abufletcher

Here's the first stage of the rear fuselage assemble. The bottom consists of three pieces of 0.4 ply and two short lengths of C-beam. You glue these down together, then put the 6mm balsa stock and 6mm balsa "gussets" to turn it all into one piece. Then, you position the formers at an angle using the liteply templates provided. I just beveled the bottom of the balsa former frames by hand.

abufletcher

Since I didn't make a trip to the US during Xmas and won't be going in March, I'm running low on supplies, for example, CA. [] I guess I need to place another order and pay the 30% extra to get it here. [:@]

abufletcher

This kit's extremely innovative method of fuselage construction can seem a little odd at first but it really does virtually eliminate the possibility of an asymmetrical or twisted fuselage. And this is all the more amazing considering that no part of the fuselage is built over the plan! The front end could just as well be assembled on your kitchen table or the desk at work ( ) and the rear half only needs a flat surface for the first few steps. After that, the bottom rear section "docks" with precision with the UC cross-beam (itself locked in position) and the formers of the front half to ensure perfect alignment. The only challenge on the prototype was finding the exact placement of the rear formers, but that will also be made fool-proof (i.e. "Don-proof") in future kits.

I think what comes next is to add the top longerons. [sm=50_50.gif]

abufletcher

The bottom rear section has now been "docked" (with epoxy) onto the forward fuse underside. The fit is very precise so there really isn't any way to mess this up. But, of course, somehow I managed to anyway...well just slightly. As always, you measure and measure and measure and test-fit again and again, but somehow when the glue has dried, something always ends up a hair out of place. [sm=rolleyes.gif] But no problem.

I did make one minor modification. I noticed that the ply bottom was unsupported just behind the UC C-beam so I added a length of 4x4mm hardwood to the leading edge of the ply sheet. I suppose balsa would have worked just as well. Then I cut two notches in keel pieces to accept this support piece. The bottom ply should be flush with the C-beam. And it was, but somehow after the glue had dried (of course) I noticed the middle sticks up just slightly. Anyway, I can live with it. And I can sand it down if need be (since there's the hardwood support piece beneath it. But since I plan to use a natural finish, I'd prefer not to cut into the ply revealing the layers. It's one of those things no one else would notice, but the builder knows it's there.

The next step in the innovative construction involves propping up the rear section relative to a level forward section. This is what the "feet" on the forward fuse (beneath the engine compartment) are for. These hold the forward section level. Then, with some weight on the center section, the rear can be propped up and then the top longerons added to lock in this angle. This is basically the same as the way modelers prop up a wing to add dihedral.

Again, it's all perfectly flat and straight and just about fool-proof. So let's see what I can manage to mess up this time!

eagledancer

abu, do like i did, i bought 1 and 4 lbs bottles of ca from fleabay, keep it in the freezer and refill my small hobby shop bottles as i need it

abufletcher

The top longerons are now in place and it's starting to look like a real fuselage! I taped the bottom to a piece of wood to ensure that the bottom was perfectly flat (as is on the plans). And then propped it up to the correct height. As I was gluing each of the rear formers I rechecked the angle of the uprights with the template. As you can see from the front view, this results is a very straight fuselage.

abufletcher

Ah. Apparently, I need to add the skins before I take it down off the blocks. It's the skins that act as the bracing, which holds everything in position (as on the original).

So it looks like assembling the skins is the next task.

abufletcher

Actually, a lot of things need to be "just perfect" before I proceed, so I need to put on my thinking cap.

abufletcher

Back to the glass building board! I positioned the fuse over the bottom view and tack glued the "feet" and the ends of the UC C-beam to the glass. Then I made a wedge (using the angle on the side view) and slipped that into position until the tail was (again) at the right height. Then I tack glued the wedge onto the glass and added a couple drops on the fuse bottom at the position of the skid C-beams. So now the fuse is firmly anchored to the glass and ready to be skinned.

