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Author Topic: 48" span Cessna L-19 Bird Dog- Let's make some balsa dust!  (Read 1017 times)

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Offline Frank v B

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Re: 48" span Cessna L-19 Bird Dog- Let's make some balsa dust!
« Reply #15 on: February 13, 2022, 10:19:55 PM »
How to figure out the pattern for the dashboard.

There was no drawing for the dashboard.  I glued a blank piece of balsa in place and let it dry.

The top was sloping so I had no idea how high to make it.  The only thing for sure was the width.  It stopped at the fuselage side.
Trick: I cut a bamboo stick to a point (one side only, not in the middle), rested it on the first two formers and scribed the contour into the dashboard balsa.  Cut the corner properly and sanded it to the right height.  Total time- 5 minutes.

F
"Never trade luck for skill"

Offline Frank v B

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Re: 48" span Cessna L-19 Bird Dog- Let's make some balsa dust!
« Reply #16 on: February 17, 2022, 08:19:00 PM »
Have been quiet for a week.  Work and life got busy.

Have completed the following:
- installed the landing gear.  Just sandwiched the wire between two plywood plates, filled the gaps with balsa and let 5 minute epoxy do its job.
- added doublers in the nose.  The plans and the kit appear to be of two separate and distinctly different styles.  The way on the plans will not work.  Go figure.
- sheeted the bottom at the back.
- Have decided on two hatches- battery hatch on the top behind the firewall and one in the bottom behind the landing gear (servo and radio access)

Back to some serious building and tinkering* tonight. 8)

Frank

* tinkering is required when the kit is either poorly deigned (not this kit) or the parts cannot build what is drawn (this is the case).
« Last Edit: February 17, 2022, 09:45:50 PM by Frank v B »
"Never trade luck for skill"

Offline Frank v B

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Re: 48" span Cessna L-19 Bird Dog- Let's make some balsa dust!
« Reply #17 on: February 17, 2022, 10:03:44 PM »
For Guy:

How To Build a Hatch. a battery hatch on the top of a fuselage behind the firewall.  The bare fuselage- photo 56

Note- I do not cut anything accurately.  All the pieces are larger than required.  They will be shaped with a few strokes of a sanding block.  This way it does not have to built accurately.

Step 1- Make the pieces out of balsa.  This hatch uses 5 pieces which are then covered when the front of the fuse is sheeted.  The main pieces are the front and the back.  The only semi accurate cuts are the notches so it sits below the fuselage edge and stops the hatch from movie sideways when finished.
Photo 55 shows the 5 pieces.
Step 2- clamp the front and back pieces in place.  Place waxed paper between them so they are not accidentally glued in place. Photo 57.
Step 3- glue the side and top braces in place.  Make sure there is waxed paper between the wood and the glue. Photo 59- all 3 braces are glued in place.
Step 4- sand to shape  (to come).
Step 5- sheet the front of the fuselage with the hatch structure in place (to come).
Step 6- cut the hatch free from the top sheeting (to come).
Step 7- add magnets to hold the hatch in place. (to come)

F.

« Last Edit: February 17, 2022, 10:07:57 PM by Frank v B »
"Never trade luck for skill"

Offline Frank v B

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Re: 48" span Cessna L-19 Bird Dog- Let's make some balsa dust!
« Reply #18 on: February 17, 2022, 10:33:29 PM »
What the hatch looks like and rough trimming.

Photo 60- the hatch when the glue dried.
Photo 61- the hatch in place.  Note how rough the shape is compared to the fuselage.
Photo 62- mark the formers on the front and the back.
Photo 63- the former marked on the hatch.  It was rough cut slightly larger than this to be safe.
Photo 64- the rough cut hatch in place- ready for sanding to shape.

F.
« Last Edit: February 17, 2022, 11:04:52 PM by Frank v B »
"Never trade luck for skill"

Offline Frank v B

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Re: 48" span Cessna L-19 Bird Dog- Let's make some balsa dust!
« Reply #19 on: February 17, 2022, 11:02:53 PM »
Motor selection

It calls for a 200-250 watt power system.  Have picked an E-Flite 480- 910 kv- a 250 watt motor.
"Always overpower an airplane.  You can always throttle back.... if you have to!"

Frank
"Never trade luck for skill"

Offline Frank v B

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Re: 48" span Cessna L-19 Bird Dog- Let's make some balsa dust!
« Reply #20 on: February 19, 2022, 05:17:00 PM »
Sanding the battery hatch.

step 1- put masking tape on the existing formers so they are not sanded.  Photo photo 65
step 2- put masking tape on the sanding block about the same width.  It needs to rest on the formers but not sand them.  The only sandpaper is in the hatch area
step 3- make some dust! Sanding finished in photo 67.  Note the sanding did get some of the green masking tape.

F.
« Last Edit: February 19, 2022, 09:56:04 PM by Frank v B »
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Offline Frank v B

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Re: 48" span Cessna L-19 Bird Dog- Let's make some balsa dust!
« Reply #21 on: February 19, 2022, 10:01:05 PM »
WTF!

