Aces High Bulletin Board
Help and Support Forums => Help and Training => Topic started by: flatiron1 on December 21, 2016, 01:48:35 PM
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when I use the toe brakes on my rudder pedals I stop quickly and see a nose dip. If I use the keyboard nothing happens. Does the rudder pedal function cancel out the keyboard function?
whoops wrong forum
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when I use the toe brakes on my rudder pedals I stop quickly and see a nose dip. If I use the keyboard nothing happens. Does the rudder pedal function cancel out the keyboard function?
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Pretty sure putting any control that can use it on an axis cancels out the button for the same function. Among others like brakes, things like zoom, rudder, etc.
Wiley.
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It should not cancel out the keypad. The difference is that with toe brakes you can adjust how much braking you want or need. You can also use braking to offset drag from damage making you go off the runway.
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Make sure you have the analog brake functions mapped, and not the on/off function like what is default for the keyboard.
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Pretty sure putting any control that can use it on an axis cancels out the button for the same function. Among others like brakes, things like zoom, rudder, etc.
Wiley.
Pretty sure assigned analog inputs live happily with assigned digital inputs, as long as they are not mapped to the same device at the same time.
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Pretty sure assigned analog inputs live happily with assigned digital inputs, as long as they are not mapped to the same device at the same time.
If that's true, why would it matter if it was on the same device?
Either you move an analog input, or pressing a digital button. Do them both at the same time you may have issues, regardless of which
device they're mapped to.
Coogan
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strange, I can use keyboard or joystick to adjust rpm but brakes only work with one or the other.
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when I use the toe brakes on my rudder pedals I stop quickly and see a nose dip. If I use the keyboard nothing happens. Does the rudder pedal function cancel out the keyboard function?
Yes, if you have toe brakes assigned to your rudder pedals it will over-ride the keybinding for wheel brakes.
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Flatiron, the Rudder Toe brakes should be an analog setting, so you can adjust the dead band and damping to keep the nose over from being so abrupt. You can also adjust the scaling to help even more. :rock
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strange, I can use keyboard or joystick to adjust rpm but brakes only work with one or the other.
Interesting. I'm pretty sure putting zoom on an axis overrides the zoom buttons, which is what I was thinking of at the time.
Wiley.
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ok what I want to do is be able to use my rudder pedals for left/right braking and also have a function where I can apply both brakes equally at the same time. there is a button setting for the controls that says flight wheel brakes but does not seem to work.
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Are you mapping analog control, like for your ailerons rudder and throttle, or the button function like for views and fire button?
My right toe brake wire broke, so I use my left toe brake to apply brakes to both right and left wheels. Works fine for my setup, but I really miss differential braking for getting onto the rearm pad.
Edit:
After reading again, it sounds like you're using the pedals for brakes instead of for rudder, and don't have actual toe brake movement? What kind of pedals do you have?
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I use pedals for rudder and toe brakes. Ch pedals .
I just want to be able to have a function that will work both brakes simultaneously like yo would be able to do if using keyboard onlyit
What is the control function named flight brakes suppossed to do?
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Flat,
Set the toe brakes to work as a push button,IIRC there is a analog setting to do that,dont have access to my game machine to verify. Basically set the toe brakes to "C" and "V" then you should be able to set a button for brakes and have what you want.
I use a hatswitch for differential brakes and a button to brake since my pedal toe brakes quit.
You cant have analog toe brakes and a brake button/switch/lever unless you map the analog as a button press.
:salute
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I use pedals for rudder and toe brakes. Ch pedals .
I just want to be able to have a function that will work both brakes simultaneously like yo would be able to do if using keyboard onlyit
What is the control function named flight brakes suppossed to do?
You'll have to press on both pedals to do what you want. When I was using CH Pro Pedals, I had no troubles using both toe brakes (left/right) simultaneously for braking.
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I use pedals for rudder and toe brakes. Ch pedals .
I just want to be able to have a function that will work both brakes simultaneously like yo would be able to do if using keyboard onlyit
What is the control function named flight brakes suppossed to do?
Even though this does not answer your question you might try using the "Advanced" setting for the pedals to make them more user friendly so you do not need a button to apply both brakes at the same time like the space-bar does on the keyboard.
Flight brakes? I will have to look that one up.
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Flight brakes is probably referring to dive brakes air brakes, like the P38-L has....I would assume
TC
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there is a separate one for dive brakes.
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there is a separate one for dive brakes.
Heh, that is what one gets for assuming...I have to admit it probably has been 6+ years since I last fully went and looked through the whole list of key mapping...
