Aircraft - Electric - Jets
Electric Ducted Fan Jet Talk
efflux RC/Air Sally....F-20, 70mm ALL COMPOSITE w/custom ducts
efflux RC/Air Sally....F-20, 70mm ALL COMPOSITE w/custom ducts
Thread starter's only
Page 1 of 6
3 view...the real thing
F-20 INSTRUCTION MANUAL.pdf
glass pieces cut to shape (i made templates)
looking down nose one piece on the bottom and 1 on the top
looking aft into the fuse,1 piece on each side that follows the conture of the inlets
a band around the tail pipe area
i inserted a plastic cup after i waxed it ,this will keep the tail pipe round as it cures
here is the rear most area of mountingh the fan
this could be the fwd spot .i may make another bulk head at the front of the hatch and then have rails for mounting HET ,WEmo,WM400.a WM 300 may work a lite setup os 3s
heres what C/N did to the wing ....he wants to cut off the extra area & use a balsa L.E. and a new root rib & tip rib. not sure i want to go there yet
not gonna be able to stand it up when the tail cone is attached
het f-16 for scale
hayoe 127mm fan
front veiw of foam plug in fuse for test fit.
from the back
SW fan center duct and foam plugs
side view this Skyworld fan has had the lip turned down to fit in this center duct ,which is the same one used in the sapac T-45 i make.
this end has a step to catch the sapac or cut down SW fan
heres the cut down sw ean ...pretty nice transition
Here the Velocity R/C WM400 fan ,in the other end of the duct (no step)
Heres the HET in the same end but has a losser fit
insert the berings in the alum tube (i used red lock tite so the berings wont fall out during stab assembly) i tacked the alum tube to the ply wood mount.the long end goes outbrd.
i then mocked up the sub assemblynote the arms are slighty pointed aft. i ground flat spots on the shaft at this angle to have some differential,more up than down
heres the flat spot ,so the aems aont slip on the shaft. i used about 5-8 degrees of differential.
option :i drilled a hole in the LE of the stab ,and added solder strips and some bb's.i then injected some Gorilla glue to hold it in place
yeah it adds some weight but .here you see the stab balanced in a neutral position.full scale do it . helps with flutter and make it easier on the small servos
insert the bering and ply assembly into the hole in aft fuse
engage the nothes and tangson the interlocking ply wood parts
i inserted a drill bit into the hole for the vert tail glass rod ,so that i couls line up the bulk head .the tail's glass rod will bond to the wood
heres a view from the back .note :i drilled the control arms out with a .118" drill bit,as i was not able to get them on the stab shafts(Sky world you should fix this) ready for epoxy to bond the assembly
here it is mocked up with the american A/C ply wood parts .sapac viper struct from Efflux R/C on map retracts .Sapac retracts will work too
i laid out the door .the one on the wing is way too big .then i used a razor saw to cut out the door.
i then cut through the rib at the C/L of where the stock spar went
i ended up taking all the fix gear wood out .becarful as the skin is damaged easily .it's a glass foam glass sandwhich
heres all the parts for the gear/spar mount. the "U" shaped piece is 3/16 thick,all others are 1/8" A/C ply
this is mocked up out of teh plane
top view.the fwd side is bonded to a spar in teh wing from the factory. the outbrd piece is partly boned to a rib left over from the stock fixed gear mount
then you mount it one piece at a tim into the wing.
@ location of new spar hole (i had to elongate mine due to i had already glued one reatact/spar holder in ple
wings on for fitting issues ,and one leg
C/F spar passing through fuse
aft view of spar and ducts, the spar clears the ducts
this is a stock part that is going to be reused ,we are moving it fwd some so we need to trim it where the black ink mark is
heres the nose gear mount cradle,it incroperates the stock batt shelf .it connects where you see the notches on the sides of the bulkhead
Sweet so it on the leggs .i have a bit to much caster in the nose strut but i needed it to get the wheel up in the nose
fan mounted here with a skyworld long can 1200 watt motor. there will be fan mounting rails that will allow ADJ of fan location
XPS 3200 4s batt goes in the nose...not the best place
heres a XPS 5000 4s on the stock batt tray perfect
C/G is where the black "+" are .im going to move the fan fwd up to the T.E. . imgoing to use a BI3600 motor and HET fan for the madien.it's a light weight set up
tail pipe fan center duct and also the taileron servo is shown
up the pipe ,there really needs to be a tail cone that is smaller and shaped more scale .this is how it was in burner
gear up you can see the steering servo up against the fwd bulkhead sitting at a @30 degrees
gear down you can see the steel cable fishing leader
added a bell mouth for ease of assembly . and it also allows for the glass and filler that might be behind the inlet lips. im not sure how they molded the lips????
