Building Aero 3D Day 4: Joint, Trials & Former Gluing

Scarf Joint

Wednesday Peter came over after we both had some time to contemplate what we were missing the session before. Due to my lack of experience I would have been hard pressed to come up with the correct answer; however, Peter determined what the diagram was trying to tell us and that was…… *drum roll please*…. a scarf joint!

As you can see in the featured image above the length of the balsa stringers needed to be extended/strenghtened via a scarf joint. The way this work is you want the joint to be 8 to 10 times the length of the thickness. In this particular case we are using 14” balsa and Peter made the joint length 12 times the thickness. Which is 12x14“=3”. This is cut at an angle from the top at the measurement to the bottom at the end of the balsa stringer (repeated for the piece that is going to fit on top).

We re-pinned everything down and in the next session, hoping, we will actually glue what we trial fitted last time into place. This session, however, we did some more sanding to make sure all the pieces were ready.

To ensure the balsa stringers are flush with the outer edge of the doubler we measured and cut a 14” x 18” piece out of the bottom corner of former four so half the stringer width fits underneath.

Lastly I glued formers 3 and 4 together using 30 minute epoxy and clamped it into position, as seen in the image below.

Formers 3 & 4 Glued Together
Formers 3 & 4 Glued Together

Next time will hopefully be getting the formers and doublers glued into place on the stringers.

Building Aero 3D Day 3: Fuselage Contemplation & FUDA’s

Fuselage Conundrum

Yesterday Peter came over to assist with getting the fuselage situated. He brought a china marker (white) to make a straight line on the table, providing a center point for the fuselage. I marked the center on the bottom of each former so that we could ensure the fuselage is center properly.

The very tail piece was center and pinned into place at the far right (matching the diagram instructions) and two 14” x 14” balsa stringers were pinned in place. Based on the diagram I figured the spacing would be determiend by this step as they do not state how far each former needs to be from the next. When we placed all the pieces together as shown in Step 3, FU 2-10, and campled them into place (no gluing, this is purely a dry run) we determined that this was not the case and to top it off couldn’t figure out how the stringers were to fit into the slot of the front side pieces (FUA’s) as from what we could tell the outer edge should be smooth; however, the stringers definidfely protruded at the front… even though we never cut it down to size, this wouldn’t have mattered for this case. We did, however, move the ‘front assembly’ back and forth along the stringers to see if we could make sense of the situation. The side panels of the aircraft are to be 51 inches long so we were trying to get all the numbers to work out based on the lenth of the tail wheel plate at the back of the fuselage, the stringers (FU-ST-1 – which are suppose to be 37716” in length), and FUA’s (believe these to be the doublers for added support to the engine block, etc. at the nose of the aircraft). We seemed to be 2″ short and didn’t think this was accounted for by the forming/fitting of the side panel to the formers.

These steps are critical and need to make sure everything is positioned correctly along the stringers and at right angles; because if it is off at the back it will only get worse as you move towards the front, each step along the way exacerbating the situation (that is potential twisting/warping of the fuselage). You can see how we left things in the image at the top. We decided to pause and let things perculate for a while. If you are not sure then don’t proceed. Will likely get some additional input from other modellers before moving forward… stay tunned.

What I did get done this day, besides contemplation and discussions around the fuselage, is gluing what appears will make up the landing gear block (FUD & 2 FUDA’s stacked on top) glued together by mixing up some 30 minute expoxy. You can see them clamped together drying below:

FUD & FUDAs Glued
FUD & FUDAs Glued (Make up landing gear block?)

In conclusion, though this day was not as fruitful as we were hoping, troubleshooting/problem solving and discussing with our fellow aeromodellers is part of what this hobby is all about!

With luck, I’ll be able to make more progress later this week.

Building Aero 3D Day 2: Formers and Balsa Gluing

FUD and 2 FUDA's Sanded

Today I made some more progress on the fuselage of the aircraft. I started by cutting, from 1/4″ x 1/4″ balsa stringer, two pieces for cross braces in former 7 which was 2116” and in former 8 which was 1516“. Once cut I used medium CA, placed on the ends of the balsa and top and bottom where it wil be making contact with the former.

I inserted the balsa piece into the former and pinned in place (the pins kinda seemed uncessay as medium CA dries very quickly). I did this over wax paper to minimize my chances of getting glue onto the pinning surface of the workbench. The result is seen in the bottom left picture.

Next I cut out formers 3 and 4 out of the 18” ply and sanded the exterior perimeter, except the curved (bottom) portion of FU3 as nothing will be gluing here. The idea behind sanding (to my knowledge) is to remove the laser burn and create a surface for the glue to more easily stick… also removes the rough jut outs from where I cut the tabs holding the pieces into the main ply sheets.

Lastly I cut out the two FUDA’s and removed the plastic wrap around a bundle of pieces to get FUD. The two FUDA’s are going to get glued together and then glued to FUD. Looking ahead in the instructions these pieces when inserted into the bottom of the fuselage between formers 2 & 3 are going to make up the mounting point for the landing gear, as the wires will be recessed inside… stay tuned for when I get there (Step 10)! You can see them sanded in the featured image both along the external perimeter as well on the internal perimater for the FUDA’s.

That concludes another building session… stay tuned as I plan to get steps 1 and 2 fully completed soon!

Building Aero 3D Day 1: Sanding at the Rear

Aero 3D Fuselage Plan

Winter is upon us again… that means it is back to building season! This build is going to take on a bit of a different dynamic as a big thank-you goes out to Peter & John for helping me build a workbench in our mudroom. I’m excited to be able to go at my own pace from home and see how well I do as it’ll be less structrued and me troubleshooting alone along the way… that said the guys are not far away if I require assistance!

Speaking of, on Nov. 17th Peter came over and graciously leant me some tools to get me started. We looked through the kit, explorered the manual, came up with a game plan as to how to approach this build and interpret the diagram based building instructions. Mr. Aerodesign approaches things differently. More thoughts on this in a future post once I have more experience.

The aircraft I’m building is an Aero 3D, which should allow me to get into 3D flight (also good for smooth flying) as the thick airfoil and oversized control surfaces give this aircraft exceptional flight caracteristics, supposedly and what I’m hoping to find out! 🙂

Throughout my posts I am going to describe the pieces as I think they are with the labels Mr. Aerodesign provides in the manual, i.e Former 7 (FU7).

While Peter was there I cut out a half dozen pieces from the two 1/8″ ply sheets to start the rear of the fuselage. Specifically formers 7-10 (FU7-10)

On Nov. 18th I gave all the aforementioned pieces a light sanding to remove the ‘laser burn’, which helps the glue stick. Need to make sure you don’t oversand; otherwise, where the 1/4″x1/4″ balsa stringers fit into, or other parts go together, will be to loose.

I skipped step 1 as it requires some gluing, but will prep those pieces and do some gluing once my supplies arrive!