Pretty sure it's not a problem, but is loss of dihedral ?

[jklong03]

I've noticed that my cub's wings have lost some of their "natural" dihedral, in that when at rest the struts are loose. Of course when I pick the plane up by the wingtips, the struts take up the slack and the things appear normal. I'm assuming that in flight the lift of the wings causes them to lift as much as the struts will allow, thereby restoring the dihedral angle to normal.

I'm almost embarrassed to ask this question in the open, as my career before I retired was in aircraft flight testing, so I'm pretty sure I disagreeumption is correct. However, I did notice a thread where someone used fishing line to "restore" their dihedral at rest and that got me thinking that I wasn't the only one who has noticed this.

I just wanted to double check with someone (flydiver perhaps?) that this droop at rest is a non-issue.

[jklong03]

Followup,

Flydiver, I read your post about reinforcing with the dihedral, and from your description, I think I will go the LHS and buy the supplies to do your mod with carbon fiber and dihedral.

EDIT: No wait, I just remembered I had the wing I had put aileron mod on before out in storage room. I forgot that I had braced that wing for my second attempt at ailerons with dihedral in it, because I was so shaken by my unsuccessful attempts to fly a flat wing with ailerons. That was before I admitted defeat for the time and went back to a non-aileron mod wing when I put my Park 480 outrunner in her.

So now I took the carbon fiber rod brace I made, it is two rods with a popsicle stick "box" for the base and to establish the dihedral angle.


Gonna Gorilla glue that baby in tonight! And once done, I'll see how the struts "hang" then.

[flydiver]

That was a long time ago. I did it because I didn't want to bother with the struts. If you use struts you shouldn't need the reinforcement. It's a choice.
Even with the reinforcement cracks developed after about a year right in the root area at the bend point that needed further carbon reinforcement.

The wing flexes and softens over time. This is why there are stunts. As you've seen, some folks try to get away without them. You can for awhile...then > disaster.

[ted]

My struts are relatively loose with a new (month old) SuperCub. However, they do tighten up when I pick up the SC by the wing tips. I guess they're there to keep the wing from flexing up too much during flight.

[spindeepster]

The fishing line thread was mine.

supercubclub.proboards.com/thread/4875/recovering-dihedral

I keep it tight...I use this plane with a buddy box to introduce interested parties to the fun of flying. The kevlar fishing line does not stretch or sag and is a beneficial addition to the plane. Obviously if you're going to add ailerons then you're going to want to flatten the wings.