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Old Feb 02, 2013, 07:14 AM
JKasprak
propchief's Avatar
Fayetteville, NC 28304
Joined Jan 2010
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Both wings have to be stalled and although you can use the rudder to keep them on line to the flight path the AOA is going to control the stall. Most wing rock occurs because the AOA is too shallow. Best way to eliminate wing rock is to get the AOA correct to stall both wings.
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Old Feb 02, 2013, 08:46 AM
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santa cruz ca
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Originally Posted by rimaarts View Post
my guess is around 4.30-5min... im running 3600 and after 6min come down at around 3.85 per cell...
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Originally Posted by bryansifsof44 View Post
I get about 5:30- 6 mins depends how I fly. I monitor volts via telemetry, so I land when I am out of gas. If I didn't have telemetry I would be a little more conservative.
Thanks guys.
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Old Feb 02, 2013, 08:48 AM
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Burke, VA
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The thing to remember about how the rudder helps stabilize the plane in harrier is due to how it's in the airstream. If the aoa is such that the fuse is at an angle that blocks the airflow over the rudder/vert stab then it neutralizes the effect the rudder has on eliminating too much yaw. So a lower aoa can keep the airflow making contact with the rudder, or a higher aoa will lower the rudder to the point where the wings are not blocking the airflow once again allowing the rudder to have an effect on yaw. But there is an in between angle where the rudder is completely blocked and the plane can yaw inducing the wing rock. So a high enough aoa to completely stall the wing and allow airflow to make contact with the rudder is the sweet spot for harriers. That's why you can feel it lock in when it hits this sweet spot. This is also why inverted harriers generally don't have the wing rock problem because with the rudder pointed down it's not blocked from the airflow thus helping to stabilize the tendency to yaw. At least this is the way I understand it, I may be mistaken and if someone can offer a better explanation I would appreciate it for a better understanding.
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Old Feb 02, 2013, 08:51 AM
Not as Good as The Kid
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South Pasadena, FL
Joined Sep 2009
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Originally Posted by propchief View Post
Both wings have to be stalled and although you can use the rudder to keep them on line to the flight path the AOA is going to control the stall. Most wing rock occurs because the AOA is too shallow. Best way to eliminate wing rock is to get the AOA correct to stall both wings.
And with a little more breeze than usual, it is always a little harder to keep the AOA correct upwind without good throttle management and elevator control.
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Old Feb 02, 2013, 01:29 PM
They Call him Dead!
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United States, SC, Pawleys Island
Joined Jul 2003
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I understand theoretically how inverted harrier should be easier. But I find that if I try to get a high AOA inverted to truly stall the wings, then the plane is at extreme risk of snapping on a dime and implementing disaster.

I find upright harrier much easier for this reason, but I do not understand why.
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Old Feb 02, 2013, 01:54 PM
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United States, AK, Anchorage
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For me it's more stable inverted... However high AOA inverted sometimes requires heavy rudder correction that may be more natural upright. I think one reason inverted is more stable it that there is more rudder in the air not being behind the wings... it is down there where there is nothing but free air. Where as upright there is usually some influence by the wings.

EDIT: LOL... I just read jets post above and we kinda went into the same thing.
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Old Feb 02, 2013, 07:02 PM
Not as Good as The Kid
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South Pasadena, FL
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Originally Posted by bryansifsof44 View Post
EDIT: LOL... I just read jets post above and we kinda went into the same thing.
Right, but there are two vectors at work here.

In full stall, and low speeds, with little wind, the vectored thrust from the prop is never, or nearly never, affected by the AoA. Throttle control and a nice size air disk from the motor will provide all the input the rudder and elevator will need, regardless of the AoA since the reference between the elevator, rudder, and the motor, don't change.

When flying upwind in breezy weather, a little more throttle and elevator control is needed to counteract the second vector, so input will change.
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Old Feb 02, 2013, 07:59 PM
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United States, AK, Anchorage
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Originally Posted by Aeroplayin View Post
Right, but there are two vectors at work here.

In full stall, and low speeds, with little wind, the vectored thrust from the prop is never, or nearly never, affected by the AoA. Throttle control and a nice size air disk from the motor will provide all the input the rudder and elevator will need, regardless of the AoA since the reference between the elevator, rudder, and the motor, don't change.

When flying upwind in breezy weather, a little more throttle and elevator control is needed to counteract the second vector, so input will change.
True and thats why we like the big disks.

