CMAD Miss Foxy Lady build thread

[KRProton]

I use the threaded holes in the elevator joiner to guide a 3/32" drill for drilling the holes through the elevators for the mounting screws. The drill fits perfectly through the threaded holes causing concern for potentially drilling away some of the threads in the joiner, but I've done it this way on all the MFLs (and other Q40s) I've built, and the screws thread into the joiner securely. This is the best way I know to make certain the holes and the screws will align with the joiner and the screws will be flush with the top of the elevators.

With the elevator joiner installed in the correct orientation and centered equally in both stab halves, and the stab halves tightly taped to the fuselage, place a 3/32" drill in one of the threaded screw holes. Note the angle of the drill. When actually drilling the first hole next, the angle of the hole will partly keep the drill at the correct angle, but keep this angle in mind as well -- sligtly forward and perpendicular to the top surface of the elevator.

Tightly holding the elevator joiner into the slot in the elevator, and holding a wood block to the top of the elevator over the location where the drill will come through, drill the hole through the elevator keeping the correct angle.

Remove the elevator from the fuselage. Enlarge the 3/32" hole with a 1/8" drill. Holding a countersink by hand, proceed incrementally to cut a small countersinl in the top of the elevator for the screw.

Test-fit the screw and elnarge the countersink if necessary. Temporarily fasten the joiner with one of the screws.


Re do the the steps for the 2nd hole in the other side, but leave the joiner fastened to the first elevator as you go.

[KRProton]

Once you have both elevators fastened to the joiner, double-check that you are getting a good 1/4" of up elevator deflection and 1/8" down elevator. Make any adjustments as needed.

View the alignment of the elevators to the stabilizers from behind the model. Make sure that both elevators are centered and align with the stabilizers. If necessary, remove the joiner and use a couple crescent wrenches to "tweak" the joiner as necessary to perfect elevator alignment. Sometimes this takes me a dozen or so attempts, but sometimes I get it on the first try as I did on this model.

[KRProton]

A few more words about the elevator joiner before proceeding;

On the 2nd MFL that I am building, I found that the joiner wouldn't quite fit into the pockets on the elevators. You don't want to force them.

I used a metal file to trim both edges to make the joiner a bit narrower to fit.

Now the elevator joiner fits into the pockets as it should.

[KRProton]

On this 2nd MFL, I also found that the joiner was longer than the joiner on the first MFL preventing the stabs from fitting all the way to the fuselage.

I used the dremel tool shown to carefully elongate the pockets in both elevators.

Now the elevators properly can fit all the way to the fuselage.

[KRProton]

For the Jett engine setup, I like to mount the battery in the nose to help achieve the correct C.G. without having to add any nose ballast. With the battery in the nose, most of my MFLs need fractions of an ounce in the tail to balance where I like. If at all possible, I strive to avoid adding nose weight because more is required to affect the C.G. Plus, adding weight in the nose is usually a hassle because the only place to put it is in the engine compartment which usually (never) works out well, because weight seems to come unglued due to fuel and vibration. So, if at all possible, build a slightly nose-heavy plane so only tail ballast will be required.

I make my own battery plate from 1/8" lite-ply. The edges are beveled to match the curvature of the fuselage as best as i can. I also sand a bevel to the front edge of the slot for the throttle cut guide tube.

On the top of the battery plate I glue a piece of velcro for attaching the battery. Usually, I use a 700mAh - 900mAh 2S LiFe battery, but this 500mAh one was provided for this build.

[KRProton]

I install the battery mount plate and temporarily hold it in place with a piece of foam.

View the battery plate from behind and make sure it is level.

I'll use a little thin CA on both sides of the battery plate to tentatively hold it in place, then remove the foam. Then securely glue the battery plate in place with thin CA on the top and bottom. You may also follow wiht a fillet of medium CA too.

[KRProton]

This is my own custom servo tray from 1/8" birch ply. I glue the servo screw doublers to the bottom of the tray and, same as the battery plate, I sand a slight bevel to the edges of the servo tray to fit the fuselage a bit better.

I went to my scrap collection to find a piece of wire and tube that can be used a pushrod fo rthe an on/off switch. Here, I used a piece of .047" wire and tubing from a DuBro No. 922 .047" Micro Push Rod system.

Drill a similar-size hole through the side of the switch that will fit the wire.

Make a 90-degree bend on the outside end of the wire to be used as a small "handle" to turn the switch on and off from outside the fuselage. With the switch installed on the servo tray, mark the location where to make the 2nd bend in the wire.

Slide the"bearing tube" onto the switch pushrod, make the bend at your mark, then cut the wire long enough so it will protrude through the switch a good 1/8" or so as shown.


We'll get to fuel tank and servo tray installation when I check back in.

[KRProton]

The wing bolt hold down plates in the fuselage appear to be 1/8" aircraft plywood. As a personal preference, i like to double this up with another layer of 1/8" birch ply. I've never seen or heard of this being necessary, it's just my personal preference to give a little more bite for the nylon wing bolts;

The doublers will be glued to the top of the existing wing bolt plates in the locations shown. Test-fit first to make sure they doublers fit. Trim the doublers wherever necessary.

Sand a bevel to the inner, top surface of the forward doublers. This will help accommodate fuel tank inistallation.

Glue the forward, then the aft doublers into place. I use medium CA, but work quickly. Once the doublers contact the top of the wing bolt plates already in place, they seem to stick immediately, so there will be little time to get them positioned perfectly.

Here's the doublers glued to the tops of the existing wing bolt plates. Now you should have the common 1/4" of material for the bolts to bite into after you drill the holes and tap the threads later.

