Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Widewing on December 24, 2007, 07:30:23 PM
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Flying the P-51D, exploring the absolute limits of its flight envelope led me to find and unusual quirk in its flight dynamics.
Most people would agree that no other fighter can burn off speed faster than an F4U, which can use (and did in real life) its main gear as speed brakes. I thought that as well, until today.
How about a P-51D flying at 330 mph, decelerating to 130 mph in less than 4 seconds, while presenting an almost impossible target? I filmed the following offline and asked Murdr to film it online, by following me. Done correctly (it takes a lot of practice), you can shake off anything on your six. At least for a brief period, perhaps long enough to reverse your fortunes. I tried this in about a dozen other fighters. None could perform the maneuver.
Fuel was 25%, meaning the fuselage aux tank was empty.
The films are very short, 15 to 20 seconds, but they are very interesting.
Mustang Maneuver 1 (http://home.att.net/~ww2aviation/MustangManeuver1.ahf)
Mustang Maneuver 2 (http://home.att.net/~ww2aviation/MustangManeuver2.ahf)
My regards,
Widewing
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Very interesting. This is similiar to a maneuver the 109 can perform, though it's maneuver is safe to use at 1000 feet abg.
Cheers Widewing
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That looks a lot like a maneuver I do with my radio controlled planes. To do it, I throw both control gimbals into the top inside corners, or both into the top outside corners.
That would be full throttle, full down elevator, full left aileron, and full right rudder. Or full throttle, full down elevator, full right aileron, and full left rudder.
I generally prefer to do it while nose up at least a bit, sometimes even vertical. Letting my controls go neutral stops the maneuver, at least with my RC planes.
I've done it with RC Corsairs, Ponies, Cherokees (Piper), Ultimate biplanes, and Pitts biplanes. The aerobatic planes do it best, followed by the war birds. The Cherokee will do it, but it's not as quick and impressive.
I don't know how close those planes are to AH's flight model though. For one, the power/weight ratio is probably quite different. The wing loading and airfoils are different too...
I've done that manuever in the TA, DA, and offline, and it does work, but I've never tried it in the MA. I know there were complaints for a while way back when of people doing snap rolls, and (lag?) made them look awful to the guy following. Those complaints seem to have died down, maybe the smoothing effect HTC added helped? Use to be called stick-stirring, even though it wasn't...
MtnMan
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Been watching Dogfights lately Widewing? :)
Looks like what Don Bryan of the 352nd described himself doing on November 2, 1944 to get a 109 off his tail.
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It would seem to have very limited use in a decent fight and would be an absolute last-ditch effort in a hope to evade a kill shot. Simply applying power and staying above would leave the attacker in an advantageous position. It would be interesting to actually encounter this maneuver though.
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Are you going to tell us how to do that? It's really hard to figure out just by watching the movie (the control surfaces don't move during playback).
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have been using the P51 as a low slow turn fighter for some time now, a number of years infact and often with moderate to excelent results.
great post widewing, hopefully some of the P-fifty runs will take note and stop being so timid. Mustang Sally says slow you mustang down.
edit: and the result of this type of flying is largely based on the perception your enemy has of you. If you have got in the opponents head and convinced them you are an easy kill then good things often come to those who take the risks.
too early and you are a sitting duck, too late and you get blasted.....but with perfect timing the mustang is formidable on full flaps and side slip.
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Originally posted by Anaxogoras
Are you going to tell us how to do that? It's really hard to figure out just by watching the movie (the control surfaces don't move during playback).
Push your stick all the way forward and all the way to the left while applying full right rudder.
Mtnman described it exactly.
While Murdr was flying behind me in the TA running film, I was actually able to flip the Mustang backwards and see his pursuing 109K in my windscreen as he blew past. He said there was no chance to get guns on the P-51 as it literally dropped straight down as it rotated.
Murdr, if you're reading this, maybe you could post a portion of the film...
My regards,
Widewing
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Used to be able to do something similar to that in the AH1 Spit 5. I think wetrat came up with it... the plane basically spun about its axis and would actually fly backwards for a split second before it stalled and spun.
It was really wierd, felt kind of like driving on ice feels, when the car just slews around without you really being in control of it.
It wasn't good for a whole lot, IIRC only a couple planes could do it very well (A6M, Spit 5).
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Shhhhh Widewing!!! Don't be giving away all the secrets of the Mustang!! ;) You have to make them earn it to learn about stuff like this!
But in the MA you have to do it with a lot more panache you know! More like this where you don't snap roll it and also lose so much altitude and control...
p-51d_flat_plating (http://brauncomustangs.org/films/film72_kumori_yak.ahf)
I filmed this a year ago in the MA so the terrain is one that doesn't exist. The fight was over some hilly terrain and I clipped a tree in the end.
I call it "flat plating" the Mustang in honor of Col. John Boyd's maneuver. It's a similar concept to his famous maneuver in the F-100 where you present as much of the aircraft's surface area into the freestream air using massive drag to dump your energy like no one's business. As described in the book by John Coram, it's sort of like turning a manhole cover from it's thin edge to it's flat side surface into the wind.
The secret is to maintain good control in the maneuver so that you recover very quickly from the "flat plate".
Of course though there is one huge difference. The F-100 had an awesome T/W ratio which allowed you to regain energy like crazy. You're pretty much out of luck in this category with the Mustang and better hope that you've somewhat equalized the energy margin between you and your opponent to take advantage of the maneuver.
I prefer to use it as my options are running out. In this case I thought I would try to suprise kumori in his Yak.
Tango, XO
412th FS Braunco Mustangs
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Looks like sort of a snap roll. Russian pilots used that kind of maneuver with the I-16 as well.
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Yeah, just from the description it sounds like a snap roll to me to.
I use it all the time, but then, I'm almost always about to get shot full of bullets.
I find it quite useful.
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Push your stick all the way forward and all the way to the left while applying full right rudder.
Ok, I was successful at approximating the maneuver, however the severe redout makes me believe that no pilot would attempt this without temporarily losing his eyesight. No doubt it is effective in AH.:lol
Granted, I have never flown a P-51, but I have done some loops, rolls and spins in a Grob http://www.grob-aerospace.net/index.php?id=88 (http://www.grob-aerospace.net/index.php?id=88) and boy do you feel the G's! :eek:
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Awww shucks... don't give the few secrets the pony has away!
This is a nice move unless you have a second, longer trailer. For a couple of secs, before you right the ship, you are pretty vulnerable. Anyone close would have gone by, no doubt pulling hard in reaction and not getting a solution. A second trailer will have a nice shot if he reacts accordingly.
Nice film. :aok
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Originally posted by Widewing
Push your stick all the way forward and all the way to the left while applying full right rudder.
Mtnman described it exactly.
While Murdr was flying behind me in the TA running film, I was actually able to flip the Mustang backwards and see his pursuing 109K in my windscreen as he blew past. He said there was no chance to get guns on the P-51 as it literally dropped straight down as it rotated.
Murdr, if you're reading this, maybe you could post a portion of the film...
My regards,
Widewing
Prior to the release of AHII the 109 could nearly turn around in it own length.
Maneuver was something like this..........
apply full left forward stick, apply full left rudder (for maybe 1/2 a second or even less), full reverse rudder, full back stick. Timing it just right was HARD but worth it!
In AHI the 109s had about as much down vator as up (which SEEMS correct according to info?) but when AHII came along that maneuver was no more, now 109 wallows and nearly refuses to react to down vator?
In fact IMHO HT may have over done the neutering of 109 down vator?
Also the 109 could do a nice left turn in AHI, that IIRC was reported as fact by opposing pilots?
Take it into a climbing left turn apply RIGHT rudder, then left rudder and cut throttle but keep it in a left turn! Plane should hang there just for a sec then drop and finish the left turn. I can't seem to get our 109 to do this now?
Another variation USED to be start same climbing left turn BUT at the top and after applying right then left rudder go full right stick right rudder, and full back stick.
All these maneuvers worked somewhat in other planes to a greater or lesser degree but the 109s were excellent.
Interestingly enough these maneuvers now SEEM to work in OTHER aircraft somewhat but the 109s are verbotten?
Tried many times and many variations but 109 SEEMS less then what it was.
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Originally posted by Widewing
Flying the P-51D, exploring the absolute limits of its flight envelope led me to find and unusual quirk in its flight dynamics.
Personally I think all the flight modeling is quirky to one degree or another. At times feels more like being in control of a remote controlled plane rather then actual flight.
So much analysis of "real world" to the game, really they are chalk and cheese there are basics to each aircraft which they represent but that's about it.
Makes for a fun game/environment though.
