Flap/Elevator Mix on Warbirds: Automatically or Manually Activated
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Flap/Elevator Mix on Warbirds: Automatically or Manually Activated
I am moving up to 50cc Sized Warbirds which use and have Flaps; I understand that some times, not sure if that would be all the time; that when you apply the Flaps for landing, aircraft will want to balloon or climb; in this regard or event, you have to apply some down elevator; would it be good to just dial in or program in a Mix that some Down Elevator is automatically applied when you activate the Flaps; or should this Mix only be activated manually by a switch? the reason I ask, I am running out of ON/OFF Switches and if a Flap/Elevator Mix is needed, can it be automatically activated like I described or better if switch activated?
Thanks.
Thanks.
#2
Dasintex-
I have some large warbirds including a B-25, Corsair and Spitfire and all have active flaps. What I do is put my flaps on the slider on the side of my Futaba radios so that I can dial in the amount of flap I need for the wind conditions at the time. I never mix elevator and flap. I use the throttle to slow the plane while applying flaps to prevent ballooning. This is what works for me and each of my planes are set up to handle the same amount of flap as the full scale plane had. This is not the only method but it works for me. Hope it helps.
I have some large warbirds including a B-25, Corsair and Spitfire and all have active flaps. What I do is put my flaps on the slider on the side of my Futaba radios so that I can dial in the amount of flap I need for the wind conditions at the time. I never mix elevator and flap. I use the throttle to slow the plane while applying flaps to prevent ballooning. This is what works for me and each of my planes are set up to handle the same amount of flap as the full scale plane had. This is not the only method but it works for me. Hope it helps.
Last edited by tevans55; 06-27-2014 at 11:42 AM.
#4
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I would fly it with no elevator/flap mix unless the instructions tell you add it. If the instructions tell you to add a mix, and you want to add it, I would start with a little less than what is recommended, and try it. Many times, the nose gets pushed down with flaps, can't assume it will climb
You didn't mention what plane or what radio. This is an easy mix for most radios
You didn't mention what plane or what radio. This is an easy mix for most radios
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From the replys, I'm getting mixed opinions, I'd prefer to go the automatic activation route because it would free up a switch, and I would presume just adjust the mix to suite the individual planes habits.
Another quick question, I may have to ask Futaba; I use one of the Varible Rotating Dial Switches on the Side of the Radio to deploy the Flaps, this way I can deploy more or less flaps as needed; if I dial in a Mix that Activates some Elevator in the direction I need, can the amount of Elevator vary depending on how much flap is used; ie: If more Falp is deployed, proportional more Elevator is activated?
Thanks.
Last edited by dasintex; 06-27-2014 at 06:11 AM.
#6
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Ignore the ones telling you not to do it, you're simply using a feature of a fancy radio you paid for, that will make your pilot work load less so you can concentrate on flying.
Do do what I said, take it up, deploy the flaps, see what you need, start small and work your way up. 3 or 4 landings and you can have it dialed in.
I'm not sure about the Futaba but if you have the choice between a linear and curve mix, then the curve mix will let you set the amount of elevator at several points along the flap throw.
Personally, I'd set it on a 3 position switch. I've gone the slider route and unless i'm flying a competition glider where I want that n'th control of the glide slope for spot landing points, I just stick it on a switch; up - takeoff/approach - full flaps
Do do what I said, take it up, deploy the flaps, see what you need, start small and work your way up. 3 or 4 landings and you can have it dialed in.
I'm not sure about the Futaba but if you have the choice between a linear and curve mix, then the curve mix will let you set the amount of elevator at several points along the flap throw.
Personally, I'd set it on a 3 position switch. I've gone the slider route and unless i'm flying a competition glider where I want that n'th control of the glide slope for spot landing points, I just stick it on a switch; up - takeoff/approach - full flaps
#9
Imagine a Moderator telling you to ignore people offering up an option and following that option with the statement that their are other methods you can use. I usually ignore people that tell you to ignore people...but that's just the way I fly...there are other options and opinions.
Shame on you BH...poor self imagine perhaps?
Shame on you BH...poor self imagine perhaps?
#10
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He's being given advice not to set up elevator to flap mixing, and then being given advice by others saying to do it.
Then he's confused.
I stand by what I said, to ignore advice against using a mix for elevator compensation for flap deployment. I say that as a modeler because there is no good reason at all not to use a mix. It has nothing to do with being a moderator or my self image.
Also, this isn't the only thread where there replies against it though the duplicate thread got closed.
There's more than one way to accomplish anything in this hobby, I'm all for that.
Then he's confused.
I stand by what I said, to ignore advice against using a mix for elevator compensation for flap deployment. I say that as a modeler because there is no good reason at all not to use a mix. It has nothing to do with being a moderator or my self image.
Also, this isn't the only thread where there replies against it though the duplicate thread got closed.
