1/3 Scale Harbinger 2

[Peter Balcombe]

Back to the fuselage to prepare the wing strut pickup bracket for installation by fitting the short lengths of 3/16” brass tube bushing & then securing in position with 4off M3 bolts & nyloc nuts as shown below.

Wing strut pickup brackets

Fuselage installation showing M4 strut fixing

Front view of M3 fixing bolts

[Peter Balcombe]

Cliff & I have been refining the fin shroud 3D print during the past few days & now have 2 half-shells which fit within the assembled CNC ply structure & can be glued in so that the outer surfaces are more or less flush.

Fin shroud shells fixed

Meanwhile, the 2 lower stabiliser skins are now in place, with just the tip blocks to add & LE to finish off.
The shot below shows the underside of the stabiliser so far, together with elevator halves & servos sat in position to show the approximate servo linkage runs. (The elevator LE has not yet been profiled & I didn’t align the pin hinge location for the shot, so the elevator halves may not be as close as in reality.

Tailplane bits

Elevator servos in place

[catwok]

Looking good Pete, will the fin fairing be removable?

[catwok]

Stoopid question, of course itcwl be! How will it be retained?

[Peter Balcombe]

Not really thought about it yet
Possibly a peg or two to locate at the rear & a central magnet at the front?
Depends how easily it can be slid in from the front when skinned stabiliser & fuselage skinning is in place

[Peter Balcombe]

Fuselage skinning started, with upper section of the 0.8mm done (nose to Former 11 - wing rear incidence peg) and the remaining 0.6mm to tail started.
There is a little bit of ‘hungry horse’ effect on first section but that will be filled when the nose cone is finally fitted & faired in.

Forward upper skin

Wing root area

Meanwhile, a further set of 3D printed fin fairing halves have been made which fit flush to the ply core structure outline. With the stabiliser now skinned, the fairing fit can be checked.

Stabiliser & fin fairing

[Peter Balcombe]

Upper fuselage skinning now complete & the assembly removed from the building jig.
With access now available to the lower fuselage, the skid side plates has been added, whilst at the tail, the 0.4mm ply fin skins are in the process of being glued in place.
The fuselage will now be put to one side whilst the wings are built & available to rig & check the rear incidence pin fit before the tubes are fixed in place. (The tubes fit in th balsa infilled section of th fuselage wing root fairing).

Upper fuselage skinned

Strut attachment & wheel

Fin skins

Incidence tube area of root firing

[Peter Balcombe]

Wing assembly has started with the main spars which had previously been spliced up to make a 2950mm or so length (2926mm finished length) and the tip ends tapered in thickness as shown on the drawing.

First job, in my opinion, is to get the strut attachment brackets fitted. So with the position marked as per the drawing, the appropriate part of the rear spar web (W3A) was glued to the spar, followed by the hardwood spar infill SBK & then the short front web W5 - ensuring that the webs are slightly offset to allow the ribs to fit at the non right-angle angle wrt the spar. The web holes can then be used as markers to drill through the 3 brass attachment plate fixing holes.
Note that the plates are different in order to give a small skew to the strut attachment pin as shown on the drawing.
With the plates in place, I cleaned out the plate holes to take the brass bushing tube & soldered in a single piece spanning both plates (to ensure perfect pin alignment) before cutting out the tube section between the plates. Once the outer bush length has been adjusted as necessary & the cut edges cleaned its job done.

LH wing attachment from bottom

Attachment from top showing infill

The remaining outer web sections were then fixed in place & the wing dry assembly started to check fits. You will see from the photos below that my building room only just accommodates the wing panel!

LH panel root end

LH panel toward tip

[Elliot Howells]

superb! great to see such regular updates Peter!

Thanks, Elliot.

[Peter Balcombe]

The wing structure has now been glued together & all upper spars/spruce support strips fitted, apart from the main spar which will go in once the upper root spar doubler is in place.
The GRP wing joiner tube has just been epoxied into place, so the spar doubler is next.

Tip end from brake box

Root end with joiner tube

Root end