Trident airliner scratch build
02-24-2021, 07:57 AM
#27
Thread Starter
Now the tricky bit.
I have never done a planked fuselage before. But how else can I make the rear fuselage? And keep it accurate.
So I assembled the parts shown earlier, with a few others, over the side view of the fuselage with integral fin and engine intake.
The bones of the right hand half of the rear fuselage.
I started at the 1/4" x 1/8" balsa longeron and added tapered strips of 1/16" balsa, adding two at a time (one above and one below) using aliphatic glue as it's supposed to sand easier than cyano.
I held all the parts in place while the glue dried with many pins and lots of little clamps.
Trouble is, it takes a while to set. So it took a while.
After some trial and error (my first time planking remember) I got the hang of it. I cut a couple of strips of 1/16" balsa that tapered from 1" to 1/4". Then I cut a wedge off the 1" end down to 3/4" and then sanded the cut edge to a nice curve, leaving the other edge straight. After wetting each strip I glued it in place with aliphatic and pinned and clamped it in place, then same for the one on the other side of the centre longeron.
When it came to the fin, I made up balsa skins and glassed the inside face of them before epoxying one in place. I wanted the fin nice and rigid as it supports the tail. The fin is quite broad.
I had to plank the engine in take bit too, and blend it into both the fuselage and the fin.
Finally, I finished the planking and it looked good. I lifted it from the building board, added the formers and longeron for the left side, and planked that too. When finished planking (thank goodness) I gave it a rough sanding down, a bit of filler and a final sanding down, prior to glassing it.
The left side, showing the cut line where the engine access panel will be separated.
The right side, with a slot for the servo arm. The servo mount was added to the inside of a cut-out in the fin skin.
I added a bit of extra plywood to keep the circular shape of the join former.
The inside.
I have never done a planked fuselage before. But how else can I make the rear fuselage? And keep it accurate.
So I assembled the parts shown earlier, with a few others, over the side view of the fuselage with integral fin and engine intake.
The bones of the right hand half of the rear fuselage.
I started at the 1/4" x 1/8" balsa longeron and added tapered strips of 1/16" balsa, adding two at a time (one above and one below) using aliphatic glue as it's supposed to sand easier than cyano.
I held all the parts in place while the glue dried with many pins and lots of little clamps.
Trouble is, it takes a while to set. So it took a while.
After some trial and error (my first time planking remember) I got the hang of it. I cut a couple of strips of 1/16" balsa that tapered from 1" to 1/4". Then I cut a wedge off the 1" end down to 3/4" and then sanded the cut edge to a nice curve, leaving the other edge straight. After wetting each strip I glued it in place with aliphatic and pinned and clamped it in place, then same for the one on the other side of the centre longeron.
When it came to the fin, I made up balsa skins and glassed the inside face of them before epoxying one in place. I wanted the fin nice and rigid as it supports the tail. The fin is quite broad.
I had to plank the engine in take bit too, and blend it into both the fuselage and the fin.
Finally, I finished the planking and it looked good. I lifted it from the building board, added the formers and longeron for the left side, and planked that too. When finished planking (thank goodness) I gave it a rough sanding down, a bit of filler and a final sanding down, prior to glassing it.
The left side, showing the cut line where the engine access panel will be separated.
The right side, with a slot for the servo arm. The servo mount was added to the inside of a cut-out in the fin skin.
I added a bit of extra plywood to keep the circular shape of the join former.
The inside.
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Viper1GJ (02-24-2021)
02-24-2021, 12:27 PM
#29
Thread Starter
Thank you Viper, but it's a pretty rough bodge-up job when seen up close.
Back on the drawing board (screen), I'm trying to work out where everything inside goes, and how to get it there and hold it in place, with limited access.
My original plan was to glue the fuselage rear onto the middle bit, but access would be nice.
So I could make it removable, or put everything in from the front.
Back on the drawing board (screen), I'm trying to work out where everything inside goes, and how to get it there and hold it in place, with limited access.
My original plan was to glue the fuselage rear onto the middle bit, but access would be nice.
So I could make it removable, or put everything in from the front.
Yesterday, 11:37 AM
#30
Thread Starter
Some of the add-on bits of the aircraft caused a bit of head-scratching. I needed a pair of light dummy engine nacelles, preferably hollow to reduce drag, a fairing around the tailplane on the top of the fin, and a sort of rounded lump where the APU is mounted below the rudder. Balsa planking was not an attractive option, so what could I do with a hot wire on foam?
I cut two semi-cylinders out of blue foam, the closed cell type used for floor insulation. One was 2.5" diameter, the other 1.5". I glued two of these together to make a cylinder.
In the larger ones I cut a groove before joining the halves, then I cut lengths of the cylinder to the size of an engine nacelle.
I cut narrow circles from 1/8 birchply for the intake and exit holes and epoxied them on the ends
I used my belt-sander to shape the foam to the form of an engine cowling, finished them off with a sanding block, a bit of filler to correct errors, more fine sanding to get a smooth surface.
Two halves make a whole (cylinder).
Having a spare sometimes avoids having to scrap one and start again.
Then I glassed the outside with 25 gram (1 oz) glasscloth. When that was cured and trimmed, I fed the wire of my single handed hot wire cutter along the slot, reconnected it, and used it to hollow out the inside.
Glassed, then hollowed.
They're hung on the back so need to be light.
The smaller blue-foam cylinder was tapered at both ends, smoothed and glassed to be the fin-top bullet. An offcut was shaped to represent the APU housing, and more blue foam was made into a rudder.
The finished bullet fairing for the tail/rudder join, and the rudder (not yet glassed).
I cut two semi-cylinders out of blue foam, the closed cell type used for floor insulation. One was 2.5" diameter, the other 1.5". I glued two of these together to make a cylinder.
In the larger ones I cut a groove before joining the halves, then I cut lengths of the cylinder to the size of an engine nacelle.
I cut narrow circles from 1/8 birchply for the intake and exit holes and epoxied them on the ends
I used my belt-sander to shape the foam to the form of an engine cowling, finished them off with a sanding block, a bit of filler to correct errors, more fine sanding to get a smooth surface.
Two halves make a whole (cylinder).
Having a spare sometimes avoids having to scrap one and start again.
Then I glassed the outside with 25 gram (1 oz) glasscloth. When that was cured and trimmed, I fed the wire of my single handed hot wire cutter along the slot, reconnected it, and used it to hollow out the inside.
Glassed, then hollowed.
They're hung on the back so need to be light.
The smaller blue-foam cylinder was tapered at both ends, smoothed and glassed to be the fin-top bullet. An offcut was shaped to represent the APU housing, and more blue foam was made into a rudder.
The finished bullet fairing for the tail/rudder join, and the rudder (not yet glassed).