There's more than one way to accomplish anything in this hobby, I'm all for that.
#11
My reason for using my methodology was that wind conditions allow you to dictate how much flap and throttle to use. Is that not a good reason? You are saying there is not good reason at all not to use a mix. I said that there is...am I not entitled to offer up an option without being told I should be ignored? I also indicated that there are other methods including yours. I was not offered that option by you. I was told to be ignored.
#12
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Modulating the flaps is one thing, but they should always need the same compensation, no?
Though I dont see a need for that on most fixed wing planes, I'm not putting the practice of using the flaps on a slider.
I just maintain that there's no reason not to use a mix to compensate for ballooning. I'll also point out that you were specifically the advice I was saying to ignore
Though I dont see a need for that on most fixed wing planes, I'm not putting the practice of using the flaps on a slider.
I just maintain that there's no reason not to use a mix to compensate for ballooning. I'll also point out that you were specifically the advice I was saying to ignore
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The variable mix rate applies to whatever is mixed. If you mix flaps to elevator then you set the variable mix to change how much the flaps mix. That way you can set up a ton of flap but turn a knob so you only get a small amount of it with elevator. Once you decide how much flap you like you can make it permanent with the mix and stop messing with the variable rate if you wish.
#15
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Depends on the plane, but in general. I prefer to mix the elevator to the flap. Usually i start with about 10% down elevator at full flap. Most planes end up with about 15% down mixed in. I use a slider for the flaps. On my carf spitfire i don't use the flaps at all. It slows nicely without the flaps and it climbs sharply with partial flap deployment. You need a weird mix with it and it wasn't worth the hassle. At 50% flap it will nearly loop. At 100% flap it will drop like a rock and stay level. Fly your plane and feel it out at a safe altitude. Depending on wingloading, cg, your flying style you may not want to deploy them at all.
Last edited by 2walla; 06-27-2014 at 03:33 PM.
#16
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Appreciate all the replys, didn't mean to open a can of worms!
All I was trying to determine was if Flap Elevator Mix is a must, and if so, can it be an automatic mix when flaps are deployed to save using a Switch; so I think the best and prudent thing would be to fly it first, put on the flaps at altitude and see what it does and like someone said see if a mix is needed or not.
All I was trying to determine was if Flap Elevator Mix is a must, and if so, can it be an automatic mix when flaps are deployed to save using a Switch; so I think the best and prudent thing would be to fly it first, put on the flaps at altitude and see what it does and like someone said see if a mix is needed or not.
#17
Good Luck Dasintex, my intent was not to open a can of worms either. Also you may want to read up on flap deployment on full scale aircraft and its relationship to engine speed and wind/crosswind. That may help you understand my methodology.
#18
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[QUOTE=BarracudaHockey;11831138]Modulating the flaps is one thing, but they should always need the same compensation, no?
Not in my experience. I have the flaps on all my planes on a 3 positon switch with a 1-2 sec delay. Downwind leg one click of flaps req's pushing nose down. Plane slows 2nd postion flaps , some planes the nose will push over, some will climb a little. On final approach all are neutral, or a little up elevator. Depends of type and size of flap, and wing shape.
If I mixed in nose down to keep it from balloning, by the time its on final, I'm having to override the mix to hold the nose up.
To each there own, whatever works for you
Not in my experience. I have the flaps on all my planes on a 3 positon switch with a 1-2 sec delay. Downwind leg one click of flaps req's pushing nose down. Plane slows 2nd postion flaps , some planes the nose will push over, some will climb a little. On final approach all are neutral, or a little up elevator. Depends of type and size of flap, and wing shape.
If I mixed in nose down to keep it from balloning, by the time its on final, I'm having to override the mix to hold the nose up.
To each there own, whatever works for you
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Futaba 10C
From the replys, I'm getting mixed opinions, I'd prefer to go the automatic activation route because it would free up a switch, and I would presume just adjust the mix to suite the individual planes habits.
Another quick question, I may have to ask Futaba; I use one of the Varible Rotating Dial Switches on the Side of the Radio to deploy the Flaps, this way I can deploy more or less flaps as needed; if I dial in a Mix that Activates some Elevator in the direction I need, can the amount of Elevator vary depending on how much flap is used; ie: If more Falp is deployed, proportional more Elevator is activated?
Thanks.
From the replys, I'm getting mixed opinions, I'd prefer to go the automatic activation route because it would free up a switch, and I would presume just adjust the mix to suite the individual planes habits.
Another quick question, I may have to ask Futaba; I use one of the Varible Rotating Dial Switches on the Side of the Radio to deploy the Flaps, this way I can deploy more or less flaps as needed; if I dial in a Mix that Activates some Elevator in the direction I need, can the amount of Elevator vary depending on how much flap is used; ie: If more Falp is deployed, proportional more Elevator is activated?
