Still relatively new to rc scratchbuillding but have made and successfully flown a few planes, problem is i need to aquire some knowledge in making a box type fuse - all my other builds have been profile types. I use 10mm epp as i have a heap of it but my last 2 attempts have been bad - they twist easily and sometimes hard to keep everything square and true. I am not too keen on making just a square tube, i like to draw up ideas that have nice curves and access to electronics easy, so there is another part i struggle with - the access hatches.
Is there any type of tutorial on all the fundamentals of building a fuse, eg i dont even know what formers and doublers are I realise i could just build other guys planes and follow instructions but was hoping for a bit of a knowledge so i could put my own creations together.
I apologise if it seems like i am trying to take the easy road but any helpful links would be appreciated.
Cheers,
Mick.

Two threads with looking at and they are build logs but I think with help are the wot-next - realy simple box build and the Infineon bipe. The Infineon is more complicated and would require plans but is EPP so it'll give some idea of strength requirements.

Formers are supports that run perpendicular to the fuselage. (Like bulkheads on a boat.)The are usually 'hollow' like a ring but can be solid or anywhere in-between. Here are some for a full-sized plane.


Here you see them between the two sides of a model fuse.


The can attach directly to the fuselage 'skin', or to stringers, which are strips of reinforcement that run the long way down the fuselage. I don't often see these used in foam builds.

Doublers - I think - are just places where you've doubled the thickness of the fuselage (i.e. glued another piece of foam to it to make it thicker.)

As I'm not a great builder, something I've done on a couple of builds is a sort of compromise between a profile / square tube / full fuselage. I cut the fuselage so that it has the correct shape when seen from the top, the sides, or the bottom but, in cross section, it's still basically a box. It's easy to build, really strong, and has a nice taper from nose to tail, etc.

This Tiger Moth is built that way:


As is my Sporty Little Plane:


This shot of my Moth under construction gives a better idea of what I'm on about.

Thanks chittyfather - i have been watching the wot next, might end up using those techniques, just worried a bit about flexing with the epp, i will look further into the infineon.

Mclarckson - i am interested in the way you made your fuse, any build guides to it at all?

I built the Blu-baby 33" monoblockless, original design by Tony65x55 and the monoblockless kit was redesigned by dz1sfb (Ken). The thread with plans and very well-done and detailed build photos/guide is at http://www.rcgroups.com/forums/showthread.php?t=1577227. If you take a look at the plans or even better, try building one, you'll see how Ken designed the box fuse. It has doublers for strength, and the pieces are designed with tabs and slots so that they fit together plug-in style. It's nearly impossible with that technique to get the fuse out-of-square if you ask me. Looking at the plans will definitely help but having foam pieces, cut, in your hands, and gluing them up will give you a much more in-depth knowledge of how it works.

For an example of formers and a very complicated build that turned out absolutely incredible then check out Jurgen Be's Stinson Reliant SR10 build. The thread is at http://www.rcgroups.com/forums/showthread.php?t=1205233. His build pictures are detailed enough to show you how it's constructed and the end result is simply stunning.

Hope this helps some
Ben

Start by making a simple rectangular Box fuselage .. after that move on to more complex shapes , by adding , or subtracting to the Box...

Great minds...
I was just going to comment that gpw had a thread on the universal fuse back in the archives that I found useful a couple years ago.

I did a BB in epe (Polyethylene foam) and found when flying last winter that the EPE shrunk so much in the cold that the fuse shortened and the wire ele control rod pushed the ele to up, and I could hardly fly it. I'd take it outside, throw it up, and fly ok for a couple minutes and then had to keep pushing ele down, down, down to fly straight and level. So, you might have to consider that thermal expansion/contraction issue. (although in Queensland, you might not get that much temp change....)

UF.. that was a good one eh ? So long ago ... now I’d want one Bigger....hahahaha

Originally Posted by gpw

Start by making a simple rectangular Box fuselage .. after that move on to more complex shapes , by adding , or subtracting to the Box...

+1
That's exactly the way I went with my most recent build. I used the concepts but not the shapes from the David's wot-next and then added in one curved area up front. The Infineon is skinned with 3mm EPP and goes together in a really stiff fuse, so don't rule it out as a concept.
Nice curved tubular fuses are infinitely possible but by starting boxy you'll get your head around the interal structures you're going to need for fixing tail feathers and wings, compartments for electrics combined with fire walls/bulk heads need for strength in given areas.
I'm working on a build log for my newest bird that will show some of the things you've mentioned including hatches and it'll go in this thread if you want to take a peek. http://www.rcgroups.com/forums/showthread.php?t=1738983

Graeme

Originally Posted by micka80ella

Mclarckson - i am interested in the way you made your fuse, any build guides to it at all?

Definitely check out the Blu-Baby thread as recommended above as it's better documented than my builds and I use basically the same technique. Important note: If you decide to build one (and you should) ignore the plans' 1" width. Make the plane at least 2" wide unless you have very long, very thin fingers. You've been warned.

Here's the build of my Tiger Moth. On that one, I made the monoblock into a fun 3D puzzle of sorts, since I had to put it together out of lots of 1/4" foam.

Here's the build of my Sporty Little Plane. This one also uses a heavily chopped up monoblock. In this case, I didn't plan it out but modded it as I went, and waited until the end of the build to glue it in place. By that time, I'd gotten a better handle on where to put the battery etc. to balance the plane.

Thanks for all the help, do you guys mind if i post a pic and give advice as to what needs doing?

go for it, that's what it's all about!

Ok, this fuse still doesn't have the top glued on, but i need to minimise the twisting. I built one like this before and it had a twisting problem. The skewers are not glued in, i was trying different bracing methods, the bottom has two cf square tubes glued on. I was hoping for lots of access to the inside. What do you think - the skewers feel like they might work but looking for suggestions that are more standard procedure.
Cheers,
Mick.

What kind of twisting are you getting? In which direction?

You're using EPP, is that correct?