Flaperon repair jig, jury strut fairing

[wypaul 448]

I built a simple jig to bend the 1/4" radius for the aluminum for a Flaperon repair on a friends Kitfox 4. I made it for dual purpose so I can use it to bend aluminum for the jury strut fairing and the HS strut fairing.  I am using the piece of 1/4" angle for the knife edge but 2 X 1/4" strap would work as well.  C-clamps are used on the ends of the angle to make the bend.  It's a poor boy knife edge brake. The second photo shows a piece of aluminum bent for the jury strut fairing.  The whole thing was made from scraps around the hangar in about an hour.  I will post some pictures of the finished products if anyone is interested.

Also does anyone have a drawing of the KF Flaperon ribs that they will post, if not I will draw one up and post that also.

 

[Kent 27]

Thats great! I have always liked building tools and seeing other peoples approach to building tools. Here is my poor mans brake made from the scrap pile. 

[wypaul 448]

Very nice, built to last and works great I bet! I just have a little Harbor Fright model for making sharp bends.

 

[wypaul 448]

Well I flew with the new jury strut and HS strut fairings and was pleased with the results.  I was hoping for 3 mph and picked up 5-6.  I will need to re pitch the prop now.

 

[Kent 27]

Gotta love that! How did you attach them to the struts?

[Willja67 144]

What was the weight gain? Did you get any more climb performance? 

[wypaul 448]

Gotta love that! How did you attach them to the struts?

I just taped (Gorilla tape) and riveted the trailing edge and then shot in some spray foam.  Even without the foam they did not move in flight.

[wypaul 448]

What was the weight gain? Did you get any more climb performance? 

The weight gain was right at 1.5 lbs.  I used .016 aluminum. The climb performance certainly improved but it is hard to judge the amount.  Also with less drag The takeoff surely improved slightly and the landing roll will increase slightly.  I still need to fair the gear legs again and I gained right at 5 mph. when I did that last time.  The 10 miles per hour will help a lot when I fly with my buddy in his Kitfox IV but he will still be faster although I can out climb him.  That will be 115 mph when I pull back to 5500 rpm for cruise.

[Willja67 144]

What was the weight gain? Did you get any more climb performance? 

The weight gain was right at 1.5 lbs.  I used .016 aluminum. The climb performance certainly improved but it is hard to judge the amount.  Also with less drag The takeoff surely improved slightly and the landing roll will increase slightly.  I still need to fair the gear legs again and I gained right at 5 mph. when I did that last time.  The 10 miles per hour will help a lot when I fly with my buddy in his Kitfox IV but he will still be faster although I can out climb him.  That will be 115 mph when I pull back to 5500 rpm for cruise.

Thanks for posting this. Definitely going to be doing this on my bird

[flywise 169]

Not wanting to be a douchebag and criticizing good ideas for drag reduction but I would have a major worry about not being able to assess the condition of the struts, once these fairings are riveted and stuck on with tape and foam.

We are dealing with relatively thin walled tubing and it is not uncommon to find corrosion (maybe even more if you fill with foam). These struts are primary structures with very little redundancy...

 

Be safe my fellow flyers..

Edited 20 Jan 2019 by flywise
error

[wypaul 448]

Ok, thanks for your comment. The issue that you bring up is valid and with that said we have the main struts totally covered with wood and fabric, the fuselage and wings are also covered.  I guess that if I lived near salt air and/or flying off floats I would be more concerned but where I live and fly the climate is very dry.  Also I have no problem drilling out rivets for inspection.  Once again I sincerely  thank you for your concern and comments.

[wypaul 448]

Well we have the Flaperon repair almost complete.  Here are a trio of photos.  We had to build four ribs and replace about a foot of .016 aluminum.  Interesting little project.