Now I do not build model aircraft like most. Even if I am going to build from a kit or even this short kit, many changes will be made. First off, When I build the fuselage, it will only be used as a plug for making the final fuselage out of fiberglass. Second, if I am building from a kit, I am generally making a different version of the aircraft than they have kitted and this requires many modifications.
Tremendous advantages to making the fuselage out of fiberglass: 1. The fuselage will weigh about 1/3 of the wood one. 2. It is hollow instead of having a bunch of formers, blocks of wood, plastic hatches, etc. etc. 3. It is so much stronger than the wood one that it is beyond description. 4. sitting in the corner of your shop is this plug after you have built the aircraft. if you crash, you have the plug for making another one. Friend want one, no problem.
I lay my glass fuselage right off the wood one. No reason to make molds unless you are planning to make a whole lot of them. Molds take a lot of time and expense to make. You do have to use Isophthalic resin because of it's laminating properties. But I love it, It is a tooling resin, very thin and very ridged.
First thing I do here is assemble the jig that aligns all the formers. I then take a bunch of formers that are very thin in some areas and glue in the scrap ply that fits there. Being I am only using this built up fuselage as a plug, I do not need to leave these areas vacant and it makes the formers hold there shape better in these thin areas.
There are 32 of these 1/8 ply formers and half of them are to be doubled up to make 1/4" formers. I do not need to do that either. I just have to add a little piece of scrap ply to them where the fit the slots in the jig.
All the formers from the intakes back have a piece of ply added to them so they will all slide onto 1/4" dowels for line up.
Now the idea here is to place all these formers on this jig and start sheeting. I will tell you a secret: like almost all of these laser cutting company's, they have cut their stuff from plans provided by some modeler and almost always, they have never even tried to build the model. They do not have a clue how accurate, or not, this stuff goes together.
Right off, former #30 has the holes for the dowels spaced 3/8" to wide and will not slide on the dowels. I have to figure out what is wrong here. Is the former too wide or are the holes wrong? The former is wrong and I have to take 3/8" out of the center of it.
OK fine. I now have the formers on the jig. The next step is to start adding braces to the formers that are twisted or warped. Then start adding braces to the assembly to get everything aligned. If you look at this photo attached here you can see everything that has to be done before ever starting to sheet.
The most important step to sheeting a bunch of formers like this is to cut yourself a piece of 1/8" x 36" x 1/4" wide piece of balsa. This is your testing strip to lay across the formers in all the different areas to check their placement. Do all the formers line up correctly and make contact with this stick. If a former is drastically out, why?
One former is 1/4" too high. Another is right on the bottom of the fuselage, but 3/32" too low on the top. Any where I place this stick, there are formers that will have to be shimmed on way or another to make this fuselage without serious waves in it.
OK let's get to the truth of the matter here. Does this make this short kit a bad investment? The truth is: NO. I do not care if you cut your own formers for any aircraft you are making yourself, even computing them yourself, you will run into this. It is to be expected with this type of construction. The trick is to check the alignment of all formers as you build it with some kind of strip spanning over the formers.
I checked with "Jim" at Hobby Barn who this short kit is made for. These inaccuracies are known to him. Other modelers have run into the same thing.
Now what is sad here to me is I actually went to the effort to re-draw some of these formers and sent a very carefully worded E-mail to this laser cutter showing him the corrections he could make by simply correcting his computer that does the laser cutting. I told him I would be willing to continue to send corrections if he wanted me too. Never heard from him.
Between the tremendous amount of time I spent getting all my formers right and the sheeting of this large aircraft, it took me 472 hours to build it. (yes I keep track of my time and expense)
To be continued . . . .