doubledee

My Feedback: (4)

I've done a search and have been overloaded with superflous information, the ARF or RTF forum has nothing, the search engine is pretty worthless, so I will post my question here.

I've heard removing the dihedral from the wing of the big stick 60 causes the wing to appear to droop. If so, what effect will this have on the flight characteristics of the airplane and will it be OK to remove some or all of the dihedral in an effort to maybe improve the aerobatic capability of the aircraft? If I remove some of the dihedral, how much should I remove? Or maybe I should leave well enough alone as it flies very well as designed. Would appreciate your thoughts.

Thanks,
doubledee

hogflyer

The plane will definitely have a drooping look to the wing. That is the way my Sweet Stik’s used to look with their flat wing. As far as flying, I don’t think it’ll affect it much, but why change to a flat wing when the design flies good as it is?

Hogflyer

2HI2C

You really won't notice a big difference in the way it flys but it will do a better knife edge.

carrellh

If it's already assembled there's no way I'd cut it apart for this mod. Mine has the dihedral and I'm very happy with it.

aerowoof

wings with no dihedral do appear to droop plus the rudder will be less effective.meaning when you apply rudder about the only thing that will happen is the nose will turn a bit .also the dihedral was added to the design after it was found that alot of airleron throw would induce adverse yaw.the original stick designs did have a flat wing.

Ed_Moorman

My Feedback: (1)

Here is an part of one of my columns from R/C Report on dihedral and stability. Also some photos of my high wing planes.

Roll Stability:

Let’s talk about dihedral. In the first place, there is dihedral and there is dihedral effect. Dihedral is the upward bend in the wing. If the wing is bent downward, this is called negative dihedral or anhedral. Dihedral effect is the result of having dihedral or other things that make your plane react just like the bent wing does. Dihedral effect gives your plane roll stability. It also results in roll coupling.

Let me make my position clear from the git-go. In RC terms, I do not want any roll stability. In engineering terms, I want neutral roll stability. In English, I want the plane to go where I point it and stay in the attitude I place it in. I think this is a pretty common desire for all acro fliers.

Dihedral generates positive roll stability and it will cause roll in the direction of the rudder. Anhedral generates negative roll stability and roll opposite to the rudder.

Two other things give dihedral effect, wing sweep and wing location on the fuselage. Sweep back generates positive roll stability and roll with the rudder. Sweep forward will cause the opposite.

Wing vertical location on the fuselage causes dihedral effect. A high wing location is equivalent to about 3 degrees dihedral on each side. I surmise this because it normally takes me 3 degrees of anhedral (angling the wings downward) to cancel out the dihedral effect. A low wing location will cause the opposite. If you have a low wing plane, you’ll need a little dihedral or sweep back to cancel the effect of the low wing location.

Most of you have flown a plane that was really unstable in roll, but you didn’t know it. When it’s inverted a Big Stick is unstable in roll. A Big Stick has a high wing and a small amount of dihedral. Turn it over and what do you have? A low wing plane with anhedral. Disaster, right? No, just a pain in the neck to fly. Even worst is a high wing trainer with more dihedral. Even fly a trainer inverted. Wasn’t it a pain to keep the wings level and to make a turn? Sure it was. The plane was roll unstable. It wanted to roll back over and get stable. It wasn’t a disaster, but it was work compared to a sport plane that has a low wing and dihedral. The low wing location and the dihedral cancel each other out, giving you a neutrally stable plane. Flip the low wing sport plane over and what do you have? A high wing plane with anhedral. That’s why I put anhedral in most of my high wing planes. A high wing plane with anhedral will do knife edge, point rolls and outside maneuvers much better than one with a flat wing and a great deal better than one with dihedral.

You can see from the photos that I have a lot of experience with high wing planes with anhedral. My present Stick is the red & white Ultra Stick with an OS .55AX. Great combo. No roll in knife edge and does knife edge loops. I did mix out the pitch with down elevator when I put rudder in.

Look at the nose on photo of the yellow Joss Stick that is inverted in the cradle. It could easily be a low wing plane with a little dihedral.

FLYBOY

My Feedback: (11)

I have built many Stiks with no dihedral. Will never put it in one. It flies like a trainer, but does aerobatics like anything you could want. You will love it! One of the most fun birds. I have always had one in my fleet. Fun on floats and skis too! 10 times the plane with the dihedral out, well, maybe not, it is a good bird with dihedral too, but with out it, WOW!

OzMo

My Feedback: (3)

I would not cut the wing either. However stick plans are free for just a little looking here on the scratch build forum. Build a flat wing and have your cake and eat it to

doubledee

My Feedback: (4)

OK, I appreciate the responses and Ed Moorman's very informative post. The kit is an ARF and I have been considering removing the dihedral when I glue the wings together. What I get from your responses is that it will, in fact, fly better with the dihedral removed, and that makes me wonder why the designers added dihedral to the wing. Unless it was to tame the airplane down a bit in an effort to widen the market.

Thanks again,
doubledee

B.L.E.

If you haven't glued the wing halves together yet, go for it. You will basically turn it into an Ultra Stik.

Matt14x

While your at it, make it a 'bottom winger'. You'll love it.!