B-25 Mitchell 60”

[noahangel11]

Hello. I am creating this thread to log the assembly of a B-25 Mitchell that I designed in Fusion 360 Cad software. I used some vintage plans off of AeroFred to get the basic shape of the plane and help me decide on former placement.
I already built a prototype and flew it, this is my attempt to document the assembly as a set of instructions.

Note: The builder should be familiar with Master Series foam shaping techniques. I will not cover that here, as there are plenty of FT videos on those techniques.

NOTE: Thea instructions reference part labels thy are laser etched into the part. Of you are hand cutting parts out from templates made from the plans, it is assumed that you transferred the labels when you cut the parts out. A lot of the instructions reference a part side by the location of the label.

Plans and an instruction manual that mimic this forum posts instructions can be downloaded on my web page and include full size and tiled pdfs:

Rc-skunkworks

rc-skunkworks.godaddysites.com

I will also try attaching them to a post here.
DISCLAIMER: I have not tried assembling the split prints. Print all at your own risk. I would try one page first.

Specifications:
Wingspan - 60”
Motors - qty 2: Flite Test Power Pack C Radials
ESC - qty 2: FT 30A ESC
Props - qty 2: 8”x4.5” 3-blade props
Battery - 3000mah 4S LIPO

Additional materials besides the electronics that you will need:

Qty 10 sheets DTFB

1 sheet of 1/8”x12”x24” plywood to cut out the wing spar pieces.
link to plywood
https://www.hobbylobby.com/Crafts-Hobbies/Wood-Crafting/Unfinished-Wood/Craft-Plywood---1-8"-x-12"-x-24"/p/72081

Qty 8 neodymium magnets. I bought the 8mm ones from Home Depot, and that’s what I cut the magnet mount holes for in the formers.
Link to magnets
https://www.homedepot.com/p/Master-...th-Magnet-Discs-10-per-Pack-07045HD/202526363

Qty 2 control rod tubes and control rods. I use the same ones FT uses on their kits, and the same diameter pushrod wire.
https://store.flitetest.com/push-rods-8-pack-23/

Qty 4 flap control horns. I use the FT ones you can buy in their store:
https://store.flitetest.com/ft-control-horn-20-pieces/

 

[noahangel11]

Here is a link to the maiden flight. I have made minor revisions and am currently assembling a second one for the sole purpose of documenting the assembly for you, and so I can paint it and design decals for it, and to add a new plane to my hangar.

 

[noahangel11]

I started the build with the nose and canopy section of the fuselage. The nose slides off of the battery tray to get access to the battery, and is held on with 8mm magnets. Find all the formers with designations of:
Nose, F1A, F1B, F2 Qty2, F3A qty 2, F3AF, F3AR, F3B, F3C, the skins labels F1-F2, F2-F3, and the Battery tray pictured designated with an A fold.

 

[noahangel11]

Glue F1A on top of F1B, making sure to align the tick marks at the top and bottom of the formers. F1B has the rectangle hole in it to fit the battery tray.

NOTE: the battery tray will be used to assemble and align the nose formers and skins. The battery tray does NOT GLUE to any of the F1-F3A formers.

 

[noahangel11]

Use a bbq Skewer or similar item to pick out the foam circles on F3AR, leaving the paper on the back side of the piece. Glue in 2 of the 8mm Neodymium magnets into the holes. Next glue F3AF to the top of F3AR, sandwiching the magnets.

 

[noahangel11]

One of the F3A formers has magnet holes in it. Dig out the foam leaving the paper on the back side, and glue in 2 8mm neodymium magnets. Then sandwich glue the F3A without magnet holes on top of it.

 

[noahangel11]

Next place the assembled F3A formers flat on the table with the side that has the magnets in it facing up. Also place the F3AF and F3AR assembly above it, with F3AR that holds the magnets facing up.
Take the F3B former and remove the foam from the 4 magnet holes, leaving the paper on the back side.
The nose of the plane separates between F3A formers and the F3B former.

If you place F3B on top of Both F3A former assemblies, with the magnet holes in F3B facing up, you can now glue in the 4 F3B magnets and ENSURE that the polarity of the magnets will be correct to grab onto the F3A formers.

 

[noahangel11]

Begin to shape the first skin labeled F1-F2 by removing the paper off of the side that has the label on it. Shape the piece on the edge of a desk into a circle and glue the ends together to make the skin. I like to use masking tape to hold pieces together as they glue. Once the glue is dry, inset assembly former F1A/F1B into the skin, lining up the top and bottom tick marks on the formers with the top and bottom marks on the skin. F1 fits into the narrower end of the skin.

