system...
I vote that HiTech simply remove the P-38L from the game.
A wise man once told me, "Be careful what you wish for."
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Well. Since aviation scientists in 1953 could not accurately predict the effect of dive-flaps on a plane, and there's no reliable information on how they handled, and since HiTech refuses to make a phony mock-up of the dive-flap system...
I vote that HiTech simply remove the P-38L from the game.
A wise man once told me, "Be careful what you wish for."
You may want to try reading a little slower. :aok
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That was the same dive flap mounted for testing on a P-51. There should be a free version of that document somewhere.
The link I posted before & the one AKAK has posted are one the same.
Scribd is free.
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Scribd asks for payment to DL the doc.
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Scribd asks for payment to DL the doc.
Really :headscratch: why can I access all that for nothing then?
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You may want to try reading a little slower. :aok
Meh I skim over these topics, and rarely ever go passed the second page. I just find that all topics seem to degrade into useless slander after that.
I really just wanted to say, "Be careful what you wish for"
...And slightly mad that the 109G10 was replaced with the less potent 109G14...
If I can't have my smoothed out engine cowl and an extra ~200HP, you can't have your P-38Ls. Settle with the J.
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Meh I skim over these topics, and rarely ever go passed the second page...
Good to know. Thanks for clearing that up.
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Well Gscholz, thanks for identifying the issue. Good observation. Sorry the thread was derailed into something more and unneeded.
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Well. Since aviation scientists in 1953 could not accurately predict the effect of dive-flaps on a plane, and there's no reliable information on how they handled, and since HiTech refuses to make a phony mock-up of the dive-flap system...
I vote that HiTech simply remove the P-38L from the game.
A wise man once told me, "Be careful what you wish for."
Guys, no one, I repeat no one, has presented any information that proves the HTC model is wrong.
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Well Gscholz, thanks for identifying the issue. Good observation. Sorry the thread was derailed into something more and unneeded.
Can't expect anything else on this BBS ;)
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Guys, no one, I repeat no one, has presented any information that proves the HTC model is wrong.
Except that it defies the laws of physics. It is quite impossible for the dive flaps to not produce drag, at any air speed.
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Except that it defies the laws of physics. It is quite impossible for the dive flaps to not produce drag, at any air speed.
Is it no drag or is it so small, it can't be measured in the game? You assume the drag is sufficient to be detectable. Maybe it is not.
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It is impossible to fly at 300+ mph and put something like that into the under-wing airflow and not have it slow the plane down noticeably. Even a single empty weapons pylon slows a WWII fighter down by several mph. The Fw 190A-5 for example loses 9 mph of its SL top speed by carrying an empty centerline bomb pylon.
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It is impossible to fly at 300+ mph and put something like that into the under-wing airflow and not have it slow the plane down noticeably. Even a single empty weapons pylon slows a WWII fighter down by several mph. The Fw 190A-5 for example loses 9 mph of its SL top speed by carrying an empty centerline bomb pylon.
It would seem that way but we have nothing as fact or antidote to support your claim.
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You consider the fact that the P-38 pilot's handbook says they produce "some drag" to be, what... "nothing"?
If there is insufficient data to model them accurately they shouldn't have been added in the first place.
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You consider the fact that the P-38 pilot's handbook says they produce "some drag" to be, what... "nothing"?
If there is insufficient data to model them accurately they shouldn't have been added in the first place.
I do think if the number was significant, a stronger warning would have been made. Again it would against operating procedure to leave them on all of the time or pilot error.
Do you know HTC doesn't have the data?
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If they didn't produce significant amounts of drag, they wouldn't have been retractable. Like the stall strips on the F4U they would have been just bolted on.
It is difficult to know what data HTC has since they so far have chosen not to comment on the issue.
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If they didn't produce significant amounts of drag, they wouldn't have been retractable. Like the stall strips on the F4U they would have been just bolted on.
It is difficult to know what data HTC has since they so far have chosen not to comment on the issue.
Still you have no facts just assumptions guesses. Keep in mind I also have zero facts to say the model is right.
Do more digging. You might just find the facts that say you are right.
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They defy the laws of physics. That's proof enough of a bug to report it. If you choose to believe in magic then that's your prerogative. If HTC choose to do nothing about it that's their prerogative. My job is done. Good night. :)
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Still you have no facts just assumptions guesses. Keep in mind I also have zero facts to say the model is right.
Do more digging. You might just find the facts that say you are right.
Randy the descriptions and tests we're reading do not seem to match the game performance. Gscholz is correct, there is no noticeable drag and we have no explanation of why.
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Randy the descriptions and tests we're reading do not seem to match the game performance. Gscholz is correct, there is no noticeable drag and we have no explanation of why.
He may very well be right. I think we just need some old test data to offer to HTC .
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Guys, no one, I repeat no one, has presented any information that proves the HTC model is wrong.
Randy you don't need to have something in writing to know something is amiss. Common sense says the dive flap would produce some drag, that drag is going to slow the airplane…really no ifs, ands or buts about that. The big unknown is "how much".
