B-24 DTFB design and build log

[thenated0g]

B-24 DTFB **update: It flies. now w/plans

A couple months ago my friend had linked me to nerdnic's videos about designing foam board planes like Flitetest does them. I finally got around to watching them all (3 hours!) and started looking around for something to try out. I quickly found this great balsa plans site: http://www.outerzone.co.uk

After combing thru plans for an hour or so i had a few that i liked and the one i decided to try was a set of b-24 plans found here:http://www.outerzone.co.uk/plan_details.asp?ID=6706

Using inkscape i dropped in the power pod pdf and sized the plans to match the same scale. That is, that the fuselage will have a similar size as viewed from the front as swappable would. I believe this will give me a close scale look for some small motors to be installed on the wings.

Inkscape makes it very easy to adjust your shapes to match any contour so it went fairly quickly. The hard part is figuring out how the foam with meet up and glue together. As i found in my first build there are definitely "better" ways to make parts connect.

Just thought i would share my current status and pics. I will update as i get things done.



With current build i was not too concerned with making the shape perfect. For instance i didn't want to worry about how the wing would slide thru the body so i just left a rectangle cutout for easy wing testing. The tail i printed out per the balsa plans, but in reality i think trying to get a split elevator will add to much difficulty to the build. I did end up cutting and installing the former's for the top and nose so that i could see if the curvature looked ok and if they even were printing out correctly. And as i am reminded every time i build a flitetest plane, i really don't know what i am doing with construction paper. None of this mattered after i had my successful free flight tosses though!

Current weight of the frame is about 230g
Wingspan: 47"
Fuselage length: 26"

Now that i have finished the glide tests i need to get some electronics. I am currently planning on a 2s setup.
4x 1806 motors 2280kv
5030 3 blade props
12a esc's
1000-2000mah 2s
3x 8g servos. No rudder as it will have differential thrust.

I expect the flying weight be in the 500-600g range and if i keep the throttle down i expect 5 minutes on a 1000mah battery.

And i need to figure out the landing gear.
And adjust the body so the wing goes thru it, like the FTspitfire.



In this video the wind was coming from the left and each throw i was adjusting the weight back slightly.

update 8/20/2015

 

[nerdnic]

Great work so far!

 

[Rasterize]

Awesome!
Love the B-24! There are so few builds of this bird. Much less one that is relatively easy to do. I'm really liking your approach to this. Can't wait for the plans! Keep it up!

How about something like this for the rudders later.
View attachment 51723

 

[thenated0g]

Great work so far!

Thanks man. Its definitely not an easy process but pretty fun. I have been following flitetest from the beginning but the design process was always like "magic". Your little series really opened my eyes and now i think about designing stuff like non stop lol

While i wait for electronics I already have another plane for combat i want to work on based off of the Yokosuka MXY7 suicide bomber.

 

[thenated0g]

Awesome!
Love the B-24! There are so few builds of this bird. Much less one that is relatively easy to do. I'm really liking your approach to this. Can't wait for the plans! Keep it up!

How about something like this for the rudders later.
View attachment 51723

Awesome thanks. I will check that out. I think the easiest thing will just be to mod the back of the fuselage so the elevator can be full length and have a little room to deflect down.

 

[thenated0g]

Electronics installed

I ordered the electronics and got them installed. The plane is ready for first crash.

I modified the tail to have a one piece elevator and removed some of the back fuselage to allow it to have full movement.


For the motor pods i already had some Flitetest mini firewalls so i sized the pods to match them. They are 5 inches long. The B24 blades are offset slightly so that from the front the blades overlap, but from the top you can see they will not hit. Also the real plane's motors all spun in the same direction so i did the same.


Pods Installed and i have began wiring in the 12a emax esc's. Each wing will be on its own channel for differential thrust.


Emax 1806 2150kv motors installed. Also began playing with landing gear. I am using 2mm piano steel from grainger.com. 2" wheels in back. 1" in front.


1000mah 3s battery in a temp spot. That gets cg at 30%. Props used are 5030x3.


Heres a video of my differential thrust test.
https://instagram.com/p/6Trd3IRbBQ/?taken-by=thenated0g

 

[Allenhat]

Looking nice. Looking forward to see the finished bird.

Subscribed!

 

[thenated0g]

As a bonus, when you destroy your b-24 you can build a mini quad lol

 

[Jaxx]

Awesome work! Very inspiring.

