DeltaV.. A durable, smooth flying, KFm wing

The DeltaV is a simple build "V" wing that flies well.. The KFm wing gives it a very wide speed range. It will fly slowly on very low power, and it will rocket given more power. It is very steady and smooth due to its KF wing section..The shape provides more room to fit your gear and it makes getting the COG an easy thing..

FPV can be added , there is lots of room on this shape

The DeltaV is a cross between a simpleV wing with parallel chord and a Delta shape, my first examples were made from 9mmEPP, and my latest builds are using depron and HobbyKing foams...Although any foam can be used, EPP is the most durable , and my EPP models have been bounced with no damages ...

The wings use the KFm section, the choice of either a KFm2 or KFm4 depends on the thickness of your foam, and the size of your model..

Here are the basic lines for shape.. there are now 3 sizes, ..

The 1M size KFm4 wing uses a 1000kv 150W motor, a 1400 3s lipo with a 9x5 prop, and small metal geared servos.. This gives it a good vertical ability whilst being still being able to fly at very low power at impressively slow speeds.. Max speeds with this setup are reasonable , but not excessive, for a park fly model. More power will give more speed if thats your thing..

Construction uses a KFm4 wing, pink shows the step locations top and bottom, it being 3 layers thick , 27mm, where its pink..The green shows positions for lower splines, these are about 40-50mm deep.. Tip fins are shown in yellow and are TLAR for shape and size.. For extra durability my wing was covered with laminating film, ironed on.. No spars are used, but strips of pallet strapping are fitted along the step lines above and below the wing, these are crossed over at the centre and go foreward to the leading edge.. the result is a stiff wing that is very durable..

Here a top view .. strips of velcro above and below will hold all the gear.. pallet strapping along the steps , mirrored below, makes for a very strong and stiff wing, lamination film covering adds more toughness, and stiffens up the elevons.. The REC was fitted just in front of the motor mount on top of the wing.. the lipo is also positioned on top, about midway down the velcro strips.

here the lower view.. again note the strapping..and the splines..The ESC is fitted below as seen

Below is a smaller version, made at a 26" span, this is a KFm2 wing.. the step layer being on top shown in pink.. note the green splines again go to the bottom.. This size uses the 2205-2300 quad motor , a 3s 600 lipo ,  a 6x4 kingkong prop.. and 2x 9gm servos

Top view..  construction has used both 9mm EPP and 6mm depron, it uses a KFm2 wing (top step layer).. again pallet strapping was used  for spars and covering and stiffening used lamiating film.. This makes the model very strong and tough, The model has bounced off a full speed impact with no damages

lower view

The smaller KFm2 wing is a lot lighter, so is bounced about in strong winds.. In the video it is using a 6x3 prop, but a 6x4 gave a better performance..

Basic construction.... for any size of wing

Cut a kit of parts... Laminate the main wing layer and the KF step layer/s.. profile the leading edge, add pallet strapping along the step at the rear of the KF layers, tips to leading edge, crossed over at the centre, mirror the strapping on the other side of the wing.... laminate and add splines(green), motor block(yellow) and centre wing doublers(pink).. On EPP I use lamination film to cover, on HK foam I use tape, and as a minimum, I fully cover the elevons and fins .. elevons are chamfered and refitted with tape or laminating film hinges... The motor is fitted to a ply plate, hot glued to the motor mount block.. keep the thrust lines to zero angles.

Another smaller wing has been built.. this one is a KFm4 made using 3mm HK foam sheets..
 The aim here was to go smaller and lighter with this one, I  made it at a 22" span, using an 1811-2900 with an old zagi 5x5 prop or a 6x3 on a 2s -500lipo.
I have been flying an identical power setup on a scooter pusher, getting 15min + flights.
The new deltaV wing has a fraction more area than the scooter..

The construction is as always, quick and super easy, all layers are directly laminated, making a 9mm thick wing, pallet strapping is added along the KF step lines, leading edges are then profiled, and the HK foam wing gets coloured tape as seen, elevons are also tape hinged, both the fins and elevons are fully tape covered to make them stiff and flat, and fitted , Lastly the EPP splines and motor mount block are added..
Building slowly it took about half a day whist watching the TV

 Now fully finished it weighs in at 5.2oz with its 500 2s lipo... which is 4.23ozsqft
Half power through the 1811 gives enough thrust to hover.. full power will make it go vertical.. max draw with the old zagi 5x5 prop is 6A.. which is ok for this motor setup.
I am expecting a speedy performance now I am using a higher 5x5 pitch prop.. More usually I would be using a 6x3 which gives average speeds of 20-30mph

Above is the COG calculation

Above and below show the gear positions used to achieve an accurate COG.   

Note how the Lipo sits out onto the nose extension, with no extension getting the COG would be a problem 

The aim for any of my designs is always to keep the build easy, the cost low, and use a minimum number of parts.. I use a lot of KF wings simply because they are all great fliers with a hastle free construction.. for general power models the KF wing is a winner..

The nose extension gives the wing a different look and makes it much easier to get the COG to the correct spot.. With standard "V" wing shapes I was always having problems getting the ballance, the lipo needing to be further forward than actually possible...

more info can be found on rcgroups.com