TC
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You don't have toe brakes on your rudder pedals?
ok what I want to do is be able to use my rudder pedals for left/right braking and also have a function where I can apply both brakes equally at the same time. there is a button setting for the controls that says flight wheel brakes but does not seem to work.
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lol read the first post.
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I use pedals for rudder and toe brakes. Ch pedals .
I just want to be able to have a function that will work both brakes simultaneously like yo would be able to do if using keyboard onlyit
What is the control function named flight brakes suppossed to do?
default brake in AH is the space bar, not the rudder keys. I use the CH pedals, for rudder and the space bar for brake.
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Both P-47 and P38L have "dive recovery flaps" in real life.
In the game, there is a dive recovery flaps yellow light which allows you "dive a little faster"..... turn it on when you take the runway as it has zero drag, zero effect except for allowing you to go just a little faster.
In Real life, it was a hydraulic flap which actuated into the slipstream moving the center of lift to regain aircraft control (while also slowing the aircraft some). Better explained here:
"The P-38's dive problem was revealed to be the center of pressure moving back toward the tail when in high-speed airflow. The solution was to change the geometry of the wing's lower surface when diving in order to keep lift within bounds of the top of the wing. In February 1943, quick-acting dive flaps were tried and proven by Lockheed test pilots. The dive flaps were installed outboard of the engine nacelles, and in action they extended downward 35° in 1.5 seconds. The flaps did not act as a speed brake; they affected the pressure distribution in a way that retained the wing's lift."
-Bodie, Warren M. The Lockheed P-38 Lightning: The Definitive Story of Lockheed's P-38 Fighter. Hayesville, North Carolina: Widewing Publications, 2001, 1991. ISBN 0-9629359-5-6.
(http://history.nasa.gov/SP-440/p28a.jpg)
(http://migrate.legendsintheirowntime.com/LiTOT/Content/1944/P38_Av_4408_DA_flap_p127_W.png)
They worked so well, they were equipped on the mighty Jug as well....
P-47
(http://i.imgur.com/wqt40aN.png)
(http://combatace.com/uploads/monthly_04_2011/post-46431-0-76226400-1303855554.jpg)
So just like the maneuvering flap setting which really doesn't do anything for the aircraft, the dive recovery flaps are also "just there" in the game...
From the report "SUPPLEMENTARY REPORT ON TACTICAL SUITABILITY OF THE P-38G TYPE AIRPLANE AS COMPARED TO THE P-38F 3 May 1943
One of the conclusions was " c. The P-38G turns much better than the P-38F (will close 180° in 360° circle) due to maneuver flaps."
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ok what I want to do is be able to use my rudder pedals for left/right braking and also have a function where I can apply both brakes equally at the same time. there is a button setting for the controls that says flight wheel brakes but does not seem to work.
Where did you see a control for "color=red]flight wheel brakes[/color]"?
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default brake in AH is the space bar, not the rudder keys. I use the CH pedals, for rudder and the space bar for brake.
There are 3 default keyboard commands for brakes. The spacebar enables both toe brakes, while C is for the left toe brake and V is for the right toe brake.
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So just like the maneuvering flap setting which really doesn't do anything for the aircraft, the dive recovery flaps are also "just there" in the game...
Actually both features work properly. The dive recovery flaps delay the onset of compression and the 50% flap extension has the P-38's highest CLmax, just like they're supposed to.
Your point may be that they are not exactly like the real thing but I have to wonder why you even bring that up when the OP is asking about wheel brakes.
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Where did you see a control for "flight wheel brakes"?
Commands are grouped under Global, View, Flight, Gunner, Chute, and Vehicle. Wheel brakes are listed under Flight, hence "flight wheel brakes".
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Actually both features work properly. The dive recovery flaps delay the onset of compression and the 50% flap extension has the P-38's highest CLmax, just like they're supposed to.
Your point may be that they are not exactly like the real thing but I have to wonder why you even bring that up when the OP is asking about wheel brakes.
Well...since the dive recovery flaps should be also causing drag and they don't, I wouldnt say they work properly. And if you are insistent that the 50% setting is the maneuver flap setting, please make them deployable at 250mph per the manual.
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Well...since the dive recovery flaps should be also causing drag and they don't, I wouldnt say they work properly. And if you are insistent that the 50% setting is the maneuver flap setting, please make them deployable at 250mph per the manual.
Dobs,
Do you use combat trim or do you manually trim your planes ingame?
