MU13 Charlesworth

Let us all watch your new project progress.
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Scale Police
Posts: 32
Joined: 05 Nov 2017, 10:36
Location: World

Re: MU13 Charlesworth

Post by Scale Police » 10 Jan 2019, 17:27

John Vella wrote:
10 Jan 2019, 16:36
The next little job is fitting and shaping the leading edge. It is from 4ft long 6mm medium hard balsa. Aliphatic resin was used and pinned in place . The profiling started with the trusty David Plane then sanding with the butting sheet ply protected with insulating tape. The Gottingen 540 profile is pretty blunt and crude by modern day standards, but does the job and is scale. (Scale Police take note). Next the wing tips were profiled with the 0.4 mm ply blending into the balsa. The final constructional job was the root rib facings made from 1.6 birch ply, and made in 2 sections to account for the bend at the canopy cut out. On offering up the wing on its joiners the fit looked pretty good. The starboard wing including servos comes out at 38 ozs. On most of my gliders the wings weigh about half the gross weight of the complete model. So it looks like a target weight of around 10lbs might be achievable.
Noted!

John Vella
Posts: 166
Joined: 20 Mar 2017, 22:09
Location: UK

Re: MU13 Charlesworth

Post by John Vella » 18 Jan 2019, 11:13

This an update on the slow build of the MU13 wings. The problem I am finding is the time taken in reprofiling the wing ribs. The humps and bumps occur on the top rib surface only on the plans which the Laser Cutting follows exactly. The strange thing was the fuselage and empenage were very accurate, and went together a treat. I like a challenge but the time taken to reprofile the ribs is testing my patience. What would we do without the trusty Straight Edge and a good set of Glasses? Hopefully the MU13 will fly in the Spring of this Year.
Attachments
20190118_103330.jpg
Wing rib 8 is typical of the problem top surface.

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

Re: MU13 Charlesworth

Post by B Sharp » 18 Jan 2019, 11:57

John, the straight edge is mandatory but the glasses must be filled with a good malt whiskey.
Brian. :D :D :D

John Vella
Posts: 166
Joined: 20 Mar 2017, 22:09
Location: UK

Re: MU13 Charlesworth

Post by John Vella » 18 Jan 2019, 18:45

Brian a glass of Glenmorangie would not go amiss after this build. 😁😁

John Vella
Posts: 166
Joined: 20 Mar 2017, 22:09
Location: UK

Re: MU13 Charlesworth

Post by John Vella » 17 Mar 2019, 17:27

Here we go again ,with the forecast showing Spring returning soon and flying weather, is an update on the left wing build. I decided to construct the rear structure to the spar first and build the front ribs afterwards on the second wing. The false leading edge is 2 mm medium hard balsa .The front root rib was partially cut through for the cockpit angle ,and jigged on the fuselage rib to get exact alignment before fitting on the wing and glued. The trailing edge and tips were the balsa 0.8 mm ply balsa laminate. All ribs were reprofiled in situ.
Attachments
20190202_140711.jpg
Rear ribs and trailing edge fitted
20190203_122805.jpg
Tip view of rear structure
20190217_205530.jpg
Front ribs added
20190217_205655.jpg
Root awaiting front rib.
20190303_122945.jpg
Front rib jigged to fuselage for algnment
20190317_141733.jpg
Front rib glued into place
20190317_142043_001.jpg
Wing with false LE fitted and profiled
20190317_141925.jpg
Wing tip profiled and gussets added.

John Vella
Posts: 166
Joined: 20 Mar 2017, 22:09
Location: UK

Re: MU13 Charlesworth

Post by John Vella » 13 May 2019, 12:43

With flying weather arriving the build is progressing slowly. The fitting of the 5mm × 3mm spruce drag spars are next. Then the 1.5mm ply inter rib webbing. On this wing there is continuous webbing between rib 2 and 3 with a slot for the rear brass box. The brass box is loose fitted ,.then the left wing is mounted and jigged with the fuselage and right wing. The brass box is glued in position with 30 minute epoxy. Care was taken with wing root alignment to allow for spacing when the ply facing rib is fitted. The next job is the 1.5mm ply boxing the rear incident box. Then the skinning of the left wing will commence.
Attachments
20190502_153322.jpg
Drag spars and webbing fitting.
20190513_112814.jpg
Wings rigged on fuselage.
20190513_113640_001.jpg
Wing jigged with gap for facing rib.
20190513_113745.jpg
Brass box glued in position.
20190513_113825_001.jpg
View from right wing tip.

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