...-Gixer
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Mustang (http://trainers.hitechcreations.com/files/murdr/Mustang.ahf)
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Originally posted by wrag
In AHI the 109s had about as much down vator as up (which SEEMS correct according to info?) but when AHII came along that maneuver was no more, now 109 wallows and nearly refuses to react to down vator?
Try it with the aircraft trimmed for straight and level flight at whatever airspeed you're at.
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Originally posted by Guppy35
Been watching Dogfights lately Widewing? :)
Looks like what Don Bryan of the 352nd described himself doing on November 2, 1944 to get a 109 off his tail.
That was a fantastic show in that series.
Bryan was in deep trouble until he pulled that maneuver.
Edit : Just watched Murdr's film ... similar to Bryan move but Bryan did not flop as violently and as many time times as WW did.
Here is Bryan's move on youTube ... http://www.youtube.com/watch?v=NlfOWZHEGNk
Just as incredible, if not more, is Candelaria's move ...
http://www.youtube.com/watch?v=mdCm5z2RpI8&feature=related
and then to get guns on the guy ... amazing.
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Originally posted by SlapShot
That was a fantastic show in that series.
Bryan was in deep trouble until he pulled that maneuver. What was more amazing than the maneuver, was that he had the where with all to get a cockpit shot on the 109 ... amazing to say the least.
Edit : Just watched Murdr's film ... similar to Bryan move but Bryan did not flop as violently and as many time times as WW did.
I just picked up a copy of Flight Journal's WWII Air Combat issue (yesterday). There's an article by Lt.Col Bryan describing the fight shown on Dogfights. In the article, Bryan does not mention getting a shot at the 109. In fact, he states: " I did everything I could think of to lose this guy, except one. I knew I was had, so I used an old P-40 trick and initiated an inverted vertical reverse. In an instant, I was gone and hopefully left him wondering where the hell I went. I never met up with him again, and I was surely not going to look for him either. That son of a gun was good, he had a good airplane, and he knew what the hell he was doing."
There's no doubt that Bryan was describing the same huge brawl shown on Dogfights.
So, did he tell two different stories, or is the History Channel playing loose and fast with the facts? Bryan's After Action Report (see below) doesn't mention this other than to state he evaded a 109 with a snap roll.... And this snap roll occurred early in the fight (per the article), long before the encounter with the hot 109 driver. He may have left it out of the report, rather than admit it at the time. Either way, what was shown on Dogfights doesn't add up to the combat report submitted and verified.
(http://www.spitfireperformance.com/mustang/combat-reports/352-bryan-2nov44.jpg)
My regards,
Widewing
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Originally posted by Widewing
There's no doubt that Bryan was describing the same huge brawl shown on Dogfights.
So, did he tell two different stories, or is the History Channel playing loose and fast with the facts? Bryan's After Action Report (see below) doesn't mention this other than to state he evaded a 109 with a snap roll.... And this snap roll occurred early in the fight (per the article), long before the encounter with the hot 109 driver. He may have left it out of the report, rather than admit it at the time. Either way, what was shown on Dogfights doesn't add up to the combat report submitted and verified.
I think there is just a simple misunderstanding here. Bryan didn't claim to get a shot, and it wasn't presented that way on the History channel. He simply described how he evaded and got away from a 109. It was Candelaria who got the shot (and the kill) in a different incident.
It looks as though SlapShot posted the two separate links together, because they were both interesting P-51 maneuvers.
The History Channel Dogfights' presentation and the combat report appear to be consistent.
Badboy
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Originally posted by Badboy
I think there is just a simple misunderstanding here. Bryan didn't claim to get a shot, and it wasn't presented that way on the History channel. He simply described how he evaded and got away from a 109. It was Candelaria who got the shot (and the kill) in a different incident.
It looks as though SlapShot posted the two separate links together, because they were both interesting P-51 maneuvers.
The History Channel Dogfights' presentation and the combat report appear to be consistent.
Badboy
I watched that episode just the other day, and it showed Bryan doing his inverted reverse and I thought, hosing the 109 as it went by. Am I confused? I'll check You Tube as some putz surely posted a copy there.
(EDIT) Yep, I was confused.... Different P-51 pilot, I was thinking of this one. (http://www.youtube.com/watch?v=mdCm5z2RpI8)
Here's the Bryan episode (http://www.youtube.com/watch?v=NlfOWZHEGNk&feature=related)
My regards,
Widewing
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There is also an episode of Dogfights about a fight between an F-4 Phantom and a Mig in Vietnam. The F-4 was in trouble with a Mig on his tail, and the pilot did the following: shoved stick forward and left rudder, then full back and right rudder (possibly with crossed controls -- I forget that detail). It caused the F-4 to do a sort of back flip and dump speed very, very quickly. The Mig shot by without being able to get a shot.
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Originally posted by Widewing
I watched that episode just the other day, and it showed Bryan doing his inverted reverse and I thought, hosing the 109 as it went by. Am I confused? I'll check You Tube as some putz surely posted a copy there.
(EDIT) Yep, I was confused.... Different P-51 pilot, I was thinking of this one. (http://www.youtube.com/watch?v=mdCm5z2RpI8)
Here's the Bryan episode (http://www.youtube.com/watch?v=NlfOWZHEGNk&feature=related)
My regards,
Widewing
Sorry ... your right ... I got confused between the Bryan and Candelaria fights, both on the same episode I believe ... it was Candelaria that got the unbelievable span shot after his "funky" move ... Bryan just bugged out and was happy and satisfied just to still be alive.
Most interesting thing about both of these guys ... they just don't fit the stereotypical macho "fighter" pilot ... both act and seems like a couple of mild and meek men ... but get them in a Mustang and they transform.
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Nath put up a film on our squad forum of him doing this move in the old 109 G-10. IIRC Taki was following him in a N1K, nath did the maneuver and as he was facing the other way, fired a spud right into taki's face. Too funny.
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i have done an instant turn around using ruder i have done it acople of times not in combat but in the ofline
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No one commented on it so I assume folks didn't look at the film I posted earlier in the thread. Here's an animated gif of what I call the Mustang "flat plate".
(http://brauncomustangs.org/films/flatplate1.gif)
This looks a lot like Candelaria's maneuver described in Dogfights except that I didn't fire and hit anything in executing the maneuver!
Tango, XO
412th FS Braunco Mustangs
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I played around with this maneuver in the TA when I saw it on the Dogfights show just to see if it would work in AH. It seemed to work just fine.
Never tried it in the MA as I don't fly mustangs much.
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Originally posted by dtango
No one commented on it so I assume folks didn't look at the film I posted earlier in the thread. Here's an animated gif of what I call the Mustang "flat plate".
(http://brauncomustangs.org/films/flatplate1.gif)
This looks a lot like Candelaria's maneuver described in Dogfights except that I didn't fire and hit anything in executing the maneuver!
Tango, XO
412th FS Braunco Mustangs
Mabye i should practice more. the move you guys can do is amazing!
Gif make the move very clear. Now i see so to speak.
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That doesn't look like what I was talking about.
I'll have to see if I can still do it... yours looks more like what I would call a snap roll... you basically induce a stall but recover from it quickly so you only rotate once.
What we used to do sounds more like what NathBDP did - you were literally flying backwards for a half second or so until one wing dropped and you went into a spin.
I just called in a tail slide, it felt to me (funny how it could feel like anything.. but it does, to me at least) like fishtailing your car on ice. The back end of the plane rotated very quickly around (I could only ever do it clockwise, I think that is the only way it could be done) in the horizontal plane until it just stopped. Sometimes you'd get 180 degrees of rotation, sometimes more, sometimes less. It was nearly impossible to aim a shot while doing it, but you could hold down the trigger and maybe get lucky.
I could only ever do it in Spits and A6Ms, but it wouldnt surprise me if Nath could do it in a 109.
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Urchin:
Here's a snaproll quick recovery with a single rotation:
(http://brauncomustangs.org/films/snaproll.gif)
Here's a flat plate:
(http://brauncomustangs.org/films/flatplate2.gif)
Both maneuvers are initiated with an asymmetric wing stall. With the flat plate, however, there is a longitudinal pitching moment to flip the aircraft head over tail vs. just a rotation only about the lateral axis with a snaproll.
I don't have any idea what Nath used to do. In the past I've looked for different energy dumping maneuvers in the Mustang. The "flat plate" was just one of them :).
Tango, XO
412th FS Braunco Mustangs
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In the second clip of your flat plate - You see in the first part where the airplane seems to "slide" sideways before rotating, so that your p-51 seems to be basically rotating through a plane perpendicular to the plane of motion?
