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Jilles Smits 1/3 scale SG38**

Posted: 07 Oct 2018, 17:36
by Peter Balcombe
Another prototype build from a one of Jilles’ excellent plans.
Lots of drawing rolls have arrived, plus a full set of laser cut parts from Cliff Evans to make up this 1/3 scale primary glider which includes lots of rigging wires and scale pulleys for the control surface operation.
The servos are largely hidden and the Rx is buried within the pilot’s body :o
All parts have been checked against the Bill of Materials & identified on the highly detailed plans.
Just awaiting delivery of a large pile of stock wood before starting the build.

For a Primary glider there are an awful lot of parts :?
Lasercut parts
Lasercut parts

Re: Jilles Smits 1/3 scale SG38

Posted: 07 Oct 2018, 21:26
by Martin G
Ooooooh! I will be following this build.

Re: Jilles Smits 1/3 scale SG38**

Posted: 13 Oct 2018, 21:00
by Peter Balcombe
The wood has arrived (for both the SG38 and ASK21), so I have just made a start on the rear fuselage :)
A lot of the spruce strip is for the SG38.

I have just cut the dozen or so core wooden parts for the rear fuselage structure, so will make those up into the basic framework (complete with Carbon strip strengthening) tomorrow.
Wood pile
Wood pile

Re: Jilles Smits 1/3 scale SG38

Posted: 14 Oct 2018, 12:36
by Barry_Cole
Booo, killjoy..

:evil: :evil: :evil: :evil:

Re: Jilles Smits 1/3 scale SG38

Posted: 15 Oct 2018, 22:27
by Peter Balcombe
First up in the build is the rear fuselage frame.
This is built up with the top, rear & bottom rails laminated from various lengths of spruce & thin carbon strip as can probably be seen from the cross sectional liquorice allsort stripe appearance in the pic.
The top & bottom rails will plug into the rear of the forward fuselage 'A' frame assembly.
There are still numerous diagonals, gussets, sheave mountings etc. to be added.

Re: Jilles Smits 1/3 scale SG38

Posted: 20 Oct 2018, 16:34
by Peter Balcombe
Rear fuselage construction now complete apart from metal fittings and tailplane fixings.

I am now moving on to the forward fuselage where the first job has been to make up a steam bending template for the box structure lower rails. Once the rails have been shaped, the basic structure should go together pretty quickly.
Rear fuselage nearly complete
Rear fuselage nearly complete

Re: Jilles Smits 1/3 scale SG38

Posted: 28 Oct 2018, 09:27
by Peter Balcombe
Moving on to the forward fuselage, the plan advises starting by building up the basic fuselage box structure as shown on a section of the drawing.
I started by splicing together lengths of standard 36" long spruce to make the curved lower rails, then steam bent these to shape with the aid of a simple MDF sheet template (profile taken from edge of a laser cut side sheet).
The various laser cut formers etc. are then glued into place to make the basic structure.
The shaped hardwood nose block holds the tow release pin guide tube and has slots to take a 12x12x2mm aluminium U channel.
The photos show the structure placed in a mirror image jig to hold the lower rail in shape whilst glued to the formers. (the yellow tape is used as a release layer to prevent the rail from sticking to the template.)
The other photo shows the assembly less laser cut the top & bottom sheets which will be added once the aluminium channel has been fitted up front.
Fuselage in lower rail jig
Fuselage in lower rail jig
Structure less top & bottom
Structure less top & bottom

Re: Jilles Smits 1/3 scale SG38

Posted: 28 Oct 2018, 09:32
by VinceC
Looking quite interesting and great work again from Jilles

Re: Jilles Smits 1/3 scale SG38

Posted: 30 Oct 2018, 10:35
by Peter Balcombe
Fuselage lower box structure now assembled to the state shown on the plan for the initial assembly.
The release servo position is up front & the rudder servo just behind. The elevator servo will be mounted in the seat base. All servos will be hidden by the fuselage side plates/seat base in due course.

Next step is to start constructing the 'A' frame parts.
Fuselage box from RHS
Fuselage box from RHS
Fuselage box from LHS
Fuselage box from LHS
Forward part
Forward part

Re: Jilles Smits 1/3 scale SG38

Posted: 03 Nov 2018, 11:08
by Peter Balcombe
Mast assembly construction has progressed to the point where I can check how the rear fuselage fits.
A slight hiatus on the forward part of the mast whilst we sort out a couple of missing tabs slots to enable the wing assembly to interlock correctly.
(CAD doesn't always produce what is expected!)

Its probably worth noting that there are an awful lot of wooden pieces which need to be assembled to make up the overall fuselage, so a builder needs to be very careful to make sure he carefully notes all of the drawing notes and supplied cross-sections to make sure the various items are assembled in the right order and place.
Jilles has done a very good job in providing a detailed plan which appears to mimic the full size construction and finished appearance.
Initial mast Assy + Rear fuselage
Initial mast Assy + Rear fuselage