35% Sukhoi Wing Problem
 

After 2 1/2 years of hard flying I have developed a problem in the right wing of my 35% Sukhoi. The right wing is breaking away from the internal wing tube which allows the wing to flex up and down about an inch at the end of the wing tube. The balsa sheeting is cracked at the is point as well but I have not cut into the wing to see the extent of the internal damage. I was lucky to find the problem in my pre-flite routine as I am pretty sure I would have lost a wing and ended up playing yard darts with the rest of the plane.

Has anyone experenced this problem and if so do you have any suggestions for cutting into the wing and repair of the foam core wing. Another option would be a new or used right wing pannel if one is available. I am sure Tom has suggestions for repair or replacement and I will call him on Monday.

RE: 35% Sukhoi Wing Problem
 

I don't know of anyone that has consistently flown one as long as you have;)

RE: 35% Sukhoi Wing Problem
 

I think I still have some wings in stock. We have not seen that happen on any other Sukhois to date, but this is something that always plagues sheeted foam wings. This is why I have moved away from sheeted wings on all our planes.

TF

RE: 35% Sukhoi Wing Problem
 

Thanks for the reply Tom, I will give you a call Monday or Tuesday. Yep it has been flown for a while. Probably way over 300 flights including IMAC and some serious 3D freestyle (not me I tend to be less serious in my 3D flying). I have had two or three other Wild Hare planes and have a 35% Comp Arf Extra which is a really good flyer, but I think we all have that plane that just feels right and the Sukhoi is my "feels right" plane.

I will probably open the wing up tonight and see what it looks like in there. She is still a keeper so I want to fix her right.

RE: 35% Sukhoi Wing Problem
 

I would think some gorilla glue would tighten it back down again.

RE: 35% Sukhoi Wing Problem
 

Well I took off a big piece of the sheeting on the bottom of the wing and exposed the problem. The wing tube ends in a box that is encompased by a false rib which also includes the outer servo bay. That whole assembly glues to the wing core foam and to the wing skins. The false rib, servo bay and box were all broken loose from the wing sheeting and foam core. With that whole mass sort of free loating it cracked the bottom sheeting and allowed the wing tube to wallow out the foam core towards the wing root.

I took off enough sheeting to remove the rib and servo bay from the wing and expose the end of the wing tube. Next I dug out the bottom half of foam surrounding the tube for about 6 to 8 inches back towards the wing root. The foam core is wallowed out in this area from about 1/8 inch tapering down towards the wing root. My first repair step will be to try and Gorilla glue the tube back to the wing foam, filling the gaps and securing the end box to the top wing skin. If that works I hope to be able to reglue the servo box and wing rib and finish the repair by adding new foam and bottom wing skin.

In the mean time, anyone got a right wing they arn't using?

RE: 35% Sukhoi Wing Problem
 

Just be aware of the way sheeted foam wings work.

The foam doesn't actually do anything except give the wing shape and hold things in place. The strength comes from the sheeting being in tension (pulled along the grain) and the foam just gives it a shape.

Sp pay attention to the integrity of the sheeting especially around the end of the wing tube which is where most of the force is concentrated.

TF

RE: 35% Sukhoi Wing Problem
 

Thanks Tom, I will pay close attention to that. I thought I would try and fix it first but still may need to get that new wing we spoke about.

RE: 35% Sukhoi Wing Problem
 

Got my new (used but good as new) wing this week. Thanks Barry! The servos are in and adjusted and the Old Girl is ready for another couple of years. Still my favorite all around large scale plane.

Just wanted to say how much I appreciate this forum and the help that Tom and we modelers provide to each other. Sure makes the hobby more fun for me.