There are some speed brakes used on Mooney aircraft, small tabs that protrude from the wing skin when open. At high speeds such as in a descent they are very effective, at lower speeds (such as approach to landing) they don't produce as much drag and have little effect on performance. (It's a physics thing, double the speed quadruple the drag IIRC) IMO that is what we should be seeing from the dive recovery flaps on the aircraft in game.
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If they didn't produce significant amounts of drag, they wouldn't have been retractable. Like the stall strips on the F4U they would have been just bolted on.
You can't say that for sure. They do produce a pitching moment which might be undesirable at times, other factors to consider regarding retraction other than just drag.
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If I remember right drag is relates to the square of the velocity in the subsonic range or laminar range.
I keep thinking that the dive flap,s noticeable drag occurs when the boundary layer breaks. The design suggests to me, they wanted the boundary layer to only break at the same speed the top wing damned up.
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Meh I skim over these topics, and rarely ever go passed the second page. I just find that all topics seem to degrade into useless slander after that.
I really just wanted to say, "Be careful what you wish for"
...And slightly mad that the 109G10 was replaced with the less potent 109G14...
If I can't have my smoothed out engine cowl and an extra ~200HP, you can't have your P-38Ls. Settle with the J.
Not to hijack this thread but we never had a G10 we had a K4 that was labled as a G10 so it could use the optional weapons,it had the performance of the K4. So we got the K4 and the G14 in exchange for the socalled G10.
I miss the old G10 too but I glad HTC fixed that issue.
Getting back to the P38L, IIRC widewing tested the dive flap and he found that you need to turn off combat trim and use manual trim to see the effects of the dive recovery flaps. I'm not sure of the difference as I havent flown the 38,let alone the 38L in quite a long time.
:salute
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Is it no drag or is it so small, it can't be measured in the game? You assume the drag is sufficient to be detectable. Maybe it is not.
Doesn't seem to be all that small according to the chart posted by gripen 10 years ago. Totally forgot that we had this discussion back then until I found the thread again.
ack-ack
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Randy you don't need to have something in writing to know something is amiss. Common sense says the dive flap would produce some drag, that drag is going to slow the airplane…really no ifs, ands or buts about that. The big unknown is "how much".
This is what I have found particularly exasperating about this thread. We can infer how much. Anyone with an intuitive understanding of aerodynamics (including you colmbo, apparently) would reasonably agree that a 45 degree deflection of airflow followed by another 90 degree change in close proximity at the apex over such an extensive span is going to produce an awful lot more separated turbulent air than the streamlined bomb / drop tank pylons of the Mosquito, for example (other less significant causes of drag notwithstanding).
The drag might indeed be mitigated in the presence of localized supersonic flow or a pitch change of the wing in a very steep high speed dive (I can imagine very strange things happening there) but even if that was the case the drag would still anounce at lower and indeed cruise speeds where the flow is completely subsonic.
Since the Mosquito's extra drag is observable, the absence of any extra drag with the P-38L dive flaps deployed is clearly an omission, most likely by oversight (although there are at least two other possibilities).
Campaigning that the drag is negligible (with no evidence) or that no change should be made without exact data (also therefore no evidence) surely results in less realism by having absolutely no drag at all?
Or is my logic terribly flawed? Obviously I have to ask because I have a complex now about being wrong all of the time :lol
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Your logic is perfectly sound. :aok
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Doesn't seem to be all that small according to the chart posted by gripen 10 years ago. Totally forgot that we had this discussion back then until I found the thread again.
ack-ack
That chart still around?
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An interesting point on the dive flap instructions that Cactus posted is the assurance that if only one dive flap deploys you wont even notice it at low speeds. It will only roll you at high speeds and can be countered with aileron. That does not sound like there would be a pitch moment at low speeds when both deploy.
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That chart still around?
The link I quoted from gripen's original post is no longer valid but the link does contain the NACA report name that had the graph/chart he quoted.
ack-ack
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Perhaps I misunderstand, but I can't find a link in your previous post...
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Perhaps I misunderstand, but I can't find a link in your previous post...
Sorry, the hyperlink in gripen's post I quoted was kind of hard to spot. This was the link, you'll get a server access denied error message.
http://naca.larc.nasa.gov/reports/1947/naca-rm-a7c24/index.cgi?page0023.gif
ack-ack
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Here's a copy Gscholz.
http://digital.library.unt.edu/ark:/67531/metadc58047/m1/1/
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So what am I looking at? Page 23? I can't identify anything drag related there, but then I'm no expert all this...
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Here's two references used for Ack-Ack's report.
http://www.dtic.mil/dtic/tr/fulltext/u2/a801389.pdf
http://digital.library.unt.edu/ark:/67531/metadc61223/m1/1/
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According to that the drag coefficient is significantly increased.
I've reported this bug. Now it is up to HTC if they want to do something about it.
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According to that the drag coefficient is significantly increased.
I've reported this bug. Now it is up to HTC if they want to do something about it.
Which page or pages did you find that information?
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Second link figure 15 at page 24 shows the increase in drag coefficient at various speeds and flap angles. Consider that the P-38's zero-lift drag coefficient is 0.0268, those flaps add a lot of drag. Even the lowest figures at 35 degrees flap angle approximately doubles the P-38's drag at Mach .5 (~370 mph at SL).