leading edge SS7

[Flybyjim]

I hung my wings (not yet covered) up from some hooks in the ceiling a few weeks ago to start working on the fuselage and today I noticed as I looked down the two wings hanging side by side that my plastic leading edges are not at the identical angle. It's not much difference but I did notice it, I guess I did not have the template pushed hard enough on the one wing to set the leading edge. Question is, is this going to make a difference in performance? I can live with it as is, not sure others will even notice it. If I were wanting or do need to remove it and set a new one I may be concerned about getting it off without damaging the spar. Any advice here would be great.

[jiott]

This is just my opinion, but if the difference is readily noticeable just looking at it, I would be concerned. The leading edge angle is an important part of the airfoil shape. The edge that points further down will give that wing more lift and also more drag, causing the airplane to fly with that wing high and farther back. Depending on how bad it is, it may be correctable by unbalancing the washout and adding rudder trim, but if any of this is done in any great amount it will be flying inefficiently with more drag than normal.

I assume you are talking about the extruded leading edge and not the fiberglass Laker leading edge. If it was me I would remove it and do over. A heat gun should soften the Hysol enough to get it off (but probably not reusable). I agree much care will be needed to avoid nicking the spar. The heat will also soften the Hysol holding the front of the ribs and false ribs, but if they are not pushed they should not move. I would also call the factory for advice.

[Guy Buchanan]

As Jim said, the answer is yes, it will make a difference. How much depends on the extent of the difference, and where it is. (Tip vs. root) One tip for a cure that doesn't involve a wing rebuild: If the difference is small enough you could build a template that encompasses both leading edges and sweep filler into the gaps while running the template down the leading edges. This would make both wings the same, but with an indeterminate airfoil. That shouldn't be a problem because our Kitfoxes have indeterminate airfoils anyway. (Except for Lowell's and others with aluminum skins.) After you sweep in the filler you could re-cover the leading edge with another layer of cloth. More weight, I know, but it might save you some work.

[ken nougaret]

Too much heat WILL distort the leading edge piece.

[Flybyjim]

Thanks for all the insight on this issue, I will take the suggestions and contemplate about this for a while. I am working on the fuselage at this time so there is no rush to correct this. I am just a bit disappointed in myself for not seeing this and still trying to figure out how this happened.

[TahoeTim]

I am wondering if you could drag a strong fishing line through the hysol to cut it loose? Probably not but it was a thought...

[Flybyjim]

That is a very good thought and idea. I work on musical instruments for my day job and have been thinking about using a hot knife, we use these to take violin tops/backs apart. Hide glue is not even close to the strength of hysol. However, I have used a very small pin point flame that heats a very thin but strong blade that gets very hot that may do the job, still pondering the situation over.