Thanks.
Last edited by rrembert; 06-27-2014 at 07:50 PM. Reason: Wrong selection
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Modulating the flaps is one thing, but they should always need the same compensation, no?
Though I dont see a need for that on most fixed wing planes, I'm not putting the practice of using the flaps on a slider.
I just maintain that there's no reason not to use a mix to compensate for ballooning. I'll also point out that you were specifically the advice I was saying to ignore
Though I dont see a need for that on most fixed wing planes, I'm not putting the practice of using the flaps on a slider.
I just maintain that there's no reason not to use a mix to compensate for ballooning. I'll also point out that you were specifically the advice I was saying to ignore
#21
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Procedures, procedures, procedures.... You have to follow them for any model type because all planes behave differently and once you get into heavier planes with flaps its more important to understand that aircraft and its characteristics.
Ballooning is the result of over speed while in a configuration using flaps and a set elevator trim. When this happens simply slow down to maintain a certain altitude. Watch for ballooning at all times while the flaps are deployed as a tell tale of your speed. Don't add down elevator as this can put you into a PIO or pilot induced oscillation situation. Just slow down slightly and maintain your altitude. This is when you transition your piloting to controlling the rate of descent with power and less with elevator.
As the wind changes from one flight to another this will be an important clue as to what flap position to use and what to do. You can save your plane and a lot of grief if you pay close attention to this behavior. Too much flap can be a bad thing as well as too little so the wind condition is what I use to determine the flap position, if needed at all, to land.
Power management is key when in a flap config ready to land. Dive bombing the runway on final is the wrong way to approach a landing. That way will cause ballooning on final. The right way to go is using power and finding the right balance of rate of descent and airspeed to land. You have to get comfortable with slow flight and high angles of attack. Spend a lot of time high up in the air flying slow with and without flaps and playing with the power. Fly into the wind and deploy flaps to see what happens when you over speed the plane and it balloons into a head wind. Perform stalls using flaps too. All of this just adds to your pilot skills and knowledge of your plane in adverse conditions.
Elevator trim with flaps deployed depends on the plane and its characteristics. Some require no compensation others do.
Mixing flap trim, which I do, with the radio is great once you establish what the particular plane does when the flaps are deployed. The method I use is simple. Fly w/o mixing and do it by hand while adding flight trim until the planes attitude is satisfactory. Then land and review the percentage you had to add with that flap setting. Now copy that back into your mix as your flap mix percentage. Try it again and check to see that the plane flies as it did before but now with the flight trim at its usual if not zero position.
Depending on your radio you can set the individual flap and elevator mix at PO1 and PO2.
Slowing the flap servos is both cool looking and helps prolong the change in the flight characteristic of the plane so you know what to expect. If the flaps simply pop out then the plane will simply react and you will be behind the plane mentally. For a scale plane thats a bad position to be in so slower flaps are a good thing I think. I use one second typically.
Back to procedures... learn the planes history and how the plane was flown. Read the flight manual, watch videos of both full scale and others models and see what the type typically does and how to handle it. This is mental prep for you to file away in your mind.
Personally I try to emulate the full scale procedures because many have gone before me and made the plane work a certain way and thats just how they work, by the book. Models will give you a broader envelope than full scale for the most part but the basic DNA is there so its best to understand that.
Good luck, post pics of your warbird
Ballooning is the result of over speed while in a configuration using flaps and a set elevator trim. When this happens simply slow down to maintain a certain altitude. Watch for ballooning at all times while the flaps are deployed as a tell tale of your speed. Don't add down elevator as this can put you into a PIO or pilot induced oscillation situation. Just slow down slightly and maintain your altitude. This is when you transition your piloting to controlling the rate of descent with power and less with elevator.
As the wind changes from one flight to another this will be an important clue as to what flap position to use and what to do. You can save your plane and a lot of grief if you pay close attention to this behavior. Too much flap can be a bad thing as well as too little so the wind condition is what I use to determine the flap position, if needed at all, to land.
Power management is key when in a flap config ready to land. Dive bombing the runway on final is the wrong way to approach a landing. That way will cause ballooning on final. The right way to go is using power and finding the right balance of rate of descent and airspeed to land. You have to get comfortable with slow flight and high angles of attack. Spend a lot of time high up in the air flying slow with and without flaps and playing with the power. Fly into the wind and deploy flaps to see what happens when you over speed the plane and it balloons into a head wind. Perform stalls using flaps too. All of this just adds to your pilot skills and knowledge of your plane in adverse conditions.
Elevator trim with flaps deployed depends on the plane and its characteristics. Some require no compensation others do.
Mixing flap trim, which I do, with the radio is great once you establish what the particular plane does when the flaps are deployed. The method I use is simple. Fly w/o mixing and do it by hand while adding flight trim until the planes attitude is satisfactory. Then land and review the percentage you had to add with that flap setting. Now copy that back into your mix as your flap mix percentage. Try it again and check to see that the plane flies as it did before but now with the flight trim at its usual if not zero position.
