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1/4 Scale Charlesworth ASK13

Let us all watch your new project progress.
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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: 1/4 Scale Charlesworth ASK13

Post by Peter Balcombe » 10 Oct 2019, 11:15

So...., with a set of laser cut parts as shown below, let the build of the 2nd wing commence.
The first job was to cut & splice the tapered spars as for the first wing, but this time the rear spar web can be assembled & glued to the spar ready to accept the ribs.

Then it is a simple matter to slot the ribs onto the spar/rear web over the plan, the lower building tabs giving the washout angle along the length of the wing. The False LE is also added to correctly align each rib as you go.
(I initially used a couple of 1/4" blocks to support the lower spar at root & mid span until enough ribs were in place to take over the job)
The 2 servo trays are also fitted between the appropriate ribs as these are slotted into place. Thin wing type servos can easily be fitted into the plates from the bottom.

Finally, the root rib is attached to the spar (with the dihedral angle defined by the end of the root web) & the separate root piece of false LE inserted.
Th pic below the initial assembled structure with the top spar sat in place to check fit.
Attachments
2nd wing parts.jpg
Laser cut parts
2nd Wing structure.jpg
Wing structure

Greg Smith
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Joined: 26 Jan 2016, 00:20

Re: 1/4 Scale Charlesworth ASK13

Post by Greg Smith » 11 Oct 2019, 19:02

I am amazed at your productivity, Peter: congratulations! I am still off and on with the second wing of the Olympia, but events here in the US are consuming an addictive attention, to say nothing of events there, too. Best, Greg.

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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: 1/4 Scale Charlesworth ASK13

Post by Peter Balcombe » 11 Oct 2019, 20:02

Many thanks Greg.
I have to keep moving as I still have another 3 projects waiting in line :o

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Cliff Evans
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Re: 1/4 Scale Charlesworth ASK13

Post by Cliff Evans » 11 Oct 2019, 23:40

And the rest!!

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Peter Balcombe
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Location: Clevedon, North Somerset, U.K.

Re: 1/4 Scale Charlesworth ASK13

Post by Peter Balcombe » 12 Oct 2019, 11:35

The ply TE strip can be held in place beneath the ribs & quickly attached using cyano.
Then the balsa infill can be glued into place (use of spruce strip underneath to ensure straightness is recommended). I used a 25mm wide strip of 1/16" balsa followed by a further 1/4" wide strip at the front. (the infill is sanded to profile before the top TE ply strip is put on later).
The main joiner tube is epoxied into the rib slots & then blocked in using 1/8" ply as for the first wing before the top spar is added.

Once the top spar is in place, inverting the structure allows the ply front spar webs to be put on (I needed to run a thin file down the rib slots to slightly enlarge them as the main spar had encroached a little).
Then, the webs pieces can be carefully slid into place. I applied cyano to attach the web faces to the spars once they were fully in place, but slower acting glue could be applied before final insertion once you are sure that they are going to slide fully into place.

With the rear incidence tube slid into place through the laser cut holes, this can be epoxied at each rib. (I double checked that the rear tube was parallel to, & at same angle as the main joiner by temporarily inserting blade/rod).
Once the rear incidence tube is fixed, it can be blocked into each rib & other lower sub-spars fitted.

The pics below show the progress and also show the aileron servo cable, & root rib servo connector, access holes as manually added on the first wing.
Attachments
LHWing TE on.jpg
LH Wing Rear tube block.jpg
LH wing Front root web.jpg
LH Wing outer web.jpg

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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: 1/4 Scale Charlesworth ASK13

Post by Peter Balcombe » 16 Oct 2019, 12:50

With the 2nd wing quickly built to about the same stage as the first, I decided to get to grips with the wing root TE fairing.
The drawing has note which says that a 2.4mm balsa sheet fillet is inserted between the 0.4mm ply TE strips, but then talks about tapering from 4.5mm to zero over the span of the fillet! The shaped fairing is then skinned with 0.4mm ply.
Looking at a photo of the full size, what I think the drawing note means, is to insert a fillet core between the 0.4mm strips, then 4.8mm balsa is put each side to block out roughly to the the root rib thickness, tapering the blocks to nothing over their span.

I have decided to use a 0.8mm ply core to give a better defined edge, with 1/4" balsa blocks as shown in the pics prior to shaping.
Attachments
K13 Root TE fairing pic.jpg
ASK13 Root TE fairing
K13 Root TE core.jpg
Root TE core
K13 Root TE fairing1.jpg
K13 Root TE fairing2.jpg

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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: 1/4 Scale Charlesworth ASK13

Post by Peter Balcombe » 17 Oct 2019, 14:35

Now that the 1st wing root TE has been strengthened, the outstanding job of making holes in the root end ribs for the rear incidence tube can go ahead, using the other wing to ensure good alignment (2nd wing had laser cut holes for the tube).
Finally, the part built wings can be put together.
Attachments
Wings joined1.jpg
Wings Joined2.jpg

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RobbieB
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Re: 1/4 Scale Charlesworth ASK13

Post by RobbieB » 17 Oct 2019, 17:14

Started a K13 - ended up a Horten!

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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: 1/4 Scale Charlesworth ASK13

Post by Peter Balcombe » 20 Oct 2019, 14:23

Don't worry Robbie. The wings will soon be attached to a fuselage :)

Meanwhile, the airbrake slots have been released in the wing ready to accept the brake boxes & the brake components prepared.
(The blades & box sides come as laser cut items)
In order to ensure all parts have the same centres, the brake arms are assembled as a set, checking that the three pivot centrelines match up.
Attachments
Brake slot.jpg
Wing brake slot
Brake parts.jpg
Brake Assy.jpg

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