Jilles Smits 1/3 scale SG38

Let us all watch your new project progress.
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Peter Balcombe
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Re: Jilles Smits 1/3 scale SG38

Post by Peter Balcombe » 06 Nov 2018, 08:49

Please note that my build comments to date are not in any way, shape or form, a criticism of the design, especially this one which has so many parts due to the nature of the beast.
I know from my own very limited design experience, how difficult it is to cover every eventuality and even more so, to remember to cover every detail of every part.
Thus the first build is always likely to find a few wrinkles which can be used to remove these for future builds.

The SG38 is a lovely design & the solid nature of the fuselage construction is so different from the normal rounded shapes, especially as nearly everything is visible in the final product.
All credit to Jilles for producing yet another excellent design.

Jilles
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Re: Jilles Smits 1/3 scale SG38

Post by Jilles » 06 Nov 2018, 09:36

Hi all, nothing what was said about the SG38 details is by myself received as criticism. I just felt a need to explain why I am not 100% perfect like anybody else I guess
I have the same little problems with my Nimbus built that is going on now and reported at an other built thread on this forum.
Peter is one of the first that actually comes back to me with problems he found, I appreciate that because not many other do. Enough said get on with the builds.

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Peter Balcombe
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Re: Jilles Smits 1/3 scale SG38

Post by Peter Balcombe » 06 Nov 2018, 16:35

Moving on ...
Construction of both the rudder and tailplane has started.
The rudder commenced by inserting the top & a lower rib (at the correct angle) into the rudder post, then glueing the carbon strip TE core in the rear NC cut notches. Once this had set, it was a simple job to add the remaining angled ribs.
Rudder top rail still to be added.
Once the LE riblets have been added, the LE will be wrap-around skinned with 0.4mm ply.

The tailplane structure is build largely from NC cut parts, so goes together very quickly.
Note that the angled rib ends ideally need to be bevelled to allow the rib pair tabs to fit into the spar slots (i also bevelled the edges of these).
The rear of the tailplane & inset elevators are next.
Attachments
Rudder Construction.jpg
Initial rudder construction
Rudder framework.jpg
Rudder framework
Tailplane framework.jpg
Tailplane core

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Peter Balcombe
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Re: Jilles Smits 1/3 scale SG38

Post by Peter Balcombe » 10 Nov 2018, 13:31

Elevator framework now built and the trailing edges now have their balsa facings epoxied on prior to profiling.
Elevator LE to be added & then profiled.
The rudder framework is also nearly there with the exception of the top rail (since added together with balsa backing of the LE between the ribs).
Attachments
Tail_Elevator.jpg
Tail & elevator progress
Rudder_TE.jpg
Rudder with TE facing

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Peter Balcombe
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Re: Jilles Smits 1/3 scale SG38

Post by Peter Balcombe » 13 Nov 2018, 15:46

Elevator now dry hinged to check fit & movement.
Can fit tailplane LE skins next, but the rest will probably be left until the various rigging/horn fittings have been installed.
Meanwhile, I tried fitting to the rear fuselage/mast sections to see how large it is becoming ;)
Attachments
Tailplane together2.jpg
Tailplane & elevator dry assembled
Tail_fuselage.jpg
Tail on rear fuz
Tail_togther2.jpg
Tail fitted-from front

SteveArchibald
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Re: Jilles Smits 1/3 scale SG38

Post by SteveArchibald » 14 Nov 2018, 20:55

Hi There Peter,

Beautiful work, I really do enjoy building as much as watching them get built, especially from a set of nice drawings.

Steve

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Peter Balcombe
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Re: Jilles Smits 1/3 scale SG38

Post by Peter Balcombe » 14 Nov 2018, 21:24

Many thanks for the compliment Steve.
A bit more done today, so will hopefully post some photo showing the installed rolled ply rudder & elevator leading edges tomorrow.
Peter

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VinceC
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Re: Jilles Smits 1/3 scale SG38

Post by VinceC » 15 Nov 2018, 08:44

Peter & Jilles strike up a good team. Nice work and well done to both parties

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Peter Balcombe
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Re: Jilles Smits 1/3 scale SG38

Post by Peter Balcombe » 15 Nov 2018, 15:09

Thanks Vince.
Here is a photo of the tailplane once the rolled ply Le has been fitted (using the white glue & ironing technique).
The tip rolled ply sections need to be applied as separate pieces as they taper towards the tip at that point, where as the central part can be done in one piece.
Balsa tip blocks complete the process.
Still a lot of 0.4mm ply cap strips to be added.
Attachments
Tailplane_LE.jpg
Tailplane with rolled ply LE

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Peter Balcombe
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Re: Jilles Smits 1/3 scale SG38

Post by Peter Balcombe » 17 Nov 2018, 13:22

The first wing has now been started and is going together very quickly once you have pre-joined the 2 main spar webbing parts (I fitted a 1/32" ply doubler over the rear of the join area) and spliced up some spruce strip for the upper main & rear spars.
Starting with a few ribs at either end of the main webbing, I glued the ribs (R5 outwards) onto the web & initially held them in place using a dry fitted rear spar. (The notched ply web and bottom building tabs ease this process.)
I then glued the upper 1/4" square main & rear spars into place to firmly anchor all the ribs - note that the spars need to be pressed right down as the remaining space above will be filled with balsa later).
The remaining root ribs can be added by fitting them into the above two spars, spacing apart using the separate web pieces - not forgetting to fit the joiner tube hole doublers to R1 & R4, otherwise the rib positions will not work out correctly above the plan ;)
The aileron spar AS1 can also be fitted to the rear of the outer ribs - not forgetting to add the aileron servo plate at the same time.
Note that the aileron spar and the main (MSE) & rear (RSE) extension spars need to be fitted so that the upper surface slopes downwards towards the tip - note that some of the plan sections appear to show some tip parts upside down, but that is because of the direction the section view is made. The check is that R14 should slot in from the top.
The photos also show a couple of the spruce strip cross braces which can be slid into place via slots cut in the ribs. Note that these need to be firmly bonded to the ribs and the spar tops to add torsional stiffness. Web plates are added between top & bottom cross bracing strips later.
Attachments
Wing Structure1.jpg
Initial wing structure
Aileron servo.jpg
Aileron servo plate
Wing root area.jpg
Wing root area
Wing tip.jpg
Wing tip area

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