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Ply skins

If you need help on creating or dealing with a plan in dxf or other formats, then this is the place to ask.
John Treble
Posts: 14
Joined: 13 Jan 2021, 11:08
Location: Lyme Regis

Ply skins

Post by John Treble »

Has anyone ever tried cutting out 1/64th ply skins for a non-square section fuselage?
Following my posts last year, I’ve made much progress with my first CAD project, which is to be a BAC VIII waterglider. I am almost ready to prepare my design of the tail boom for cutting, but I think it is true to say that nowhere have I seen any mention description of cutting sheet material that is intended to be wrapped around a framework. I’ve made a fuselage this way before by cutting card templates to determine the shape, and it seems to that for a system like Fusion 360, the maths involved shouldn’t be too difficult. My tail boom has an elliptical section with constant taper.
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Cliff Evans
Posts: 1029
Joined: 29 Dec 2019, 15:13
Location: Bristol
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Re: Ply skins

Post by Cliff Evans »

John, I personally think you would be better off sticking to the cardboard template way.
https://lasercutsailplanes.co.uk
https://patteaklegliders.co.uk
sp250
Posts: 23
Joined: 30 May 2022, 18:06
Location: Shropshire

Re: Ply skins

Post by sp250 »

It's still CAD that way isn't it? ;)
John M
Barry_Cole
Posts: 98
Joined: 26 Jun 2022, 00:51
Location: Hampshire

Re: Ply skins

Post by Barry_Cole »

sp250 wrote: 05 May 2023, 09:17 It's still CAD that way isn't it? ;)
John M
Cardboard Aided Design....

:lol: :lol: :lol: :lol:

BC
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Peter Balcombe
Posts: 1399
Joined: 18 Mar 2015, 10:13
Location: Clevedon, North Somerset, U.K.

Re: Ply skins

Post by Peter Balcombe »

John,
I always use cardboard templates when ply skinning up to 1/models& using 0.4- 0.8mm ply. I also generally add an 1/8” balsa strip to the formers at the ply skin section joint Ito increase gluing area, as well as chamfering the joint edges to increase ply/ ply bonding areas & reduce the external edge “step”.I generally use the ironing technique with white glue to fix the skin sections in the correct place, then glass the external surface to increase “ding” resistance.
This technique has been used on the 1/3 scale Oly. Jaskolka & is now being used on the current Harbinger build.
Peter
AdamChambers
Posts: 23
Joined: 09 Jun 2023, 17:50
Location: Southampton

Re: Ply skins

Post by AdamChambers »

Stick with cardboard templates.. why.... having pre cut skins sounds awesome but requires building to be perfect. If you did design them, give yourself a 3mm overlap at critical places so you can trim to fit.
Tom Pack
Posts: 88
Joined: 18 Mar 2015, 23:33
Location: USA

Re: Ply skins

Post by Tom Pack »

Depends on the part…..fuselage parts I always make card stock templates…..aileron skins for built up wings I always CAD draw with an extra 1/4” added to the leading edge and have them laser cut…..so much easier then cutting and fitting cap strips!
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