"WOT NEXT" a 34" span depron Aileron trainer/sport model
after trawling through nearly all the designs in the scratchbuilt foamies section i couldnt really find what i was looking for...
"what next?" after a sea BB or any other rudder/elevator/throttle trainer for the guys i am teaching to fly at the minute? so i threw this design together in an afternoon
its a 34" span 6mm depron 4 function model, very quick to build out of just one sheet of 6mm depron, and using the cheapest 1800kv brushless and 30a esc on a 1000ma 25 3cell lipo.. it flies way better than it should and has a very soft stall, it wont tip stall either, its a peach to fly.
the video is its 3rd flight over on a regular uk football pitch and needs no more room. its small enought to throw in my MX-5 sports car yet big enough to fly in a breeze without fuss. its a two piece model the wing is held on with 2 bands. and it pootles round on a wiff of throttle, the launch in the video was at half power
what do you think? is it worth me putting a set of drawings and a build log up?
five interested persons, looks like i will have to post some plans and build tips.
i will detail most of the build for people new to depron... sorry if you already know better!
1 x sheet 6mm Depron (1000x700mm)
1 x 4ft length of 6mm dia dowel
1 x 1metre length 3x0.5mm carbon fibre strip
1 x piece 1/16 ply about 6" square
1 x piece 2"x 1/4 square wood for batterry hatch screw
adhesives.. tube of UHU POR contact adhesive, and some foam safe cyno
3 x 9g servos
1 x 2208 1800kv brushless motor (should fly on quite a range of motors
1 x 30a esc
3 cell lipo 1000-1200ma
1 x wing panel 34" x 8.1/8"
2 x fuselage sides 26" x 3"
1 x servo tray and fus formers 26" x 2"
1 x fuselage bottom 26" x 2.9/16"
1 x fuselage top 20" x 2.9/16"
1 x tailplane (incl elevator) 14" x 5.1/2"
1 x tail fin 6" x 4.3/4"
1 x rudder 7.3/8" x 3"
1 x 3" x 2" x 1/16"thk ply motor bulkhead
no need for fancy cad designs on this one, and as you can see from the cutting list its a very simple design to cut out. its basically cut 8 rectangles then trim each rectangle to make the part.
seriously... its that easy.. you dont need a computer or laser or anything else fancy! its "old skool" all you need is a steel rule, a knife and sanding block.. you will end up with a wot-next
if however you feel you cannot cut 8 rectangles from a piece of depron without the aid of a computer...
RCGroups user Potshot has drawn it up for you as a cad file here..
fuselage side... note! F2 is 5" from the front of the fuselage.. not 5" from F1
ok next we build the wing
Building the wing..
all photos are the underside of the wing..
mark out your 34" x 8.1/8" panel as below.. note the extra 1/8" width at the aft centre section so mark the centre line then the 3.1/2" wide centre.
trim 1/8" off the trailing edge of the ailerons, this is to allow for the rebating of the 1/4" dowel into the trailing edge.
just so you dont cut right throught the trailing edge...you may find it easier to cut the ailerons free from the wing then trim the 1/8" off the ailerons.. then butt them back into position into the wing to cut the radiuses at the tip.
mark the 1" radius on each edge of the aileron and strike a line forward to shape the tip, again another 1" radius to finish.
for the radius i marked and cut round a roll of solder that just happened to be 2" diameter. if you havent got anything then it will be worth cutting a disc of ply or similar to speed up marking out and cutting as the same radius is used throughout the build.
next cut the ailerons from the wing
cut a groove in the underside of the wing to accept the carbon spar 29" long
cut 3mm deep (not through) with a scalpel then using a piece o carbon spar re-cut the groove with the carbon to open it up.
then press the spar flush with the underside of the wing using the flat of a steel rule
once the spar is in, gently bend the gap around the spar open over the edge of the table and run a line of foam safe cyno along the spar and press flat onto the bench and zap with cyno accelerator
front spar.. a 29" length of 6mm dowel and short rear spar on te.. 3.1/2" of 6mm dowel
using a 1/4" round file runit along the edges of the leading edge to form a groove for the dowel
glue the dowels with por contact adhesive, put glue on the wing edge and the dowel then leave them to dry for 15minutes
place the wing on a flat surface before pressing the dowel spars onto the wing so as not to induce any curve to the wing
sand the hinge edge of each aileron at about 45degrees using a sanding block. leave a vertical flat edge of just over a 1/16" (2mm)
apply a narrow bead of por adhesive to the 2mm edge of the aileron and to the upper edge of the aileron cutout (the V shaped bevel edge of the ailerons is on the underside of the wing) and leave to dry for 20 minutes
place the wing on the flat surface, use a scrap of 1/16 ply as a spacer, place the ailerons flat on the table and bring together (correct way up)
leave to dry for a couple of hours before waggling them up and down
next cut the hole for your aileron servo and glue a couple of scraps of 1/16" ply on for the servo screws..
