Help! Is Polyhedral as effective as Dihedral

Noob777

Member
Is Polyhedral as effective as Dihedral if my Polyhedral is made just from one piece of flat foam board?
 

Noob777

Member
And will it be bad for aerodynamics if I put ailerons like that?
 

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quorneng

Master member
Noob777
The effect of dihedral primarily results from how far the wing tip is above the centre of the wing.
For a given amount of wing tip height polyhedral can give slightly more stability but the construction is more difficult and the extra joint can make the wing a bit weaker.
The issue with 'trailing edge' ailerons is the wing section at the aileron is disturbed. Whether the effect is noticeable will depend on the aerodynamic efficiency of the whole plane.
It would not be done like that on a high performance glider where every little helps but on an already aerodynamically inefficient power plane it would likely not even be noticeable.
 

Noob777

Member
Its just a folded depron sheet, with a wood spar . I tape the whole sheet on one side, mark my fold line on the other side, cut a V down to the tape so it becomes the leading edge and fold over, glue and tape. On this model I inbedded the servos in the wing before the fold.
what is the wing area and weight of your plane?
 

Diablito

New member
what is the wing area and weight of your plane?
Its about 120cm width, and about 23cm cord + ailerons, AUW is 500-550g, its very floaty👌 perfect trainer type plane. Very forgiving, it can stall and goes straight in to a glide.
IMG_20210513_162056.jpg
Here you can see the profile, i think the wooden spar is 10x10mm

This plane is a year old now, still going strong!
 

Noob777

Member
Its about 120cm width, and about 23cm cord + ailerons, AUW is 500-550g, its very floaty👌 perfect trainer type plane. Very forgiving, it can stall and goes straight in to a glide.
View attachment 200098
Here you can see the profile, i think the wooden spar is 10x10mm

This plane is a year old now, still going strong!
How did you get it so light?
 

quorneng

Master member
Noob777
Any given size of aileron produces a force when it is deflected. The further away that force is from the centre of the fuselage the harder the aileron will make the wing move. So unless there is some structural reason ailerons are normally positioned as far out on the wing as possible.