Hi there! :) / hot wire fuselage

[cudi]

Hi guys! I'm new to the forum. Just started a new project, which has been bugging me for number of reasons I have some xp in scratch building (balsa and xps foam) but both have always been done in a traditional way (formers + fuselage covering or flat fuselage/magnum type).
But this time I found only 1 plan of B5N2 that isn't too precise, therefore the only option to build this sucker is to cut the styrofoam with hot wire and using formers (I got a nice project in blender, but I've failed with mesh unwrapping in pepakura - I just don't get that software, so XPS is out). I never used this technique so I've go tons of basic questions like: how the hell do I fit my battery and rest of the electronics after I get the fuselage build? Do I cut out slots or a whole compartment?
e.t.c... Any help appreciated

 

[Merv]

...Do I cut out slots or a whole compartment?...

Yes, either way will work, it's the builders choice. The fuse will be lighter if you hollow it out.

 

[cudi]

Unfortunately it seems I'm forced to get back to XPS foam. Cutting styrofoam did in fact stink the whole aparment with nice scent of melted plastic So it seems I have to figure out how to make templates from 3d blender models after all...

 

[cudi]

This is what I have now

Now this is what pepakura does with the wings... Any ideas?

 

[bisco]

wow, that looks sharp!

 

[cudi]

wow, that looks sharp!

Thanks! Let's just hope I figure out or somebody will help me out with pepakura Also I've done an alternative verison of the fuselage.

 

[cudi]

OK, so nobody knows what's going on with this wing, nvm then... Any tutorials on how to cut out a nice fuselage using hot wire (step by step/ dummy resistant)? I found the FT video on the vegan viggen quite inspiring - but how do I cut out symmetrical holes for wings and stabilizers? :O

 

[Pieliker96]

This is what I have now
View attachment 222090
Now this is what pepakura does with the wings... Any ideas?
View attachment 222091

I've had similar stuff happen with unwrapping plugins in google sketchup. My solution is typically to subdivide the mesh into smaller parts which unwrap properly, then join them back together.

OK, so nobody knows what's going on with this wing, nvm then... Any tutorials on how to cut out a nice fuselage using hot wire (step by step/ dummy resistant)? I found the FT video on the vegan viggen quite inspiring - but how do I cut out symmetrical holes for wings and stabilizers? :O

Make sure you've got some method of orienting and locating the formers properly such that they'll be exactly where you want them relative to each other. Once that's done it's pretty easy: just get the hotwire up against the formers and keep it straight relative to the plane you're cutting: for example, when cutting a wing, you wouldn't want the wire to be below the leading edge on one side and above on the other, this would create a divet in the leading edge, most pronounced at half-span.

 

[cudi]

Formers are easy peasy to do, however the wing rib template (the wing root) is killing me I've seen numerous videos how guys do it, but they all seem to do a square shaped fuselage - a round one is not so easy... which is my point

 

[willsonman]

I'd highly suggest you have a review of David's writeup on his viggen...
JA37 Viggen EDF Build log | Flite Test

I think you'd have great success here with fuselage cross-sections. The B6N2 Tenzan is a BEAUTIFUL and sorely underrepresented aircraft in our hobby. Between the belly gun and the REALLY funky flap movement, this one had some interesting engineering choices. Best of luck on your project.

 

[willsonman]

Perhaps a touch off-topic buuuut...
Nakajima B6N2 Tenzan_EA | Knife Edge Forums

 

[cudi]

I'd highly suggest you have a review of David's writeup on his viggen...
JA37 Viggen EDF Build log | Flite Test

So the procedure I have used was wrong as it seems... The schematic for viggen states more or less that #1 Cut the side profile including wing and tail control surfaces holes #2 Slice the whole thing into individual segments #3 Use formers to shape the segments
Is that correct?

 

[willsonman]

Basically, yeah. So you've already gone most of the way. Your post #6 already has the fuselage segmented already so you just need templates for the fore/aft of each section and then cut the main outside stuff. After that, then worry about the inside stuff. You can even assemble a top/bottom or port/starboard halves and hollow out each half with a rasping file, Dremel tool, or even a hot wire loop. You can make it as complicated or simple as you want but that is the basics. The hot wire wing is pretty standard stuff. The tips will need to be hand-shaped obviously but you're not even dealing with an elliptical wing. Segment it off and scale your airfoil according to chord length.

 

[cudi]

Basically, yeah. So you've already gone most of the way. Your post #6 already has the fuselage segmented already [...]

Not quite,the blender project was designed for former/covering method. The one I have now (made using hot wire) lacks the wing root What was done: using the styrofoam thickness as segment lenght (e.g. segment according to plans is 9cm, so I use 5+2+2 cm board), use the flat part of the board as a starting place I fix half of the former (same on the other side and cut). Results are ok however I lack the wing root as mentioned

 

[cudi]

This is the source of this method However, as in most cases, the build shows nicely how the dude cuts out the segments and then suddenly poof! there are wings present I really would like to see how someone takes those measurements and cuts out that space for wing installation Because I don't know why, but people seem to skip this part all the time in all tutorials

 

[cudi]

OK, getting close using templates from plans... Not perfect though, seems about -1 /-2 deg to port side. I think it will be sandable later on.
Some progess photos:

There is a small part on the belly to be glued after the center of the wing is fixed in it's position.

Starts to look familiar

 

[cyclone3350]

This is the source of this method However, as in most cases, the build shows nicely how the dude cuts out the segments and then suddenly poof! there are wings present I really would like to see how someone takes those measurements and cuts out that space for wing installation Because I don't know why, but people seem to skip this part all the time in all tutorials

Thanks for the vid. I drew up plans for a sport jet based on this this type of construction. I wasn't sure if this method would work out when I was thinking about doing it this way. Now I am starting to feel a bit more motivated. Your project is shaping out very well. I set up a thread if U would to contribute any pointers on foam cutting here. https://forum.flitetest.com/index.p...m-cutters-please-feel-free-to-weigh-in.69325/ @Taildragger is also working on a project using this method & I am sure there will be more from other folks out there. Looking good & keep posting.

 

[cudi]

Thanks for the vid. I drew up plans for a sport jet based on this this type of construction. I wasn't sure if this method would work out when I was thinking about doing it this way. Now I am starting to feel a bit more motivated. Your project is shaping out very well. I set up a thread if U would to contribute any pointers on foam cutting here. https://forum.flitetest.com/index.p...m-cutters-please-feel-free-to-weigh-in.69325/ @Taildragger is also working on a project using this method & I am sure there will be more from other folks out there. Looking good & keep posting.

Will take me some time to through those 7 pages But already I can see that I can use some stuff out there The thing that caught my attention was that everybody seems to be using a nichrome wire.... I'll have to try out it when I'll have the chance, as SS is enough for now

 

[cudi]

Time for the most delicate part - the tail cone:

 

[FlyerInStyle]

Time for the most delicate part - the tail cone:
View attachment 223169
View attachment 223170

Wow! That is just amazing!