I ask because CT will make the dive flaps seem ineffective as it will dial in too much down elevator trim at the speeds where the dive flaps should be deployed. This has all be discussed and covered in the past! A retired trainer named Widewing made an extensive post on how and why they work. The amount of drag that they put out wont slow the plane in a dive and they were never meant to!
As for the maneuver flap setting in both the 51 and 47 the flaps deploy above 250,the 38 gets it's first flap setting at 250,whether or not this is equal to the maneuver setting/degrees I cant say as it's both above my pay grade and I'm not rated in a 38 or any plane for that matter. But again combat trim has an effect on flaps also as it just works off a simple x and y setting,at x speed it dials in y amount of trim and it doesnt take in account any other variables,flaps, damage, etc. basically all it does is to try and trim the plane to fly straight and level.
YMMV!
:salute
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The P-38 will extend 3 notches of flaps, i.e. 50% extension at 250 MPH TAS.
Lockheed's pilot notes state that the drag from the dive flaps is negligible.
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Well...since the dive recovery flaps should be also causing drag and they don't, I wouldnt say they work properly. And if you are insistent that the 50% setting is the maneuver flap setting, please make them deployable at 250mph per the manual.
Sorry to digress but wanted to address this a bit:
The first notch of flaps tend to be considered "combat" flaps in the 51/47/38. Now the actual degree of each notch for each plane may or may not be the same and may or may not be exactly the same as any preset degrees in the RL plane. For instance most of what I've come across in watching documentaries on P38 state that the second preset flap notch was considered the maneuvering flap setting and beyond that point you would be hurting the turn radius of the aircraft. Now I have not tested this in any scientific method myself but a few very notable p38 pilots in AH (soulyss as an example) swear that you get the most out of up to three notches in our 38's.
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Well...since the dive recovery flaps should be also causing drag and they don't, I wouldnt say they work properly. And if you are insistent that the 50% setting is the maneuver flap setting, please make them deployable at 250mph per the manual.
It's been a long time since the post, not sure if the original thread survived the migration a few years ago but it was explained in a post by HiTech around the time the P-38L was introduced into the game. IIRC, the flap deployment we see in the flap indicator isn't an accurate visual representation of the flap settings but that the flaps do work as they did in real life on the P-38. For game play reasons, the flap deployment for the maneuver setting was simplified in that the first notch of flaps is actually the maneuver setting.
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(http://uploads.tapatalk-cdn.com/20170104/7c69f8179d820419aef9fede0ac56cb9.png)(http://uploads.tapatalk-cdn.com/20170104/a1cbfe7054442c1144bd17c34436d2b6.png)
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(http://uploads.tapatalk-cdn.com/20170104/a04da6e8e9744d98b28eab0a89a27d61.png)
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Do you think the word "some" better describes a significant amount of drag or an insignificant amount? I think it's used to mean "not much" in the pilot notes.
Since the point of the dive flaps is delaying compression, not air braking, I think it's a good simulation. If I called it a complete model you could disagree.
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(http://uploads.tapatalk-cdn.com/20170104/7c69f8179d820419aef9fede0ac56cb9.png)(http://uploads.tapatalk-cdn.com/20170104/a1cbfe7054442c1144bd17c34436d2b6.png)
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I think the test mentioned in the 2nd image you posted was done using a P-51B as a test bed for dive flaps, and not a P-38. There was a thread that was posted about a year or so ago about the drag induced by the dive flaps. While the consensus was that there was some drag induced, it wasn't very much but there wasn't any concrete data found that showed how much drag was induced.
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(http://uploads.tapatalk-cdn.com/20170104/ec5c59a15ec23a5b592ae5221252bbbf.png)
(http://uploads.tapatalk-cdn.com/20170104/a35dde08223ab76205a729a8f010c66d.png)
You can see that they reference booms in the text and talk drag the bottom...
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(http://uploads.tapatalk-cdn.com/20170104/ec5c59a15ec23a5b592ae5221252bbbf.png)
(http://uploads.tapatalk-cdn.com/20170104/a35dde08223ab76205a729a8f010c66d.png)
You can see that they reference booms in the text and talk drag the bottom...
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Confused it with this test.
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930093004.pdf
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No worries...easy to do when you just see snippets of a tech paper:)
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Do you think the word "some" better describes a significant amount of drag or an insignificant amount? I think it's used to mean "not much" in the pilot notes.
Since the point of the dive flaps is delaying compression, not air braking, I think it's a good simulation. If I called it a complete model you could disagree.
There is a lot more going on than the writers of that manual knew at the time. They reference a high speed stall and loss of lift as the cause of the nose heaviness.
