Hi,

i'm cosidering bashing a shoulder wing Ultra Stick ARF into a Low Wing airplane (see pics)

the ARF is a straight wing, and by flipping the fuse upside down it is possible to relocate the wing on the underside. Now if the wing is left alone, the plane would have no dihedral.

Being a low wing, i am wondering how stable (read: easy to fly) it would be. (?)

I'm not familar with that particular plane, but a few possible problems come to mind that you might consider:

1. If you flip the fuse over, will the elevator and wing incidences still be acceptable? If not you are going to have to modify the mounting somehow.
2. Is the wing fully semetrical or semi-semetrical? If not full symetrical, you are somehow going to have to match the top of the wing to the fuse instead of the bottom.
3. you will probably have to reverse the thrust angles on the engine mounting.
4. will you be able to re-mount the landing gear on "top" of the fuse and make it sturdy enough?

If all this works out, I don't think the dihedral or lack of it will matter much. Dihedral can help with stability and self righting of the plane, but this is not usually desirable on an areobatic plane. Just my 2 cents.

If it were easy to do a little dihedral would help on THIS setup
The rub is - the strength of the wing root is compromised
As for stability - really not an issue.
OnTHIS setup
The big change is that the relationship of th vertical area including the fin n rudder - is changed quite a bit

The application of rudder will cause roll in the opposite direction and simply turning with a banked wing (not always re'q'd) -WILL be a little different
Go ahead and do it - . See what you can learn
PS- some of my extremely aerobatic stuff has dihedral
CAPS/EXTRAS/ZLINS-all have dihedral and setup right, are very neutral .

I'm voting with Dick. On a couple of issues.

Go ahead and try it. The completed one in the attachments looks really kewl. I wish I'd done the same to mine back when I had it.

And the dihedral would be worthwhile. Look at the Tigers and 4stars for how much works.

OK, I'm going to vote twice............. Do it! No lie, it'll be unique and unique is good, really good.

(we do this for fun, right)

Agreed, dihedral works on Tigers, 4stars, Escapades, Caps, whatever. But he's not building one of these, he's building a Stick, I haven't seen any Sticks with dihedral. Doesn't mean some one hasn't done it, but I believe the Stick was designed without dihedral to achieve the flight characteristics you get by not having it. But I agree, if he wants to go thru the trouble of putting some in, it might handle a little better in normal flying. I still don't think it will be a drastic difference, but it would be fun to find out.

Nothing says novice more than the thought that dihedral is not an important design consideration. For very advanced aircraft with no roll coupling from rudder input, it's getting the proper amount of dihedral that does this. As Dick pointed out, putting the wing on the bottom without any dihedral to compensate for the wing position will make for a very poor flying airplane with adverse roll coupling. Right rudder will make the airplane roll left. A modest amount of dihedral would make it neutral, and more would make it roll to the right with right rudder. The first case makes for a terrible flight feel, the second case is what most strive for, and the third is closer to gentle sport types.

Sticks fly horribly, until you cut the wing and put in anhedral. If built as a low wing then it should have a bit of diehedral.

I don't currently own a stick. I have owned one in the past and have flown several types: Ultra stick, H9 stick 40, etc. I totaly disagree, they fly just fine for me, especially in wind. Call me a novice if you want but I can fly a Stick or 4star just fine, even a novice like me knows the difference in how they fly.

By the way, My Sig Somethin Extra and my Morris Balsa Nova have no dihedral and fly just fine also.

Sorry Jerry, but you don't understand the relationship of wing position with respect to the fuselage, vertical stabilizer and wing dihedral. When you flip the fuselage over and mount the wing on the bottom, then it is no longer an Ugly Stik. Perhaps you should do a few experiments and report back your findings. But instead of telling us what you don't know, perhaps you should listen to people that do know what they are talking about.

What a Stick has is dihedral effect. A high wing, even if it's a straight wing, will show dihedral effects simply from having the wing above midwing.

So Sticks have "dihedral", like it or not. Placing the wing low without compensation is creating an airplane that does not mimic a Stick. So he's going to create something that isn't a Stick at all.

I'm afraid I do understand the relationship and I believe I mentioned them in my first response to the O.P., with the exception of the vertical surfaces which someone else did mention. You and I may disagree on the effect the dihedral may have, but unless you have done exactly what he is wanting to do you have no more "knowledge" than I have, and I was clear to point out that I haven't. I stand by my opinion that the dihedral is not nescesarily needed and you stand by your's. I was also very clear that it was just my "opinion" and do not care about telling you "experts" anything. My purpose was to help the OP, so let him decide what he wants to try. But I did just give you two very good examples of low wing planes that fly just fine without dihedral.

Learn to do knife edge flight, four point rolls, clean stall turns. If you are doing all of these well with any unmodified stick, then you need to fly pattern profesionally.

But they are not a sholder wing or high wing without anhedral.

I think you really just want to argue, but I'll indulge you for the last time. The OP was not talking about a shoulder wing or a high wing build! He was talking about bashing a Stick (HIGH WING) and making it a LOW WING by turning the fusalage upside down.

IF I WANTED TO FLY PATTERN, A STICK WOULD NOT BE MY CHOICE, BUT I CAN KNIFE EDGE AND STALL TURN ONE JUST FINE!. I'M STILL WORKING ON SMOOTH FOUR POINTS!.

