Author Topic: Better haptics  (Read 3756 times)

Offline FLS

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Re: Better haptics
« Reply #30 on: October 27, 2013, 11:26:19 PM »
If real world airplanes require as much constant trimming as AH planes, then I'm glad I'm not rich and therefore cannot afford to fly real planes, because I would find that exceedingly annoying.

Trimming becomes automatic. That's modeled in AH with combat trim and the auto trim modes while retaining the option to manually trim if we wish.

Offline earl1937

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Re: Better haptics
« Reply #31 on: October 28, 2013, 05:35:16 PM »
There's a vast difference between the fighters of WWII that required manual trimming and today's modern fighters that auto trim to match the pilot's input.  Trimming the Mustang real world is a minor issue compared to the fun and excitement of flying a piece of history. 
:airplane: Ever hear the expression, "Thumb the Ponie"? On cross country flights of 1 to 3 hours, after climbing out in the P-51K, I would set up cruise power, just a tad of nose up trim, place my right forearm on my right leg, place my right hand thumb on the back of the stick, with just a little bit of pressure, that way you don't drive your self crazy trimming all the time. Now that is in smooth air, not bumps from heat thermals or thunder storms around or wind shear. The ones I flew had a lot of air time and the engines were getting a high time inspection every 25 hours, as it was not unusual to fly one with the prop gov surging 10 to 25 RPM, then you had to constantly work at trimming the aircraft. To get the ponie on "step", you had to do the opposite, a slight nose down trim and holding a little tad of back pressure with your fingers to maintain the negative attitude that you wanted when on "step". On landing, in the 3 point stance, I could feel a slight buffet on the rudder pedals just prior to touch down. The flaps caused the buffet, because it wouldn't do it with a no flap landing. While the ponie is not a difficult aircraft to fly, you must remember that it is a high performance aircraft and should be treated as such. While practicing approach to landing stalls with gear down and full flaps, with, say, 8,000 feet as your runway height, then 10 foot prior to settling into the 8K mark, pretend a deer runs out on the runway and you have to go around! If you "jam" the throttle wide open, first thing that happens is your do a 1/2 snap to the left, and having to get the nose down to gain speed, even though you have raised the gear, you look at the altimeter and it says 7,200 feet, then you realize, you don't do anything rapidly in the ponie near the ground!
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Offline Puma44

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Re: Better haptics
« Reply #32 on: October 28, 2013, 11:43:18 PM »
Good stuff Earl!  :aok I've not heard about "thumb the pony" but, what you describe makes perfect sense.  The go around stall to torque roll to snap is oh so accurate from my experience also.  Lots O Pony's ended up in fields on their backs with their legs sticking up in the air from that scenario.

« Last Edit: October 28, 2013, 11:49:47 PM by Puma44 »



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Offline hlbly

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Re: Better haptics
« Reply #33 on: October 29, 2013, 03:11:13 AM »
Don't be a silly hlbly.  If anyone reading this thinks you ignore everything I write and just make stuff up refer them to me.  :aok
Got no idea what you are trying to say here. As I clearly stated you ignored my test to reproduce bug on FFB . Also to address one of your other statements . You are once again wrong. Entirely wrong. Trim is not modeled in here. When stall was removed so was trim since it did nothing. Man why participate in discussion when you do not keep current ? Puma I have a couple of questions for you I hope you will answer sir . As a pony goes slower does the stick become easier or more difficult to move ? What causes the initial subtle shaking of the stick ? Does the airframe vibrate ? Is it just vibration from one or more of the control surfaces ? Maybe Earl will answer ?
« Last Edit: October 29, 2013, 03:13:33 AM by hlbly »

Offline Puma44

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Re: Better haptics
« Reply #34 on: October 29, 2013, 07:14:10 AM »
Hlbly,  I've  got  answers  for  you  and  will  answer  later  today.   I'm  getting  ready  to board  and  fly  home  and  thus  fat  fingering  on  my  phone.