The nose former was wider than the fuselage.  Glued 3/16" balsa to the outside of the fuse from the landing gear to the nose former.  Clamped in place.

Note: I use wood glue.  The clamps are very important because the moisture in the glue will curl the sheet balsa.  The top was clamped.  The bottom was pinned to keep it flat while drying. Photos 69 and 70.

Glued the bottom sheeting ahead of the landing gear in place.  Photo 71

F.
"Never trade luck for skill"

Offline Frank v B

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Re: 48" span Cessna L-19 Bird Dog- Let's make some balsa dust!
« Reply #22 on: February 21, 2022, 09:31:52 PM »
Doing the curvey stuff. 

The curved top of the fuse forward of the cockpit is done in two layers of 1/16" balsa.  The first layer had the seam in the middle.  Tried to do it in one go which did not work well.  This second layer was done with a staggered overlap, one half at a time.  Will do the second half tomorrow.

Before gluing each piece, I soaked both sides with water via a wet towel.  The carpenter's glue helped in curving the wood.  Pinned each new half and will let it dry overnight.

It is starting to look like an airplane.  Did the rough sanding of the rear fuse last night with a razor plane and a sanding block.

F.

« Last Edit: February 21, 2022, 10:59:28 PM by Frank v B »
"Never trade luck for skill"

Offline Frank v B

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Re: 48" span Cessna L-19 Bird Dog- Let's make some balsa dust!
« Reply #23 on: February 21, 2022, 10:58:11 PM »
Cowl,

Had to increase the diameter of the cowl because of the double layer of the cowl top and the extra sheeting on the sides.

Added a layer of 1/16" balsa (cross-grain) to the perimeter of the cowl.

See photo of the cowl pin cushion.  Added 3 rubber bands to keep everything together while the carpenters glue dried.

F.
« Last Edit: February 21, 2022, 11:00:17 PM by Frank v B »
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Offline Frank v B

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Re: 48" span Cessna L-19 Bird Dog- Let's make some balsa dust!
« Reply #24 on: February 23, 2022, 10:01:24 PM »
How to install magnets on a cowl or hatch.... without having to be accurate. (self aligning).

Basic principle-
i) randomly install magnets on one side (in this case the fuse) and glue in place flush with the balsa surface.
ii) place a piece of waxed paper and keep in place with the second set of magnets.  This way the orientation (north/south poles) are automatically correct. The waxed paper is so that if the glue runs it will not glue the cowl to the fuse. Photo 95.
iii) push the cowl in place and dent the balsa to locate the magnets on the cowl.  Photo 93
iv) drill a hole for each magnet in the cowl much larger than the magnets.  The magnets will automatically float in place.... perfectly aligned and in the correct north/south orientation (yes, I have installed them backwards, that's why I use this method).  Photo 94
v) fill the hole with glue (yes, 5 minute epoxy) (Photo 95) and install in place.  I held it in place with the green masking tape. Photo 96
vi) allow to cure vertically so the glue stays in the hole. Photo 97

F.
« Last Edit: February 23, 2022, 10:04:51 PM by Frank v B »
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Offline Frank v B

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Re: 48" span Cessna L-19 Bird Dog- Let's make some balsa dust!
« Reply #25 on: February 24, 2022, 10:17:36 PM »
Same for the magnets in the battery hatch aft of the firewall.

Photo 5000- Waxed paper on the magnets, 5 minute epoxy in the hole for the magnets in the fuselage.
Photo 01- rubber bands to hold the hatch in place while the epoxy dries.

F.
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Offline Frank v B

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Re: 48" span Cessna L-19 Bird Dog- Let's make some balsa dust!
« Reply #26 on: March 12, 2022, 09:41:43 AM »
...after a 1 week illness....probably due to lack of balsa dust in my system.... back at it.

- installed the motor with proper clearances.  An E-Flite Park 480.  A terrific motor for a plane this size.
- all the hatches magnetized and sanded.
- bottom battery hatch made
- stabilizer/elevators finished- used a bamboo dowel (Dollarama) to connect the center section of the elevators.  Once dry, added a layer of fibreglass over the joints.  See photo 15.

Time to put this project aside now that the fuse is finished and the wing is next.

Have to start prepping my planes for spring and the March 20, 11:33 am date at Rogo Field to usher in spring.


Frank
« Last Edit: March 12, 2022, 09:43:54 AM by Frank v B »
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Offline Knightlite

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Re: 48" span Cessna L-19 Bird Dog- Let's make some balsa dust!
« Reply #27 on: May 02, 2022, 01:21:06 PM »
If you don't want conflicting paint schemes you can model it after another famous Bird Dog currently on display at the Naval Aviation Museum in Pensacola, Florida..

https://www.historynet.com/maj-buang-lys-daring-feat-to-save-his-family/

First non-US pilot landing on a US carrier. Non-Carrier aircraft on a carrier.