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Balsa and tissue became an obvious solution for lightness, compared to foamcore. Easy to build and assemble, so easy in fact, that i was done before i ever learned about airplane dope. I would assume that the majority of amateur builders never pick any up, and instead just do a little waterproofing with a can of polyurethane.
I would suggest using SPAR URETHANE. Spar urethane is formulated to cure to a more flexible bond, traditionally for spars on ships, or doors, or outdoor furniture that is going to swell with weather. It also has the bonus of including uv blockers and antioxidants. The tissue will still break easily, but my theory is that it will be MORE resistant to moisture or cracking.
I suggest one light coat, followed WITHIN 15 MINUTES by one more. Dont let the finish cure before adding another layer. This will promote a single final bond instead of independent layers.
This stuff stinks for about 3 days, so leave it where the wife wont mind.
Here is the build utilizing this technique.
Wingspan: 40"
Wing chord: 5.5"
Weight: 196 grams including powerplant
Powerplant: 800mah 2s, emax1806motor
This (my first) build was an attempt at lightening the "tiny trainer" that i received in the flight test kit.
Fuselage is a step-tapered box construction, with a motor mount similar to the swappable power pod. Two strips of 1/16" pine are used to reinforce the holes. Id recommend this on foamies too if you intend on crashing nosefirst.
Main spar is three pieces of lap joined balsa to achieve dihedral. Ribs are cross lap jointed and are single pieces. Center panels of the wing are sheeted with balsa to accomodate rubber band pressure. Struts are arranged to be under tension during a collision. Their purpose may be obsolete if the tissue is tight enough.
Tailplane is constructed in the same way, with controls attached with scotch tape. (Leave plenty of gap for the tape to adhere to itself, or your control will bind.)
Some parts of the tissue may be partially sealed by glue or overlapping tissue. These will not turn transparent when sprayed with alcohol or sealer. Dont soak the material in an attempt to dope them.
Thats the build. If this thread comes alive ill post a flight video.
So far all i can manage is high speed taxis and toss-to-landing, as im in my yard, and dont want to risk a tight turn stall.
I would suggest using SPAR URETHANE. Spar urethane is formulated to cure to a more flexible bond, traditionally for spars on ships, or doors, or outdoor furniture that is going to swell with weather. It also has the bonus of including uv blockers and antioxidants. The tissue will still break easily, but my theory is that it will be MORE resistant to moisture or cracking.
I suggest one light coat, followed WITHIN 15 MINUTES by one more. Dont let the finish cure before adding another layer. This will promote a single final bond instead of independent layers.
This stuff stinks for about 3 days, so leave it where the wife wont mind.
Here is the build utilizing this technique.
Wingspan: 40"
Wing chord: 5.5"
Weight: 196 grams including powerplant
Powerplant: 800mah 2s, emax1806motor
This (my first) build was an attempt at lightening the "tiny trainer" that i received in the flight test kit.

Fuselage is a step-tapered box construction, with a motor mount similar to the swappable power pod. Two strips of 1/16" pine are used to reinforce the holes. Id recommend this on foamies too if you intend on crashing nosefirst.

Main spar is three pieces of lap joined balsa to achieve dihedral. Ribs are cross lap jointed and are single pieces. Center panels of the wing are sheeted with balsa to accomodate rubber band pressure. Struts are arranged to be under tension during a collision. Their purpose may be obsolete if the tissue is tight enough.

Tailplane is constructed in the same way, with controls attached with scotch tape. (Leave plenty of gap for the tape to adhere to itself, or your control will bind.)

Some parts of the tissue may be partially sealed by glue or overlapping tissue. These will not turn transparent when sprayed with alcohol or sealer. Dont soak the material in an attempt to dope them.

Thats the build. If this thread comes alive ill post a flight video.
So far all i can manage is high speed taxis and toss-to-landing, as im in my yard, and dont want to risk a tight turn stall.