This has been subsequently discovered to be incorrect. You really can't rely on period aerodynamic explanations when it comes to transonic aero.
Critical mach number for an airfoil is the speed at which local flow becomes supersonic. When local flow exceeds the speed of sound a shock wave forms and as speed INCREASES ABOVE CRITICAL MACH the shock wave pushes the center of lift of the airfoil backward. This movement of the center of lift backward is what actually causes the pitch down moment of the aircraft.
This local supersonic flow happens on the curved surface of the airfoil (The top on a wing).
A dive recovery flap located on the opposite side well forward (33% of the chord in the case of the P38) is effective because it creates LIFT which effectively moves the center of pressure forward. This extra lift well forward effectively moves the critical Mach Number UP because it is countering the undesirable pitch down known as Mach Tuck, but it does this through aerodynamic forces that SHOULD be represented in the flight model.
LIFT produces INDUCED DRAG. Sticking something into the relative wind produces PARASITIC DRAG.
Something producing lift at Mach .67 creates a large amount of drag as well.
Producing lift at the 33% chord point also creates a pitch up moment (the ENTIRE POINT of the Dive Flap) This pitch moment should be present in all flight regimes and dramatically so at high Mach numbers.
So let's list the errors in the current P38 flight model that we can easily spot from this discussion.
1. The Dive Recovery Flap should produce Lift, Drag and have a SUBSTANTIAL pitch moment associated with its use. The report Dobs posted gives very specific numbers. 45 degree deployed 1.5 inch flaps at Mach 0.725 at 25,000 feet will produce a 3.5 G pullout. AHIII certainly does not model any of this.
2. The critical Mach Number is the ONSET of of the effects of "compressibility" or Mach Tuck. The critical MACH number of the P-38 is .67 in some sources and .69 in others. This is the Mach number where the effects BEGIN. The effects worsen with higher Mach numbers, resulting in the nose heavy dive. They should not be in full effect at .67 Mach as they are now in AHIII.
Here is a good intro on the gap between Critical Mach Number and the onset of compressibility and other effects.
http://www.flightlearnings.com/2009/08/28/high-speed-flight-speed-ranges/
So, no, it isn't a good simulation of the Dive Recovery Flap on the P-38. It appears to be a very simple code fix with no real attempt to accurately model the aerodynamics of the Dive Recovery Flap properly.
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There is a lot more going on than the writers of that manual knew at the time.
I'm confident the Lockheed engineers and test pilots could tell how much the P-38 slowed down when they deployed the dive flaps.
No worries...easy to do when you just see snippets of a tech paper:)
Speaking of snippets, you left out the part that supports your argument. What is the change in a P-38's co-efficient of drag when you employ dive flaps?
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This is the thread from the discussion awhile ago about the drag induced by the dive flaps on the Lightning.
http://bbs.hitechcreations.com/smf/index.php/topic,360029.0.html
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I'm confident the Lockheed engineers and test pilots could tell how much the P-38 slowed down when they deployed the dive flaps.
Speaking of snippets, you left out the part that supports your argument. What is the change in a P-38's co-efficient of drag when you employ dive flaps?
Actually it is in the diagram in my first "snippet" post.
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Actually it is in the diagram in my first "snippet" post.
You want to summarize that for us and tell us how much the P-38 should slow down or the total difference in drag?
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Looks like .4 difference in Cd at M .725.
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Looks like .4 difference in Cd at M .725.
That's for the 1" flaps on the model. It's indicative but it's not definitive for an actual P-38.
You'll also notice the P-38 dive flaps are a different design than the 1" flaps on the model, they are a V in cross section and I'm sure there's a reason for that but I don't recall any information on it.
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You are correct..V shaped due to the way they worked the hydraulics in to deploy them.
(http://www.kazoku.org/xp-38n/articles/p38diveflaps.gif)
From here is the only dimensions I can find...."8.5 Inchs and 58 inches in length" "Extrudes 5.5" from the wing to the piano hinge"
"One of the interesting new cases of P-38 pioneering is the use of recently added dive flaps to offset compressibility effect which shifted center of lift from fore to aft portions of wing. Due to the unusually high speeds attained by the heavy P-38 in power dives, shifting of the center of lift caused loss of normal control above the "hydrodynamic" speeds — where air reacts much like water — with a resulting tendency of the plane to go into an outside loop. Since installation of the flaps this characteristic has been overcome.