top veiw of the "Y" ducts
i really like the kits batt tray ,the 2 screws are removable . the RX and wire are under the tray
pretty good stance if i can shorten the mains 1/4" it will be perfect . the full scale had a extenable NG and it had to be hiked for take off ,if not it tends to over rotate
heres the canopy cut out .i used a xacto razor saw to cut it out and leave the frame .then cut the clear canopy out and slid it in from the aft end . had to clear out some epoxy that was used to bond the upper and lower pieces together.
heres a shot of the Sapac brakes i bought from Gary at Efflux R/C. they work nice i just need some softer hose so it will bend easier .it is foling the retract movment.
main LG leg door,not toally flush but better than nothing.i will fill trhe outbrd hole with some depron foam blocks.
here is the inner wheel door ,just taped in place.i'll have to use a servo to move it .the gear are too weak to do it .this should clean up the drag a bit .
very small servo hope it can handel the speed
i'll rebond the servo cut out with silicon .in fact i bonded the servo to the upper wing skin with silicon also . it hold good and you can remove if needed a lot easier than epoxy .there was no mounting tabs on the servo.
top veiw ,that should be enough movment for low rate.
upper half and lower half of the stab
hope this is better .it is a good Camera ,i got it for my wife for christmas last year
you can just see the panel lines
start by making a slot 1 1/4" fwd of the stock spar hole.slot should be 3/4" long .
i drilled 2 .250" holes and then made it into a slot
tip dont set the wings according to the mold split line .... the left wing needs to be below the mold line ,right wing will be on the mold line . measure with a straight edge from bottom of inlets to the bottom of the LEX's
right side @ position
@ location for left side
this is the stock former the spar needs to be behind it or the wheels will hit the bulkhead. best to glue the spar holders to the former then install
here is the spar in place and inlet ducts installed ..you might have to trim the bulkhead to clear the ducts .also we are using the bluk head in a non stock location to the top of it needs reshaping . if you can make a new on out of 5ply a/c ply from loc
heres my "MAPs" in for a ck fit . the ply break away plates need to fit snugly to the retracts as the mount holes are narrow and the Edge of the hole for the screws will be too close to the edge.
Oh here the guys that did the work ,they got some tools for Christmas so i turned them loose on your wing job ..there C/N's boys so you know it was done right !.
fwd fuse ,top half ,sitting in the parting plane.ptm&w abrasion resistant surface coat and a couple layers of 2 oz. ,couple layers of 5.8 oz. and about 4 layers of 9 oz. cloth ,and about 250 ml of slow cure epoxy and about 8 hrs of labor.
note the bumps in the flange ....balls of clay,cut in half to create some alignment pegs , the other half of mold will be male ..these will be female.
this is for gary ..2x 4s 4000 mah batts. the hatch will still fit . of course the batt may need to go one fwd and one to the rear between the ducts .but this shows that it can hold a lot of batt.
note the panel lines ....these pics where take'n with the pva still on the paint
i died the epoxy grey so it looks really clean inside. over all im pretty happy with it .
flap deployed in the manovering position not C/F spar .it passes through 2 ply wood sub ribs that pick up the landing loads from the gear plate
bottom view Sapac strut,not area for servos, it should fit some 9 gram servos .flap hinged on bottom ,Alieron hinged on top.
gear retracted,nice and flush.
more bottom view wheel clears spar.
wingless F-20 ....inever never performed this operation on a perfectly flying jet before
new wings on for s trial fit ......there a bit chubby ,more like what Northrop would have built for the production plane ...if it ever had the chance.
looks pretty good eh?
those wing look a "little" better i think ...not big flaps
this wing is a bit thicker @8-9 % thickness, needs some missle rail C/N ...help me
the flaps are hinged on the bottom ,and pick up @2 square inches when lowered.the alirons are hinged on top so there is more area when the ali is deflected up ....built in alieron differential
top view of right wing mold ...just about there .now the tricky part the parting plane
here the canopy/hatch plug in the parting plane all waxed and pva'd.the grey thing are dlay shape and used for locating the mold
hatch will allow easier batt ,and systems maintenence
i'll cut out the window areas and im working on a plug for the canopy .
so all the green parts still need molds made ....dang still a ways off . maybe 40 hrs of work .
the right wing has all the panel lines on it just need to get a good fit to the fuse
side view,lot of sanding and filing to do on the aft fuse,and there are some shapeing to do on the vert tail ,there are some parts of it that are not close enough yet ...it's a sickness i know
Here you see the parting board ,note the alignment bumps..made from clay. the suface coat is being applied with a acid brush.trying not to trap any air bubbles.the grey part has been waxed and PVA applied.