ACTUALLY, it's NOT quite ready to skin. I still need to add several parts to the rear and also add the longeron sections on the front (which would have been easier to do BEFORE I glued the model to the glass [:@] ). Oh, well.

fliegertom

Hello Abu.
Now i'm here and i've got an account too My English is awfull, but i hope you all will understand my comments. It would't be very much :-)
Abu, ich weiß, tief im Herzen verstehst du mich immer ;-) And i hope, the other users will do the same.

Abu, well done! Yes, we can!!!

semeraro

Hi Abu,

Oh, you glue the parts to a glass building board. My pins keep bending. Actually, I have seen several modelers using glass building boards. I have always wondered how you use them. How thick is the glass? Must it be on top of a perfectly flat surface? What kind of glue do you use to stick parts to it? How easy is it to get parts to come off? My work seems to always have a small degree of warp in it no matter what I do. Maybe glass is the way. Nice work so far by the way. This albi is one of my favorites.

Dave

geezeraviation

My Feedback: (3)

Dave, I've built on glass for twenty years and use little 1 lb lead ingots to hold parts down, I call them my "pins". Have glued parts down when they're small or hard to hold, single edge blade to pop them off. Use very little glue.
Doc

Mein Duff

FliegerTom, Herzliche Wilkommen zu diese interresant project...Es gibt einige von uns die Deutsch einigermasse vertsehe so deine English ist auch kein problem fur uns, Es ist sowieso eine Deutsche Machine die hier gebaut wird!
Hier ist ein wunderbar gelegenheit zu sehen wie eine Prototype und seiner begleitende Probleme gelost wird....
Mein Duff

abufletcher

I have an idea! Why don't you just finish up for me here and I'll finish up for you over on RC-network! I can call myself "Flieger-Don" and you can be "abu-thomas." Anyway, welcome to RCU and don't hesitate to post photos of your CI.

abufletcher

This is the first time I've built on glass, but Chris convinced me it was the best way to go with this model. It's a bit odd since the wings are actually built ABOVE the glass but with the ribs at the correct angle. This method allows us to build in scale washout throughout the span of the wing. It took a bit of learning at first to get the parts lines up with the plans (because of the visual separation, just use a small triangle) but now I'm glad that I've added this technique to my building skills.

As far as the glass surface itself, the sheet is about 1/4" thick and I place this on my usual building table. So I guess it's no flatter that otherwise. I use thick CA to spot glue the parts. Since I'm really building above the plans and above the glass, I'm not really gluing the parts themselves to the glass. On the wings, the only thing that gets glued to the glass are removable tabs and the spar jacks. These are easily cut off later and "cleaning" the glass is a simple matter of scraping is down with a single-edged razor. In principle, you COULD build this CI on a traditional building board with pins, but it's a lot easier and more secure doing it this way.

abufletcher

Naja, Tom ist mit seiner Prototyp schon viel weitergekommen als ich mit meiner! Er wird seine CI wahrsheinlich auch in diesem Sommer fliegen können! [sm=red_smile.gif]

http://www.rc-network.de/forum/showt...168193&page=19

abufletcher

While I'm considering how to proceed, I finished up a few small things. First I added the remaining 6x6mm balsa longeron sections up front. Then, I inserted the hardwood sections in the tail that will support the stab braces. It's critical to get these last couple of formers in exactly the right locations since it all has to align with the spars for the stabilizer halves. I don't really trust myself to just get it right so I'll probably make the stab and then make sure it all lines up with that.

I also test fitted the ply skins. I'm still thinking of the best way to add the skins. Chris has originally envisioned first assembling all the skin section into full side skins and then putting the whole thing on at one time. The alternate approach would be to add them one at a time starting in the rear so that forward panels always overlap the rear ones. Each panel edge needs to be carefully chamfered (on the inside) for a smooth, scale effect.

abufletcher

Soliciting advice: How would YOU glue the skins to the frame? In particular, what glue would you use and how would you keep from messing up both the inside and the outside, since I want to have a nice stained/varnished surface (inside and out)?