[KRProton]

This is my fuel tank setup. The "wedge" system has been explained in one of the first few posts in this build thread. To reiterate, this "mechanical" fuel tank mounting method is secure and repeatable, but not everybody may prefer this method. And also, I did not invent this method. It was developed by Dub Jett and others.

I wrap the aft end of the tank with two layers or kapton tape which is an anti-abrasive tape made for the electronics industry. It will ensure that the cradle will not wear into the tank.

Glue the four pieces of the wedge together and the three pieces of the cradle. The inner two layers are 1/8" balsa and the outer layers are birch ply. The balsa pegs line it all up. Once aligned, I just glue it from the outside with thin CA.

On the cradle, the balsa pieces are on the outside and the birch ply is in the middle. Do not apply glue at the top of the wedge where the wedge fits. Once the pieces are tentatively joined, cut the top of the cradle where the wedge will fit. Now securely glue all the parts of the cradle with more thin CA.

[KRProton]

Test-fit the parts of the cradle. Make any adjustments necessary so they fit together without too much interference.

Test-fit the tank into the cradle/wedge assembly. Note that the top of the tank is as labeled by the sticker on the tank - but this may not be the EXACT top...

The tank will be correctly aligned when the label reading "TOP" is toward the top of the fuselage and the seam at the back of the tank is vertical as shown in the photo. This orientation is not critical, but is determined by any small amount of curvature that may be in the pickup line inside the tank. Another way to confirm that the tank is positioned correctly is to be sure that the pressure line will be located on the right side of the fuselage (the same side of the fuselage as the head of the engine). (It is desirable to have any curvature that may be in the pickup line inside the tank facing downward to prevent the engine from sucking in any errant air bubbles.)

Glue the wedge to the top of the tank, again, aligned and centered over the seam. I prefer Shoe Goo because it adheres extremely well, yet the wedge may still be removed if ever necessary. It takes at least a few hours for the Shoe Goo to harden, overnight to be safe.

Here's another look at the wedge aligned with the seam after being glued into place.

[KRProton]

Here's another look at the wedge aligned and centered over the top of the tank.

To be sure the wedge doesn't shift while the glue is drying, prop it up so it will not rotate or move possibly allowing the wedge to slip until the glue dries.

[KRProton]

I forgot to add the 1/8" ply spacers to the top of the servo tray to raise the throttle cut servo just for a bit more clearrance between the elevator servo.

I know from building previous Miss Foxy Ladies that, to end up with a finished model that is just a smidge nose-heavy (or at least for sure not tail-heavy), balancing no farther aft than 2-15/16" back from the leading edge of the wing at the middle, the front of the servos needs to be 5-1/4" back from the front of the wing saddle in the fuselage. However, since the receiver battery provided for this model is smaller than ones I typically use, I'm going to mount the servo tray 1/4" farther forward just to make sure I don't need any nose weight on this model. I taped a small ruler square to another small ruler to make a gage for where to place the servo tray and therefore the front of the sevos.

Temporarily position the fuel tank with the cradle and wedge into place just to see how it fits. When gluing in the cradle later to set the location of the tank, we want a good 1/8" clearance between the back of the tank and the front of the servo tray as shown here.

[KRProton]

Because the aileron servo is positioned on the top of the wing, there is potential for the aileron torque rods, pushrods and/or the ailreon servo itself to interfere with the servos in the tray. For this reason, mounting the aileron servo below the top surface of the wing will help to make sure there will be enough clearance. We will get to aileron servo mounting later when we move onto the wing. However, it is also a good idea to get the servo tray in the fuselage as high as possible to ensure this separation. However, the higher the servo tray, the closer the rudder and throttle cut servo must be moved toward the middle of the servo tray because of the curvature of the fuselage up toward the cockpit. But we don't want any of the servo arms/wheels and linkages in the fuselage to interfere with each other. There is a lot to think about here including the height of your servos and the kind of pushrod linkage you use in making sure there is room for everything. It's a bit tight, but with planning there is enough space. With the servos and linkage I use, I know that positioning the servo tray at least 1-5/8" above the wing saddle will help make sure I get this clearance. If you're not sure, you could always hold off on mounting the servo tray until you have the aileron servo mounted in the wing. Then, you can check to see how much clearance you need and how high to mount the servo tray. Herre's a photo of the aileron servo on one of my own MFL wings and how it fits in location to the servos on the servo tray...

This is the aileron servo installation we will be doing later in this build when we get to it.

You may not be able to tell in this photo, but with the wing on the fuselage there is a good 3/8" clearance between the aileron servo and linkage up to the servos in the tray. There will be plenty of room for the servo arms/wheels, pushrods and linkages.

Make sure the servo tray is at least 1-5/8" above the surface of the wing saddle. You can remove material from the sides of the servo tray by sanding to make it narrower allowing it to be positioned higher. Also make sure that the servo cases are not contacting the fuselage.

[KRProton]

When ready to glue in the servo tray, once-and-for-all make sure it is positioned where intended. View the tray from the front making sure it is level.

Mark both sides of the fuselage at the sides and front of the servo tray.

[KRProton]

My method for gluing in the servo tray is to CA strips pf ply or balsa to both sides of the fuselage on top of which the servo tray will fit. These strips can be anythiung from 1/32" plywood to 1/16" balsa and will help keep the servo tray securely locked into place.

Align one of the "locking strips" with one of the lines drawn inside the fuselage noting the location of the servo tray. I use thin CA to glue this strip into position. Then glue the other strip to the other side.

For gluing in the servo tray soon, it will be easier if the servos have been removed. Test-fit the servo tray in the fuselage.