Depending on your radio you can set the individual flap and elevator mix at PO1 and PO2.
Slowing the flap servos is both cool looking and helps prolong the change in the flight characteristic of the plane so you know what to expect. If the flaps simply pop out then the plane will simply react and you will be behind the plane mentally. For a scale plane thats a bad position to be in so slower flaps are a good thing I think. I use one second typically.
Back to procedures... learn the planes history and how the plane was flown. Read the flight manual, watch videos of both full scale and others models and see what the type typically does and how to handle it. This is mental prep for you to file away in your mind.
Personally I try to emulate the full scale procedures because many have gone before me and made the plane work a certain way and thats just how they work, by the book. Models will give you a broader envelope than full scale for the most part but the basic DNA is there so its best to understand that.
Good luck, post pics of your warbird
#22
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I always mix flap and elevator. First I eyeball it then make corrections after flight. It's a nice feature and honestly Jeff Folly set up my Chipmunk. And it lands like a dream. Mixed flap and elevator. Hmmm wonder how many warbirds Jeff has ?
#23
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You don't need a elevator/flap mix if your transmitter offers a servo speed adjustment. Just slow down the speed of the servos' extension/retraction and diving/climbing will be eliminated almost entirely. It is all about reestablishing the boundary layer and the best way is too do it slowly.
Last edited by flycatch; 06-28-2014 at 05:56 PM. Reason: More Information
#24
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On the test flight I have the flap-to-elevator mix screen displayed and a trusted helper to assist in getting the settings right. At high altitude with the flaps and gear down, I add enough down elevator to the mix to hold level flight at about 25 percent power. Below that, it descends with a nose down attitude that prevents stall. At 25 percent power it chugs along until I am ready for it to land (by reducing power). Above that, it climbs.
I set both the flaps and elevator mix to run at 25 percent of normal speed.
I study a lot of flight videos that show a flapped warbird on a roller coaster ride when landing. If timed well, these oscillations can lead to a good landing. If not, they seem to lead to a stall and crash. With the setup I use, I decide when it comes down by jockeying the power, and the down elevator prevents the roller coaster/ballooning that makes for very dicey landings.
Watch at 1:48 http://www.youtube.com/watch?v=Dd0YoC5OKwI
Watch at 1:58 http://www.youtube.com/watch?v=ZzPiCEolZ8s
I learned the process through trial and error, and the system described works very well for me.
I set both the flaps and elevator mix to run at 25 percent of normal speed.
I study a lot of flight videos that show a flapped warbird on a roller coaster ride when landing. If timed well, these oscillations can lead to a good landing. If not, they seem to lead to a stall and crash. With the setup I use, I decide when it comes down by jockeying the power, and the down elevator prevents the roller coaster/ballooning that makes for very dicey landings.
Watch at 1:48 http://www.youtube.com/watch?v=Dd0YoC5OKwI
Watch at 1:58 http://www.youtube.com/watch?v=ZzPiCEolZ8s
I learned the process through trial and error, and the system described works very well for me.
Last edited by Lifer; 06-28-2014 at 01:10 PM.
#25
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If your methodology was used in full scale of Not applying elevator compensation with flap deployment, we would be seeing A lot of landing incidents where the nose gear was shoved through the structure of the airframe, especially on higher performance aircraft.
Full scale guys always compensate for pitch changes due to flap position changes by adjusting the elevator trim. This is essentially a manual "elevator to flap mix" done by the pilot to relieve control forces, it also helps make the flare a little bit easier to do as well.
With a model we done have the priviledge to "feel" the control force changes due to airspeed or an airspeed indicator. But we do have he priviledge of fancy computer radios and mixes to help make our lives easier.
What i personally do, is take a new model up high and fly it around at minimum controllable speeds to determine its stall characteristics and i repeat this with varying flap deployments (i use a three position switch, UP, Takeoff flaps and Landing flaps). Takeoff flaps are typically around 15* and landing flaps per the full scale or 50-60*. This initial flight has 10% of Down elevator deflection mixed in with full flaps.
During the initial flights with flying at low speeds you want to determine the stall speed with the flaps in all positions as this is the basis of your elevator to flap mix adjustments. Once you know where it will stall with the flaps in the takeoff position, do a level pass at a speed slightly higher than stall and adjust your elevator percentage so the airplane maintains level flight or a very Slight descent. Now repeat the process for full flaps.
Once you have that setup, a certain power setting and flap position will provide Exactly the same results every time! If you are slower than your approach speed, the airplane will descend quicker than normal, if you are fast, it will stay level or climb.
This method works on anything and provides the platform for the most stable approach setup you can get, the best part of all is it is Repeatable!