Foam caps on the Vertical Stab and Rudder

[inzersv]

I am ready to form my foam end caps on the Vert. Stab. and Rudder. I have gone back and checked other's shaping and am wondering if there is a preferred method. I see some are rounded corners, some are squared and even one that was rounded on the Vert. Stab. and pointed on the trailing edge of the rudder. I know that it is builder's choice, but was wondering if there was any performance differences with any particular choice. I am installing the Speedster Tail Kit. Thanks for your replies.

[DesertFox6]

Hi, Stan: I didn't know which end you intend to put the little wheel on, but after checking your personal profile, I see that you are building a Super Sport so it shouldn't make make much difference. The rudder on your model is tall enough to provide oodles of yaw authority regardless of where you glue the third wheel on or how you finish the top, or the slab tips for that matter. Just shape 'em so they look nice to you. With the Speedster kit you can't really do anything else to improve the aerodynamics since Kitfox LLC has already made them as close to perfect as you can get!

I used a light coating of "Bondo"-style putty (I can't remember the actual product's name now) over the rough-cut foam plugs to provide a smooth, easily-sanded contour and surface for the fabric and to prevent the fabric from crushing the foam when shrunk. No problems after almost 13 years of flying in the desert sun!

"E.T."
(Puyallup, WA native)

[inzersv]

Thanks E.T.
As I thought more about it, and after looking through the photo gallery at the Kitfox homepage, I realized that it is just a builder's preference. There were all types of shapes in the photos. I was just wondering if there are any performance issues with one style or another? My SS7 will have conventional gear. Didn't order the Tri-gear.

[Wiley]

For what it's worth, we went out and got some balsa wood to use instead of the foam. I think it's quite a bit easier to work with. Something we didn't do, but wish we had, is to work the horizontal stab and elevator tips together to blend the contours from one to the next a little better. They look good, but they don't flow as well as they could.

[jiott]

I used the foam tips for the top of the vertical stab and rudder, but was a little leery about their vulnerability to damage. So on the tips of the horizontal stab and elevator I used balsa wood-much stronger for these areas that are especially vulnerable to hanger rash.

Jim

[inzersv]

Good point Jiott.

[MotReklaw]

Good idea....
I plan to rough shape them, affix to the rudder and vertical stab then shape them while on the plane....

.... Something we didn't do, but wish we had, is to work the horizontal stab and elevator tips together to blend the contours from one to the next a little better. They look good, but they don't flow as well as they could....