The flaps are fabricated of three layers of aluminum alloy sheet, flush riveted. They attach, by means of a piano-type hinge, along the same line at which the leading edge of the wing is joined to the outer panel. Actuation is electrical, with a high speed electric motor driving actuating screw mechanisms connected to a curved arm hinged to a fitting on the brace or rearmost of the two panels of the flap assembly. When lowered, the flap stands at an angle of 40° from the lower skin surface line, and at its farthest point is 5½" from the wing to the piano hinge by which it is attached to the brace panel. Two actuating mechanisms, side by side at the center, operate each flap, the actuating arms swinging downward through an opening in the wing skin. The flap and brace panels have a combined chord of 15½", divided 8½" to the flap itself and 7" to the brace. Length is 58". The mechanism is bolted to a heavy casting anchored to the lower skin structure and two wing ribs between which it is located." --http://migrate.legendsintheirowntime.com/LiTOT/P38/P38_Av_4408_DA.html (http://migrate.legendsintheirowntime.com/LiTOT/P38/P38_Av_4408_DA.html)
From a PDF: (http://migrate.legendsintheirowntime.com/LiTOT/P38/P38_redo.pdf (http://migrate.legendsintheirowntime.com/LiTOT/P38/P38_redo.pdf))
"When lowered, the flap
stands at an angle of 40° from the lower
skin surface line, and at its farthest
point is 5½ in. from the wing to the
piano hinge by which it is attached to
the brace panel. Two actuating mechanisms,
side by side at the center,
operate each flap, the actuating arms
swinging downward through an opening
in the wing skin. The flap and brace
panels have a combined chord of 15½
in, divided 8½ in to the flap itself and 7
in to the brace. Length is 58 in. The
mechanism is bolted to a heavy casting
anchored to the lower skin structure and
two wing ribs between which it is
located."
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You are correct..V shaped due to the way they worked the hydraulics in to deploy them.
I'm sure you meant to say the electronic actuator shown in the diagram.
I think a V bulge may have less drag than a plain flap.
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Those silly engineers went to all the trouble of installing an extension/retraction system, and weight, for those silly things when they could have just left em stuck out in the air since all it really effected was an increase in the dive speed.
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The question is how much drag. When you know that you can put it on the wish list.
Why double the Flap weight if it didn't improve it?
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i sure wish the data existed, wouldn't that be nice? But this sure makes for a lot of good book learning. I guess no data for the 47 either?
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I'm sure you meant to say the electronic actuator shown in the diagram.
I think a V bulge may have less drag than a plain flap.
Based on what? Your background in aero?
What part of the V is in the airstream? The backside is academic....see the diagram...it explains the shape.
(http://www.kazoku.org/xp-38n/articles/p38diveflaps.gif)
Electronic actuator. The part that pushes the Dive flap into the slipstream.
See the diagram with Cd levels...it quantifies the drag.
(http://uploads.tapatalk-cdn.com/20170104/7c69f8179d820419aef9fede0ac56cb9.png)
Tell me how the V shape affects the fact that the flap front face is in the windstream? 8" x 58" piece of metal stuck down 5" into the slipstream=
(http://history.nasa.gov/SP-440/p28a.jpg)
Toss in the statements from the pilot operating Handbook. "the flaps also add some drag...permits diving at a much steeper diving angle" "With dive recovery flaps extended before entering the dive, angles of dive up to 45 degrees may be safely accomplished."
(http://uploads.tapatalk-cdn.com/20170104/a04da6e8e9744d98b28eab0a89a27d61.png)
Note sure what else is needed....
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The question is how much drag. When you know that you can put it on the wish list.
Why double the Flap weight if it didn't improve it?
They quite obviously needed the structural strength to withstand the aerodynamic forces present at .67 Mach.
The V profile would have no effect on the induced drag value and very likely none on parasitic drag as the airflow turbulence aft of the trailing edge would be unaffected by the panel.
As can seen here
https://youtu.be/eBBZF_3DLCU
As for the correct drag value, the FM builder can just model the dive flap lift, drag and pitch values to match the real world known performance. Its not all that difficult.
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Based on what? Your background in aero?
That's correct. My opinion is based on my experience with aerodynamics. I'm not an expert but I know that aerodynamics are affected by the rear of the design as well as the front.
They quite obviously needed the structural strength to withstand the aerodynamic forces present at .67 Mach.
The V profile would have no effect on the induced drag value and very likely none on parasitic drag as the airflow turbulence aft of the trailing edge would be unaffected by the panel.
As can seen here
https://youtu.be/eBBZF_3DLCU
As for the correct drag value, the FM builder can just model the dive flap lift, drag and pitch values to match the real world known performance. Its not all that difficult.
I agree that strength could be a reason for the design but we're just guessing.
