A comprehensive guide to building the LX / Banana Hobby YF-23

[Arcangel]

In preperation to glue the fuselage halves together, we need to add the color back into the inside of the model and touch up those areas that the folks at the factory missed. [ see photos 1 & 2 ]

} Tape off all of the areas that will be your gluing surfaces and spray away.

A personal note, The original color scheme for the YF-23 from BH / LX was dark grey and black. I plan to add a little more color to help give a more scale appearance to the plane and change things up a bit. The colors that will eventually define the model's exhaust troughs are Testors Model Master series : " Jet Exhaust " ; " Steel " ; " Chrome Silver ".

[Arcangel]

It is now time to glue the top and bottom fuselage halves together and get this model back into shape.

} I first made some bag weights to hold down on the model while the glue dried over night. The bags are double stacked plastic sandwich bags filled with 16 oz / 1 pound of bird shot and tied off. [ see photo 1 ]
} I used (1) Velcro loop to hold the forward halves after I applied the glue and stuck them together. [ see photo 2 ]
} I used (10) bags in total on the rear half of the fuse and a whole bunch of 1 1/2 inch " T " pins along the glue seams in the front and back halves to keep things from moving around and hold the seams tighter. [ see photo 3 ]

A personal note, I recently discovered Gorilla Glue Clear and that is now my go to glue for doing high strength joints or large areas. It dries clear with no expanding froth like the original, but still offer lots of strength and gives you plenty of time to work it over larger areas before it starts to harden up. It acts more like a contact cement when it has dried and if you careful enough you can lift and peel away any excess with out damaging the foam. The paint however, is a different story.

[Arcangel]

Now that we have a whole fuselage together, its time to prep for the installation of the V Tails.

} I used my trusty Foam Tac to glue in the mounting tab for the V Tails since it was a small area to work with and is real quick to set when you do that pull apart thing as noted in its instructions. [ see photo 1 ]
} I broke out my favorite filler putty and filled in the glue seams to give her a nicer look. [ see photo 2 ]

[Arcangel]

At this point in time, we need to do a mod and some prep work on the V Tails before gluing them on the fuselage. If you have had any experience in the past with a BH / LX model, then you will be familiar with their high quality construction :Silly: LOL and their YF-23 model seems to be the company's step child for the Q C department. [ see photo 1 ]

} I noticed on my model, the gap between the control surfaces and their counter parts varied from 1/16 inch to 1/8 inch along the hinge lines and up to 3/16 inch of gap clearance for the moving surfaces, so I opted to pull apart all the flight surfaces, remove the pin hinges and redo them later on with cloth hinges or something.
} I added a 1/8 inch foam piece to the bottom of the V Tail control surfaces to fill in the excessive gap clearance and also applied some filler putty to remove the panel lines from the V Tails. [ see photo 2 ]

Side Note : I recently picked up a book that has a lot of good information on the YF-23 and among some of the things I have noticed is that there are quite a few more panel lines on the model than there are on the actual aircraft itself. I honestly don't know if the model designers were just having too much fun or if they decided to take a Revell 1 / 72 scale plastic model kit as their sample to go by. :Confused:
A case in point, there are no panel lines on the actual aircraft's V Tails since they are full flying surfaces covered with carbon fiber laminate skins but the RC model sure has plenty of lines. :Loser: [ refer back to photo 1 ]

[Arcangel]

I was finally able to finish up sanding the V Tails and the rest of the aircraft for that matter, to get them ready for mounting. They turned out better than I had expected and fit really well on a test fit. [ see photo ]

[Arcangel]

I decided that it would be best to mount the wings to the fuse before gluing on the V Tails. Those things have a habit of getting in the way with the stand when you go to lay the main fuse on its side.

} I first prepped the bolt on mounting blocks by hitting them with some 80 grit emery cloth. Remember to clear out any paint that was sprayed in the holes for the wing blocks so that you can get a solid bond. [ see photo 1 ]
} The wings and fuse may have some bulges in the foam, so dry fit them before proceeding and sand them level to your liking to get the best possible fit for your model.
} The peg / stem blocks are first glued into the fuselage and allowed to fully dry before use.

