Cessna L19 Bird dog- re-start, 48" span, 480 power on 3 cells

[Frank v B]

Time to start building again.

Resuming the L-19 build.  Fuse was finished.  Had not started the tail feathers or wing when spring set in.
I brought the fuse to the Dec. 1 meeting.
The original post was https://temac.ca/smf/index.php?topic=8226.0

Step 1- clean up my shop to make space on my desk.  Added two shelves, replaced one with a deeper one.  This took 2 weeks. 
Step 2- keep cleaning up the shop and installed new drywall (48" x 22") on the table as a pin cushion.
Step 3- Find the plans and the kit.  Un-earthed during the clean-up.
Step 4- Four garbage bags of stuff taken out of the shop.

Photos:
42- everything boxed and labelled
43- ditto
44- ditto, ditto.
50- the fuse as I left it in the spring.  The black on the nose is the black from the laser cutting spread in the glue.  It is smooth
52- battery hatch removed, nose ring removed.  All held in place with rare earth magnets.  The nose ring has registration pins.

Frank

[Frank v B]

Tail feathers done.

The elevator halves are joined with a dowel then the joint is covered in fibreglass and...5 minute epoxy.

F.

[Frank v B]

The wing

Problem- it is a double tapered wing* outboard of the struts.  The top spar is absolutely flat from wingtip to wingtip.  The plans show that it is to be built in 4 parts then butt glued-together.
That is beyond stupid.  Every joint is a built-in weakness.

Solution: Since it is a flat-bottomed wing, I am building it upside down.  I tapered the top main spar from the 1/4" square to 1/16" at the tip.

Why is the solution for a model built in Canada in Australia? 
Everything is upside down, including building in wash-out at the tip.

Only the two ribs at the ends of the tapered section are glued and allowed to dry, then the trailing edge is installed so the rib bottoms are lined up with the trailing edge.  All other ribs just line up between them.

Photo 59- the steel ruler is to measure the bottom of the rib off the building board.  If the front and back measurements are the same- it is level (flat).
Photo 60- the trailing edge is installed between the two ribs.
Photo 61- the trailing edge in the foreground is in the air.  The centre spar in the background is flat on the board.

F.

* a double tapered wing is one that gets thinner and narrower near the tip.

[GordPayne]

Great build Frank. Let's hope it doesn't fly "Australian" in Canadian skies. "Keep the blue side up and the green side down!"  Happy holidays to you, your family and your copious Black Monokote 😀.

[Frank v B]

Thanks Gord.

One wing half is drying.  The upside down building solution worked. 
Flipped it over and built the rest of the wing half.
The wash-out was also correctly built in.  I had visions of building it wrong. 
Remember the wing was built upside down so the left wing was built on the plan of the right wing.  Arghh!

Photo 1- wing half is drying.
Photo 2- proof the wash-out* was built the right way.  The trailing edge is off the plan.

Satisfying to figure out this wing half in the same time Rob spent to build the entire skeleton of a ****ing biplane.

Frank

*wash-out is built into a wing so the trailing edge is higher than the leading edge.  This makes sure that when a plane approaches a stall, the wingtips stall last to keep the plane from rolling on its back.  Trivia: the Northrop flying wing (YB49) had a wash-out of 7 degrees.  Our model planes have 1-2 degrees.

[Andy Hoffer]

The extraordinary transformation of @Frank v B 's shop bodes well for the long-anticipated metamorphosis of his van, currently pupating quietly somewhere in a Tim's parking lot! 

Bravo Frank!

Andy

[Frank v B]

Who woke up Andy*!

Joined the wings today.  Doubled up on the centre joints.

Frank

* I had originally written "Who woke Andy up?" but then I would get endless comments from him about ending a sentence with a preposition.  Not worth it.

[Frank v B]

Post New Year's re-start of a re-start.

Glued in dihedral braces and trailing edge stock.  Letting it dry overnight.

F.

ps: these little green clamps are terrific.  From Dollarama.  Tomato clamps! $1.25 for a dozen of them.

[Frank v B]

added the top sheeting and the cap strips on the port wing (foreground).

F.

[Frank v B]

Death by 100 clamps. 

Finishing the bottom of the wing.  The clamps hold the following in place:
- trailing edge (Port & Starboard)
- hard points for the strut (P&S)
- main spar ply doubler (bottom half, P&S)
- bottom ply doubler on the main spar at the taper in the outboard wing half (P&S)

Letting it dry overnight.

Frank

[Frank v B]

Trick: How to make ailerons without having to sand them to shape.
This kit had ailerons that were 3/8" flat balsa that had to be sanded to a triangular profile.

Solution- glue tri-stock to aileron stock and sand it the edges once the glue dries.  The sanding takes two passes of a sanding block.
The hypotenuse of the tri-stock automatically adds a 45 degree bevel to the aileron stock.

Here are the photos.
No need to match up the wood pieces since they will be cut to the correct size.
The glue used was carpenters glue.

[BJROB]

Thanks Frank for that tip I really have to remember that one ☝️

[Frank v B]

Fiberglassing the centre joint at the trailing edge.

After sanding the wing section.

step 1- apply epoxy* to both the top and bottom trailing edge wider than the glass cloth.  Photo 20
step 2- lay the cloth over over top of the glue.
step 3- lay waxed paper over top of the glass and glue.  Use brand name waxed paper, not dollar store stuff because it does not have enough wax on it.  Photo 21
step 4- squeeze the waxed paper with thumb and forefinger to smooth it out and get rid of air bubbles.
step 5- apply masking tape to stop the waxed paper from making a bubble at the end (see photo 22)

Leave overnight to cure.  When you remove the waxed paper the surface will be butt smooth.

Frank

* Used 20 minutes epoxy.  Yes, I am still feeling fine but my 5 minutes epoxy bottles are suffering anxiety issues.

[Frank v B]

Fibreglassing the servo bay cover so the servo can be glued onto it.

step 1 - sand
step 2 - apply epoxy
step 3-  lay glass cloth over the patch
step 4 - put waxed paper on top and squeeze out the bubbles.

Note- the cloth is a little wider than required.  It is best to let it cure then trim it with a #11 X-Acto blade.

Leave overnight.

[Frank v B]

Starting to look like something that could fly one day.

F.