Your video of a flap does not show the airflow for a dive flap.
Where are you seeing lift, drag, and pitch values?
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This discussion anyways revolves around the same misconception that this is a brake. It's not a brake. Wasn't intended to BE a brake. It was intended to correct a specific aerodynamic problem with certain airframes within certain speed ranges that if left uncorrected tended to turn the pilot into a rider of the lawn dart. It just moves the airflow a bit so that doesn't happen.
A brake, As you would see on a dive bomber is a totally different animal. They're not only much larger but they protrude into the air stream much further. The intent of an air brake is to actually slow a dive bomber in a near vertical decent so it can accurately deliver orders before becoming part of the landscape. Different animal. Different intent.
These flaps are on fighters where speed is life. It was found that too much speed might very well not be and so this was the solution. I know some classify the 38 as a bomber but that's not really being serious.
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It is a dive recovery flap which moved the center of lift so the aircraft would remain controllable at speeds above .67 M and worked until .72ish.
The debate, Drano, is about how the current game models them. It just turns on a light and lets you go a little faster....
I was told earlier that the amount of drag they incur is not enough to be of any concern....yet it shows an increase of .4 in Cd in Diagram 16, and the Pilot Operating Handbooks says it allows you to dive up to 45 degrees (whereas before you were limited to 20) if you deploy them prior to the dive start.
The other part of the equation which is not modeled (and holds true for all aircraft) is the increase in drag caused by reaching critical mach..so the 38 goes rapidly into compressability.
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Drano the dive flap is not an air brake but it does add some drag, nobody is disputing that. The question is how much. There is also a question of a pitch response. I haven't seen any data that can be used in the flight model but there is anecdotal evidence.
The diagram Dobs posted is for a P-38 model glider testing different angles of a dive flap in a wind tunnel and comparing the drag. It doesn't tell us the drag of the actual dive flap on the P-38.
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Oh I get how it works. I fly the 38L pretty much exclusively, for years, and use the flap all the time when heading downhill, especially so at higher alts where your indicated airspeed is gonna pick up REALLY fast in the 38s. If I'm forced into J or G because of ENY or events I'm usually mashing the flap button in dives by force of habit. It's of course not there in the J or G and I've gotten myself into trouble getting faster and losing pitch control than I could in the L. Lose a lot of alt that way! IMO it does work as intended. However, with this caveat: if you have combat trim engaged and hit the flap, combat trim will almost if not entirely counteract its effect. Trim manually and it pitches up. Just how much it does or should is anyone's guess but it DOES happen. FWIW I'm a manual trim guy for this exact reason.
I'd agree that what data exists regarding the flap is almost purely anecdotal. It seems to ammount to they tried it, it worked, added it to later block Js and beyond and just went with it. Pretty much it. Nobody seems to have tested extensively JUST for the performance of the flap in RL. If they had, surely it would have cropped up by now after this horse has been beaten thru to the magma layer year after year and then maybe added to the model.
It just seems to me... And I may be missing the translation... That everyone focuses on the drag, the drag, the drag. That's Always at the center of this discussion. That leads me to believe peeps WANT to use this as a BRAKE, which it is NOT. It was never intended to slow the plane down. The confusion starts when people start referring to it as a brake. You need look no further than the subject line of this thread. Just might tend to give the impression it's gonna do something that it's never gonna.
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So knowing the deployment of dive recovery flaps moves the center of lift enabling control of the aircraft at higher speeds.....this is not the topic of discussion.
Knowing that it isn't a dive brake is not the topic of discussion.
(THIS IS A DIVE BRAKE)
(https://s-media-cache-ak0.pinimg.com/736x/c5/55/3b/c5553bb47532397eb95d63c641479e91.jpg)
What is the topic of discussion is that deploying them (RL) causes drag and enables you to dive up to 45 degrees without slamming straight into compressability. How much drag? .4 change in the Cd according to the diagram...what that means to the coder is up to them. Presently I turn the dive recovery flap on when I take the runway....because it has ZERO effect on the Flight model other than allowing you to go a little faster.
So yes we do understand they are not a brake, but trying to get them modeled where you can actually point your nose somewhat down hill without wearing out your trim button (and yes I fly manual trim as well).....
The other issue is compressability is modeled at .65 vs .67..... .65 was the placard limit to keep you out of compressability effects. Dive recovery flaps enabled you to go all the way to .72 before entering compressability.
Good input Drano (from a fellow 38 driver), and I know there was a lot of posts to read through...above is a summation of the discussion (not trying to be dick, just keeping it brief).