The "move" I am talking about starts similar to that, except the plane of rotation is the same as the plane of motion. The tail end of the plane basically skids around to the front, so that you are actually flying backwards.
I suck with ascii art, but I'll try to diagram this.
With your move, the plane is doing something like this
----------------> velocity vector
(x) (coming out of screen) nose at 'beginning' of your move
^
| axis of rotation
|
With the move I am talking about
---------------> velocity vector
(x) (coming out of screen) nose at 'beginning'
<-------> axis of rotation
So in my head, it is basically just like fishtailing your car on ice. You are pointing <- , while still travelling (however briefly) ---> .
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Seems like exploiting a buggy FM to me. Anybody tries that and they get no more consideration of skill from me than the average stick stirrer. They might put more effort into it, but the end result is the same and the average stick stirrer did it with better economy of motion.
EDIT: I'm not saying it doesn't take some skill to pull it off. Sure, knock yerself out. However, if I see it pulled against me I'm not going to think "Gee, whiz! That was a swell move!" I'm going to think "that stick-stirring son of a b----!" I'm just saying regardless of how hard the move is, it's probably not going to garner any respect.
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I understand what you're saying Urchin. I can't replicate that. With the flat plate I can get it to where you have more of a momentary flying backwards motion, but it's not completely 180 degrees of the direction of forward travel.
Here's an example of a flat plate with more "backwards" flight:
(http://brauncomustangs.org/films/flatplate3.gif)
Tango, XO
412th FS Braunco Mustangs
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Tango,
Those are very neat animated gifs. You should make one for most ACM moves and put them up in a training site of sorts.. or give them to HTC to put up on the main AH website.
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Thanks Tac. Actually I got the idea from Badboy who has posted a couple of animated gif's BFM (rolling scissors and barrel-roll defense) which are very nicely annotated with text too.
I just used this as a mechanism in lieu of being able to embed windows media or a youtube flash player into the thread.
Tango, XO
412th FS Braunco Mustangs
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Seems like exploiting a buggy FM to me. Anybody tries that and they get no more consideration of skill from me than the average stick stirrer. They might put more effort into it, but the end result is the same and the average stick stirrer did it with better economy of motion.
On the contrary, I find it an amusing testament to the accuracy of AH FM.
With the same sequence of stick inputs, the AH P-51 entered a state of accelerated stall that is virtually identical to those of the real-life P-51s piloted by Cpt. Bryan and Lt. Candelaria.
In other words, under similar conditions, the AH P-51 reacted almost exactly as the real life P-51 did.
Now if that's not a testament to how accurate and reliable AH FM is to the real thing, what is?
Anyone seen a P-51 in other sims ever do that? I sure haven't.
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Originally posted by Krusty
Seems like exploiting a buggy FM to me. Anybody tries that and they get no more consideration of skill from me than the average stick stirrer. They might put more effort into it, but the end result is the same and the average stick stirrer did it with better economy of motion.
EDIT: I'm not saying it doesn't take some skill to pull it off. Sure, knock yerself out. However, if I see it pulled against me I'm not going to think "Gee, whiz! That was a swell move!" I'm going to think "that stick-stirring son of a b----!" I'm just saying regardless of how hard the move is, it's probably not going to garner any respect.
One major difference is that these moves are intentional last-ditch maneuvers to get a bandit off your six. Stick stirring is that guy that sits 200yds in front of you and just bounces everywhere by frantic and random control inputs, normally performed by someone who has no clue how he might force you to overshoot.
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I dunno about those flat plate maneuvers dtango is illustrating, seems like you'd lose some control surfaces pulling that kind of thing, at the least, and find yourself in a really bad stall if not.
Seems to me to be a weird FM bug, but I am not an expert in any way, just seems kind of implausible.
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Originally posted by Krusty
EDIT: I'm not saying it doesn't take some skill to pull it off. Sure, knock yerself out. However, if I see it pulled against me I'm not going to think "Gee, whiz! That was a swell move!" I'm going to think "that stick-stirring son of a b----!" I'm just saying regardless of how hard the move is, it's probably not going to garner any respect.
If someone pulled that in front of me I would A) be in total awe or B)think they were hacking. Depends on who it was.
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I once spun a Typhoon flat around it's axis.
I was climbing from enemy's and as I ran out of steam I tried to dip the left wing. The torque wouldn't allow me to so I cranked full left rudder and the thing just spun flat around it's axis pointing the other way.
Had I been aware of what was going to happen I'd have had the perfect HO or deflection shots. They were all lined up.
I've tried this a few times since but haven't been able to do it again.
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Seems to me to be a weird FM bug, but I am not an expert in any way, just seems kind of implausible.
Apparently, it seems to be an already well known, real life phenomenon in the RC plane circles and acrobatic flight pilots.
I've consulted about this with our domestic flightsim community (obviously non-English speaking Koreans) and they've come back with a response that it is what's known as "a variation of a postive snaproll". It doesn't seem to be a common maneuver to do with warplanes, but the RC community definately has a lot of experience with exactly the same sequence of maneuvers WW or dtango has demonstrated above.
Therefore, it is not a "bug" or an "implausible" thing to happen - it's a real life aerobatic phenomenon that can be repeated with practice.
I'll see if I can translate some of their comments
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Originally posted by Kweassa
it's a real life aerobatic phenomenon that can be repeated with practice.
seeing it performed over & over shows it is not a fluke....keywords as Kweassa posted is Can Be Repeated With Practice
and a handful of players that are well known and have been here for some time have showed us just how much it takes to reallly learn your favorite plane type through & through......
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Okay, here's a comment from our flightsim community. Some of the oldtimers of AH might actually recognize him; "Skidrow" Kim is a long time aviation enthusiast and an AH player, used to fly way back in WB2 and AH1, with other great Korean pilots such as raomi "Rraf" and "feed".
Skidrow
It seems to me that it's a variation of a snaproll, which "kazi" once asked me about with 190s. This maneuver is already well known in the remote-control planes or acrobatic planes circles, and not an uncommon thing to witness.
The "pattern" of stall the plane falls under greatly differs according to which way you kick the rudder, or how you fiddle with the stick, and all such maneuvering is collectively referred to as "snap roll". A sort of a controlled spin, if you will.
RC planes or airshow planes are generally much more responsive than warplanes, and therefore it may be easier for the controllers or pilots to handle the plane under such a stall. The above accounts (accounts of D. Bryan and R. Candelaria) can be an example why it is more uncommon to expect such maneuvering in warplanes. It's probably due to the difficulty (and unpredictability) of the maneuvering that this certain "maneuver" never became a part of more or less 'orthodox' ACM.
The link below explains how such a maneuver is done with RC planes:
Hobby Info website link (http://www.hobbyinfo.co.kr/bbs/view.php?id=new_doc&page=1&sn1=&divpage=1&sn=off&ss=on&sc=on&select_arrange=headnum&desc=asc&no=88)
(*links to a Korean webpage. I'm sure the non-Korean speaking folk would still immediately relate the pictures that depict the RC contol and RC plane motion, with actual stick maneuvering in real-life planes)
I notice that Captain Bryan's AAR on the HTC forums also mention that he used a 'snap roll'. If I may add a bit, I think Widewing's maneuvering (as shown in the film) could be related to pure snap rolls, but dtango's "flat plate" seems to be a bit different.
A snap roll usually initiates an uncontrollable roll which rolls the plane a lot faster than normal aielron rolls (hence, the name 'snap roll'), but dtango's "flat plate" seems to be a cross between the 'snap roll' and an extreme barrel roll.
A snap roll may look very different according to how it is initiated, but the end result is always the same: with full stick and rudder input, the plane goes over the normal flight envelope.
This Youtube video (http://www.youtube.com/watch?v=S-8A4eDnz68), is from an RC simulation where you plug in the RC controls to your PC. It depicts two different forms of snap rolls.
And this Youtube video (http://www.youtube.com/watch?v=UjDwX1fmNzc) is of an actual aerobatics plane demonstrating snap rolls. Around 00:37 is a "negative snap roll", and 2:20 a "positive snap roll".
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Thanks Kweassa, DTango, and Widewing :)
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Er.... RC planes can also hover on their props.
Don't think a real life war plane can do that.
Just because a 2-lb. plane with enough thrust to break orbit can do it doesn't mean a 12,000lb plane with a single engine and slow acceleration can do it.
You get my point?
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I agree with Krusty (ohh that hurt to say)... I don't think that RC plane and real life warplane handling have much to do with each other.
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Candelaria's move reminds me of the "death blossom" from The Last Star Fighter movie, circa 1984.