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Offline hlbly

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Re: Better haptics
« Reply #35 on: October 29, 2013, 09:05:29 AM »
Thanks Puma if you could I would really love an explanation of what trim feels like on the stick. I appreciate your time sir thank you.

Offline Puma44

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Re: Better haptics
« Reply #36 on: October 29, 2013, 10:21:02 AM »
Got no idea what you are trying to say here. As I clearly stated you ignored my test to reproduce bug on FFB . Also to address one of your other statements . You are once again wrong. Entirely wrong. Trim is not modeled in here. When stall was removed so was trim since it did nothing. Man why participate in discussion when you do not keep current ? Puma I have a couple of questions for you I hope you will answer sir . As a pony goes slower does the stick become easier or more difficult to move ? What causes the initial subtle shaking of the stick ? Does the airframe vibrate ? Is it just vibration from one or more of the control surfaces ? Maybe Earl will answer ?
1) As with most airplanes, the faster the airspeed, smaller control movement is required, and so as airspeed gets slower more control movement is required.  So, it can be looked as more stick movement vs difficult to move.

2) Your next three questions I'm assuming you are referring to a stall?  If so, without getting into complex aerodynamics, consider the example we were taught in USAF Pilot Training.  The approach to a stall was described as pebbles, rocks, and boulders to explain the progressively increasing separation and turbulence as the air flow across the top of the wing stopped producing lift.  As the approaching stall develops, there is a gentle vibration felt in the stick and rudder peddles from the airframe vibration an thus pebbles, rocks, and boulders as the stall is fully developed. I found the Mustang to be very solid and predictable after doing the usual array of stalls; clean, fully configured, and accelerated.  As the stall would develop, the Mustang would recover quickly when the angle of attack was reduced. Especially in accelerated stalls, it would recover immediately upon breaking the AOA.  My instructor also had me do cross controlled accelerated stalls.  In a hard right turn, with too much left rudder, the Mustang immediately snapped to the left and would gone into a fully developed "Mr Toad's Wild Ride" if the AOA wasn't immediately reduced. Once this was done, the Mustang was immediately flying and in full control.  Another interesting thing my instructor pointed out during the accelerated stalls and high G turns, is a very unique buzzing sound which he said was believed to be the airflow over the wing roots during these maneuvers.  Also during high airspeed, high G maneuvering at the burble (pre pebble), the burble would remain after reducing G load.  My instructor said that the burble or slightly disturbed airflow would remain on the wing until we "bunted" over to smooth the airflow out, and he was right.

So, is this what you were asking about or did I miss the intent of your question?  Ask away if I did.  :salute

Trim on the stick and the feel is akin to fine tuning your radio on a stereo channel, I.e. make it smooth. Trim is intended to reduce control forces to make the pilot's job easier.  For example, flying along at cruise power with the controls properly trimmed results in the pilot having a light grip on the controls.  When it's time to slow down and configure to land, the nose will get heavy because the aircraft is no longer trimmed for the flight condition. So, the pilot will have to apply nose up trim to reduce the control loading that results.  An adjustment in rudder trim to the left will also be required when power is reduced.  The Mustang requires constant trim adjustments as flight conditions and power setting are changed.  But, one of the many great design features of the Mustang are the large trim wheels just to rear and below the power quadrant.  I found it very convenient and easy to trim as I gained proficiency.

Earl, please jump in here if you've got anything to add or explain in a different way.   :salute
« Last Edit: October 29, 2013, 10:36:40 AM by Puma44 »



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Offline hlbly

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Re: Better haptics
« Reply #37 on: October 29, 2013, 11:21:09 AM »
Okay puma let me see if I have this right. As a Pony approaches stall it requires more stick movement rather than the stick requiring less force to move . Is that correct ? As it goes faster it requires less movement but force required remains the same ? Like driving a car with power steering ? The faster you are going the less you need to move the steering wheel to do what you want . The effort to move the steering wheel remains the same ? Next if you could give me an analogy for trim that uses a tactile reference. Please explain what you mean by heavy . Last let me see if I have the pebbles rocks boulders analogy correct.  As the aircraft approaches stall and the airframe begins to buffet. First you feel the pebbles small vibrations . As you get closer you feel the rocks moderate vibration . Just before stall you get the boulders . Severe vibration . Does the frequency of the vibration change as well ? Say the pebbles have a lower frequency and the boulders a higher frequency of vibration ? Puma I really appreciate you taking the time to explain this in layman terms. Please let me know if I have missed anything.

