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SHORT BROS NIMBUS SCALE 1:3.5

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

Post by Jilles »

Time for a new glider project for myself. I always wanted to built a gull wing glider but not one that is very common. When Cliff Evans requested a scale 1:3 design of the Short Bros Rochester Nimbus my choice was made. Only one ever was built and is still somewhere but in a very sorry state.
Over time I will add to this built thread as I progress with the built. it will not be a fast built so be patient. Attached pictures of the horz. stab and elevator assembly to-date
I want the tail bit first so I can check everything is square and level when the fuse is built.
For redundancy the elevator is two (2) independent halves each with their own servo built in the stab. Each servo will have a separate channel on the TX
plywood nc parts stab
plywood nc parts stab
false L/E  prepared  for lap joint
false L/E prepared for lap joint
test fit and assembly of stab centre section
test fit and assembly of stab centre section
test fit of both elevator servo's  other brand will be used
test fit of both elevator servo's other brand will be used
little bridges to retain outer lug of servo
little bridges to retain outer lug of servo
bridges fitted
bridges fitted
bottom spar glued to spar webbing
bottom spar glued to spar webbing
stab assembled
stab assembled
suggested balsa corner gussets
suggested balsa corner gussets
elevator halve assembeld
elevator halve assembeld

Jilles
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Joined: 22 Mar 2015, 10:27
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Jilles »

For those interested attached the 3-view drawing of the model design
3-view concept drawing of model
3-view concept drawing of model

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chris williams
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Location: Blandford Dorset

Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by chris williams »

Jilles, have you scaled up the drawing from 1:3.5?

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VinceC
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by VinceC »

This should be a very interesting build

Lawrie P
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Location: Townsville. North Qld

Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Lawrie P »

Hi Jilles,
Looking good.
Let the games begin...…….

Jilles
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Jilles »

Started on the fuselage. First I made all the metal parts so that is out of the way.. My son 3D printed the nose cone ( blue) and a internal nose cone (white). This last one will be used to make a plaster mold to cast the nose weight later. My home made tow release was tested inside the nose cone.The main former sub assembly with joiner sleeves was assembled together with a sub assembly of the tail parts. Then all fuse parts were dry fitted together to see if all is well and to determine the order of how the parts need to go together. Some parts required adding missing notches and some had some mods done to make life easier later, that is the fun of a first (beta) built.
These parts with modifications will be sent to Cliff Evans so the next builder is good to go.
3d printed nose cone(s)
3d printed nose cone(s)
metal parts
metal parts
wheel support brackets
wheel support brackets
test fit tow release
test fit tow release
assembly tail formers with tee nuts
assembly tail formers with tee nuts
assembly of major center former assembly
assembly of major center former assembly
center assembly complete
center assembly complete
all fuse parts dry fitted
all fuse parts dry fitted

Jilles
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Jilles »

95% of all NC fuse parts are now glued or epoxied together
The wing retaining bars with M4 tee nuts will be next together with teh wing stub end rib
now the fun starts with adding stringers and ply planking. this will slow the built a bit. A challenge will be the fairing of the wing stubs
For the wing stub design I had access to the original factory drawings thanks to Vince C. The factory drawing and picture of the original show some difference in that area. I will keep you posted on this subject when I get there.
front fuse glued
front fuse glued
rear fuse glued
rear fuse glued
fuse frame 95% complete
fuse frame 95% complete
wing retaining bars with tee nuts
wing retaining bars with tee nuts

Jilles
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Jilles »

Progress despite 35 degree heat wave . Main stringer S1 is bend and curved from former F10 forward. Instead of steaming the 3/8"X3/16" stringer is split with a knife, then glued into place. Glue is also applied to split surfaces, this way there is no high tension in bending S1.
Fin structure added.
6X6 mm balsa cross braces added between main stringers S1 at every former from rear of wing to tail. (anti squeeze bars)
Wing stub parts added including wing retainer plates with M4 Tee nuts
Test fitted an electrical plug for elevator servo wiring. This is a personal feature. I do not like loose servo wires for every servo. On he field swapping plugs or reversing is always possible. Type of plug is to builders preferences. plug will be hidden under future cap on top of Horz. stab.
Corner gussets in canopy area added to follow future canopy contour.
My drawing specifies 0.4mm ply planking for the fuse tail end. Due to the size of the fuse I now realize that it is a bit to flimsy. I decided to go for 0.8 mm plywood instead. Ply sheets are added two former bays long. Longer parts will be come more difficult to control during fitting.
The pictures show applying the 3rd ply sheet working from the tail end. Patterns are made from thin cardboard. Plywood cut with the pattern and lap joint contact area's sanded. I did not use the Iron on method for this built but glued the ply sheets direct in place instead. Cable ties are used to wrap the ply tight to the formers. When the cable ties are really tight 12x3 mm spruce bars are wedged under the cable ties to create extra pressure. Up to now this has worked fine. With the use of cable ties as shown the anti squeeze bars mentioned earlier are essential.
MAIN STRINGER SPLIT AT FRONT END
MAIN STRINGER SPLIT AT FRONT END
FIN FRAME ADDED
FIN FRAME ADDED
6x6 BALSA CROSS BARS ADDED
6x6 BALSA CROSS BARS ADDED
WING STUB PARTS ADDED
WING STUB PARTS ADDED
WING RETAINER PLATES WITH TEE NUTS
WING RETAINER PLATES WITH TEE NUTS
PLUG FOR ELEVATOR SERVO'S
PLUG FOR ELEVATOR SERVO'S
CORNER GUSSETS FOR  CANOPY FILLET
CORNER GUSSETS FOR CANOPY FILLET
CARD BOARD PATTERN 3RD SHEET
CARD BOARD PATTERN 3RD SHEET
PLY SHEET CUT AND LA[ JOINTS SANDED
PLY SHEET CUT AND LA[ JOINTS SANDED
3RD PLY SHEET GLUED TO FUSE
3RD PLY SHEET GLUED TO FUSE

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VinceC
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by VinceC »

Going together well Jilles

Jilles
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Re: SHORT BROS NIMBUS SCALE 1:3.5

Post by Jilles »

I hope to get a weight of approximate 12 kg in total. But with the short nose there will be a substantial piece of lead required in the nose, so who knows.
No to afraid of it. The Zephyrus of Vince is 15 kg at the same scale. We have a 6m Ka8 flying (Phoenix with substantial mods to keep it together in flight) in our scale group at 18 kg. Despite this it does not come down in a hurry. All to do with wing area of course.

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