flattening a Sophisticated Lady wing

[Steve Boone]

Has anyone tried flattening a Sophisticated Lady wing and adding ailerons and flaps? If so, how did it turn out? I'm thinking no polyhedral but the same dyhedral or flat center section with poly.

[lincoln]

It won't be any faster, or at least not very much, and you'll probably still want to use a bit of rudder when you turn. Maybe faster in roll, though.

I once had a Gentle Lady to which I attached a wing with a faster airfoil. It was a pretty nice glider.

[flystoolow]

Not worth it, but it will work fine.

[prodjx]

Don't forget the aileron differencial 2.5-3 to 1, up to down flat bottom airfoil's need it. Dave.

[Hostage-46]

I had a full house Spirt, all those servos, and the RES version was lighter and flew just as well.

[Steve Boone]

I wasn't hoping for a huge gain in performance as much as making it easier to tow. I have a RE Spirit we tow and the lack of ailerons makes it interesting at times. I do have a flattened wing (no poly, less dyhedral, flaps, ailerons) for it. It hasn't flown yet to with it on due to the lovely Indiana weather this time of year.

[Robglover]

I saw one flattened due to pilot error once. Nobody tried to fly it afterwards.

[Steve Boone]

Now that's funny. :D

[Hostage-46]

I wasn't hoping for a huge gain in performance as much as making it easier to tow. I have a RE Spirit we tow and the lack of ailerons makes it interesting at times. I do have a flattened wing (no poly, less dyhedral, flaps, ailerons) for it. It hasn't flown yet to with it on due to the lovely Indiana weather this time of year.

As in Aerotow? I guess I can see that. The full house Spirit worked as a good trainer for more advanced concepts in radio programming etc.

You could leave in the poly and still put in ailerons, just use them for tow...

sounds like a whacky scheme, the kinds of stuff I like!

[atjurhs]

I saw one flattened due to pilot error once. Nobody tried to fly it afterwards.

Why not? Did it still have a tow hook? It should be winchable :D

[BMatthews]

If you do try this you'll also need to make the vertical tail area smaller as well. Probably aim for around 2/3 of the present area. If you don't then it'll be spirally unstable and want to wind itself into a spiral dive all the time.

[Steve Boone]

Too late for that as I already have it built. In fact I've about got the fuse done as well. I'll be starting the wing late tonight or first thing in the morning.

[JINKSd]

Steve
Several years ago I built a lady wing and added ailerons and flaps. With the original dihedral /polyhedral set up. The ailerons did not work worth a crap. The flaps worked great on launches and landings.
The straighter the wing the better aileron control.

Also

I built the spirit 100-sport wing with ailerons and flaps. Using the sport Dihedral /polyhedral. The ailerons worked but it was boxy. There’s just a pinch to much polyhedral for good aileron control. It would have been way too much work to remove some polyhedral so I made the Dihedral straight. (New straight joiner) man that really improved its performance. I’m not saying it’s a perfect wing. I’m just saying it flies a lot better.

JINKS D.

[Elmog]

Jim's Flying Service

"Planes Flattened While You Wait!"

[BMatthews]

Too late for that as I already have it built. In fact I've about got the fuse done as well. I'll be starting the wing late tonight or first thing in the morning.

It's worth the time to either modify the vertical tail to make it smaller or make a new one.

Or at least realize that if you find you need to hold a lot of "top" aileron trim in a turn then it's your fin being too large. A smaller fin will reduce the need to hold that top aileron input to prevent the model wanting to tighten into a spiral dive.

[lincoln]

Lots of aileron planes are spirally unstable. But they can still be flown. You can compromise, as some of the dlg's do, and put in a moderate amount of dihedral, say, 5 degrees on a side or something. I used to fly an Io, which had only a little dihedral, and a pretty large fin on a long fuselage. Once I was used to it, it flew quite well, and was easy to spot land.

[BMatthews]

Yes they are, I've flown a couple of them. But why learn to compensate for this trait when a solution is so easy? When the vertical area is optimised to be just right it makes the models so much more pleasant.

Here's a picture of my old hack ship after I did my flight trials starting with too large a fin and cut it down until it was too small and then redid the fin. Dihedral on this one was around 3 degrees per side. Note the rather small looking fin size. In the form seen here the model was a delight to fly with only a breath of top aileron needed for only the steepest of turns. Up to around 30 to 35 degrees I actually had to nudge a little bit of pro aileron into it to hold the turn. Between around 35 to 50 it was nuetral and more than that and it needed a nudge here and there to avoid tightening up.

[sailhigh]

Steve,
The answer is yes. I have build a Gentle Lady (same geometry as SL) with ailerons and it flies beautifully. Keep the original dihedral, delete the polyhedral and get ride of the tip washout. Mix in rudder with ailerons and it will turn just as tight as as R/E version.

[Steve Boone]

Sailhigh: What size and placement did you use for your ailerons?

[sailhigh]

I used 20% chord for ailerons. Aileron starts next bay after the polyhedral rib and ends one bay before the end rib.