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SZD-8 Jaskolka 1/3 Scale**

Let us all watch your new project progress.
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Cliff Evans
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Re: SZD-8 Jaskolka 1/3 Scale**

Post by Cliff Evans »

https://lasercutsailplanes.co.uk
https://patteaklegliders.co.uk
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Peter Balcombe
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Location: Clevedon, North Somerset, U.K.

Re: SZD-8 Jaskolka 1/3 Scale**

Post by Peter Balcombe »

Twin rudder horns made & fitted in balsa support block plus rudder LE profiled, so a mandatory hingeing check with forward pin hinges part dry fitted into the fin post.

Rudder hinge check
Rudder hinge check

Ply cap strips yet to be fitted, plus optional rudder light bezel.
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Cliff Evans
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Re: SZD-8 Jaskolka 1/3 Scale**

Post by Cliff Evans »

Elevator test


https://lasercutsailplanes.co.uk
https://patteaklegliders.co.uk
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Peter Balcombe
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Location: Clevedon, North Somerset, U.K.

Re: SZD-8 Jaskolka 1/3 Scale**

Post by Peter Balcombe »

Work has been progressing on the tail & these are now virtually ready for the covering stage.
The rudder top has been revised to take a 3D printed clear glass effect rudder light fitting (unlit due to relatively dim bulb fitted on full size for night flying only).
A thin surround will be fitted over the light in due course to represent the full size attachment cover.

Rudder hinged
Rudder hinged
Rudder light mod
Rudder light mod

Meanwhile, the tailplane & elevator have now been skinned & finished off ready for covering.

Finished tailplane assemblies
Finished tailplane assemblies
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Peter Balcombe
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Re: SZD-8 Jaskolka 1/3 Scale**

Post by Peter Balcombe »

Back to the wing now.
Using the ply flap & aileron shroud templates as a guide, balsa strips were added using Aliphatic glue & then the shroud profiles sanded using a 12” long length of 3/8” dowel with 120 grit emery paper glued to make a long round file.
With the balsa sanded down flush with the ply templates, the control surfaces fit nicely.

The brass tubes which take the aileron hinge barbs have also been epoxied into place with the ailerons in situ. to ensure correct positioning - the tubes being pushed back to ensure maximum barb engagement.
The photos below show how the tubes project behind the shroud line.
The current gap between the inner & outer ailerons will be reduced by adding a doubler to one end riblet.

The flap was refitted (using bolts again) to check shroud fit & operation. A 25mm section has been removed from both shroud & flap LE at each track position to allow the pairs of track holes to be accessed, but I realised that the shroud could be left intact if the flap is attached in the extended position, so this will now be replaced.
A previously mentioned, 3 keeper sections of flap LE will need to be able to fitted on final flap assembly in order to retain the ball link on the actuation pin. These can either 3D printed or could be end sections of a full balsa sanded LE, temporarily removed after LE sanding to allow fixings to be put into place until final assembly.

The upper D box skin has also been added over the whole wing using 0.6mm ply. The 0.6mm ply is much more resistant to finger damage during handling/rigging - although it currently seems to be expensive & hard to find :(
As it comes in 50” Sq. sheets, the wing can be done with just a single spanwise joint.
Note that I have initially sheeted to halfway across the 1/2” wide main spar in order to apply the rear sections separately. (The upper outer rear section has 2 top aileron horn pushrod penetrations & the inner bottom rear sheet prevents further access to the flap actuation linkage).

Aileron hinge barb tubes
Aileron hinge barb tubes
Twin aileron ends
Twin aileron ends
Inner flap track
Inner flap track
Centre flap track
Centre flap track
Outer flap track
Outer flap track
Ailerons in place
Ailerons in place
Inner D box top skin
Inner D box top skin
Outer D box top skin
Outer D box top skin

Note that the aileron hinges are not fully pushed into their tubes in the above outer wing pic. Hence the strange TE line!
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Peter Balcombe
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Location: Clevedon, North Somerset, U.K.

Re: SZD-8 Jaskolka 1/3 Scale**

Post by Peter Balcombe »

Trial fitted some simple non-tapered (25mm long) LE profile sections for each of the 3 flap track positions.
These will probably need a small rebate notch at the track end to accept the rear of the ball-link moulding.
In hindsight, the ball-link probably cannot move sideways enough to come off the brass actuation pin due to it being restrained by the width of the vertical slot in the rear spar web - just forward of the flap LE :)
However, access to the rear brass slide pin is still required to insert this & hence the gap needs to be filled once done - unless you want to leave a 21mm+ gap in the LE adjacent to each slide :o

Outer flap LE insert
Outer flap LE insert
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Peter Balcombe
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Re: SZD-8 Jaskolka 1/3 Scale**

Post by Peter Balcombe »

Upper root end rear skin section now fitted, airbrake released, then airbrake cap strip glued in place.
The wing cables have also been cut & fitted with an 8 pin MPX type connector at the root.
The step in rear of skin is where the flap shroud ends - aileron shroud is slightly smaller than flap at this point.

Upper root skins
Upper root skins
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B Sharp
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Re: SZD-8 Jaskolka 1/3 Scale**

Post by B Sharp »

I am glad that it's you and not me trying to set that all up Peter. Well done that man!
Brian. :o
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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: SZD-8 Jaskolka 1/3 Scale**

Post by Peter Balcombe »

1st wing D box now skinned & spruce strip hatch openings put in for flap & brake servos.
8 pin MPX connector receptacle also mounted on a plate in fuselage wing root with internal harness to reach to the expected Rx location behind the pilot seat.

Root D box
Root D box
Tip D box
Tip D box
Wing root connector
Wing root connector

The wing just needs the retention tongue fitted into the root rib & it will be time to take a stiff drink before closing up the rear root section, complete with flap actuation linkage & airbrake opening!
I think that I will need to make the brake opening in a sheet & then finally fit to suit that ;)

The LE can now be added (1/2”, with 1.5” wedge at root). I’m thinking of making this with a 1/4” hardwood face to help reduce impact damage in view of the likely flying sites! The wings will be glassed using lightweight cloth (except for control surfaces) so this should also help.
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Peter Balcombe
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Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: SZD-8 Jaskolka 1/3 Scale**

Post by Peter Balcombe »

1st wing now completely skinned & the flap mechanism & airbrakes still seem to work :)
Lower root skins
Lower root skins
Lower top skins
Lower top skins


All 4 wing servo apertures have also been released ready for simple skin ply thickness covers - which on this model have no pushrod penetrations as the ailerons are actuated by top mounted horns, so penetrate the top skins.
The full size (at least on SP3675) appears to have a single aileron pushrod shroud on the upper wing surface as the single/split aileron horn(s) is located at roughly the centre of the overall aileron length.


The model has separate servos & top horns for inboard & outboard sections, so 2 pushrod exits & shrouds are needed.

Although I have previously used the free online TinkerCad application for making simple 3D shapes, I thought I would try Fusion 360 (free online tool for non commercial/personal use) as this allows objects to be created by ‘lofting’ between 2 or more shapes (in this case, 2 half ellipses + half a racetrack shape) to create a solid which could then be hollowed out (shelled) & the bottom chopped off to give the required result. A bit of a learning curve, but lots of videos to help 8-)
The results appear to come out well when printed on my simple 3D printer & seem to be a decent fit :)
(The 3D solid object could probably alternatively be used as a pattern to create plunge moulded or vac-formed items)

3D printed shrouds
3D printed shrouds
Dry fitted shroud
Dry fitted shroud
Last edited by Peter Balcombe on 27 Dec 2021, 19:58, edited 1 time in total.
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