Sidewayskiwi
What is the ideal thickness of the KF plates (in my case KF4)
What thickness gives least drag best lift and strength 
My choices are
6mm depron homenade out of 2x3mm sheets
3mm depron sheet
4mm paper off Adams  readiboard ( think E3Scott is a fan of this )
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solentlife
I'm not a believer in KF aerofoils as better than flat plate ... but do appreciate the stiffness it can add.

Personally I usually alter plans that say 2 or more 6mm ... to a main 6mm and then the KF in 3mm, with a decent resin based laminating glue to add also stiffness. 

Its only when I need to create a total stiff structure such as the Hunter / Vulcan - that I use multiple 6mm ... but then its two sheets same making a complete 12mm wing / fuselage.
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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DualDesertEagle
What is the ideal thickness of the KF plates (in my case KF4)
What thickness gives least drag best lift and strength 
My choices are
6mm depron homenade out of 2x3mm sheets
3mm depron sheet
4mm paper off Adams  readiboard ( think E3Scott is a fan of this )


On all my models that had a KFm-2 airfoil I simply used the same stuff the wing itself was made of and then mostly just made it 40% of the wing chord.

My F-13 V3 and my BF-109 were entirely built from 3mm depron (tho the F-18 was scaled down considerably), so the KF steps were 3 mm as well.

My current MiG-29 and X-31 are made of 6mm depron and so are the KFs.

And having flown a profile aerobatic plane with no KF before the similarly shaped BF-109 I do find it feels better to have the KF-airfoil on the wing, feels more controllable to me and the stall characteristics seemed to be a lot better too.
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Sidewayskiwi
solentlife wrote:
I'm not a believer in KF aerofoils as better than flat plate ... but do appreciate the stiffness it can add.

Personally I usually alter plans that say 2 or more 6mm ... to a main 6mm and then the KF in 3mm, with a decent resin based laminating glue to add also stiffness. 

Its only when I need to create a total stiff structure such as the Hunter / Vulcan - that I use multiple 6mm ... but then its two sheets same making a complete 12mm wing / fuselage.

Iam building the replacement SU34 V5 but at 34 inch wingspan (like the last one that servo failure destroyed) 
Going KF4 as we live in a windy area and the increased stability 
So most probably go 6mm for kf's as the paperless DTF is softer and more prone to damage 
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solentlife
As I say I am not convinced about the aerodynamics of the KF .... if you look up the history and testing of it ... it had a very limited flight envelope in which it added any benefit ... most reports I've read have said that the benefit was outweighed by the construction and was why it never caught on in any full size AC. 
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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F1wanabe
I actually found the best performance on some planes to be a 6mm upper and 3mm lower kf airfoil.  This gives good speed and wind stability with just a tad more lift for slow flying. On a SU 35 it is spectacular!!!
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Sidewayskiwi
F1wanabe wrote:
I actually found the best performance on some planes to be a 6mm upper and 3mm lower kf airfoil.  This gives good speed and wind stability with just a tad more lift for slow flying. On a SU 35 it is spectacular!!!

hadnt thought of that 
SU34V5 has gone 6mm upper and lower 
but SU30 plans are dusted off might use that idea on that
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F1wanabe
Let me know what you think!
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