a quick sand round the edges, taper the leading edge dowels down to nothing at the tip..
the same methods are used for fitting the carbon spar in the tail and for hinging the elevator and rudder
Tailplane, Fin, and Rudder
the tailplane, same construction as the wing but without the 1/4" dowel
the 3 x 0.5mm carbon spar is the 10" you cut off the wing spar (providing you bought a 1metre/39" length) insert on underside of tail as per wing
cut the elevator off, leave it full width, do not cut the v out of the middle yet, as this will help keep everything straight.
sand the bevel edge and glue the hinge line as per the wing using por
now add the 5.1/2" x 3/8" 1/16" ply stiffener to the elevator using por
now cut the v out of the back of the elevator when its assembled
cut out the fin and rudder so they are ready for fitting
right i have got to go and make the fuselage...
back in a bit
Building the Fuselage
on with the fuselage.....
the main consideration with the fuse is getting everything straight and true without any twists etc. so use centre-lines to get everything even and use a small engineers square to get everything at right angles to the top line of the fuse. the wing and tail incidence are zero degrees so is the thrust line of the motor... so use a square to get it right.
the drawings (edit note: F2 is 5" from the front of the fuselage... not 5" from F1 )
cut out the fuselage sides and mark out the position of the formers and servo tray
cut the formers and servo tray from the length of 2" wide depron
build up F1 with its 1/16" motor mounting plate, note the air cooling hole. and the 2"long piece of 1/4" square wood along the bottom.
EDIT.. make the cooling inlet hole smaller than shown, say 1"w x 3/4" high.. just so your lipo doesnt try to escape!
mark out the centre line of the motor its 3/4" from the top edge, and its best to drill the bulkhead ready to accept the motor before assembly
mark out the position of the servos on the tray
and build up the tray and formers nice and square
and fit to one side of the fuse
install F2 either side of the servo tray
if your battery is slightly longer than the 1000ma i am using.. move the lower half of F2 back to accomodate the bigger battery
install the 1" square doublers in the position shown, this strengthens the location of the wing fixing dowel in the fuse side
then the 3/4" deep doublers that reinforce the battery tray
sand a bevel on the inside face of the rear joint of the fuelage at the tail
glue the two halves together with the fuse resting on its top edge
then join the rear lining up all the centre lines so its even. draw the profile onto the top and bottom fuselage faces
glue the tailplane on
temporarily fit the upper rear deck and drop the wing in place, this will allow you to cut the forward upper deck to the finished length and fit
mark the position of the wing fixing dowels and carefully make holes with a screw driver for the dowels
cut the cooling holes in the fuse sides of the battery box using a bit of brass tube, note the esc is fitted in the battery tray as well
fuselage lower cover is 22" long from the rear of the fuse and extends forward of F2, it can now be fitted
make the hatch for the battery box as shown
its now time to fit the servos and pushrods etc before the upper rear deck is fitted
then fit upper rear deck and fin.. rudder is hinged as per aileron using por
a final sanding to smooth things up and its ready to apply some trim
and that is about the size of it!
centre of gravity is 1/3 wing chord from Leading edge and mine is fine with its 1000ma pack.
control throws.. lets assume you have installed the servos with "maximum throws" as shown in the photos with the pushrods at the ends of the servo horns... be warned... this is for experienced pilots only and the control response is very very quick.
for novice pilots considering this as a first aileron model use the dual rates on your transmitter...
start off with 60% throws on Aileron and Elevator, and 40% throw on rudder... it will transform the model into a very stable and easy to fly plane.
for most hand launch take offs... half power is usually enough to get it airborne (depending on motor)
wouldnt be difficult to fit a simple wire undercart with some lightweight wheels..
or how about a set of floats? now theres a thing
who will be first to build a "WOT NEXT" ???
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