 

[thenated0g]

Tomorrow is the AMA's National Aeronautical day and i am going to be hitting one of the local clubs, http://www.clearlakemodelers.com.

Since they have a nice runway and i usually fly at parks i figured i would do the maiden with them. Figured i should pretty it up a little so i threw on some sharpie graphics and added some black weathering with my airbrush. The two pictures were taken under different types of lights. The first pic is more accurate to the khaki paint i used. I sometimes get the "why do you put that much effort into foam planes" from my friends. Honestly i really enjoy the building process. Plus you dont learn and get better at things by Not Doing something. This was probably 30 minutes of my evening using a silver and black sharpie stuffed in the back of some drawer and about 1/4 of a 0.50 cent paint bottle from the crafts section in walmart with an equal amount of windex. Basically no cost. And if i totally destroy this plane tomorrow i get to build another one

 

[Foam Addict]

Really cool! That looks awesome with some paint on it, not to mention your weathering is perfect!

 

[Jaxx]

It does look really good with the paint! Did you use an airbrush to paint the entire plane?

 

[gabrielete]

Fantastic, that paint job is amazing.

 

[Michael9865]

Nice paint job. I hope you get many happy flights and smooth landings.

 

[thenated0g]

It does look really good with the paint! Did you use an airbrush to paint the entire plane?

Minwax, spray paint first.

 

[ClearSkiesCalmWinds]

Hope you consider sharing your plans. Great stuff. Interested in how you set up your electronics. Cheers!

 

[thenated0g]

Hope you consider sharing your plans. Great stuff. Interested in how you set up your electronics. Cheers!

Already have them. Just need to make a couple adjustments and Mark cg.

Here's maiden flight.

I went thru 2 batteries and it flies great. Almost no trim needed.

 

[Spastickitten]

Did you paint the blade tips yellow? It is a small detail, but it is my favorite

 

[rdallaire]

This plane looks amazing! Really like the weathered look on the paint job too.

As a bonus, when you destroy your b-24 you can build a mini quad lol

Will be expecting plans for the DTFB quad in the future.

 

[thenated0g]

Plans ready for download

warning: These are my first plans ever. Some assembly required! What i mean is this is not going to be a perfectly fitting plan. Some adjustments will be needed here and their. It flies great don't get me wrong. But i am moving on to other things and don't really have the time to make this perfect. Feel free to mod and change as you like. I also am really bad at the cardboard top pieces so i didn't even attempt to post them.

Build notes: I went with a general flitetest style build on pretty much everything.

Wings: Wing spar in the middle and do a spitfire style fold over wing. I left put 2 dihedral gauges/spars on the plans. On my b-24 i slid these inside each wing on each side of the support spar to get the correct dihedral. I glued my wings into the body, but im sure you could work out how to make them removal. The aileron servos go in exactly like the spitfire and other flitetest planes.

Wing holes in body: These are not going to match your wings exactly. I would recommend that you trace your wing halves before gluing them together. The important thing is to get them straight and level. Match your wing half with the bottom of the shape on the fuselage and also match up the very rear part of the wing with the rear most part of the cutout.

Wing CG: 30% of the root chord. This comes out to around 2" from leading edge. Easiest way is to put your fingers on the spar holes closest to the fuselage and slide them forward until they are just off of the holes. With one servo in the tail i was able to get cg with a 1000mah 3s an inch back from the nose.

Fuselage: Pretty standard flitetest construction. For the nose and top you can either use the formers and holes i made and use some construction paper or you can take the paper off one side of some foam and make the bend gently with your fingers. I cut a hole under the wings and put my electronics in that area.

Tail: I went with elevator control only with the servo just under it towards the leading edge. See pictures.

Landing gear: 2mm piano wire steel with 2" wheels in back and 1" in front. I made them slightly taller than scale to deal with grass. The original plane did not have steerable wheels. It was steered by engine and brakes.

Electronics: 1806 2300kv motors, 5030x3 props, 12amp esc, 1000mah 3s (but would run great on 2s).
The above setup is crazy overpowered on 3s. 1,600g thrust on a 7-800g plane. I did a straight up hover on my first flight.
Also with differential thrust you can do some insane donuts while taxiing.

View attachment B-24 Fuselage v2.pdf
View attachment B-24 Wings v2.pdf

The maiden video wasn't very great as i was at an ama club and it was my first time at a club and it was a maiden in front of like 40 people, so want really thinking about stuff much. Will get some better video up here soon.