Frank's Chica build

[Frank v B]

Have started building my Chica. 

Done so far:

- drew the full size wing plans.  The plans only show half a wing.
- cut out all the ribs and made 20 at once using the rib templates Rob used as well.
- the ribs are in place along with the two main spars and trailing edge.

Some decisions I have made along the way after carefully looking at the plans and talking to Rob:
- a bolt-on wing- I cannot store any more one piece planes.  A personal storage issue. I will be using 4 nylon bolts so the wing actually holds the fuse together.  When I saw Rob's fuse I decided it was deep enough below the wing to make the wing removable.  Thanks Rob!
- changed it to a "D tube" wing from the full slotted main spar and slotted ribs which is very European and very control-line and difficult to cut accurately.
- eliminated the two centre ribs- I will be laying some carbon fibre veil between the main spar and the leading edge sheeting for strength.
- increased the sweep of the wing tips and matched the tail plane with the same swept tips.  The stab, as designed, was a plain rectangle.
- two aileron servos in the wing to eliminate the torque rods.  Much easier.
- battery hatch on top per Rob's plane to change batteries.
- A snarli-able motor.  Will be trying an E-Flite .15 motor (DF) which has the same diameter as the Series 6 (28mm, 400 watt max.) but can go up to 4 S and 800 watts.  Why not!  Live dangerously.  You can always throttle back.....if you have to!  Will fly on 3S....but.... you never know.  I could get Hinchcliffe-itis

Have taken photos but will have to take the course from my son "Downloading photographs for idiots" before I can share them with you.

Frank

[Frank v B]

Here we go with the photos!!


Photo 1- drawing the full size wing plan: i) draw the main spar full span, in this case 39"  ii) draw the rib location starting at the center.  The middle two ribs are spaced exactly as far out as the fuselage sides.  The ribs are drawn with a plastic triangle against the main spar and a one foot metal ruler against the other side to make the ribs perfectly perpendicular to the main spar.
The pen is pointed at the middle of the wing.

No need for the trailing edge or leading edge to be drawn in because the ribs are all the same.  The ribs determine their proper location.

The stack of ribs is shown to the right.

Photo 2  Shows the ribs drawn in with 2" spacing, roughly equal to the original plan.  This photo shows the left wing half.  The angled line at the left end is the wingtip.

Photo 3 shows the finished wing plan.  The two spars are up against a 3' steel ruler.  The 1/4" spars were not straight.  As long as the bends are opposed, the wing will be straight.  The plan has been covered with a sheet of waxed paper to stop the glue from sticking to the plan.

Photo 4- start with the main spar.  Regardless of what the plans indicate, pin the opposite ends (wingtip ends) of the spar in place, then put a metal yardstick to the bottom main spar and and pin the middle in place.  The spar must be absolutely straight.

[Frank v B]

Wing build

photo 5- this mock-up shows how to build a symmetrical wing.  The trailing edge needs to be raised so the main spar can be pinned to the board.  Put a spacer underneath the trailing edge so the rib can rest on it.  The spacer is wider than the trailing edge so the rib can rest on it. Note the waxed paper between the trailing edge and the wood used to raise the trailing edge from the board so errant glue won't stick to it.

photo 6: The trailing edge was glued together from two pieces (39" span, 36"wood!) using epoxy and a doubler used as a brace.  Sylvester is pointing to the joint.

photo 7 : I used a 1/8" piece of balsa 1" wide as a false leading edge.  It is pinned flat on the board and sticks out above the ribs until the glue has dried.  This will then be planed and sanded even with the ribs.  The real leading edge will be added after the top and bottom sheeting has been added.

Photo 8: the finished basic wing drying overnight.  Note: I use carpenters glue because my wife is allergic to CA, luckily not model airplanes. .  Note the word "TOP" written on the top spar.  This is so that the orientation will be correct so the bends in the top and bottom spars are opposed to make a straight wing.  Also note the photo shows the leading edge flat on the building board.

[Frank v B]

Photo 9- The leading edge sheeting on the top of the wing.  Note the carbon veil on top of the main spar.  The sheet is put in place and pinned down.

Photo 10- the leading edge sheeting pinned in place.  To avoid the sheeting getting wavy between the ribs, the metal yardstick is stood on edge and clamped to the false leading edge.  This gives even pressure while the glue dries overnight.

Photo 11 The trailing edge is prepped for a 3/4" wide piece of 1/16 balsa.  Note the carbon veil over the center section joint.  This is all pinned in place.

Photo 12- the wing ready to dry overnight.  Make sure the main spar, trailing edge and leading edge are pinned down to the board so the wing stays straight while it dries.  Next step is to turn it over and do the same sheeting work to the bottom side.

Frank

[octagon]

looks good Frank. Different than mine a bit (by about 550 watts and 1S).

