Aircraft - Electric - Airplanes
Extreme Flight 64" MXS EXP official build, fly, and video thread!
Extreme Flight 64" MXS EXP official build, fly, and video thread!
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First let's remove any wrinkles in the covering that may have developed during transit. Before you get any heat near the covering, remove the canopy...it is heat-formed and will distort if you get the heat gun or iron too close to it.
I like to start by laying everything out on a clean work bench. Servos, motor, ESC all on the left end.
Cowl, rudder, stab/elevator, hardware pack, wheel pants.
Racing wing tips, SFG's. BTW the tips for this thing are amazing...they are half laser cut, half carved and sanded from balsa. They are incredibly light and the covering is wrapped around them like paint. Amazing workmanship.
Start at least a few inches away, keep the heat gun moving, and be patient.
I also like to use the iron to seal the covering to the wood at the seams. Totally optional but it can keep the covering from loosening up down the line if you leave the plane in your car on a hot day or something.
Next let's get the wings ready to go. First get out the hinges and horns for each wing.
Locate the hole for the aileron horn and clean it out if necessary.
Sort out the horns. The elevator horn is shorter than the other three; the rudder and aileron horns are identical.
Fit a horn reinforcement plate to one aileron horn with the matte side down.
Test fit the horn into the slot and make sure that it fits nice and flush.
Mark the area on the covering outside of where the horn reinforcement plate goes.
Remove the horn temporarily and cut away the covering where the plate will bond, leaving about 1/16" of covering inside that line. The glue that holds the horn down will also overlap the covering slightly and keep it from peeling later.
Lightly scuff the gluing surface of the horn with some sandpaper to promote good adhesion.
Mix up some 30 minute epoxy. Apply a little to the horn and a little to the slot.
Insert the horn and make sure you've pressed it all the way in flush.
Wipe up any excess epoxy that escapes with some alcohol. Make sure the excess epoxy is entirely cleaned up now because once it's cured it will be difficult to get off.
Here's a tip for the hinges that's totally optional. First, make a mark on the centerline of the hinge where it will flex. Then cover this area with a thin amount of wax. You can use ski wax like me or a crayon (which will make things even easier). I
Place the hinges in the aileron, using the marks you made to be sure it's centered.
Put the aileron on the wing, again using the marks to keep the hinges centered. You can lightly pinch the aileron as you slide the hinges into the wing to keep the hinges centered.
Flex the aileron all the way down.....
...then all the way up. This will set the proper gap for the hinge line which will ensure free movement and no undue stress on the hinge.
Place a drop of fresh, thin CA on each leg of the hinge.
Then flip the wing over and place a drop on the top of each leg of the hinge.
It's a good idea to go over the servo mounts with a little bit of extra CA for reinforcement...
...as well as the mounting tabs and anti-rotation dowels.
Unfortunately the S9070SB servos need to have the mounts enlarged slightly. Hitec 5245 or 7245 servos will drop right in of course.
Remove the stock arms from the aileron servos...
...install the rubber grommets in the mounting eyelets...
and install the steel eyelets in the grommets as shown.
Pop the servo into the mount with the output shaft forward. Drill out the servo screw holes...I am using a Great Planes Dead-Center hole locator to do this, which is a super handy tool.
Install the servo screws...
...then take everything back out again and put a drop of thin CA onto each screw hole to reinforce it.
Get all the hardware for the aileron linkage together...that's two short pushrods, the two second-longest servo arms from the Du-Bro super-strength servo arm set, four ball links, and four 2mm screws with nuts and washers (not shown).
Put the servo arm on the servo and center the servo with your sub-trim.
Lock the aileron to neutral with a piece of tape.
Screw the ball links onto the pushrod until the length is right.
Assemble the ball link to the servo arm. Screw the other ball link to the horn, making sure to use a little thread locking compound everywhere.
Get all of the hardware together for the landing gear.
Grind a notch or flat spot into the end of the axle for the set screw on the wheel collar.
Install the wheel onto the axle with the wheel collar and a little thread locking compound.
Tighten the axle onto the gear leg with the inner face of the wheel pant captured between the axle and the gear leg.
Repeat the process on the other wheel.
Drill a hole in the wheelpant through the hole in the gear leg for the wheel pant attachment screw (short Phillip's head)
Drive the screw into the wheel pant
Remove the screw and add a drop of CA to the hole to harden up the newly formed threads. Reinstall the screw and set the landing gear aside.
