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Modifications I have made to various FT designs

#1
I have had many problems with the default FT models/plans in various ways. This thread is intended to show others what modifications I have made to fix those problems before they even show up. Each post I make will be dedicated to a model. I will edit and add any extra changes I have made to previous posts so that you only have to look at one. The posts will be in the order that I built them.Keep in mind that not all of these mods are necessary or helpful to everyone, I like my planes to fly fast and pull high Gs. I also want to preface that I'm not trying to degrade the FT team's work, I find the planes amazing already.
 
#2
First up: the Tiny Trainer, of course.
I will split this one up into the sections of the plane and any joints between them.
FUSELAGE
1. added foam plate between wires and servos to prevent tangling. Left an air hole for better flow to the ESC.
2. placed skewers along leading edge of elevator and rudder with CA glue for better rigidity.
3. Added a half closed off section to the spot where the hole is and turned it into a battery hatch, locked using velcro on the front end.
POWERED NOSE
1. lined the inside of the skewer holes with glue so they had more friction and did not deform.
2. added a small compressor piece to direct air to the ESC.
GLIDER NOSE
1. added a small hook to mount a tow cable, wrapped with tape around a skewer piece, glued into bottom of nose
TRAINER WING
1. fiber taped the center section and coated with epoxy (thin layer)
2. added skewers to underside crease of wingtips for rigidity, made sure to glue to bottom of main wing section.
SPORT WING
1. same as the trainer wing
2. covered servo holes with tape
3. added skewers to trailing edge of ailerons for rigidity

this is probably the largest post of them all because of the different modules. hope it helps!
 
#3
next on the list is the simple scout, which is relatively short
FUSELAGE
1. added skewers to leading edge of tail (this one is going to be repeated a lot)
2. permanently glued skewers for power pod because they moved too much
WING
1. added a ~8" carbon rod before gluing
2. added skewers to trailing edge of ailerons for rigidity
3. aluminum taped center because it was the only stuff i had on hand (probably would have still fiber taped it)
 
#4
third is the FT Arrow.
1. made side compartments lockable via velcro
2. crossed minor gaps between the pod and the wings with popsicle sticks before gluing shut
3. glued winglets using CA so they wouldn't delaminate
4. added tape to the front of the pod to prevent dirt and stuff from getting all over the glue
5. added skewers to trailing edge of elevons
6. added skewers to the bottom of the winglets to act as skids
 
#5
now we get into the really tough stuff. FT spear:
1. added a balsa center, birch plywood lined flitch beam that stretches from one leading edge piece, through the power pod to the other side. This allows for waaaaaay more aggressive stuff without ripping it in half from a 4 G turn like I did. you can make it shorter of you like but it gives the spear enough inertia to reach much faster speeds.
2. CA glued winglets and added skewer skids
3. added a small foamboard box for a 1300 mAh 4 cell
4. taped all corners of the main box
5. added skewers to trailing edge of elevons
6. added plywood segments to control horns for extra strength
these mods get the spear up to around 120 mph in a dive with mild wind. have fun ;)
 
#6
second to last for now, the edge 540
1? this doesn't really count but I cut out some paper with rc logos on it and glued them all with CA because it looks cool
FUSELAGE
1. added small seat for a battery to be mounted without straps
2. added rubber band pieces as friction padding for battery
3. added a plywood piece under the power pod so it wouldn't flex at all
4. replaced skewers to hold wing with carbon rods of the same diameter
5. added popsicle sticks to underside of the elevator and rudder sections that extend forward to prevent bump damage
6. Added pylons in the cowling to prevent any further scronch
WING
1. fiber taped the center, covered with a liberal amount of epoxy
2. added carbon tube spar, ~18", about 1 cm diameter
3. added skewers to trailing edge of ailerons
4. added skewers to outside surface of winglets to prevent bump damage
 
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#7
and the last one for now: the FT bushwacker (modifications may be added on)
FUSELAGE
1. added a small rectangle to inside of tail to prevent bump damage
2. added skewers to bottom of elevator bits that stick forward and to top of rudder
3. chopped off most of the power pod and added a small carbon rod to keep the same rigidity
4. added a foam box below the power pod with some velcro at the back for the battery
5. added a few guide pieces on the top of the tray so the receiver could be oriented better
WING
1. fiber taped the center and covered with light epoxy
2. added popsicle stick to both sides of the center of the spar
3. added skewers to trailing edge of flaps and ailerons
4. added skewers to sides of wing to prevent bump damage
 

Grifflyer

WWII fanatic
#8
second to last for now, the edge 540
1? this doesn't really count but I cut out some paper with rc logos on it and glued them all with CA because it looks cool
FUSELAGE
1. added small seat for a battery to be mounted without straps
2. added rubber band pieces as friction padding for battery
3. added a plywood piece under the power pod so it wouldn't flex at all
4. replaced skewers to hold wing with carbon rods of the same diameter
5. added popsicle sticks to underside of the elevator and rudder sections that extend forward to prevent bump damage
WING
1. fiber taped the center, covered with a liberal amount of epoxy
2. added carbon tube spar, ~18", about 1 cm diameter
3. added skewers to trailing edge of ailerons
4. added skewers to outside surface of winglets to prevent bump damage
I'm going to try some of those when I get to building a Edge.
 

