Aces High Bulletin Board

General Forums => Wishlist => Topic started by: olds442 on December 08, 2013, 11:48:30 AM

Title: Prop wash
Post by: olds442 on December 08, 2013, 11:48:30 AM
I think their ought to be prop wash as it changed combat sometimes. I remember this one story where a p51 was almost kicked inverted from prop wash at low speed when he was on a 109
Title: Re: Prop wash
Post by: Arlo on December 08, 2013, 12:18:31 PM
I think their ought to be prop wash as it changed combat sometimes. I remember this one story where a p51 was almost kicked inverted from prop wash at low speed when he was on a 109


Has any online sim ever managed to model such? I couldn't add my +1
without understanding the intricacies of what it would possibly take
to code this monster in. The flight model in this game is pretty darn
good, as is.
Title: Re: Prop wash
Post by: guncrasher on December 08, 2013, 01:24:39 PM
imagine taking off with ten friends?



semp
Title: Re: Prop wash
Post by: olds442 on December 08, 2013, 01:36:28 PM
imagine taking off with ten friends?



semp

Timed take offs... Or have it disabled on the ground via arena settings
Title: Re: Prop wash
Post by: Arlo on December 08, 2013, 01:44:34 PM
Timed take offs... Or have it disabled on the ground via arena settings

You can't piecemeal realism in a game and expect it to work out. Players wanna take off
without having to take a number. Coding prop wash is probably a big enough monster
without having to make it even more specific as to where and when it takes effect.

I respect your desire. I'm just not sure this is an 'easy' wish nor one that takes precedence
over things we know Dale can code without taking more time and effort than the worth in
the end.
Title: Re: Prop wash
Post by: earl1937 on December 09, 2013, 12:02:34 PM
Timed take offs... Or have it disabled on the ground via arena settings
:airplane: One of the things I have started doing with B-29 mish's is having them look at the "Pick-up mission roster", see where their name is and that is the position that they will take off in. Sometimes I write that down and call out when so and so is supposted to roll. Of course if you do take off inside someone else aircraft, after the gear is up, just a touch of J or L will move you right out of the other aircraft where you can see! LOL
Title: Re: Prop wash
Post by: Traveler on December 10, 2013, 10:07:18 AM
I think their ought to be prop wash as it changed combat sometimes. I remember this one story where a p51 was almost kicked inverted from prop wash at low speed when he was on a 109


Prop wash did not cause the P51 to start to roll inverted.  Prop wash causes a yawing effect at low airspeed.  More likely it was Propeller torque effect which causes a rolling and is corrected with aileron controls
Please consider the following:
Prop wash
A propeller pushes air not just horizontally to the back, but more in a twisting helix around the fuselage (clockwise as seen from the cockpit). As the air whirls around the fuselage it pushes against the left side of the vertical tail (assuming it is located above the propeller's axis), causing the plane to yaw to the left. The prop wash effect is at its greatest when the airflow is flowing more around the fuselage than along it, i.e., at high power and low airspeed, which is the situation when starting the takeoff run.

Propeller torque effect
Torque effect is the influence of engine torque on aircraft movement and control. It is generally exhibited as a left turning tendency in piston single engine propeller driven aircraft.
According to Newton's law, "for every action there is an equal and opposite reaction," such that the propeller, if turning clockwise (when viewed from the cockpit), imparts a tendency for the aircraft to rotate counterclockwise. Since most single engine aircraft have propellers rotating clockwise, they rotate to the left, pushing the left wing down.
Typically, the pilot is expected to counter this force through the control inputs. To counter the aircraft roll left, the pilot applies right aileron.
It is important to understand that torque is a movement about the roll axis. Aileron controls roll. Prop torque is not countered by moving the rudder or by setting rudder trim. It is countered by moving or trimming the aileron.
This correction induces adverse yaw, which is corrected by moving or trimming the rudder (right rudder).
On aircraft with counter-rotating propellers (propellers that rotate in opposite directions) the torque from the two propellers cancel each other out, so that no compensation is needed.
 
P-Factor
P-factor is the term for asymmetric propeller loading, causes the airplane to yaw to the left when at high angles of attack.
The descending right side of the propeller (as seen from the rear) has a higher angle of attack than the upward-moving blade on the left side and provides more thrust. This occurs only when the propeller is not meeting the oncoming airflow head-on, for example when an aircraft is moving down the runway at a nose-high attitude (i.e. at a high angle of attack), as is the case with tail-draggers. Aircraft with tricycle landing gear maintain a level attitude on the takeoff roll run, so there is little P-factor during takeoff roll until lift off. In all cases, though, the effect is weaker than prop wash.
 