Now let's turn to the fuselage. Put some thin CA over any exposed glue joints on the motorbox to reinforce them a little.
Do the same on the battery tray and any high-stress joints you can reach with your CA bottle.
Place the landing gear on the fuselage.
Prepare the landing gear bolts, putting a washer on each one...
...and a drop of thread-locking compound.
Install the landing gear.
Now let's tackle the most important and fussiest part of any small ARF build, installing the elevator. First install the horn in the elevator as shown, in the exact same process as the ailerons. Remember to use the shortened horn on the elevator.
Do the rudder too as long as you've got the epoxy mixed.
Now flip the elevator over and slide it into the fuselage slot. You'll have to put it in at 45 degrees or so first...
....then push it all the way in...
....then finally flip it over upright.
Now slip the stab in.
Install the hinges like you did on the ailerons. Flex the elevator all the way and then all the way down to ensure a proper gap and then put four drops of glue on each hinge.
Measure the distance at the front of the stab from the fuse to the tip on both sides to make sure that the front edge of the stab is centered in the fuselage. Place a piece of tape on the leading edge of the stab to mark where center should be.
When everything is lined up to the wing tube, wick some thin CA into the joint between fuse and stab on the OPPOSITE side of the tape. Once that's cured, take the tape off. Then go around all four joints and wick in more glue and let it cure.
Line the rudder hinge centerlines up, and install the rudder just like you did on the ailerons and elevator. Flex the rudder back and forth to set the proper gap.
Apply four drops of CA to each rudder hinge and let it cure.
Now let's install the tailwheel. Flip the fuselage over.
First disassemble the tailwheel by loosening the shaft collars.
Grind a flat spot on the tailwheel shaft so that it doesn't slip in the tiller arm.
Also grind a flatspot on the axle where the collar for the wheel goes.
Reassemble everything, adding thread-locking compound on every fastener.
Tape the tailwheel assembly to the fuselage with the pivot point directly over the hinge line.
Drill two holes in the wood where the screws go to fasten the carbon fiber leaf to the fuselage.
Install the screws into wood. Loosen the grub screw on the tiller arm and swing the wheel out of the way, then drill a hole in the rudder for the tiller screw attachment.
Install the screw for the tiller arm as well.
Remove all three screws, take the tailwheel assembly off, and harden all holes with a drop of CA.
Reinstall everything and ensure that it's sturdy and the tailwheel follows the motion of the rudder smoothly with no binding.
Now let's install the servos for the ruder and elevator. First remove the covering on the hole for the rudder servo.
Again I had to enlarge the openings slightly to get the S9070's to fit. After cutting away the interfering wood, run some thin CA along the edges to grab the covering and seal the wood.
Put the extensions on the servos.
Add some heatshrink tubing to the connections to keep them secure.
Heat it up with a heat gun to shrink it.
You can use an old piece of pull-pull wire to guide and pull the extensions through the fuselage.
If you run the wires through the formers and bracing like this, they won't flop around.
Run the wires through the guide holes in the air dam and canopy bulkhead.
Install the servos just like you did on the ailerons.
On both the rudder and elevator I was able to use the second hole in on the long Du-Bro servo arms. I was able to get plenty of throw on both the rudder and elevator.
Enlarged elevator servo opening
Elevator servo installed
Plenty of throw with ~140% ATV...
...this is an EXP after all! By moving the link in one hole on the servo arm you reduce the stress on the servo, increase your available resolution, and increase your power to the surface. Proper set-up is key!
Next let's get the motor ready for mounting.
Take the grub screw out of the provided shaft collar...
And put a drop of thread locking compound on it.
Put it on the back of the motor being sure to align the flatspot of the shaft with the screw.
Put the X-mount on the back of the motor with the countersunk (conical) screw holes out.
Put some thread locking compound on the included countersunk screws...
...and install them in the motor.
Put the bolt-on prop adapter on the motor.
Screw it on with the included allen-head screws. Put a little thread locker on each of them.
Line the motor up on the firewall. If you are using the 4016T-500 V2 you will not need any spacers or anything. If you are using a different motor the kit includes some X-shaped spacers.
Put some thread locker on the mounting screws...
...and tighten them onto the firewall.
Next I am going to prepare the Airboss 80 ESC for use with a separate BEC. Start by removing the shrink wrap on the connector. If you are using 6V servos, skip this step! Just plug and play and you'll be fine.
I like to use this Spot-On solder jig. Very handy.