[Frank v B]

Strengthening the wing:

Photo 13 - re-inforcement of the wing centre part to allow the wing to be screwed in.  It is lite ply with the center cut out.  There will be 4 bolts.  Two on the leading edge, two on the trailing edge.

Photo 14  Photo taken of the bottom of the wing.  The parts to fill in the leading edge (2 pieces) and the trailing edge (1 piece).  This fill is to make sure wing does not crush when the 4 wing bolts are tightened.  Also visible is the doubler for the main spar that covers 7 bays.  The little piece left of center at the bottom of the wing is a piece of rib I accidentally broke when cutting the slots for the spar doubler.  I'm only human!

Photo 15 spar doubler epoxied in place with 4 clamps to hold it until it dries.  Yes I slipped some carbon veil between the spar and the spar doubler.

Photo 16- For those of you who have never seen or used carbon veil, this is a photo of my hand under a sheet of carbon veil.

Now off to dinner while the wing dries.

Next step- shear webs.

Frank

[Frank v B]

Dinner's over!  Back to work.

Photo 17- shows the shear webs in place.  I did the overlap type because they are easier and faster.... unlike Rob's between the spar shear webs that are a lot slower to install.  From Rob's post  ".....and tomorrow will do the shear webs (I don't quite know why, but I hate installing shear webs, so tedious I guess)."

Photo 18 Trailing edge in place.  A light sand, a 3/8" wide piece of carbon veil over the trailing edge and then the trailing edge sheeting on top.  Pinned to the board and weighted down so it can dry overnight.

Next steps- bottom sheeting, center sheeting, wing tips and servo installation.

Frank

[Frank v B]

Photos below show the progress:

Photo 19- photo taken with wing upside down.  Top sheeting installed, trailing edge glued to the centre portion of the wing, two servos installed.  The servos are glued to the rib with 5 minute epoxy, then balsa wood webbing was glued around the servo to lock it in and re-inforce the rib.  In my last several airplanes I have glued the servos in because it is lot easier. Servos are cheap.  If one fails, I will cut it out and put in a hatch. 

Also note the servo is put in with the servo arm parallel to the wing service.  This makes for easy adjustment, easy arm replacement and push-rod adjustment.  If the arm is perpendicular to the wing you can't get at the screw easily.

The trailing edge is glued to the centre portion of the wing.

Photo 20 Aileron edge photo- Killing two problems with one stone- I only had a 36" section of aileron stock but the wing is 39" wide.  The centre section is from wider aileron stock.  I glued triangular stock to the aileron's leading edge (shown as the darkened triangle).  This extended the aileron by 3/8" and angled it at the same time.  Saved a lot of sanding time and dust.

[Frank v B]

Starting the fuselage

Photo 21- tape the fuse plans together to make it whole.  To transfer the fuselage to the balsa, I placed the plan on top of the balsa wood with the long edge on the datum line, used a pin to mark the corners, the former locations (double dots at the straight edge) and the rocker bottom.

Photo 22 - mark the pinholes on the balsa with a pen or magic marker.

Photo 23 - make the rocker bottom by placing a pin in the balsa at the start of the rocker and bend a metal ruler with one hand.  Run your pen along once you match the dots with the bend in the ruler.  Yes, it is quick and easy.

Photo 24 connect all the dots with a pen or magic marker.  Also, mark the location of the formers with a double line and a rectangle against the datum line to make sure they are vertical.

Photo 25- cut out the first side.  I do this free-hand with an Exacto 11 blade.  Once cut out and marked, sand the edge smooth to take out any cutting errors.  Now put the first finished side on a new section of balsa wood and trace it with a pen and cut it out.  Cut this side inside the pen lines.  Then put the two sides on top of each other and sand them to the same size.

Photo 26 - place the two beside each other and transfer the locations of the formers from the first side to the second side.  By putting one above the other it automatically makes a left and right fuselage side.

Will be going back to work on the wing once it dries.

Frank

[bweaver]

Frank, while I know you have just managed recently to be able to put the pictures in your post, is there any way you can make them bigger?  I'm tired of getting out the magnifying glass to see what you are talking about. 

I think, your build is looking good?

[Andy Hoffer]

Careful Bruce,

You'll overload his cerebral CPU. 

Andy

[Frank v B]

Bruce:
re: " I'm tired of getting out the magnifying glass to see what you are talking about."

Skip the magnifying glass.  Go straight for the white cane!

Andy:
re:"You'll overload his cerebral CPU.  "

I have one of those???

Frank

[Frank v B]

Bruce,

Your own personal eye test:

1) print it out
2) place on wall at 20 feet
3) cover one eye and see if you can read it.

How is this photo?


Frank

[Andy Hoffer]

Tsk, tsk...

More muddy grey...


Andy

[Frank v B]

Andy,

Now that was white.

Frank