Gyroscopic Precession
This is the tendency of a spinning object to precess or move about its axis when disturbed by a force. The engine and propeller act as a big gyroscope. However, gyroscopic precession is likely to be minimal in a typical aircraft.
Gyroscopic precession is frequently confused with p-factor.
Title: Re: Prop wash
Post by: Saxman on December 10, 2013, 10:15:04 AM
You can't piecemeal realism in a game and expect it to work out.

And yet we have Friendly Collisions set to "Off."
Title: Re: Prop wash
Post by: Puma44 on December 10, 2013, 10:37:25 AM
And yet we have Friendly Collisions set to "Off."
Excellent point!
Title: Re: Prop wash
Post by: Puma44 on December 10, 2013, 10:42:34 AM
I think their ought to be prop wash as it changed combat sometimes. I remember this one story where a p51 was almost kicked inverted from prop wash at low speed when he was on a 109

Prop wash didn't change combat.  It was and is an integral part of flying that pilots have to be cognizant of and deal with, if encountered.  Most likely, the pilot stalled the Mustang and all the factors Traveler mentions below aided in the "snap", probably to the left.  Flying through prop wash won't necessarily cause a roll to the inverted.    :salute
Title: Re: Prop wash
Post by: FLS on December 10, 2013, 11:08:14 AM
I believe Olds is referring to a P-51 following a 109 that hit the 109's wake turbulence.
Title: Re: Prop wash
Post by: Arlo on December 10, 2013, 11:14:16 AM
You can't piecemeal realism in a game and expect it to work out.

And yet we have Friendly Collisions set to "Off."

That's not 'piecemeal' as much as a coded option that would
have have had negative consequence (due to the nature of its
limitations) had it been coded universally without the ability to
make it only active against opponents.

What I was responding to was a follow-up to a request to code
propwash into the game, which is probably a chore and a half in
itself, with an additional suggestion that it be coded at a certain
altitude or location. I don't think that even without making it more
complicated it would add enough to the game to warrant such effort.

My opinion, of course.

I get caught in the occasional inverted spins and stalls enough
as it is, anyway.  (Bearing in mind the current debate about
whether propwash is even that big a factor.) ;)
Title: Re: Prop wash
Post by: Traveler on December 10, 2013, 12:57:52 PM
I believe Olds is referring to a P-51 following a 109 that hit the 109's wake turbulence.
P51D was about 6 tons at take off, the 109 was around 3 tons, I doubt that wake turbulence was the issue.   The same reason there is no "caution wake turbulence" warning  for 747's departing after a 737.   Also Wake turbulence is at it's greatest when the aircraft generating it is in a slow dirty configuration, that Landing gear down, flaps and slow for landing or takeoff.
Title: Re: Prop wash
Post by: FLS on December 10, 2013, 01:16:29 PM
P51D was about 6 tons at take off, the 109 was around 3 tons, I doubt that wake turbulence was the issue.   The same reason there is no "caution wake turbulence" warning  for 747's departing after a 737.   Also Wake turbulence is at it's greatest when the aircraft generating it is in a slow dirty configuration, that Landing gear down, flaps and slow for landing or takeoff.


I believe that the wake could cause you to roll. I believe the pilot who reported it may have known what actually happened. 

I don't think we'll see it modeled for technical reasons but it would be cool.
Title: Re: Prop wash
Post by: Puma44 on December 10, 2013, 01:27:33 PM
I believe that the wake could cause you to roll. I believe the pilot who reported it may have known what actually happened. 

I don't think we'll see it modeled for technical reasons but it would be cool.

True, wake turbulence can cause some rolling motion.  Most times it is a manageable event countered with proper control input. Been there, done that.  The "kick to inverted" is more characteristic of an accelerated stall in the Mustang.  Been there, done that too.
Title: Re: Prop wash
Post by: colmbo on December 10, 2013, 06:08:46 PM
Prop wash did not cause the P51 to start to roll inverted.  Prop wash causes a yawing effect at low airspeed.  More likely it was Propeller torque effect which causes a rolling and is corrected with aileron controls

It was the prop wash off the 109 that caused the Mustang to roll.