Desolder the wires from the connector. You can do these one at a time so you know you'll get the polarity right.
Take one input wire from the BEC and slip a piece of heatshrink over it and the power wire for the ESC and solder both back to the connector. Tighten the heatshrink then do the other leg of the ESC/BEC.
It's essential to not connect the power from the Airboss' built-in BEC if you are using another power source. You can either remove the red wire from the ESC itself or you can make a custom extension like I am doing.
After splitting the three wires of the extension, lift the keeper tab on the shell of the connector and remove the terminal from the male side...
As well as the female side.
Now that you have an extension that only has the white and black (signal and ground) connections, twist it gently to keep the wire neat.
Connect it to your ESC...
...and secure with a piece of heatshrink.
Unfortunately the switch in the Airboss will no longer be functional so you can remove it and cover the ends with a piece of heathrink. The system will be live as soon as you plug in a battery.
Mount the ESC to the bottom of the motor box. I used a piece of 3M Dual-Loc...
...as well as a loop of velcro. For the bullets, I have had bullets come apart as well as wear through the heatshrink and short in the past after hundreds of hard flights, so on this build I decided to mount all wires so that this could not happen.
It's a good idea to cover any edges that wires cross over with a piece of fuel tubing to prevent chafing.
Now let's mount the cowl. Cut some pieces of cardboard or plastic that cover the mounting tabs and tape them to the fuselage.
Slip the cowl on so that the cardboard pieces go over it and let you know where they are under the cowl.
In order to get proper positioning and clearance we will need to install the spinner. You will need the thin spacer to get the proper fit to the shaft of the Torque.
I used some folded up pieces of tape as shims to get the right clearance against the cowl.
Slip the cowl on then install the spinner. I used a part of the collet adapter to get the prop adapter nut to press on the spinner backplate.
Check to make sure the spinner gap is correct.
Align the cowl to the spinner backplate as well as the stripes on the fuselage and tape it in place.
Then drill some holes through the cardboard pieces as well as cowl and the wood tabs.
Install the screws through the cowl and the tabs.
Now take everything off. If you did it right the holes should be perfectly located.
Add a drop of thin CA to the holes to harden the threads.
Reinstall everything...and that spinner gap is perfect!
Now it's time to the start the radio install. I used a piece of 3M dual-loc and a loop of velcro to fasten the BEC.
More dual-loc for the receiver.
There is a convenient slot around the receiver tray for a zip-tie. I always run zip-ties for soft mounting through a small length of fuel tubing to isolate from vibration.
All the wires are properly secured. I used the foam wire keepers available from Spot-On RC (Aztech Aeromodels) to keep everything secure. If you want to fly hard and keep your planes in one piece having secure wiring is a must!
I used two pieces of black pinstriping tape on the bottom of the wing to mark where the CG is. That way you can feel it but not see it when you want to check the CG.
This is where my battery ended up for the correct CG.
Anywhere you put down self-adhesive things like Velcro or tape, spread some UHU POR or Welder's glue and let it dry. Contact adhesive grabs these glues tenaciously. This is especially important on the battery tray.
Next let's open the bottom of the fuselage for cooling air to escape.
First trim away the covering about 1/8" shy of the edges of the wood and then fold those edges up and seal them to the wood with your iron.
This is what the vent should look like when done properly.
Next I decided to seal the hinge gaps. This is totally optional. In some cases it improves roll rate, in some cases it makes it more consistent, and in some cases it does nothing at all. It always looks better though!
Cut a strip of Ultracote the length of the hinge line, about 1/2" wide, and crease it down the middle.
Drop the covering into the hinge gap with the surface totally deflected.
Slowly and carefully seal the covering down with the covering iron. Go slowly, tack it in a few places, then go back over everything and it will look SWEET.
I also did the elevator hinge line...the same process, but using a thinner (3/8" or so) strip.
Next let's apply the decals...first cut them all out. Try to avoid sharp corners as they may lift.
Position the decal on the surface...
Then spray the surface with Windex. I have found that genuine Windex works better than generic stuff here for some reason.
Place the decal over the Windex and slide it into position.
Use a soft cloth to squeegee out all of the Windex and any bubbles.
Let it sit for 12 hours to dry and you'll have a great looking graphic.
Same process on the fuselage decals...
And this decal on the hatch.
Doesn't that look sick!?
Extreme Flight Green MXS Unboxed
B and E did some graphics I designed for my new mxs.
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