Eagler's Nest
Airframes => Double Seaters => DE => Topic started by: DErwin on May 10, 2018, 01:20:23 AM
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Hi and good day to all.
Finally back in building my DE. I will be fitting the wings to the fuse and attaching the front and rear spars to the wings.
I can not seem to find in the plans the required dihedral for the wings. Can someone please help me out.
Thanks and I hope some one can help me on this soon.
Happy building
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3in i set mine i think, i dont think its in the drawings
if you dont get an answer ill measure up tomorrow
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Hi MrG,
Thanks for the reply. I just want to clarify,
You mean to tilt up the wing tip by 3-inches from level?
Thanks again
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Yes Ill get back to you on measurement in about 3 hrs
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Hi MrG,
Were you able to get the measurements. Sorry to rush up on you.
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No Friday was a bad day
in morning is sat ill do then i dont have to go any were its only in next doors hanger
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3" higher than level at the wing tips is the measure for the cabin eagle. I presume the DE would be the same.
...Paul
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Paul,
Thank you so much for the confirmation on the 3'' dihedral.
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Yes correct
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So it is definitely three(3) inches up on the wing tip from level for the dihedral .
Thank you so much for the response and clarification.
Thanks MrG and Paul. Will send a picture of the set-up later.
Cheers and blue skies to all.
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to be honest after all the mods ive done to mine and flying 120 hrs on it, i would doubt even if you were a inch out up or down you would
not notice the difference - the main thing is the wash out in the wing makes a big dif. how it stalls
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Yes I agree with you MrG.
I am planing to set the wash-out as suggested on the video by Leonard. The wing root is set at a positive angle
2-Degrees incidence as per plan on the DE. The wing tip is set level with the horizontal of the fuselage.
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To all:
On a DE, is wing dihedral really necessary?
Do you guys think it (dihedral) makes a measurable difference in handling?
Cheers,
Azevedoflyer
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Aze, I have had the same thought. Our DE Stubby has the dihedral as per plans. I suspect that no dihedral would not make a significant difference in handling, but it might result in a bit more speed. These aircraft are relatively light, and even light breezes can lift a wing, requiring the pilot to actively fly the plane, and I don't feel that the dihedral provides much stability.
Only my thoughts based on our DE, mind you.
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Wing dihedral is one of the primary factors affecting roll stability.
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Have any of you operated a skid steer machine like a "bobcat" as an amateur. How did you like that forward and back oscillation. Let go and grab the cage is the answer then learn to be a little smoother on inputs until you get it down, I can see the possibility of roll oscillation without dihedral. Gyrocopters can get a pitch oscillation that can build to fatal. Too bad you may have to cut your struts to find out
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The Cessna 195 and the Wittman Tailwinds have no dihedral and are both very stable aircraft. However, they are not light wing loading craft, so who knows?
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Wing dihedral is one of the primary factors affecting roll stability.
Not to put too fine a point on it but dihedral effect is one of the primary factors affecting roll stability not to be confused with dihedral angle.
A high wing airplane has plenty of dihedral effect due to the weight being below the wing irregardless of dihedral angle. It imparts a pendulum effect, think paraglider/powered parachute.
A notorious Tailwind builder (builder of 12 Tailwinds) adds 3/4" of dihedral on a 24' span even though the plans call for zero. He does this so the wings do not look like they droop (anhedral).
The last thing I want in a light plane is to invite a gust getting under a wing with dihedral it does not need on short final in a crosswind putting me in a big dutch roll.
If you only ever fly in absolute nil wind and don't need the lift you would give up, you could put as much in as a 2 axis design perhaps. Most 2 axis ultralights I have seen have more span.
Just my (strongly held) opinion. https://en.wikipedia.org/wiki/Dihedral_(aeronautics) (https://en.wikipedia.org/wiki/Dihedral_(aeronautics))
:emoji_u1f62f:
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Well, 3" at the tip of a 168" wing (per DE Left wing drawing / 3" tilt is listed) boils down to a measly 1 deg. dihedral per side.
The restoring rolling moment will be 1.8% of the lift generated. At a DE AUW of 900 lbf, that equates to 16 lbf.
Did not calculate but I suspect that the pendulum effect of engine, fuselage and pilot weight - forget fuse drag for the moment - will be more relevant.
Mr. DErwin, as said above, look at left wing drawing and in the text below it is stated dihedral to be provided by a 3" tilt upwards.
Cheers,
azevedoflyer😎