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Originally posted by Krusty
Er.... RC planes can also hover on their props.
Don't think a real life war plane can do that.
Just because a 2-lb. plane with enough thrust to break orbit can do it doesn't mean a 12,000lb plane with a single engine and slow acceleration can do it.
You get my point?
Yes but the same physics apply to both RC planes and real aircraft.
The only difference between them is scale and P/W ratio.
If you scaled down the engine performance to the same scale as the RC aircraft's size/weight it would theoretically have the same performance (scaled down) as the real thing. And thus be able to perform the same maneuvers.
That an RC aircraft can perform similar maneuvers to real aircraft with engines that are not to scale doesn't mean the airframe cannot perform the maneuver. It only means there is a difference in power applied from the engine.
From what I've seen in the vids posted this doesn't look impossible, nor even improbable, just really hard and from the way the plane tumbles... that pilot is going to have a very painful next morning.
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Originally posted by Hoffman
Yes but the same physics apply to both RC planes and real aircraft.
You can't be serious. The laws of physics are the same for an elephant falling and a feather, but they forces ACTING on said objects are so far different as to be uncomparable.
Same for RC planes and real planes. You can NOT compare them in a serious manner.
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Originally posted by Krusty
You can't be serious. The laws of physics are the same for an elephant falling and a feather, but they forces ACTING on said objects are so far different as to be uncomparable.
Same for RC planes and real planes. You can NOT compare them in a serious manner.
Well ... I guess all the wind tunnel testing of scale aircrafts and vehicles is not needed anymore.
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You notice wind tunnel mockups don't actually fly?
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Originally posted by Krusty
You notice wind tunnel mockups don't actually fly?
grasping ...
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Likewise...
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You can't be serious. The laws of physics are the same for an elephant falling and a feather, but they forces ACTING on said objects are so far different as to be uncomparable.
Apparently, Krusty, under the current laws of physics that governs the Earth such a maneuver is;
a) possible
b) did happen
c) was documented
d) is repeatable
e) can be observed in airshows with real planes
f) already well known amongst real pilots
g) simulated by a FM claiming to be close to that of real life physics
h) simulated by scaled-down RC planes
It might not be possible in your laws of physics, but unfortunatelty, your laws of physics don't seem to exist outside your imagination.
Same for RC planes and real planes. You can NOT compare them in a serious manner.
If you keep maintaining this absurd attitude despite the variety of evidence and opinions laid before you, we might as well not take YOU seriously at all.
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Kweassa, none of that has been shown.
I go down your list categorically, and not one of those points has been proven in this thread. Not with any proof. 1 pilot's anecdotes 60 years after the fact on a show with less than reliable fact-checking doesn't cut it. RC planes don't cut it.
EDIT: P.S. Because it's in a flight model don't make it so. Because a RC plane can do it don't make it so. Nonsensical bullet points.
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*sigh*
Whatever you say, sahib.
Did I mention you can get all the evidence you want from Youtube?
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Show me a P-51 tail sliding backwards, in such perfect control that it can fire its guns at a plane following it, and then correcting without much loss of altitude. Yes, show me that on youtube.
Did you even bother looking at the animated GIFs supplied? Did you read the thread? Or just go to my name and post the opposite of whatever I said?
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Originally posted by Krusty
Likewise...
Hardly ... wind tunnel testing is used to test "real" physics upon scaled down surfaces, which correlate directly to the full scale subject ... there is no need to actually fly or for a vehicle to actually drive down a road ... in a controlled "scaled" environment to garner correct and telling results.
To broadly say that a properly scaled RC does not react the same as it's full scaled counterpart is not correct.
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Wind tunnels are used to test air flow over certain air shapes. They test for aerodynamics, drag, etc. They're definitely not being used in the same manner as a sideways-sliding P-51 going butt-first into the wind.
Wind tunnel models are so folks know when the wing rips off, to simplify it.
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Originally posted by Krusty
Wind tunnel models are so folks know when the wing rips off, to simplify it.
They also use them to test fast food burgers ;)
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Krusty, if an RC aircraft can do the maneuver, and the only difference between a P-51 and an RC aircraft are size and engine power.
Then the only thing necessary for the P-51 to duplicate the maneuver is to put the same forces in the same areas of the airframe. Which is entirely do-able.
That an RC aircraft can hover on its prop is irrelevant, engine power is irrelevant. The only relevent thing to be tested is whether or not the same amount of forces can be placed on the same areas of the airframe. Obviously because an RC plane is many times smaller and lighter than a P-51, it takes less of the same force to duplicate the maneuver.
But if you properly scale an RC aircraft to a P-51's size, and manage to get an engine that has the same power, torque, and ability in scale then there is nothing the real P-51 airframe can do that the RC aircraft cannot. Or vice verca. (Excepting of course that the P-51 has a pilot and pilot limitations over RC aircraft)
The only limitations would be gusts of wind having more effect on the RC aircraft due to less mass.
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My Filip 400 Sport warmliner does pretty wild snap roll but I don't have good clip of that. It kills speed from around 120-150km/h to less than 30km/h in couple seconds. What separates snap roll from barrel roll is that it is a stalled maneuver and the other wing stalls before the another which causes that typical rapid flick.
Same physics apply to real planes as RC planes, however RC planes are often purposedly designed for flick maneuvers. My favorite stalled maneuver is the climbing inverted flat spin ie it's a flat spin where the inner wing is stalled but the spinning speed is so high that the outer wing generates enough lift to stop sinking and actually makes the plane climb. I have not ever seen a real plane to do it. I'll try to take video in next indoor session because I have one plane which does it particularly well.
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The scale guys have another name for this and it isnt a snap-roll but its close to one. Ive been scratching my head trying to remember the name of it but I also know its called by different names around the world. A Czech pilot used this as the spring board for his lomcevak and I keep expecting Widewing to mention that. Back in the 70s Hoover had a friend that was always doing this move as a reversal in his stunts. His name will come to me when I least expect it.
Edit: Humpty-Bump
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Originally posted by Krusty
Wind tunnels are used to test air flow over certain air shapes. They test for aerodynamics, drag, etc. They're definitely not being used in the same manner as a sideways-sliding P-51 going butt-first into the wind.
Wind tunnel models are so folks know when the wing rips off, to simplify it.
Sorry to have to break this to you Krusty. That's incorrect. They do much much more than use them to just "know when the wing rips off".
The basic premise of scale testing of models is that if you can replicate a scale model of the aircraft (sometimes with even simulated working power-plants) and scale the reynolds and mach numbers then you have a high probability of a very reasonable estimation of how the aircraft might perform.
To give just an inkling, let's just talk about one (of many types) of wind tunnel tests- free-flighting models in wind tunnels. This goes all the way back to the 1930's for NACA where they free-flight wind tunnel test models by literally flying a scale model with prop running in a wind tunnel like the following...
1940- Free-flight wind tunnel testing of an XF4U-1
(http://lisar.larc.nasa.gov/IMAGES/SMALL/EL-2002-00167.jpeg)
Here's a more modern example of free-flighting an F-18
(http://lisar.larc.nasa.gov/IMAGES/SMALL/EL-2003-00414.jpeg)
Free-flighting in wind tunnels gives us all sorts of insights into the stability and control characteristics of aircraft for many different flight situations including stalls, spins, and very high aoa studies. Here's a sample of the type of stuff you can glean:
(http://brauncomustangs.org/images/x29-3.jpg)
This happens to be some analysis of the lateral-directional flight characteristics of this baby, the X-29 thanks to free-flight wind tunnel testing:
(http://brauncomustangs.org/images/x29-2.jpg)
Scale model tests in wind tunnels isn't done just for analyzing drag.
Tango, XO
412th FS Braunco Mustangs
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Originally posted by Chalenge
Edit: Humpty-Bump
No thats not it either. Its tough getting old.
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Wasn't there a manuever called the "Hartmann Escape" that Luftwaffe ace Eric Hartmann espoused that involved a stick in one forward corner with opposite rudder? This sounds very similar to that.
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Originally posted by Krusty
Wind tunnels are used to test air flow over certain air shapes. They test for aerodynamics, drag, etc. They're definitely not being used in the same manner as a sideways-sliding P-51 going butt-first into the wind.
Wind tunnel models are so folks know when the wing rips off, to simplify it.
Your absolutely sure about that ?
It is you that is over simplifying the realm of scale/wind tunnel testing and it isn't helping you.
Thanks to Tango for just scratching the surface of what has and can be done with wind tunnel testing ... beside seeing when wings rip off ... :rolleyes:
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I can tell you when the wings rip off. No need for a wind-tunnel. :D
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I realize they tell you a lot more than that, dtango. I was being super-simplistic.
