Aerodynamics Discuss the physics of flight revolving around the aerodynamics and design of aircraft.

Dihedral

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Old 03-26-2018, 10:58 AM
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whatnext
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I am building an old Bridi Krafty.The wing is semi- symmetrical. It calls for 1" 1/4 under each wing tip..I woke up one morning and glued the wing halves together. Apparently was still asleep because I ended up with "2 1/2 of dihedral under each wing tip. It comes with a pre cut wedge that glues in place that determines the amount of dihedral. It comes pre cut but I should have sanded it down to get get the proper amount of dihedral. The center section is not fiberglassed yet. What aerodynamic effects will too much dihedral have on the flying characteristics of this type of model .It will have a KB 61 on it so it will not be slow.
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Old 03-26-2018, 11:49 AM
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All Day Dan
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2.5 inches for a 31 inch wing panel is a little less than 5 degrees. All my planes have five degrees dihedral in them and they fly fine. Dan.
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Old 03-26-2018, 04:08 PM
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whatnext
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I've talked to a few of the vintage pattern fliers and they are saying it won't turn very well with ailerons. That it will most probably need rudder mixed with ailerons..
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Old 03-27-2018, 05:52 AM
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i'll bet what they are trying to say is,.."you most likely will not even need aileron to turn...... it should turn pretty good on rudder alone". actually easier to fly.
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Old 03-28-2018, 02:04 PM
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A high wing plane even without any dihedral at all will have a dihedral effect. I agree that yours will probably turn quite well on rudder alone. I also agree with the pattern fliers, that aileron-rudder mixing would be a good idea. I have done that on many of my planes and like it. When you are flying slow, adverse yaw is more pronounced than at higher speed, so coupling does not give you automatically coordinated turns at all times, but it works well enough. You can always add more rudder with the stick.

If you are past the training stage I would take out the dihedral. In fact, I would take all of it out. But if you are a beginner, you can leave it in. Later you can cut the wing and re-glass if you want.

Jim
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Old 08-05-2018, 07:07 AM
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with that much dihedral, you probably won't need aileron for anything but landing approach and rolls. knife edge will be OK , but inverted flight might be a bit unstable. when inverted, the plane will want to right itself automatically and it might behave like it is balancing on a ball, wanting to flip back over at the slightest suggestion. center of drag to center of thrust will be higher, so it will also want to climb on throttle application a bit more...... you might have to watch it a little closer than if it had it's normal or no dihedral.
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Old 11-24-2018, 11:12 AM
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Im wondering what the OP did here. I would have cut the wing apart and put back together with the correct dihedral.
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