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So knowing the deployment of dive recovery flaps moves the center of lift enabling control of the aircraft at higher speeds.....this is not the topic of discussion.
Knowing that it isn't a dive brake is not the topic of discussion.
(THIS IS A DIVE BRAKE)
(https://s-media-cache-ak0.pinimg.com/736x/c5/55/3b/c5553bb47532397eb95d63c641479e91.jpg)
What is the topic of discussion is that deploying them (RL) causes drag and enables you to dive up to 45 degrees without slamming straight into compressability. How much drag? .4 change in the Cd according to the diagram...what that means to the coder is up to them. Presently I turn the dive recovery flap on when I take the runway....because it has ZERO effect on the Flight model other than allowing you to go a little faster.
So yes we do understand they are not a brake, but trying to get them modeled where you can actually point your nose somewhat down hill without wearing out your trim button (and yes I fly manual trim as well).....
The other issue is compressability is modeled at .65 vs .67..... .65 was the placard limit to keep you out of compressability effects. Dive recovery flaps enabled you to go all the way to .72 before entering compressability.
Good input Drano (from a fellow 38 driver), and I know there was a lot of posts to read through...above is a summation of the discussion (not trying to be dick, just keeping it brief).
No this is the topic of discussion..... the OP :D My haven't we gone far afield.
when I use the toe brakes on my rudder pedals I stop quickly and see a nose dip. If I use the keyboard nothing happens. Does the rudder pedal function cancel out the keyboard function?
whoops wrong forum
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100% correct Fugitive....talk about a thread hi-jack! :frown:
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No this is the topic of discussion..... the OP :D My haven't we gone far afield.
Oh crap! Sorry! I just saw all the P-38 charts and figured it was the next incarnation of the dive brakes discussion. Which it sorta ended up being hehe! Always a good convo tho.
Dobs, thanks for posting the pic of the SBD. It's easy to see the huge difference between an actual drive brake (on the SBD) and the recovery flap on the 38. As to the drag thing. I'd never thought of deploying the recovery flap at takeoff but as you say the drag is almost non-existent at slow speeds. That would stop you from forgetting to pop em before a dive! It doesn't really affect anything until high speed flight which is why it's so small. It needs all that extra pressure on that smaller area to do its job. It's applying drag sure. But it's different in that it only functions in a way that's measurable at high speed. It needs that specific airflow across it to function. At that point the drag at that particular point provides the force to move the airflow as intended.
The brake on the SBD is so much larger because it's designed to work at much slower speeds and actually prevent acceleration. Greater surface area at a greater angle at slower speed would get you the force necessary to slow the dive. If you reversed the flaps and put that little one on the SBD it'd lawn dart every time not having enough surface area to work against the airflow. Put the big'uns on the 38 and at high speed I'd guess they'd just rip away! It wasn't until later jets that employed speed boards for that and by then they were going faster still.
I remember reading somewhere that even after the flaps were adopted there was still debate about what caused and helped the problem. Some still thought the counter weights on the elevator were actually the answer and that's why they were retained.
Sent from my XT1585 using Tapatalk
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Yeah some Lt Col thought Counter weights were the answer....when he was proved wrong he wouldn't admit it and thus they stayed...
Changing the Center of lift was the issue....resulting in compressability effects. Dive recovery flaps were 8" frontal surface deployed at a 40degree angle 5" into the windstream and were 58" long. They effectively changed the center of lift back forward and enabled control until .72Mach.
In RL they have some drag...thus the ability to dive up to 45 degrees angle if you deployed them first....they also had the effect of causing a 3.5-4 G pitchup when deployed at speed:)
Anyhow, good discussion! <S>!
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That's correct. My opinion is based on my experience with aerodynamics. I'm not an expert but I know that aerodynamics are affected by the rear of the design as well as the front.
I agree that strength could be a reason for the design but we're just guessing.
Your video of a flap does not show the airflow for a dive flap.
Where are you seeing lift, drag, and pitch values?
There are many sources for the change in performance with the dive recovery flap deployed. We know its exact location and size on the bottom of the wing. It would be modeled like any other secondary flight control is modeled in game. There are not specific references for lift, drag and pitch for ANY flap system in the game yet somehow they are modeled.
It is a fairly simple process to model the dive recovery flap in its correct position on the P-38 and adjust the lift,drag and pitch numbers to match what we know happened in real life. That is how EVERY FM is built. Your insistence that there be a specific number or it doesn't get modeled is an invalid stance and rather telling if you hold some sort of decision making authority on FM's. If that were the case we would have no FM's at all.
