How much does the Horner wing tips add to standard tips on model 7?
George
How much does the Horner wing tips add to standard tips on model 7?
George
Kitfox 7 flying
What specifically are you asking about ?. Ie cost, performance, handling ....
David
SS7 Builder
Thanks for posting that link Lowell... and it's also corrected my spelling !. I chose these wingtips because I knew they reduced drag due to W/T vortice reduction and I think I read somewhere else that they also give you an effective increase in Aspect Ratio (beyond the physical wing tip-to-tip span measurement). But Jim, I'm interested in your comment somewhere else on the forum that you tend to get a bit of float on landing with these tips. I'm about 4 weeks off finishing my build and I'm interested to understand why that would be happening before I start on my phase 1 testing. Is your approach speed a bit high or is it just a natural aerodynamic characteristic of this type of tip ?. i.e. greater ground effect due longer effective wing span ....
David
SS7 Builder
Asking how the use of Horner tips effect wing length.
Kitfox 7 flying
David, yes I am fairly sure I get more float on landing, but this is my opinion only; nothing scientific. It makes perfect sense to me, after all the Hoerner tips add roughly 3 square feet to the total wing area-that's a lot. The greater efficiency probably cancels out the increased drag from the area increase, but still maintains the increased lift. These tips probably really help in high DA operations, but are just not necessary for the kind of flying I do. Possibly a good compromise would be to install the Hoerner tips but cut back the inboard edges quite a bit to reduce the added wing area; just keep the fancy contouring near the outboard tips. This still leaves you with a lot of fiberglass work to install nav/strobe lights. Just my 2 cents worth.
Jim Ott
Portland, OR
Kitfox SS7 flying
Rotax 912ULS
Thanks Jim. I've thought of that very idea of cutting the tips back at the inboard edge but decided against it ... at this stage. As for the F/G work for the nav/strobe lights etc.... I think I've spent more hours fiddling with this and the landing/wig wag lights than I did with fitting up and aligning the cowls.
David
SS7 Builder
I believe they add about 6-8" to each wing. If you need more accurate info, someone else may have exact measurements.
I have them on my SS7, but if I were doing it again I would go with the standard tips. They definitely add more wing area, which I think is unnecessary. My kitfox seems to float longer and has a somewhat flatter landing approach than friends I fly with who have standard tips on their SS7's. They are supposed be more efficient in handling the wingtip vortices, but I don't notice any measurable difference. Others may have different opinions. They also make it more difficult to install wingtip nav and landing lights.
Jim Ott
Portland, OR
Kitfox SS7 flying
Rotax 912ULS
George,
The length may vary from build to build depending on how a person cuts & fits the tip; however, ours add about 14" to each wing.
Dave S
Kitfox 7 Trigear (Flying since 2009)
912ULS Warp Drive
St Paul, MN
Dave's comment about the cuts is spot on. When I built my first Model IV, the plan was to fold the wings and keep it in my garage. With that plan, building to minimal folded length was critical. I cut them really short and modified the lower surface contour by grinding the glass a but thinner for easier bending to shape and then adding glass to return to the original thickness. A move rendered the need for short moot, but always liked the look vs. the droop tips otherwise available.
Tanks for info! Think I’ll go with standard tips especially since I will have wing folded issues with space as Lowell talked about.
Kitfox 7 flying