Frank- trying to make an 80 year-old retired pilot smile- a 50" span Tiger Moth

[Frank v B]

Back to building,

Put in the hard points in the wings for the interplane "N" struts.  Googled a photo of a Tiger Moth and measured the half span on the screen with a ruler and the position of the struts.  They were 61% of span from the centreline of the wing.  So 15" out.

Cut open the bottom of both wings and glued in balsa blocks where the hard points were required.  Set them aside for the carpenter's glue to dry overnight (did not use 5 minute epoxy).

Photo 23- the hard point in the bottom of the upper wing.
Photo 24- hard point in the bottom wing.

Frank

[Frank v B]

Closing up the upper wing.

Photo 25- patching the hard point on the starboard wing panel
Photo 26- Patching the hard point on the port wing panel.  Note the small strip glued to the bottom of the wing sheeting.  This is so the patch has something to glue to.
Photo 27- Centre section patches in place.  The cuts are angled on purpose so they can be glued back tightly by closing the gap created by the cut.
Photo 28- One wing tip has a 3/32 sheet glued to it.  This will be sanded flush.  Better than using filler to transition from the wing to the tip.

Bottom wing is next.

Frank

[Frank v B]

Did some fuse stuff while the wing was drying:

Photo 30- removed the formers for the turtle deck and two loose cross braces.  Installed longeron doublers just ahead of the stab.  These doublers were to re-inforce the joint in the middle of nowhere. (pencil points to the joint)
Photo 31- made new turtle deck formers and used stringers to make the curve.  No Andy, there is no hidden message in the arrangement of the coloured pins.... or, spend a couple of hours trying to figure out whether anything is being spelled out.  You are retired and looking for stuff to do to fill your time. 

Frank

[Frank v B]

The power calculation is next.

The finished plane will weigh about 3.75-4.0 lbs, conservatively.  This means it will need between 325 and 400 watts to fly properly plus some reserve to get out of trouble.  That is about 90-100 watts per pound.

Just checked the website.  A Power 25 from E-flite is a 32 amp continuous motor.  That is 355 watts (amps x volts) on 3 cells or 460 watts on 4 cells.  It will probably fly nicely on 3 cells (yeah!).

Now to dive into my motor and ESC drawer.

Found one- A Turnigy 35 48-800kv approx 40 amp continuous.  Probably some swap meet item that fell into my pocket.... to replace the money that fell out.

Frank

[Frank v B]

Motor mount.

The motor had to measure 5  3/8" from the firewall to the prop washer.  The cowl pinches so much at the front that a metal mount could not be used.
Made my own out of 3/4" square hard balsa and 1/4" plywood.  See the parts in the photo 33.  The final motor mount in photo 34- next to the fibreglass cowl.

Cut holes in the wing ribs to feed the servo wires through.  See photo 32.  Note the buried connector has been wrapped with dental floss so it won't come apart.

Frank

[Frank v B]

More details:

Photo 35- had to re-inforce the centre section of the elevators.  Used 1/32 plywood on both sides with a strip of fibreglass under it.  Note the rudder extension pinned in place.  All hinges have to be in a straight line otherwise they will not work.  The triangle was added at the bottom of the rudder.  Once dry it will be sanded to shape.  Then I will add fibreglass and plywood. 
Photo 36- used dental floss to bind the cabane struts together. Top and bottom, front and back.  8 points with dental floss.  Used it to tie it together since I could not see how good the glue joints were.
Photo 37- Close-up of new covering between the two cockpits.  Two layers of 1/16" balsa.  Put new balsa along the sides as well.
Photo 38- The motor is in.  The cowl is in.  The prop makes it look even more finished.
Photo 39- new backing of the rear cockpit bulkhead to cover the new stringers for the turtledeck.

There is a finish line somewhere ahead.


Frank

[davidk]

Beautiful... it's lookin' like an airplane.

[bweaver]

More details:

Photo 35- had to re-inforce the centre section of the elevators.  Used 1/32 plywood on both sides with a strip of fibreglass under it.  Note the rudder extension pinned in place.  All hinges have to be in a straight line otherwise they will not work.  The triangle was added at the bottom of the rudder.  Once dry it will be sanded to shape.  Then I will add fibreglass and plywood. 
Photo 36- used dental floss to bind the cabane struts together. Top and bottom, front and back.  8 points with dental floss.  Used it to tie it together since I could not see how good the glue joints were.
Photo 37- Close-up of new covering between the two cockpits.  Two layers of 1/16" balsa.  Put new balsa along the sides as well.
Photo 38- The motor is in.  The cowl is in.  The prop makes it look even more finished.
Photo 39- new backing of the rear cockpit bulkhead to cover the new stringers for the turtledeck.

There is a finish line somewhere ahead.


Frank

And there is enough left over for a good flossing as well.   

When I use floss for reinforcing purposes, I finish up by applying thin cyanoacrylate to the bound area to reinforce it.  I don't trust my knots. I am sure Frank does the same thing.

Nice project there Frank. 

[GuyOReilly]

Great Job Frank!  See you tonight.

[Frank v B]

Time to start thinking about the colour combo.  Have opted for the classic yellow with black cowl... and it has been approved by the owner.  I somehow don't think he would be picky.

Frank

[Frank v B]

Keep moving.......

Completed the following:
- placed balsa fillers everywhere there were gaps
- installed the servo rails for the elevator and rudder.
- filled in the gaps around the landing gear.
- installed the aileron servos
- installed the lower wing supports for the retaining screw
- sanded the elevator and rudder
- removed all the hinges (rudder, elevator, ailerons).

Next are the filling and final sanding.  Then covering will start.

Photo
68- balsa filler pieces on the starboard side pinned and glued in place.
69- filler on the port side.
70- servo rails in place
71- aileron servos glued in place.  Wing bottom will be sheeted.
73- balsa fillers for the wing hold down screws.  Note the disjointed joints.  Nothing was braced.  This wing will be braced will fibreglass over the center sheeting.  Note the large new dihedral brace glued in place.

Frank

[Frank v B]

Went to Home Depot this morning and bought the filler.  It is in the paint section.  There are about 5 of them.  Pick them up.  If it feels empty....that's the one.  "Dap Fast 'n Final Lightweight Spackling" with a bright red lid.

Probably should have bought the 5 gallon bucket with the built-in wheels.   

Frank

[davidk]

That's the one I got, 'cause you guys told me to get it.  Amazing stuff.  Works well with EPO foam, you can sand it.  Fixed up the cowl of my Timber and with a bit of dollar store paint it looks excellent.

[Frank v B]

Covering the bottom of the bottom wing now that the servos, wiring and strut braces are in place.

Photos of the balsa pin cushion!! 

Frank

[Frank v B]

The second half of the wing pincushion.

Frank