Side Note : I still prefer to use Gorilla Glue on the structural hard points for its strength and gap filling capabilities and Gorilla Glue Clear on the rest of the seams as needed since it does not expand on its own. It does suck to be forced to watch over it for 3 or 4 hours until the glue has setup enough that it can be left unattended. But remember....... T-Pins are your best friend in times like these. :Cool:

} Once the peg blocks are glued in place, we need to cut a sheet of plastic to prevent the glue from the wing mount blocks from leaking down and potentially gluing the wing to the fuse. In the build video from the RC Informer, he suggests using plastic wrap. I prefer to use something a little heavier, so I used a " Heavy Duty " Zip Lock 1 gal bag for my source material. Just cut a large enough patch, 2.00 in square or so, and place the patch on the wing mount block with its hole centered on the patch and cut out the hole. Then place the patch over the fuselage wing peg. [ see photo 2 ]
} At this point it is easier to attach the wing mounting block to the fuse 1 peg at a time starting from the aft of the wing.
} Apply some glue to the mounting block, and apply a thin amount of glue to the mounting block recess and seat the wing on the block. Make sure the alignment post lines up and T-Pin the hell out of the surface into place; top and bottom. This will help reduce the gap in the wing and fuse and allow the back mounting block to dry with as little stress on the peg as possible. [ see photo 3 ]

} When the rear mount has fully dried, repeat the process for the front block and make sure the leading edges align before you T-Pin the front.

[Arcangel]

The next few set of mods I am going to cover are pretty much for cosmetic purposes and to help clean up the aesthetics of the model. None of these mods are intended to increase the model's aerodynamics and are not necessary by any means. They just make the plane look better and take little time to complete.

} I took some foam from a coffee cup and added it to the flaps, the ailerons, and on the wing tips to help fill in the excessive clearance gaps that were cut into the wings. [ see photos 1, 2, & 3 ]
} I added some foam to the trailing edge of the flaps section to fill in the chamfer cut that was put in on the " TOP " side of the wing. I have no idea why it would be there since the model was not originally designed to use flaperons. In any case, it just look bad since the cut for the flaps are much deeper than the ailerons so they had to get some fill put in there. :Confused: [ see photo 4 ]

[Arcangel]

The next item I wanted to address is the rounded out tip on the left forward wing root. [ see photo 1 ]
We all know how Banana Hobby / LX models are known for their OUT STANDING quality in their models, :Silly: LOL so it was no surprise to find such a huge gap in the leading edge of the wing at its root. I'm sure you will find this kind of thing on all the manufacturer's models, but depending on the model you can design it in such a way to minimize its appearance. On the YF-23, not so much and it just looks as though someone took a big chunk out of the leading edge with a broad sword. The funny thing is the opposing wing does not have this issue at all and that is what is frustrating.

} So, we add some more foam to the front wing roots and sand it down accordingly. [ see photos 2 & 3 ]

Side Note : The EPS foam used to make coffee cups are an excellent source to use as add in material for small applications. It will bend around moderate curves very nicely and bonds extremely well with foam safe CA glue while remaining easy to sand and shape.

Edit : 09-01-18

} When your done shaping the foam inserts, there will not be much left on the wings but at least the gap will be a lot less as well. [ see photo 4 ]

[Arcangel]

Now that the wings are taken care of, its time to move on to the V-tails as they are sanded and ready to go.

} During the the test fit of the fixed portion of the tails, I noticed that mine did not fully lay flat on the fuselage surface and had a little gap or just barely brushed the surface where they were to be glued.

} I ended up having to extend the glue channel for the tail brace and do some minor sanding to get a good solid fit and get them to lay flat on the fuse [ as noted in red circle on photo 1 ]

} When you are satisfied with their fit, go ahead and glue them on 1 tail at a time and give them plenty of time for your glue to cure. Use plenty of T-Pins to hold them in place as the fins may need some gentle bending to align the with the fuse [ see photo 2 ]

} The yellow circle high lights just one more area where some foam or sanding filler can be added to fill in more gaps and clean up the model. [ refer back to photo 1 ]

[Arcangel]

I now have Tails on my YF-23 and she's actually starting to look sexy. [ see photo 1 ] :Love:

