Flaps or flaperons

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Macthenife33

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Lets say you were going to build a light sport aircraft and i mean light . And your purpose was strictly back country bush flying . Hunting , hauling moose meat . Real STOL FLYING . Ive lived in ALASKA all my life and hunted in some real remote places . . My question is reguardingwing structure ailerons , and flaps or flatirons? oh and i forgot to mention first time builder so simplicity goes a long way .wich would suit my purpose better
 

Victor Bravo

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Regular flaps and separate ailerons will give you better low-speed safety and handling. This is only slightly more effort than one-piece flaperons (Avid/ Kotfox, Zenair, etc.) but the low speed safety is a big deal in real back country flying.
 

TFF

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You live where the experts are. What are they saying? I have a friend with a fancy Cub that can fly some weigh, but it is not LSA by a long stretch

If you want to pull a moose out, you will probably need more airplane. Light sport max weight, airplane, fuel, people, cargo, is the weight of a moose if not less.

There is some cool stuff out there, but put pencil to paper and be realistic. How much weight, how much fuel, how much you weigh with your stuff. Moose are not unicorns.

You haven’t even talked budget.
 

Victor Bravo

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How many trips back and forth are you willing to make before the entire moose is moved to where it needs to be? One trip... two trips... four trips? That right there will be a prime factor i n your airplane choice and how much you have to spend.

As far as your original question, separate flaps and ailerons PLUS a well designed control mixer will give you the best of both worlds. Not a whole lot of airplanes have this, but as someone who has flown one of the few airplanes that had this capability... I can say it's magic :)
 

Hot Wings

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As far as your original question, separate flaps and ailerons PLUS a well designed control mixer will give you the best of both worlds.
I'll second that. The mixer can be pretty simple. Take a look at the one used in the Q-2/200. They use it backwards and call it a 'reflexor', but the idea is the same.
 

pylon500

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Have a look at the flap and droop aileron system on a DHC Beaver.
(Despite the number of years I worked on them, it appears I never took a photo of the aileron mixer!)
 

Hot Wings

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No, I'm talking about a real well engineered mixer, not a reflector.
Other than a bit of asymmetry with at least one* of the Q-2/200 reflexor versions how are they any different than any other mixer? V-tail mixers, flying wing aileron/elevator mixers, brake rudder mixers and even what I though you were proposing, ailerons that droop in proportion to the flap setting, are all functionally the same thing?

*I agree that there are some Rube Goldberg systems out there. Others are quite elegant.
 

Victor Bravo

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I'm referring to the control mixers on the better sailplanes, where you had full span differential/progressive aileron using the stick, full span camber changing using the flap lever (flying range), and then when you pulled the flap lever back past a gate (into the landing range) it went into "crow" position where the flaps came down 55 degrees and the ailerons reflexed upward 6 degrees.

I'm not kidding, it's absolute magic mechanically and what it allows you to do with the airplane. The control mixer is nothing short of a master's thesis in mechanical engineering.

The standard Moni/Sonex V-tail mixers and the reflexor stuff on the Quickie is not even in the same universe. It didn't need to be in the same universe, there was no need for it on simple point A to point B airplanes.

THANK YOU for the mixer on the AS-W20 Dipl. Ing. Gerhard Waibel !!!! :bow::bow::bow:
 
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Victor Bravo

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Landing a 700 pound glider, with no go-around possible, on a Marine Corps Mountain Warfare Training Center high altitude helicopter pad, in the Sierra Nevada, at 10K+ density altitude, because you're lost and stupid and were trying to win a contest instead of flying safely.

Being able to roll an unpowered aircraft away from the side of a mountain, 5% over stall speed, in turbulence and wind gusts that equaled the flying speed of the aircraft, at a >12K density altitude... with 40 gallons of water sloshing inside the wing... and having an aircraft that will do that and then have an emergency safety "out" by deploying the landing flaps and un-stalling the wingtip that you stalled on the mountain side of the aircraft.

There are a few other people here who have flown that model of sailplane, and I will bet hands down that they will tell you the same thing... it's a magic airplane, and the primary reason is that mixer. Again on many many airplanes it is a moot point, but in some situations it can just create an amazing capability.

The only part of this rant that is relevant to the kind of small powered aircraft we discuss here is that the "crow" function of a flaperon mixer can add a lot of safety for a very light airplane at low speeds in gusty air.

USMC Training Center Bridgeport.jpg
 
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Riggerrob

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A the other end of the complexity scale, a Russian discoplane only used cables to operate a pair of elevons. Rudder cables were separate from the "mixing" mechanism.
 

Riggerrob

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OP, the primary reason for all drooped outer leading edges, slats, slots, vortex generators, wing twist, etc. is to reduce the angle of attack of the outboard wing (aileron territory) so that outer wing panels retain smooth airflow after the center section is stalled. This helps maintain roll control (ailerons) effective part way into the stall.
Note that STOL bush planes like DHC-2 Beaver never droop ailerons as far as (inboard) flaps.
 

WWhunter

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Take a look at the Kitfox of Murphy Rebel. While the Rebel can be built with split flaps/ailerons, the majority of them are built with flapperons.
Both aircraft type fly great with flapperons. I have flown in both types. Currently flying a Rebel and its a pretty stable aircraft with great performance.
 

REVAN

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Flaperons are a big step down compared to separate flaps and ailerons. This is especially true if you are building a constant-chord wing with no twist. When flaps are deployed, this creates an aerodynamic twist in the wing which greatly improves the handling and safety of the wing at low speeds. Flaperons trade all that in for a bunch of adverse yaw and a wing that is more likely to send you into a spin. It is a double lose design compromise that, in my opinion, is generally not worth the small parts count reduction that comes with flaperons.
 

Riggerrob

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Dear Revan,
From the opposite perspective, ailerons that droop with flaps provide a shallower angle of attack for the outer wing panels. Most of those STOL planes don't droop ailerons as deep as flaps. For example, flaps might droop 40 degrees while ailerons only droop 30 degrees. This means that outer wing panels stall later/steeper angle of attack and you maintain aileron control part way into the stall.
 

ToddK

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Why not just invent smart flaps that using sensors and a control box can augment each phase of flight either automatically, or upon pilot command.
 
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