Slingsby T.50 Skylark 4

Let us all watch your new project progress.
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B Sharp
Posts: 572
Joined: 19 Mar 2015, 17:18
Location: Perthshire

Re: Slingsby T.50 Skylark 4

Post by B Sharp » 18 Dec 2018, 23:16

Robbie, the braced aileron is faced with 1/32 ply. The one furthest away is yet to be completed, I.e no leading edge facing.
Brian. :cry:

John Vella
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Joined: 20 Mar 2017, 22:09
Location: UK

Re: Slingsby T.50 Skylark 4

Post by John Vella » 19 Dec 2018, 12:22

Brian, maybe the construction of my long MU13 aileron might help. The aileron is 3ft 7in long and 2 in plus wide. The facing is from 1.5mm Balsa on 5mm sq spruce. The front box is top and bottom 0.4 mm ply. The TE is balsa /0.8mm ply/balsa sandwich. The cap strips are 0.4mm ply. The structure is torsionaly stiff and weighs 3 ozs. Regards John.
Attachments
20181219_115529.jpg
Root view.

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B Sharp
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Location: Perthshire

Re: Slingsby T.50 Skylark 4

Post by B Sharp » 28 Dec 2018, 16:06

While I continue to ponder the way forward with the ailerons I decided to get the fuselage finished to the point of painting.
The glass/epoxy covering to the fuselage was rubbed down with wet and dry. Upon inspection there were a number of holes and other flaws all over the surface as well as patches of open weave. I was interested in the thread on filler elsewhere on the forum and was surprised to read that it was possible to thin P38 filler. I scraped P38 into the worst of the defects and gave then a quick sanding. I then thinned a large batch of filler, mixed in the red hardener and then painted a thin coat of filler all over the fuselage. I gave a second coat over areas which I felt it was required before the first coat set. After another session with the wet and dry I was very happy with the final finish which is now ready for primer.
I have now also added the nose skid and tail skid to the fuselage and have started to fair these into the fuselage underside.
On Mike’s plans he stipulates adding 1/64 ply covers over the wing/fuselage joint just aft of the wing mounting area. I decided to use 1/32 ply for these in the interest of durability and adjusted the shape to get a more desirable line. I have still to add a little glass cloth reinforcement to the underside of these and also to fair in the top of the joint with filler but they should be ok in operation.
Brian. :)
Attachments
SL4_54.jpg
The nose skid in place.
SL4_55.jpg
The tail skid.
SL4_56.jpg
Aft of wing covers being attached.
SL4_57.jpg
Aft of wing covers.
SL4_58.jpg
Aft of wing covers.

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

Re: Slingsby T.50 Skylark 4

Post by B Sharp » 30 Dec 2018, 16:25

Well, I've been and gone and made up my mind on the ailerons.
Today I have carved a new aileron from a length of 2 inch by 1/2 Balsa TE stock. Once it was fully shaped I clamped one end of the built up and also the solid aileron to the bench and then applied approx. equal amounts of torsional force to each. The built up and reinforced aileron had a twist of +/- 30 degrees. Under similar pressure the solid aileron had a twist of +/- 5 degrees. Sorry folks, but that is "No Contest" to me.
On the negative side it is not a scale structure and it weighs double the built up structure. On the positive side it is less likely to flutter if I get the aeroplane going a bit fast and also at 50ft no-one will ever notice (except maybe the Scale Police).
Brian. ;) ;) :)

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B Sharp
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Location: Perthshire

Re: Slingsby T.50 Skylark 4

Post by B Sharp » 08 Jan 2019, 20:02

Well, my last post was in 2018 and it is now a brand spanking (am I allowed to say that?) New Year. So I will start of by wishing you all a Very Happy New Year.
I have not been idle over the festive (falling down) season. I have completed the ailerons and covered the centre section of the wing and also the wing tip panels with white “Profilm” and snazzy coloured wing tips. I made epoxyboard horns for the ailerons and got them all hooked up with the minimum of fuss. The servo hatches were formed from 1/32 ply with a “Profilm” covering. Job Done!
My next job will be to attach the canopy glazing to the frame. This is always a fiddly job and is one I always dread, it is just so easy to make a mess.
Brian. :)
Attachments
SL4_59.jpg
The completed and covered wing panels.
SL4_60.jpg
Tip panel detail showing the servo hatches.
SL4_61.jpg
Pushrod / horn detail.

Geoff Pearce
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Joined: 18 Mar 2015, 09:11
Location: SN11 9EE

Re: Slingsby T.50 Skylark 4

Post by Geoff Pearce » 08 Jan 2019, 22:50

Hey Brian I was lead to believe you didn't make a mess? :lol: :lol: :lol: :lol:

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chris williams
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Location: Blandford Dorset

Re: Slingsby T.50 Skylark 4

Post by chris williams » 09 Jan 2019, 00:33

Profilm, Brian...? Did you take out a mortgage? :D

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B Sharp
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Location: Perthshire

Re: Slingsby T.50 Skylark 4

Post by B Sharp » 09 Jan 2019, 08:52

Geoff, I am very good at making a mess, I do it all the time. However I am also very, very good at clearing up afterwords.
Chris, I know that profilm is pricy but I love working with the stuff. I have tried most of the alternatives but profilm is still my favourite.
Brian :)

john greenfield
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Re: Slingsby T.50 Skylark 4

Post by john greenfield » 09 Jan 2019, 09:15

B Sharp wrote:
09 Jan 2019, 08:52
Chris, I know that profilm is pricy but I love working with the stuff. I have tried most of the alternatives but profilm is still my favourite.
Brian :)
Brian
Have you changed nationality !!!!!

AEB
AEB = Aeronautical Energiser Bunny (with thanks to CW)

StephenB
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Joined: 26 Dec 2018, 08:45
Location: Hungary

Re: Slingsby T.50 Skylark 4

Post by StephenB » 09 Jan 2019, 09:17

A very nice job Brian, are the ailerons simply top hinged with tape?

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