You're correct in that your prop wash causes yaw….but rest assured the other guys prop wash will roll you.  (His wingtip vortices will also)
Title: Re: Prop wash
Post by: Ardy123 on December 13, 2013, 03:10:48 PM
Prop wash didn't change combat.  It was and is an integral part of flying that pilots have to be cognizant of and deal with, if encountered.  Most likely, the pilot stalled the Mustang and all the factors Traveler mentions below aided in the "snap", probably to the left.  Flying through prop wash won't necessarily cause a roll to the inverted.    :salute

Wouldn't it change the way people approached bombers? 
Title: Re: Prop wash
Post by: Puma44 on December 13, 2013, 03:38:37 PM
Wouldn't it change the way people approached bombers? 
More likely the defensive guns on bombers would change the way pilots approached them.
Title: Re: Prop wash
Post by: Ardy123 on December 13, 2013, 03:49:42 PM
More likely the defensive guns on bombers would change the way pilots approached them.

lol you would think... go into the MA... see how many players hug the back of bombers until their engines get smoked.
Title: Re: Prop wash
Post by: Puma44 on December 13, 2013, 03:58:50 PM
lol you would think... go into the MA... see how many players hug the back of bombers until their engines get smoked.
Oh, so true.....
Title: Re: Prop wash
Post by: guncrasher on December 13, 2013, 05:04:48 PM
lol you would think... go into the MA... see how many players hug the back of bombers until their engines get smoked.

sometimes you have no choice.  I'll climb over bombers till I get in a position of advantage.  but if I dont have the time and want to stop the bomber from dropping eggs, then it's tail time.  most of the time I die but also most of the time I disrupt the bomber from accurately dropping eggs.  lots of others do this also.


semp
Title: Re: Prop wash
Post by: Tinkles on December 13, 2013, 08:44:53 PM
sometimes you have no choice.  I'll climb over bombers till I get in a position of advantage.  but if I dont have the time and want to stop the bomber from dropping eggs, then it's tail time.  most of the time I die but also most of the time I disrupt the bomber from accurately dropping eggs.  lots of others do this also.


semp

That is sort of the point of being there is it not?  Killing the enemy or at least disabling them before they hit/reach their target? (Not attacking you, but agreeing with you.)

As long as I can distract them or kill some/all of them before they get to target, then that works for me.  Of course, killing all three bombers is even better :)
Title: Re: Prop wash
Post by: colmbo on December 13, 2013, 08:46:53 PM
Wouldn't it change the way people approached bombers? 

You can get very close without running into turbulence.  We eased up so our nose was within about 10 feet of the B-24 without any bumps, we were about 8-10 feet lower.  No picture up close because I put the camera down to work the throttles as the other guy flew.

(http://home.gci.net/~sncdfalk/bombpics/b24six.jpg)
Title: Re: Prop wash
Post by: Puma44 on December 13, 2013, 11:18:51 PM
Great picture and formation flying, Columbo! 
Title: Re: Prop wash
Post by: colmbo on December 14, 2013, 04:35:58 AM
Great picture and formation flying, Columbo! 

It's easier when you don't have to use a hat for views and your butt can tell you what the airplane is doing.
Title: Re: Prop wash
Post by: FLS on December 14, 2013, 04:55:10 AM
It's easier when you don't have to use a hat for views and your butt can tell you what the airplane is doing.

You're using a hat in your avatar.  :bolt:
Title: Re: Prop wash
Post by: Puma44 on December 14, 2013, 08:57:23 AM
It's easier when you don't have to use a hat for views and your butt can tell you what the airplane is doing.
Roger that!
Title: Re: Prop wash
Post by: captain1ma on December 14, 2013, 01:33:47 PM
nice picture of a old plane and a plastic bottle of poland springs on the dash!! LOL

great pictures anyway.

speaking of prop wash, all i can think of is inflight refueling. never seems to be a problem. <S>

PS as a boat captain, my prop wash come out the back of the boat, unless i send a new deckhand to find it!
Title: Re: Prop wash
Post by: earl1937 on December 14, 2013, 01:59:42 PM
It's easier when you don't have to use a hat for views and your butt can tell you what the airplane is doing.
:airplane: One of the hardest things for people to learn to do is ignore their body sensations when learning to fly on instruments in IFR weather. When you see a student, recovering from unusual attitudes, on the gauges, quickly recovering to straight and level flight, then you know he has mastered the art of mental discipline of trusting what the gauges are telling him and then you know he is on the way to becoming a instrument pilot.
Then comes that day or night when he has to punch through a area of "boomers". Now all of a sudden a whole new set of varables comes into play. What with ATC giving him vectors to help him through the mess, bumps, up drafts, down drafts, went from daylight to all of a sudden, very dark and had forgotten to turn on his instrument lighting system, thinks the lights had failed, trying to locate a flash light, can't stay within 500 feet of assigned altitude and knowing other aircraft are in the same general area, sweat running down into your eyes, can't see to good then and then you bust through into bright sun light and you are still right side up and a great sense of relief comes over you and then you know that you are truly the master of instrument flying!