Removing wing weight

[Rktman]

Suggestions on a fix for a heavy wing? I discovered after I epoxied both wings on that the right side wing was quite a bit heavier than the left.
With the common sense that hindsight can grant I now realize that I should have weighed both before gluing things together. Since both wings were cut from the same piece of balsa I didn't expect one could be so much heavier than the other.

So my concern is that I might have to sand the heavier wing so much thinner to lose the weight that it would affect the strength and airfoil seriously.
Any insights would be greatly appreciated!

 

[Gary Byrum]

Suggestions on a fix for a heavy wing? I discovered after I epoxied both wings on that the right side wing was quite a bit heavier than the left.
With the common sense that hindsight can grant I now realize that I should have weighed both before gluing things together. Since both wings were cut from the same piece of balsa I didn't expect one could be so much heavier than the other.

So my concern is that I might have to sand the heavier wing so much thinner to lose the weight that it would affect the strength and airfoil seriously.
Any insights would be greatly appreciated!

It interesting that I never considered that either. BUT I have worked with balsa that had the combo densities and I do know, if one piece is light and another is hard, or heavier, it's likely to be somewhat stronger. If it were a fin, I'd say you could ignore it more so than a wing. That'll likely cause unwanted pitch. If it were me, I'd opt to cut another wing of similar or matching density balsa.

 

[Rktman]

It interesting that I never considered that either. BUT I have worked with balsa that had the combo densities and I do know, if one piece is light and another is hard, or heavier, it's likely to be somewhat stronger. If it were a fin, I'd say you could ignore it more so than a wing. That'll likely cause unwanted pitch. If it were me, I'd opt to cut another wing of similar or matching density balsa.

Ugh, might have to but I'll probably have to cut both off since a replacement would have to match one or the other in weight. Complicating things is the fact that it's a twin boom, and each boom is attached to a wing. :bang: Right now there's a pronounced turn to the right that will probably turn into a death spiral.

 

[afadeev]

Suggestions on a fix for a heavy wing? I discovered after I epoxied both wings on that the right side wing was quite a bit heavier than the left.

Add some ballast clay to the lighter wing?
Drill some holes in the middle of the heavier wing, and laminate over the holes with paper?

HTH,
a

 

[Gary Byrum]

Ugh, might have to but I'll probably have to cut both off since a replacement would have to match one or the other in weight. Complicating things is the fact that it's a twin boom, and each boom is attached to a wing. :bang: Right now there's a pronounced turn to the right that will probably turn into a death spiral.

The lightning strike me for suggesting this on a winged vehicle...BUT...what about adding weight to the lighter side??? :duck:

 

[Rktman]

The lightning strike me for suggesting this on a winged vehicle...BUT...what about adding weight to the lighter side??? :duck:

Dang thing is pretty heavy already since I used basswood for both booms. Kinda overkill but I had just snapped the balsa fuselage in 2 places on another scratch built glider after just a couple of light trimming tosses, so I went with strong instead of light with this new build. Overdoing it a tad methinks.
Since it doesn't have a traditional rudder or stab I can't tweak either to compensate for the severe turn.
I gotta say I paint myself into the most interesting corners sometimes.

 

[Rktman]

Add some ballast clay to the lighter wing?
Drill some holes in the middle of the heavier wing, and laminate over the holes with paper?

HTH,
a

Now that's thinking outside the box, thanks! I hadn't considered that. It's less time consuming than sanding and won't adversely affect the airfoil. And I just happen to have a fresh supply of Esaki tissue that I can use to cover the holes.

 

[dhbarr]

And you can easily calculate how much mass to remove at which location by piling small masses on the lighter wing until you get a happy result.

 

[JumpJet]

Test glide the model. Many modelers add tip weight to get the model to turn. If your one wing isn't to much heavier then the other you should be just fine.

John Boren

 

[paulm]

I paint just one wing to make it heavier. This allows a circular glide so that I don't have to chase it for 3 miles!

 

[afadeev]

I paint just one wing to make it heavier. This allows a circular glide so that I don't have to chase it for 3 miles!

Gliders are a PITA to trim for all flying conditions.
It may fly in nice circles at 200 feet, but wind gusts at 300 feet might send it into a death spiral, or a nose dive.
It's not as trivial as having one wing heavier than the other. The variations in weight (aft vs. forward, side-to-side, etc), and adjustments to weight and ailerons trim are usually relatively small, and all have substantial impacts on glide trajectory.

And, after you've figured everything else out, a gust of wind will come along and your glider may still dive bomb into the ground, or fly away into another county...

a

 

[Rktman]

Test glide the model. Many modelers add tip weight to get the model to turn. If your one wing isn't to much heavier then the other you should be just fine.

John Boren

It's waaay heavier--bizarre considering I cut both wings out of the same piece of balsa right next to each other and carefully sanded both to the same airfoil shape using a template. I followed up with more trimming tosses, and it definitely goes into a tight death spiral even on light tosses.

 

[Rktman]

Gliders are a PITA to trim for all flying conditions.
It may fly in nice circles at 200 feet, but wind gusts at 300 feet might send it into a death spiral, or a nose dive.
It's not as trivial as having one wing heavier than the other. The variations in weight (aft vs. forward, side-to-side, etc), and adjustments to weight and ailerons trim are usually relatively small, and all have substantial impacts on glide trajectory.

And, after you've figured everything else out, a gust of wind will come along and your glider may still dive bomb into the ground, or fly away into another county...

a

Call me a masochist but despite all the frustrations, problems and pitfalls I can't shake my current glider addiction. Maybe it's the thrill of experimenting and finally having a debugged glider after all the tinkering (or...well, who doesn't like the oohs and aahs you get at the club launch when you design something cool that actually works?)

 

[Rktman]

Well the "wing lightening procedure" went relatively well. It took a lot of holes including as many as I could drill into the attached boom without compromising its strength. Once the snow has melted and I can get some tosses in, I'll see how well it worked.

 

[BABAR]

I was thinking a couple big through and through holes at the lateral low weight bearing edge of the wing, with papering both sides. Maybe insert a thin balsa lattice if the paper tends to pucker.

I think some of the Estes kits have had fins with a lattice structure, with thin balsa on the outer surfaces.

 

[Rktman]

I was thinking a couple big through and through holes at the lateral low weight bearing edge of the wing, with papering both sides. Maybe insert a thin balsa lattice if the paper tends to pucker.

I think some of the Estes kits have had fins with a lattice structure, with thin balsa on the outer surfaces.

I ended up coring out a lot of holes (see the photo in my previous post...it shows only some of the holes I eventually had to drill after some trimming tosses revealed the right wing was still too heavy). Didn't punch them all the way through though, just took out as much material as I dared, mostly near the thicker part of the wingtips. I tissued up both sides and shrank it up tight, and that hid the holes pretty nicely. In fact they shouldn't even show once I give the wings the usual black on the bottom/light on the top marker treatment.