Attaching wing endplates

[Kiwi55]

I understand that at the end of the wings on the Double Eagle (and possibly the other eagles) are wingtip endplates. These are approximately 1" larger all around that the actual wingtip.

After some research I understand the purpose of these.

So how are they attached?

I guess they can either be permanently attached or removable. If permanent the simplest way would be to simple glue them to the end rib. If this is done how does this effect the wing covering? Does the covering just butt up to the endplate and stop or is it wrapped around the endplate?

If they are removable how have people attached them?. I'm guessing there could be quite a lot of load on the endplates in some situations such as a slip. Are they just screwed to the end rib? seems this would compromise the end rib. Is some other provision made for attaching them?

Your input is much appreciated...Paul

[Dan_]

So how are they attached?

The ribs at both the root and tip ends are double ribs with a plywood strip holding them together.  This makes it very easy to add blocks for wood screws.

[Kiwi55]

So how are they attached?

The ribs at both the root and tip ends are double ribs with a plywood strip holding them together.  This makes it very easy to add blocks for wood screws.

Yes I put the plywood strips on last night. I can see from your picture where you put the screws. I'll add the blocks. That helps alot.
Thanks...Paul

[Dan_]

Yes I put the plywood strips on last night. I can see from your picture where you put the screws. I'll add the blocks. That helps alot.
Thanks...Paul

Paul,
Steve tells me he put 3 sheet metal screws (also called self tapping screws)  through to each spar tip end, on his Legal Eagle.  Apparently nothing else to hold it.

I suppose one could add a bead of silicone adhesive caulk.  

Double Eagle is flown faster so a small wood block here and there would seem appropriate...  Perhaps small brass or stainless wood screws. (coarse thread)

[Tom H]

On DE Stubby, we did what Dan describes - glue small wood blocks on the inner side of the rib cap strips where they seemed appropriate, located the wing end plate, drilled pilot holes, screwed on with sheet metal screws, including into the end of the spars.

[Kiwi55]

Last night I added small wooden blocks as suggested.
Thanks...Paul

[joecnc2006]

An example from Leonard's site on LE.

[MrG]

Does it really help with wing tips?
or is it mainly a looking thing to clean the ends up?

[joecnc2006]

Without the winglet the high pressure on the bottom of the wing will wrap around the end of the wind in flight and interfere with the low pressure on the top of the wing causing a slight decrease if lift at the wing tip, and  in turn helps keep from loosing the low pressure at the tip of the wing from falling off at the wing tip and decreasing the surface area which would contain high lift air pressure. If you take a look at some birds feathers at the end of their wings you can see a few feathers in an upward direction, this is where the idea originated from.

[Tom XL-7]

while we are considering wing endplates I would like to remind or inform as it is that Joe Spenser spent some time on endplates as they applied to his L.E. .
Don't recall if on here or that old site. I visited the old site this morning and quickly was reminded why we are here. I did not succeed in anything I wished to do.
Well in short He ended up with an abreviated endplate. I recall he found the fence hanging down was the critical part so he eliminated the above wing part.
There were probably dimentions as far as how far the hangy down was and whether it was consitent front to back or not. Useful stuff. 
It's out there somewhere.
Tom XL-7

[scottiniowa]

In the interest of progress, I could easily use the power of CAD to draw any determined shape and post the file for the wing tip. But, I would like to do only for proven gain.
This is fairly simple statement.   i.e.   With nothing on the wing, it stalls/lands at say 34 mph   With- 32 mph and stable  Easy math shows that to be 6.25% improvement. Fairly large.

That being said,  if all the work that anyone does, cannot be measured- i.e. NO gain or loss  Then it would just be a exercise in creating a "look" and adding some weight to your plane.

Please don't read this as if I am thinking this is a "waste of time/material"  I think it very well could be a good addition to your aircraft and it would be nice to be building it, (the wing tip) that would be of gain to your flying.

I know drawing this shape could take many hours at the table figuring out just exactly what shape you want. Thus my offer, if someone comes up with a proven winner, I will draw it out to your specs. And post. The power of CAD lets me do most anything.  With the simple-list being,  wing rib shape, plus, 1" or 2" or what ever, the entire circumference of the wing rib shape.  Again if this shape is not proven to be of gain, I simply don't see the need for the work.

Just offering my service on this for the gain of all.

[joecnc2006]

I could not find the message thread on the yahoo group yet, but here are pictures of the mod as tom mentioned.