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Scratch built Pilatus B4 to 1/4 scale.

Let us all watch your new project progress.
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B Sharp
Posts: 736
Joined: 19 Mar 2015, 17:18
Location: Perthshire

Re: Scratch built Pilatus B4 to 1/4 scale.

Post by B Sharp »

Something always goes wrong! Last night I trimmed all the parts that I had glassed then turned them over and glassed the other sides. Today I checked them out only to find I had put 2 coats of glass on the left side of the rudder and none on the right. Duhhh! :oops: :oops: :oops:
Brian.

Jolly Roger
Posts: 418
Joined: 30 May 2015, 20:35
Location: Sutton Bank, North Yorkshire

Re: Scratch built Pilatus B4 to 1/4 scale.

Post by Jolly Roger »

Now I would NEVER do anything like that. ;) says the man who falls off seats. :oops:
You could just glass the other side twice too (I have this thing about symmetry). I’m sure the rudder could use a little extra glass, with the usual slope side wear and tear. I reckon the second layer of glass adds less than 3g at the back.

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B Sharp
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Location: Perthshire

Re: Scratch built Pilatus B4 to 1/4 scale.

Post by B Sharp »

I really don't need another 3gm at the tail end Rog!
Brian :oops:

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VinceC
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Re: Scratch built Pilatus B4 to 1/4 scale.

Post by VinceC »

Signs of old age creeping up. Don't worry as it only gets worse

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RobbieB
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Re: Scratch built Pilatus B4 to 1/4 scale.

Post by RobbieB »

:lol:

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B Sharp
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Location: Perthshire

Re: Scratch built Pilatus B4 to 1/4 scale.

Post by B Sharp »

In the last few days I have tackled the wing roots and fairings of the fuselage. My workshop is not large enough to have both wings attached to the fuselage and still have room to work round about it so proceedings were transferred to the dining room table (with the kind permission of Mrs S).
The airframe was assembled with the wings resting on two large boxes and the fuselage hanging between. An incidence meter was attached to wings and tailplane and this showed a decalage angle of 2.2 degrees (quick nod to Antonia) which will do quite nicely thank you. Once fuselage, wings and tailplane were all squared up the inner wing root ribs were attached to the fuselage with epoxy and thin ply forms. Once disassembled and back in the workshop the gaps between the ribs and the fuselage were blocked in with balsa then covered in “Epol” filler before lots of careful sanding. I am quite pleased with the finished result. :) :) :)
The next job will be to wet and dry the glass on the whole fuselage and then the wings – not a job I am looking forward to.
Brian. :?
Attachments
Wing roots during set-up.
Wing roots during set-up.
The finish product.
The finish product.

Jolly Roger
Posts: 418
Joined: 30 May 2015, 20:35
Location: Sutton Bank, North Yorkshire

Re: Scratch built Pilatus B4 to 1/4 scale.

Post by Jolly Roger »

Looks really smart Brian. What's your wing joiner?

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B Sharp
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Joined: 19 Mar 2015, 17:18
Location: Perthshire

Re: Scratch built Pilatus B4 to 1/4 scale.

Post by B Sharp »

Hi Rog. It's a 14mm carbon rod in 16mm carbon tube. This should be more than man enough for a 1/4 scale model, even taking into account my occasional hooligan episodes.
Brian. :)

Jolly Roger
Posts: 418
Joined: 30 May 2015, 20:35
Location: Sutton Bank, North Yorkshire

Re: Scratch built Pilatus B4 to 1/4 scale.

Post by Jolly Roger »

B Sharp wrote:
10 Jun 2020, 17:36
Hi Rog. It's a 14mm carbon rod in 16mm carbon tube. This should be more than man enough for a 1/4 scale model, even taking into account my occasional hooligan episodes.
Brian. :)
Yeah, that should do the job! I found it impossible to break a 12mm carbon rod in a 5kg, 4m model by aerobatics alone. I needed a hillside to do the job properly. ;)

So you should have a decent margin. In theory a 14mm rod is nearly 60% stronger than a 12mm rod, as section modulus goes up with the cube of diameter.

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B Sharp
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Location: Perthshire

Re: Scratch built Pilatus B4 to 1/4 scale.

Post by B Sharp »

Rog, section modulus is a term I haven't heard or used since my early 20s and at college.
Brian. :)

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