Also, general aerodynamic principles apply across aircraft. What is observed to be true on one is generally true for all. So if you observe lift and drag (and the resultant change in pitch moment) from sticking a 40 degree board in the wind on X aircraft, you will observe the same general characteristics on Y aircraft.
No, the wind tunnel test was not a "dive recovery flap" but it was a deflected surface in the relative wind so the general performance would be similar and certainly close enough for our purposes.
But here is the equivalent of the dive recovery flap available to us on modern aircraft. It is a spoiler, which are mounted on the top of wings to produce negative lift and drag.
"Oh baby, we gettin' some drag there" is a direct quote from our intrepid videographer when the spoiler is deployed.
https://www.youtube.com/watch?v=UHbxDix8BHQ
My personal experience with deploying a 8 inch wide panel into the slipstream at 400 knots is that it is a dramatic event producing easily identifiable results. The aircraft pitches hard, rumbles at a level felt in your gut and slows down. And those are spoilers designed to be on the neutral point on the wing to minimize pitch.
In summary, we know the size and shape of the "dive recovery flap". We know its exact position on the chord line. We know it produces lift and drag. We know that lift and drag increase critical Mach number to .72 AND enables a 30 degree increase in dive angle. We know the application of the DRF at speed causes a 4 G manuever. That is enough data for ANY flight modeler to properly model the DRF on the P-38.
At this point I think you are just desperately clinging to your position for your own ego and not in the interest of the proper modeling of the aircraft in question.
Of course, I don't expect the DRF to be properly modeled. I know I am smashing my head against this particular wall with no particular hope of a positive result.
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it does seem as if the acceptance/ arguments for maintaining status quo is the quickest response from many, I know from what I have read , Hitec is proud of his and the teams work towards realism (rightly so), if the provided data is insufficient to improve on current models so be it. If it's just not worth the hassle so be it. Realistic? Doesn't seem to be hitting the numbers provided. I'll fly it anyway. I just shrug when the occasional person goes by and tells me I have my dive flap deployed in climb/cruise etc. in its current iteration it's just a light on the dashboard until I need those few extra knots downhill.
The P47 has the same issue - no effect on anything but an extension of max speed before compression. I have no data to say what it should do in that plane. Just an observation. Maybe a passionate Jug flyer will have it.
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There are many sources for the change in performance with the dive recovery flap deployed. We know its exact location and size on the bottom of the wing. It would be modeled like any other secondary flight control is modeled in game. There are not specific references for lift, drag and pitch for ANY flap system in the game yet somehow they are modeled.
It is a fairly simple process to model the dive recovery flap in its correct position on the P-38 and adjust the lift,drag and pitch numbers to match what we know happened in real life. That is how EVERY FM is built. Your insistence that there be a specific number or it doesn't get modeled is an invalid stance and rather telling if you hold some sort of decision making authority on FM's. If that were the case we would have no FM's at all.
Also, general aerodynamic principles apply across aircraft. What is observed to be true on one is generally true for all. So if you observe lift and drag (and the resultant change in pitch moment) from sticking a 40 degree board in the wind on X aircraft, you will observe the same general characteristics on Y aircraft.
No, the wind tunnel test was not a "dive recovery flap" but it was a deflected surface in the relative wind so the general performance would be similar and certainly close enough for our purposes.
But here is the equivalent of the dive recovery flap available to us on modern aircraft. It is a spoiler, which are mounted on the top of wings to produce negative lift and drag.
"Oh baby, we gettin' some drag there" is a direct quote from our intrepid videographer when the spoiler is deployed.
https://www.youtube.com/watch?v=UHbxDix8BHQ
My personal experience with deploying a 8 inch wide panel into the slipstream at 400 knots is that it is a dramatic event producing easily identifiable results. The aircraft pitches hard, rumbles at a level felt in your gut and slows down. And those are spoilers designed to be on the neutral point on the wing to minimize pitch.
In summary, we know the size and shape of the "dive recovery flap". We know its exact position on the chord line. We know it produces lift and drag. We know that lift and drag increase critical Mach number to .72 AND enables a 30 degree increase in dive angle. We know the application of the DRF at speed causes a 4 G manuever. That is enough data for ANY flight modeler to properly model the DRF on the P-38.
At this point I think you are just desperately clinging to your position for your own ego and not in the interest of the proper modeling of the aircraft in question.
Of course, I don't expect the DRF to be properly modeled. I know I am smashing my head against this particular wall with no particular hope of a positive result.
You imagine many things. :D
If you think a spoiler tells you how to model a dive flap we'll have to agree to disagree.