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SHORT BROS NIMBUS SCALE 1:3.5

Let us all watch your new project progress.
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Jilles
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Joined: 22 Mar 2015, 10:27
Location: Australia
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Jilles »

More Ply planking done to the fuse. closing in on the nose area. Compound curves so a bit more clamping force is required but so far so good
The planking is at the moment only at the top only with the main side stringer as guide. Except on top of the wing stub. The fairing radius is very large and reached nearly to the main stringer, In that area the ply was extended a bit lower When all top planking is done I can remove the fuse from the base and turn over for the bottom planking.
A 5 mm balsa support base is added between formers and stringers of the nose top. To much of a compound curve ply +/-8 mm wide tapered strips will be fitted here
F028.jpg
F029.jpg

Jilles
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Jilles »

Progress again. Need to divide time for building the Nimbus and vintage glider designs for others.
The horizontal stab was planked top & bottom with 0.4 mm ply using the iron on method.
Test fitted the stab to the fuse and a frame was made for a top fairing. This is to builders preferences, no detail on the drawings for this. 3M magic tap to the top of the stab prevents the fairing frame to be glued to the stab. the fairing or cover has a 1/8" dowel at the front and a servo screw will retain the rear end onto the stab.
I will use a single plug and socket for both elevator servos. One channel each. This is as mentioned earlier a personal choice. other ways could be used.
I do like one plug, When the wires are soldered in the correct way in the first place no chance one have a mix up at the field or reverse the servo plugs.
The fairing was also planked with 0.4mm ply wood and the shape extended to the bottom of the fin structure with balsa. The fin also has 0.4 mm ply planking
filler and sanding will finish this area later .
I made some temporary stands so I can turn over the fuse. The front stand is located over the main former assembly, the rear is held in place buy two M4 socket head bolts , the same that will retain the stab in future
The fuse is now turned over and the building support stands on the bottom of some formers can be removed. An other planking session is now coming up after some work on the interior
planked stab test fit
planked stab test fit
fairing frame
fairing frame
check wiring plug
check wiring plug
fairing complete
fairing complete
brackets fabricated
brackets fabricated
F035.jpg
F036.jpg
fuse turned over
fuse turned over
ready to remove former stands
ready to remove former stands

Lawrie P
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Joined: 18 May 2017, 21:06
Location: Townsville. North Qld

Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Lawrie P »

Looking good Jilles.
Have to agree with Cliffs comments at top of the page.

Lawrie.

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VinceC
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by VinceC »

Nice to see the fuselage coming together so well. How are you feeling now about the unusual geometrics of the wing stub and wing attachment?

Jilles
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Jilles »

The wing stubs on the fuselage will be interesting. Now I have the fuse together and see the size of it all there are have several ideas. Depending on the way I will get it together there may be some parts added to the cutting list for potential future builders to make it a bit easier. First the bottom planking needs to be added to the full length of the fuse then the stubs will be next.

Jilles
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Jilles »

Some progress again, before planking the bottom of the fuse the two elevator servo wires were fitted as well as the pull-pull cables for the rudder
It would be nearly impossible to get these in place with planking fitted. Because of the long length of the pull-pull cables I added a support half way
(picture F040). the space between the first two fuse formers packed at the bottom with balsa to support ply strip planking. Due to high tension the front ply parts were fitted with cable ties to keep the parts in place during curing of the glue. The Iron on way would not work due to the high tension in the ply.
Additional support was added in bottom wing stub to support future ply planking in the form of balsa strips
The leading edge of the wing stub formed with solid balsa, this does not include future fairing radius to fuse surface planking.
servo wires an p-p cables fitted
servo wires an p-p cables fitted
p-p cable support half way
p-p cable support half way
balsa support for ply strip planking
balsa support for ply strip planking
clamping sample of front ply sections
clamping sample of front ply sections
front planking completed
front planking completed
support formers in wing stub bottom
support formers in wing stub bottom
L/E to wing stub
L/E to wing stub

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VinceC
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by VinceC »

That is quite some model, quite an engineering task, but the results are going to be good

Jilles
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Jilles »

Planking of the wing stubs has started. Bottom first because this side is relatively easy. It does not have the severe compound curves as the top does. attached pictures show how ply sheets were added and in what order.
The tail structure that will support the skid was prepared for planking, M3 Tee nuts or blind nuts depending where you come from are put in place to fit the tail skid later. My plan is to use nylon screws and hope they will shear if I manage a ground loop and not cracking the tail section.
rear ply sections in place
rear ply sections in place
rear view stub
rear view stub
center section with wheel opening in one piece
center section with wheel opening in one piece
bottom ply planking complete
bottom ply planking complete
tail skid support structure ready for planking
tail skid support structure ready for planking
M3 nuts in place
M3 nuts in place

Jilles
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Location: Australia
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Jilles »

There were several option in my mind how to plank the top of the wing stubs with those compound curves. Lawrie Prest suggested one of my options and I decided to go with that one.
1/8" square spruce stringers were added as shown on attached pictures. they run from the Main fuse former to trailing edge. To the front 4 mm balsa sheet was used due to the strong curve .
A 6 mm balsa support was added 20 mm from the outer rib, this area is in line with the wing surface until the fairing radius starts
20 mm wide 0.4 mm plywood strips are now added as shown with a cross grain.
I use Quick Set PVA for this job. One can remove the clamps after 10 minutes so it does not have to be that time consuming I do however wait 30 minutes
The clamp holds the ply down from rib to the 6 mm balsa support to make sure this area is flat following the wing surface
every strip needs to be test fitted to make sure it is close to the adjacent strip but a little gap is not so much of a problem
The strips follow the natural curve and only a pin here and there is required to hold things in place.
due to the strong curve at the front The strisp will be 12-16 mm wide
When the total stub is covered a second 0.4 mm ply layer will be fitted.
This are either strips with the same orientation but half a strip offset or say 6 mm wide strips perpendicular running the full length of the wing stub.
Keep you posted.
rear stringers fitted
rear stringers fitted
front stringer 4 mm balsa sheet
front stringer 4 mm balsa sheet
finished stringers
finished stringers
first 5 strips  in place
first 5 strips in place
F057.jpg

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

Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Peter Balcombe »

Very nice indeed Jilles.
Keep up the good work.
Peter

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