Offline Puma44

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Re: Better haptics
« Reply #38 on: October 29, 2013, 11:54:57 AM »
You've pretty much got it Hlbly.  The pebbles (tap,tap,tap) are kind of a gentle rumble if you will and a bit more rapid because airflow is still moving somewhat efficiently across the wing, as it progresses the rocks (thump,thump, thump) are an indication of more airflow disturbance, and the boulders(bang, bang, bang) are the last warning before the stall is fully developed and lift is lost.  As far as frequency goes, probably more in the beginning and less at the end game.

The stick movement and force or load are dependant on the configuration.  High speed, accelerated stall, responsive stick input, honk the stick back, she digs in and pebbles,rocks, boulders progress rapidly (frequency?).   A fully configure landing stall with flaps 50, this stick is somewhat sloppier than above and the pebbles, rocks, and boulders develop more slowly (frequency?).  Again, the Mustang is very honest and predictable.  But, like ANY airplane, a pilot can get himself in a square corner and have areal bad outcome.

Earl mentioned the deer on the runway scenario and what he experienced.  I was taught to perform a go around with partial increase in power, flaps to 30 (less drag and more lift), trim, and then flaps 20, trim, flaps 10, trim, flaps up, trim, landing gear up, trim.  See the constant need for trim with configuration change?  My instructor said that most Mustang go around accidents result in a balked landing or bounce while trying to save the landing.  In the process, airspeed drops off, the safety margin between flying speed and stall speed closes, panic reaction occurs, a yank on the stick occurs creating a stall and immediate application of full power results in what Earl described below; the stall occurs and the high power setting creates a torque roll, and over she goes onto her back with no altitude to recover.  Earl needed 800 feet to get back under control in that situation.  At only a few feet above the runway, it's all history from there.

Your power steering is another good analogy to describe use of trim.  In trim...power steering, out of trim.....power steering has failed.
« Last Edit: October 29, 2013, 11:57:57 AM by Puma44 »



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Offline hitech

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Re: Better haptics
« Reply #39 on: October 29, 2013, 12:34:00 PM »
The only use of Funky Chicken I have ever heard, is how a pilot looks when recovering from G lock.

Also I had a very difficult time feeling the edge in the Mustang for accelerated stalls as compared to other aircraft I a have flown.  But a quick forward stick and rudder stomp always hooked me right back up after about a 1/4 to 1/2 snap. These were done at around 200 mph.

HiTech

Offline FLS

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Re: Better haptics
« Reply #40 on: October 29, 2013, 12:59:03 PM »
Got no idea what you are trying to say here. As I clearly stated you ignored my test to reproduce bug on FFB . Also to address one of your other statements . You are once again wrong. Entirely wrong. Trim is not modeled in here. When stall was removed so was trim since it did nothing. Man why participate in discussion when you do not keep current ? Puma I have a couple of questions for you I hope you will answer sir . As a pony goes slower does the stick become easier or more difficult to move ? What causes the initial subtle shaking of the stick ? Does the airframe vibrate ? Is it just vibration from one or more of the control surfaces ? Maybe Earl will answer ?

Stall was removed? Trim was removed? Really? The only thing removed was the vibration you complained about.

The only bug you went on about in my old FFB thread was the reversal bug which I already addressed in this thread. I also explained in this thread why you don't feel the trim forces with a G-940.  That's why I pointed out that you're ignoring everything I write here.

The G-940 becomes harder to move with speed, as it should, unless it has the latest firmware, as I already mentioned. I explained this 3 years ago and again in this thread. That's a hardware problem that HTC cannot fix. You can't expect them to waste their time just because you don't get that.

