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Control Surfaces


The first step in designing the ailerons is to decide which model of aileron we are going to use. The top three contenders are as follows:

Frise Type Ailerons:

These Ailerons would look very professional as they would be incorporated into the wing. They would reduce flutter because of aerodynamic balancing and would help reduce adverse Yaw. However, they might be difficult to manufacture and could cause some issues with the airfoil depending on how well we can build them. Also, we haven’t seen incorporated ailerons on a lot of LSAs or ultralights. Overall they would take less material (and thus weigh less) and would most likely not span as long as some other ailerons.

Junker Type Ailerons:

These ailerons are very effective because they have their own flow stream. However, we don’t necessarily need our ailerons to be very effective. Also these ailerons might also be difficult to manufacture bon’t won’t affect the performance of our overall wing no matter what. We have seen these on a number of LSAs and one ultralight. This would be the most heavy option.

Cheap&Easy Ailerons:

These ailerons are exceptionally easy to manufacture and we have seen them on a number of ultralights. They won’t affect our wing performance at all but they won’t be very effective either. This is okay because we don’t need our ailerons to be very effective. However, these ailerons won’t look very professional and they are kinda lame.

Personally, we think that Frise type Ailerons are the best option because they have the most useful benefits to the aircraft and they would look the sexyest. However we do not know how big of an issue adverse yaw or flutter will be in an aircraft of our caliber. If they aren’t too big of a deal than Cheap ailerons might just be what we do (although they aren’t very cool).

The next step in Aileron design is Aileron sizing. This depends on what aileron type we will be using so we will give some general guesses for each of the aileron types:

Frise type:

If we choose frise type ailerons they will most likely extend from 50% of wing span to 90% of wing span as that is standard for most incorporated ailerons (at least that’s what it says in Daniel P Raymer’s “Aircraft Design: A conceptual Approach). Also in this textbook is a graph that recommends the aileron extend about 22% of with the aforementioned dimensions.

Junker Type:

If we choose junker type (though unlikely), They will most likely span the entire wing span and extend about 15% chord. as that is what we see in most other LSAs w/ Junker type ailerons.

Cheap&Easy Ailerons:

If we choose cheap&easy ailerons they will also probably span the whole wing and extend about 15% of chord b/c that’s what we see in most ultralights.

Elevators & Rudder

After sizing the horizontal tail we looked at a bunch of other elevators and came to the conclusion that they frequently are simply half of the horizontal tail chord and the full span of the horizontal tail. We then moved the hingeline to 15% of the elevator chord in order to add an overhang. This is to incorporate aerodynamic balancing into the design which helps with flutter

I did research on the rudder and came to a similar conclusion as the elevators in which the rudder is about 50% of the vertical tail chord. However we left 15% of the height both above and below the rudder on the vertical tail for a spacer for the elevator and for ease of design. The spacing allows for an easier attached hinge-line.

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1 Comment

Marcel Bihan
Marcel Bihan
Dec 07, 2022

Wow man is everyone as smart as @MarkRoberts

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