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MU13 Charlesworth

Let us all watch your new project progress.
John Vella
Posts: 209
Joined: 20 Mar 2017, 22:09
Location: UK

Re: MU13 Charlesworth

Post by John Vella »

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

John Vella
Posts: 209
Joined: 20 Mar 2017, 22:09
Location: UK

Re: MU13 Charlesworth

Post by John Vella »

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
Rear ribs and trailing edge fitted
Rear ribs and trailing edge fitted
Tip view of rear structure
Tip view of rear structure
Front ribs added
Front ribs added
Root awaiting front rib.
Root awaiting front rib.
Front rib jigged to fuselage for algnment
Front rib jigged to fuselage for algnment
Front rib glued into place
Front rib glued into place
Wing with false LE fitted and profiled
Wing with false LE fitted and profiled
Wing tip profiled and gussets added.
Wing tip profiled and gussets added.

John Vella
Posts: 209
Joined: 20 Mar 2017, 22:09
Location: UK

Re: MU13 Charlesworth

Post by John Vella »

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
Drag spars and webbing fitting.
Drag spars and webbing fitting.
Wings rigged on fuselage.
Wings rigged on fuselage.
Wing jigged with gap for facing rib.
Wing jigged with gap for facing rib.
Brass box glued in position.
Brass box glued in position.
View from right wing tip.
View from right wing tip.

John Vella
Posts: 209
Joined: 20 Mar 2017, 22:09
Location: UK

Re: MU13 Charlesworth

Post by John Vella »

Here we are Bank Holiday and a heat wave ! Model room temperatures are still reasonable so on with the build. The left wing build was done as per the right with the last job being the root facing rib out of 0.8mm ply. The wings were rigged to check any high spots on the wing root. The time consuming job was the profiling of the hard balsa leading edge. The next job is covering in Oratex. The colour scheme German circa 1938. Regards to all the builders out there, John.
Attachments
Glider laterally balanced
Glider laterally balanced
Side view
Side view
Checking the root gap for the facing rib
Checking the root gap for the facing rib
Trailing edges align.
Trailing edges align.
MU-13 rigged
MU-13 rigged

Ben Matu
Posts: 4
Joined: 25 Aug 2019, 09:47
Location: RLP

Re: MU13 Charlesworth

Post by Ben Matu »

Is this an Kit or is the Plan avible to buy? Im looking for an new projekt.

John Vella
Posts: 209
Joined: 20 Mar 2017, 22:09
Location: UK

Re: MU13 Charlesworth

Post by John Vella »

Ben, welcome to the Forum. I see you express interest in a K8 as well as the MU13. I fly the 3.75m Charlesworth K8 and have flown a MU13. They both fly very well. They both require alot of building to make them scale. You could build from the Charlesworth plans or from,the "short kit" by Lasercutsailplanes. Regards John.

Ben Matu
Posts: 4
Joined: 25 Aug 2019, 09:47
Location: RLP

Re: MU13 Charlesworth

Post by Ben Matu »

Thank you for the link. I know that there is a lot of work. I dont want to built full scale. It will be my first old lady.

John Vella
Posts: 209
Joined: 20 Mar 2017, 22:09
Location: UK

Re: MU13 Charlesworth

Post by John Vella »

At last the finishing begins. The fuselage top is skinned in .4 mm ply to blend in with the wings. The cockpit and canopy are painted in flat sky grey acrylic. The rudder push pull system is installed via an indirect 180 deg bellcrank drive. Elevator control is via a carbon push rod to a brass elevator control horn. Access is through a slot in the rear balsa floor. The tailplane is mounted on a balsa seat with steel front pins and a 4M nylon bolt into a captive nut. The fin is attached with a ply tongue located in a ply box and at the rear post a 1mm steel pin mounted in brass tubing.
The diagonal upright into former 7 is supported by a balsa fillet which helps blending the covering at the angle change in that area. The transition under the fuselage wing seat aft from the 0.8mm ply at former 6 is a thin balsa fillet. The covering is in Oratex which works well on compound curves.
The final rigging check is done with wings and fuselage in the garden. The covered empenage are rigged and checked for alignment. The fuselage is covered in four sections with all overlaps going downwards. The radio and servos are fitted and checked. The three servos in the fuselage are Hitec 645mgs.
Attachments
Centre section skin 0.4 ply and cockpit painted.
Centre section skin 0.4 ply and cockpit painted.
Centre section rear view
Centre section rear view
Rear controls and structure
Rear controls and structure
Balsa fillet and wing seat transition
Balsa fillet and wing seat transition
Belly covering
Belly covering
Rig check rear
Rig check rear
Front view
Front view
Tailplane covered and fitted
Tailplane covered and fitted
Rear view
Rear view
Front view
Front view

John Vella
Posts: 209
Joined: 20 Mar 2017, 22:09
Location: UK

Re: MU13 Charlesworth

Post by John Vella »

Thanks Cliff, as you say not to far away to completion. A slow build hopefully gives time to get it right. None of these so called "professional " builds for me. Regards John.

FlyboyDave
Posts: 1
Joined: 24 Mar 2018, 22:26
Location: Leamington Spa

Re: MU13 Charlesworth

Post by FlyboyDave »

Hi John, looks like the MU is coming along nicely :-)

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