Tom used an interesting method on his CI. He coated the parts with white glue and then let them dry. He then positioned the parts and apply a heating iron to the outside which melted the glue.

I've also got contact cement.

abufletcher

You know I'm very tempted just to take the easy way out, and use one of the grey "color" schemes. It would all be SOOOO simple.

Mein Duff

Now don't take the easy way out ...ever... that would not be in the spirit of our mission.
I would try using white wood glue (sparingly) and then wiping up the excess quickly with wet Q-Tips or what ever allows to get into the corners..
I can also imagine using 1 hr expoxy and cleaning up corners again with lacquer thinner....again, epoxy sparingly applied..
how about taping off the larger areas with tape first if you can get your fingers in there?
Let us see how it works out

allanflowers

I used contact cement on my Siemens Schuckert and it worked very well. I didn't have a single place where the stain was non-uniform because of glue spots.
It is a good idea to use pins to position the panel, just off the surface, then push it down into place. I'm sure you have used this method for things like multilayer formers, etc.
In some cases I would use titebond for the center area that would initially contact the fuselage, with contact cement around the edges. This allows a little adjustment at the moment of first contact.
In any case, it is best to preform the panel as much as possible and do a few dry runs for each panel.

abufletcher

Ideally the overlapping skin panels should be chamfered (beveled) like this. Achieving this is practice will be a challenge.

geezeraviation

My Feedback: (3)

Abu, that's referred to as a scarf joint. when they were building Albatrois by the score the formula used was that the joints bevel was up to 10 times as long as the thickness of the material. ie on a 1/8 thick sheet the bevel would be 1 1/4 long. Incredible what! Not practical at our scale.
Doc

abufletcher

I put the fuse aside for the moment (actually just turned the glass around) so that I can complete the stabilizer before finalizing the tail of the fuselage. Chris has used the technique of laminating thin ply to balsa parts to create a light yet scale structure. Having scale structure is important since every spar and rib will be visible from below in flight.

The stab and rudder are also built "up in the air" on removable jacks. I'm not sure I quite understand how this is beneficial here.

The prototype kit provided 6mm carbon fiber rod to use for the stab and rudder leading edges. But following Tom's lead, I've substituted 5.3mm carbon tube. The one meter rod weighs 42.5g while the tube only weighs 19.5g. I'll also be replacing the brass rod/music wire with carbon tube/rod so that will ofter significant weight savings in the tail. To put this in perspective, by making these substitution, we can save almost half of the weight saved by all of the revisions to the forward fuse parts. Or, in yet another way, this 50g or so saved on the tail equals about 200g up front.

**One suggestion though on the plans: It would be preferable to have both halves of the elevator on the plans so that the builder can construct both at the same time. The other half can be placed in the space to the right where the stab ribs are currently shown (those can be moved or eliminated).

CTDavies

I'm trying to convince Abu the make the fuselage sides as large slab side pieces first instead if attaching all the panels individually. The Smithsonian book on the Albatros DV restoration has a nice detail on how the ply scarf joints looked like. This is what they wrote about the fuselage skins:

The difficult bit here is of course getting the panels all lined as they are supposed to be, so that we don't end up with a banana shaped fuse. This is what I've been thinking of: The fuse panel parts over lap by 8mm. To get them all lined up correctly the modeller draws a long straight line on his building board as a datum line. Each panel has a tiny notch cut it to it (hardly visible) which needs to be placed right on the datum line. If the notches are exactly on the line and the overlaps are all 8mm, the fuse panels are all in the right place. Due to the curvature of the fuse sides the fuse slab sides are slightly longer than the side view, which doesn't show true lengths (of course). The advantage is strong joints between each panel and a smooth curvature even where tighter radii (plural of radius?) occure, where I'm afraid individually placed panels might produce kinks here. Building up the panels is started at the rear as, for streamlining, the front panels overlapped the rear. The fuselage parts can be stacked with a stagger of about 12mm and the edges sanded down as shown to get equal chamfers for the scarf joints.