They may tell you a lot about how the air flows over a perfect scale model of the real plane (NOT a non-scale flying styrofoam plane), but it's NOT going to tell you what forces of drag, inertia, torque, horsepower, and airflow, are all going to act and make a plane tumble out of the sky in full power combat manuvering.
Comparing RC planes (and diverting the topic to wind tunnels) to real P-51 mustangs is like comparing my bicycle to a F-1 race car.
To quote y'all "the same physics apply to both!!!" -- yeah, but not the same FORCES on both. Not the same interactions of forces, and not the same results.
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Originally posted by Krusty
....They may tell you a lot about how the air flows over a perfect scale model of the real plane (NOT a non-scale flying styrofoam plane), but it's NOT going to tell you what forces of drag, inertia, torque, horsepower, and airflow, are all going to act and make a plane tumble out of the sky in full power combat manuvering.
...To quote y'all "the same physics apply to both!!!" -- yeah, but not the same FORCES on both.
Sorry Krusty, that is very incorrect. Infact they tell you what the forces, inertia, torque, etc. are going to be - all that with scale models in wind tunnels. That's why they do scale model testing in wind tunnels.
There are certainly differences betweeen wind-tunnel models and testing vs. RC model flight. The differences have to do with the amount of fidelity from similarities (or lack there of) in reynolds numbers, mach numbers, mass distribution, etc. etc. compared to the full-scale aircraft in flight.
But the same physics apply to all (full-scale, wind-tunnel models, RC models) :).
Tango, XO
412th FS Braunco Mustangs
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Here is a snippet from an article on the NASA X-48 Blended Wing Body (BWB)
X-48A BWB-LSV Description
The BWB-LSV is a 14%-scale version of the 450-passenger study aircraft. Built primarily of composite materials and weighing about 2,500 lb., the platform features a wide arrowhead-like body that blends into tapered wings swept aft. Flight control surfaces, or elevons, span the trailing edges of the wings while the rudders are located in winglets on each wing tip.
Three 240-lb thrust turbojet engines, from Williams International Corporation, Walled Lake, Mich., were mounted on low aerodynamic pylons across the rear portion of the center body. All three engines will operate from a single fuel tank located near the vehicle's center of gravity. The maximum speed of the BWB-LSV would be about 165 mph.
Electric actuators in the flight control system link the exterior control surfaces with a central digital fly-by-wire flight control computer carried in the center body of the aircraft. The aircraft was to be flown by a NASA research pilot sitting at a cockpit station in the remotely piloted vehicle (RPV) facility at the NASA Dryden Flight Research Center. Instruments and displays in the RPV cockpit will provide the pilot with the same systems and performance data commonly displayed in conventional research aircraft cockpits.
Two small video cameras was be installed on the BWB-LSV. One, behind the mock cockpit windscreen, presents a forward-looking view on a large video screen in the RPV cockpit station. The NASA project pilot will use this view, along with the cockpit instrument array, to fly the vehicle. The second camera was mounted atop the rearward portion of the center body, to view external areas of the vehicle during flight.
Numerous sensors installed throughout the vehicle measure aerodynamic loads, air pressures, temperatures, engine performance, and other important test and research parameters during each flight. Data would be automatically transmitted to the Dryden mission control center and monitored during flight by project engineers and other members of the test team.
A spin recovery system built into the test aircraft would allow the vehicle to be flown to its maximum angle of attack and as slow as its stall speed. The system will be used to deploy a parachute if the vehicle begins an uncontrollable descent, such as an unrecoverable spin. The parachute attach line would be cut, separating the vehicle from the canopy as soon as stabilized flight could be resumed.
Construction of the BWB-LSV began in early 2000 and was scheduled for completion in late 2002. Integration and ground testing of the vehicle was to continue through 2003, followed by the test flight program. When assembly of the BWB-LSV was completed at the Langley Research Center, it was to undergo three months of wind tunnel testing at the Old Dominion University (ODU) Full-Scale Wind Tunnel Facility in Hampton, Va.
Research in ODU's massive 30 by 60-foot wind tunnel wwould include operating the engines and the external flight control surfaces at various air speeds. Data from this research will give engineers and designers a better understanding of the aerodynamics associated with the BWB's unique design prior to flight, as well as a unique opportunity to test the same vehicle on the ground and in flight.
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dtango, they cannot tell you the intertia, torque, or some other aspects of the real deal, because it is a model. Even if it has the scale WEIGHT, it does not have the same weight-to-surface area ratio. The same reason that most "enlarging-ray" movie plots are scientifically implausible. You can't just make something bigger and have it act the same way. The density increases while the ratio of mass to surface area decreases. There's a lot more at work than I think you give credit for.
They may tell you how the air will flow if you blow the air sideways, but they are NOT going to tell you how the combination of torque, drag, gravity, momentum/inertia and surface area into the wind are going to combine to show you how a plane will flip about.
I know wind tunnels are not my area, but even *I*'ve read enough about basic elementary school physics to piece this one together. An RC model will NOT act the same way a full-scale real warbird will. Period.
Again, unless you can show me a real P-51 that can hover on its own prop, climb, and land, flip over as if it weighed 6 ounces, and then do a barrel roll and a flip before going back to hovering, all in a box no bigger than its own wingspan.
P.S. The whole wind-tunnel side-track was Slapshot trying to divert the issue.
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Oh, and slapshot? We know that. That's what wind tunnels do. They let you know how the air will interact around a shape. It will be a big clue if the plane needs a larger stabilizer, or something. Most companies do use models to prove a design will fly. Even Leonardo used a models for his designs. It doesn't mean they are equivelant to the real thing.
Don't tell me you think the average RC pilot is as accomplished as NASA with their designs? Or are you saying NASA is so amateur that a Korean teenager can out-design them for the real deal?!?! (*gasp*)!!
By your logic, any 3-year old with a store-bought RC battery-powered plane has as much testing capability and flight capabilities as NASA and real aircraft combined. You're stretching.
EDIT: Let me try and put it in a way so simplistic even you could get my point:
Your RC plane weighs a few pounds, max. Wingspan (let's say) 2.5 feet. P-51 average wingspan, 50 feet. That's 20x the scale. Now weight... P-51 let's say 12,000lbs. Divide by 20 (the scale of the RC plane) and the little tiny 2.5-foot RC plane has to weigh 600lbs to even come close to approximating the P-51. I don't think even if it were made of solid lead it could weigh that much. I don't even know where to begin with the horsepower to weight comparisons, or surface area to weight ratios! Imagine a P-51D with a 2800-hp engine but it weighed only 1,000lbs. I'm sure such a mythical plane COULD hover on its prop and flip around like an RC plane, but the reality of physics doesn't hold up to that based on the real P-51s weight, mass, thrust, inertia, and aerodynamics.
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Originally posted by Krusty
By your logic, any 3-year old with a store-bought RC battery-powered plane has as much testing capability and flight capabilities as NASA and real aircraft combined. You're stretching.
Bad analogy Krusty. I think that NASA engineers have a lot more training, experience and comprehension than any 3 year-old.
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Originally posted by BaldEagl
Bad analogy Krusty. I think that NASA engineers have a lot more training, experience and comprehension than any 3 year-old.
By his logic, apparently they don't.
I, personally, think they're pretty smart.
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EDIT: Let me try and put it in a way so simplistic even you could get my point:
There ya go again getting all high and mighty and full of yourself and finally resort to a condescending attitude to really bring it home ... par for the course when someone takes you to task.
LOL ... I accomplished what I set out to do ... that a self-proclaimed know-it-all really doesn't know it all. Your very good at painting with a broad brush and your expertise at using smoke and mirrors is superb.
Want an example of a "broad brush" ...
You notice wind tunnel mockups don't actually fly?
Want an example of "smoke and mirrors" ...
Your RC plane weighs a few pounds, max. Wingspan (let's say) 2.5 feet. P-51 average wingspan, 50 feet. That's 20x the scale. Now weight... P-51 let's say 12,000lbs. Divide by 20 (the scale of the RC plane) and the little tiny 2.5-foot RC plane has to weigh 600lbs to even come close to approximating the P-51.
The scaling ratio is in size ... not weight ... too funny smarty-pants.
Take the exact same engine and machine every component down to it's 20x scale and assemble it and you would now have the correct "scaled" engine and mathematically ... it should fit inside the 20x airframe of the P-51.
I'll stop here as to not cause you any more embarrassment.
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1 word for this thread.