NOTE: all my formers are labeled so that when the label text is upright, that is how it is oriented in the fuselage. All the skins, with the exception of 2 on the engine nacelles, will always have their seams where they glue together at the bottom of the former, and the bottom of the plane.

F1A sticks out of the skin, and F1B glues to the skin. This leaves a lip for the nose to glue to.

 

[noahangel11]

Take the battery tray and score the lines with the dull side of a razor, then break out the strips of foam that were marked for removal on the plans. Leave the paper on the back side. Apply glue on the slots and perform an A fold to glue the battery tray sides up. In an A fold, the sides sit above the middle piece.

 

[Ligbaer]

Take the battery tray and score the lines with the dull side of a razor, then break out the strips of foam that were marked for removal on the plans. Leave the paper on the back side. Apply glue on the slots and perform an A fold to glue the battery tray sides up. In an A fold, the sides sit above the middle piece.

would you recommend this as a first ms style build, i've always liked the b-25

 

[noahangel11]

Place the battery tray into the F1B former slot, Through the skin. Orient the tray so the open end faces up and the close end faces the seam in the F1-F2 skin (the bottom of the plane).
DO NOT GLUE!!!!!!!!

For the front section of the fuselage we are only using the battery tray as a guide for gluing formers onto the skins.

 

[noahangel11]

would you recommend this as a first ms style build, i've always liked the b-25

I would recommend maybe the FT MS Corsair, not the mini. . It is a crossover model between traditional build techniques and the MS techniques. It’s a good flyer and the plans are available. I will say this B-25 plane flies well and is only slightly harder to build. My fit of parts will not have the precision that FT kits have. I’m just a guy in my basement tinkering Lol. But my plane does go together pretty nicely. Maybe just some minor fit issues to trim as you go.

 

[noahangel11]

If you have not already done so, glue the 2 F2 formers together and then slide the former onto the battery tray, making sure the bottom of the former faces the F1-F2 skin seam. Use the tick marks on the former to fit the former into the skin, lining up the marks on the skin and the bottom seam. Make sure the former fits half way into the skin, leaving a lip on F2 for the next skin. When happy with the fit, glue the former to the skin.

NOTE: DO NOT GLUE F2 to the battery tray. Remember, the tray is only being used temporarily for alignment.
If the fit is a little tight, try rolling the edge of F2 along the bench to flatten it a little. It’s better to be slightly loose that too tight a fit, and a corner of the skin getting compressed too much.

 

[noahangel11]

Temporarily pull out the battery tray from the nose assembly. Take the paper off of the label side of skin F2-F3, and shape it to a circle, glue the edges together. Fit the narrow end of the skin onto F2, making sure to align the bottom seam to the F1-F2 bottom seam and the top tick mark with the former top tick mark. When happy with the fit, glue in place. If the fit of the skin onto the former is tight, don’t be afraid to slightly trim the F2 corners, or add a slight bevel cut to either piece to get it to go. After the glue dries, reinsert the battery tray onto the nose and onto F1. We will use it for aligning F3A former.

 

[noahangel11]

Slide the F3A former assembly onto the battery tray.

NOTE: the F3A side with the magnets in it needs to be facing up like the pictures shows, towards the tail of the plane.
when happy with the fit, glue F3A ALL THE WAY FLUSH INTO F2-F3 SKIN. DO NOT GLUE F3A TO THE BATTERY TRAY.

F3A is the separation point for the nose from the rest of the fuselage so the skin should be flush. if you need to, roll the former against the desk to make it fit easier.

 

[noahangel11]

Slide F3B/F3C assembly onto the battery tray, with F3B facing down, so the magnets are facing down and mate up with the magnets on former F3A assembly. If you did the magnet gluing steps correctly, polarity will be right and the formers will stick together. You can also stick former assy F3AF/F4AR to the front of F3B former like the picture shows. This small former flies into the canopy layer.

Make sure the battery tray is still sitting all the way into the nose. DO GLUE former F3B/C to the battery tray.

 

[noahangel11]

Well that’s all I can do for tonight, will try to add more content tomorrow evening.

 

[SSgt Duramax]

It gets exhausting writing these huh? Plane looks good! I may have to add it to my list!

 

[Flightspeed]

Wow. This is probably my favorite master series plane I’ve seen. Definitely not biased by the fact I absolutely the b 25 😉

 

[Ligbaer]

Wow. This is probably my favorite master series plane I’ve seen. Definitely not biased by the fact I absolutely the b 25 😉

when i build one im gonna make it the ruptured duck