I HOPE, INSPITE OF ALL THIS B.S., THE OP HAS FUN WITH WHATEVER HE DECIDES TO BUILD AND KEEPS US POSTED!

Well when you are stall turning, it and knife edging it, what are you doing with the ailerons? Doesn't it aggrevate you at least a little?

If you feel like learning more about dihedral- try this -as another experiment.
buil a low wing plane with an aspect ratio of under 3-1-with no effective dihedral
the make another wing which will fit the fuselage with an aspect ratio of 7-1
keep wing areas about the same
Finally make a wing with an aspect ratio of 1-1
You will find that the need for dihedral decreases as the aspect ratio decreases -
Long ago - I built a Jensen Ugly Stick for Dave Brown- a rush job - I started the kit at 8:00
in th morning and gave him the plane in that afternoon about 3:00.
Those were beautiful kits -everything fit.
I can't recall if that kit had dihedral -Ithink it did
that was in about 1975
We had a Fun Fly the next day and I had a 15 size World Engines Expert stick -built upside down with dihedral
Dave had the Ugly Stick- We were 1&2 in all the events.
I won all the events expect the spin down -which was counted in number of turns - so Dave won the event
Grrr
The Stick design (Phil Kraft gets credit) is still an excellent model -there have been at least 100 versions of it -some good some awful.
The one shown in the photo is good one.

Actually the original poster asked about dihedral in his subject line. So the question actually is about what dihedral might do to the flight of his bashed model, that happens to be a Stick.

He's gotten a bunch of advice that all goes pretty much toward what he's wanting to do. Plus he's getting info about how important dihedral is for a low wing.

Thank you Dick.
That makes sense and is a much better explaination of what we all were discussing earlier. My Something Extra and Balsa Nova both have pretty low aspect ratios (shorter,wider, thicker wings) where as my Escapade has a higher ratio (longer, narrower, thinner wing, and does have dihedral) So I see your point that dihedral might help with a higher aspect wing. So my question to you now is: Does the wing on the Stick the OP has pictured have a high enough aspect ratio to need much dihedral? Or, as I said, will he be ok to just slap that straight wing on that upside down fusalage?

I built two GP Easy Sports several years ago, one is built as per plans the other is built like thisfuse fliped, wing fitted to now bottom of fuse, new slot cut for horizontal stab to get it where I thought it should be and a new slot in the now top of the fuse for the vertical stabhave a ST .61 on it and it flies much like the built as per plan versionGustof

On THAT one a little dihedral makes it more user friendly
How much?
I don't know - some -
I have this saw-

The point is that my stick with anhedral will fly exactly like a low wing stick with dihedral. That is if the dihedral is just enough to cancel out the reverse roll coupling. No need to correct the roll in stall turns, knife edge, etc.

But hugger, you're Something Extra and Balsa Nova are both mid wing models. Aspect ratio or not we've already determined some time back that they'll fly nicely without dihedral because of this wing location.

Getting back to the flipped fuselage Stik that he wants to build I'd say that it'll work fine if done as mentioned but it won't be perfect. Remember the old Top Flite Contender? That one had a rep for doing all the bad things mentioned in terms of adverse roll from rudder application. But it only bothered a few folks. Those that it did bother either added a pinch of dihedral or, as I recall, modified the wing tips to give them some upward angle so the wing acted like it had some tip dihedral. That would be a definite option for this case. It would maintain the simplicity of building a one panel "slab" wing yet provide the hint of dihedral like roll coupling. I'm thinking that if the tips were angled down it would have the same anhedral effect for the shoulder wing version. I'd just go with the stock wing and try it as the low wing conversion. If it turns out that the model displays some issues with rudder induced roll coupling to the point that it is annoying then hacking off the tips and angling them up would be far less trouble than cutting into the wing's center section and attemping to arrange for some dihedral. I'm assuming here that it comes with a one piece wing in the box. If it's a two piece setup that you join then adding a touch of dihedral would be quite simple. Just a new joiner with a "kink" in the middle and an angled wedge of sheet balsa as a gap filler.

Also daRock mentioned above about how just flipping the fuselage would raise the fin and rudder area and how this would increase the rolling side effect. That's an excellent point and suggests that the fuselage should stay in the original configuration. To convert to a low wing configuration just make a new cutout in the sides and bottom which would then be glued onto the upper wing mount area. That would maintain the fin and rudder area being low and fairly centered around the thrust line and go a long way to reducing the adverse rolling effect you'd get when flying knife edge.

I stand corrected, I guess technically the Balsa Nova and SSE are considered mid-wing. But you basically said the same thing I did: try the straight wing and see if it needs dihedral first. I think Dick's comment about the "saw" was alluding to the same thing you did about the wing tips. This is also what I would try first if I did have some adverse roll coupling, unless as you said, it is a two piece wing, then I would add dihedral there.
I think the OP wanted to flip the fuse to save time and effort as opposed to cutting a new wing saddle etc., but if he really wants this thing to fly easily, then I also think he would be be better off to do that instead of just flipping the fuse. Again, just an opinion from another "novice".

For the perfectionists