Hyperbole
I'll let you figure out where it belongs.:D
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Originally posted by mtnman
That looks a lot like a maneuver I do with my radio controlled planes. To do it, I throw both control gimbals into the top inside corners, or both into the top outside corners.
That would be full throttle, full down elevator, full left aileron, and full right rudder. Or full throttle, full down elevator, full right aileron, and full left rudder.
I generally prefer to do it while nose up at least a bit, sometimes even vertical. Letting my controls go neutral stops the maneuver, at least with my RC planes.
I've done it with RC Corsairs, Ponies, Cherokees (Piper), Ultimate biplanes, and Pitts biplanes. The aerobatic planes do it best, followed by the war birds. The Cherokee will do it, but it's not as quick and impressive.
I don't know how close those planes are to AH's flight model though. For one, the power/weight ratio is probably quite different. The wing loading and airfoils are different too...
I've done that manuever in the TA, DA, and offline, and it does work, but I've never tried it in the MA. I know there were complaints for a while way back when of people doing snap rolls, and (lag?) made them look awful to the guy following. Those complaints seem to have died down, maybe the smoothing effect HTC added helped? Use to be called stick-stirring, even though it wasn't...
MtnMan
This in modeling is what we call a snap, most of you know that already and myself knows how to do it. you can probably do it in the mossies and the 110's very well, but you have to know how to get it out of this manuver, down and opposite rudder the plane is doing.
Thats a neat trick right there.
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Originally posted by Krusty
Er.... RC planes can also hover on their props.
Don't think a real life war plane can do that.
Just because a 2-lb. plane with enough thrust to break orbit can do it doesn't mean a 12,000lb plane with a single engine and slow acceleration can do it.
You get my point?
Warplanes, or warbirds, will never hang on their prop because they just cannot have the power to pull the airplane strightup like that. Unless you put somthing that is way too overpowering for the plane, you will snap the wing in half just as a result as speed. Now some airplanes maybe able to "hang on the prop" but those airplanes are designed for that specifically. They are the exact same thing just smaller.
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Originally posted by Krusty
dtango, they cannot tell you the intertia, torque, or some other aspects of the real deal, because it is a model. Even if it has the scale WEIGHT, it does not have the same weight-to-surface area ratio....
....You can't just make something bigger and have it act the same way. The density increases while the ratio of mass to surface area decreases. There's a lot more at work than I think you give credit for.
I'm sorry Krusty. That is absolutely incorrect. Wind tunnel tests on models can give you all that. In aerodynamics it's called applying the right scale and similarity parameters. If we have the same similarity parameters (reynolds and mach number, mass distriubtion, control surfaces, etc.) between a scale wind tunnel model vs. real life then the ratio of forces experienced in the wind tunnel scale model are the same ones that you experience in full-scale. This is what makes wind tunnel testing even of value.
My little X-29 chart gives you hints at that, and that's only the tip of the iceberg. It tells you what they estimate the REAL X-29 is going to be like in terms of how it responds in the roll and yaw axis at different angles of attack. It's a direct result of analyzing the forces on the model like the following:
(http://brauncomustangs.org/upload/x29-3.gif)
These are the sideforce, yawing, and rolling moment derivatives from the model for different at a given aileron deflection across a range of flight angles of attack. They expect that full-scale X-29 to demonstrate the same values. This means that the ratio of forces acting on the model in the wind-tunnel replicates what the full-scale aircraft will experience at that same flight regime. This concept is paramount when it comes to the validity of tests on scale models in the wind tunnel.
Just for grins here is a picture I really like of the X-29 flying at 80 degrees aoa in free flight wind tunnel testing :).
(http://brauncomustangs.org/upload/fig11.jpg)
We haven't even touched on things like vertical wind tunnels and rotary balance tests which test a whole host of other characteristics like predicting the aircraft's stall and spin departure and departure recovery etc.
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Originally posted by Krusty
P.S. The whole wind-tunnel side-track was Slapshot trying to divert the issue.
I understand where the conversation has been going. I've purposely have stayed out of the whole discussion about RC craft etc. I don't know that anyone is showing that an RC P-51 will do the maneuver. The generalization from Kweassa and others are that real life acrobatic and RC planes can do some pretty amazing tricks, therefore since the physics are similar it's reasonable to assume that it's not impossible for a Mustang to do the same. From an aerodynamics standpoint, this is a much more compelling argument then saying it's not even possible because an RC model isn't a life-size aircraft. You chose to go down the line of reasoning which lead to the wind tunnel discussion about the value of scale models to defend the RC vs. life-size aircraft physics position.
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Slapshot: nice find on the X-48 :). I'm still amazed they put working "jet" engines in those free flight models.
Tango, XO
412th FS Braunco Mustangs
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Originally posted by Widewing
Push your stick all the way forward and all the way to the left while applying full right rudder.
Mtnman described it exactly.
While Murdr was flying behind me in the TA running film, I was actually able to flip the Mustang backwards and see his pursuing 109K in my windscreen as he blew past. He said there was no chance to get guns on the P-51 as it literally dropped straight down as it rotated.
Murdr, if you're reading this, maybe you could post a portion of the film...
My regards,
Widewing
Also sounds like the maneuver Erich Hartmann describes doing a number of times on the Eastern Front to evade an attacker on his six position and to force the attacker to overshoot.
ack-ack
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Why do you have so much trouble admitting you're wrong Krusty? This time, there was evidence in advance of the full refutal that you could have reassessed the basis of your arguments with, and recognized why dtango and others argued against you.. and seen what you argued was just plain wrong.
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OMG Krusty you are clueless, a snap roll is an accelerated stall and spin along its longitudinal axis while maintaining its general horizontal direction. It has everything to do with the angle of attack and the angle the wing stalls at. Every airplane is capable of spinning as well as snap rolling.
Pulling back abruptly on the stick increases the wings angle of attack to the point where the wing stalls.
Kicking the rudder induces yaw which sends the plane spinning on the horizontal, torque and gyroscopic precession also contribute or negate the affect depending on which way your propeller is turning and what rudder you hit.
Pushing the stick forward unloads the airplane and reduces the drag from the elevator essentially accelerating the aircraft spin.
A snap roll is one of the basic Aerobatic maneuvers. If you watch any Aerobatic videos you will see many snap rolls. I am amazed at how few know this maneuver on here.
When a snap roll is judged in Aerobatic competition the judges look for the nose being displaced up or down ( up = positive snap, down = negative snap) before the roll is initiated. IF they don't see the nose displacement then they will zero the snap roll figure and claim all the pilot did was an aileron roll.
I have to admit the depiction of the snap roll in dogfights was just plain bad. What they portrayed graphically was nothing short of garbage and looked nothing like a snap roll.
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Isn't that a slip? Turing rudder in the opposite direction as ailerons... If done while chopping throttle and deploying flaps in rapid succession you are GOING to decellerate and drop like a brick, works in the real world and AH. The trick is to reverse the manuver as soon a your opponant starts to pull in front as you. My PFI taught us about slips as a solution to being high and/or hot on approach, but the manuver has it's roots in ACM.
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I'm definetly going to try that move (and pratice it alot as well) once I get playing back in the game
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Hoffman-"Krusty, if an RC aircraft can do the maneuver, and the only difference between a P-51 and an RC aircraft are size and engine power."
Krusty-"Your RC plane weighs a few pounds, max. Wingspan (let's say) 2.5 feet. P-51 average wingspan, 50 feet. That's 20x the scale. Now weight... P-51 let's say 12,000lbs. Divide by 20 (the scale of the RC plane) and the little tiny 2.5-foot RC plane has to weigh 600lbs to even come close to approximating the P-51."
There are some other differences that do play a role, other than size and engine power. Almost always, the airfoils are quite different. RC planes generally have thicker-than-scale airfoils, and often, if not normally, different airfoils entirely than actual warbirds used. These different airfoils affect stalls, etc. An RC plane probably won't stall identically to its full-size counterpart. Wing loading varies as well. My RC F4U has a wing loading of around 34oz/sq ft, while it appears that the actual F4U-1A has a wing loading of around 36lb/sq ft. Those numbers look much more different than they really are.
There are lots of other differences. The end result still has the RC plane behaving very similarly to the full-size plane, and being influenced by the same forces. NASA thought RC planes flew similarly enough to full-size planes to make extensive use of RC space shuttles in design testing.