I was talking about harrier flight with some forward movement in calm conditions. However I would say AOA influences vectored thrusts effect for one reason... lower angles in level flight require more forward speed therefore changing the way the air from the prop goes over the surfaces. All theories aside... higher AOA inverted or normal require more rudder input.
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Old Feb 02, 2013, 09:26 PM
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Orlando, FL
Joined May 2010
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AOA has a negligible impact to the propwash/airflow. Throttle is proportional to volume of flow- as throttle goes up, volume of airflow over the surface goes up. AOA has almost no effect on that relationship, except in extremely high energy maneuvers- and then only momentarily.

The same goes for wind, I believe.
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Old Feb 02, 2013, 10:26 PM
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United States, AK, Anchorage
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I don't claim to be a expert in the science of airflow... I just fly the darn thing. I do know that you need more throttle (vectored thrust) to make the plane do what you want it to do at higher AOA. Most likely from the decrease airflow from the air going by. In other words... You need a little throttle for the control surfaces to have adequate influence.
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Old Feb 02, 2013, 11:40 PM
Video Juggernaut
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FL
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It was very windy today. as far as harriers go, all my new learned skills went the drain. Down wind is cool but the wind pushes you so fast it loses the effect of the harrier. I can keep the aka but it zips down the road. Then into the wind is tough, always wants to go level. I hate FL east coast wind!
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Old Feb 03, 2013, 07:34 AM
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Burke, VA
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Originally Posted by Luv3d View Post
AOA has a negligible impact to the propwash/airflow. Throttle is proportional to volume of flow- as throttle goes up, volume of airflow over the surface goes up. AOA has almost no effect on that relationship, except in extremely high energy maneuvers- and then only momentarily.

The same goes for wind, I believe.
Actually the aoa has the most impact depending on wind, the higher the aoa the more wing area exposed to the wind and the more lift due to more force. Remember as a kid holding your hand out the window of the car, holding your hand level had very little effect, but change the aoa and it has a lot of effect. As far as prop wash, it also will be affected by the wind. Going against the wind you add the wind speed to the prop wash so need less throttle for the same amount of air moving across the surface of the plane, plus the added lift generated by the wind depending on aoa. And the opposite is true going with the wind, requires a lot more throttle to maintain a harrier and the harrier is going to be at a higher speed due to loss of lift. All these forces together have an impact on a plane no matter what attitude it's in.
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Old Feb 03, 2013, 11:40 AM
Video Juggernaut
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Originally Posted by jetinteriorguy View Post
Actually the aoa has the most impact depending on wind, the higher the aoa the more wing area exposed to the wind and the more lift due to more force. Remember as a kid holding your hand out the window of the car, holding your hand level had very little effect, but change the aoa and it has a lot of effect. As far as prop wash, it also will be affected by the wind. Going against the wind you add the wind speed to the prop wash so need less throttle for the same amount of air moving across the surface of the plane, plus the added lift generated by the wind depending on aoa. And the opposite is true going with the wind, requires a lot more throttle to maintain a harrier and the harrier is going to be at a higher speed due to loss of lift. All these forces together have an impact on a plane no matter what attitude it's in.
I hate wind
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Old Feb 03, 2013, 11:50 AM
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Burke, VA
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I hate wind
Ahh, but wind can be a lot of fun once you get used to it. You just have to approach things differently. The big trick is landing if it's too gusty. Foamies in the wind are a blast and the landings aren't as worrisome. Flying directly into the wind if it's steady is actually really good practice for harriers, try holding it in one spot while in harrier mode. This will really help with getting the feel for it. Elevator landings are especially fun, depending on how much wind you can almost do a vertical drop into a landing. The Edge is particularly good at this, when I first got mine I loved doing them in about 10-15 mph breeze.
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Old Feb 03, 2013, 12:32 PM
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Originally Posted by jetinteriorguy View Post
Ahh, but wind can be a lot of fun once you get used to it. You just have to approach things differently. The big trick is landing if it's too gusty. Foamies in the wind are a blast and the landings aren't as worrisome. Flying directly into the wind if it's steady is actually really good practice for harriers, try holding it in one spot while in harrier mode. This will really help with getting the feel for it. Elevator landings are especially fun, depending on how much wind you can almost do a vertical drop into a landing. The Edge is particularly good at this, when I first got mine I loved doing them in about 10-15 mph breeze.
steady wind is fun! gusty wind is unhealthy for my pants and plane if attempting down low stuff....
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