the suface coat has been applied
then a slurry of cabosil and west systems #404 filler mixed with pro set epoxy to fill in the corners,and the alignment lugs
i started with 2 layers of 2oz. cloth .this helps the heavier weave not to show thru after the cure of the surface coat
i finished with several layers of 5.8 oz. fiberglass and several layers of 8.8 oz. glass.i build it up to @.150"
finished mold lookinh at it from the back side .this mold will create the inner inlet wall and inlet lip .the inlet ducts will mate up to the wall this mold makes.
fuset up in the parting board ,waxed 4-5 coats ,one brush coat of pva,note cut flange where fuse joins the nose
also a cut flange on the tail pipe ..extra work fo teh layup and prep ...but it mean faster triming when filling orders
ready for suface coat,note: the inlet lip caps positioned in the parting board
surface coat is a green blue color ...i think the sun messed up this pic.i did 2 seperate coats cure to tack free between coats
then the fiberglass ...lets see a layer of 2 oz,followed by 1 layer of 3.6 oz. ,2 layers of 5.8 oz. and about 4-5 layers of 8.8 the last being a 9oz. twill weave ..yuck ,i hate that stuff but it does lay down nice .
i think i used @240 grams of epoxy $$$
My ugly mug with the mold
overall view of fwd fuse and aft fuse (it's 2 pieces)stabs pluged in and the wing master awaiting finishing touches and mold to be made
some detail of panel lines/vents
really happy with the lots better looking tail cone
heres the layup in the mold,the white material is aerocore
heres the lower wing skin as it came out of the mold,painted,live hinge on the flap
heres the servo bay cover
bottom of wing with alieron up flap down ,retract mounted,and also the servo bay cover .i hav'nt washed the pva off yet so you may notice the paint looks funny
alieron hinged on top ,flap hinged on bottom
you can see the pva peeling in this shot
i dyed the epoxy almost the same color as the paint you can hardly see the seams.i got templates of all the parts ,so i need lazer cutting .and a jig for assembly
lower wing ,servo cover,and servo set ups
servos attached to servo cover with silicon and the 1/8" plywood servo mounts.this same set up servived the crash of the prototype.
here she is mocked up with all of the main parts molded. i made a few changes to the sturture in the wing ,snd used 2 layers of 2 oz. glass for the skins bare wing was 4.0 oz.
front view ,still learning the best way to lay it up and getting ready for production parts after we fly this baby.
here the view from the rear ,these are the old control horns from prototype number # 1 still cant find anything like them in metal.other things to note are the C/F to stiffen up the vert and horz tails,also the scale anhedrial in in the stabs too.
view from bottom looking aft ,still working on a better servo mount design...the old way did not allow removal of the servo ,so need to think on this one.
SAPAC L-39 elevator servo.
i used the stock servo mounts and modded it to have a slight angle away from the fuse inner wall ,to allow better access to the servo mount screws,servo arm screw and the bolt on the E-Z link for stab adj.
pretty straight run back to the stab control horn.i may add one more guide in the middel to help control unwanted flex.it is set up for pull for up elev.
heres the mach all alloy fan from Efflux R/C bolted to the rails w/2-56 bolts & T-nuts.note the rails are long and allow the fan to be mounted where ever you need it.the center duct can be trimmed to the length you need ,it slide on the Y duct for eas
here a pic of the stab bering tubes and the aft former
batt bay lots-o-room
full "flapage" shop is a mess ..i know full on thrash to get this finished
all hooked up
really tight gaps with hinged in the mold hinging,just a piece of 220 sandpaper to sand the gaps
all in one piece ...nice stance for a F-20
batt tray ...hey i could drill some more holes to light'n it up a tad
both "Y" ducts and the center duct which can be cut to fit for fan placement ,and it fits the all alloy .sapac,het6904,or a wemo .
started to cut out canopy frame. hope to pull a canopy this weekend.
dang camera ....looked better through the view finder..cant seem to turn off the flash ,oh well
just need to touch up the paint on the seams and a few scrathes from all the handeling
canopy came out sweet and i'll make molds from these bountry layer bleed plates when i have flown it ,need to paint them though
here 8s worth of 3200 mah batts .....2x4s 3200
heres 5s worth of 5000 mah
heres 8s worth of 4000 ...2x4s4000 so yeah i think 6s is very doable ....just the question of will it c/g ,but with the ability to maove the fan further aft i believe it can be done.
Page 1 of 6
All RCGroups content copyright © 1996 - 2015 by RCGroups.com.
Terms of Service
Mark Forums Read
Back to Top