Krusty- Your knowledge of RC planes appears limited, and if you're trying to compare the itty-bitty department store RC planes with the ones referred to in this thread your confusion is easily explained. A 2.5 ft wingspan styrofoam RC corsair or pony look-alike is nothing like what we're talking about. That little thing DOESN'T fly like a full size warplane, any more than it flies like the "real" RC planes we're referring to. Sure the aerodynamic forces in play are the same, but it won't "look" the same in flight, or be capable of the same maneuvers the full size plane or the "normal" RC planes are capable of. Those little things are for little kids. Generally only have rudder, and MAYBE elevator control.
The RC planes I'm familiar with seldom have wingspans that small. They're larger, faster, heavier, and very true-to-life. My RC corsair has a wingspan of over 5ft, and weighs between 8 and 10lb. It's 1/7 scale. My largest RC plane had a wingspan of almost 12ft. The full size F4U has roughly a 41ft span.
You're weight scale conversion theory doesn't work the way you describe. As you double size, you don't double weight. Weight builds much faster, but not necessarily at a predictable rate. I have three firearms that shoot round lead balls (spheres). One is .50 cal, one is .75 cal, and one is 1 inch (1.00 cal.) The .50 cal ball weighs 175gr, the .75 weighs 565gr, and the 1 inch weighs around 1500gr. So as size doubled, mass increased much more rapidly (roughly 8x, in this case...)(in Avoirdupois weight 1lb = 7000gr). My 1/7 F4U does not, and SHOULD NOT weigh 1/7 the weight of the full size aircraft. Nor should the engine produce 1/7 the thrust, etc... Think of a 1 inch cube (1 sq inch). Now double the dimensions, to a 2 inch cube. The two inch x two inch cube is actually 8 sq inches. A 7"x7" cube would be 343 cubic inches. Assuming identical materials for the model F4U vs the full-size F4U we'd assume the full size plane would weigh not 7 times what the model weighs, but 343 times what the model weighs (2744-3430lb in this case). Identical building materials are obviously not used.
The redtail hawk and the golden eagle are VERY similar (but not identical) in shape and flight. The redtail has a 4ft wingspan, and is 21 inches long. The golden eagle has an 8ft span, and is 42 inches long (roughly). It would appear that the redtail is 1/2 the size (and it is, more or less). The redtail weighs 3-4lb. The golden eagle weighs 12-16lb. So size doubled, but mass quadrupled in this case.
Your arguments based on size/weight lead me to believe a P51 and a Boeing 747 don't operate on the same principals and respond to the same aerodynamic forces. Is the weight ratio between the P51 and the 747 correct?
Interesting discussion, but we're not comparing apples to apples...
MtnMan
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Originally posted by dtango
I don't know that anyone is showing that an RC P-51 will do the maneuver.
[
I've done it with RC P51's, F4U's, Piper Cherokee's, Ultimate Biplane's, and Pitt's Biplanes. All did the maneuver, but with varying "crispness". The Biplanes being aerobatic planes did it "best"(by far). The Cherokee does it the "worst".
For what it's worth, the RC P51 and F4U do it "much better" than the AH model does, at least in my eyes. The AH model seems to do it in slow motion compared to what I see from the RC planes. It's really not a "P51 thing", lots of planes would do it I expect.
I would expect this maneuver to be possible in the full size plane, but I sure wouldn't want to be involved, hehe. I wouldn't argue that the full size plane should be able to do it exactly like the RC versions...
MtnMan
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Originally posted by Kweassa
On the contrary, I find it an amusing testament to the accuracy of AH FM.
With the same sequence of stick inputs, the AH P-51 entered a state of accelerated stall that is virtually identical to those of the real-life P-51s piloted by Cpt. Bryan and Lt. Candelaria.
In other words, under similar conditions, the AH P-51 reacted almost exactly as the real life P-51 did.
Now if that's not a testament to how accurate and reliable AH FM is to the real thing, what is?
Anyone seen a P-51 in other sims ever do that? I sure haven't.
So basically, you are saying the Cobra wasn't a Russian invention, but North American?
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Well, I tend to be with Krusty on this one.
a) possible -Maybe, with luck you might even survive it, As far as I remember anykind of spinning was not recommended in Mustang. Do I remember wrong?
b) did happen -Really? We only have one person's somewhat inaccurate interpretation of what happened.
c) was documented -Errr, so?
d) is repeatable -In a real Mustang?
e) can be observed in airshows with real planes -Yeah, different "acrobatic" planes, very much different from Mustang.
f) already well known amongst real pilots -Maybe, although it may well be that you are not even talking about the same phenomenon.
g) simulated by a FM claiming to be close to that of real life physics -Sure, to me it looks like an anomaly in FM. In WW2OL flight model there does not seem to be anykind of damping for yawing momentum causing the 109 and P39 to be very unstable in yawing maneuvers. Is this hard to model in FM maths?
h) simulated by scaled-down RC planes -By scale Mustangs? Any vid? Any data of COG and weight vs scale? Depending of the speed in real plane the G stress might tear the plane apart.
From Homeboy's post:
"Never attempt to slow the aircraft by yawing the rudder."
http://forums.hitechcreations.com/forums/showthread.php?s=&threadid=223808
Skip Holm said that while 109s can be yawed significantly in flight to take a shot but Mustang cannot. Why do you think that is? The answer might be the huge side surface of the Mustang. I don't know really, but i suspect that to be the reason. Any ideas?
Besides what the hell does a modern wind tunnel have to do with this topic?
Was Mustang model tested in a modern wind tunnel and data gathered? Wind tunnel testing does not replace the need for real flight testing where the aircraft is spun and twisted and according that recommendations are made of permitted maneuvers. In wind tunnel you get the initial idea of what happens in different states of flight in u n i f o r m air flow. That means that spin tests need to be done with a real plane.
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Like so many times this thread too seems to be heading to personal mockery devoid of objective reasoning. :rolleyes:
-C+
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I would say this maneuver might be on the negative g-limits of a Mustang.
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you are saying the Cobra wasn't a Russian invention,
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How do you "invent" physics?
This thread passed me by intentionally as I never want my P51 FM to become unstable. Ive ended too many other P51s sorties while they were in this condition to want to go there myself.
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Two things:
1) The "Dogfights" episode portrays the spinning phase of the P-51 as having a considerable amount of time "pointing backwards", which is as mtnman pointed out a poor depiction. In essence the maneuver is a snaproll with a strong yawing momentum caused by a hard rudder input and momentum.
A "normal" snaproll would merely resemble an 180 degrees aileron roll, albeit considerably accelerated than usual, whereas the maneuver WW and dtango did (and presumably by the two P-51 pilots as well) partially resembles a barrel roll.
With the sudden pull of the stick and kick of the rudder the aircraft "snaps" violently at the apex of the "barrel roll" with some amount of yawing momentum, which at certain angles gives off the illusion that the plane is travelling rearwards - but actually does not, as demonstrated by dtango's "flat plate".
This is supported by the actual AAR provided by the pilots, where they themselves who initiated the maneuver, identify it as a "snaproll".
2) There are a plethora of actual footage of various warplanes, as well as airshowplanes, doing essentially the same maneuver as portrayed by WW and dtango, in YouTube. The same maneuver can be observed in some of the links I've provided, which contains an actual footage of RC planes doing it, also with a simulated footage complete with graphical descriptions explaining just what kind of flightpath the plane travels through.
The only difference would be the arc, width, and the severeness of the yawing motion as the plane snaps into a sudden roll seemingly resembling a barrel roll - hence, the reason why I've said it is "already well known amongst real pilots".
There is no 'anomaly'. The plane snaprolls as expected, except it isn't flying straight and level as it does it.
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"The "Dogfights" episode portrays the spinning phase of the P-51 as having a considerable amount of time "pointing backwards", which is as mtnman pointed out a poor depiction."
I don't really trust Dogfight series in how they present the maneuvers. I base this view on the numerous films I have seen from them. I agree that something resembling that surely happened but the exact execution of such maneuver is doubtful. In such wild maneuver you cannot be even sure where your eyes are pointing so if you see the pursuers nose you might see if from any angle your head happens to be if it happens to point at the pursuer.
If the depicted maneuver did happen it probably happened in quite a slow speed and such a quick recovery was a fluke, not something you can easily reproduce, or even want to.
-C+
PS. http://www.wwiiaircraftperformance.org/mustang/P-51B-Spin-Tests.pdf
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If the depicted maneuver did happen it probably happened in quite a slow speed and such a quick recovery was a fluke, not something you can easily reproduce, or even want to.
I'd agree to that upto a certain point.
Among the two depictions Cpt. Bryan, in his last-ditch attempt in a wild snaproll, lost control of the plane and fell straight downwards. Widewing, in one of his films, also loses control of his plane after the desired motion, and plummets for a while until he regains control. In case of Lt. Candelaria, I sincerely doubt he predicted the turn of events as he went into the maneuver, and my reasoning is his hybrid form of a barrel roll/snap roll was done with wide arc/radius as the enemy overshot, which landed him a one in a million shot.