JennyC6

Active member
#9
now we get into the really tough stuff. FT spear:
1. added a balsa center, birch plywood lined flitch beam that stretches from one leading edge piece, through the power pod to the other side. This allows for waaaaaay more aggressive stuff without ripping it in half from a 4 G turn like I did. you can make it shorter of you like but it gives the spear enough inertia to reach much faster speeds.
2. CA glued winglets and added skewer skids
3. added a small foamboard box for a 1300 mAh 4 cell
4. taped all corners of the main box
5. added skewers to trailing edge of elevons
6. added plywood segments to control horns for extra strength
these mods get the spear up to around 120 mph in a dive with mild wind. have fun ;)

Wish I'da known this before I built mine!...though I have doubts itt'l be pulling 4G when it's pushed along by a pair of Cox 0.049s(I'll be lucky if I get mine to fly much past 50MPH with a tailwind haha), still, nice to know. If I ever need to do a deep rebuild or flat replacement of the airframe I'll probably make a fair few of these tweaks. Especially t hat birch spar; I put full tricycle landing gear on mine and I had to A: mount the main gear farther back than I'd prefer and B: put a bunch of wood strips down in the floorboards to help shure things up back there so the gear didn't collapse on the first mildly hard landing.


Curious question...have you ever looked into blending the wings to the fuse? Right now it's a rather harsh transition, I can't help but wonder if the aerodynamics would improve if it was smoothed over and streamlined a bit.
 
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#10
Curious question...have you ever looked into blending the wings to the fuse? Right now it's a rather harsh transition, I can't help but wonder if the aerodynamics would improve if it was smoothed over and streamlined a bit.
Actually, if you were to expand those center fins it comes with you could get rid of all the vortices and the center would act as an aerofoil on its own. I haven't looked into smoothing but if I did smooth it I would use solid foam blocks and sand them down after I glue them on.
 

JennyC6

Active member
#11
Actually, if you were to expand those center fins it comes with you could get rid of all the vortices and the center would act as an aerofoil on its own. I haven't looked into smoothing but if I did smooth it I would use solid foam blocks and sand them down after I glue them on.
Not sure how much of that I could do on mine...two 5x3x3 props and a couple of tiny buzzy engines on the back limit how far back they could be extended...might help with engine cooling though. Hmmmmmmmmm. Might make rigging rudders a bit easier, too.

I had a thought on that topic, too. I want yaw control but I don't really trust the mixing in either my radio or my FC with not choking one of my engines to the point of flameout if I give it full deflection(And I'm not sure it'd be strong enough anyway given each engine only pushes ~45 watts at full blast), so I've considered aerodynamic solutions. Differential drag is an option of course, but I thought it might be more prudent to pull a page from the bayou's favorite runabout and put a rudder directly behind each prop, where it'd be using the propwash instead of the airstream to provide authority. Should be a whole hell of a lot stronger and may just be strong enough to give enough yaw authority for confidently pointing the nose on landing and making coordinated turns, if nothing else.

Using the center section as an airfoil would make it a bit tricky to do some FPV stuff with them, at least if done as FT intended. Mine would be fine, but if you lodged a nice fat Session 4 and Runcam HD boardcam in the nose as designed, you'd pretty much destroy the majority of that airfoil. I've got a boardcam on mine, but since I don't own a gopro, I instead put a nosegear servo in that spot and then put the panel I cut out back in again.

On the blending/smoothing, my thought was some posterboard with some foam supports in key areas so the air pressure against it doesn't just collapse it. Dunno if that'd be any lighter than solid foam carved to shape.
 
#12
Just wanted to add on that I use this industrial velcro called duallock for all my electronics and battery compartments/hatches. It doesn't come off in flight at all, and when you take it off you won't peel the paper on the foam if you start from one side and work your way across. It's a nice universal system for mounting pretty much everything.
 
#13
Just wanted to add on that I use this industrial velcro called duallock for all my electronics and battery compartments/hatches. It doesn't come off in flight at all, and when you take it off you won't peel the paper on the foam if you start from one side and work your way across. It's a nice universal system for mounting pretty much everything.
that stuffs awsome! I ran out of it a little while ago, might have to get some more! Great suggestions btw, really helpful stuff.