} When the glue has fully dried / cured, go ahead and lay down some filler putty on the glue seams and sand away to fill in those gaps and clean up the joints. [ see photo 2 ]

[Arcangel]

This next mod I am doing will add a little rigidity to the tails that were just put on and give the V-Tails some added stiffness for good measure. [ see photo 1 ]

} When I removed the crappy stock pin hinges from the fixed tail portions, they got pretty flexible near the tips and was more so than my liking.
Side Note : I doubt the vertical fins on my model would have broken completely off in flight or during some high speed turn, but this mod will ensure all of the fins stay intact and not get wrinkly on me over time.

} I added some single direction, paper thin, carbon fiber laminate sheet cut into strips the full length of the V-Tails. The strips should be tapered cut at 5/32" to 3/16" at its top & 1/4" to 9/32" at its base to accommodate for the taper in the vertical fins. [ see photo 1 ]

} To install on the fins, just draw out your path and with a sharp scalpel or brand new Exacto blade; slice the fins no deeper than 1/4" at the top of the fin and 9/32" at its bottom and insert the laminate strip. Use a thin blade screw driver to push it down into the foam if you need to and make sure it does go below the surface of the fin.

} Now add your favorite foam safe super thin CA glue to the full length of the cut line and put plenty in there to let it soak into the foam and onto the laminate. This way, any excess glue can be wiped off and the polycote finish will help hide any smears on the foam surface. :Cool: [ see photo 2 ]

[Arcangel]

At this point we are almost done with the construction of the model and its time to mount the servos.

} Through trial and error, I have found that the HiTech HS-5055MG metal gear digital servos are a near perfect fit on the BH / LX model EDFs. [ see photo 1 ]
They pretty much drop into the servo plastic mounting boxes with only minor trimming to the side walls to accommodate the servo lead's origin point as noted by the orange circle. [ see photo 2 ]

} The leads need to be trimmed and re pinned for your connectors so that they fit in the channel laid out for the wiring. [ see photo 3 ]

} For linkage I have some ball connectors and push rods left over from a lost FreeWing Mig-21 that will get transplanted to her.

Side Note : One of the flap servos will have to be reprogrammed for reverse in order to make your flaps function properly and you can do this with the HiTech servo reprogramming device or one that is compatible with these type of servos.

[Arcangel]

At long last, the construction of the model is pretty much done and is ready for finishing the foam and painting.

} I plan to put on 2 coats of MinWax Polycrylic along with 2 coats of good old rattle can grey primer alternating between each poly coat The 1st coat was brushed on with a sponge brush and when dried, followed by the primer coat that was sanded with 400 gr paper [ see photo ]

} The 2nd poly coat will be sprayed on and the 2nd primer coat will also be sanded with 400 gr paper.

*** I might apply a third poly coat and primer if it looks like it might be needed. ***

} When all that is completed, a final coat of white primer and a light wet sanding w/ 600 gr paper to smooth things out and she will be ready for color.

Side Note : The next post to follow will have her in color form and we can go from there addressing the small detail stuff that will require minimal effort but add a good visual impact. ;)

[xviper]

I haven't done much with mine for a long time now until about 2 weeks ago when I got an "itch". I decided to remove the stock retracts and install some trailing link ones from my old Mirage and the nose gear from my old FW F/A-18. Both required a lot of foam removal and the nose gear required quite a bit of renovations to the mounting area to accommodate the different gear with the steering rod. Then I got busy building my new FW SU-35 and the L-39 Albatross comes tomorrow. I never expected this to be a quick and easy build, so I tinker with it from time to time when there's no other planes to mess with and when the weather outside is too cold to fly. Since winter is just around the corner, I suspect there will be more days like that.
Next, I plan to run all the servo extensions through the fuse halves before gluing the clam shells together. Maybe I'll have it ready for next spring.

[Alpha]

Retracts look good, those should help tremendously! Other than landing speed, the weak stock retracts were my most worrisome part of this Black Widow.

[xviper]

Retracts look good, those should help tremendously! Other than landing speed, the weak stock retracts were my most worrisome part of this Black Widow.

Do you mean it landed quite fast? Even with full flaps?