In any case, (IMO) there's a reason why "snap roll" type of maneuvers never really makes it among the list of "official" ACM, since it is a result of a accelerated stall, rather than a plane flying within the the limits of its envelope. It is because the plane steps out of the envelope, that it rolls so fast, way faster than its normal rolling speed, in the first place. And as bozon once said, and I quote, "anything can happen when normal airflow is lost over the plane".
However, how a plane reacts under such conditions, whatever dangers there may be, is not entirely random. In some cases it is predictable, and "snap rolling" is a technique used by many pilots both in the game, and in real life. Would it be so hard to believe if it was just a normal snap rolling? People do it all the time.
Something not easily reproduced, I'll agree to that. However, it's not as if you are deliberately crashing your plane into a mountain. In both cases, Cpt. Bryan and Lt. Candelaria mentions they've practiced it before. How'd they practice such if it was something unreproduceable in the first place?
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Wow! Entertaining thread! I've been awol from ah for far too long evidently. Look what I've been missing!
A brisk salute: Excellent films and airplane handling! Great stuff.
Also: Lots of excellent historic and technical knowledge has been exhibited in this thread, so I'm hoping some of you would like to comment authoritatively on the any of the following.
All this talk of snap rolling P-51s made me chuckle as I recalled reading something in a P51 pilot's manual telling pilots NOT to try to snap roll the airplane. The fine AH films in this thread suggest it can be done...or at least something very similar to a snap roll can be done with our flight model...with practice. And of course, Capt. Bryan specifically mentioned performing a snap roll in his AAR. Yet, the P51 manual issues an official prohibition of the move.
I looked up the following quote from AAF Manual 51-127-5, (revision published 15, Aug 1945), p78 just to check and see if I was remembering correctly and sure enough:
"The aerodynamic characteristics of the P-51D are such that snap rolls cannot be satisfactorily performed. This has been proved by a long series of test flights. So don't try any snap rolls in an attempt to show that you're the guy who can do them. You'll invariably wind up in a power spin - and that's bad.
(Caution: Acrobatics must not be attempted unless the fuselage tank contains less than 40 gallons of fuel.)"
Jumping back to page 77 of the same manual to see what was said about power spins I found:
"Power-on spins are extremely dangerous and must never be performed intentionally under any circumstances....the spin tends to tighten, and there is a rapid loss of altitude. Recovery control will have no effect on the airplane until the throttle has been completely cut back."
It goes on to describe standard N.A.C.A spin recovery then a few paragraphs later:
"It may take up to six turns to recover from a two to five turn power spin. In this situation you may lose as much as 9000 feet of altitude."
First question: Does anyone know if this official 'don't snap roll the P51' order dates back to the time of Capt. Bryan's AAR or even before that? The manual I have is a revision that was essentially very late or post war as dated August '45. I wonder if earlier manuals say the same thing about snap rolls in the P51.
Secondly, does anyone know of technical and/or historic reasons other than those quoted above from the manual as to why snap rolls would be specifically excluded from authorized acrobatic maneuvers for the aircraft? The manual suggests that the power-on spin and required recovery are the main reason for the prohibition. The balance and behavior of the remaining fuel load is also suggested as a possible complicating factor to acrobatics in the Mustang (the < 40 gallon rule.) Anything else we should know about the P51D and its instabilities? Were there specific structural flaws in the Mustang that added further reasons to avoid snap rolling the aircraft?
If the anti-snap roll warning was part of Capt. Bryan's training, he seems to be thumbing his nose at that very manual and the notion that the P51 can't be snap rolled 'satisfactorily' in his AAR. He not only mentioned performing a snap roll, but claimed to do it as a combat maneuver. I imagine he probably did do it, and surely others at least tried it when possible despite any official warnings. He and other pilots likely tried to squeeze every bit of performance out their aircraft, and tried to learn every trick in the book to get the upper hand, knock down e/a get home alive. I know I sure would have.
We get a brand new, perfectly tuned and maintained aircraft every time we up in AH, so it's not that I'm worried about popping a few rivets or becoming a lawn dart while practicing. Just curious from a historic point of view.
Thanks for your time,
Hack9
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I believe the intent of Widewing's post was to encourage people of the value of spending time learning the nuances of any particular plane in Aces High and flying it to the limit. I posted the flat plate as an example of that. Nothing more, nothing less.
That's why I was and still am loathe to get dragged into a FM discussion about it. I've avoided commenting on the FM of the maneuver. With the flat plate, we are talking about a complex post-stall maneuver. The airplane is out of the envelope of normal flight and there is no simple way to mathematically evaluate it comparitively that I know of short of using navier-stokes equations.
The flat plate is a type of lomcevak maneuver where I'm also using the effect of the running propeller to induce particular motions while the airplane is temporarily in a post-stalled state. We know lomcevak's are real maneuvers. If I had doubts about the maneuver, it wouldn't be if the Mustang (or any other WW2 fighter) could initiate some type of lomcevak tumble like the flat plate, but if it could structurally survive it or not.
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Charge,
You obviously didn't appreciate any of my comments on wind tunnels :). I can't blame you for not following the entire thread to see why I even mentioned anything about them to begin with. It had nothing to do with proving or disproving that the Mustang could perform the maneuver. I was simply trying to clear up a misconception about scale models in wind tunnels.
Tango, XO
412th FS Braunco Mustangs
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Originally posted by Krusty
You can't be serious. The laws of physics are the same for an elephant falling and a feather, but they forces ACTING on said objects are so far different as to be uncomparable.
Same for RC planes and real planes. You can NOT compare them in a serious manner.
Have you ever seen a Yakovlev at an airshow? They do stunts like this all the time, though much more precise because the airframe is made exactly for aerobatics.
Just because a Mustang can flop around in the air doesn't mean it can hover on its propeller. Physics isn't symmetric...
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"his hybrid form of a barrel roll/snap roll was done with wide arc/radius as the enemy overshot, which landed him a one in a million shot."
I can agree with that.
I was trying to point out that Mustang had an issue why rudder was not recommended in slowing down the aircraft but I don't understand what it actually is. Was it to prevent the pilot from over-stressing the rudder construction since the fuselage has such a big side area to limit the slip or is the airframe prone to accelerated stall even with use of rudder? It may well be that despite the big side area the aircraft is somewhat unstable so that it really can enter a rather peculiar accelerated spin (notice the difference between B/D) but how could it instantly recover from it? The speed may be a rather deciding factor in such case considering keeping the controls effective but the manual (Hack's post) suggests that power on stalls are the most dangerous. Maybe it really can be safely executed by suddenly cutting the power in turn and pulling from the stick so that the a/c snap rolls and assisting a bit with rudder the resulting spin happens already in horizontal plane and opposite controls are able to get it under control until a vertical spin has time to develop. Power back on and you a back in the game.
But instantly recovering from a spin where you go tail first for a while? I find it very very hard to believe such maneuver to be possible with any WW2 fighter. Weight, G limits, COG vs COL or more precisely weight division in fuselage in relation to lifting or controlling forces and airfoil design prevent this IMO.
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AFAIK the point in Hartmann maneuver was to cause the shooter to be forced to push negative Gs so that any kind of accurate shooting was impossible since you were hanging from your harness.
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Finnish pilots did practice a maneuver called "impossible" or "senseless" where you deliberately entered a totally uncontrolled stalled neg G flight state from slow speed by pushing the stick e.g. foward left and stomping the opposite rudder fully down (IIRC), but the recovery took time and it was also considered a last resort maneuver just to get you a second chance if the assailant is about to get a sure kill. In training it was done with a trainer which had a reputation of being quite dangerous in its extremes.
-C+
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Originally posted by Charge
Finnish pilots did practice a maneuver called "impossible" or "senseless" where you deliberately entered a totally uncontrolled stalled neg G flight state from slow speed by pushing the stick e.g. foward left and stomping the opposite rudder fully down...
"Älytön" - literally tranlated as "senseless "etc. is just another name for the snap roll.
Generally dtango's film shows considerably yawed snap roll, reminds the flat spin.
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At low speeds, the P-51 had very poor yaw stability. This is why the US Navy did not adopt the P-51 for carrier use. Once the P-51H was developed, with its much larger vertical fin, the yaw stability improved dramatically.
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Originally posted by DiabloTX
Candelaria's move reminds me of the "death blossom" from The Last Star Fighter movie, circa 1984.
:rofl :rofl