The only thing missing from Aces High FFB is the pre-stall vibration that you convinced them to remove. Before you complain again that I don't know what I'm talking about or I'm standing in the way of progress try rereading what I wrote. Slowly.

You've been wrong, rude, and insulting for 3 years now, all because I asked you once not to go off topic in my FFB thread with the unrelated reversal bug.

« Last Edit: October 29, 2013, 01:07:52 PM by FLS »

Offline Puma44

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Re: Better haptics
« Reply #41 on: October 29, 2013, 02:15:29 PM »
The only use of Funky Chicken I have ever heard, is how a pilot looks when recovering from G lock.

Also I had a very difficult time feeling the edge in the Mustang for accelerated stalls as compared to other aircraft I a have flown.  But a quick forward stick and rudder stomp always hooked me right back up after about a 1/4 to 1/2 snap. These were done at around 200 mph.

HiTech
It kinda got used for all sorts of "Hey watch this" type maneuvers, HiTech.



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Offline gyrene81

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Re: Better haptics
« Reply #42 on: October 29, 2013, 02:29:48 PM »
It kinda got used for all sorts of "Hey watch this" type maneuvers, HiTech.
those are not good words in the air, on the water or on the ground...
jarhed  
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Offline earl1937

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Re: Better haptics
« Reply #43 on: October 29, 2013, 02:53:19 PM »
Okay puma let me see if I have this right. As a Pony approaches stall it requires more stick movement rather than the stick requiring less force to move . Is that correct ? As it goes faster it requires less movement but force required remains the same ? Like driving a car with power steering ? The faster you are going the less you need to move the steering wheel to do what you want . The effort to move the steering wheel remains the same ? Next if you could give me an analogy for trim that uses a tactile reference. Please explain what you mean by heavy . Last let me see if I have the pebbles rocks boulders analogy correct.  As the aircraft approaches stall and the airframe begins to buffet. First you feel the pebbles small vibrations . As you get closer you feel the rocks moderate vibration . Just before stall you get the boulders . Severe vibration . Does the frequency of the vibration change as well ? Say the pebbles have a lower frequency and the boulders a higher frequency of vibration ? Puma I really appreciate you taking the time to explain this in layman terms. Please let me know if I have missed anything.
:airplane: In the "Ponie", there is a wide range of control movement required to do certain procedures and or maneuvers! Think of it like this, and you will find it true with about any aircraft, (can't speak of jet aircraft, with auto-trim), The faster you are going, the more sensitive the controls, which require less movement to obtain the attitude that you want the aircraft in. The slower the speed, of course, now the controls are not as effective and require much more stick and rudder and elevator movement to maintain the attitude and airspeed which you want. As far as "flutter" or viberation of control surface's, you won't notice much in the ponie, except when you have ords racks hanging under the wing. Then you have a whole new set of aerodynamics which affect the aircraft at slow speeds, such as landings or stall practice.
The ponie has always had a bad rep about snapping to the left in stalls, but what I have found out is, most people have heard this and guarding against the dreaded snap, they ride a little right rudder and the cross control situation does in fact produce a snap to the left.
The elevator and rudder are affected by the down flaps at slow speeds for landing, but with attention to trim, its no problem as I remember. There is no danger of the Ponie going into a "Deep" stall, as at any fuel load, the nose is to nose heavy in the slow speed realm of flight and the nose will come down if you run out of airspeed, with no power.
Now some of the fighters, like the ponie, had a low frequencies antenna running from behind the cockpit back to the vertical stabilizer and that could be causing some of the viberations which you hear people talk of. Below is a link to a good picture, showing the low frequencies antenna.

http://www.354thpmfg.com/Fighters/P-51/P-51DMustang.pdf

You won't see the LF antenna on all the privately owned Ponies running around the country, because LF is no longer used like it was during the war years of the 40's and 50's. Maybe that is where AH got the viberation deal on the Ponie! Not sure of that though.

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Offline Puma44

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Re: Better haptics
« Reply #44 on: October 29, 2013, 02:53:48 PM »
those are not good words in the air, on the water or on the ground...
Oh, so true!



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