The Wait is Over

[DesertFox4]

Sounds great Dan. Happy Easter to you and yours.

[DesertFox4]

Monday was all about trimming the Laker Leading Edge. My first time through this procedure so it was nice to have the inventor of this thing looking over my shoulder. Enjoyable process. Thanks Phil.
Next weekend, more LLE fitting, trimming,bonding.


Long straight edge shows where trailing edge of LLE will be trimmed to.
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This is the distance from the wings trailing edge measured at each rib. This is where the previous photo shows the long straight edge placed for future trimming of the trailing edge of the LLE.
Your measurement may be slightly different.
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Laying down the trailing edge trim line.
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You might notice that I already cut relief for the fuel cap location to get the LLE to lay down flat.
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Wing tip end of the LLE cut flush with the rib.
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[Flybyjim]

The leading edge looks very nice, the guy who designed this option is the one in your photos? Since the wing was designed to be a flex wing how does this leading edge effect the flex wings performance. This may have been discussed before but I have not seen it and you have the opportunity to have the developer's input and I'm sure others will jump in on this also.
This is a great form for all of us builders and I for one appreciate everyones input.

[DesertFox4]

Jim- Yes that is Mr. Laker.

The composite is of a thickness that it would not interfere with the designed flex of the wing either at regular length or the "Speedster" length.

I've flown 3 Kitfoxs with this option installed, both regular wing and the Speedster length, and saw no wrinkles of any kind in the fabric or composite leading edge. The 3 have been in service for up to 5 years now. In that time and number of flight hours if there was to be a problem develop it would have shown by now. Also the LLE appears to be unaffected by our somewhat warm Arizona summer temperatures.

Aluminum has been tried with moderate success. However when the wing flexes from normal flight it does show oil-canning along the length of the leading edge. Dan Denney's bush plane has the aluminum leading edge and has oil-canning after flight. While it has no ill affects on flight characteristics or flexing of the wing, it is aesthetically less pleasing than the LLE. Our Kitfoxs are just too pretty to have wrinkles anywhere.

On an aerodynamic note- Harry Ribblet who designed the Model 4 wing, was never completely satisfied with the finished product that was sold with the Denney Aerocraft kits and consequently all others since. The model 4 wing is in principle the same wing used on all Kitfoxs since, including the model 4,5,6, and 7's. Obviously some design changes were made to increase gross weights in later models. Harry said that there was only about a foot of his actual design in that wing as sold. He intended there to be a D-section to get the full effect of his design. Now we all know how well the model 4-7 wing actually flies so obviously there was no problem with the wings sold, built and flown. It just wasn't precisely what Harry had in mind for the design.

So why am I installing the LLE on my last ever Kitfox. Again I've flown a couple LLE equipped Kitfoxs and maybe 30 give or take of the regular winged Kitfoxs and while I can't exactly quantify with hard numbers the perceived gentler stall characteristics, or the possible improvement in cruise speed, or the quicker take offs, I just really liked the way they all felt. It feels better to me and was so stated almost in the same words by the builders and owners of said equipped Kitfoxs. I think that in the coming years with so many new builders opting for the LLE that we will find out that what I and the others perceive will come to be more quantifiable. I really don't care as I like the way the aircraft feels with the LLE. Could I live without it? I am. I love the performance of my current wing. I think it could be better with the LLE. I'll let you all know sometime in the future just how much when I get some flight hours on my new SS7.

Jim, I hope my long winded response shines some light on my decision to opt for the LLE. For me, the LLE and the Quick Build wing options were must haves along with the four stroke Rotax of course.

[Flybyjim]

Thank you for the very interesting and complete response to my question. With the laker leading edge is there a difference in stall speeds and are there any reports of lower stall speeds with VG's on the laker leading install?

Thank you so much for the response, I hope to be starting my wings right after Airventure, I also bought the quick build wings.

[DesertFox4]

Jim, I wish I could flatly state a lower stall speed. Since I didn't take all 3 aircraft down into that arena I won't say yes. It appeared on the one I did attempt stalls in that the wing hung in there longer and when it did break that it felt more stable in the stall. It happened to be a Rotec radial equipped Kitfox 4 so there were more variables than if it were a familiar Rotax 912S.

Can't speak to V.G.'s yet. Haven't flown one configured that way.

[DesertFox4]

Lots of LLE scalloping today. Bonded on the last of the fuel tanks false ribs.
A full day.
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Phil made me a great sanding block out of a mixing cup. The perfect size for finishing leading edge scallops.
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Just about ready to bond on the LLE permanently. Tomorrow we bond.
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[Paul Z]

That is going to look sweet! Looks like your doing a great job.

[DesertFox4]

Thanks Paul. It's been an enjoyable process.

[SkyPirate]

deserves a truck load of these